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DOI Prefix 10.20431 |
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International Journal of Advanced Research in Chemical Science
Volume-1 Issue-5, 2014, Page No:17-29
Evaluation of Kinetic and Thermodynamic Parameters of Chromium Adsorption on a Organobentonite
My.S.Slimani1,H.Ahlafi2,H.Moussout3,R.Chfaira4,O.Zegaoui5
Laboratory of Chemistry and Biology Applied to the Environment, Faculty of Sciences, My Ismail University, BP -Zitoune, Meknès, Morocco
Citation : My.S.Slimani,et.al, Evaluation of Kinetic and Thermodynamic Parameters of Chromium Adsorption on a Organobentonite International Journal of Advanced Research in Chemical Science. 2014;1(5):17-29.
Abstract
Bentonite (Bt) and the prepared hexadecyltrimethylammonium bromide bentonite (HDTMABt) were used to remove Cr(VI) from aqueous solutions. Characterization of these materials by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, GTA/DTA and surface area (BET) measurements demonstrated that the HDTMA+ polymer was intercalated in the interlayer space of Bt. The electrochemical studies revealed that the pH of point of zero charge (pHpzc) was close to pH = 10. Batch experiments indicated that the adsorption process proceeds kinetically according to pseudo-second-order model. The Langmuir and Freundlich adsorption isotherms provided the best correlation of the equilibrium data for both sample. HDTMA/Bt adsorbent showed a maximum efficiency, exhibiting a better adsorption capacity for Cr(VI) than Bt at pH = 2. Thermodynamic parameters including the Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°), were also calculated. These parameters indicated that adsorption of Cr (VI) onto HDTAM-bentonite was feasible, spontaneous and endothermic.
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