Spent kaolin filter cake as an effective adsorbent for the removal of Hexavalent Chromium [Cr (VI)] from aqueous solution: Comparative study of wastewater treatment methods

Abstract

In this research three types of filter cake kaolin adsorbents were prepared using different method to remove hexavalent chromium Cr (VI) from aqueous solution. The surface functional groups, surface morphology and crystallinity of adsorbents were characterized using FTIR, SEM and XRD, respectively. The major and minor oxide compositional analysis confirmed a high SiO2 / Al2O3 for Beneficiated sample. The effects of operating factors like pH, initial concentration, adsorbent dosage, contact time and temperature have been investigated on batch adsorption experiment. The maximum removal efficiencies were 84.39, 77.32 and 71. 44 onto Beneficiated, Raw and calcined filter cake adsorbents, respectively. The adsorption process was further investigated using Langmuir and Freundlich isotherm models in which the equilibrium data obeyed Langmuir isotherm model. Thermodynamic parameters such as standard free Gibbs energy change (ΔGo), standard enthalpy changes (ΔHo) and standard entropy change (ΔSo) were calculated. Adsorption kinetics models resulted data fitted to the pseudo-first order model.