Design of Spinel Nanomaterials for Photocatalytic Degradation of Water Contaminants

Abstract

Water contamination caused by industrialization, urbanization, and agricultural activities has emerged as a major global environmental challenge. The presence of persistent organic pollutants, dyes, pharmaceuticals, pesticides, and heavy metals in aquatic systems poses serious risks to both human health and ecosystems. Among various wastewater treatment technologies, photocatalysis has gained significant attention as an environmentally friendly and sustainable approach for the degradation and mineralization of water contaminants. In recent years, spinel nanomaterials with the general formula MFe2O4 (M = Co, Ni, Zn, Mn, Mg, Cu, etc.) have emerged as promising photocatalysts owing to their unique structural, optical, magnetic, and electronic properties. Their narrow band gaps, high chemical stability, facile magnetic recovery and tunable surface characteristics make them suitable candidates for visible-light-driven photocatalytic applications. This review provides a comprehensive overview of the design strategies employed to enhance the photocatalytic performance of spinel nanomaterials for water purification. Particular emphasis is placed on the degradation mechanisms of various water contaminants, including organic dyes, pharmaceutical residues, pesticides, and emerging pollutants under UV and visible-light irradiation. This review aims to provide valuable insights into the rational design of next-generation spinel photocatalysts for effective remediation of water contaminants.