F. U. Okwunodulu, S. A. Odoemelam
Abstract: Exploitation of unmodified and thioglycolic acid modified waste as a low-cost adsorbent for the adsorption of Cd2+Ni2+ and Pb2+ from simulated aqueous solutions was investigated. The results clearly demonstrate the effect of particle size and contact time as important experimental parameters on the adsorption process in batch experiments. The maximum evaluated particle size concentration and time concentration for Cd2+, Ni2+ and Pb2+ uptake onto unmodified and modified Telfairia occidentalis waste biomass were 99.68 mg/g Cd2+, 99.99 mg/g Ni2+, 99.75 mg/g Pb2+at 250 m for the unmodified and 98.78 mg/g Cd2+, 98.88 mg/g Ni2+ at 250m and 98.52 mg/g Pb2+ at 125 m for the modified waste. 99.99 Cd2+, 99.99 mg/g Ni2+ and 99.89 mg/g Pb2+ at 10 minutes for the unmodified waste and 99.45 mg/g Cd2+ at 60 minutes, 99.73 mg/g Ni2+ at 90 minutes, 88.80 mg/g Cd2+at 90 minutes for the modified. The kinetic of metal ions adsorption on Telfairia occidentials waste biomass has also been studied by fitting the data in Lagergrens first-order, Ho-Mckays pseudo-second-order kinetics hypothesis and Elovich adsorption model. It was observed that the removal of metal ions over the waste biomass showed a better fit with the pseudo-second-order process and Elovich adsorption model than the pseudo -first-order.
Keywords: Adsorption kinetics, contact time, heavy metal ions, particle size, Telfairia occidentalis coat