Okra Leaves—Agricultural Waste for the Removal of Cr(III) and Cr(VI) from Contaminated Water

The present study demonstrates the sorptive efficiency of okra leaves for the Cr(III) and Cr(VI) in aqueous system. The batch dynamic sorption method was carried out as the function of the pH of the solution, sorbent doze, initial bulk concentration, shaking speed and contact time. The experimental data were examined by Langmuir and Freundlich isotherms. Cr(III) at pH-4.0 and Cr(VI) pH-2.0 showed a maximum sorption capacities 221.17 mg/g and 81.94 mg/g respectively. Kinetically experimental data of both chromium species were well fitted to pseudo second order rate, Elovich, Morris-Weber and Richenberg equations. Positive values of enthalpy change and negative values of Gibbs free energy indicated the endothermic and spontaneous nature of sorption reaction respectively. The developed method was applied to real ground water samples (affected by industrial wastewater). Up to 92.15% of chromium metal was removed from the real water samples.