BIOREMEDIATION OF CHROMIUM VI USING MANGO LEAVES (MANGIFERA INDICA) AS ADSORBENT

ABSTRACT Hexavalent chromium (Cr(VI)) contamination from industrial effluents poses severe environmental and health risks due to its high toxicity, carcinogenicity, and mobility in aqueous systems. This study investigated the bioremediation potential of mango leaves (Mangifera indica) powder as a low-cost, eco-friendly biosorbent for removing Cr(VI) from contaminated water. Mature mango leaves were collected, sun-dried, pulverized, and sieved to 250μm particle size to enhance surface area for adsorption. Batch adsorption experiments were conducted to evaluate the effects of adsorbent dosage (0.1-1.2g), contact time (5-90 minutes), initial Cr(VI) concentration (5-25 mg/L), pH (4, 7, 9), and temperature (20-50°C) on removal efficiency. Results demonstrated that optimal Cr(VI) removal of 86% was achieved at pH 2 with 1.2g adsorbent dosage within 90 minutes contact time. The adsorption efficiency decreased with increasing adsorbent dosage beyond optimal levels, likely due to particle aggregation and reduced effective surface area. Higher initial Cr(VI) concentrations (5-25 mg/L) maintained removal efficiencies between 71-86%, indicating robust adsorption capacity. The study confirms that mango leaves powder possesses functional groups capable of effectively binding and reducing Cr(VI) to less toxic Cr(III) through biosorption mechanisms including ion exchange, complexation, and electrostatic interactions. This research contributes to sustainable environmental management by demonstrating that abundant agricultural waste can serve as an effective biosorbent for heavy metal remediation, offering a cost-effective alternative to conventional physicochemical treatment methods while promoting circular economy principles in addressing industrial wastewater pollution challenges.