Chitosan functionalized nanocomposites for adsorption of hexavalent chromium from contaminated water and evaluation of adsorption mechanisms

Hexavalent chromium (Cr (VI)), one of the most toxic heavy metal ions in aquatic systems, primarily originates from industrial activities like electroplating, leather tanning and pigment production. Its superior solubility, strong oxidizing power, and membrane permeability make Cr (VI) considerably more toxic and carcinogenic than trivalent chromium (Cr (III)). Due to these profound risks to human and animal health, effective removal of Cr (VI) from polluted water is critical. Although numerous physicochemical and biological techniques have been investigated, adsorption stands out for its straightforwardness, high performance, and economic viability. Chitosan-coated nanocomposites, with their expansive surface areas and plentiful active sites, show great promise as adsorbents for Cr (VI) uptake. Chitosan derived from chitin; this linear biopolymer introduces abundant functional groups that boost reactive sites on the nanocomposite surface. The Cr (VI) adsorption process on these materials can be analyzed through isotherm, kinetic, and thermodynamic models. This review discusses recent advances in synthesizing and deploying chitosan-modified nanocomposites for Cr (VI) remediation in wastewater, underscoring their value in eco-friendly water purification.