F. U. Okwunodulu, F. K. Onwu and S. A. Odoemelam
Conventional remediation techniques for toxic heavy metals from polluted water are expensive and are equally not environmentally friendly. In this research, both unmodified and mercaptoacetic acid modified oil bean seed shells as bioremediators were tested for their abilities to adsorb Cd2+, Ni2+ and Pb2+ from their aqueous solutions. Experimental parameters like pH of the solution and temperature were investigated using a batch adsorption technique to explore their variation effect on treating polluted water of trace elements. Results showed that the adsorption of these metal ions were pH dependent. Optimum removal of Cd2+ occurred at pH 8 with removal efficiency of 99.99 % while Ni2+ and Pb2+ had their maximum removals at pH 6 and 10 respectively and both having removal efficiency 99.99 % by the unmodified biosorbent. For the modified oil been seed shell, maximum removal for Cd2+ was at pH 8 with percentage removal of 99.989 % while those of Ni2+ and Pb2+ occurred at pH 10 with removal efficiencies of 98.89 and 99.42 % respectively. Generally, high metal uptake was achieved at low temperature for both unmodified and modified oil bean seed shell. The data correlated well with Arrhenius model with R2 values ranged from 0.7 – 0.9. ΔG0, ΔH0 and ΔS0 values obtained showed that the adsorption process was spontaneous, endothermic and occurred with increasing degree of orderliness.
