Assessing The Efficacy Of Azadirachta Indica And Millettia Pinnata Leaf Powders As Low-Cost Biosorbents For Chromium (VI) Removal From Aqueous Solutions

Abstract

This study examines the efficiency of Azadirachta indica (Neem) and Millettia pinnata (Karanj) leaf powders as low-cost, eco-friendly adsorbents for removing hexavalent chromium from aqueous solutions. Batch adsorption experiments were conducted to evaluate the effect of adsorbent dosage (2–6 g/L) and initial Cr (VI) concentrations (50, 75, and 100 ppm) on removal efficiency and adsorption capacity. Results showed that removal efficiency increased with rising adsorbent doses and higher initial Cr (VI) concentrations for both biosorbents. Neem leaf powder consistently outperformed Karanj in Cr (VI) removal, achieving a maximum efficiency of 74.81% at 6 g/L for 100 ppm Cr (VI). Adsorption capacity (qₑ), however, declined with increasing adsorbent dosage due to site saturation and particle aggregation effects, with maximum values observed at the lowest dose (30.08 mg/g for Neem, 27.45 mg/g for Karanj). Overall, the findings highlight the potential of using Neem and Karanj leaf powders as sustainable adsorbents for the removal of Cr (VI) from contaminated water, with implications for scalable wastewater treatment technologies for heavy metal remediation.