International Journal of Environmental Sciences

In the present study, Shorea Robusta leaf litter, a nonconvectional material, is proposed as a novel material for preparation of carbonaceous adsorbent impregnated with phosphoric acid, used for the reduction of Zinc and Copper metal ions from aqueous phase. For batch process, operating variables studied were adsorbent dose, contact time, initial metal ion concentration, pH and temperature. Sorption experiments indicated that the sorption capacity was dependent on operating variables and the process was strongly pHdependent. Kinetic measurements showed that the process was uniform and rapid. In order to investigate the mechanism of sorption, kinetic data were modeled using the pseudofirstorder and pseudosecondorder kinetic equations, and intraparticle diffusion model. Among the kinetic models studied, the pseudosecondorder equation was the best applicable model to describe the sorption process. Equilibrium isotherm data were analyzed using the Langmuir, Freundlich and Temkin isotherms. The Langmuir model yields a much better fit than the Freundlich and Temkin models. Isotherms have also been used to obtain the thermodynamic parameters such as free energy, enthalpy, and entropy of sorption. The value of ΔH^° is negative, indicating that the Zinc and Copper adsorption by the simulated activated carbon are exothermic in nature.