Adsorption of chromium(VI) metal ions from aqueous solution using hexagonal ZnO particles: Equilibrium, kinetic and thermodynamic modelling studies

Abstract

Zinc oxide powders having hexagonal plate particles were prepared by homogeneous precipitation from boiling aqueous solutions that contained excess urea and 0.075 (Z075) and 0.300 (Z300) M Zn2+. The equilibrium, kinetic and thermodynamics of the adsorption of chromium (VI) from aqueous solution onto Z075 and Z300 were investigated. Thermodynamic parameters and K-# equilibrium constant of activation were calculated. Langmuir, Temkin and Dubinin-Radushkevich (D-R) isotherm models were used to describe the adsorption of Cr(VI) onto ZnO powders. The monomolecular adsorption capacity of Z075 and Z300 was determined as 980 and 1050mgg(-1) for Cr(VI), respectively.