Investigation of lead removal from aqueous solutions using modified natural clay: Kinetics and thermodynamics approaches

Abstract

ABSTRACT. In this study, the natural clay was modified and removal of Pb²⁺ ions synthetically prepared aqueous solutions using this modified clay was investigated. The parameters affecting the adsorption efficiency were examined in the study. In the result of studies, the suitability of the adsorption data to classic adsorption models, and adsorption kinetics were determined. In the experiments, it has been determined that pH 5 provides optimum removal conditions of adsorption and adsorption reached equilibrium in approximately 15 min. The highest removal efficiency was found to be 82.13% with the addition of 3 g L^-1 adsorbent at a stirring speed of 200 rpm. As the lead concentration of the wastewater increases, the amount of lead retained per dry unit weight of the modified natural clay also increases. Experimental data showed that Pb²⁺ removal was consistent with Temkin adsorption model. Calculated thermodynamic constants showed that adsorption is exothermic and physical.

KEY WORDS: Adsorption, Isotherm, Lead removal, Natural clay, Thermodynamic constants

Bull. Chem. Soc. Ethiop. 2023, 37(1), 231-244.                                                                

DOI: https://dx.doi.org/10.4314/bcse.v37i1.18