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Vapor pressure measurements and predictions for the binary and ternary systems containing ionic liquid [EMIM][Tf2N]
Accepted Manuscript Vapor pressure measurements and predictions for the binary and ternary systems containing ionic liquid [EMIM][Tf2N]
Zhigang Lei, Gangqiang Yu, Yue Su, Chengna Dai PII: DOI: Reference:
S0167-7322(16)33504-8 doi: 10.1016/j.molliq.2017.01.110 MOLLIQ 6912
To appear in:
Journal of Molecular Liquids
Received date: Revised date: Accepted date:
8 November 2016 20 January 2017 31 January 2017
Please cite this article as: Zhigang Lei, Gangqiang Yu, Yue Su, Chengna Dai , Vapor pressure measurements and predictions for the binary and ternary systems containing ionic liquid [EMIM][Tf2N]. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Molliq(2017), doi: 10.1016/ j.molliq.2017.01.110
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ACCEPTED MANUSCRIPT Vapor pressure measurements and predictions for the binary and ternary systems containing ionic liquid [EMIM][Tf2N]
Zhigang Lei, Gangqiang Yu, Yue Su, Chengna Dai*
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State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical
ABSTRACT:
The
vapor
pressures
of
SC
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Technology, Box 266, Beijing 100029, China
water
+
1-ethyl-3-methyl-imidazolium
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bis(trifluoromethylsulfonyl)-amide ([EMIM][Tf2N]) binary system at temperatures ranging
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from 323.2 to 358.2 K and mole fraction of ionic liquid (IL) ranging from 0.05 to 0.90 were measured using a modified equilibrium still. The results showed that with the addition of IL,
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the vapor pressure of binary system is lower. The predictive thermodynamic models, i.e.,
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UNIFAC-Lei and COSMO-RS models were used to predict the vapor pressure with the ARDs of 3.55% and 7.69%, respectively. Then, the adsorption amount of H2O in
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[EMIM][Tf2N] and ZIF-7/ZIF-8 mixture were predicted by the lever rule combining the
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UNIFAC-Lei model with GCMC simulation. The predicted results show a satisfactory agreement with the experimental data. Moreover, the vapor pressures of water + [EMIM][Tf2N] + ZIF-7/ZIF-8 ternary systems were measured with the mass fractions of ZIF-7/ZIF-8 from 0.005 to 0.05. However, it was found that the addition of ZIFs into water and IL mixture has little effect on the vapor pressure in the concentration range investigated. Keywords: Vapor pressure; H2O; Ionic liquid (IL); ZIF; UNIFAC-Lei model; GCMC method
*
Corresponding author. Tel.: +86-1064433695. E-mail address: [email protected] (C. Dai). 1
ACCEPTED MANUSCRIPT 1. Introduction Ionic liquid (IL) is a salts composed of bulky organic cation and weakly coordinated non-organic or organic anion, most of which have a melting point below 100 ℃ [1]. ILs have many unique properties such as potential as “designer solvents”, negligible vapor pressure,
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and good thermal and chemical stability, which make them attractive in separation processes
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(e.g., extraction distillation [2-3], liquid-liquid extraction [4-5], solid-liquid extraction [6],
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and gas absorption and separation [7-8]). Compared with organic solvents used in separation processes, ILs, as a new developmental solvent, are environmental friendly and can be used
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to replace toxic solvents [9].
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Vapor-liquid equilibrium (VLE) data on the solutions containing ILs are crucial for the applications of ILs in separation processes. Until now, researchers have reported many VLE
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data on the mixtures containing ILs [10-15]. Recently, it has been proposed to use IL for gas
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drying, for which the most widely used methods in industry is absorption with traditional solvents. Heym et al. [16] reported to use ethyl sulfate based ILs as absorbent for natural gas The
IL
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dying.
[EMIM][Tf2N]
(1-ethyl-3-methyl-imidazolium
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bis(trifluoromethylsulfonyl)-amide) was used for natural gas dehydration in our recently published work [17]. It was reported that the ILs with hydrophilic anions like [Ac]-, [DEPO4]-, or [Cl]- exhibit the highest selectivity (over 105) [17]; however, the thermal stabilities of these ILs are not stable [18,19]. Moreover, the hydrophobic IL [EMIM][Tf2N] with good thermal stability can also exhibit high gas/water selectivity (e.g., CH4/H2O selectivity is over 1000),which is enough for absorbing the trace water in gas. However, the vapor-liquid equilibrium data of water-IL systems are still not complete. In this work, the experimental
2
ACCEPTED MANUSCRIPT vapor-liquid equilibrium (VLE) data of water and the IL ([EMIM][Tf2N]) were measured by vapor pressure method to study the lowering effect of IL on the vapor pressure of water, which has not been investigated heretofore. On the other hand, zeolitic imidazolate frameworks (ZIFs), a new class of metal organic
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frameworks (MOFs), consist of tetrahedral metal ions M (e.g., Zn, Co, and Cu) bridged by
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imidazolate (Im). The frame structure unit of M-Im-M is similar to that of Si-O-Si in zeolite
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framework in that Si atom is replaced by metal ions, while O atom is replaced by Im [19-20]. In recent years, ZIFs have been applied in many fields, such as gas storage and separation,
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heterogeneous catalysis, chemical sensor and drug delivery, due to their thermo stability, high
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porosity and surface areas [18-21]. Many studies have shown that these solid particles can increase the efficiency of gas absorption when suspending them into liquid phase [22-25]. In
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our work, ZIF-7 and ZIF-8, as the most representative materials of ZIFs, were suspended into
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the ionic liquid of [EMIM][Tf2N] to study their adsorption capacity of water and the effect on the vapor pressure of water and IL binary system.
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The aim of this work is to measure the vapor pressure of the binary system of {water +
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[EMIM][Tf2N]} and the ternary systems of {water + [EMIM][Tf2N] + ZIF-7/ZIF-8} at different temperatures and concentrations, and to study the effect of the IL and ZIFs on VLE behavior of these systems. Moreover, both UNIFAC-Lei and COSMO-RS models were used to predict the vapor pressure of these binary systems. GCMC simulation was used to calculate the adsorption amount of water in ZIF-7/ZIF-8. 2. Experiment details 2.1. Materials and purification
3
ACCEPTED MANUSCRIPT The reagents used in our experiment are summarized in Table 1. [EMIM][Tf2N] was dried over a vacuum rotary evaporator at 353.15 K for 12 h, in order to remove traces of water and other volatile impurities prior to use. After drying, the water content of IL was controlled to be less than 400 ppm in mass fraction as measured by a Karl-Fischer titration
in
our
laboratory.
The
ZIF-7
and
ZIF-8
were
synthesized
by
N,
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system
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(type KLS701). Deionized water was obtained from a Milli-Q reverse osmosis purification
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N-dimethyl-formamide, zinc nitrate hexahydrate, benzimidazole or 2-methylimidazole in our laboratory with solvothermal methods [26, 27]. The detailed procedures can be found in
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reference [28].
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2.2. Apparatus and procedure
The experimental vapor pressures were measured by a modified equilibrium still. The
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details of experimental apparatus were shown in Fig 1. The accuracies in temperature and
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pressure were 0.01 K and 0.01 kPa, respectively. Before the experiment, the U-type equilibrium still (U-type tube with a vacuole) was
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washed thoroughly using deionized water and then dried. All the mixtures of {water +
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[EMIM][Tf2N]} and {water + [EMIM][Tf2N] + ZIF-7/ZIF-8} with different compositions were obtained by weighing different reagents with an electronic balance (type FA2104B, Shanghai Precision Scientific Instrument Co., China), with a precision of 0.0001 g. About 40 mL mixtures were put into the U-type equilibrium still, which filled with two-thirds of the vacuole and half of the U-type tube. Open the condenser and put that U-type equilibrium still with appropriate mixtures into a thermostatic water bath at a given heating temperature, which can be measured by a digital temperature indicator (Type DP-AF, Nanjing Sangli
4
ACCEPTED MANUSCRIPT Electronic Equipment Company, China, 2014) with a fluctuation of 0.01 K. Open the vacuum pump until the mixture boils in the still. Then slowly open the needle valve to make the U-type tube at the same level height on both sides. It was assumed to reach the liquid-vapor equilibrium when the liquid level did not change within 20 minutes. The pressure in the
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U-type equilibrium still was measured by a precision digital pressure gauge (type DP-AF,
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Nanjing Sangli Electronic Equipment Company, China, 2014) with a fluctuation of 0.01 kPa.
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The more detailed procedures of the experiment were described in our previous work [10]. The vapor pressure data of pure water were firstly measured from 313.15 to 358.15 K to
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ensure the reliability of experimental apparatus in the reference [10].
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3. Thermodynamic model
When a system has achieved vapor-liquid equilibrium, the vapor phase composition of
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component i can be calculated by
Vi L P Pi S Py ˆ x ˆ P exp RT S S i i i i
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V i i
(1)
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where P is the vapor pressure at system temperature T, Pi S represents the vapor pressure of pure solute i; yi and xi are the mole fractions of component i in the vapor and liquid phases,
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respectively; ˆiV and ˆiS are the fugacity coefficients of component i in the vapor phase and in its saturated state, respectively; and i represents the activity coefficient of component i. Since the vapor pressure of IL, P2S , is assumed to be zero for its negligible volatility, the vapor phase composition can be treated as pure water (i.e., y1 = 1 and y2 = 0). In addition, the experiment was carried out at low pressures, so the Poynting’s correction factor
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Vi L P Pi S ) is approximately equal to 1, and the vapor phase can be treated as ideal RT
( exp
gas. In this case, the fugacity coefficients ( ˆiV and ˆiS ) are also close to 1. Therefore, Eq. (1) can be simplified as
P x1 1P1S
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(2)
where P1S (vapor pressure of pure water) can be calculated by Antoine equation as
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mentioned above.
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3.1. UNIFAC-Lei model for ILs
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The UNIFAC-Lei model for ILs was used to predict the activity coefficients of solutes i and then to calculate the vapor pressure of binary systems containing IL using Eq. (2) [30]. In
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UNIFAC-Lei model, the activity coefficient has two contributions: the combinatorial activity coefficient ln iC (which represents the influence of differences in size and shape of the (which represents energetic
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molecules) and the residual activity coefficient ln iR
interactions), as expressed in Eq. (3). The activity coefficient is calculated as the flowing
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equations.
ln i ln iC ln iR
(3)
V V ln iC 1 Vi ln Vi 5qi 1 i ln i F i Fi
qi ;Vi qj xj
Fi
ri rj x j
j
(4)
(5)
j
ri vki Rk ; qi vki Qk k
(6)
k
ln iR vk ln k ln k i
i
k
6
(7)
ACCEPTED MANUSCRIPT ln k Qk 1 ln m mk m mk m m m nm m
Q X m m m ; X m Qn X n n
(8)
v x i m
i
i
(9)
vk xi i
i
k
nm exp anm T
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(10)
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The details can be seen in our previous work [29, 30]. In these equations, group
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parameters (Rk, Qk) and the binary group interaction parameters (anm, amn) used in this work are listed in Tables 2 and 3, respectively.
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3.2. COSMO-RS model
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The structures of cation and anion were first designed and optimized by Turbomole using the triple-ζ valence potential (TZVP) basis set with Becke and Perdew functional at the
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density functional theory (DFT) level. In COSMO-RS model, the IL molecule is taken on as
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discrete cation and anion. Therefore, the mixture of binary system of {water + [EMIM][Tf2N]} can be described as a hypothetical ternary system consisting of water, [EMIM]+, and [Tf2N]-.
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The activity coefficient of solute i ( itern ) in the hypothetical ternary system can be directly
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obtained through the COSMOthermX program package. The activity coefficient of solute i in binary mixture can be calculated by
bin i
=
xibin
itern xitern xibin
=
itern 2 xibin
2 xitem xibin tem ; x i 1 xitem 2 xibin
(11)
(12)
where xibin and ibin are the mole fraction and activity coefficient of solute i in the binary system of {water + [EMIM][Tf2N]}, respectively; and xitern and itern are the mole fraction
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ACCEPTED MANUSCRIPT and activity coefficient of solute i in the hypothetical ternary system of {water + [EMIM]+ + [Tf2N]-}, respectively. More details on how to calculate the activity coefficient of a solute in an
IL
by
the
COSMO-RS
model
can
be
found
at
the
website
https://www.scm.com/doc/Tutorials/COSMO-RS/Ionic_Liquids.html.
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3.3. GCMC simulation
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In this work, Grand Canoniscal Monte Carlo (GCMC) was adopted to calculate the
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adsorption amount of water in ZIF-7/ZIF-8 with fixed temperature, volume and chemical potential. The structures of ZIF-7 and ZIF-8 were obtained from the Cambridge Structural
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Database System in Materials Studio (MS) 5.5 software [31]. The detailed structural
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parameters were described elsewhere [28]. For water adsorption in ZIF-7, universal force field (UFF) was used to describe the Lennard-Jones potential (LJ) and the size of simulation
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box was 1×1×1 cell dimension [32]; while in ZIF-8, the LJ parameters for the frame work
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atoms were taken from the dreiding force field (DFF) and the size of simulation box was 2×2×2 cell dimension [33]. In order to balance the calculation speed and reliability, the
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calculation steps were set as 2×107 steps. All calculation work was achieved using Materials
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Studio (MS) 5.5 software.
4. Results and discussion 4.1. Vapor pressure of {H2O (1) + [EMIM][Tf2N] (2)} binary system Vapor pressure data for the binary system {H2O (1) + [EMIM][Tf2N] (2)} were carried out within the temperature range from 323.2 to 358.2 K. The measured data of vapor pressures and activity coefficients at different temperatures and concentrations are listed in Table 4, where the water concentrations are expressed in mole fraction. The UNIFAC-Lei and
8
ACCEPTED MANUSCRIPT COSMO-RS models were used to predict the vapor pressure data for the binary systems containing IL, and the results are also given in Table 4. The expanded uncertainties with 0.95 level of confidence of experimental temperature u(T), pressure u(P), and solute mole fraction
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u(x) are obtained for each data point, as well as the relative deviations ( RD
Pcal Pexp Pexp
UNIFAC-Lei and COSMO-RS models. The average relative deviations ( ARD 1
) for the
N
Pcal Pexp
1
Pexp
)
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N
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for the UNIFAC-Lei and COSMO-RS models are 3.55% and 7.69%, respectively. The comparison between experimental and predicted vapor pressures at different
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temperatures for {H2O + [EMIM][Tf2N]} system is presented in Fig. 2. It can be seen that the
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vapor pressure increases with the increase of temperature. It is evident that the addition of IL can decrease the vapor pressure of water. With the increase of mole fraction of water, the
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vapor pressure for the binary mixtures first increases, and then almost remains at certain
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values due to the immiscible of water and [EMIM][Tf2N] in a relatively high concentration range. Two liquid layers appear and IL is in the lower layer. In the water layer, the
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concentration of IL is very low which can be neglected. Thus, the vapor pressure
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approximately equals to that of pure water at the same temperature. In the range of water-IL homogeneous phase, the UNIFAC-Lei model exhibits a very good prediction with experimental data, whereas in the range of heterogeneous phases, the UNIFAC-Lei model overestimates the vapor pressure peak. In the whole range, the COSMO-RS model gives a worse prediction than the UNIFAC-Lei model. This confirms the applicability of UNIFAC-Lei model for describing the VLE behavior for the IL-H2O system in the miscible portion of the phase envelope and in the immiscible portion they cannot give a good
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ACCEPTED MANUSCRIPT prediction. 4.2. Adsorption amounts of H2O in ZIFs and in [EMIM][Tf2N] + ZIF-7/ZIF-8 mixture The calculated adsorption amounts of H2O in ZIF-7/ZIF-8 by GCMC simulation were shown in Fig. 3. It is clear that the adsorption amount of water increases with the increase of
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pressure and the decrease of temperature. In order to display the effect of pressure on the
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adsorption, the center-of-mass distribution of H2O on the channel of ZIF-8 at different
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pressures is presented in Fig. 4, which obtained from the GCMC simulation. From Fig. 3, we can know that the adsorption amounts of H2O are higher in relatively high pressure than that
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of in low pressure. In the lower pressure region, the adsorption of H2O in ZIF-7/ZIF-8 may
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follow the Langmuir isotherm adsorption. Under the same condition, the adsorption amount of water in ZIF-7 is lower than that in ZIF-8. At the molecular scale, the pore sizes of ZIF-7
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and ZIF-8 are 4.31 and 11.6 Å, respectively. Because the kinetic diameter of H2O is 2.65 Å,
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H2O molecules can enter big pores easily. This may explain why the adsorption amount of H2O in ZIF-8 is higher than that in ZIF-7.
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On this basis the solubility of H2O in the mixture of [EMIM][Tf2N] + ZIF-7/ZIF-8 can
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be predicted by the lever rule based on the mass fraction average of IL and ZIFs expressed as:
W1,cal w1,2W2 w1,3W3
(13)
where W1,cal represents the calculated mass fraction of water in ternary system; w1,2 and w1,3 are the mass fractions of water in pure [EMIM][Tf2N] and ZIFs, which can be calculated by the UNIFAC-Lei model and GCMC simulation, respectively; W2 and W3 are the experimental mass fractions of [EMIM]][Tf2N] and ZIFs on H2O-free basis. The calculated data W1,cal with the content of ZIF-7/ZIF-8 ranging from 0.005-0.05 (on
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ACCEPTED MANUSCRIPT H2O-free basis) are given in Tables 5 and 6, together with the relative deviations ( RD
W1,cal W1,exp W1,exp
) between the experimental and calculated results. The calculated H2O
solubility shows a satisfactory agreement with the experimental data, as shown in Fig. 5. This
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indicates that the lever rule is indeed feasible for describing the solubility of H2O in the mixture of IL and ZIF, and no apparent synergic interaction between IL and ZIF is found. The
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average relative deviations for the {H2O + [EMIM][Tf2N] + ZIF-7} and {H2O +
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[EMIM][Tf2N] + ZIF-8} systems are 7.26% and 8.24%, respectively.
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4.3. Ternary vapor pressure of {H2O (1) + [EMIM][Tf2N] (2) + ZIF-7/ZIF-8 (3)} As the vapor pressure of water and [EMIM][Tf2N] binary system in immiscible portion
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are as the same as pure water, all vapor pressure data for the {H2O + [EMIM][Tf2N] + ZIF-7/ZIF-8} ternary systems were experimentally measured in the miscible portion of
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water-IL at mass fractions of ZIF-7/ZIF-8 with w3=0.005, 0.015, 0.03, and 0.05. The measured vapor pressure data at different temperatures are listed in Tables 5 and 6, along with
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the expanded uncertainties with 0.95 level of confidence of experimental temperature, pressure, and concentration, denoted as u(T), u(P), and u(w), respectively. Here, the water
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contents are expressed in mass fraction. To further investigate the influence of ZIF-7/ZIF-8 on vapor pressure, the profiles of vapor pressure versus temperature are shown in Figs. 6 and 7, where the scatter pointed are the experimental data of the {H2O + [EMIM][Tf2N] + ZIF-7/ZIF-8} ternary systems and the solid lines are the predicted results by the UNIFAC-Lei model on ZIF-free basis. It is seen that vapor pressures of ternary systems are almost the same as those of the binary systems, indicating that the addition of ZIFs into water and IL mixture has little effect on the vapor 11
ACCEPTED MANUSCRIPT pressure in the concentration range investigated. It may be due to the amount of ZIFs being very limited (the mass fraction of ZIFs is in the range from 0.005 to 0.05) so that the difference of intermolecular interactions between water and IL (or ZIFs) is not enlarged enough.
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5. Conclusions
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The vapor pressure data for binary systems of {H2O + [EMIM][Tf2N]} were measured
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to investigate the effect of IL on vapor pressure, which are essential for separation process design (e.g., extractive distillation and gas drying processes). It was found that the vapor
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pressure increases with the increase of temperature, and the addition of IL can decrease the
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vapor pressure of water. The predictive thermodynamic models, i.e., UNIFAC-Lei and COSMO-RS, were used to describe the vapor-liquid equilibrium. The average relative
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deviations for UNIFAC-Lei and COSMO-RS models are 3.55% and 7.69%, respectively. In
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the range of water-IL homogeneous phase, the UNIFAC-Lei model exhibits a very good prediction with experimental data, whereas in the range of heterogeneous phases, the
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UNIFAC-Lei model overestimates the vapor pressure peak. In the whole range, the
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COSMO-RS model gives a worse prediction than the UNIFAC-Lei model. This confirms the applicability of UNIFAC-Lei model for describing the VLE behavior for the IL-H2O system in the miscible portion of phase envelope. The adsorption amounts of H2O in ZIF-7 and ZIF-8 were calculated by GCMC simulation. It was found that the adsorption amount of water increases with the increase of pressure and the decrease of temperature. The adsorption amount of water in ZIF-7 is lower than that in ZIF-8. Furthermore, the solubility of H2O in the mixtures of [EMIM][Tf2N] +
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ACCEPTED MANUSCRIPT ZIF-7/ZIF-8 was calculated by the lever rule based on the mass fraction average of IL and ZIFs. The calculated H2O solubility shows a satisfactory agreement with the experimental data, indicating that the lever rule model is reliable. However, the addition of ZIFs into water and IL mixture has little effect on the vapor pressure in the concentration range investigated.
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This work provides the basic thermodynamic data for adsorptive absorption – a new
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separation technology in chemical engineering, to intensify the gas drying process using the
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mixture of IL and ZIF as separating agents. Acknowledgements
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This work is financially supported by the National Natural Science Foundation of China under Grants (Nos. 21476009, 21406007, and U1462104), and by the Higher Education and
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High-quality and World-class Universities (PY201608). References
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of pore size and functionality in isoreticular zeolitic imidazolate frameworks and their carbon dioxide selective capture properties, J. Am. Chem. Soc. 131 (2009) 3875-3877. [25] S.R. Venna, M.A. Carreon, Highly permeable zeolite imidazolate framework-8
CE
membranes for CO2/CH4 separation, J. Am. Chem. Soc. 132 (2010) 76-78. [26] J.F. Demmink, A. Mehra, A.A.C.M. Beenackers, Gas absorption in the presence of
AC
particles showing interfacial affinity: case of fine sulfur precipitates, Chem. Eng. Sci. 53 (1998) 2885-2902. [27] O. Ozkan, A. Calimli, R. Berber, H. Oguz, Effect of inert solid particles at low
concentrations on gas–liquid mass transfer in mechanically agitated reactors, Chem. Eng. Sci. 55 (2000) 2737-2740. [28] G.D. Zhang, W.F. Cai, C.J. Xu, M. Zhou, A general enhancement factor model of the
physical absorption of gases in multiphase systems, Chem. Eng. Sci. 61 (2006) 558-568. [29] J. Zhang, Z. Duan, C. Xu, M. Zhou, Solid effects on gas–liquid mass transfer in catalytic
slurry system of isobutene hydration over fine ion exchange resin particles, Chem. Eng. J. 15
ACCEPTED MANUSCRIPT 136 (2008) 276-281. [30] K.S. Park, Z. Ni, A.P. Côté, J.Y. Choi, R. Huang, F.J. Uribe-Romo, H.K. Chae, M.
O'Keeffe, O.M. Yaghi, Exceptional chemical and thermal stability of zeolitic imidazolate frameworks, Proc. Natl. Acad. Sci. USA 103 (2006) 10186-10191. [31] N. Masciocchi, S. Brumi, E. Cariati, S. Galli, A. Sironi, Extended polymorphism in
PT
copper(II) imidazolate polymers: a spectroscopic and XRPD structural study, Inorg. Chem. 40 (2001) 5897-5905.
RI
[32] Z. Lei, C. Dai, W. Song, Adsorptive absorption: a preliminary experimental and
modeling study on CO2 solubility, Chem. Eng. Sci. 127 (2015) 260-268.
SC
[33] Z. Lei, J. Zhang, Q. Li, B. Chen, UNIFAC model for ionic liquids, Ind. Eng. Chem. Res.
48 (2009) 2697-2704.
NU
[34] J. Gmehling, P. Rasmussen, A. Fredanslund, Vapor-liquid equilibriums by UNIFAC
group contribution. Revision and extension. 2, Ind. Eng. Chem. Process Des. Dev. 21
MA
(1982) 118-127.
[35] Accelrys, Inc., Materials Studio 5.5. Accelrys Inc: San Diego, CA, 2006.
D
[36] S.L. Mayo, B.D. Olafson, W.A. Goddard, DREIDING: a generic force field for
PT E
molecular simulations, J. Phys. Chem. 94 (1990) 8897-8909. [37] P.J. Perez, H. Amrouche, F.R. Siperstein, adsorption of CO2, CH4, and N2 on zeolitic
AC
1560-1571.
CE
imidazolate frameworks: experiments and simulations, Chem. Eur. J. 16 (2010)
16
ACCEPTED MANUSCRIPT Table 1 Specifications of chemical materials used in this work. Structure
N
N
C 2H 5
H 3C
391.31
O O
O S
O
18.02
H
H
O
H3C
73.09
N
H
NU
N,N-Dimethylfor-mamide
CF3
RI
F3 C
Water
O
S N
CH3
N
118.14
MA
Benzimidazole
N H
N
82.10
N H
PT E
D
2-Methylimidazole
297.49
O
N
Zn2+
O
AC
CE
Zinc nitrate hexahydrate
O
O
17
Shanghai Chengjie Chemical Co.Ltd
O
Distilled in the laboratory Beijing Chemical Works Sinopharm Chemical Reagent Tianjin Guangfu Research Institute Guangzhou Xilong Chemical Co. Ltd
SC
[EMIM][Tf2N]
Source
PT
M/gmol-1
Name
N
O
Mass fraction Purity > 0.990, water content 1600 ppm in mass fraction, chloride content < 200 ppm in mass fraction
> 0.995
> 0.980
> 0.980
> 0.999
ACCEPTED MANUSCRIPT Table 2 Group parameters of volume Rk and surface area Qk in the UNIFAC-Lei model. Subgroup
Rk
Qk
CH2
CH3
0.9011
0.8480
CH2
0.6744
0.5400
H2O
H2O
0.9200
1.4000
[MIM][Tf2N]
[MIM][Tf2N]
8.0145
7.3920
7.4134
6.5440
PT
Main group
AC
CE
PT E
D
MA
NU
SC
RI
[IM][Tf2N]
18
ACCEPTED MANUSCRIPT Table 3 Binary group interaction parameters for the UNIFAC-Lei model (anm ≠ amn). anm
CH2
H2O
1318.00a
300.00a
H2O
[MIM][Tf2N]
-60.36b
-392.88b
PT E
D
MA
NU
SC
RI
Group binary interaction parameters obtained from Refs. [31]. Group binary interaction parameters obtained from Refs. [30].
PT
amn
CE
b
Main group n
AC
a
Main group m
19
ACCEPTED MANUSCRIPT Table 4 Experimental data and predicted vapor pressures for the binary system {H2O (1) + [EMIM][Tf2N] (2)}a.
PT
T (K)
100RD 100RD Pexp PCOSM u(T u(P) PUNIFA γ1,UNIFA γ1,COSM (P) (P) (kPa γ1,exp ) (kPa u(x) O (UNIFAC (COSMO C (kPa) C O ) (kPa) (K) ) ) )
4.14
4.06
333.15 5.11
5.15
4.88
338.15 6.33
6.36
5.81
343.15 7.66
7.79
6.88
348.15 9.44
9.48
8.09
11.4 11.46 9.47 5 13.6 358.15 13.76 11.02 3 x1=0.205 0 5.99
AC
323.15 6.03
CE
PT E
353.15
6.13
328.15 7.56
7.53
7.47
333.15 9.41
9.39
9.03
11.6 8 14.2 343.15 2 17.4 348.15 1 20.9 353.15 9 338.15
11.62 10.83 14.27 12.91 17.41 15.28 21.09 17.97
2.5271 2.5691
2.386 1 2.343 2 2.304 1 2.277 6 2.225 3 2.202 4 2.161 4
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
0.07
SC
328.15 4.14
2.556 0 2.481 6 2.419 8 2.387 2 2.318 3 2.309 5 2.280 2 2.224 1
2.4812 2.4336 2.4373 2.3074
NU
3.36
2.3952 2.1898
MA
3.31
2.3549 2.0803 2.3162 1.9785
D
323.15 3.34
RI
x1=0.106 1
2.2791 1.8839 2.2434 1.7959
2.3693 2.4246 2.3334 2.3148 2.2987 2.2108 2.2653 2.1126 2.2332 2.0198 2.2021 1.9325 2.1721 1.8503
20
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
0.08 0.10 0.13 0.15 0.19 0.23 0.27
0.12 0.15 0.19 0.23 0.28 0.35 0.42
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
0.90
0.60
0.00
1.93
0.78
4.50
0.47
8.21
1.70
10.18
0.42
14.30
0.09
17.29
0.95
19.15
0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1
0.66
1.66
0.40
1.19
0.21
4.04
0.51
7.28
0.35
9.21
0.00
12.23
0.48
14.39
ACCEPTED MANUSCRIPT 24.9 7
25.4
21.01
323.15 8.37
8.27
8.57
358.15
2.106 0.0 0.000 2.1432 1.7731 0.50 9 1 1
1.72
15.86
2.233 4 2.203 0 2.166 3 2.139 4 2.111 6 2.078 9 2.052 6 2.022 2
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
1.19
2.39
1.04
0.19
0.53
2.44
0.49
4.98
0.35
7.40
0.04
9.48
0.20
11.74
0.59
13.70
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
1.08
4.11
1.08
1.70
12.91
12.53
0.25
2.20
1.94
2.36
0.53
5.95
0.57
8.33
0.70
10.17
6.34
0.32
6.46
1.79
x1=0.304 2
348.15 353.15 358.15
19.94 18.53 24.38 22.06 29.62 26.09 35.75 30.67
x1=0.402 6
338.15 343.15 348.15 353.15 358.15
13.16
16.05 16.12 19.97 19.58 24.66 23.62 30.23 28.28 36.82 33.56 44.54 39.73
2.1027 1.9544 2.0788 1.8807 2.0555 1.8106 2.0330 1.7440
2.0394 2.1459
D
12.8
2.488 0 2.361 4 2.301 2 1.990 8 1.930 4 1.939 8 1.922 5 1.903 1
PT E
333.15
10.12 10.65
CE
328.15
10.2 3 12.9 4 18.4 3 20.0 2 24.1 9 30.0 7 36.6 1 44.2 3
AC
323.15
2.1273 2.0316
0.26
PT
16.19 15.46
2.1528 2.1124
0.21
0.33
RI
343.15
13.05 12.80
2.1790 2.1968
0.17
0.40
SC
338.15
10.43 10.52
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
NU
333.15
10.5 4 13.1 2 16.2 7 20.0 1 24.3 7 29.5 6 35.5 4
MA
328.15
2.2060 2.2846
2.0202 2.0770 2.0014 2.0100 1.9830 1.9445 1.9650 1.8821 1.9475 1.8214 1.9304 1.7597 1.9136 1.7069
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
0.49 0.59 0.71
0.20 0.26 0.37 0.40 0.48 0.60 0.73 0.88
x1=0.500 2 12.3 1.997 0.0 0.000 11.53 12.35 1.8704 2.0024 0.25 1 1 1 2 15.6 1.986 0.0 0.000 328.15 14.62 15.35 1.8577 1.9502 0.31 3 2 1 2 323.15
21
ACCEPTED MANUSCRIPT
343.15 348.15 353.15 358.15
18.39 18.92 22.93 23.13 28.39 28.05 34.88 33.77 42.57 40.37 51.62 47.95
1.976 7 1.993 9 1.943 4 1.802 4 1.793 5 1.771 9
1.8451 1.8988 1.8327 1.8483 1.8205 1.7989 1.8085 1.7506 1.7967 1.7036 1.7851 1.6580
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
348.15 353.15 358.15 x1=0.707 2
25.16 26.10 31.21 31.85 38.44 38.57 47.02 46.38 57.14 55.40
1.6808 1.8014
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
NU
20.12 21.22
1.6882 1.8378
1.6735 1.7651
MA
343.15
15.96 17.11
1.657 3 1.641 7 1.640 7 1.646 1 1.587 5 1.632 1 1.630 3 1.621 0
1.6662 1.7288 1.6590 1.6929
D
338.15
12.56 13.67
PT E
333.15
12.3 2 15.5 8 19.7 1 24.8 3 29.8 4 37.9 5 46.5 7 56.5 1
CE
328.15
0.50 0.61 0.70 0.85 1.02
SC
x1=0.603 5 323.15
0.39
1.6518 1.6573 1.6447 1.6223 1.6376 1.5878
0.25 0.31 0.39 0.50 0.60 0.76 0.93 1.13
AC
12.2 1.406 0.0 13.1 14.38 1.5022 1.6500 0.25 6 7 1 15.7 1.412 0.0 328.15 16.68 18.12 1.4987 1.6277 0.31 2 8 1 19.6 1.395 0.0 333.15 21.07 22.61 1.4952 1.6051 0.39 5 1 1 1.390 0.0 338.15 24.6 26.39 27.99 1.4917 1.5821 0.49 9 1 30.3 1.379 0.0 343.15 32.81 34.36 1.4881 1.5589 0.61 9 0 1 37.7 1.383 0.0 348.15 40.48 41.88 1.4846 1.5356 0.75 2 6 1 323.15
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
6.60
3.91
8.06
7.26
6.27
7.40
0.37
2.82
0.21
4.97
0.78
6.38
0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1
1.95
10.96
2.44
9.82
2.08
7.66
1.33
5.11
4.59
6.74
1.29
1.63
0.97
0.41
1.11
1.96
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
6.85
17.29
6.11
15.27
7.23
15.06
7.28
13.78
7.96
13.06
7.32
11.03
PT
338.15
19.6 9 24.9 4 30.2 9 34.7 5 42.4 8 51.2 2
RI
333.15
22
ACCEPTED MANUSCRIPT 1.386 0.0 0.000 1.4810 1.5123 0.93 3 1 2 1.383 0.0 0.000 1.4774 1.4890 1.13 3 1 2
6.85
9.11
6.84
7.68
1.238 1 1.245 4 1.241 7 1.225 2 1.235 9 1.233 1 1.220 9 1.225 7
0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1
7.62
17.20
6.89
15.63
7.12
15.01
8.44
15.58
7.40
13.56
7.52
12.78
8.47
12.82
7.92
11.27
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
3.58
7.82
3.44
7.58
3.42
7.35
7.37
11.20
5.83
9.36
4.42
7.62
4.86
7.78
5.64
8.25
1.040 0.0 0.000 1.0562 1.0577 0.24 9 1 2
1.48
1.64
1.106 8 1.107 7 1.107 6 1.066 9 1.081 8 1.096 4 1.091 4 1.083 0
PT E
CE
AC
1.3294 1.4276
0.31 0.40 0.49
SC
1.3280 1.4154
0.24
PT
1.3307 1.4393
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
RI
1.3321 1.4505
1.3266 1.4028
NU
1.3251 1.3898
MA
1.3237 1.3766 1.3222 1.3633
D
46.4 49.61 50.66 3 56.5 358.15 60.41 60.88 4 x1=0.800 4 12.2 323.15 13.14 14.31 1 15.6 328.15 16.76 18.13 8 19.7 333.15 21.2 22.76 9 24.5 338.15 26.59 28.34 2 30.8 343.15 33.1 35.00 2 38.0 348.15 40.9 42.90 4 46.2 353.15 50.19 52.20 7 56.6 358.15 61.18 63.08 9 x1=0.900 5 12.2 323.15 12.72 13.24 8 15.6 328.15 16.23 16.88 9 19.8 333.15 20.54 21.32 6 24.0 338.15 25.79 26.71 2 30.3 343.15 32.12 33.19 5 38.0 348.15 39.73 40.95 5 46.5 353.15 48.79 50.15 3 56.3 358.15 59.53 61.00 5 x1=0.950 0 12.1 323.15 12.37 12.39 9 353.15
1.1455 1.1927 1.1452 1.1907 1.1450 1.1884 1.1447 1.1856 1.1444 1.1826 1.1441 1.1792 1.1438 1.1755 1.1435 1.1716
23
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
0.62 0.76 0.93 1.13
0.25 0.31 0.40 0.48 0.61 0.76 0.93 1.13
ACCEPTED MANUSCRIPT
343.15 348.15 353.15 358.15 a
19.99 20.04 25.1
25.17
31.27 31.36 38.68 38.78 47.51 47.63 57.98 58.08
1.0560 1.0587 1.0560 1.0589 1.0559 1.0589 1.0558 1.0587 1.0557 1.0583 1.0556 1.0575
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
0.31 0.40 0.49 0.62 0.77
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
PT
338.15
19.9 1 24.4 8 31.0 4 38.3 5 47.2 2 57.2 4
1.0561 1.0583
0.94 1.14
1.87
2.06
0.40
0.65
2.53
2.82
0.74
1.03
0.86
1.12
0.61
0.87
1.29
1.47
SC
333.15
1.036 7 1.052 0 1.030 1 1.048 2 1.046 9 1.049 3 1.042 2
RI
328.15 15.5 15.79 15.82
U(T), U(P) and U(x) are the expanded uncertainties with 0.95 level of confidence of the
NU
experimental temperature T, the experimental pressure Pexp, and water mole fraction x1, respectively. PUNIFAC, PCOSMO, γ1,UNIFAC and γ1,COSMO are the predicted vapor pressure and the
MA
predicted activity coefficients by UNIFAC-Lei and COSMO-RS models, respectively. γ1exp is the experimental activity coefficient of water. RD (P) (UNIFAC) and RD (P) (COSMO) are the relative deviations between experimental vapor pressures and the predicted values by
AC
CE
PT E
D
UNIFAC-Lei and COSMO-RS models, respectively.
24
ACCEPTED MANUSCRIPT Table 5 Experimental data and calculated values for the ternary system {H2O (1) + [EMIM][Tf2N] (2) + ZIF-7 (3)}a. W1,cal
0.0050
343.15 348.15 353.15 358.15 338.15 343.15 348.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 338.15 343.15 348.15 353.15 358.15 338.15 348.15 353.15 358.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 338.15 343.15 348.15 353.15 358.15 343.15
7.16 8.70 10.36 12.51 10.45 12.27 15.51 10.58 13.06 16.13 19.58 24.27 29.57 35.28 20.09 24.26 29.54 36.28 43.99 10.45 15.64 18.66 22.37 10.46 13.09 16.22 19.82 24.22 29.47 36.44 20.12 24.32 29.62 36.73 44.02 27.74
0.0050 0.0050 0.0050 0.0050 0.0100 0.0100 0.0100 0.0200 0.0200 0.0200 0.0200 0.0200 0.0200 0.0200 0.0300 0.0300 0.0300 0.0300 0.0300 0.0100 0.0100 0.0100 0.0100 0.0200 0.0200 0.0200 0.0200 0.0200 0.0200 0.0200 0.0300 0.0300 0.0300 0.0300 0.0300 0.0400
0.0049 0.0049 0.0048 0.0049 0.0101 0.0095 0.0100 0.0202 0.0197 0.0191 0.0190 0.0191 0.0192 0.0192 0.0304 0.0289 0.0284 0.0290 0.0292 0.0101 0.0101 0.0099 0.0098 0.0192 0.0192 0.0196 0.0193 0.0193 0.0194 0.0198 0.0293 0.0279 0.0284 0.0296 0.0290 0.0405
MA
D
PT E
CE
AC
0.0150
100RD U(T) (K) (W1) 2.00 0.01 2.00 0.01 4.00 0.01 2.00 0.02 1.00 0.02 5.00 0.02 0.00 0.01 1.00 0.01 1.50 0.01 4.50 0.01 5.00 0.02 4.50 0.02 4.00 0.02 4.00 0.02 1.33 0.02 3.67 0.02 5.33 0.01 3.33 0.01 2.67 0.01 1.00 0.01 1.00 0.01 1.00 0.01 2.00 0.01 4.00 0.01 4.00 0.01 2.00 0.02 3.50 0.02 3.50 0.02 3.00 0.02 1.00 0.02 2.33 0.01 7.00 0.01 5.33 0.01 1.33 0.01 3.33 0.01 1.25 0.01
PT
W1,exp
RI
Pexp
SC
T (K)
NU
W3
25
U(P) (kPa) 0.14 0.17 0.21 0.25 0.21 0.25 0.31 0.21 0.26 0.32 0.39 0.49 0.59 0.71 0.40 0.49 0.59 0.73 0.88 0.21 0.31 0.37 0.45 0.21 0.26 0.32 0.40 0.48 0.59 0.73 0.40 0.49 0.59 0.73 0.88 0.55
U(W1) 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0001 0.0001 0.0001
ACCEPTED MANUSCRIPT 7.25 3.50 9.00 0.00 2.00 2.00 2.00 1.25 1.00 4.00 7.25 10.00 2.00 2.00 0.00 4.00
0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.02
PT
0.0371 0.0386 0.0364 0.0050 0.0051 0.0051 0.0051 0.0395 0.0396 0.0384 0.0371 0.0045 0.0049 0.0049 0.0050 0.0048
0.66 0.82 0.97 0.15 0.18 0.22 0.26 0.55 0.68 0.82 0.98 0.09 0.12 0.15 0.22 0.25
0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0002 0.0002 0.0002 0.0002 0.0002
U(T), U(P) and U(W) are the expanded uncertainties with 0.95 level of confidence of the
NU
a
0.0400 0.0400 0.0400 0.0050 0.0050 0.0050 0.0050 0.0400 0.0400 0.0400 0.0400 0.0050 0.0050 0.0050 0.0050 0.0050
RI
0.0500
33.08 40.90 48.47 7.28 9.08 10.91 13.00 27.63 33.94 40.98 49.00 4.43 5.88 7.26 10.75 12.42
SC
0.0300
348.15 353.15 358.15 343.15 348.15 353.15 358.15 343.15 348.15 353.15 358.15 333.15 338.15 343.15 353.15 358.15
experimental temperature T, the experimental pressure Pexp, and the experimental solute mass
MA
fraction W1,exp, respectively. W1,cal is the calculated mass fraction by lever ruler of the solute.
AC
CE
PT E
D
RD (W1) is the relative deviations between W1,exp and W1,cal.
26
ACCEPTED MANUSCRIPT Table 6 Experimental data and calculated values for the ternary system {H2O (1) + [EMIM][Tf2N] (2) + ZIF-8 (3)}a.
AC
27
0.01 0.01 0.01 0.02 0.01 0.02 0.01 0.01 0.01 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.02 0.01 0.01 0.02 0.02 0.02 0.01 0.01 0.01 0.02 0.02 0.02 0.01 0.01 0.01 0.02 0.01
PT
0.00 2.00 0.00 2.00 2.00 2.00 2.00 2.00 1.00 0.00 0.00 1.00 5.00 1.00 2.00 2.00 3.98 0.50 1.99 1.00 5.97 2.99 3.48 2.49 0.00 2.00 3.00 3.00 2.00 8.00 8.00 2.00 1.50 2.50 1.00 1.00
RI
0.0050 0.0049 0.0050 0.0049 0.0051 0.0049 0.0051 0.0049 0.0099 0.0100 0.0100 0.0101 0.0105 0.0099 0.0102 0.0102 0.0209 0.0202 0.0197 0.0199 0.0189 0.0195 0.0194 0.0196 0.0100 0.0098 0.0097 0.0097 0.0098 0.0092 0.0092 0.0098 0.0203 0.0205 0.0198 0.0198
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0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 0.0201 0.0201 0.0201 0.0201 0.0201 0.0201 0.0201 0.0201 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 0.0200 0.0200 0.0200 0.0200
100RD (W1) U(T) (K)
NU
3.11 3.82 4.86 5.88 7.38 8.61 10.70 12.32 5.38 6.81 8.44 10.46 13.17 15.31 18.84 22.60 8.55 10.58 13.19 16.27 19.67 24.23 29.56 35.52 5.42 6.71 8.33 10.26 12.71 14.82 18.82 22.59 8.42 10.66 13.17 16.16
MA
323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 323.15 328.15 333.15 338.15
W1,cal
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0.0050
0.0150
Pexp (kPa) W1,exp
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T (K)
CE
W3
U(P) (kPa) 0.06 0.08 0.10 0.12 0.15 0.17 0.21 0.25 0.11 0.14 0.17 0.21 0.26 0.31 0.38 0.45 0.17 0.21 0.26 0.33 0.39 0.48 0.59 0.71 0.11 0.13 0.17 0.21 0.25 0.30 0.38 0.45 0.17 0.21 0.26 0.32
U(W1) 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002
ACCEPTED MANUSCRIPT
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0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.02 0.01 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.02 0.01
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1.00 1.50 1.00 1.50 5.35 3.34 4.01 5.02 4.01 4.00 6.00 6.00 8.00 2.00 2.00 4.00 2.00 9.67 8.67 2.00 0.00
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0.0198 0.0197 0.0198 0.0197 0.0283 0.0289 0.0287 0.0284 0.0287 0.0048 0.0053 0.0053 0.0054 0.0049 0.0049 0.0048 0.0049 0.0329 0.0274 0.0294 0.0300
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0.0200 0.0200 0.0200 0.0200 0.0299 0.0299 0.0299 0.0299 0.0299 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0300 0.0300 0.0300 0.0300
0.40 0.49 0.59 0.71 0.32 0.39 0.49 0.60 0.73 0.06 0.08 0.10 0.12 0.14 0.17 0.19 0.23 0.41 0.47 0.59 0.73
0.0002 0.0002 0.0002 0.0002 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0002 0.0002 0.0002 0.0002
U(T), U(P) and U(W1) are the expanded uncertainties with 0.95 level of confidence of the
D
a
20.08 24.41 29.66 35.58 15.85 19.63 24.42 29.75 36.32 3.00 4.02 4.89 6.14 6.82 8.32 9.60 11.65 20.66 23.51 29.71 36.57
MA
0.0300
343.15 348.15 353.15 358.15 333.15 338.15 343.15 348.15 353.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 338.15 343.15 348.15 353.15
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experimental temperature T, the experimental pressure Pexp, and the experimental solute mass fraction W1,exp, respectively. W1,cal is the calculated mass fraction by lever ruler of the solute.
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RD (W1) is the relative deviations between W1,exp and W1,cal.
28
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ACCEPTED MANUSCRIPT
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Fig. 1. Experimental apparatus for the measurement of vapor pressure.
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1, intelligent temperature controller; 2, constant temperature bath glass sink; 3, U-type equilibrium still; 4, condenser; 5, thermocouple thermometer; 6, buffer air tank; 7, vent value;
AC
pump.
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8, needle value; 9, precision digital pressure gauge; 10, pressure buffer tank; 11, vacuum
29
ACCEPTED MANUSCRIPT
60
323.2 K 333.2 K
328.2 K 338.2 K
50
343.2 K 353.2 K
348.2 K 358.2 K
P/kPa
40
PT
solid lines P(UNIFAC) dashed lines P(COSMO)
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dash doted lines P(H2O)
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30
NU
20
0 0.0
MA
10
0.2
0.4
0.6
0.8
1.0
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x1
Fig. 2. Vapor pressures of binary mixtures {water (1) + [EMIM][Tf2N] (2)} at different
CE
temperatures. Scattered points, experimental data; solid lines, predicted by the UNIFAC-Lei
AC
model; dashed lines, predicted by the COSMO-RS model; dash doted lines, vapor pressures of pure water.
30
ACCEPTED MANUSCRIPT
323.15 K 333.15 K 343.15 K 353.15 K
0.035
0.025 0.020 0.015
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wH2O in ZIF-7
0.030
328.15 K 338.15 K 348.15 K 358.15 K
0.010
(a)
20
30
40
0.14
323.15 K 333.15 K 343.15 K 353.15 K
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0.12
328.15 K 338.15 K 348.15 K 358.15 K
0.08
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0.06 0.04 0.02
10
20
(b) 30
40
50
60
P/kPa
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0
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wH2O in ZIF-8
0.10
0.00
60
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P/kPa
50
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10
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0.005
Fig. 3. Adsorption amount of H2O in ZIF-7/ZIF-8 calculated by GCMC simulation. (a). ZIF-7; (b). ZIF-8.
31
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(b)
MA
NU
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(a)
(d)
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(c)
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Fig. 4. Center-of-mass distribution of H2O in ZIF-8 at 323.15 K and different pressures. The red, green, blue, gray, and white colors represent the H2O molecule, Zn, N, C, and H atoms,
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respectively. (a) 15.97 kPa; (b) 25.28 kPa; (c) 38.73 kPa; (d) 57.65 kPa.
32
ACCEPTED MANUSCRIPT
0.04
(a) no error line
0.02
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W1,cal
0.03
±10% error lines
0.01
0.02
0.03
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0.00 0.00
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0.01
0.04
0.04
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W1,exp
(b)
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no error line
0.02
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0.01
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W1,cal
0.03
0.01
0.02
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0.00 0.00
±10% error lines
0.03
0.04
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W1,exp
Fig. 5. Comparison between calculated solubility (W1,cal) and experimental data (W1,exp) with the content of ZIF-7/ZIF-8 ranging from 0.005-0.05 (on H2O-free basis) for the ternary systems. (a). {water (1) + [EMIM][Tf2N] (2) + ZIF-7 (3)}; (b). {water (1) + [EMIM][Tf2N] (2) + ZIF-8 (3)}.
33
ACCEPTED MANUSCRIPT
60
x'1=0.0993 x'1=0.1806 x'1=0.3082
50
x'1=0.4030 pure water solid line: UNIFAC
30
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P/kPa
40
10 330
335
340
345
350
355
(a)
360
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325
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20
60
x'1=0.1822 x'1=0.3104 x'1=0.4055
50
pure water solid line: UNIFAC
30
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20
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P/kPa
40
MA
x'1=0.4789
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T/K
10
330
335
340
345
350
355
360
T/K
AC
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325
(b)
Fig. 6. Vapor pressure versus temperature for {water (1) + [EMIM][Tf2N] (2) + ZIF-7 (3)}. (a). W3 = 0.005; (b). W3 = 0.015. Solid lines, calculated by the UNIFAC-Lei model on ZIF-7-free basis; scattered points, experimental data.
34
ACCEPTED MANUSCRIPT
x'1=0.0993
60
x'1=0.1814 x'1=0.3103
P/kPa
50 40
pure water solid line: UNIFAC
30
PT
20 10
325
330
335
340
345
x'1=0.1822 x'1=0.3104
50
x'1=0.4047
MA
30
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20 10
325
(b)
330
335
340
345
350
355
360
T/K
AC
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0 320
360
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P/kPa
pure water solid line: UNIFAC 40
355
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60
350
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T/K
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(a)
0 320
Fig. 7. Vapor pressure versus temperature for {water (1) + [EMIM][Tf2N] (2) + ZIF-8 (3)}. (a). W3 = 0.005; (b). W3 = 0.015. Solid lines, calculated by the UNIFAC-Lei model on ZIF-8-free basis; scattered points, experimental data.
35
ACCEPTED MANUSCRIPT Highlights ► Vapor pressures of water + [EMIM][Tf2N] were measured and predicted by the UNIFAC-Lei model; ► The adsorption amount of H2O in [EMIM][Tf2N] + ZIF-7/ZIF-8 mixture was measured
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and predicted by the lever rule;
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► This work provides the basic thermodynamic data for adsorptive absorption– a new unit
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operation in chemical engineering.
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Zhigang Lei, Gangqiang Yu, Yue Su, Chengna Dai PII: DOI: Reference:
S0167-7322(16)33504-8 doi: 10.1016/j.molliq.2017.01.110 MOLLIQ 6912
To appear in:
Journal of Molecular Liquids
Received date: Revised date: Accepted date:
8 November 2016 20 January 2017 31 January 2017
Please cite this article as: Zhigang Lei, Gangqiang Yu, Yue Su, Chengna Dai , Vapor pressure measurements and predictions for the binary and ternary systems containing ionic liquid [EMIM][Tf2N]. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Molliq(2017), doi: 10.1016/ j.molliq.2017.01.110
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ACCEPTED MANUSCRIPT Vapor pressure measurements and predictions for the binary and ternary systems containing ionic liquid [EMIM][Tf2N]
Zhigang Lei, Gangqiang Yu, Yue Su, Chengna Dai*
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State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical
ABSTRACT:
The
vapor
pressures
of
SC
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Technology, Box 266, Beijing 100029, China
water
+
1-ethyl-3-methyl-imidazolium
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bis(trifluoromethylsulfonyl)-amide ([EMIM][Tf2N]) binary system at temperatures ranging
MA
from 323.2 to 358.2 K and mole fraction of ionic liquid (IL) ranging from 0.05 to 0.90 were measured using a modified equilibrium still. The results showed that with the addition of IL,
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the vapor pressure of binary system is lower. The predictive thermodynamic models, i.e.,
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UNIFAC-Lei and COSMO-RS models were used to predict the vapor pressure with the ARDs of 3.55% and 7.69%, respectively. Then, the adsorption amount of H2O in
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[EMIM][Tf2N] and ZIF-7/ZIF-8 mixture were predicted by the lever rule combining the
AC
UNIFAC-Lei model with GCMC simulation. The predicted results show a satisfactory agreement with the experimental data. Moreover, the vapor pressures of water + [EMIM][Tf2N] + ZIF-7/ZIF-8 ternary systems were measured with the mass fractions of ZIF-7/ZIF-8 from 0.005 to 0.05. However, it was found that the addition of ZIFs into water and IL mixture has little effect on the vapor pressure in the concentration range investigated. Keywords: Vapor pressure; H2O; Ionic liquid (IL); ZIF; UNIFAC-Lei model; GCMC method
*
Corresponding author. Tel.: +86-1064433695. E-mail address: [email protected] (C. Dai). 1
ACCEPTED MANUSCRIPT 1. Introduction Ionic liquid (IL) is a salts composed of bulky organic cation and weakly coordinated non-organic or organic anion, most of which have a melting point below 100 ℃ [1]. ILs have many unique properties such as potential as “designer solvents”, negligible vapor pressure,
PT
and good thermal and chemical stability, which make them attractive in separation processes
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(e.g., extraction distillation [2-3], liquid-liquid extraction [4-5], solid-liquid extraction [6],
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and gas absorption and separation [7-8]). Compared with organic solvents used in separation processes, ILs, as a new developmental solvent, are environmental friendly and can be used
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to replace toxic solvents [9].
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Vapor-liquid equilibrium (VLE) data on the solutions containing ILs are crucial for the applications of ILs in separation processes. Until now, researchers have reported many VLE
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data on the mixtures containing ILs [10-15]. Recently, it has been proposed to use IL for gas
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drying, for which the most widely used methods in industry is absorption with traditional solvents. Heym et al. [16] reported to use ethyl sulfate based ILs as absorbent for natural gas The
IL
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dying.
[EMIM][Tf2N]
(1-ethyl-3-methyl-imidazolium
AC
bis(trifluoromethylsulfonyl)-amide) was used for natural gas dehydration in our recently published work [17]. It was reported that the ILs with hydrophilic anions like [Ac]-, [DEPO4]-, or [Cl]- exhibit the highest selectivity (over 105) [17]; however, the thermal stabilities of these ILs are not stable [18,19]. Moreover, the hydrophobic IL [EMIM][Tf2N] with good thermal stability can also exhibit high gas/water selectivity (e.g., CH4/H2O selectivity is over 1000),which is enough for absorbing the trace water in gas. However, the vapor-liquid equilibrium data of water-IL systems are still not complete. In this work, the experimental
2
ACCEPTED MANUSCRIPT vapor-liquid equilibrium (VLE) data of water and the IL ([EMIM][Tf2N]) were measured by vapor pressure method to study the lowering effect of IL on the vapor pressure of water, which has not been investigated heretofore. On the other hand, zeolitic imidazolate frameworks (ZIFs), a new class of metal organic
PT
frameworks (MOFs), consist of tetrahedral metal ions M (e.g., Zn, Co, and Cu) bridged by
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imidazolate (Im). The frame structure unit of M-Im-M is similar to that of Si-O-Si in zeolite
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framework in that Si atom is replaced by metal ions, while O atom is replaced by Im [19-20]. In recent years, ZIFs have been applied in many fields, such as gas storage and separation,
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heterogeneous catalysis, chemical sensor and drug delivery, due to their thermo stability, high
MA
porosity and surface areas [18-21]. Many studies have shown that these solid particles can increase the efficiency of gas absorption when suspending them into liquid phase [22-25]. In
D
our work, ZIF-7 and ZIF-8, as the most representative materials of ZIFs, were suspended into
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the ionic liquid of [EMIM][Tf2N] to study their adsorption capacity of water and the effect on the vapor pressure of water and IL binary system.
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The aim of this work is to measure the vapor pressure of the binary system of {water +
AC
[EMIM][Tf2N]} and the ternary systems of {water + [EMIM][Tf2N] + ZIF-7/ZIF-8} at different temperatures and concentrations, and to study the effect of the IL and ZIFs on VLE behavior of these systems. Moreover, both UNIFAC-Lei and COSMO-RS models were used to predict the vapor pressure of these binary systems. GCMC simulation was used to calculate the adsorption amount of water in ZIF-7/ZIF-8. 2. Experiment details 2.1. Materials and purification
3
ACCEPTED MANUSCRIPT The reagents used in our experiment are summarized in Table 1. [EMIM][Tf2N] was dried over a vacuum rotary evaporator at 353.15 K for 12 h, in order to remove traces of water and other volatile impurities prior to use. After drying, the water content of IL was controlled to be less than 400 ppm in mass fraction as measured by a Karl-Fischer titration
in
our
laboratory.
The
ZIF-7
and
ZIF-8
were
synthesized
by
N,
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system
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(type KLS701). Deionized water was obtained from a Milli-Q reverse osmosis purification
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N-dimethyl-formamide, zinc nitrate hexahydrate, benzimidazole or 2-methylimidazole in our laboratory with solvothermal methods [26, 27]. The detailed procedures can be found in
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reference [28].
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2.2. Apparatus and procedure
The experimental vapor pressures were measured by a modified equilibrium still. The
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details of experimental apparatus were shown in Fig 1. The accuracies in temperature and
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pressure were 0.01 K and 0.01 kPa, respectively. Before the experiment, the U-type equilibrium still (U-type tube with a vacuole) was
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washed thoroughly using deionized water and then dried. All the mixtures of {water +
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[EMIM][Tf2N]} and {water + [EMIM][Tf2N] + ZIF-7/ZIF-8} with different compositions were obtained by weighing different reagents with an electronic balance (type FA2104B, Shanghai Precision Scientific Instrument Co., China), with a precision of 0.0001 g. About 40 mL mixtures were put into the U-type equilibrium still, which filled with two-thirds of the vacuole and half of the U-type tube. Open the condenser and put that U-type equilibrium still with appropriate mixtures into a thermostatic water bath at a given heating temperature, which can be measured by a digital temperature indicator (Type DP-AF, Nanjing Sangli
4
ACCEPTED MANUSCRIPT Electronic Equipment Company, China, 2014) with a fluctuation of 0.01 K. Open the vacuum pump until the mixture boils in the still. Then slowly open the needle valve to make the U-type tube at the same level height on both sides. It was assumed to reach the liquid-vapor equilibrium when the liquid level did not change within 20 minutes. The pressure in the
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U-type equilibrium still was measured by a precision digital pressure gauge (type DP-AF,
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Nanjing Sangli Electronic Equipment Company, China, 2014) with a fluctuation of 0.01 kPa.
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The more detailed procedures of the experiment were described in our previous work [10]. The vapor pressure data of pure water were firstly measured from 313.15 to 358.15 K to
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ensure the reliability of experimental apparatus in the reference [10].
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3. Thermodynamic model
When a system has achieved vapor-liquid equilibrium, the vapor phase composition of
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component i can be calculated by
Vi L P Pi S Py ˆ x ˆ P exp RT S S i i i i
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V i i
(1)
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where P is the vapor pressure at system temperature T, Pi S represents the vapor pressure of pure solute i; yi and xi are the mole fractions of component i in the vapor and liquid phases,
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respectively; ˆiV and ˆiS are the fugacity coefficients of component i in the vapor phase and in its saturated state, respectively; and i represents the activity coefficient of component i. Since the vapor pressure of IL, P2S , is assumed to be zero for its negligible volatility, the vapor phase composition can be treated as pure water (i.e., y1 = 1 and y2 = 0). In addition, the experiment was carried out at low pressures, so the Poynting’s correction factor
5
ACCEPTED MANUSCRIPT
Vi L P Pi S ) is approximately equal to 1, and the vapor phase can be treated as ideal RT
( exp
gas. In this case, the fugacity coefficients ( ˆiV and ˆiS ) are also close to 1. Therefore, Eq. (1) can be simplified as
P x1 1P1S
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(2)
where P1S (vapor pressure of pure water) can be calculated by Antoine equation as
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mentioned above.
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3.1. UNIFAC-Lei model for ILs
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The UNIFAC-Lei model for ILs was used to predict the activity coefficients of solutes i and then to calculate the vapor pressure of binary systems containing IL using Eq. (2) [30]. In
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UNIFAC-Lei model, the activity coefficient has two contributions: the combinatorial activity coefficient ln iC (which represents the influence of differences in size and shape of the (which represents energetic
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molecules) and the residual activity coefficient ln iR
interactions), as expressed in Eq. (3). The activity coefficient is calculated as the flowing
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equations.
ln i ln iC ln iR
(3)
V V ln iC 1 Vi ln Vi 5qi 1 i ln i F i Fi
qi ;Vi qj xj
Fi
ri rj x j
j
(4)
(5)
j
ri vki Rk ; qi vki Qk k
(6)
k
ln iR vk ln k ln k i
i
k
6
(7)
ACCEPTED MANUSCRIPT ln k Qk 1 ln m mk m mk m m m nm m
Q X m m m ; X m Qn X n n
(8)
v x i m
i
i
(9)
vk xi i
i
k
nm exp anm T
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(10)
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The details can be seen in our previous work [29, 30]. In these equations, group
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parameters (Rk, Qk) and the binary group interaction parameters (anm, amn) used in this work are listed in Tables 2 and 3, respectively.
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3.2. COSMO-RS model
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The structures of cation and anion were first designed and optimized by Turbomole using the triple-ζ valence potential (TZVP) basis set with Becke and Perdew functional at the
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density functional theory (DFT) level. In COSMO-RS model, the IL molecule is taken on as
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discrete cation and anion. Therefore, the mixture of binary system of {water + [EMIM][Tf2N]} can be described as a hypothetical ternary system consisting of water, [EMIM]+, and [Tf2N]-.
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The activity coefficient of solute i ( itern ) in the hypothetical ternary system can be directly
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obtained through the COSMOthermX program package. The activity coefficient of solute i in binary mixture can be calculated by
bin i
=
xibin
itern xitern xibin
=
itern 2 xibin
2 xitem xibin tem ; x i 1 xitem 2 xibin
(11)
(12)
where xibin and ibin are the mole fraction and activity coefficient of solute i in the binary system of {water + [EMIM][Tf2N]}, respectively; and xitern and itern are the mole fraction
7
ACCEPTED MANUSCRIPT and activity coefficient of solute i in the hypothetical ternary system of {water + [EMIM]+ + [Tf2N]-}, respectively. More details on how to calculate the activity coefficient of a solute in an
IL
by
the
COSMO-RS
model
can
be
found
at
the
website
https://www.scm.com/doc/Tutorials/COSMO-RS/Ionic_Liquids.html.
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3.3. GCMC simulation
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In this work, Grand Canoniscal Monte Carlo (GCMC) was adopted to calculate the
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adsorption amount of water in ZIF-7/ZIF-8 with fixed temperature, volume and chemical potential. The structures of ZIF-7 and ZIF-8 were obtained from the Cambridge Structural
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Database System in Materials Studio (MS) 5.5 software [31]. The detailed structural
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parameters were described elsewhere [28]. For water adsorption in ZIF-7, universal force field (UFF) was used to describe the Lennard-Jones potential (LJ) and the size of simulation
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box was 1×1×1 cell dimension [32]; while in ZIF-8, the LJ parameters for the frame work
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atoms were taken from the dreiding force field (DFF) and the size of simulation box was 2×2×2 cell dimension [33]. In order to balance the calculation speed and reliability, the
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calculation steps were set as 2×107 steps. All calculation work was achieved using Materials
AC
Studio (MS) 5.5 software.
4. Results and discussion 4.1. Vapor pressure of {H2O (1) + [EMIM][Tf2N] (2)} binary system Vapor pressure data for the binary system {H2O (1) + [EMIM][Tf2N] (2)} were carried out within the temperature range from 323.2 to 358.2 K. The measured data of vapor pressures and activity coefficients at different temperatures and concentrations are listed in Table 4, where the water concentrations are expressed in mole fraction. The UNIFAC-Lei and
8
ACCEPTED MANUSCRIPT COSMO-RS models were used to predict the vapor pressure data for the binary systems containing IL, and the results are also given in Table 4. The expanded uncertainties with 0.95 level of confidence of experimental temperature u(T), pressure u(P), and solute mole fraction
PT
u(x) are obtained for each data point, as well as the relative deviations ( RD
Pcal Pexp Pexp
UNIFAC-Lei and COSMO-RS models. The average relative deviations ( ARD 1
) for the
N
Pcal Pexp
1
Pexp
)
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N
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for the UNIFAC-Lei and COSMO-RS models are 3.55% and 7.69%, respectively. The comparison between experimental and predicted vapor pressures at different
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temperatures for {H2O + [EMIM][Tf2N]} system is presented in Fig. 2. It can be seen that the
MA
vapor pressure increases with the increase of temperature. It is evident that the addition of IL can decrease the vapor pressure of water. With the increase of mole fraction of water, the
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vapor pressure for the binary mixtures first increases, and then almost remains at certain
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values due to the immiscible of water and [EMIM][Tf2N] in a relatively high concentration range. Two liquid layers appear and IL is in the lower layer. In the water layer, the
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concentration of IL is very low which can be neglected. Thus, the vapor pressure
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approximately equals to that of pure water at the same temperature. In the range of water-IL homogeneous phase, the UNIFAC-Lei model exhibits a very good prediction with experimental data, whereas in the range of heterogeneous phases, the UNIFAC-Lei model overestimates the vapor pressure peak. In the whole range, the COSMO-RS model gives a worse prediction than the UNIFAC-Lei model. This confirms the applicability of UNIFAC-Lei model for describing the VLE behavior for the IL-H2O system in the miscible portion of the phase envelope and in the immiscible portion they cannot give a good
9
ACCEPTED MANUSCRIPT prediction. 4.2. Adsorption amounts of H2O in ZIFs and in [EMIM][Tf2N] + ZIF-7/ZIF-8 mixture The calculated adsorption amounts of H2O in ZIF-7/ZIF-8 by GCMC simulation were shown in Fig. 3. It is clear that the adsorption amount of water increases with the increase of
PT
pressure and the decrease of temperature. In order to display the effect of pressure on the
RI
adsorption, the center-of-mass distribution of H2O on the channel of ZIF-8 at different
SC
pressures is presented in Fig. 4, which obtained from the GCMC simulation. From Fig. 3, we can know that the adsorption amounts of H2O are higher in relatively high pressure than that
NU
of in low pressure. In the lower pressure region, the adsorption of H2O in ZIF-7/ZIF-8 may
MA
follow the Langmuir isotherm adsorption. Under the same condition, the adsorption amount of water in ZIF-7 is lower than that in ZIF-8. At the molecular scale, the pore sizes of ZIF-7
D
and ZIF-8 are 4.31 and 11.6 Å, respectively. Because the kinetic diameter of H2O is 2.65 Å,
PT E
H2O molecules can enter big pores easily. This may explain why the adsorption amount of H2O in ZIF-8 is higher than that in ZIF-7.
CE
On this basis the solubility of H2O in the mixture of [EMIM][Tf2N] + ZIF-7/ZIF-8 can
AC
be predicted by the lever rule based on the mass fraction average of IL and ZIFs expressed as:
W1,cal w1,2W2 w1,3W3
(13)
where W1,cal represents the calculated mass fraction of water in ternary system; w1,2 and w1,3 are the mass fractions of water in pure [EMIM][Tf2N] and ZIFs, which can be calculated by the UNIFAC-Lei model and GCMC simulation, respectively; W2 and W3 are the experimental mass fractions of [EMIM]][Tf2N] and ZIFs on H2O-free basis. The calculated data W1,cal with the content of ZIF-7/ZIF-8 ranging from 0.005-0.05 (on
10
ACCEPTED MANUSCRIPT H2O-free basis) are given in Tables 5 and 6, together with the relative deviations ( RD
W1,cal W1,exp W1,exp
) between the experimental and calculated results. The calculated H2O
solubility shows a satisfactory agreement with the experimental data, as shown in Fig. 5. This
PT
indicates that the lever rule is indeed feasible for describing the solubility of H2O in the mixture of IL and ZIF, and no apparent synergic interaction between IL and ZIF is found. The
RI
average relative deviations for the {H2O + [EMIM][Tf2N] + ZIF-7} and {H2O +
SC
[EMIM][Tf2N] + ZIF-8} systems are 7.26% and 8.24%, respectively.
NU
4.3. Ternary vapor pressure of {H2O (1) + [EMIM][Tf2N] (2) + ZIF-7/ZIF-8 (3)} As the vapor pressure of water and [EMIM][Tf2N] binary system in immiscible portion
MA
are as the same as pure water, all vapor pressure data for the {H2O + [EMIM][Tf2N] + ZIF-7/ZIF-8} ternary systems were experimentally measured in the miscible portion of
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D
water-IL at mass fractions of ZIF-7/ZIF-8 with w3=0.005, 0.015, 0.03, and 0.05. The measured vapor pressure data at different temperatures are listed in Tables 5 and 6, along with
CE
the expanded uncertainties with 0.95 level of confidence of experimental temperature, pressure, and concentration, denoted as u(T), u(P), and u(w), respectively. Here, the water
AC
contents are expressed in mass fraction. To further investigate the influence of ZIF-7/ZIF-8 on vapor pressure, the profiles of vapor pressure versus temperature are shown in Figs. 6 and 7, where the scatter pointed are the experimental data of the {H2O + [EMIM][Tf2N] + ZIF-7/ZIF-8} ternary systems and the solid lines are the predicted results by the UNIFAC-Lei model on ZIF-free basis. It is seen that vapor pressures of ternary systems are almost the same as those of the binary systems, indicating that the addition of ZIFs into water and IL mixture has little effect on the vapor 11
ACCEPTED MANUSCRIPT pressure in the concentration range investigated. It may be due to the amount of ZIFs being very limited (the mass fraction of ZIFs is in the range from 0.005 to 0.05) so that the difference of intermolecular interactions between water and IL (or ZIFs) is not enlarged enough.
PT
5. Conclusions
RI
The vapor pressure data for binary systems of {H2O + [EMIM][Tf2N]} were measured
SC
to investigate the effect of IL on vapor pressure, which are essential for separation process design (e.g., extractive distillation and gas drying processes). It was found that the vapor
NU
pressure increases with the increase of temperature, and the addition of IL can decrease the
MA
vapor pressure of water. The predictive thermodynamic models, i.e., UNIFAC-Lei and COSMO-RS, were used to describe the vapor-liquid equilibrium. The average relative
D
deviations for UNIFAC-Lei and COSMO-RS models are 3.55% and 7.69%, respectively. In
PT E
the range of water-IL homogeneous phase, the UNIFAC-Lei model exhibits a very good prediction with experimental data, whereas in the range of heterogeneous phases, the
CE
UNIFAC-Lei model overestimates the vapor pressure peak. In the whole range, the
AC
COSMO-RS model gives a worse prediction than the UNIFAC-Lei model. This confirms the applicability of UNIFAC-Lei model for describing the VLE behavior for the IL-H2O system in the miscible portion of phase envelope. The adsorption amounts of H2O in ZIF-7 and ZIF-8 were calculated by GCMC simulation. It was found that the adsorption amount of water increases with the increase of pressure and the decrease of temperature. The adsorption amount of water in ZIF-7 is lower than that in ZIF-8. Furthermore, the solubility of H2O in the mixtures of [EMIM][Tf2N] +
12
ACCEPTED MANUSCRIPT ZIF-7/ZIF-8 was calculated by the lever rule based on the mass fraction average of IL and ZIFs. The calculated H2O solubility shows a satisfactory agreement with the experimental data, indicating that the lever rule model is reliable. However, the addition of ZIFs into water and IL mixture has little effect on the vapor pressure in the concentration range investigated.
PT
This work provides the basic thermodynamic data for adsorptive absorption – a new
RI
separation technology in chemical engineering, to intensify the gas drying process using the
SC
mixture of IL and ZIF as separating agents. Acknowledgements
NU
This work is financially supported by the National Natural Science Foundation of China under Grants (Nos. 21476009, 21406007, and U1462104), and by the Higher Education and
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High-quality and World-class Universities (PY201608). References
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ACCEPTED MANUSCRIPT Table 1 Specifications of chemical materials used in this work. Structure
N
N
C 2H 5
H 3C
391.31
O O
O S
O
18.02
H
H
O
H3C
73.09
N
H
NU
N,N-Dimethylfor-mamide
CF3
RI
F3 C
Water
O
S N
CH3
N
118.14
MA
Benzimidazole
N H
N
82.10
N H
PT E
D
2-Methylimidazole
297.49
O
N
Zn2+
O
AC
CE
Zinc nitrate hexahydrate
O
O
17
Shanghai Chengjie Chemical Co.Ltd
O
Distilled in the laboratory Beijing Chemical Works Sinopharm Chemical Reagent Tianjin Guangfu Research Institute Guangzhou Xilong Chemical Co. Ltd
SC
[EMIM][Tf2N]
Source
PT
M/gmol-1
Name
N
O
Mass fraction Purity > 0.990, water content 1600 ppm in mass fraction, chloride content < 200 ppm in mass fraction
> 0.995
> 0.980
> 0.980
> 0.999
ACCEPTED MANUSCRIPT Table 2 Group parameters of volume Rk and surface area Qk in the UNIFAC-Lei model. Subgroup
Rk
Qk
CH2
CH3
0.9011
0.8480
CH2
0.6744
0.5400
H2O
H2O
0.9200
1.4000
[MIM][Tf2N]
[MIM][Tf2N]
8.0145
7.3920
7.4134
6.5440
PT
Main group
AC
CE
PT E
D
MA
NU
SC
RI
[IM][Tf2N]
18
ACCEPTED MANUSCRIPT Table 3 Binary group interaction parameters for the UNIFAC-Lei model (anm ≠ amn). anm
CH2
H2O
1318.00a
300.00a
H2O
[MIM][Tf2N]
-60.36b
-392.88b
PT E
D
MA
NU
SC
RI
Group binary interaction parameters obtained from Refs. [31]. Group binary interaction parameters obtained from Refs. [30].
PT
amn
CE
b
Main group n
AC
a
Main group m
19
ACCEPTED MANUSCRIPT Table 4 Experimental data and predicted vapor pressures for the binary system {H2O (1) + [EMIM][Tf2N] (2)}a.
PT
T (K)
100RD 100RD Pexp PCOSM u(T u(P) PUNIFA γ1,UNIFA γ1,COSM (P) (P) (kPa γ1,exp ) (kPa u(x) O (UNIFAC (COSMO C (kPa) C O ) (kPa) (K) ) ) )
4.14
4.06
333.15 5.11
5.15
4.88
338.15 6.33
6.36
5.81
343.15 7.66
7.79
6.88
348.15 9.44
9.48
8.09
11.4 11.46 9.47 5 13.6 358.15 13.76 11.02 3 x1=0.205 0 5.99
AC
323.15 6.03
CE
PT E
353.15
6.13
328.15 7.56
7.53
7.47
333.15 9.41
9.39
9.03
11.6 8 14.2 343.15 2 17.4 348.15 1 20.9 353.15 9 338.15
11.62 10.83 14.27 12.91 17.41 15.28 21.09 17.97
2.5271 2.5691
2.386 1 2.343 2 2.304 1 2.277 6 2.225 3 2.202 4 2.161 4
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
0.07
SC
328.15 4.14
2.556 0 2.481 6 2.419 8 2.387 2 2.318 3 2.309 5 2.280 2 2.224 1
2.4812 2.4336 2.4373 2.3074
NU
3.36
2.3952 2.1898
MA
3.31
2.3549 2.0803 2.3162 1.9785
D
323.15 3.34
RI
x1=0.106 1
2.2791 1.8839 2.2434 1.7959
2.3693 2.4246 2.3334 2.3148 2.2987 2.2108 2.2653 2.1126 2.2332 2.0198 2.2021 1.9325 2.1721 1.8503
20
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
0.08 0.10 0.13 0.15 0.19 0.23 0.27
0.12 0.15 0.19 0.23 0.28 0.35 0.42
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
0.90
0.60
0.00
1.93
0.78
4.50
0.47
8.21
1.70
10.18
0.42
14.30
0.09
17.29
0.95
19.15
0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1
0.66
1.66
0.40
1.19
0.21
4.04
0.51
7.28
0.35
9.21
0.00
12.23
0.48
14.39
ACCEPTED MANUSCRIPT 24.9 7
25.4
21.01
323.15 8.37
8.27
8.57
358.15
2.106 0.0 0.000 2.1432 1.7731 0.50 9 1 1
1.72
15.86
2.233 4 2.203 0 2.166 3 2.139 4 2.111 6 2.078 9 2.052 6 2.022 2
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
1.19
2.39
1.04
0.19
0.53
2.44
0.49
4.98
0.35
7.40
0.04
9.48
0.20
11.74
0.59
13.70
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
1.08
4.11
1.08
1.70
12.91
12.53
0.25
2.20
1.94
2.36
0.53
5.95
0.57
8.33
0.70
10.17
6.34
0.32
6.46
1.79
x1=0.304 2
348.15 353.15 358.15
19.94 18.53 24.38 22.06 29.62 26.09 35.75 30.67
x1=0.402 6
338.15 343.15 348.15 353.15 358.15
13.16
16.05 16.12 19.97 19.58 24.66 23.62 30.23 28.28 36.82 33.56 44.54 39.73
2.1027 1.9544 2.0788 1.8807 2.0555 1.8106 2.0330 1.7440
2.0394 2.1459
D
12.8
2.488 0 2.361 4 2.301 2 1.990 8 1.930 4 1.939 8 1.922 5 1.903 1
PT E
333.15
10.12 10.65
CE
328.15
10.2 3 12.9 4 18.4 3 20.0 2 24.1 9 30.0 7 36.6 1 44.2 3
AC
323.15
2.1273 2.0316
0.26
PT
16.19 15.46
2.1528 2.1124
0.21
0.33
RI
343.15
13.05 12.80
2.1790 2.1968
0.17
0.40
SC
338.15
10.43 10.52
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
NU
333.15
10.5 4 13.1 2 16.2 7 20.0 1 24.3 7 29.5 6 35.5 4
MA
328.15
2.2060 2.2846
2.0202 2.0770 2.0014 2.0100 1.9830 1.9445 1.9650 1.8821 1.9475 1.8214 1.9304 1.7597 1.9136 1.7069
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
0.49 0.59 0.71
0.20 0.26 0.37 0.40 0.48 0.60 0.73 0.88
x1=0.500 2 12.3 1.997 0.0 0.000 11.53 12.35 1.8704 2.0024 0.25 1 1 1 2 15.6 1.986 0.0 0.000 328.15 14.62 15.35 1.8577 1.9502 0.31 3 2 1 2 323.15
21
ACCEPTED MANUSCRIPT
343.15 348.15 353.15 358.15
18.39 18.92 22.93 23.13 28.39 28.05 34.88 33.77 42.57 40.37 51.62 47.95
1.976 7 1.993 9 1.943 4 1.802 4 1.793 5 1.771 9
1.8451 1.8988 1.8327 1.8483 1.8205 1.7989 1.8085 1.7506 1.7967 1.7036 1.7851 1.6580
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
348.15 353.15 358.15 x1=0.707 2
25.16 26.10 31.21 31.85 38.44 38.57 47.02 46.38 57.14 55.40
1.6808 1.8014
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
NU
20.12 21.22
1.6882 1.8378
1.6735 1.7651
MA
343.15
15.96 17.11
1.657 3 1.641 7 1.640 7 1.646 1 1.587 5 1.632 1 1.630 3 1.621 0
1.6662 1.7288 1.6590 1.6929
D
338.15
12.56 13.67
PT E
333.15
12.3 2 15.5 8 19.7 1 24.8 3 29.8 4 37.9 5 46.5 7 56.5 1
CE
328.15
0.50 0.61 0.70 0.85 1.02
SC
x1=0.603 5 323.15
0.39
1.6518 1.6573 1.6447 1.6223 1.6376 1.5878
0.25 0.31 0.39 0.50 0.60 0.76 0.93 1.13
AC
12.2 1.406 0.0 13.1 14.38 1.5022 1.6500 0.25 6 7 1 15.7 1.412 0.0 328.15 16.68 18.12 1.4987 1.6277 0.31 2 8 1 19.6 1.395 0.0 333.15 21.07 22.61 1.4952 1.6051 0.39 5 1 1 1.390 0.0 338.15 24.6 26.39 27.99 1.4917 1.5821 0.49 9 1 30.3 1.379 0.0 343.15 32.81 34.36 1.4881 1.5589 0.61 9 0 1 37.7 1.383 0.0 348.15 40.48 41.88 1.4846 1.5356 0.75 2 6 1 323.15
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
6.60
3.91
8.06
7.26
6.27
7.40
0.37
2.82
0.21
4.97
0.78
6.38
0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1
1.95
10.96
2.44
9.82
2.08
7.66
1.33
5.11
4.59
6.74
1.29
1.63
0.97
0.41
1.11
1.96
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
6.85
17.29
6.11
15.27
7.23
15.06
7.28
13.78
7.96
13.06
7.32
11.03
PT
338.15
19.6 9 24.9 4 30.2 9 34.7 5 42.4 8 51.2 2
RI
333.15
22
ACCEPTED MANUSCRIPT 1.386 0.0 0.000 1.4810 1.5123 0.93 3 1 2 1.383 0.0 0.000 1.4774 1.4890 1.13 3 1 2
6.85
9.11
6.84
7.68
1.238 1 1.245 4 1.241 7 1.225 2 1.235 9 1.233 1 1.220 9 1.225 7
0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1 0.000 1
7.62
17.20
6.89
15.63
7.12
15.01
8.44
15.58
7.40
13.56
7.52
12.78
8.47
12.82
7.92
11.27
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
3.58
7.82
3.44
7.58
3.42
7.35
7.37
11.20
5.83
9.36
4.42
7.62
4.86
7.78
5.64
8.25
1.040 0.0 0.000 1.0562 1.0577 0.24 9 1 2
1.48
1.64
1.106 8 1.107 7 1.107 6 1.066 9 1.081 8 1.096 4 1.091 4 1.083 0
PT E
CE
AC
1.3294 1.4276
0.31 0.40 0.49
SC
1.3280 1.4154
0.24
PT
1.3307 1.4393
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
RI
1.3321 1.4505
1.3266 1.4028
NU
1.3251 1.3898
MA
1.3237 1.3766 1.3222 1.3633
D
46.4 49.61 50.66 3 56.5 358.15 60.41 60.88 4 x1=0.800 4 12.2 323.15 13.14 14.31 1 15.6 328.15 16.76 18.13 8 19.7 333.15 21.2 22.76 9 24.5 338.15 26.59 28.34 2 30.8 343.15 33.1 35.00 2 38.0 348.15 40.9 42.90 4 46.2 353.15 50.19 52.20 7 56.6 358.15 61.18 63.08 9 x1=0.900 5 12.2 323.15 12.72 13.24 8 15.6 328.15 16.23 16.88 9 19.8 333.15 20.54 21.32 6 24.0 338.15 25.79 26.71 2 30.3 343.15 32.12 33.19 5 38.0 348.15 39.73 40.95 5 46.5 353.15 48.79 50.15 3 56.3 358.15 59.53 61.00 5 x1=0.950 0 12.1 323.15 12.37 12.39 9 353.15
1.1455 1.1927 1.1452 1.1907 1.1450 1.1884 1.1447 1.1856 1.1444 1.1826 1.1441 1.1792 1.1438 1.1755 1.1435 1.1716
23
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
0.62 0.76 0.93 1.13
0.25 0.31 0.40 0.48 0.61 0.76 0.93 1.13
ACCEPTED MANUSCRIPT
343.15 348.15 353.15 358.15 a
19.99 20.04 25.1
25.17
31.27 31.36 38.68 38.78 47.51 47.63 57.98 58.08
1.0560 1.0587 1.0560 1.0589 1.0559 1.0589 1.0558 1.0587 1.0557 1.0583 1.0556 1.0575
0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1 0.0 1
0.31 0.40 0.49 0.62 0.77
0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2 0.000 2
PT
338.15
19.9 1 24.4 8 31.0 4 38.3 5 47.2 2 57.2 4
1.0561 1.0583
0.94 1.14
1.87
2.06
0.40
0.65
2.53
2.82
0.74
1.03
0.86
1.12
0.61
0.87
1.29
1.47
SC
333.15
1.036 7 1.052 0 1.030 1 1.048 2 1.046 9 1.049 3 1.042 2
RI
328.15 15.5 15.79 15.82
U(T), U(P) and U(x) are the expanded uncertainties with 0.95 level of confidence of the
NU
experimental temperature T, the experimental pressure Pexp, and water mole fraction x1, respectively. PUNIFAC, PCOSMO, γ1,UNIFAC and γ1,COSMO are the predicted vapor pressure and the
MA
predicted activity coefficients by UNIFAC-Lei and COSMO-RS models, respectively. γ1exp is the experimental activity coefficient of water. RD (P) (UNIFAC) and RD (P) (COSMO) are the relative deviations between experimental vapor pressures and the predicted values by
AC
CE
PT E
D
UNIFAC-Lei and COSMO-RS models, respectively.
24
ACCEPTED MANUSCRIPT Table 5 Experimental data and calculated values for the ternary system {H2O (1) + [EMIM][Tf2N] (2) + ZIF-7 (3)}a. W1,cal
0.0050
343.15 348.15 353.15 358.15 338.15 343.15 348.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 338.15 343.15 348.15 353.15 358.15 338.15 348.15 353.15 358.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 338.15 343.15 348.15 353.15 358.15 343.15
7.16 8.70 10.36 12.51 10.45 12.27 15.51 10.58 13.06 16.13 19.58 24.27 29.57 35.28 20.09 24.26 29.54 36.28 43.99 10.45 15.64 18.66 22.37 10.46 13.09 16.22 19.82 24.22 29.47 36.44 20.12 24.32 29.62 36.73 44.02 27.74
0.0050 0.0050 0.0050 0.0050 0.0100 0.0100 0.0100 0.0200 0.0200 0.0200 0.0200 0.0200 0.0200 0.0200 0.0300 0.0300 0.0300 0.0300 0.0300 0.0100 0.0100 0.0100 0.0100 0.0200 0.0200 0.0200 0.0200 0.0200 0.0200 0.0200 0.0300 0.0300 0.0300 0.0300 0.0300 0.0400
0.0049 0.0049 0.0048 0.0049 0.0101 0.0095 0.0100 0.0202 0.0197 0.0191 0.0190 0.0191 0.0192 0.0192 0.0304 0.0289 0.0284 0.0290 0.0292 0.0101 0.0101 0.0099 0.0098 0.0192 0.0192 0.0196 0.0193 0.0193 0.0194 0.0198 0.0293 0.0279 0.0284 0.0296 0.0290 0.0405
MA
D
PT E
CE
AC
0.0150
100RD U(T) (K) (W1) 2.00 0.01 2.00 0.01 4.00 0.01 2.00 0.02 1.00 0.02 5.00 0.02 0.00 0.01 1.00 0.01 1.50 0.01 4.50 0.01 5.00 0.02 4.50 0.02 4.00 0.02 4.00 0.02 1.33 0.02 3.67 0.02 5.33 0.01 3.33 0.01 2.67 0.01 1.00 0.01 1.00 0.01 1.00 0.01 2.00 0.01 4.00 0.01 4.00 0.01 2.00 0.02 3.50 0.02 3.50 0.02 3.00 0.02 1.00 0.02 2.33 0.01 7.00 0.01 5.33 0.01 1.33 0.01 3.33 0.01 1.25 0.01
PT
W1,exp
RI
Pexp
SC
T (K)
NU
W3
25
U(P) (kPa) 0.14 0.17 0.21 0.25 0.21 0.25 0.31 0.21 0.26 0.32 0.39 0.49 0.59 0.71 0.40 0.49 0.59 0.73 0.88 0.21 0.31 0.37 0.45 0.21 0.26 0.32 0.40 0.48 0.59 0.73 0.40 0.49 0.59 0.73 0.88 0.55
U(W1) 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0001 0.0001 0.0001
ACCEPTED MANUSCRIPT 7.25 3.50 9.00 0.00 2.00 2.00 2.00 1.25 1.00 4.00 7.25 10.00 2.00 2.00 0.00 4.00
0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.02
PT
0.0371 0.0386 0.0364 0.0050 0.0051 0.0051 0.0051 0.0395 0.0396 0.0384 0.0371 0.0045 0.0049 0.0049 0.0050 0.0048
0.66 0.82 0.97 0.15 0.18 0.22 0.26 0.55 0.68 0.82 0.98 0.09 0.12 0.15 0.22 0.25
0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0002 0.0002 0.0002 0.0002 0.0002
U(T), U(P) and U(W) are the expanded uncertainties with 0.95 level of confidence of the
NU
a
0.0400 0.0400 0.0400 0.0050 0.0050 0.0050 0.0050 0.0400 0.0400 0.0400 0.0400 0.0050 0.0050 0.0050 0.0050 0.0050
RI
0.0500
33.08 40.90 48.47 7.28 9.08 10.91 13.00 27.63 33.94 40.98 49.00 4.43 5.88 7.26 10.75 12.42
SC
0.0300
348.15 353.15 358.15 343.15 348.15 353.15 358.15 343.15 348.15 353.15 358.15 333.15 338.15 343.15 353.15 358.15
experimental temperature T, the experimental pressure Pexp, and the experimental solute mass
MA
fraction W1,exp, respectively. W1,cal is the calculated mass fraction by lever ruler of the solute.
AC
CE
PT E
D
RD (W1) is the relative deviations between W1,exp and W1,cal.
26
ACCEPTED MANUSCRIPT Table 6 Experimental data and calculated values for the ternary system {H2O (1) + [EMIM][Tf2N] (2) + ZIF-8 (3)}a.
AC
27
0.01 0.01 0.01 0.02 0.01 0.02 0.01 0.01 0.01 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.02 0.01 0.01 0.02 0.02 0.02 0.01 0.01 0.01 0.02 0.02 0.02 0.01 0.01 0.01 0.02 0.01
PT
0.00 2.00 0.00 2.00 2.00 2.00 2.00 2.00 1.00 0.00 0.00 1.00 5.00 1.00 2.00 2.00 3.98 0.50 1.99 1.00 5.97 2.99 3.48 2.49 0.00 2.00 3.00 3.00 2.00 8.00 8.00 2.00 1.50 2.50 1.00 1.00
RI
0.0050 0.0049 0.0050 0.0049 0.0051 0.0049 0.0051 0.0049 0.0099 0.0100 0.0100 0.0101 0.0105 0.0099 0.0102 0.0102 0.0209 0.0202 0.0197 0.0199 0.0189 0.0195 0.0194 0.0196 0.0100 0.0098 0.0097 0.0097 0.0098 0.0092 0.0092 0.0098 0.0203 0.0205 0.0198 0.0198
SC
0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 0.0201 0.0201 0.0201 0.0201 0.0201 0.0201 0.0201 0.0201 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 0.0200 0.0200 0.0200 0.0200
100RD (W1) U(T) (K)
NU
3.11 3.82 4.86 5.88 7.38 8.61 10.70 12.32 5.38 6.81 8.44 10.46 13.17 15.31 18.84 22.60 8.55 10.58 13.19 16.27 19.67 24.23 29.56 35.52 5.42 6.71 8.33 10.26 12.71 14.82 18.82 22.59 8.42 10.66 13.17 16.16
MA
323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 323.15 328.15 333.15 338.15
W1,cal
D
0.0050
0.0150
Pexp (kPa) W1,exp
PT E
T (K)
CE
W3
U(P) (kPa) 0.06 0.08 0.10 0.12 0.15 0.17 0.21 0.25 0.11 0.14 0.17 0.21 0.26 0.31 0.38 0.45 0.17 0.21 0.26 0.33 0.39 0.48 0.59 0.71 0.11 0.13 0.17 0.21 0.25 0.30 0.38 0.45 0.17 0.21 0.26 0.32
U(W1) 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002
ACCEPTED MANUSCRIPT
PT
0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.02 0.01 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.02 0.01
RI
1.00 1.50 1.00 1.50 5.35 3.34 4.01 5.02 4.01 4.00 6.00 6.00 8.00 2.00 2.00 4.00 2.00 9.67 8.67 2.00 0.00
SC
0.0198 0.0197 0.0198 0.0197 0.0283 0.0289 0.0287 0.0284 0.0287 0.0048 0.0053 0.0053 0.0054 0.0049 0.0049 0.0048 0.0049 0.0329 0.0274 0.0294 0.0300
NU
0.0200 0.0200 0.0200 0.0200 0.0299 0.0299 0.0299 0.0299 0.0299 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0300 0.0300 0.0300 0.0300
0.40 0.49 0.59 0.71 0.32 0.39 0.49 0.60 0.73 0.06 0.08 0.10 0.12 0.14 0.17 0.19 0.23 0.41 0.47 0.59 0.73
0.0002 0.0002 0.0002 0.0002 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0002 0.0002 0.0002 0.0002
U(T), U(P) and U(W1) are the expanded uncertainties with 0.95 level of confidence of the
D
a
20.08 24.41 29.66 35.58 15.85 19.63 24.42 29.75 36.32 3.00 4.02 4.89 6.14 6.82 8.32 9.60 11.65 20.66 23.51 29.71 36.57
MA
0.0300
343.15 348.15 353.15 358.15 333.15 338.15 343.15 348.15 353.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 338.15 343.15 348.15 353.15
PT E
experimental temperature T, the experimental pressure Pexp, and the experimental solute mass fraction W1,exp, respectively. W1,cal is the calculated mass fraction by lever ruler of the solute.
AC
CE
RD (W1) is the relative deviations between W1,exp and W1,cal.
28
MA
NU
SC
RI
PT
ACCEPTED MANUSCRIPT
D
Fig. 1. Experimental apparatus for the measurement of vapor pressure.
PT E
1, intelligent temperature controller; 2, constant temperature bath glass sink; 3, U-type equilibrium still; 4, condenser; 5, thermocouple thermometer; 6, buffer air tank; 7, vent value;
AC
pump.
CE
8, needle value; 9, precision digital pressure gauge; 10, pressure buffer tank; 11, vacuum
29
ACCEPTED MANUSCRIPT
60
323.2 K 333.2 K
328.2 K 338.2 K
50
343.2 K 353.2 K
348.2 K 358.2 K
P/kPa
40
PT
solid lines P(UNIFAC) dashed lines P(COSMO)
RI
dash doted lines P(H2O)
SC
30
NU
20
0 0.0
MA
10
0.2
0.4
0.6
0.8
1.0
PT E
D
x1
Fig. 2. Vapor pressures of binary mixtures {water (1) + [EMIM][Tf2N] (2)} at different
CE
temperatures. Scattered points, experimental data; solid lines, predicted by the UNIFAC-Lei
AC
model; dashed lines, predicted by the COSMO-RS model; dash doted lines, vapor pressures of pure water.
30
ACCEPTED MANUSCRIPT
323.15 K 333.15 K 343.15 K 353.15 K
0.035
0.025 0.020 0.015
PT
wH2O in ZIF-7
0.030
328.15 K 338.15 K 348.15 K 358.15 K
0.010
(a)
20
30
40
0.14
323.15 K 333.15 K 343.15 K 353.15 K
MA
0.12
328.15 K 338.15 K 348.15 K 358.15 K
0.08
D
0.06 0.04 0.02
10
20
(b) 30
40
50
60
P/kPa
AC
CE
0
PT E
wH2O in ZIF-8
0.10
0.00
60
NU
P/kPa
50
SC
10
RI
0.005
Fig. 3. Adsorption amount of H2O in ZIF-7/ZIF-8 calculated by GCMC simulation. (a). ZIF-7; (b). ZIF-8.
31
PT
ACCEPTED MANUSCRIPT
(b)
MA
NU
SC
RI
(a)
(d)
PT E
D
(c)
CE
Fig. 4. Center-of-mass distribution of H2O in ZIF-8 at 323.15 K and different pressures. The red, green, blue, gray, and white colors represent the H2O molecule, Zn, N, C, and H atoms,
AC
respectively. (a) 15.97 kPa; (b) 25.28 kPa; (c) 38.73 kPa; (d) 57.65 kPa.
32
ACCEPTED MANUSCRIPT
0.04
(a) no error line
0.02
PT
W1,cal
0.03
±10% error lines
0.01
0.02
0.03
SC
0.00 0.00
RI
0.01
0.04
0.04
NU
W1,exp
(b)
MA
no error line
0.02
PT E
0.01
D
W1,cal
0.03
0.01
0.02
CE
0.00 0.00
±10% error lines
0.03
0.04
AC
W1,exp
Fig. 5. Comparison between calculated solubility (W1,cal) and experimental data (W1,exp) with the content of ZIF-7/ZIF-8 ranging from 0.005-0.05 (on H2O-free basis) for the ternary systems. (a). {water (1) + [EMIM][Tf2N] (2) + ZIF-7 (3)}; (b). {water (1) + [EMIM][Tf2N] (2) + ZIF-8 (3)}.
33
ACCEPTED MANUSCRIPT
60
x'1=0.0993 x'1=0.1806 x'1=0.3082
50
x'1=0.4030 pure water solid line: UNIFAC
30
PT
P/kPa
40
10 330
335
340
345
350
355
(a)
360
SC
325
RI
20
60
x'1=0.1822 x'1=0.3104 x'1=0.4055
50
pure water solid line: UNIFAC
30
PT E
20
D
P/kPa
40
MA
x'1=0.4789
NU
T/K
10
330
335
340
345
350
355
360
T/K
AC
CE
325
(b)
Fig. 6. Vapor pressure versus temperature for {water (1) + [EMIM][Tf2N] (2) + ZIF-7 (3)}. (a). W3 = 0.005; (b). W3 = 0.015. Solid lines, calculated by the UNIFAC-Lei model on ZIF-7-free basis; scattered points, experimental data.
34
ACCEPTED MANUSCRIPT
x'1=0.0993
60
x'1=0.1814 x'1=0.3103
P/kPa
50 40
pure water solid line: UNIFAC
30
PT
20 10
325
330
335
340
345
x'1=0.1822 x'1=0.3104
50
x'1=0.4047
MA
30
PT E
20 10
325
(b)
330
335
340
345
350
355
360
T/K
AC
CE
0 320
360
D
P/kPa
pure water solid line: UNIFAC 40
355
NU
60
350
SC
T/K
RI
(a)
0 320
Fig. 7. Vapor pressure versus temperature for {water (1) + [EMIM][Tf2N] (2) + ZIF-8 (3)}. (a). W3 = 0.005; (b). W3 = 0.015. Solid lines, calculated by the UNIFAC-Lei model on ZIF-8-free basis; scattered points, experimental data.
35
ACCEPTED MANUSCRIPT Highlights ► Vapor pressures of water + [EMIM][Tf2N] were measured and predicted by the UNIFAC-Lei model; ► The adsorption amount of H2O in [EMIM][Tf2N] + ZIF-7/ZIF-8 mixture was measured
PT
and predicted by the lever rule;
RI
► This work provides the basic thermodynamic data for adsorptive absorption– a new unit
AC
CE
PT E
D
MA
NU
SC
operation in chemical engineering.
36