Development of low cost bio sorbent for the treatment wastewater containing toxic metals

Agricultural byproducts such as rice husk, black gram husk, wheat bran, pea pod and cotton and mustard seed cakes were evaluated as a bio sorbent for the removal of cadmium from contaminated water. All these byproducts, except rice husk and pea pod, exhibited an excellent bio sorption potential for Cd. Black gram husk (bgh) was found to have the highest sorption capacity with approx. 100% removal of Cd from contaminated water. Studies indicated that sorption of Cd increased with increase in pH and reached a plateau at pH 5.0. The rate of Cd uptake was maximum in first 10 min and the equilibrium of the system was achieved after 30 min. Presence of interfering cations such as Na, K, Mg and Ca did not affect Cd sorption significantly. Breakthrough curves of fixed bed column bioreactor filled with pgh were optioned to illustrate the process of Cd removal in continuous flow system. Desorption of Cd laden column bioreactor with 0.1 M HCl indicates the reuse possibility of this newly developed bgh bio sorption system. (author)