- Email: [email protected]
Evaluation of thermodynamic behavior of Bisphenol A in water with deep eutectic solvents
South African Journal of Chemical Engineering 27 (2019) 53–59
Contents lists available at ScienceDirect
South African Journal of Chemical Engineering journal homepage: www.elsevier.com/locate/sajce
Evaluation of thermodynamic behavior of Bisphenol A in water with deep eutectic solvents
T
K. Ashwinia, R.S. Achsaha, M. Danish John Paula, R. Anantharaja,∗, K. Sarath Kumarb, P. Rajamanib, D. Duraimuruganb a b
Department of Chemical Engineering, SSN College of Engineering, Kalavakkam, Chennai, 603110, Tamilnadu, India Department of Chemical Engineering, Mohamed Sathak Engineering College, Kilakarai, 623806, India
A R T I C LE I N FO
A B S T R A C T
Keywords: Bisphenol A Deep eutectic solvent Thermodynamic property Extraction process
Density of aqueous Bisphenol A (BPA) solution, tetra-butyl ammonium bromide-glycerol as DES1 and their mixture were measured at different temperatures from 293.15 to 343.15 K with an interval of 5 K. From this measured densities, the solution thermodynamic properties such as excess molar volume, partial molar volume, apparent molar volume and isothermal expansivity of the mixture of aqueous BPA at different ppm (5, 10, 15, 20 and 25 ppm) with DES1 were calculated. Further, tetrabutyl ammonium bromide-decanoic acid as DES2 used as potential solvent for the removal of BPA from their aqueous solution. In this regard, aqueous solution pH were measured in order to understand the mobility of ions and strength of Hydrogen atom in the aqueous solution. Finally, solvent based extraction process characterized in terms of distribution ratio and efficiency.
1. Introduction EDCs have been found in almost all water matrices including treated and untreated wastewater, ground water, surface water and drinking water (i.e. bottle water and domestic household tap water). Wastewater treatment plant is the major source of EDCs emission into water bodies (BenFredj et al., 2015). In addition, wildlife in area close to treated wastewater discharge point and sewage treatment plants are also affected by exposure to EDCs via hormonal changes including a wide range of diseases and disabilities, diabetes, cancer, heart disease, reproductive health problems, neurodevelopmental and neurodegenerative disorders (Wang et al., 2012). There are many chemicals suspected of acting as endocrine disruptors have grown significantly in the past decade. Typical EDCs are natural androgens, natural estrogens, artificial synthetic androgens, artificial synthetic estrogens, phytoestrogens, plastics, pesticides, insecticides, fungicides, PCBc, PBBs, pharmaceutical agents as well as other industrial compounds. Among this large group of EDCs in origin; estrogens, plastics, pesticides and pharmaceutical agent are reported as highly endocrine disrupting potency by Environmental Protection agency in U.S and European Union Priority Substances (Wang et al., 2012; Basile et al., 2011). For example; estrogen based EDCs are estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ehinylestradiol (EE2). Bisphenol A is an example for plastics, diethylstilbestrol (DES) for
∗
pharmaceutical agents and dichlorodiphenyltrichloroethane (DDT) for pesticides. Because, these group of EDCs have extensive distribution in aqueousuatic environment after treatment also. Since EDCs concentration are extremely low in environment and water matrices, likely at parts-per-trillion (i.e. ng.L−1) levels. So far there are many conventional method used to remove EDCs chemicals in water and wastewater treatment plant such as adsorption using activated carbon, advanced oxidation process (i.e. ozonation and non-thermal plasma), biodegradation process, and membrane separation process including reverse osmosis (RO), nanofiltration (NF), microfiltration (MF), and ultrafiltration (UF). These conventional methods have several major drawbacks such as: a). operational condition should be strictly controlled, b). large amount of adsorbent is required in full scale plants, c). the effect of oxidation products are still not fully understood, d). Limited performance due to pore size by the membrane techniques, e). Chemical fouling and biofouling in the membrane techniques (BenFredj et al., 2015). Moreover, these methods are not effective for considering their very low concentrations in wastewater/ water bodies (Muz et al., 2012). The solvent extraction becomes a very interesting alternative method due to an easy, cheap, facile operation, very efficient and economically viable (Cabo et al., 2012). On the other hand the choice of suitable solvent is a crucial step in the development of solvent extraction method for Lab scale and large scale applications. In recent years, green solvent like deep eutectic solvent (DES)
Corresponding author. E-mail address: [email protected] (R. Anantharaj).
https://doi.org/10.1016/j.sajce.2018.12.003 Received 6 September 2018; Received in revised form 24 November 2018; Accepted 18 December 2018 1026-9185/ © 2018 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).
South African Journal of Chemical Engineering 27 (2019) 53–59
K. Ashwini et al.
with the interval of 5 K and the samples were also subjected for quantitative analysis using UV spectrometer JASCO V-630 to find the concentration of BPA at 275 nm. Anton Paar DMA 4500 M density meter was used to measure the densities of the samples. The density meter was calibrated using ultrapure water and the uncertainty was +/0.00002 g/cm3.
provide an important alternative in catalysis, organic synthesis, material preparation, electrochemistry, substance dissolution, separation process (Green Chem. et al., 2013). DES is attractive solvent in separation of EDCs from water and wastewater treatment plant and are competitive with respect to molecular solvent and ionic liquids. DES is an environmentally benign and designable, non-volatile, non-flammable, highly solvating and non-coordinating media having a high thermal stability over a wide liquid range, have higher aromatic and hetero aromatic extracting ability and are virtually immiscible with water, preventing cross contamination, and recovery and regeneration involves simple heating to recover the EDCs. Furthermore, DES can accept or donate electrons or protons to form hydrogen bond, hetero atom–H bond interaction, CH–π interaction, π–π interaction, chargecharge interaction and orbital level interaction. Therefore, they may have good solvent selectivity, solvent capacity and performance index for EDCs than organic solvent and ionic liquids. Thus, we have paid great attention in removal of EDCs by solvent extraction (SE) process using DES's. In this study, density of 5, 10, 15, 20 and 25 ppm of BPA solution, tetra-butyl ammonium bromide-glycerol as DES1 and their mixture were measured at different temperatures from 293.15 to 343.15 K with an interval of 5 K. From this measured densities, the solution thermodynamic properties such as excess molar volume, partial molar volume, apparent molar volume and isothermal expansivity of the mixture of aqueous BPA and DES1 were calculated in order to understand their volumetric behaviour at different mole fraction of aqueous BPA with DES1. Further, tetrabutyl ammonium bromide-decanoic acid as DES2 was used as potential solvent for the removal of BPA from their aqueous solution.
The aqueous BPA and DES1 were mixed to form the homogeneous system; the study of the thermodynamic property based on density of the system is measured for the mole fraction from 0 to 1 with the interval of 0.1 mole fraction. The thermodynamic studies lead to understand the behavior of the molecules and interaction between BPA and solvent. The aqueous BPA and DES1 system was analyzed for various temperature ranges in 293.15 K–343.15 K with 5 K of temperature interval. The individual densities of the aqueous BPA for 5 ppm, 10 ppm, 15 ppm, 20 ppm, 25 ppm and DES1 were measured and studied, the densities of the pure samples and binary mixtures are tabulated in Table 1. The densities were measured for entire mole fraction from 0 to 1 and temperature from 293.15 K to 343.15 K with 5 K interval. With increase in temperature the decrease in density of the mixtures decreased, since the kinetic energy of the constituent molecules becomes higher. Isothermal expansivity is the thermodynamic property, used to understand the binary mixtures behaviors with respect to temperature. The isothermal expansivity can be calculated by using the equation;
2. Experimental
α=
2.1. Chemicals
Isothermal expansivity of aqueous BPA- DES1 are tabulated for 293.15 K–343.15 K with the interval of 5 K and given in Table 2. Excess isothermal expansivity,
3. Results and discussion 3.1. Thermodynamic properties
Targeted EDC compound Bisphenol A (BPA) was purchased from Sigma-Aldrich. Tetrabutylammonium bromide salt was obtained from Sigma-Aldrich, Deconic acid from Alfa Aesar and glycerol was purchased from Fisher Scientific. The purity of the all chemicals is more than or equal to 99%, further no additional purification step was done in the purchased chemicals.
∂ ln ρ ⎞ 1 ⎛ ∂V ⎞ = −⎛ V ⎝ ∂T ⎠P ⎝ ∂T ⎠P
α E = αmix − (ϕ1 α1) − (ϕ2 α2)
(2)
x1 v1 ⎞ ϕ1 = ⎛ ⎝ x1 v1 + x2 ⎠
(3)
x2 v2 ⎞ ϕ2 = ⎛ ⎝ x1 v1 + x2 ⎠
(4)
⎜
2.2. Procedure
(1)
⎟
⎜
⎟
α1, α2 and αmix are the thermal expansion coefficient of component 1,2 and mixture, φ1 and φ2 are the volume fractions of component 1 and 2 of the mixtures, x1 and x2 are the mole fractions and Vm,1 and Vm,2 are molar volumes of component 1 and 2 respectively. The values of isothermal expansivity and excess isothermal
The pure water was (deionized water) used to prepare stock solution of BPA and also various concentrations of BPA of 5 ppm, 10 ppm, 15 ppm, 20 ppm and 25 ppm. 100 mg/L stock solution of BPA in water was prepared by dissolving 50 mg of BPA in 500 mL of water. Using the dilution method, BPA of 5 ppm, 10 ppm, 15 ppm, 20 ppm and 25 ppm were prepared. The hydrophilic deep eutectic solvent (DES1), Tetrabutylammonium bromide salt and glycerol was prepared in 1:2 ratios respectively. The mixture was completely dissolved to form solution and was further used for the experiment. Various compositions of mixtures of aqueous BPA and hydrophilic DES1 from 0 to 1 with the interval of 0.1 fraction was prepared. The samples are well mixed in the rotary shaker for 6 h’ time duration and the mixture was allowed to attain equilibrium condition. The density of each sample was measured for temperatures from 293.15 K to 343.15 K at the interval of 5 K. The hydrophobic DES2 (Tetrabutyl ammonium bromide + Decanoic acid) was prepared, the aqueous BPA and DES2 was taken for 0.4, 0.5 and 0.6 mole fractions of aqueous BPA and the samples was kept in the rotary shaker for 6 h of mixing and then allowed to rest to attain equilibrium condition. Since the DES2 was hydrophobic in nature, the samples where observed with heterogeneous layer. The aqueous and DES layers were separated from the samples for analysis of BPA concentrations in both the layers. After the separation the two individual layers density is measured in different temperatures 293.15 K–343.15 K
Table 1 Density of pure component for varies temperature. T (K)
Density (g/cm3)
TBAB + Glycerol
Aqueous Bisphenol A solution
293.15 298.15 303.15 308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15
54
5ppm
10 ppm
15 ppm
20 ppm
25 ppm
DES
0.9988 0.9976 0.9962 0.9946 0.9928 0.9908 0.9886 0.9863 0.9829 0.9800 0.9781
0.9988 0.9977 0.9963 0.9946 0.9928 0.9908 0.9887 0.9863 0.9837 0.9807 0.9784
0.9988 0.9976 0.9962 0.9946 0.9928 0.9908 0.9886 0.9863 0.9838 0.9811 0.9784
0.9988 0.9976 0.9962 0.9946 0.9928 0.9908 0.9886 0.9863 0.9838 0.9812 0.9781
0.9987 0.9976 0.9962 0.9946 0.9927 0.9907 0.9886 0.9862 0.9836 0.9809 0.9769
1.1795 1.1763 1.1730 1.1697 1.1664 1.1629 1.1596 1.1562 1.1528 1.1494 1.1459
South African Journal of Chemical Engineering 27 (2019) 53–59
K. Ashwini et al.
Table 2 Thermal expansivity for pure solution. T (K)
V20 =
Aqueous BPA solution
293.15 298.15 303.15 308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15
TBAB + Glycerol
25 ppm
20 ppm
15 ppm
10 ppm
5ppm
α*10−4 (K−1)
α*10−4 (K−1)
α*10−4 (K−1)
α*10−4 (K−1)
α*10−4 (K−1)
α*10−4 (K−1)
4.0051 4.0097 4.0153 4.0219 4.0293 4.0374 4.0463 4.0560 4.0666 4.0778 4.0942
4.0049 4.0095 4.0151 4.0216 4.0290 4.0371 4.0460 4.0557 4.0659 4.0768 4.0895
4.0049 4.0095 4.0151 4.0216 4.0290 4.0371 4.0460 4.0556 4.0659 4.0770 4.0884
4.0048 4.0094 4.0150 4.0216 4.0289 4.0371 4.0459 4.0555 4.0664 4.0786 4.0882
4.0049 4.0095 4.0152 4.0217 4.0290 4.0372 4.0461 4.0557 4.0698 4.0816 4.0897
5.9345 5.9508 5.9675 5.9844 6.0016 6.0190 6.0365 6.0542 6.0721 6.0901 6.1084
x1 M1 ρ1
(6)
Molar Volume of mixture,
Vmixture or Vm =
x1 M1 + x2 M2 ρmixture
(7)
Where; x1 and x2 are mole fraction of component 1 and 2, M1 and M2 are molecular weight of component 1 and 2, ρ1- density of component 1, ρ2 - density of component 2, ρmix - density of mixture, respectively. The above equation was used to calculate the molar volume of mixture and pure components for 5 ppm, 10 ppm, 15 ppm, 20 ppm and 25 ppm concentrations of aqueous BPA and DES1 mixtures. Excess molar volume property of mixture can be used to characterize the non-ideal behavior of the mixture. The excess molar volume can be calculated using the following equation.
expansivity are tabulated in Table 2 and Fig. 1. The values of isothermal expansivity tends to increase with increase in temperature for all the mole fractions and various concentrations. The isothermal expansivity values of aqueous BPA increased with increase in concentration of BPA, DES1 had higher isothermal expansivity value compared to BPA. It can also be observed that with increase in the composition of aqueous BPA in the mixture the isothermal expansivity value tends to decrease. The isothermal expansivity value range from 4.09 × 10−4 to 6.23 × 10−4 K−1. The values of isothermal expansivity indirectly reflect the interaction between the molecules of the mixtures. The observed positive values of excess isothermal expansivities for this mixture system signifies the temperature dependence of interactions between unlike interactions is more necessary than like-like interactions in presence of great quantities of DES (Anouti et al., 2009). The α E value is maximum in the mole fractions 0.4 and 0.6 of aqueous BPA with the range of 1.15 × 10−4 to 1.27 × 10−4 with increase in temperature. The pure component and binary mixture molar volume can be calculated by using the following equation (Centers for Disease Control and Prevention (CDC), 2009). Molar volume of component 1 and 2,
V10 =
x2 M2 ρ2
VmE = Vmixture − x1 V10 − x2 V20
(8)
x M + x2 M2 ⎤ ⎡ x1 M1 xM VmE = ⎡ 1 1 − + 2 2⎤ ⎢ ρ ⎥ ⎢ ρ ρ2 ⎥ mixture ⎦ ⎣ ⎦ ⎣ 1
(9)
Fig. 2 shows that excess molar volume has positive values for all concentrations which indicated that the dispersive interaction between mixture components. This interaction arises due to the breaking of cohesive forces acting with in like molecules as increase the excess molar volume. The highest positive excess molar volume at the mole fraction 0.5 of aqueous BPA denotes the breaking up of hydrogen bond in the binary mixtures is maximum in the composition (Bisphenol, 2014). This trend is observed in various temperatures with respect to mole fraction and the values of VE increases slightly with increase in temperature. Also the positive contribution of excess molar volume denotes the occurrence of physical interaction which consists of dispersion forces or weak dipole-dipole interaction. The temperature effect on the excess molar volume is due to the increase in kinetic energy which does not change the interaction of hydrogen bonds. It can be seen that sign and magnitude of excess molar volume gives a good estimate of unlike interactions in the binary mixtures (Bisphenol, 2014). Here, the mixtures of aqueous BPA+ DES1 leads to volume increase owing to increase in repulsive interactions or the replacement of short range by long range intermolecular interactions (Wankhede et al., 2006). The partial molar volume can be calculated by the following equation (Bisphenol, 2014). Partial molar volume of component 1;
(5)
Fig. 1. The Excess isothermal Expansivity. 55
South African Journal of Chemical Engineering 27 (2019) 53–59
K. Ashwini et al.
Fig. 2. Excess molar volume vs. mole fraction. E
∂V − V1 = VmE + V10 + x2 ⎛⎜ m ⎞⎟ ⎝ ∂x1 ⎠P, T
following equation: Excess Partial molar volume of component 1;
(10)
− − V1E = V1 − V10
Partial molar volume of component 2; E
∂V − V2 = VmE + V20 − x1 ⎛⎜ m ⎞⎟ ⎝ ∂x1 ⎠P, T
(12)
Excess Partial molar volume of component 2; (11)
− − V2E = V2 − V20
The values of V1 with respect to component 2 of the mixture, the peak value is found in the mole fraction 0.8 of component 1 and V2 has a peak value at 0.3 value of x1 and again with increase of composition in the mixture the values decreases. This shows that beyond the peak values there is accommodation of constituent molecules of the mixture within each other. From Fig. 3, the partial molar volume increases with increase in temperature for various concentrations. The value of partial molar volume is in the range of 230–240 cm3mol-1 which indicates that the solute-solvent interactions is very high in this system and the temperature does not play a significant role in this system which states that there is no much correlation between the temperature and solution interactions (Omrani et al., 2010). Excess partial molar volume is characterized for the non-ideal behavior of the mixtures. The excess partial molar volume can be obtained for the aqueous. BPA+DES1 mixture system interaction using the
(13)
It can be seen that excess partial molar volume has positive values for all temperatures and various mole fractions which shows that weaker solute-solvent interactions of mixture have taken place (Anouti et al., 2009). At the equimolar ratio the values of V1E and V2E are maximum which shows that the positive interactions are maximum at this point (Figs. 4 and 5 and Supporting Tables 1.1–1.5). The apparent molar property of a binary mixture contributes the non-ideality of each component in the mixture. Its shows the changes in the corresponding solution properties, when a component is added to the solution. It is described as apparent because it appears to be the molar property of a component in a binary mixture. The apparent molar volume of the binary system can be calculated as using the following equation, Apparent Molar volume of component 1,
Fig. 3. Partial molar volume at 298.15 K. 56
South African Journal of Chemical Engineering 27 (2019) 53–59
K. Ashwini et al.
Fig. 4. Excess partial molar volume of aq.BPA at 298.15 K.
VE Vφ,1 = ⎡V10 − m ⎤ ⎢ x1 ⎥ ⎣ ⎦
BPA and DES1 for temperatures from 293.15 K to 343.15 K with 5 K interval describes that aqueous BPA and DES have high molecular interactions in the range of 0.4, 0.5 and 0.6 mole fraction at ambient conditions so this range of aqueous BPA was chosen for the extraction studies of BPA from aqueous medium. The extraction process used had change in hydrogen bond donor in deep eutectic solvent with decanoic acid due to its hydrophobic nature. The aqueous BPA and DES2 (tetrabutyl ammonium bromide + decanoic acid) mixture formed heterogeneous system was favorable for the extraction process.
(14)
Apparent Molar volume of component 2,
VE Vφ,2 = ⎡V20 − m ⎤ ⎢ x2 ⎥ ⎣ ⎦
(15)
From Fig. 6, the apparent molar volume can be interpreted in terms of solute-solute interactions. The parameter apparent molar volume is the volumetric coefficient that characterizes the pairwise interaction of solvated solute species in binary mixtures. The sign of apparent molar volume indicates the nature of the interaction between the solute species. On the other hand, the overlap of two hydrophobic hydration cospheres when a polar group interacts leads to a negative volume change, and hence a negative sign of apparent molar volume. The V∅ ,1 values follow a linear trend and ascends from negative to positive values with the increase in composition of aqueous BPA in the mixture and V∅ ,2 also follows the same trends as aqueous BPA, with increase in the composition of DES1 the values moves from negative to positive interactions. The study on thermodynamic properties such as excess molar volume, partial molar volume, excess partial molar volume, apparent molar volume and isothermal expansivity for the mixture of aqueous
3.2. Extraction of BPA Extraction is carried out at room temperature, due to limited solubility of BPA in water, a known amount of BPA was dissolved in deionized water to prepare aqueous BPA concentrations 5, 10, 15, 20 and 25 ppm (Omrani et al., 2010; Fan et al., 2008). The aqueous and the DES layer were separated and analyzed for the BPA concentrations at 275 nm. The concentration values of BPA in both the layer were collected and was used to calculate the parameters of extraction such as distribution ratio and percentage of extraction. The distribution ratio of the BPA between DES2 (tetrabutyl ammonium bromide + decanoic acid) and aqueous layer can be calculated by the following equation
Fig. 5. Excess partial molar volume of DES (TBAB- Glycerol) at 298.15 K 57
South African Journal of Chemical Engineering 27 (2019) 53–59
K. Ashwini et al.
Fig. 6. Apparent molar volumes for binary mixture at 298.15 K.
D=
CDES CAq
liquid (LLE) extraction process, the highest extraction efficiency of 98% was achieved using DES2 as extraction solvent media.
(16)
From Table 3, the distribution ratio increased with the increase in concentration of aqueous BPA, and also with increase in the composition of aqueous BPA in the mixture. Distribution ratio also increases with the hydrogen bond interaction of BPA with DES2. The distribution ratio study suggests that hydrogen bonding and hydrophobic behavior of the DES and BPA leads to the extraction of higher quantity of BPA from aqueous rich phase to DES2 rich phase. The extraction efficiency is known for the efficient separation of BPA from aqueous solution using DES solvent. The extraction is carried out to separate the BPA from the aqueous solution and the difference in the concentration is calculated. The ratio between concentrations of BPA in DES2 (CDES) to total concentration of the BPA in the mixture system (CDES + CAqueous) is predicted. The following equation used to find out the percentage extraction of BPA in aqueous solution.
E=
CDES × 100 (CDES + CAq )
4. Conclusion The density of the mixture of aqueous BPA with DES1 decreased with the decrease in mole fraction of the DES1. This experimental data could be used in future to evaluate the kinetic parameters and industrial application. The LLE method was studied for the extraction of BPA from their solution using DES2. The mixture of aqueous BPA + DES2 (tetrabutylammonium bromide + decanoic acid) formed a heterogeneous mixture which favored the extraction, as BPA has hydrophobic nature which lead to the extraction of BPA from aqueous phase to hydrophobic DES2 rich phase. From the experimental data, the distribution ratio and extraction efficiency were calculated. It was found that the distribution ratio of BPA increased with increase in composition of DES2 in the mixture and the extraction efficiency was achieved very high with in the range of 80–99%. The hydrogen bonding and hydrophobic interaction between DES2 and the BPA played an important role in the extraction technique. It could be conclude that the deep eutectic solvents can be used as potential solvent for the removal of BPA from water matrices.
(17)
The results are given in Table 3 and the extraction efficiency can be interpreted by an increase of hydrogen bonding interaction between BPA compound in aqueous solution and the DES to achieve the efficiency, where they have greater distribution ratio to achieve the higher extraction efficiency, this study suggests that the decrease in hydrogen bonding interaction between the BPA and DES probably the extraction efficiency of BPA were decreased (Omrani et al., 2010). There are two phenolic hydroxyls and two aromatic rings present in the BPA molecules, so stronger interaction has occurred with hydrophobic DES2. The extraction also depends on the pH of the aqueous phase of the extraction process. The maximum removal of BPA from aqueous phase can be obtained in acidic pH (Omrani et al., 2010; Fan et al., 2008; Zhong et al., 2007). The pH of the aqueous BPA ranged from 2.0 to 2.5. The percentage of extraction have also increased with the increase in the composition of aqueous BPA. The extraction percentage ranged from 80 to 99% for various concentrations of aqueous BPA. From the liquid-
Conflicts of interest I am sure that there is no conflict in any manner in this manuscript including data and text, etc.
Acknowledgement The financial support from Science and Engineering Research Board – DST (YSS/2015/001546), India & SSN Trust, Chennai, Tamil Nadu, is gratefully acknowledged.
Table 3 Distribution ratio and Extraction efficiency at varies concentration. Concentration of BPA solution (ppm)
5
X (mole fraction of aqueous solution) pH Distribution ratio Extraction efficiency %
0.4 2.08 8.05 88.95
10 0.5 2.32 8.75 89.74
0.6 2.34 9.41 90.39
0.4 2.11 11.93 92.27
15 0.5 2.27 6.31 86.32
0.6 2.28 19.99 95.24
58
0.4 2.1 3.97 79.9
20 0.5 2.22 42.54 97.7
0.6 2.32 33.67 97.12
0.4 2.16 11.79 92.18
25 0.5 2.18 5.48 84.58
0.6 2.33 18.58 94.89
0.4 2.06 5.59 84.82
0.5 2.18 16.9 94.41
0.6 2.32 82.39 98.8
South African Journal of Chemical Engineering 27 (2019) 53–59
K. Ashwini et al.
Appendix A. Supplementary data
Chemicals, Executive Summary. Atlanta, GA. http://www.cdc.gov/exposurereport/. Fan, Jing, Fan, Yunchang, Pei, Yuanchao, KunWua, Wang, Jianji, Fan, Maohong, 2008. Solvent extraction of selected endocrine-disrupting phenols using ionic liquids. Separ. Purif. Technol. 61, 324–331. Green Chem. 15, 2793–2795. Muz, M., Sonmez, S., Komesli, O.T., Bakrdere, S., Gokcay, C.F., 2012. Analyst 137, 884–889. Omrani, Abdollah, Rostami, Abbas Ali, Mokhtary, Maryam, 2010. Densities and volumetric properties of 1,4-dioxane with ethanol, 3-methyl-1-butanol, 3-amino-1-propanol and 2-propanol binary mixtures at various temperatures. J. Mol. Liq. 157, 18–24. Wang, G., Ma, P., Zhang, Q., Lewis, J., Lacy, M., Furukawa, Y., Reilly, S.E.O., Meaux, S., McLachlan, J., Zhang, S., 2012. J. Envion. Monit 14 1353-1353. Wankhede, N.N., Wankhede, D.S., Lande, M.K., Arbad, B.R., 2006. Molecular interactions in (2, 4,6-trimethyl-1,3,5-trioxane + n-alkyl acetates) at T = (298.15, 303.15, and 308.15) K. J. Chem. Thermodyn. 38, 1664–1668. Zhong, Yanwei, Wang, Haiju, Diao, Kaishen, 2007. Densities and excess volumes of binary mixtures of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate with aromatic compound at T=(293.15 to 313.15) K. J. Chem. Thermodyn. 39, 291–296.
Supplementary data to this article can be found online at https:// doi.org/10.1016/j.sajce.2018.12.003. References Anouti, Meriem, Caillon-Caravanier, Magaly, Dridi, Yosra, Jacquemin, Johan, Hardacre, Christopher, Lemordant, Daniel, 2009. Liquid densities, heat capacities, refractive index and excess quantities for {protic ionic liquids+ water} binary system. J. Chem. Thermodyn. 41, 799–808. Basile, T., Petrella, A., Petrella, M., Boghetich, G., Petruzzelli, V., Colasuonno, S., Petruzzelli, D., 2011. Ind. Eng. Chem. Res. 50, 8389–8401. BenFredj, S., Nobbs, J., Tizaoui, C., Monser, L., 2015. Chem. Eng. J. 262, 417–426. Bisphenol, A.(B.P.A.), 2014. World Market Outlook and Forecast up to 2018. Cabo, B.R., Francisco, M., Soto, A., Arce, A., 2012. Fluid Phase Equil. 314, 107–112. Centers for Disease Control and Prevention (CDC), 2009. National Center for Environmental Health, Fourth National Report on Human Exposure to Environmental
59
Contents lists available at ScienceDirect
South African Journal of Chemical Engineering journal homepage: www.elsevier.com/locate/sajce
Evaluation of thermodynamic behavior of Bisphenol A in water with deep eutectic solvents
T
K. Ashwinia, R.S. Achsaha, M. Danish John Paula, R. Anantharaja,∗, K. Sarath Kumarb, P. Rajamanib, D. Duraimuruganb a b
Department of Chemical Engineering, SSN College of Engineering, Kalavakkam, Chennai, 603110, Tamilnadu, India Department of Chemical Engineering, Mohamed Sathak Engineering College, Kilakarai, 623806, India
A R T I C LE I N FO
A B S T R A C T
Keywords: Bisphenol A Deep eutectic solvent Thermodynamic property Extraction process
Density of aqueous Bisphenol A (BPA) solution, tetra-butyl ammonium bromide-glycerol as DES1 and their mixture were measured at different temperatures from 293.15 to 343.15 K with an interval of 5 K. From this measured densities, the solution thermodynamic properties such as excess molar volume, partial molar volume, apparent molar volume and isothermal expansivity of the mixture of aqueous BPA at different ppm (5, 10, 15, 20 and 25 ppm) with DES1 were calculated. Further, tetrabutyl ammonium bromide-decanoic acid as DES2 used as potential solvent for the removal of BPA from their aqueous solution. In this regard, aqueous solution pH were measured in order to understand the mobility of ions and strength of Hydrogen atom in the aqueous solution. Finally, solvent based extraction process characterized in terms of distribution ratio and efficiency.
1. Introduction EDCs have been found in almost all water matrices including treated and untreated wastewater, ground water, surface water and drinking water (i.e. bottle water and domestic household tap water). Wastewater treatment plant is the major source of EDCs emission into water bodies (BenFredj et al., 2015). In addition, wildlife in area close to treated wastewater discharge point and sewage treatment plants are also affected by exposure to EDCs via hormonal changes including a wide range of diseases and disabilities, diabetes, cancer, heart disease, reproductive health problems, neurodevelopmental and neurodegenerative disorders (Wang et al., 2012). There are many chemicals suspected of acting as endocrine disruptors have grown significantly in the past decade. Typical EDCs are natural androgens, natural estrogens, artificial synthetic androgens, artificial synthetic estrogens, phytoestrogens, plastics, pesticides, insecticides, fungicides, PCBc, PBBs, pharmaceutical agents as well as other industrial compounds. Among this large group of EDCs in origin; estrogens, plastics, pesticides and pharmaceutical agent are reported as highly endocrine disrupting potency by Environmental Protection agency in U.S and European Union Priority Substances (Wang et al., 2012; Basile et al., 2011). For example; estrogen based EDCs are estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ehinylestradiol (EE2). Bisphenol A is an example for plastics, diethylstilbestrol (DES) for
∗
pharmaceutical agents and dichlorodiphenyltrichloroethane (DDT) for pesticides. Because, these group of EDCs have extensive distribution in aqueousuatic environment after treatment also. Since EDCs concentration are extremely low in environment and water matrices, likely at parts-per-trillion (i.e. ng.L−1) levels. So far there are many conventional method used to remove EDCs chemicals in water and wastewater treatment plant such as adsorption using activated carbon, advanced oxidation process (i.e. ozonation and non-thermal plasma), biodegradation process, and membrane separation process including reverse osmosis (RO), nanofiltration (NF), microfiltration (MF), and ultrafiltration (UF). These conventional methods have several major drawbacks such as: a). operational condition should be strictly controlled, b). large amount of adsorbent is required in full scale plants, c). the effect of oxidation products are still not fully understood, d). Limited performance due to pore size by the membrane techniques, e). Chemical fouling and biofouling in the membrane techniques (BenFredj et al., 2015). Moreover, these methods are not effective for considering their very low concentrations in wastewater/ water bodies (Muz et al., 2012). The solvent extraction becomes a very interesting alternative method due to an easy, cheap, facile operation, very efficient and economically viable (Cabo et al., 2012). On the other hand the choice of suitable solvent is a crucial step in the development of solvent extraction method for Lab scale and large scale applications. In recent years, green solvent like deep eutectic solvent (DES)
Corresponding author. E-mail address: [email protected] (R. Anantharaj).
https://doi.org/10.1016/j.sajce.2018.12.003 Received 6 September 2018; Received in revised form 24 November 2018; Accepted 18 December 2018 1026-9185/ © 2018 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).
South African Journal of Chemical Engineering 27 (2019) 53–59
K. Ashwini et al.
with the interval of 5 K and the samples were also subjected for quantitative analysis using UV spectrometer JASCO V-630 to find the concentration of BPA at 275 nm. Anton Paar DMA 4500 M density meter was used to measure the densities of the samples. The density meter was calibrated using ultrapure water and the uncertainty was +/0.00002 g/cm3.
provide an important alternative in catalysis, organic synthesis, material preparation, electrochemistry, substance dissolution, separation process (Green Chem. et al., 2013). DES is attractive solvent in separation of EDCs from water and wastewater treatment plant and are competitive with respect to molecular solvent and ionic liquids. DES is an environmentally benign and designable, non-volatile, non-flammable, highly solvating and non-coordinating media having a high thermal stability over a wide liquid range, have higher aromatic and hetero aromatic extracting ability and are virtually immiscible with water, preventing cross contamination, and recovery and regeneration involves simple heating to recover the EDCs. Furthermore, DES can accept or donate electrons or protons to form hydrogen bond, hetero atom–H bond interaction, CH–π interaction, π–π interaction, chargecharge interaction and orbital level interaction. Therefore, they may have good solvent selectivity, solvent capacity and performance index for EDCs than organic solvent and ionic liquids. Thus, we have paid great attention in removal of EDCs by solvent extraction (SE) process using DES's. In this study, density of 5, 10, 15, 20 and 25 ppm of BPA solution, tetra-butyl ammonium bromide-glycerol as DES1 and their mixture were measured at different temperatures from 293.15 to 343.15 K with an interval of 5 K. From this measured densities, the solution thermodynamic properties such as excess molar volume, partial molar volume, apparent molar volume and isothermal expansivity of the mixture of aqueous BPA and DES1 were calculated in order to understand their volumetric behaviour at different mole fraction of aqueous BPA with DES1. Further, tetrabutyl ammonium bromide-decanoic acid as DES2 was used as potential solvent for the removal of BPA from their aqueous solution.
The aqueous BPA and DES1 were mixed to form the homogeneous system; the study of the thermodynamic property based on density of the system is measured for the mole fraction from 0 to 1 with the interval of 0.1 mole fraction. The thermodynamic studies lead to understand the behavior of the molecules and interaction between BPA and solvent. The aqueous BPA and DES1 system was analyzed for various temperature ranges in 293.15 K–343.15 K with 5 K of temperature interval. The individual densities of the aqueous BPA for 5 ppm, 10 ppm, 15 ppm, 20 ppm, 25 ppm and DES1 were measured and studied, the densities of the pure samples and binary mixtures are tabulated in Table 1. The densities were measured for entire mole fraction from 0 to 1 and temperature from 293.15 K to 343.15 K with 5 K interval. With increase in temperature the decrease in density of the mixtures decreased, since the kinetic energy of the constituent molecules becomes higher. Isothermal expansivity is the thermodynamic property, used to understand the binary mixtures behaviors with respect to temperature. The isothermal expansivity can be calculated by using the equation;
2. Experimental
α=
2.1. Chemicals
Isothermal expansivity of aqueous BPA- DES1 are tabulated for 293.15 K–343.15 K with the interval of 5 K and given in Table 2. Excess isothermal expansivity,
3. Results and discussion 3.1. Thermodynamic properties
Targeted EDC compound Bisphenol A (BPA) was purchased from Sigma-Aldrich. Tetrabutylammonium bromide salt was obtained from Sigma-Aldrich, Deconic acid from Alfa Aesar and glycerol was purchased from Fisher Scientific. The purity of the all chemicals is more than or equal to 99%, further no additional purification step was done in the purchased chemicals.
∂ ln ρ ⎞ 1 ⎛ ∂V ⎞ = −⎛ V ⎝ ∂T ⎠P ⎝ ∂T ⎠P
α E = αmix − (ϕ1 α1) − (ϕ2 α2)
(2)
x1 v1 ⎞ ϕ1 = ⎛ ⎝ x1 v1 + x2 ⎠
(3)
x2 v2 ⎞ ϕ2 = ⎛ ⎝ x1 v1 + x2 ⎠
(4)
⎜
2.2. Procedure
(1)
⎟
⎜
⎟
α1, α2 and αmix are the thermal expansion coefficient of component 1,2 and mixture, φ1 and φ2 are the volume fractions of component 1 and 2 of the mixtures, x1 and x2 are the mole fractions and Vm,1 and Vm,2 are molar volumes of component 1 and 2 respectively. The values of isothermal expansivity and excess isothermal
The pure water was (deionized water) used to prepare stock solution of BPA and also various concentrations of BPA of 5 ppm, 10 ppm, 15 ppm, 20 ppm and 25 ppm. 100 mg/L stock solution of BPA in water was prepared by dissolving 50 mg of BPA in 500 mL of water. Using the dilution method, BPA of 5 ppm, 10 ppm, 15 ppm, 20 ppm and 25 ppm were prepared. The hydrophilic deep eutectic solvent (DES1), Tetrabutylammonium bromide salt and glycerol was prepared in 1:2 ratios respectively. The mixture was completely dissolved to form solution and was further used for the experiment. Various compositions of mixtures of aqueous BPA and hydrophilic DES1 from 0 to 1 with the interval of 0.1 fraction was prepared. The samples are well mixed in the rotary shaker for 6 h’ time duration and the mixture was allowed to attain equilibrium condition. The density of each sample was measured for temperatures from 293.15 K to 343.15 K at the interval of 5 K. The hydrophobic DES2 (Tetrabutyl ammonium bromide + Decanoic acid) was prepared, the aqueous BPA and DES2 was taken for 0.4, 0.5 and 0.6 mole fractions of aqueous BPA and the samples was kept in the rotary shaker for 6 h of mixing and then allowed to rest to attain equilibrium condition. Since the DES2 was hydrophobic in nature, the samples where observed with heterogeneous layer. The aqueous and DES layers were separated from the samples for analysis of BPA concentrations in both the layers. After the separation the two individual layers density is measured in different temperatures 293.15 K–343.15 K
Table 1 Density of pure component for varies temperature. T (K)
Density (g/cm3)
TBAB + Glycerol
Aqueous Bisphenol A solution
293.15 298.15 303.15 308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15
54
5ppm
10 ppm
15 ppm
20 ppm
25 ppm
DES
0.9988 0.9976 0.9962 0.9946 0.9928 0.9908 0.9886 0.9863 0.9829 0.9800 0.9781
0.9988 0.9977 0.9963 0.9946 0.9928 0.9908 0.9887 0.9863 0.9837 0.9807 0.9784
0.9988 0.9976 0.9962 0.9946 0.9928 0.9908 0.9886 0.9863 0.9838 0.9811 0.9784
0.9988 0.9976 0.9962 0.9946 0.9928 0.9908 0.9886 0.9863 0.9838 0.9812 0.9781
0.9987 0.9976 0.9962 0.9946 0.9927 0.9907 0.9886 0.9862 0.9836 0.9809 0.9769
1.1795 1.1763 1.1730 1.1697 1.1664 1.1629 1.1596 1.1562 1.1528 1.1494 1.1459
South African Journal of Chemical Engineering 27 (2019) 53–59
K. Ashwini et al.
Table 2 Thermal expansivity for pure solution. T (K)
V20 =
Aqueous BPA solution
293.15 298.15 303.15 308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15
TBAB + Glycerol
25 ppm
20 ppm
15 ppm
10 ppm
5ppm
α*10−4 (K−1)
α*10−4 (K−1)
α*10−4 (K−1)
α*10−4 (K−1)
α*10−4 (K−1)
α*10−4 (K−1)
4.0051 4.0097 4.0153 4.0219 4.0293 4.0374 4.0463 4.0560 4.0666 4.0778 4.0942
4.0049 4.0095 4.0151 4.0216 4.0290 4.0371 4.0460 4.0557 4.0659 4.0768 4.0895
4.0049 4.0095 4.0151 4.0216 4.0290 4.0371 4.0460 4.0556 4.0659 4.0770 4.0884
4.0048 4.0094 4.0150 4.0216 4.0289 4.0371 4.0459 4.0555 4.0664 4.0786 4.0882
4.0049 4.0095 4.0152 4.0217 4.0290 4.0372 4.0461 4.0557 4.0698 4.0816 4.0897
5.9345 5.9508 5.9675 5.9844 6.0016 6.0190 6.0365 6.0542 6.0721 6.0901 6.1084
x1 M1 ρ1
(6)
Molar Volume of mixture,
Vmixture or Vm =
x1 M1 + x2 M2 ρmixture
(7)
Where; x1 and x2 are mole fraction of component 1 and 2, M1 and M2 are molecular weight of component 1 and 2, ρ1- density of component 1, ρ2 - density of component 2, ρmix - density of mixture, respectively. The above equation was used to calculate the molar volume of mixture and pure components for 5 ppm, 10 ppm, 15 ppm, 20 ppm and 25 ppm concentrations of aqueous BPA and DES1 mixtures. Excess molar volume property of mixture can be used to characterize the non-ideal behavior of the mixture. The excess molar volume can be calculated using the following equation.
expansivity are tabulated in Table 2 and Fig. 1. The values of isothermal expansivity tends to increase with increase in temperature for all the mole fractions and various concentrations. The isothermal expansivity values of aqueous BPA increased with increase in concentration of BPA, DES1 had higher isothermal expansivity value compared to BPA. It can also be observed that with increase in the composition of aqueous BPA in the mixture the isothermal expansivity value tends to decrease. The isothermal expansivity value range from 4.09 × 10−4 to 6.23 × 10−4 K−1. The values of isothermal expansivity indirectly reflect the interaction between the molecules of the mixtures. The observed positive values of excess isothermal expansivities for this mixture system signifies the temperature dependence of interactions between unlike interactions is more necessary than like-like interactions in presence of great quantities of DES (Anouti et al., 2009). The α E value is maximum in the mole fractions 0.4 and 0.6 of aqueous BPA with the range of 1.15 × 10−4 to 1.27 × 10−4 with increase in temperature. The pure component and binary mixture molar volume can be calculated by using the following equation (Centers for Disease Control and Prevention (CDC), 2009). Molar volume of component 1 and 2,
V10 =
x2 M2 ρ2
VmE = Vmixture − x1 V10 − x2 V20
(8)
x M + x2 M2 ⎤ ⎡ x1 M1 xM VmE = ⎡ 1 1 − + 2 2⎤ ⎢ ρ ⎥ ⎢ ρ ρ2 ⎥ mixture ⎦ ⎣ ⎦ ⎣ 1
(9)
Fig. 2 shows that excess molar volume has positive values for all concentrations which indicated that the dispersive interaction between mixture components. This interaction arises due to the breaking of cohesive forces acting with in like molecules as increase the excess molar volume. The highest positive excess molar volume at the mole fraction 0.5 of aqueous BPA denotes the breaking up of hydrogen bond in the binary mixtures is maximum in the composition (Bisphenol, 2014). This trend is observed in various temperatures with respect to mole fraction and the values of VE increases slightly with increase in temperature. Also the positive contribution of excess molar volume denotes the occurrence of physical interaction which consists of dispersion forces or weak dipole-dipole interaction. The temperature effect on the excess molar volume is due to the increase in kinetic energy which does not change the interaction of hydrogen bonds. It can be seen that sign and magnitude of excess molar volume gives a good estimate of unlike interactions in the binary mixtures (Bisphenol, 2014). Here, the mixtures of aqueous BPA+ DES1 leads to volume increase owing to increase in repulsive interactions or the replacement of short range by long range intermolecular interactions (Wankhede et al., 2006). The partial molar volume can be calculated by the following equation (Bisphenol, 2014). Partial molar volume of component 1;
(5)
Fig. 1. The Excess isothermal Expansivity. 55
South African Journal of Chemical Engineering 27 (2019) 53–59
K. Ashwini et al.
Fig. 2. Excess molar volume vs. mole fraction. E
∂V − V1 = VmE + V10 + x2 ⎛⎜ m ⎞⎟ ⎝ ∂x1 ⎠P, T
following equation: Excess Partial molar volume of component 1;
(10)
− − V1E = V1 − V10
Partial molar volume of component 2; E
∂V − V2 = VmE + V20 − x1 ⎛⎜ m ⎞⎟ ⎝ ∂x1 ⎠P, T
(12)
Excess Partial molar volume of component 2; (11)
− − V2E = V2 − V20
The values of V1 with respect to component 2 of the mixture, the peak value is found in the mole fraction 0.8 of component 1 and V2 has a peak value at 0.3 value of x1 and again with increase of composition in the mixture the values decreases. This shows that beyond the peak values there is accommodation of constituent molecules of the mixture within each other. From Fig. 3, the partial molar volume increases with increase in temperature for various concentrations. The value of partial molar volume is in the range of 230–240 cm3mol-1 which indicates that the solute-solvent interactions is very high in this system and the temperature does not play a significant role in this system which states that there is no much correlation between the temperature and solution interactions (Omrani et al., 2010). Excess partial molar volume is characterized for the non-ideal behavior of the mixtures. The excess partial molar volume can be obtained for the aqueous. BPA+DES1 mixture system interaction using the
(13)
It can be seen that excess partial molar volume has positive values for all temperatures and various mole fractions which shows that weaker solute-solvent interactions of mixture have taken place (Anouti et al., 2009). At the equimolar ratio the values of V1E and V2E are maximum which shows that the positive interactions are maximum at this point (Figs. 4 and 5 and Supporting Tables 1.1–1.5). The apparent molar property of a binary mixture contributes the non-ideality of each component in the mixture. Its shows the changes in the corresponding solution properties, when a component is added to the solution. It is described as apparent because it appears to be the molar property of a component in a binary mixture. The apparent molar volume of the binary system can be calculated as using the following equation, Apparent Molar volume of component 1,
Fig. 3. Partial molar volume at 298.15 K. 56
South African Journal of Chemical Engineering 27 (2019) 53–59
K. Ashwini et al.
Fig. 4. Excess partial molar volume of aq.BPA at 298.15 K.
VE Vφ,1 = ⎡V10 − m ⎤ ⎢ x1 ⎥ ⎣ ⎦
BPA and DES1 for temperatures from 293.15 K to 343.15 K with 5 K interval describes that aqueous BPA and DES have high molecular interactions in the range of 0.4, 0.5 and 0.6 mole fraction at ambient conditions so this range of aqueous BPA was chosen for the extraction studies of BPA from aqueous medium. The extraction process used had change in hydrogen bond donor in deep eutectic solvent with decanoic acid due to its hydrophobic nature. The aqueous BPA and DES2 (tetrabutyl ammonium bromide + decanoic acid) mixture formed heterogeneous system was favorable for the extraction process.
(14)
Apparent Molar volume of component 2,
VE Vφ,2 = ⎡V20 − m ⎤ ⎢ x2 ⎥ ⎣ ⎦
(15)
From Fig. 6, the apparent molar volume can be interpreted in terms of solute-solute interactions. The parameter apparent molar volume is the volumetric coefficient that characterizes the pairwise interaction of solvated solute species in binary mixtures. The sign of apparent molar volume indicates the nature of the interaction between the solute species. On the other hand, the overlap of two hydrophobic hydration cospheres when a polar group interacts leads to a negative volume change, and hence a negative sign of apparent molar volume. The V∅ ,1 values follow a linear trend and ascends from negative to positive values with the increase in composition of aqueous BPA in the mixture and V∅ ,2 also follows the same trends as aqueous BPA, with increase in the composition of DES1 the values moves from negative to positive interactions. The study on thermodynamic properties such as excess molar volume, partial molar volume, excess partial molar volume, apparent molar volume and isothermal expansivity for the mixture of aqueous
3.2. Extraction of BPA Extraction is carried out at room temperature, due to limited solubility of BPA in water, a known amount of BPA was dissolved in deionized water to prepare aqueous BPA concentrations 5, 10, 15, 20 and 25 ppm (Omrani et al., 2010; Fan et al., 2008). The aqueous and the DES layer were separated and analyzed for the BPA concentrations at 275 nm. The concentration values of BPA in both the layer were collected and was used to calculate the parameters of extraction such as distribution ratio and percentage of extraction. The distribution ratio of the BPA between DES2 (tetrabutyl ammonium bromide + decanoic acid) and aqueous layer can be calculated by the following equation
Fig. 5. Excess partial molar volume of DES (TBAB- Glycerol) at 298.15 K 57
South African Journal of Chemical Engineering 27 (2019) 53–59
K. Ashwini et al.
Fig. 6. Apparent molar volumes for binary mixture at 298.15 K.
D=
CDES CAq
liquid (LLE) extraction process, the highest extraction efficiency of 98% was achieved using DES2 as extraction solvent media.
(16)
From Table 3, the distribution ratio increased with the increase in concentration of aqueous BPA, and also with increase in the composition of aqueous BPA in the mixture. Distribution ratio also increases with the hydrogen bond interaction of BPA with DES2. The distribution ratio study suggests that hydrogen bonding and hydrophobic behavior of the DES and BPA leads to the extraction of higher quantity of BPA from aqueous rich phase to DES2 rich phase. The extraction efficiency is known for the efficient separation of BPA from aqueous solution using DES solvent. The extraction is carried out to separate the BPA from the aqueous solution and the difference in the concentration is calculated. The ratio between concentrations of BPA in DES2 (CDES) to total concentration of the BPA in the mixture system (CDES + CAqueous) is predicted. The following equation used to find out the percentage extraction of BPA in aqueous solution.
E=
CDES × 100 (CDES + CAq )
4. Conclusion The density of the mixture of aqueous BPA with DES1 decreased with the decrease in mole fraction of the DES1. This experimental data could be used in future to evaluate the kinetic parameters and industrial application. The LLE method was studied for the extraction of BPA from their solution using DES2. The mixture of aqueous BPA + DES2 (tetrabutylammonium bromide + decanoic acid) formed a heterogeneous mixture which favored the extraction, as BPA has hydrophobic nature which lead to the extraction of BPA from aqueous phase to hydrophobic DES2 rich phase. From the experimental data, the distribution ratio and extraction efficiency were calculated. It was found that the distribution ratio of BPA increased with increase in composition of DES2 in the mixture and the extraction efficiency was achieved very high with in the range of 80–99%. The hydrogen bonding and hydrophobic interaction between DES2 and the BPA played an important role in the extraction technique. It could be conclude that the deep eutectic solvents can be used as potential solvent for the removal of BPA from water matrices.
(17)
The results are given in Table 3 and the extraction efficiency can be interpreted by an increase of hydrogen bonding interaction between BPA compound in aqueous solution and the DES to achieve the efficiency, where they have greater distribution ratio to achieve the higher extraction efficiency, this study suggests that the decrease in hydrogen bonding interaction between the BPA and DES probably the extraction efficiency of BPA were decreased (Omrani et al., 2010). There are two phenolic hydroxyls and two aromatic rings present in the BPA molecules, so stronger interaction has occurred with hydrophobic DES2. The extraction also depends on the pH of the aqueous phase of the extraction process. The maximum removal of BPA from aqueous phase can be obtained in acidic pH (Omrani et al., 2010; Fan et al., 2008; Zhong et al., 2007). The pH of the aqueous BPA ranged from 2.0 to 2.5. The percentage of extraction have also increased with the increase in the composition of aqueous BPA. The extraction percentage ranged from 80 to 99% for various concentrations of aqueous BPA. From the liquid-
Conflicts of interest I am sure that there is no conflict in any manner in this manuscript including data and text, etc.
Acknowledgement The financial support from Science and Engineering Research Board – DST (YSS/2015/001546), India & SSN Trust, Chennai, Tamil Nadu, is gratefully acknowledged.
Table 3 Distribution ratio and Extraction efficiency at varies concentration. Concentration of BPA solution (ppm)
5
X (mole fraction of aqueous solution) pH Distribution ratio Extraction efficiency %
0.4 2.08 8.05 88.95
10 0.5 2.32 8.75 89.74
0.6 2.34 9.41 90.39
0.4 2.11 11.93 92.27
15 0.5 2.27 6.31 86.32
0.6 2.28 19.99 95.24
58
0.4 2.1 3.97 79.9
20 0.5 2.22 42.54 97.7
0.6 2.32 33.67 97.12
0.4 2.16 11.79 92.18
25 0.5 2.18 5.48 84.58
0.6 2.33 18.58 94.89
0.4 2.06 5.59 84.82
0.5 2.18 16.9 94.41
0.6 2.32 82.39 98.8
South African Journal of Chemical Engineering 27 (2019) 53–59
K. Ashwini et al.
Appendix A. Supplementary data
Chemicals, Executive Summary. Atlanta, GA. http://www.cdc.gov/exposurereport/. Fan, Jing, Fan, Yunchang, Pei, Yuanchao, KunWua, Wang, Jianji, Fan, Maohong, 2008. Solvent extraction of selected endocrine-disrupting phenols using ionic liquids. Separ. Purif. Technol. 61, 324–331. Green Chem. 15, 2793–2795. Muz, M., Sonmez, S., Komesli, O.T., Bakrdere, S., Gokcay, C.F., 2012. Analyst 137, 884–889. Omrani, Abdollah, Rostami, Abbas Ali, Mokhtary, Maryam, 2010. Densities and volumetric properties of 1,4-dioxane with ethanol, 3-methyl-1-butanol, 3-amino-1-propanol and 2-propanol binary mixtures at various temperatures. J. Mol. Liq. 157, 18–24. Wang, G., Ma, P., Zhang, Q., Lewis, J., Lacy, M., Furukawa, Y., Reilly, S.E.O., Meaux, S., McLachlan, J., Zhang, S., 2012. J. Envion. Monit 14 1353-1353. Wankhede, N.N., Wankhede, D.S., Lande, M.K., Arbad, B.R., 2006. Molecular interactions in (2, 4,6-trimethyl-1,3,5-trioxane + n-alkyl acetates) at T = (298.15, 303.15, and 308.15) K. J. Chem. Thermodyn. 38, 1664–1668. Zhong, Yanwei, Wang, Haiju, Diao, Kaishen, 2007. Densities and excess volumes of binary mixtures of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate with aromatic compound at T=(293.15 to 313.15) K. J. Chem. Thermodyn. 39, 291–296.
Supplementary data to this article can be found online at https:// doi.org/10.1016/j.sajce.2018.12.003. References Anouti, Meriem, Caillon-Caravanier, Magaly, Dridi, Yosra, Jacquemin, Johan, Hardacre, Christopher, Lemordant, Daniel, 2009. Liquid densities, heat capacities, refractive index and excess quantities for {protic ionic liquids+ water} binary system. J. Chem. Thermodyn. 41, 799–808. Basile, T., Petrella, A., Petrella, M., Boghetich, G., Petruzzelli, V., Colasuonno, S., Petruzzelli, D., 2011. Ind. Eng. Chem. Res. 50, 8389–8401. BenFredj, S., Nobbs, J., Tizaoui, C., Monser, L., 2015. Chem. Eng. J. 262, 417–426. Bisphenol, A.(B.P.A.), 2014. World Market Outlook and Forecast up to 2018. Cabo, B.R., Francisco, M., Soto, A., Arce, A., 2012. Fluid Phase Equil. 314, 107–112. Centers for Disease Control and Prevention (CDC), 2009. National Center for Environmental Health, Fourth National Report on Human Exposure to Environmental
59