Author: Nihal BEKTAŞ, Salim öNCEL
Publishing Date: 2004
Volume 19 Issue 1
Lead is one of toxic pollutant, which causes severe environmental problems. The main industrial sources for lead include metal finishing, mining and mineral processes, and oil refining industries. Lead can accumulate along the food chain and is not amenable to biological degradation. Therefore wastewater, containing lead needs to be treated before discharging to the receiving medium. Sepiolite deposits, also known as lületaşı, are widely distributed around Eskişehir. The most important use of sepiolite is to manufacture of jewellery, tobacco-pipe, vase etc.. These manufacturers produce large amount of waste sepiolite in the form of crumb and powder, which can be used as adsorbent in the wastewater technology. The aim of this work is to evaluate the removal of lead from aqueous solution using waste sepiolite. The sorption kinetics were tested for the pseudo-first order, pseudo-second order reaction and Elovich equation at different experimental conditions. The rate constants of sorption for all these kinetic models were calculated. Good correlation coefficients were obtained for the pseudo second-order kinetic model showing that lead uptake process followed the pseudo-second order rate expression. Langmuir and Freundlich isotherm constants and correlation coefficients for the present system were calculated and compared. The equilibrium process was described well by the Langmuir isotherm model with the maximum sorption capacity of 22.5 mg/g of lead on sepiolite.
Key Words: Lead removal; sepiolite; kinetic models; isotherm models.