Optimization of adsorption of Cr(VI) from aqueous solution by adsorbent prepared from Leucaena leucocephala seed shell using design of experiment

The activated carbon was prepared from Leucaena leucocephala seed shell and used as adsorbent for the removal of hexavalent chromium [Cr(VI)] from aqueous solution. The variables affecting the adsorption process were optimized using response surface methodology (RSM). ANOVA revealed that all the variables studied had significant effects on the process. The obtained data showed that 71.49 mg/L initial Cr(VI) concentration, 4.22 solution pH, 0.57 g adsorbent dosage and 26.2 degrees C temperature resulted in 95.62% adsorption. Equilibrium adsorption isotherm and kinetic studies showed that Freundlich isotherm and the pseudo-second-order kinetic model fitted well to the experimental data.