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International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
ISSN: 1735-1472
EISSN: 1735-2630
Vol. 9, No. 2, 2012, pp. 319-326
Bioline Code: st12032
Full paper language: English
Document type: Research Article
Document available free of charge

International Journal of Environment Science and Technology, Vol. 9, No. 2, 2012, pp. 319-326

 en Hexavalent chromium removal from aqueous solutions by using low-cost biological wastes: equilibrium and kinetic studies
Aliabad, M.; Khazaei, L.; Fakhraee, H. & Mousavian, M. T. H.

Abstract

The batch removal of hexavalent chromium from aqueous solutions using almond shell, activated sawdust, and activated carbon, which are low-cost biological wastes under different experimental conditions, was investigated in this study. The influences of initial concentration, adsorbent dose, adsorbent particle size, agitation speed, temperature, contact time, and pH of solution were investigated. The adsorption was solution pH dependent and the maximum adsorption was observed at a solution pH of 2.0. The capacity of chromium adsorption under equilibrium conditions increased with the decrease in particle sizes. The equilibrium was achieved for chromium ion after 30 min. Experimental results showed that low-cost biosorbents are effective for the removal of pollutants from aqueous solution. The pseudo-second-order kinetic model gave a better fit of the experimental data as compared to the pseudo-first-order kinetic model. Experimental data showed a good fit with the Freundlich isotherm model. Changes in the thermodynamic parameters, including Gibbs free energy (ΔGo), enthalpy (ΔHo), and entropy (ΔSo), indicated that the biosorption of hexavalent chromium onto almond shell, activated sawdust, and activated carbon was feasible, spontaneous, and endothermic in the temperature range 28–50 ° C.

Keywords
Activated sawdust; Almond shell; Biosorption; Endothermic; Modeling

 
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