Comparative Analysis of Coconut Shell and Iron-Impregnated Activated Carbon for Heavy Metal Removal from Aqueous Solutions

The increasing presence of heavy metal contaminants such as lead (Pb²�), cadmium (Cd²�), and arsenic (As³�) in water sources has raised significant environmental and health concerns. These elements are toxic, non-biodegradable and tend to accumulate in the tissues of living organisms that causes various disorders. This review examines and compares the adsorption efficiency of two promising adsorbents—coconut shell powder and iron-impregnated activated carbon (Fe-AC)—for heavy metal removal from aqueous solutions. Both materials demonstrate adsorption potential, following the pseudo-second-order kinetic model and Freundlich isotherm, suggesting a heterogeneous adsorption process. Coconut shell, a low-cost and eco-friendly biosorbent, exhibits effective removal capacity, particularly for Pb²�, with adsorption influenced by pH (optimal at 8-10), temperature, and initial metal concentration. However, Fe-AC offers higher adsorption efficiency, faster kinetics, and reduced adsorbent dosage requirements, particularly excelling in the removal of As³� and Cd²�. The incorporation of iron enhances surface reactivity, leading to greater adsorption at a lower contact time (90-120 min for Fe-AC vs. 180 min for coconut shell). This review highlights the trade-offs between cost, efficiency, and sustainability when selecting adsorbents for wastewater treatment. While Fe-AC provides superior metal removal performance, higher adsorption rates and lower adsorbent dosage whereas coconut shell remains an accessible, natural alternative suitable for large-scale applications. requirements, coconut shell remains a low-cost, sustainable, and eco-friendly alternative suitable for large-scale applications. This study highlights the potential of both materials as viable adsorbents for wastewater treatment, with Fe-AC excelling in efficiency and coconut shell offering an accessible and natural remediation solution.