Recent innovations in nanocomposite beads for the removal of pollutants from water: a critical review

The escalating global water pollution crisis demands innovative and sustainable remediation strategies. This review critically assesses the application of nanocomposite beads as advanced adsorbents for efficiently removing diverse contaminants from aqueous environments. Nanocomposite beads, engineered with tailored physicochemical properties, offer significant advantages over conventional adsorbents due to their high specific surface area, tunable porosity, and adaptable surface functionalities. A comprehensive review summarises the nanocomposite bead-like layered double hydroxides (LDHs), metal–organic frameworks (MOFs), metal oxides, and carbonaceous materials. The review elucidates the structure–property relationships governing the adsorption performance of these nanocomposites. A detailed analysis of the underlying adsorption mechanisms is presented, encompassing physisorption (e.g., van der Waals interactions), chemisorption (e.g., covalent bonding, complexation), electrostatic interactions, ion exchange, and surface complexation. Furthermore, this review addresses the challenges of implementing nanocomposite beads in large-scale water treatment systems. Moreover, this study also provides a comprehensive roadmap for researchers working towards developing sustainable and cost-effective solutions for water purification using nanocomposite adsorbents.