A Comparative Study of the Adsorption of Lead in Aqueous Solution by Raw and Iron-Functionalized Bivalve Shell Powder

Water contamination by trace metals (TM), particularly lead (Pb²⁺), poses a major threat to human health and the environment. In Côte d’Ivoire, the growth of industrial and mining activities is exacerbating this pollution, creating a need for effective and accessible solutions. This study evaluated the effectiveness of raw bivalve shell powders (COQ) and iron-modified bivalve shell powders (COQ-Fe) for the removal of lead from aqueous solution. The lead in solution was analyzed by atomic absorption spectroscopy (AAS). The optimal conditions identified were: 1.5 g of powder per 100 mL, pH 5, and a contact time of 60 minutes. Under these conditions, COQ achieved 98.84% removal, and COQ-Fe achieved over 99% removal. Kinetic analysis showed a fit to the pseudo-second-order model, while the modified Langmuir model confirmed an ion exchange mechanism between Pb²⁺ and Ca²⁺. These results highlight the potential of bivalve shells as a local, sustainable, and low-cost solution for the remediation of water contaminated with heavy metals.