Kinetic modeling of Cu2+, Cd2+ and Pb2+ ions adsorption onto raw and modified Artocarpus heterophyllus L. seeds from a model solution

Abstract

Heavy metals contaminated water has detrimental health effects to human beings and animals not limited to hypertension, kidney damage, cancer and eventual death. Available water treatment methods have proved to not only function at high operation costs and ineffective but also yielded insignificant results to a local ordinary Kenyan citizens. The present study investigates the use of Jackfruit seeds wastes as a low cost adsorbent in adsorption water treatment technique. Raw and modified Jackfruit seeds adsorbent were applied to study kinetic studies of Cu2+, Cd2+ and Pb2+ ions adsorption from an aqueous solution under batch conditions. The adsorption behavior of the three metal ions onto raw and modified adsorbents was monitored spectrophotometrically and analysed with Pseudo-first-order and Pseudo-second-order kinetic models. Correlation coefficients (R2) confirmed that all experimental data fitted Pseudo-second-order with R2 > 0.984 which implied a chemisorption process. Experimental and calculated adsorption capacities was higher for modified adsorbent with Pb2+ ions registering higher values. The rate constants (k2) was higher in modified adsorbent than in raw adsorbent with Pb2+ ions registering highest value of rate of 4.54×10-1 (mg g-1min-1). Adsorption capacities was in the order of Pb2+ > Cu2+ > Cd2+. The results showed viability of the adsorbents for the removal of the heavy metals from waste solution in an economical and environmental friendly manner.