Recent Advancements in Photocatalytic Nanomaterials for Wastewater Remediation

The increasing discharge of industrial and municipal wastewater containing persistent organic pollutants, dyes, pharmaceuticals, pesticides, and heavy metals has become a major environmental concern. Conventional wastewater treatment processes are often limited by high operating costs, incomplete pollutant removal, and the formation of secondary contaminants. Photocatalytic treatment based on nanostructured semiconductor materials has emerged as a promising advanced oxidation technology because of its ability to utilize light energy to generate highly reactive species capable of degrading a wide range of recalcitrant pollutants. This review presents recent advancements in photocatalytic nanomaterials for wastewater remediation, with particular emphasis on titanium dioxide (TiO₂), zinc oxide (ZnO), graphitic carbon nitride (g-C₃N₄), heterojunction photocatalysts, doped nanomaterials, and carbon-based nanocomposites. The fundamental mechanisms of heterogeneous photocatalysis and the roles of photogenerated electrons, holes, hydroxyl radicals, and superoxide radicals are discussed. Recent strategies for improving photocatalytic efficiency, including elemental doping, morphology engineering, defect construction, heterojunction formation, surface modification, and catalyst immobilization, are also reviewed. In addition, the application of photocatalytic nanomaterials for the removal of dyes, pharmaceutical residues, antibiotics, organic contaminants, and heavy metals is examined. Despite considerable progress at laboratory scale, challenges related to catalyst recovery, long-term stability, visible-light utilization, energy consumption, real wastewater complexity, and large-scale reactor design remain. Future research should therefore focus on stable, recyclable, solar-driven, and environmentally safe photocatalysts with improved performance under realistic wastewater conditions.

کلیدواژه ها:

Photocatalysis ، Nanomaterials ، Wastewater remediation ، TiO₂ ، ZnO ، g-C₃N₄ ، Heterojunction ، Advanced oxidation processes