| Abstract |
| We synthesized Fe-coated vermiculite (Fe-CV) for the removal of Cr(VI) and investigated the mechanism of Cr(VI) adsorption onto Fe-CV. Fe-CV was synthesized at different Fe molar concentration to vermiculite ratio, i.e., 1, 2, 5, 8, 10 mol-Fe/kg. Fe-CV synthesized at 8 mol-Fe/kg was found to be most effective for the removal of Cr(VI) and further experiments were performed under batch condition using the Fe-CV. Kinetic sorption test and model analysis showed that observed data were well suited to pseudo second-order model, indicating that chemisorption dominates the process of Cr(VI) adsorption to Fe-CV. Equilibrium test demonstrated that Freundlich model well describes Cr(VI) adsorption to Fe-CV and the maximum Cr(VI) adsorption capacity of Fe-CV was 6.86 mg/g. Cr(VI) removal was the highest at pH 2 and decreased with increasing pH due to electrostatic repulsion between Cr(VI) and Fe-CV at higher pH. The effect of competing anions on Cr(VI) adsorption follows the order: PO43->Co32->So42->NO3-. The removal percentage of Cr(VI) was increased but the adsorbed amount of Cr(VI) per unit mass of Fe-CV was decreased as the increase of the dosage amount of Fe-CV. Finally, Fe-CV is an effective adsorbent for the removal of Cr(VI) and the results of this study are helpful for understanding the mechanism of Cr(VI) removal by Fe-CV. |
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| Key Words |
| Chromium, Fe-coated Vermiculite, pH, Anion Competition, Adsorption |
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