Rice husk and maize stem powder: Powerful adsorptive remover of chromium

Chromium is released into water bodies through metallurgical operations, metal finishing, steel alloy and chrome plating. Various techniques for removal of hexavalent chromium from aqueous medium such as ion exchange, coagulation, membrane filtration, electro dialysis are available. The mutagenic and carcinogenic properties of hexavalent Chromium required the need of remedial measures using rice husk and maize stem powder to avoid high cost involved in traditional methods. Agriculture bye products and wastes have been exploited for remediation of Cr (VI) in order to know the feasibility of biosorption. Carboxylic acid group, hydroxyl group, lignin and carbohydrate present in rice husk and maize stem increase the adsorption potential for Cr (VI). 2 ppm initial concentration of Cr (VI) is treated with 1 gm rice husk up to 1 hour, 2 hours and 3 hours and 2 gm and 3 gm rice husk up to 1 hour decreased the concentration up to a minimum of 0.13 ppm while in case of maize stem powder the equilibrium concentration was 0.247 ppm at pH 7.00. A Langmuir adsorption isotherm has been tested from available data. Adsorptive removal of Cr (VI) follows first order kinetics.