Cd(II) Adsorption from Aqueous Solution Onto Cucumis sativus Peel:Equilibrium, Thermodynamic and Kinetic Study

Abstract

This paper reports the feasibility of using Cucumis sativus peel (CSP) for cadmium sorption from aqueous solution under different experimental conditions. Effect of various process parameters, viz. pH, adsorbent dose, contact time, initial concentration and temperature has been studied for the removal of cadmium. The applicability of different kinetic and isotherm models for the adsorption process was also evaluated. The isotherm modelling data fitted best to Freundlich model having regression coefficient (R2=0.999) showing monolayer adsorption on heterogenous surface. The governing kinetic mechanism in sorption process was pseudo second order model. Thermodynamic parameters revealed the feasibility, spontaneity and exothermic nature of adsorption. FTIR and SEM of CSP (before and after exhaustion) were recorded to explore number and position of the functional groups available for the binding of Cd(II) ions and surface morphology of adsorbent. Data reveal the involvement of functional group for binding the Cd(II) on the surface of adsorbent. In comparison to other adsorbents, the sorption capacity of the CSP for cadmiumcontaminated effluents may prove to be economical and feasible.