Entrapment behaviours of trivalent and hexavalent chromium from aqueous medium using edible alkali-derived activated carbon of Eichhornia crassipes (water hyacinth).

Abstract

The study examines the adsorption capabilities of an environmentally friendly activated carbon derived from a novel activating agent, i.e., an edible alkali prepared from black gram plant ash, for the removal of Cr(III) and Cr(VI) ions from an aqueous environment. The results of the systematic research show impressive removal efficiencies of 95.12% for Cr(III) ions and 99.6% for Cr(VI) ions. The kinetics and equilibrium data of the adsorption process confirm to the pseudo-second-order kinetics and Freundlich isotherm model. The thermodynamic analysis reveals the adsorption process as feasible and spontaneous across the temperature range of 298-313K. The mechanism entails electrostatic attraction and adsorption of Cr(III) and Cr(VI) ions on oppositely charged surfaces and the participation of oxygen-containing functional groups on WHAC-BGA surface in the reduction of Cr(VI) to Cr(III). This study provides valuable insights for optimizing strategies to combat chromium contamination in water sources, offering a sustainable solution with the potential for real-world application.