Research on Adsorption of Pb2+ on to Microspheres Prepared by Rectorite and Humic Acid
Rectorite (REC), humic acid (HA) and polyvinyl alcohol (PVA) were used to prepare microspheres. Batch adsorption experiments of Pb2+ion on to the microspheres were performed. The results obtained indicate that adsorption time, the microspheres dosage and temperature were the main factors influencing the adsorptive capacities. The adsorption data for Pb2+ion were well described by the Freundlich, Langmuir and Temkin models. The kinetic experimental data properly correlated with the pseudo-first-order model, pseudo-second-order model and Elovich equation. The adsorption process is spontaneous, endothermic and out-of-order. The whole adsorption process is mainly controlled by entropies. The adsorption can be classified as chemical adsorption. The mechanisms for the adsorption of Pb2+ion on to the microspheres involved ion-exchange adsorption of Pb2+or the formation of complex compound. Under the experimental conditions employed, the removal of Pb2+ion attained value of 96.05%.