Shahla Elhami 1, *, Maryam Abrishamkar 1 and Ladan Esmaeilzadeh 2 1. ELHAMI et al: PREPARATION AND CHARACTERIZATION OF DETA

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1 ELHAMI et al: PREPARATION AND CHARACTERIZATION OF DETA Journal of Scientific & Industrial Research Vol. 72, July 2013, pp Preparation and Characterization of Diethylentriamine-montmorillonite and its application for the removal of Eosin Y dye:optimization, Kinetic and Isotherm studies Shahla Elhami 1, *, Maryam Abrishamkar 1 and Ladan Esmaeilzadeh 2 1 *Department of Chemistry, Science and Research Branch, Islamic Azad University, Khouzestan, Iran. 2 Young Researchers Club, Khouzestan Science and Research Branch, Islamic Azad University, Ahvaz, Iran Received 27 July 2012; revised 31 December 2012; accepted 30 April 2013 The adsorption capacity regarding anionic dye is low on Montmorillonite which is a common nanoclay mineral with a permanent negative structural charge. A novel montmorillonite-based composite was applied for the removal of anionic dye from aqueous solution. A facile one-step method was employed to produce diethylentriamine-montmorillonite (DETA-MMT) composit. The structural and morphological study of the synthesized composite was then carried out by fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Adsorption characteristics of DETA-MMT were examined by using eosin Y (EY) dye as an anionic dye. The effects of several parameters such as ph value of the dye solution, adsorbent dose, adsorption time and the initial dye concentration on the EY adsorption onto the composite were investigated. DETA-MMT had a high uptake capacity in room temperature and could remove Eosin dye of about 90 % with 8 g/l of adsorbent in only 5 min. Langmuir and Freundlich isotherms were employed for the study of the adsorption of EY dye onto DETA-MMT which revealed that adsorption kinetics of EY dye onto the composite followed the pseudo-second-order kinetic model. The method was applied to the removal of EY dye in tap water and river water samples from different parts of Khouzestan, Iran. Keywords: Montmorillonite, Removal, Eosin Y, Kinetic, Isotherm. Introduction The removal of dyes from wastewater is considered to be an important application of adsorption process using suitable adsorbent. Various kinds of adsorbents have been reported such as activated carbon 1, zeolite 2, fly ash 3, chitosan 4 and by-products from juice processing 5. The clay minerals play an important role in the environment by acting as a natural scavenger of pollutants from water through both ion exchange and adsorption mechanisms 6. The high specific surface area, chemical and mechanical stability, layered structure, high cation exchange capacity, etc., have made the clays excellent adsorbent materials 7. Montmorillonite is smectitic clay with a permanent negative structural charge; therefore, it has a low adsorption capacity with respect to anionic dyes. It is well known that the negative charge of montmorillonite (MMT) is balanced by exchangeable cations which are usually Na + and Ca 2+. It is possible to modify the surface *Author for correspondence Sh.elhami@khouzestan.Srbiau.ac.ir properties of MMT greatly by replacing the natural inorganic cations with other ones such as metal ions 8 and quaternary ammonium ions 9. The modification process may induce an enormous change in the surface and pore structures of MMT and hence mediate the practical applications of clays as adsorbents or catalysts. Eosin Y (EY), anionic dye, is widely used in various fields such as dyeing, printing, leather, printing ink and fluorescent pigment 10. Several methods have been studied for removal of EY dye from aqueous solutions: photooxidation 11, oxidation by the solar photo-fenton processes 12, cloud point extraction 13, solvent extraction using reverse micelles 14 and adsorption 10, In this study, MMT modified with diethylentriamine (DETA) was successfully synthesized via a facial onestep method and then char acterized by FT-IR spectroscopy and SEM techniques. Afterward, the synthesized composite was used for removal of anionic eosin (EY) dye from water samples. The effects of ph value of the dye solution, adsorbent dose, adsorption time and the initial dye concentration on the adsorption of EY dye on DETA-MMT have been investigated. The

462 J SCI IND RES VOL 72 JULY 2013 Fig. 1 SEM images of MMT (a) DETA-MMT (b) and DETA-MMT after EY dye adsorption (c) at 15000 times magnifications 100 Removal (%) 95 90 85 2 3 4 ph 5 6 Fig.

2 462 J SCI IND RES VOL 72 JULY 2013 Fig. 1 SEM images of MMT (a) DETA-MMT (b) and DETA-MMT after EY dye adsorption (c) at times magnifications 100 Removal (%) ph 5 6 Fig. 2 Effect of ph on EY dye removal (initial dye concentration 100 mg/l, adsorbent dosage=0.3 g/50 ml, temperature 25 C, contact time=30 min, agitation rate= 120 rpm). Langmuir and Freundlich isotherms and adsorption kinetics of EY dye onto DETA-MMT were also studied, and the mechanism of EY dye adsorption was fully discussed. Experimental Section Material All chemicals used wer e of analytical grade and were used as received. Also, doubled distilled water was used throughout the study. Montmorillonite (sodium form) was supplied by F.C.C. (china). A stock solution of 1000 mg/l of EY dye was prepared by dissolving 0.50 g of the reagent (Merck) in water and diluting to as much as 500 ml in a volumetric flask. The desired concentrations were obtained by successive dilutions. Preparation of adsorbent The montmorillonite (5 g) was suspended in 500 ml distilled water and stirred magnetically for about 24 h at room temperature. Then, 5 ml DETA was added and the ph of the solution was adjusted to 3.5 using hydrochloric acid. The suspension was stirred for 2 h in 50 o C. The white precipitation was filtered and washed several times with double distilled water. In the end, the precipitation was dried in an oven at 50 C for 48 h. Results and Discussion Adsorbent characterization SEM photographs study The surface morphologies of the MMT, DETA- MMT and DETA-MMT after adsorption of EY dye were studied using scanning electron microscopy. Micrographs of the surface of each material are shown in Fig. 1(a) (c) at times magnifications. They are typical of the overall surface of each sample. Fig. 1(a) corresponds to the raw MMT which shows that MMT consists of small particles and has a nonporous surface; however, it was not compact. After the fabrication of the DETA-MMT composite, as it is presented in Fig 1(b), the sharp sheet could not be observed anymore due to the coating of DETA onto the surfaces of MMT. The SEM image before dye sorption revealed the round surface texture and heterogeneous porosity. As shown in Fig. 1(c), DETA-MMT presented a smooth surface texture after

3 ELHAMI et al: PREPARATION AND CHARACTERIZATION OF DETA 463 dye sorption which suggested that the dye molecules were trapped into the pores and homogeneously sorbed on its surface. FT-IR Spectroscopic Study The FT-IR spectra of MMT and DETA-MMT studied. Specifically, the peak at 3630 cm -1 is attributed to clay lattice OH stretching vibrations while those at 3448 and 1639 cm -1 are attributed to the adsorbed H2O deformation21. Comparing the FT-IR spectra of MMT and DETA-MMT, the band at 1639 cm -1 (the FT-IR spectra of MMT) showed a shift to 1632 cm -1 (the FT- IR spectra of DETA-MMT). The FT-IR spectrum of DETA-MMT indicated the presence of a new band at about 3033 cm -1 corresponding to the N-H stretching absorption band. These results confirmed that the MMT was modified by DETA. The effect of ph The adsorption of EY dye onto the composite as a function of ph was investigated at the initial dye concentration of 100 mg/l and the contact time of 30 min. The investigations were carried out at ph upper than 3 due to the precipitation of EY dye under acidic conditions at ph values lower than 2. The effect of ph on the adsorption of EY dye onto composite is shown in Fig. 2. The removal of Eosin Y was maximum in the ph of 4.0. In the acidic solution, the adsorption process of the Eosin Y, anionic dye, by DETA-MMT is an electrostatic interaction in which the protonated amine groups of DETA-MMT interact with the anionic groups of the dye. While at higher ph values, more OH - ions exist and compete with the anionic bromide groups of Eosin Y for the adsorption sites of adsorbent, thus the available adsorption sites for anionic EY decrease dramatically 10. Effect of adsorbent dose The influence of adsorbent dose on EY dye removal was studied by varying the adsorbent dose from 1.0 to 10.0 g/l at an initial EY dye concentration of 100 mg/l in 50 ml solutions. Increased adsorbent dosage implied a greater surface area and a greater number of binding sites available for the constant amount of EY dye. An adsorbent dose of 8 g/l was chosen as an optimum value. The results showed that 6 g/l of DETA-MMT is required for the 96% remova l of EY dye from initial concentrations of 100 mg/l while Ansari R. et al. reported that the adsorbent dose required for other procedure using coated sawdust with polymer is 16 g/l for removal of 50 mg/l eosin 10 and using activated carbon Removal (%) Contact time (min) Fig. 3 Effect of contact time on adsorption of EY dye (adsorbent dosage=0.4 g/50 ml, ph=4.0, temperature=25 C, agitation rate= 120 rpm). is 1.0 g/l to remove 100 mg/l EY 18. Although the dose of activated carbon adsorbent is less than modified montmorillonite but using activated carbon will lead to high cost. Effect of contact time and Agitation Rate The adsorption of EY dye onto composite adsorbent has been investigated as a function of time in the range of 2-40 min, as it is demonstrated in Fig. 3. In each adsorption experiment, 50 ml of dye solution of known concentration and ph was added to 0.4 g of the adsorbent in 50 ml round bottom flask at room temperature and the mixture was stirred on a shaker at 120 rpm. As the results indicated, removal of EY dye using the DETA- MMT adsorbent occurred quickly and it was not a highly time-dependent process. It was found that about 90% removal of EY dye occurs within 5 min. However, for a removal of about 95%, a time interval of 30 minutes was needed. This confirms a high and rapid adsorption of EY dye by DETA-MMT. The results were better than those of the most widely adsorption method reported previously for the removal of EY dye 10, 15-17, 19-20, except for the adsorption method using carbon active 18 which showed a more satisfactory removal for EY dye in the aqueous media. The agitation speed was also surveyed ranging between 50 and 140 rpm. During all agitation speeds the removal was not varied significantly. An agitation speed of 80 rpm was, therefore, chosen as an optimum value. Initial concentration In all the cases of optimization, the concentration of dye was 100 mg/l. In order to study the possibility of

4 464 J SCI IND RES VOL 72 JULY /q e y = 0.863x R 2 = /c e Fig. 4 The plot of EY dye adsorption on Langmuir isotherm model dye removal in other concentrations with the same optimization condition, other concentrations were studied as well. The results showed that the optimization condition was applicable for concentrations from 30 to 500 mg/l with dye removal being 93-99%. For concentrations up to 500 ppm, EY quantitative removal (>98%) was achieved. Interference study The effect of various ions as potential interference on the removal of EY dye was also investigated. Known concentrations of potential interfering ions were added to a solution containing 100 mg/l of EY and the solution was analyzed by the proposed method. The tolerance limit of each foreign ion substance was taken as largest concentrations yielding an error of less than ±5%. Each of the ions in different concentrations was investigated. The results showed that Zn 2+, Pb 2+, Ni 2+, Na +, Mg 2+, BrO, CH 3 3 COO -, Cd 2+, Br -, K +, Cl -, NH 4+, Fe 3+, Cu 2+, Sn 2+ and NO are tolerable up to 100 mg/l whereas 3 Cr 6+ showed a tolerance up to 50 mg/l. The interference of some dyes was also studied. The results showed that malachite green, crystal violet, methylene blue, methyl orange, rodamine B and alizarin yellow are tolerable up to 100ppm. The tolerance levels of some metal ions and dyes are suitable for removal of EY dye from real sample. Application In order to test the reliability of the proposed removal methodology, it was applied to the remova l of concentrations of EY dye from tap water and river water samples from different parts of Khouzestan, Iran. For Table 1 Removal of eosin Y in spiked water samples Sample Eosin Y added Eosin Y found Extraction (mg/l) after removal efficiency (%) (mg/l) Tap water ± ± ± River water ± ± ± a x ± ts/ n at 95% confidence (n = 5), ph of all samples adjusted in 4 using nitric acid. this purpose, 15 ml of each sample was treated under the general procedure. Spiking EY dye to the samples performed the validity of the procedure. The results presented in Table 1 indicated that good extraction efficiencies were obtained for the removal of EY dye spiked to river and tap water samples. Isotherms of Adsorption In this study, Langmuir and Freundlich isotherms were employed for the study of the adsorption of EY dye onto modified montmorillonite. Such isotherms were achieved for an initial concentration of mg/l in the previous optimization condition and a temperature of 25±2 0 C. Langmuir Isotherm In order to study the adsorption of dye according to Langmuir Isotherm 22 a plot of 1/q e versus 1/C e was

5 ELHAMI et al: PREPARATION AND CHARACTERIZATION OF DETA 465 Table 2 Isotherm parameters for the removal of EY dye on DETA-MMT Isotherm Parameters Values Langmuir q m (mg/g) 10.6 K a (L/mg) 0.11 R Freundlich K F 1.9 n 0.46 R drawn. Langmuir constants are shown in Fig. 4 and Table 2. Freundlich Isotherm The Freundlich model assumes a heterogeneous adsorption surface with sites that have different adsorption energies which are not equally available 23. For this isotherm, log q e was plotted versus log C e. The results were presented in Table 2. Adsorption kinetic studies The adsorption was considered as the pseudo-firstorder and pseudo-second-order kinetic models 24, 25. Parameters for pseudo-first and pseudo-second order models from liner regression for concentrations of 50 and 100 (mg/l) of EY are summarized in Table 3. According to Table 3, the adsor ption kinetics well fitted using a pseudo second-order kinetic model. Conclusion The present investigation evaluated the fact that the chemically modified montmorillonite with diethylenetriamine can be used as an effective adsorbent for the removal of EY dye, anionic dye, from different water samples. The SEM images clearly showed that after the chemical treatment, a lot of pores were produced and the FT-IR spectra showed that a chemical modification was successfully occurred. Contact time, adsorbent dosage and ph are the most effective parameters on adsorption of dyes. The effects of these parameters on the adsorption of EY dye were examined applying optimal experimental conditions. From the experimental results, it was found out that for dye concentrations ranging mg/l, quantitative removal (more than 93%) was obtained in a single adsorption. In the kinetics study, pseudo-first order and pseudo-second order were tested; the latter equation showed the best repr esent the experimental data. Table 3 Kinetic parameters for the removal of EY dye Kinetic parameters 50 (mg/l) 100 (mg/l) q e, exp (mg/g) Pseudo- First -order equation K 1 (min -1 ) q e (mg/g) R Pseudo-second-order equation K 2 (g/mg min) q e (mg/g) R Acknowledgment The authors wish to thank Science and Research Branch, Islamic Azad University, Khouzestan for financially supporting this study. References 1 Pandharipande S L, Urunkar Y D & Singh A, Reduction of COD and Chromium, and decolourisation of tannery wastewater by activated carbons from agro-wastes, J Sci Ind Res, 71 (2012) Armaan B, Özdemir O, Turan M & Çelik M, The removal of reactive azo dyes by natural and modified zeolites, J Chem Technol Biot, 78 (2003) Mall I D, Srivastava V C & Agarwal N K, Removal of Orange-G and Methyl Violet dyes by adsorption onto bagasse fly ash kinetic study and equilibrium isotherm analyses, Dyes Pigments, 69 (2006) Bhuvaneshwari S, Sruthi D, Sivasubramanian V & Kanthimathy K, Regeneration of chitosan after heavy metal sorption, J Sci Ind Res, 71 (2012) Jain R & Sikarwar Sh, Removal of hazardous dye congored from waste material, J Hazard Mater, 152 (2008) Ling H, Lu A, Wang C, Li Y, Chen P, Zhou J & Wang J, Treatment of Municipal Landfill Leachate with Organically Modified Bentonite, Clays Clay Miner, 59 (2011) Gupta S S & Bhattacharyya K G, Removal of Cd(II) from aqueous solution by kaolinite, montmorillonite and their poly(oxo zirconium) and tetrabutylammonium derivatives, J Hazard Mater, 128 (2006) Morodome Sh & Kawamura K, In Situ X-ray Diffraction Study of the Swelling of Montmorillonite as Affected by Exchangeable Cations and Temperature, Clays Clay Miner, 59 (2011) Wang Y, Wang X, Duan Y, Liu Y & Du Sh, Modification of Montmorillonite with Poly(oxypropylene)amine hydrochlorides: Basal Spacing, Amount intercalated, and Thermal Stability, Clays Clay Miner, 59 (2011) Ansari R & Mosayebzadeh Z, Removal of Eosin Y, an Anionic Dye, from Aqueous Solutions Using Conducting Electroactive Polymers, Iran Polym J, 19 (2010) Poulios I, Micropoulou E, Panou R & Kostopoulou E, Photooxidation of eosin Y in the presence of semiconducting oxides, Appl Catal B-Environ, 41 (2003)

6 466 J SCI IND RES VOL 72 JULY Zheng H, Pan Y & Xiang X, Oxidation of acidic dye Eosin Y by the solar photo-fenton processes, J Hazard Mater, 141 (2007) Purkait M K, Banerjee S, Mewara S, DasGupta S & De S, Cloud point extraction of toxic eosin dye using Triton X-100 as nonionic surfactant, Water Res, 39 (2005) Pandit P & Basu S, Removal of Ionic Dyes from Water by Solvent Extraction Using Reverse Micelles, Environ Sci Technol, 38 (2004) Chatterjee S, Chatterjee B P, Das A R & Guha A K, Adsorption of a model anionic dye, eosin Y, from aqueous solution by chitosan hydrobeads, J Colloid Interf Sci, 288 (2005) Du W L, Xu Z R, Han X Y, Xu Y L & Miao Z G, Preparation, characterization and adsorption properties of chitosan nanoparticles for eosin Y as a model anionic dye, J Hazard Mater, 153 (2008) Kang Q, Zhou W, Li Q, Gao B, Fan J & Shen D, Adsorption of anionic dyes on poly(epicholorohydrindimethylamine) modified bentonite in single and mixed dye solutions, Appl Clay Sci, 45 (2009) Purkait M K, Gupta S D & De S, Adsorption of eosin dye on activated carbon and its surfactant based desorption, J Environ Manage, 76 (2005) Huanga X, Binb J, Buc H, Jianga G & Zengd M, Removal of anionic dye eosin Y from aqueous solution using ethylenediamine modified chitosan, Carbohyd Polym, 84 (2011) Porkodi K & Kumar K V, Equilibrium, kinetics and mechanism modeling and simulation of basicand acid dyes sorption onto jute fiber carbon: Eosin yellow, malachitegreen and crystal violet single component systems, J Hazard Mater, 143 (2007) Balomenou G, Stathi P, Enotiadis A, Gournis D & Deligiannakis Y, Physicochemical study of amino-functionalized organosilicon cubes intercalated in montmorillonite clay: H-binding and metal uptake, J Colloid Interf Sci, 325 (2008) Langmuir I, The constitution and fundamental properties of solids andliquids, J Am Chem Soc, 38 (1916) Freundlich H.M.F, Die adsorption in losungen, Zeitschrift fur Physikalische Chemie, 57(1906) Lagergren S, About the theory of so-called adsorption of soluble substances, 24 (1898) Ho YS & McKay G, pseudo-second order model for sorption processes, Proc Biochem, 34 (1999)

Received: 24 th April-2012 Revised: 07 th May-2012 Accepted: 10 th May-2012 Research article

Received: 24 th April-2012 Revised: 07 th May-2012 Accepted: 10 th May-2012 Research article EQUILIBRIUM ISOTHERM STUDIES OF METHYLENE BLUE FROM AQUEOUS SOLUTION UNTO ACTIVATED CARBON PREPARED FORM STRYCHNOS