Adsorptive Removal of Hexavalent Chromium from Aqueous Solution Using Activated Carbon Derived from Agricultural Waste

Abstract

The contamination of water by hexavalent chromium, a toxic and carcinogenic heavy metal discharged by several industries, poses a serious environmental and health hazard, and its removal by inexpensive adsorbents is an attractive treatment route. This paper reports the adsorptive removal of hexavalent chromium from aqueous solution using activated carbon prepared from an agricultural waste. The adsorbent was prepared by chemical activation and used to treat synthetic chromium solutions, and the effects of contact time and adsorbent dose on the removal were studied, with the equilibrium data analysed by the Langmuir and Freundlich isotherm models. The results show that the removal of chromium increased with contact time until equilibrium and with the adsorbent dose, that a high removal was achieved under favourable conditions, and that the equilibrium data were described better by the Langmuir model, indicating monolayer adsorption, with a substantialmaximum adsorption capacity. The study demonstrates that activated carbon derived from agricultural waste is an effective and low-cost adsorbent for the removal of hexavalent chromium from water.  KEYWORDS: Adsorption, Hexavalent Chromium, Activated Carbon,Agricultural Waste, Water Treatment, Adsorption Isotherm, Heavy MetalRemoval