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Bioremoval of Malachite green from water sample by forestry waste mixture as potential biosorbent
Accepted Manuscript Bioremoval of Malachite green from water sample by forestry waste mixture as potential biosorbent
Fatih Deniz, Remziye Aysun Kepekci PII: DOI: Reference:
S0026-265X(16)30549-5 doi: 10.1016/j.microc.2017.01.015 MICROC 2668
To appear in:
Microchemical Journal
Received date: Revised date: Accepted date:
2 November 2016 17 January 2017 21 January 2017
Please cite this article as: Fatih Deniz, Remziye Aysun Kepekci , Bioremoval of Malachite green from water sample by forestry waste mixture as potential biosorbent. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Microc(2017), doi: 10.1016/j.microc.2017.01.015
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ACCEPTED MANUSCRIPT Bioremoval of Malachite green from water sample by forestry waste mixture as potential biosorbent Fatih Deniz a,*, Remziye Aysun Kepekci b a
Department of Environmental Engineering, Faculty of Engineering and Architecture, Sinop University, 57000 Sinop, Turkey
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Department of Food Processing, Vocational High School of Technical Sciences, Gaziantep
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University, 27310 Gaziantep, Turkey
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* Corresponding author. Tel.: +90 368 2715516; fax: +90 368 2714152
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E-mail address: [email protected] (F. Deniz)
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b
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ACCEPTED MANUSCRIPT Abstract Application of cetyltrimethylammonium bromide (CTAB) modified multi-component biosorbent composed of pine, oak, hornbeam and fir sawdust biomasses was investigated to remove Malachite green (MG) as a model pollutant from aqueous solution. The effects of pH, dye concentration, biosorbent amount and contact time on the biosorption performance were
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explored in a batch biosorption system. The biosorption isotherm data were analyzed using
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Freundlich, Langmuir, Sips and Dubinin-Radushkevich models while the kinetic data of
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biosorption were modelled with the pseudo-first-order, pseudo-second-order, Elovich, logistic and intra-particle diffusion models. These studies showed that Sips isotherm and logistic
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model fitted well to the dye biosorption data. The maximum biosorption capacity of biosorbent was calculated to be 52.610 mg g-1 at the optimized conditions. Thus, the CTAB
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modified multi-component sawdust biomass can be employed as cost effective and ecological friendly biosorbent in the treatment of industrial effluents containing such unsafe pollutants.
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Keywords: Phytosorbents; Sawdust; Biosorption; Synthetic dyes
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ACCEPTED MANUSCRIPT 1. Introduction Synthetic dyes are widely used in many areas such as paper, textile, food, cosmetic, leather, plastic and pharmaceutical industries. An important amount of these pollutants are commonly present in the effluents of above industries [1]. Unless properly treated, synthetic dyes may affect aesthetic condition of water bodies and compromise many water uses. Also,
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they may pose serious risks to aquatic life and human health [2, 3]. Therefore, the effluents
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containing synthetic dyes need to be treated to minimize their threat to the environment. One
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of the most used synthetic dyes is Malachite green (MG). MG, a triarylmethane dye, is widely used for different purposes in various industrial fields such as textile, food, paper and other
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biological fields. However, MG presented many adverse characteristics because of its high toxicity, as well as teratogenic, carcinogenic, and mutagenic properties. Although different
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authorities all over the world have applied restrictions for the usage of MG, it is still used in many countries due to its low cost and availability [4-6].
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Many different types of treatment processes including ion exchange, coagulation,
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flocculation, membrane filtration and chemical oxidation have been used to remove such synthetic unsafe dyes from polluted effluents. These methods have some disadvantages such
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as incomplete removal, high reagent and energy requirements, and generation of toxic sludge or other waste products that require disposal [7, 8]. Hence, the removal of hazardous dyes to
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an environmentally safe level in a cost effective and environmentally friendly manner assumes great importance. Among the emerging remediation technologies for dye impurity, biosorption of synthetic dyes using natural biomasses or agro-industrial wastes and byproducts is known to be a feasible and efficient alternative considering numerous biosorbent sources, low operational costs, high removal efficiency and low secondary pollution risk [911]. As a natural waste biomass, sawdust generated in abundance from forestry and agricultural activities in particular has various important advantages in terms of cost, quantity,
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ACCEPTED MANUSCRIPT renewability and biodegradability. It mainly consists of cellulose, hemicellulose and lignin. These properties make sawdust a suitable biomass for pollutant biosorption. Many biosorption studies involving different unwanted materials and sawdust residues have been performed earlier [12-15]. However, to the best of our knowledge, performance of different types of sawdust biomass in biosorption system has been evaluated individually. Besides, current
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studies have focused on applying different modification agents to improve biosorption
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capacities of biosorbents, and this operation showed a great improvement [16, 17]. Hence,
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cetyltrimethylammonium bromide (CTAB) as a model modification agent was first applied to modify a novel multi-component biosorbent composed of pine, oak, hornbeam and fir
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sawdust biomasses, aiming to obtain an effective biosorbent for MG dye in this study. Different process variables were evaluated for optimal biosorption conditions. Performance
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estimation of batch biosorption system was achieved by appropriate mathematical modeling. 2. Materials and methods
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2.1. Reagents
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Malachite green (MG, Type: triarylmethane, C.I. name: basic green 4, molecular formula: C23H25ClN2, molecular weight: 364.911 g mol-1, maximum absorbance: 617 nm) was supplied
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from Carlo Erba. A stock solution of MG (1 g L-1) was prepared by dissolving required amount of the dye in distilled water. The experimental concentration of MG in the aqueous
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solution was varied from 10 to 30 mg L-1 by diluting the dye stock solution with distilled water. Cetyltrimethylammonium bromide (CTAB) was obtained from Sigma. All chemicals used were of analytical reagent grade. 2.2. Biosorbent and modification operation Natural sawdust mix composed of pine, oak, hornbeam and fir biomasses was obtained from a local source in Sinop, Turkey. This material was washed with tap water, followed by several washings with distilled water to remove extraneous materials. It was dried at 100 °C
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ACCEPTED MANUSCRIPT in an oven until a constant weight was achieved. The dried biomass was then sieved through a 0.5 mm standard sieve and kept in a glass bottle for modification study. Before modification reaction, the cation exchange capacity of biomass was improved using a sodium chloride salt solution. For this purpose, the powdered biosorbent sample (1 g) was mixed with 100 mL of sodium chloride solution (1 mol L-1) by a magnetic shaker at room temperature for 24 h. The
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material was then separated from the mixture by filtration, washed with distilled water several
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times to remove residual salt ions and dried. Then, this pretreated sample was reacted with
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100 mL of CTAB solution (0.1 mol L-1) by a magnetic shaker at room temperature for 24 h. After this reaction, the solid phase was separated by filtration, then washed several times with
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distilled water to remove any excess modification agent and dried as mentioned above. The final modified product obtained was stored in a glass bottle for biosorption studies.
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2.3. Experimental setup
Biosorption assays were performed in a batch mode to optimize different process variables
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such as contact time, pH of medium, biosorbent loading and MG concentration at room
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temperature. The pH of solution was adjusted with sodium hydroxide (0.1 mol L-1) and hydrochloric acid (0.1 mol L-1). A known weight of modified biosorbent was added to a series
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of 100 mL Erlenmeyer flasks containing 100 mL of MG solution and the flasks were periodically shaken at a constant speed. After equilibration, to separate the solid phase from
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reaction medium, the solution was centrifuged and final concentration of MG was measured using UV-visible spectrophotometer (Thermo, Genesys 10 S) at a wavelength of 617 nm. The biosorption potential of biosorbent, qt or qe (mg g-1), was estimated using the following equations:
qt
qe
C0 Ct V M
C0 Ce V M
…………………….. (1)
…………………….. (2) 5
ACCEPTED MANUSCRIPT where C0, Ct and Ce (mg L-1) are the concentrations of MG at the initial, a time t and equilibrium, respectively. V (L) is the volume of aqueous MG solution and M (g) is the mass of modified biosorbent. 2.4. Biosorption isotherms Equilibrium studies were carried out using biosorbent masses of 10 mg in Erlenmeyer
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flasks containing 100 mL of MG solutions of varying concentrations (10-30 mg L-1) for a
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period of time equal to the equilibrium at optimum pH of medium. The flasks were
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periodically shaken at constant temperature and speed. After biosorption equilibrium, the samples were centrifuged and then the concentrations of residual dye in the supernatants were
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calculated as described above. The experimental equilibrium data of MG biosorption were modeled using Freundlich, Langmuir, Sips and Dubinin-Radushkevich isotherm equations.
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Freundlich model [18] is applied to multilayer biosorption, with non-uniform distribution of biosorption heat and affinities over the heterogeneous surface and its equation can be given
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by:
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qe KFCe1/ nF …………………….. (3)
where qe (mg g-1) is the dye biosorption capacity of biosorbent at the equilibrium. Ce (mg L-1)
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is the dye concentration at equilibrium. KF (mg g-1 (L mg-1)1/nF) and nF (-) are Freundlich
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isotherm constants related to biosorption capacity and intensity, respectively. Langmuir isotherm [19] supposes that the biosorption process comes from the monolayer coverage of biosorbate over a homogenous biosorbent surface and that biosorption occurs on specific homogeneous sites within the biosorbent and all its biosorption sites are energetically identical. This model can be written as:
qe
qm K LCe …………………….. (4) 1+K LCe
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ACCEPTED MANUSCRIPT where qm (mg g-1) is the maximum biosorption capacity of biosorbent. KL (L mg-1) is Langmuir equilibrium constant related to the biosorption energy. Sips model [20] inherently includes the features of Freundlich and Langmuir models and has more capability in describing biosorption equilibrium. Sips equation can be shown by:
qm ( KSCe )1/ nS …………………….. (5) 1+( KSCe )1/ nS
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qe
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where KS (L mg-1)1/nS is Sips equilibrium constant and nS (-) is the isotherm model exponent. Dubinin-Radushkevich isotherm [21] is usually applied to estimate the nature of
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biosorption process and can be represented as:
qe qme B …………………….. (6)
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where B (mol2 kJ-2) is a constant related to the mean free energy of biosorption, Ɛ is the
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Polanyi potential which is equal to RT ln (1 + (1/Ce)). R (J mol-1 K-1) is the universal gas constant and T (K) is the absolute temperature. The computations of parameters of these
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models were done by non-linear regression using SigmaPlot 12.0 software. The goodness of
square error (RMSE).
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2.5. Biosorption kinetics
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the fit and best model was argued using the coefficient of determination (R2) and root mean
Kinetic investigations were performed in Erlenmeyer flasks containing 100 mL of MG
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solutions (10-30 mg L-1) with 10 mg of biosorbents. The flasks were periodically shaken at a constant speed. The samples were taken at predetermined time intervals, centrifuged and analyzed for the residual MG concentrations. The pseudo-first-order, pseudo-second-order, Elovich, logistic and intra-particle diffusion equations were used to model the MG biosorption kinetics. The pseudo-first-order model [22] considers the rate of occupation of biosorption sites proportional to the number of unoccupied sites and can be shown by:
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ACCEPTED MANUSCRIPT qt qe (1 e k1t ) …………………….. (7) where qt and qe (mg g-1) are the biosorption capacity of dye at a time t and the equilibrium, respectively. k1 (min-1) is the biosorption rate constant of pseudo-first-order model. The pseudo-second-order kinetics model [23] is usually associated with the situation when the rate of direct biosorption/desorption process controls the overall biosorption kinetics and
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k2 qe 2t …………………….. (8) 1 k2 qet
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qt
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its equation can be given as:
where k2 (g mg-1 min-1) is the pseudo-second-order rate constant.
be written as:
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ln(1+ t ) …………………….. (9)
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qt
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Elovich model [24] is suitable for systems with heterogeneous biosorbing surfaces and can
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where α (mg g-1 min-1) is the initial biosorption rate and β (g mg-1) is the desorption constant.
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The logistic model [25] has been used successfully to define biosorption kinetics in recent times and can be indicated as: q
1 e
e kL ( t tc )
…………………….. (10)
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qt
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where kL (min-1) is the maximum relative biosorption rate constant and tc (min) is the time value in the midpoint of qe. The intra-particle diffusion model [26] is generally used to explain the diffusion mechanism of biosorption process. This model can be expressed by:
qt kp t1/2 C …………………….. (11) where kp (mg g-1 min-1/2) is the intra-particle diffusion rate constant and C (mg g-1) is a constant providing information about the thickness of boundary layer. The computations of
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ACCEPTED MANUSCRIPT constants of kinetic models were done by non-linear regression using SigmaPlot 12.0 software. The goodness of the fit and best model was discussed using R2 and RMSE. 2.6. Biosorption thermodynamics As a significant thermodynamic parameter, the change of standard Gibbs free energy (ΔG°) was calculated to explore the suitability, spontaneity and nature of MG biosorption.
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The value of ΔG° can be estimated by [27]:
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G RT ln KD …………………….. (12)
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where KD (Cs/Ce) is the distribution coefficient. Cs and Ce (mg L-1) are the equilibrium dye concentrations on biosorbent and in solution, respectively.
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2.7. Characterization
Scanning electron microscopy (SEM, Zeiss Evo Ls 10) was used to reveal the surface
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structure of modified biosorbent. The infrared spectra of biosorbent before and after the dye biosorption were obtained using PerkinElmer Fourier transform infrared spectrometer (FTIR,
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3. Results and discussion
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Spectrum 400) to identify the possible effective active sites for MG biosorption.
3.1. Effect of contact time
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Fig. 1(a) presents the effect of contact time on the biosorption of MG onto the modified biosorbent. The biosorption capacity of biosorbent significantly increased within the first 60
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min and slowly reached to equilibrium within 120 min. Further extending the contact time did not improve the biosorption potential of biosorbent for MG. The initial high rate might relate to the large numbers of available sites on the surface of biosorbent and the subsequently decreased biosorption rate was probably due to gradual occupancy of those free binding sites [7, 10]. 3.2. Effect of MG concentration
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ACCEPTED MANUSCRIPT The response of MG biosorption onto the biosorbent as a function of dye concentration is shown in Fig. 1(b). As the initial MG concentration increased from 10 to 30 mg L-1, the biosorption capacity increased from 17.879 to 52.525 mg g-1. This trend might be due to the increase in the necessary driving force to overcome the resistances to the mass transfer of MG between the aqueous and solid stages [28].
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3.3. Effect of pH
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The medium pH is a critical parameter in biosorption system. It strongly affects the surface
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charge of biosorbent, the degree of ionization and the speciation of biosorbates (e.g., dye, metal). The effect of solution pH on the biosorption of MG was studied initially in the pH
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range of 4-8. The removal of dye by the biosorbent increased significantly with an increase in the solution pH as seen in Fig. 1(c). This was purely due to the involvement of ionic
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interactions in the biosorption process. Since the surface charge of biosorbent is positive at lower pH, the competitive effects of the surrounding H+ ions as well as electrostatic repulsion
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between the dye cation and the positively charged active biosorption sites on the surface of
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biosorbent lead to a decrease in the dye removal. In contrast, at higher pH, the biosorbent surface has a negative charge leading to rising cationic MG biosorption due to electrostatic
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attraction forces [1].
3.4. Effect of biosorbent loading
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The biosorbent amount is a significant parameter as it determines the biosorption capacity for a given pollutant concentration. The biosorbent quantity was studied in the range of 10-30 mg and the response graph is displayed in Fig. 1(d). The biosorption capacity observed higher at lower biosorbent amount. This behavior could be explained by the partial aggregation of biomass resulting in a lower effective surface area [7, 29]. 3.5. Isotherm studies
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ACCEPTED MANUSCRIPT The equilibrium relationships between biosorbent and biosorbate are described by biosorption isotherms, as they are the ratio between the quantities biosorbed on the biosorbent and remained in the solution at a fixed temperature at equilibrium. Isotherm modeling is important for the design of biosorption systems, the prediction and comparison of biosorption capacity of biosorbents and characterization of surface properties and affinity of biosorbent
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[7, 10]. Hence, Freundlich, Langmuir, Sips and Dubinin-Radushkevich isotherm models were
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employed to describe the biosorption equilibrium characteristics of MG bioremediation. The
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biosorption isotherms for MG biosorption onto the biosorbent are given in Fig. 2 and the related parameters are listed in Table 1. In view of the results presented in the figure and
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table, Sips model had the best fitting to the experimental data for MG biosorption, evidenced by the values of R2 and RMSE. Sips isotherm model incorporates the features of Langmuir
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and Freundlich equations. The heterogeneity factor of nS close to or even 1 shows biosorbent with comparatively homogenous binding sites, while nS close to 0 displays heterogeneous
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biosorbent. This constant was calculated to be 0.140, which implied that the model looked
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more like Freundlich model than Langmuir model for the biosorption of MG onto the relatively heterogeneous surface of biosorbent [9]. In addition, the biosorption capacity of
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modified biosorbent was comparable with those of other biosorbents reported in literature for MG removal [30-32]. This highlighted its potential usage for unsafe MG dye removal as an
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effective, low cost and ecological friendly biosorbent. The equilibrium parameter or separation factor (RL) obtained from Langmuir model executed favorable dye biosorption [10]. From Freundlich isotherm, the value of nF constant, falling in the range of 1-10 also showed a suitable biosorption process [7]. The free energy of biosorption, E (kJ mol-1), obtained from Dubinin-Radushkevich model is usually applied to distinguish the nature of biosorption. When the value of E, is in the range 816 kJ mol-1, the biosorption process is a chemical ion exchange process, while for E value < 8
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ACCEPTED MANUSCRIPT kJ mol-1, the biosorption mechanism occurs through a physical process [33]. According to the E value obtained for the present study, the biosorption of MG seems to involve physical mechanism. 3.6. Kinetic and mechanism studies The determination of operational and kinetic parameters is important in the biotreatment of
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wastewater as it provides us valuable insights into the biosorption reaction mechanism. In this
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study, the pseudo-first-order, pseudo-second-order, Elovich, logistic and intra-particle diffusion models were applied to interpret the biosorption kinetic data. The kinetic constants
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and statistical analysis data are demonstrated in Table 2. Fig. 3(a-c). The values of R2 and
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RMSE from the table revealed that the biosorption process was better described by the logistic equation than the other models. In addition, the estimated biosorption capacity of
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biosorbent for MG by the logistic model was very close to the experimental one. These findings showed that the logistic model was preferable for the biosorption of MG onto the
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modified biosorbent. On the other hand, the intra-particle diffusion model was used to identify
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the possible mechanism(s) involved in the biosorption process. The intra-particle diffusion plots are illustrated in Fig. 3(d) for MG biosorption. As shown in the figure, the straight lines
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did not go through the origin, indicating that the pore diffusion was not the only ratecontrolling step [9, 33]. This suggested that the surface biosorption and intra-particle diffusion
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might contribute to the biosorption of MG onto the modified biosorbent. 3.7. Thermodynamic studies In engineering practice, values of thermodynamic parameters like the standard free energy change of Gibbs (ΔG°) should be taken into consideration in order to determine the spontaneity, feasibility and nature of biosorption process. The biosorption free energy change was calculated using Eq. (12) and the obtained values were -1.494, -1.701 and -2.877 kJ mol-1 for MG concentrations of 10, 20 and 30 mg L-1. The change of Gibbs free energy for physical
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ACCEPTED MANUSCRIPT biosorption is in the range of 0 to -20 kJ mol-1, while for chemical biosorption, it is in the range of -80 to -400 kJ mol-1 [34]. The negative ΔG° value showed that this biosorption process was spontaneous, feasible and physical in the studied temperature. 3.8. Characterization studies The SEM images obtained before and after MG biosorption onto the modified biosorbent
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are showed in Fig. 4. The biosorbent possessed heterogeneous surface morphology. After the
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biosorption of dye, this structure was covered with MG molecules. On the other hand, the FTIR spectra before and after the biosorption of dye are given in Fig. 5. The strong and broad
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band at around 3333 cm-1 is attributed to O-H stretching vibration [35]. The peak at around
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2891 cm-1 is assigned to the stretching vibration of C-H [36]. The bands observed between 1750 and 1500 cm-1 correspond to C=O and C=C stretching vibrations [15]. The peaks
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between 1460 and 1300 cm-1 refer to the bending vibrations of O-H and C-H groups [15, 37]. The bands appeared between 1300 and 1100 cm-1 are attributed to C-O stretching vibration
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[38]. A strong peak at around 1027 cm-1 is ascribed to C-O-C stretching [39]. The bands seen
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between 900 and 800 cm-1 are due to the bending vibration of C-H [12, 15]. The band shifts after the dye loading revealed that various chemical groups particularly observed at around
4. Conclusions
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3333, 2891, 1736, 1598, 1372, 1314, 1263 and 893 cm-1 might contribute to MG biosorption.
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The CTAB modified multi-component biosorbent is a potential biosorption agent for the removal of MG from aqueous solution. The biosorption process was affected by the medium pH, biosorbent quantity, reaction time and MG concentration. The biosorption data fitted well with Sips and the logistic models, and the maximum biosorption capacity was 52.610 mg g-1. The pore diffusion and surface biosorption were the main mechanisms involved in dye removal. This natural biosorbent can be a good candidate to remediate water bodies polluted with such hazardous dyes.
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ACCEPTED MANUSCRIPT References [1] K.Y. Hor, J.M.C. Chee, M.N. Chong, B. Jin, C. Saint, P.E. Poh, R. Aryal, Evaluation of physicochemical methods in enhancing the adsorption performance of natural zeolite as lowcost adsorbent of methylene blue dye from wastewater, J. Clean. Prod., 118 (2016) 197-209. [2] S.C.R. Santos, R.A.R. Boaventura, Adsorption of cationic and anionic azo dyes on
PT
sepiolite clay: Equilibrium and kinetic studies in batch mode, J. Environ. Chem. Eng., 4
RI
(2016) 1473-1483.
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[3] F. Deniz, Color removal from aqueous solutions of metal-containing dye using pine cone, Desalin. Water Treat., 51 (2013) 4573-4581.
NU
[4] S. Torbati, Artificial neural network modeling of biotreatment of malachite green by Spirodela polyrhiza: Study of plant physiological responses and the dye biodegradation
MA
pathway, Process Saf. Environ. Prot., 99 (2016) 11-19.
[5] A.A. El-Zahhar, N.S. Awwad, Removal of malachite green dye from aqueous solutions
D
using organically modified hydroxyapatite, J. Environ. Chem. Eng., 4 (2016) 633-638.
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[6] Z.-z. Lin, H.-y. Zhang, A.-h. Peng, Y.-d. Lin, L. Li, Z.-y. Huang, Determination of malachite green in aquatic products based on magnetic molecularly imprinted polymers, Food
CE
Chem., 200 (2016) 32-37.
[7] Z. Hajahmadi, H. Younesi, N. Bahramifar, H. Khakpour, K. Pirzadeh, Multicomponent
AC
isotherm for biosorption of Zn(II), Co(II) and Cd(II) from ternary mixture onto pretreated dried Aspergillus niger biomass, Water Resour. Ind., 11 (2015) 71-80. [8] F. Deniz, Adsorption properties of low-cost biomaterial derived from Prunus amygdalus L. for dye removal from water, Sci. World J., Article ID 961671 (2013). [9] S. Amirnia, M.B. Ray, A. Margaritis, Copper ion removal by Acer saccharum leaves in a regenerable continuous-flow column, Chem. Eng. J., 287 (2016) 755-764.
14
ACCEPTED MANUSCRIPT [10] J. Huang, D. Liu, J. Lu, H. Wang, X. Wei, J. Liu, Biosorption of reactive black 5 by modified Aspergillus versicolor biomass: Kinetics, capacity and mechanism studies, Colloids Surf., A, 492 (2016) 242-248. [11] F. Deniz, Optimization of biosorption conditions for color removal by Taguchi DOE Methodology, Environ. Prog. Sustain. Energy, 32 (2013) 1129-1133.
PT
[12] S. Benyoucef, M. Amrani, Adsorption of phosphate ions onto low cost Aleppo pine
RI
adsorbent, Desalination, 275 (2011) 231-236.
SC
[13] L. Semerjian, Equilibrium and kinetics of cadmium adsorption from aqueous solutions using untreated Pinus halepensis sawdust, J. Hazard. Mater., 173 (2010) 236-242.
NU
[14] X.-T. Zhao, T. Zeng, Z.J. Hu, H.-W. Gao, C.Y. Zou, Modeling and mechanism of the adsorption of proton onto natural bamboo sawdust, Carbohydr. Polym., 87 (2012) 1199-1205.
MA
[15] D. Sidiras, F. Batzias, E. Schroeder, R. Ranjan, M. Tsapatsis, Dye adsorption on autohydrolyzed pine sawdust in batch and fixed-bed systems, Chem. Eng. J., 171 (2011) 883-
D
896.
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[16] T. Zhou, W. Lu, L. Liu, H. Zhu, Y. Jiao, S. Zhang, R. Han, Effective adsorption of light green anionic dye from solution by CPB modified peanut in column mode, J. Mol. Liq., 211
CE
(2015) 909-914.
[17] A. Hassani, A. Khataee, S. Karaca, M. Karaca, M. Kıranşan, Adsorption of two cationic
AC
textile dyes from water with modified nanoclay: A comparative study by using central composite design, J. Environ. Chem. Eng., 3 (2015) 2738-2749. [18] H.M.F. Freundlich, Over the adsorption in solution, Z. Phys. Chem., 57 (1906) 385-470. [19] I. Langmuir, The adsorption of gases on plane surfaces of glass, mica and platinum, J. Am. Chem. Soc., 40 (1918) 1361-1403. [20] R. Sips, On the structure of a catalyst surface, J. Chem. Phys., 16 (1948) 490-495.
15
ACCEPTED MANUSCRIPT [21] M.M. Dubinin, L.V. Radushkevich, Equation of the characteristic curve of activated charcoal, Proc. Acad. Sci. Phys. Chem. Sec. USSR, 55 (1947) 331-333. [22] S. Lagergren, About the theory of so-called adsorptıon of soluble substances, K. Sven. Vetenskapsakad. Handl., 24 (1898) 1-39. [23] Y.-S. Ho, Review of second-order models for adsorption systems, J. Hazard. Mater., 136
PT
(2006) 681-689.
RI
[24] S. Chien, W. Clayton, Application of Elovich equation to the kinetics of phosphate release and sorption in soils, Soil Sci. Soc. Am. J., 44 (1980) 265-268.
SC
[25] L. Hu, K. Tian, X. Wang, J. Zhang, The “S” curve relationship between export diversity
NU
and economic size of countries, Physica A, 391 (2012) 731-739. [26] W.J. Weber, J.C. Morris, Kinetics of adsorption on carbon from solution, J. Sanit. Eng.
MA
Div. Am. Soc. Civ. Eng., 89 (1963) 31-60.
[27] K.Y. Foo, B.H. Hameed, Insights into the modeling of adsorption isotherm systems,
D
Chem. Eng. J., 156 (2010) 2-10.
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[28] M. Foroughi-dahr, H. Abolghasemi, M. Esmaieli, G. Nazari, B. Rasem, Experimental study on the adsorptive behavior of Congo red in cationic surfactant-modified tea waste,
CE
Process Saf. Environ. Prot., 95 (2015) 226-236. [29] M. Iqbal, N. Iqbal, I.A. Bhatti, N. Ahmad, M. Zahid, Response surface methodology
AC
application in optimization of cadmium adsorption by shoe waste: A good option of waste mitigation by waste, Ecol. Eng., 88 (2016) 265-275. [30] Z. Bekçi, Y. Seki, L. Cavas, Removal of malachite green by using an invasive marine alga Caulerpa racemosa var. cylindracea, J. Hazard. Mater., 161 (2009) 1454-1460. [31] S. Chowdhury, R. Mishra, P. Saha, P. Kushwaha, Adsorption thermodynamics, kinetics and isosteric heat of adsorption of malachite green onto chemically modified rice husk, Desalination, 265 (2011) 159-168.
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ACCEPTED MANUSCRIPT [32] M. Rajabi, B. Mirza, K. Mahanpoor, M. Mirjalili, F. Najafi, O. Moradi, H. Sadegh, R. Shahryari-ghoshekandi, M. Asif, I. Tyagi, S. Agarwal, V.K. Gupta, Adsorption of malachite green from aqueous solution by carboxylate group functionalized multi-walled carbon nanotubes: Determination of equilibrium and kinetics parameters, J. Ind. Eng. Chem., 34 (2016) 130-138.
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[33] P.S. Blanes, M.E. Bordoni, J.C. González, S.I. García, A.M. Atria, L.F. Sala, S.E. Bellú,
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Application of soy hull biomass in removal of Cr(VI) from contaminated waters. Kinetic,
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thermodynamic and continuous sorption studies, J. Environ. Chem. Eng., 4 (2016) 516-526. [34] M. Gholami, M.T. Vardini, G.R. Mahdavinia, Investigation of the effect of magnetic
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particles on the Crystal Violet adsorption onto a novel nanocomposite based on κcarrageenan-g-poly(methacrylic acid), Carbohydr. Polym., 136 (2016) 772-781.
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[35] M.S. Rahman, M.R. Islam, Effects of pH on isotherms modeling for Cu(II) ions adsorption using maple wood sawdust, Chem. Eng. J., 149 (2009) 273-280.
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[36] M.A. Wahab, S. Jellali, N. Jedidi, Ammonium biosorption onto sawdust: FTIR analysis,
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kinetics and adsorption isotherms modeling, Bioresour. Technol., 101 (2010) 5070-5075. [37] O.M. Paska, C. Pacurariu, S.G. Muntean, Kinetic and thermodynamic studies on
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methylene blue biosorption using corn-husk, RSC Adv., 4 (2014) 62621-62630. [38] A. Ahmad, M. Rafatullah, O. Sulaiman, M.H. Ibrahim, R. Hashim, Scavenging
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behaviour of meranti sawdust in the removal of methylene blue from aqueous solution, J. Hazard. Mater., 170 (2009) 357-365. [39] R.K. Gautam, P.K. Gautam, S. Banerjee, V. Rawat, S. Soni, S.K. Sharma, M.C. Chattopadhyaya, Removal of tartrazine by activated carbon biosorbents of Lantana camara: Kinetics, equilibrium modeling and spectroscopic analysis, J. Environ. Chem. Eng., 3 (2015) 79-88.
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ACCEPTED MANUSCRIPT List of Figures Fig. 1. Effects of contact time (a), dye concentration (b), pH (c) and biosorbent quantity (d). Fig. 2. Isotherm models. Fig. 3. Kinetic models for MG concentrations of 10 (a), 20 (b), 30 mg L-1 (c) and intra-particle diffusion plots (d).
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Fig. 4. SEM images of biosorbent before (a) and after (b) MG biosorption.
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Fig. 5. FTIR spectra of biosorbent before (a) and after (b) MG biosorption.
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ACCEPTED MANUSCRIPT Table 1. Biosorption isotherm parameters. Parameter
Value
Freundlich
KF (mg g-1 (L mg-1)1/nF)
4.968
nF (-)
1.369
R2
0.9653
RMSE
3.626
qm (mg g-1)
55.688
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Langmuir
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Model
KL (L mg-1)
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0.024
RL (-)
0.808
R2
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0.9429
RMSE
nS (-)
0.140
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0.094
1.0000
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52.610
KS (L mg-1)1/nS
R2
Dubinin-Radushkevich
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qm (mg g-1)
Sips
4.182
RMSE
-
qm (mg g-1)
63.193
E (kJ mol-1)
0.001
R2
0.8826
RMSE
8.574
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ACCEPTED MANUSCRIPT Table 2. Biosorption kinetic data. Model
MG concentration (mg L-1)
Parameter
10
20
30
qe (mg g-1)
18.203
39.797
46.657
order
k1 (min-1)
0.026
0.032
0.044
R2
0.9652
0.8875
0.7115
RMSE
1.102
4.124
7.506
Pseudo-second-
qe (mg g-1)
23.255
47.699
order
k2 (g mg-1 min-1)
0.001077
R2
0.9765
RMSE
0.906
α (mg g-1 min-1)
3.421
51.014 0.001358
0.9198
0.8059
3.480
6.157
7.000
7.915
0.292
0.143
0.126
0.9128
0.8826
0.8729
1.744
4.211
4.981
qe (mg g-1)
17.629
41.194
53.661
kL (min-1)
0.055
0.047
0.037
tc (min)
29.771
27.501
25.752
R2
0.9736
0.9891
0.9899
RMSE
1.036
1.384
1.520
Intra-particle
C (mg g-1)
0.120
3.091
8.099
diffusion
kp (mg g-1 min-1/2)
1.712
3.570
4.060
R2
0.9908
0.9951
0.9953
RMSE
0.566
0.860
0.956
R2
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RMSE
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β (g mg-1)
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Logistic
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Elovich
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0.001200
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Pseudo-first-
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ACCEPTED MANUSCRIPT (a)
(b)
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(c) (d) Fig. 1. Effects of contact time (a), dye concentration (b), pH (c) and biosorbent quantity (d).
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Fig. 2. Isotherm models.
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ACCEPTED MANUSCRIPT (a)
(b)
T P
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C S U
N A
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(c) (d) -1 Fig. 3. Kinetic models for MG concentrations of 10 (a), 20 (b), 30 mg L (c) and intra-particle diffusion plots (d).
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(b)
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C S U
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M
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C C
A
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Fig. 4. SEM images of biosorbent before (a) and after (b) MG biosorption.
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ACCEPTED MANUSCRIPT (a)
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(b)
C S U
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C C
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Fig. 5. FTIR spectra of biosorbent before (a) and after (b) MG biosorption.
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ACCEPTED MANUSCRIPT Research highlights: A mix biosorbent composed of different sawdust biomasses. Application of CTAB modified biosorbent for biotreatment of Malachite green.
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A good candidate to remediate water bodies polluted with such hazardous dyes.
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Fatih Deniz, Remziye Aysun Kepekci PII: DOI: Reference:
S0026-265X(16)30549-5 doi: 10.1016/j.microc.2017.01.015 MICROC 2668
To appear in:
Microchemical Journal
Received date: Revised date: Accepted date:
2 November 2016 17 January 2017 21 January 2017
Please cite this article as: Fatih Deniz, Remziye Aysun Kepekci , Bioremoval of Malachite green from water sample by forestry waste mixture as potential biosorbent. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Microc(2017), doi: 10.1016/j.microc.2017.01.015
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Bioremoval of Malachite green from water sample by forestry waste mixture as potential biosorbent Fatih Deniz a,*, Remziye Aysun Kepekci b a
Department of Environmental Engineering, Faculty of Engineering and Architecture, Sinop University, 57000 Sinop, Turkey
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Department of Food Processing, Vocational High School of Technical Sciences, Gaziantep
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University, 27310 Gaziantep, Turkey
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* Corresponding author. Tel.: +90 368 2715516; fax: +90 368 2714152
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E-mail address: [email protected] (F. Deniz)
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b
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ACCEPTED MANUSCRIPT Abstract Application of cetyltrimethylammonium bromide (CTAB) modified multi-component biosorbent composed of pine, oak, hornbeam and fir sawdust biomasses was investigated to remove Malachite green (MG) as a model pollutant from aqueous solution. The effects of pH, dye concentration, biosorbent amount and contact time on the biosorption performance were
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explored in a batch biosorption system. The biosorption isotherm data were analyzed using
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Freundlich, Langmuir, Sips and Dubinin-Radushkevich models while the kinetic data of
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biosorption were modelled with the pseudo-first-order, pseudo-second-order, Elovich, logistic and intra-particle diffusion models. These studies showed that Sips isotherm and logistic
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model fitted well to the dye biosorption data. The maximum biosorption capacity of biosorbent was calculated to be 52.610 mg g-1 at the optimized conditions. Thus, the CTAB
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modified multi-component sawdust biomass can be employed as cost effective and ecological friendly biosorbent in the treatment of industrial effluents containing such unsafe pollutants.
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Keywords: Phytosorbents; Sawdust; Biosorption; Synthetic dyes
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ACCEPTED MANUSCRIPT 1. Introduction Synthetic dyes are widely used in many areas such as paper, textile, food, cosmetic, leather, plastic and pharmaceutical industries. An important amount of these pollutants are commonly present in the effluents of above industries [1]. Unless properly treated, synthetic dyes may affect aesthetic condition of water bodies and compromise many water uses. Also,
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they may pose serious risks to aquatic life and human health [2, 3]. Therefore, the effluents
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containing synthetic dyes need to be treated to minimize their threat to the environment. One
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of the most used synthetic dyes is Malachite green (MG). MG, a triarylmethane dye, is widely used for different purposes in various industrial fields such as textile, food, paper and other
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biological fields. However, MG presented many adverse characteristics because of its high toxicity, as well as teratogenic, carcinogenic, and mutagenic properties. Although different
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authorities all over the world have applied restrictions for the usage of MG, it is still used in many countries due to its low cost and availability [4-6].
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Many different types of treatment processes including ion exchange, coagulation,
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flocculation, membrane filtration and chemical oxidation have been used to remove such synthetic unsafe dyes from polluted effluents. These methods have some disadvantages such
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as incomplete removal, high reagent and energy requirements, and generation of toxic sludge or other waste products that require disposal [7, 8]. Hence, the removal of hazardous dyes to
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an environmentally safe level in a cost effective and environmentally friendly manner assumes great importance. Among the emerging remediation technologies for dye impurity, biosorption of synthetic dyes using natural biomasses or agro-industrial wastes and byproducts is known to be a feasible and efficient alternative considering numerous biosorbent sources, low operational costs, high removal efficiency and low secondary pollution risk [911]. As a natural waste biomass, sawdust generated in abundance from forestry and agricultural activities in particular has various important advantages in terms of cost, quantity,
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ACCEPTED MANUSCRIPT renewability and biodegradability. It mainly consists of cellulose, hemicellulose and lignin. These properties make sawdust a suitable biomass for pollutant biosorption. Many biosorption studies involving different unwanted materials and sawdust residues have been performed earlier [12-15]. However, to the best of our knowledge, performance of different types of sawdust biomass in biosorption system has been evaluated individually. Besides, current
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studies have focused on applying different modification agents to improve biosorption
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capacities of biosorbents, and this operation showed a great improvement [16, 17]. Hence,
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cetyltrimethylammonium bromide (CTAB) as a model modification agent was first applied to modify a novel multi-component biosorbent composed of pine, oak, hornbeam and fir
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sawdust biomasses, aiming to obtain an effective biosorbent for MG dye in this study. Different process variables were evaluated for optimal biosorption conditions. Performance
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estimation of batch biosorption system was achieved by appropriate mathematical modeling. 2. Materials and methods
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2.1. Reagents
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Malachite green (MG, Type: triarylmethane, C.I. name: basic green 4, molecular formula: C23H25ClN2, molecular weight: 364.911 g mol-1, maximum absorbance: 617 nm) was supplied
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from Carlo Erba. A stock solution of MG (1 g L-1) was prepared by dissolving required amount of the dye in distilled water. The experimental concentration of MG in the aqueous
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solution was varied from 10 to 30 mg L-1 by diluting the dye stock solution with distilled water. Cetyltrimethylammonium bromide (CTAB) was obtained from Sigma. All chemicals used were of analytical reagent grade. 2.2. Biosorbent and modification operation Natural sawdust mix composed of pine, oak, hornbeam and fir biomasses was obtained from a local source in Sinop, Turkey. This material was washed with tap water, followed by several washings with distilled water to remove extraneous materials. It was dried at 100 °C
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ACCEPTED MANUSCRIPT in an oven until a constant weight was achieved. The dried biomass was then sieved through a 0.5 mm standard sieve and kept in a glass bottle for modification study. Before modification reaction, the cation exchange capacity of biomass was improved using a sodium chloride salt solution. For this purpose, the powdered biosorbent sample (1 g) was mixed with 100 mL of sodium chloride solution (1 mol L-1) by a magnetic shaker at room temperature for 24 h. The
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material was then separated from the mixture by filtration, washed with distilled water several
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times to remove residual salt ions and dried. Then, this pretreated sample was reacted with
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100 mL of CTAB solution (0.1 mol L-1) by a magnetic shaker at room temperature for 24 h. After this reaction, the solid phase was separated by filtration, then washed several times with
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distilled water to remove any excess modification agent and dried as mentioned above. The final modified product obtained was stored in a glass bottle for biosorption studies.
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2.3. Experimental setup
Biosorption assays were performed in a batch mode to optimize different process variables
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such as contact time, pH of medium, biosorbent loading and MG concentration at room
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temperature. The pH of solution was adjusted with sodium hydroxide (0.1 mol L-1) and hydrochloric acid (0.1 mol L-1). A known weight of modified biosorbent was added to a series
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of 100 mL Erlenmeyer flasks containing 100 mL of MG solution and the flasks were periodically shaken at a constant speed. After equilibration, to separate the solid phase from
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reaction medium, the solution was centrifuged and final concentration of MG was measured using UV-visible spectrophotometer (Thermo, Genesys 10 S) at a wavelength of 617 nm. The biosorption potential of biosorbent, qt or qe (mg g-1), was estimated using the following equations:
qt
qe
C0 Ct V M
C0 Ce V M
…………………….. (1)
…………………….. (2) 5
ACCEPTED MANUSCRIPT where C0, Ct and Ce (mg L-1) are the concentrations of MG at the initial, a time t and equilibrium, respectively. V (L) is the volume of aqueous MG solution and M (g) is the mass of modified biosorbent. 2.4. Biosorption isotherms Equilibrium studies were carried out using biosorbent masses of 10 mg in Erlenmeyer
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flasks containing 100 mL of MG solutions of varying concentrations (10-30 mg L-1) for a
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period of time equal to the equilibrium at optimum pH of medium. The flasks were
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periodically shaken at constant temperature and speed. After biosorption equilibrium, the samples were centrifuged and then the concentrations of residual dye in the supernatants were
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calculated as described above. The experimental equilibrium data of MG biosorption were modeled using Freundlich, Langmuir, Sips and Dubinin-Radushkevich isotherm equations.
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Freundlich model [18] is applied to multilayer biosorption, with non-uniform distribution of biosorption heat and affinities over the heterogeneous surface and its equation can be given
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by:
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qe KFCe1/ nF …………………….. (3)
where qe (mg g-1) is the dye biosorption capacity of biosorbent at the equilibrium. Ce (mg L-1)
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is the dye concentration at equilibrium. KF (mg g-1 (L mg-1)1/nF) and nF (-) are Freundlich
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isotherm constants related to biosorption capacity and intensity, respectively. Langmuir isotherm [19] supposes that the biosorption process comes from the monolayer coverage of biosorbate over a homogenous biosorbent surface and that biosorption occurs on specific homogeneous sites within the biosorbent and all its biosorption sites are energetically identical. This model can be written as:
qe
qm K LCe …………………….. (4) 1+K LCe
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ACCEPTED MANUSCRIPT where qm (mg g-1) is the maximum biosorption capacity of biosorbent. KL (L mg-1) is Langmuir equilibrium constant related to the biosorption energy. Sips model [20] inherently includes the features of Freundlich and Langmuir models and has more capability in describing biosorption equilibrium. Sips equation can be shown by:
qm ( KSCe )1/ nS …………………….. (5) 1+( KSCe )1/ nS
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qe
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where KS (L mg-1)1/nS is Sips equilibrium constant and nS (-) is the isotherm model exponent. Dubinin-Radushkevich isotherm [21] is usually applied to estimate the nature of
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biosorption process and can be represented as:
qe qme B …………………….. (6)
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where B (mol2 kJ-2) is a constant related to the mean free energy of biosorption, Ɛ is the
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Polanyi potential which is equal to RT ln (1 + (1/Ce)). R (J mol-1 K-1) is the universal gas constant and T (K) is the absolute temperature. The computations of parameters of these
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square error (RMSE).
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2.5. Biosorption kinetics
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the fit and best model was argued using the coefficient of determination (R2) and root mean
Kinetic investigations were performed in Erlenmeyer flasks containing 100 mL of MG
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solutions (10-30 mg L-1) with 10 mg of biosorbents. The flasks were periodically shaken at a constant speed. The samples were taken at predetermined time intervals, centrifuged and analyzed for the residual MG concentrations. The pseudo-first-order, pseudo-second-order, Elovich, logistic and intra-particle diffusion equations were used to model the MG biosorption kinetics. The pseudo-first-order model [22] considers the rate of occupation of biosorption sites proportional to the number of unoccupied sites and can be shown by:
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ACCEPTED MANUSCRIPT qt qe (1 e k1t ) …………………….. (7) where qt and qe (mg g-1) are the biosorption capacity of dye at a time t and the equilibrium, respectively. k1 (min-1) is the biosorption rate constant of pseudo-first-order model. The pseudo-second-order kinetics model [23] is usually associated with the situation when the rate of direct biosorption/desorption process controls the overall biosorption kinetics and
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k2 qe 2t …………………….. (8) 1 k2 qet
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qt
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its equation can be given as:
where k2 (g mg-1 min-1) is the pseudo-second-order rate constant.
be written as:
1
ln(1+ t ) …………………….. (9)
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qt
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Elovich model [24] is suitable for systems with heterogeneous biosorbing surfaces and can
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where α (mg g-1 min-1) is the initial biosorption rate and β (g mg-1) is the desorption constant.
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The logistic model [25] has been used successfully to define biosorption kinetics in recent times and can be indicated as: q
1 e
e kL ( t tc )
…………………….. (10)
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qt
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where kL (min-1) is the maximum relative biosorption rate constant and tc (min) is the time value in the midpoint of qe. The intra-particle diffusion model [26] is generally used to explain the diffusion mechanism of biosorption process. This model can be expressed by:
qt kp t1/2 C …………………….. (11) where kp (mg g-1 min-1/2) is the intra-particle diffusion rate constant and C (mg g-1) is a constant providing information about the thickness of boundary layer. The computations of
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ACCEPTED MANUSCRIPT constants of kinetic models were done by non-linear regression using SigmaPlot 12.0 software. The goodness of the fit and best model was discussed using R2 and RMSE. 2.6. Biosorption thermodynamics As a significant thermodynamic parameter, the change of standard Gibbs free energy (ΔG°) was calculated to explore the suitability, spontaneity and nature of MG biosorption.
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The value of ΔG° can be estimated by [27]:
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G RT ln KD …………………….. (12)
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where KD (Cs/Ce) is the distribution coefficient. Cs and Ce (mg L-1) are the equilibrium dye concentrations on biosorbent and in solution, respectively.
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2.7. Characterization
Scanning electron microscopy (SEM, Zeiss Evo Ls 10) was used to reveal the surface
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structure of modified biosorbent. The infrared spectra of biosorbent before and after the dye biosorption were obtained using PerkinElmer Fourier transform infrared spectrometer (FTIR,
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3. Results and discussion
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Spectrum 400) to identify the possible effective active sites for MG biosorption.
3.1. Effect of contact time
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Fig. 1(a) presents the effect of contact time on the biosorption of MG onto the modified biosorbent. The biosorption capacity of biosorbent significantly increased within the first 60
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min and slowly reached to equilibrium within 120 min. Further extending the contact time did not improve the biosorption potential of biosorbent for MG. The initial high rate might relate to the large numbers of available sites on the surface of biosorbent and the subsequently decreased biosorption rate was probably due to gradual occupancy of those free binding sites [7, 10]. 3.2. Effect of MG concentration
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ACCEPTED MANUSCRIPT The response of MG biosorption onto the biosorbent as a function of dye concentration is shown in Fig. 1(b). As the initial MG concentration increased from 10 to 30 mg L-1, the biosorption capacity increased from 17.879 to 52.525 mg g-1. This trend might be due to the increase in the necessary driving force to overcome the resistances to the mass transfer of MG between the aqueous and solid stages [28].
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3.3. Effect of pH
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The medium pH is a critical parameter in biosorption system. It strongly affects the surface
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charge of biosorbent, the degree of ionization and the speciation of biosorbates (e.g., dye, metal). The effect of solution pH on the biosorption of MG was studied initially in the pH
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range of 4-8. The removal of dye by the biosorbent increased significantly with an increase in the solution pH as seen in Fig. 1(c). This was purely due to the involvement of ionic
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interactions in the biosorption process. Since the surface charge of biosorbent is positive at lower pH, the competitive effects of the surrounding H+ ions as well as electrostatic repulsion
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between the dye cation and the positively charged active biosorption sites on the surface of
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biosorbent lead to a decrease in the dye removal. In contrast, at higher pH, the biosorbent surface has a negative charge leading to rising cationic MG biosorption due to electrostatic
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attraction forces [1].
3.4. Effect of biosorbent loading
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The biosorbent amount is a significant parameter as it determines the biosorption capacity for a given pollutant concentration. The biosorbent quantity was studied in the range of 10-30 mg and the response graph is displayed in Fig. 1(d). The biosorption capacity observed higher at lower biosorbent amount. This behavior could be explained by the partial aggregation of biomass resulting in a lower effective surface area [7, 29]. 3.5. Isotherm studies
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[7, 10]. Hence, Freundlich, Langmuir, Sips and Dubinin-Radushkevich isotherm models were
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employed to describe the biosorption equilibrium characteristics of MG bioremediation. The
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biosorption isotherms for MG biosorption onto the biosorbent are given in Fig. 2 and the related parameters are listed in Table 1. In view of the results presented in the figure and
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table, Sips model had the best fitting to the experimental data for MG biosorption, evidenced by the values of R2 and RMSE. Sips isotherm model incorporates the features of Langmuir
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and Freundlich equations. The heterogeneity factor of nS close to or even 1 shows biosorbent with comparatively homogenous binding sites, while nS close to 0 displays heterogeneous
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biosorbent. This constant was calculated to be 0.140, which implied that the model looked
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more like Freundlich model than Langmuir model for the biosorption of MG onto the relatively heterogeneous surface of biosorbent [9]. In addition, the biosorption capacity of
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modified biosorbent was comparable with those of other biosorbents reported in literature for MG removal [30-32]. This highlighted its potential usage for unsafe MG dye removal as an
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effective, low cost and ecological friendly biosorbent. The equilibrium parameter or separation factor (RL) obtained from Langmuir model executed favorable dye biosorption [10]. From Freundlich isotherm, the value of nF constant, falling in the range of 1-10 also showed a suitable biosorption process [7]. The free energy of biosorption, E (kJ mol-1), obtained from Dubinin-Radushkevich model is usually applied to distinguish the nature of biosorption. When the value of E, is in the range 816 kJ mol-1, the biosorption process is a chemical ion exchange process, while for E value < 8
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ACCEPTED MANUSCRIPT kJ mol-1, the biosorption mechanism occurs through a physical process [33]. According to the E value obtained for the present study, the biosorption of MG seems to involve physical mechanism. 3.6. Kinetic and mechanism studies The determination of operational and kinetic parameters is important in the biotreatment of
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wastewater as it provides us valuable insights into the biosorption reaction mechanism. In this
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study, the pseudo-first-order, pseudo-second-order, Elovich, logistic and intra-particle diffusion models were applied to interpret the biosorption kinetic data. The kinetic constants
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and statistical analysis data are demonstrated in Table 2. Fig. 3(a-c). The values of R2 and
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RMSE from the table revealed that the biosorption process was better described by the logistic equation than the other models. In addition, the estimated biosorption capacity of
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biosorbent for MG by the logistic model was very close to the experimental one. These findings showed that the logistic model was preferable for the biosorption of MG onto the
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modified biosorbent. On the other hand, the intra-particle diffusion model was used to identify
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the possible mechanism(s) involved in the biosorption process. The intra-particle diffusion plots are illustrated in Fig. 3(d) for MG biosorption. As shown in the figure, the straight lines
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did not go through the origin, indicating that the pore diffusion was not the only ratecontrolling step [9, 33]. This suggested that the surface biosorption and intra-particle diffusion
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might contribute to the biosorption of MG onto the modified biosorbent. 3.7. Thermodynamic studies In engineering practice, values of thermodynamic parameters like the standard free energy change of Gibbs (ΔG°) should be taken into consideration in order to determine the spontaneity, feasibility and nature of biosorption process. The biosorption free energy change was calculated using Eq. (12) and the obtained values were -1.494, -1.701 and -2.877 kJ mol-1 for MG concentrations of 10, 20 and 30 mg L-1. The change of Gibbs free energy for physical
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ACCEPTED MANUSCRIPT biosorption is in the range of 0 to -20 kJ mol-1, while for chemical biosorption, it is in the range of -80 to -400 kJ mol-1 [34]. The negative ΔG° value showed that this biosorption process was spontaneous, feasible and physical in the studied temperature. 3.8. Characterization studies The SEM images obtained before and after MG biosorption onto the modified biosorbent
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are showed in Fig. 4. The biosorbent possessed heterogeneous surface morphology. After the
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biosorption of dye, this structure was covered with MG molecules. On the other hand, the FTIR spectra before and after the biosorption of dye are given in Fig. 5. The strong and broad
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band at around 3333 cm-1 is attributed to O-H stretching vibration [35]. The peak at around
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2891 cm-1 is assigned to the stretching vibration of C-H [36]. The bands observed between 1750 and 1500 cm-1 correspond to C=O and C=C stretching vibrations [15]. The peaks
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between 1460 and 1300 cm-1 refer to the bending vibrations of O-H and C-H groups [15, 37]. The bands appeared between 1300 and 1100 cm-1 are attributed to C-O stretching vibration
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[38]. A strong peak at around 1027 cm-1 is ascribed to C-O-C stretching [39]. The bands seen
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between 900 and 800 cm-1 are due to the bending vibration of C-H [12, 15]. The band shifts after the dye loading revealed that various chemical groups particularly observed at around
4. Conclusions
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3333, 2891, 1736, 1598, 1372, 1314, 1263 and 893 cm-1 might contribute to MG biosorption.
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The CTAB modified multi-component biosorbent is a potential biosorption agent for the removal of MG from aqueous solution. The biosorption process was affected by the medium pH, biosorbent quantity, reaction time and MG concentration. The biosorption data fitted well with Sips and the logistic models, and the maximum biosorption capacity was 52.610 mg g-1. The pore diffusion and surface biosorption were the main mechanisms involved in dye removal. This natural biosorbent can be a good candidate to remediate water bodies polluted with such hazardous dyes.
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ACCEPTED MANUSCRIPT References [1] K.Y. Hor, J.M.C. Chee, M.N. Chong, B. Jin, C. Saint, P.E. Poh, R. Aryal, Evaluation of physicochemical methods in enhancing the adsorption performance of natural zeolite as lowcost adsorbent of methylene blue dye from wastewater, J. Clean. Prod., 118 (2016) 197-209. [2] S.C.R. Santos, R.A.R. Boaventura, Adsorption of cationic and anionic azo dyes on
PT
sepiolite clay: Equilibrium and kinetic studies in batch mode, J. Environ. Chem. Eng., 4
RI
(2016) 1473-1483.
SC
[3] F. Deniz, Color removal from aqueous solutions of metal-containing dye using pine cone, Desalin. Water Treat., 51 (2013) 4573-4581.
NU
[4] S. Torbati, Artificial neural network modeling of biotreatment of malachite green by Spirodela polyrhiza: Study of plant physiological responses and the dye biodegradation
MA
pathway, Process Saf. Environ. Prot., 99 (2016) 11-19.
[5] A.A. El-Zahhar, N.S. Awwad, Removal of malachite green dye from aqueous solutions
D
using organically modified hydroxyapatite, J. Environ. Chem. Eng., 4 (2016) 633-638.
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[6] Z.-z. Lin, H.-y. Zhang, A.-h. Peng, Y.-d. Lin, L. Li, Z.-y. Huang, Determination of malachite green in aquatic products based on magnetic molecularly imprinted polymers, Food
CE
Chem., 200 (2016) 32-37.
[7] Z. Hajahmadi, H. Younesi, N. Bahramifar, H. Khakpour, K. Pirzadeh, Multicomponent
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isotherm for biosorption of Zn(II), Co(II) and Cd(II) from ternary mixture onto pretreated dried Aspergillus niger biomass, Water Resour. Ind., 11 (2015) 71-80. [8] F. Deniz, Adsorption properties of low-cost biomaterial derived from Prunus amygdalus L. for dye removal from water, Sci. World J., Article ID 961671 (2013). [9] S. Amirnia, M.B. Ray, A. Margaritis, Copper ion removal by Acer saccharum leaves in a regenerable continuous-flow column, Chem. Eng. J., 287 (2016) 755-764.
14
ACCEPTED MANUSCRIPT [10] J. Huang, D. Liu, J. Lu, H. Wang, X. Wei, J. Liu, Biosorption of reactive black 5 by modified Aspergillus versicolor biomass: Kinetics, capacity and mechanism studies, Colloids Surf., A, 492 (2016) 242-248. [11] F. Deniz, Optimization of biosorption conditions for color removal by Taguchi DOE Methodology, Environ. Prog. Sustain. Energy, 32 (2013) 1129-1133.
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[12] S. Benyoucef, M. Amrani, Adsorption of phosphate ions onto low cost Aleppo pine
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adsorbent, Desalination, 275 (2011) 231-236.
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[13] L. Semerjian, Equilibrium and kinetics of cadmium adsorption from aqueous solutions using untreated Pinus halepensis sawdust, J. Hazard. Mater., 173 (2010) 236-242.
NU
[14] X.-T. Zhao, T. Zeng, Z.J. Hu, H.-W. Gao, C.Y. Zou, Modeling and mechanism of the adsorption of proton onto natural bamboo sawdust, Carbohydr. Polym., 87 (2012) 1199-1205.
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[15] D. Sidiras, F. Batzias, E. Schroeder, R. Ranjan, M. Tsapatsis, Dye adsorption on autohydrolyzed pine sawdust in batch and fixed-bed systems, Chem. Eng. J., 171 (2011) 883-
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896.
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[16] T. Zhou, W. Lu, L. Liu, H. Zhu, Y. Jiao, S. Zhang, R. Han, Effective adsorption of light green anionic dye from solution by CPB modified peanut in column mode, J. Mol. Liq., 211
CE
(2015) 909-914.
[17] A. Hassani, A. Khataee, S. Karaca, M. Karaca, M. Kıranşan, Adsorption of two cationic
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textile dyes from water with modified nanoclay: A comparative study by using central composite design, J. Environ. Chem. Eng., 3 (2015) 2738-2749. [18] H.M.F. Freundlich, Over the adsorption in solution, Z. Phys. Chem., 57 (1906) 385-470. [19] I. Langmuir, The adsorption of gases on plane surfaces of glass, mica and platinum, J. Am. Chem. Soc., 40 (1918) 1361-1403. [20] R. Sips, On the structure of a catalyst surface, J. Chem. Phys., 16 (1948) 490-495.
15
ACCEPTED MANUSCRIPT [21] M.M. Dubinin, L.V. Radushkevich, Equation of the characteristic curve of activated charcoal, Proc. Acad. Sci. Phys. Chem. Sec. USSR, 55 (1947) 331-333. [22] S. Lagergren, About the theory of so-called adsorptıon of soluble substances, K. Sven. Vetenskapsakad. Handl., 24 (1898) 1-39. [23] Y.-S. Ho, Review of second-order models for adsorption systems, J. Hazard. Mater., 136
PT
(2006) 681-689.
RI
[24] S. Chien, W. Clayton, Application of Elovich equation to the kinetics of phosphate release and sorption in soils, Soil Sci. Soc. Am. J., 44 (1980) 265-268.
SC
[25] L. Hu, K. Tian, X. Wang, J. Zhang, The “S” curve relationship between export diversity
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and economic size of countries, Physica A, 391 (2012) 731-739. [26] W.J. Weber, J.C. Morris, Kinetics of adsorption on carbon from solution, J. Sanit. Eng.
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Div. Am. Soc. Civ. Eng., 89 (1963) 31-60.
[27] K.Y. Foo, B.H. Hameed, Insights into the modeling of adsorption isotherm systems,
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Chem. Eng. J., 156 (2010) 2-10.
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[28] M. Foroughi-dahr, H. Abolghasemi, M. Esmaieli, G. Nazari, B. Rasem, Experimental study on the adsorptive behavior of Congo red in cationic surfactant-modified tea waste,
CE
Process Saf. Environ. Prot., 95 (2015) 226-236. [29] M. Iqbal, N. Iqbal, I.A. Bhatti, N. Ahmad, M. Zahid, Response surface methodology
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application in optimization of cadmium adsorption by shoe waste: A good option of waste mitigation by waste, Ecol. Eng., 88 (2016) 265-275. [30] Z. Bekçi, Y. Seki, L. Cavas, Removal of malachite green by using an invasive marine alga Caulerpa racemosa var. cylindracea, J. Hazard. Mater., 161 (2009) 1454-1460. [31] S. Chowdhury, R. Mishra, P. Saha, P. Kushwaha, Adsorption thermodynamics, kinetics and isosteric heat of adsorption of malachite green onto chemically modified rice husk, Desalination, 265 (2011) 159-168.
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ACCEPTED MANUSCRIPT [32] M. Rajabi, B. Mirza, K. Mahanpoor, M. Mirjalili, F. Najafi, O. Moradi, H. Sadegh, R. Shahryari-ghoshekandi, M. Asif, I. Tyagi, S. Agarwal, V.K. Gupta, Adsorption of malachite green from aqueous solution by carboxylate group functionalized multi-walled carbon nanotubes: Determination of equilibrium and kinetics parameters, J. Ind. Eng. Chem., 34 (2016) 130-138.
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[33] P.S. Blanes, M.E. Bordoni, J.C. González, S.I. García, A.M. Atria, L.F. Sala, S.E. Bellú,
RI
Application of soy hull biomass in removal of Cr(VI) from contaminated waters. Kinetic,
SC
thermodynamic and continuous sorption studies, J. Environ. Chem. Eng., 4 (2016) 516-526. [34] M. Gholami, M.T. Vardini, G.R. Mahdavinia, Investigation of the effect of magnetic
NU
particles on the Crystal Violet adsorption onto a novel nanocomposite based on κcarrageenan-g-poly(methacrylic acid), Carbohydr. Polym., 136 (2016) 772-781.
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[35] M.S. Rahman, M.R. Islam, Effects of pH on isotherms modeling for Cu(II) ions adsorption using maple wood sawdust, Chem. Eng. J., 149 (2009) 273-280.
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[36] M.A. Wahab, S. Jellali, N. Jedidi, Ammonium biosorption onto sawdust: FTIR analysis,
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kinetics and adsorption isotherms modeling, Bioresour. Technol., 101 (2010) 5070-5075. [37] O.M. Paska, C. Pacurariu, S.G. Muntean, Kinetic and thermodynamic studies on
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methylene blue biosorption using corn-husk, RSC Adv., 4 (2014) 62621-62630. [38] A. Ahmad, M. Rafatullah, O. Sulaiman, M.H. Ibrahim, R. Hashim, Scavenging
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behaviour of meranti sawdust in the removal of methylene blue from aqueous solution, J. Hazard. Mater., 170 (2009) 357-365. [39] R.K. Gautam, P.K. Gautam, S. Banerjee, V. Rawat, S. Soni, S.K. Sharma, M.C. Chattopadhyaya, Removal of tartrazine by activated carbon biosorbents of Lantana camara: Kinetics, equilibrium modeling and spectroscopic analysis, J. Environ. Chem. Eng., 3 (2015) 79-88.
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ACCEPTED MANUSCRIPT List of Figures Fig. 1. Effects of contact time (a), dye concentration (b), pH (c) and biosorbent quantity (d). Fig. 2. Isotherm models. Fig. 3. Kinetic models for MG concentrations of 10 (a), 20 (b), 30 mg L-1 (c) and intra-particle diffusion plots (d).
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Fig. 4. SEM images of biosorbent before (a) and after (b) MG biosorption.
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Fig. 5. FTIR spectra of biosorbent before (a) and after (b) MG biosorption.
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ACCEPTED MANUSCRIPT Table 1. Biosorption isotherm parameters. Parameter
Value
Freundlich
KF (mg g-1 (L mg-1)1/nF)
4.968
nF (-)
1.369
R2
0.9653
RMSE
3.626
qm (mg g-1)
55.688
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KL (L mg-1)
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0.024
RL (-)
0.808
R2
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0.9429
RMSE
nS (-)
0.140
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1.0000
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52.610
KS (L mg-1)1/nS
R2
Dubinin-Radushkevich
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qm (mg g-1)
Sips
4.182
RMSE
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qm (mg g-1)
63.193
E (kJ mol-1)
0.001
R2
0.8826
RMSE
8.574
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ACCEPTED MANUSCRIPT Table 2. Biosorption kinetic data. Model
MG concentration (mg L-1)
Parameter
10
20
30
qe (mg g-1)
18.203
39.797
46.657
order
k1 (min-1)
0.026
0.032
0.044
R2
0.9652
0.8875
0.7115
RMSE
1.102
4.124
7.506
Pseudo-second-
qe (mg g-1)
23.255
47.699
order
k2 (g mg-1 min-1)
0.001077
R2
0.9765
RMSE
0.906
α (mg g-1 min-1)
3.421
51.014 0.001358
0.9198
0.8059
3.480
6.157
7.000
7.915
0.292
0.143
0.126
0.9128
0.8826
0.8729
1.744
4.211
4.981
qe (mg g-1)
17.629
41.194
53.661
kL (min-1)
0.055
0.047
0.037
tc (min)
29.771
27.501
25.752
R2
0.9736
0.9891
0.9899
RMSE
1.036
1.384
1.520
Intra-particle
C (mg g-1)
0.120
3.091
8.099
diffusion
kp (mg g-1 min-1/2)
1.712
3.570
4.060
R2
0.9908
0.9951
0.9953
RMSE
0.566
0.860
0.956
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β (g mg-1)
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Elovich
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0.001200
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Fig. 4. SEM images of biosorbent before (a) and after (b) MG biosorption.
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Fig. 5. FTIR spectra of biosorbent before (a) and after (b) MG biosorption.
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ACCEPTED MANUSCRIPT Research highlights: A mix biosorbent composed of different sawdust biomasses. Application of CTAB modified biosorbent for biotreatment of Malachite green.
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A good candidate to remediate water bodies polluted with such hazardous dyes.
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