A Review on Green Hydroxyapatite Nanoparticles and Composites for Sustainable Pollutant Removal

Rapid industrialization has significantly contaminated aquatic ecosystems with heavy metals, dyes, and pharmaceutical pollutants, threatening ecosystems and human health. Hydroxyapatite (HA) synthesized from natural sources has emerged as an eco-friendly remediation material due to its exceptional adsorption capacity, ion-exchange capability, and cost-effectiveness. Despite extensive studies on HA synthesis, the relationship between green-synthesis strategies and pollutant-removal efficiency remains underexplored. This review summarizes recent advances in green-synthesized HA nanoparticles and composites, correlating synthesis conditions and functionalization strategies with material properties and pollutant-removal efficiencies, underlying adsorption–photocatalysis synergy. The findings indicate green-HA materials enable efficient, versatile pollutant removal for sustainable water remediation.