Profile of parameters affecting adsorption of Hexavalent Chromium on low-cost adsorbent- The raw baggase

Abstract

The adsorption of Hexavalent chromium [Cr (VI)] from aqueous solution by raw baggase was studied as a function of initial pH, contact time, dose, concentration and temperature. The optimum initial pH for Cr (VI) uptake was 2.0. At the optimal conditions, Cr (VI) uptake was increased as the dose of adsorbent; the initial metal ion concentration and temperature were increased. Adsorption was fast initially and within the first 30 minutes of contact, the adsorption of Cr (VI) on baggase showed a total uptake of 84.4%. The adsorption data fitted well to Langmuir isotherm model. The maximum adsorption of baggase was found to be 9.4 mg/g. The kinetics of the adsorption was found to be pseudo-second-order. Thermodynamic parameters like activation energy, Gibbs free energy change, enthalpy and entropy were also evaluated. The values for activation energy and enthalpy were found to be 13.4 and 10.7 kJ/mol. Adsorption was found to be endothermic.