Sorption of iron, manganese, and copper from aqueous solution using orange peel: Optimization, isothermic, kinetic, and thermodynamic studies

Abstract

The adsorption of selected metals (Cu, Mn, and Fe) from water solution using orange peel was studied by means of batch mechanism. The aim of this study was to determine the dependency of the sorption process on pH of the solution, the initial concentration of the sorbent, contact time, and temperature. The Langmuier and Freundlich isothermal models were used to describe the sorption isotherms of ions. In this case the Langmuier model is more suitable to describe the data. The adsorption efficiency of removing copper (q(20) = 5 mg/g) and manganese (q(20) = 15 mg/g) by using orange peel was approximately 90%. Under optimal conditions, the efficiency of removing iron (q(20) = 10 mg/g) was approximately 55%. When studying the kinetics we discovered that the sorption process will follow the pseudo second-order. The thermodynamic parameters show an exothermic character of sorption, and the processes are spontaneous and favourable. The results indicate that it is possible to use orange peel effectively for removing selected metals from wastewater.