Design Considerations of Photocatalysts for the Simultaneous Degradation of Mixed Pollutants in Wastewater: A Review

ABSTRACT

The growing presence of complex mixtures of pollutants in natural water bodies poses a major challenge to global water quality and environmental safety. Unlike single‐pollutant systems, real wastewater contains diverse organic, inorganic, microbial, and emerging contaminants that interact through competitive adsorption, synergistic effects, and inhibitory pathways, making their simultaneous removal highly demanding. Although many photocatalysts have been successfully demonstrated for degrading individual pollutants under isolated conditions, their simultaneous one‐pot degradation of coexisting pollutants remains relatively underexplored, largely due to the experimental and analytical complexity involved in evaluating photocatalytic efficiency in mixed systems. This gap is critical, as real‐world wastewater typically contains multiple pollutants concurrently, often exhibiting greater toxicity than individual contaminants. Photocatalysis has emerged as a promising advanced oxidation process capable of utilizing solar energy to treat such multifaceted pollutant matrices. This review provides a comprehensive overview of pollutant classes, photocatalytic mechanisms, photocatalyst design, and challenges associated with multi‐pollutant systems, including diverse organic‐organic, organic‐inorganic, and heavy‐metal mixtures. Furthermore, key experimental challenges, including spectral overlap and matrix interference that complicate accurate efficiency assessment, are highlighted. By integrating mechanistic insights, material innovations, and analytical limitations, this review outlines future directions for designing robust photocatalytic nanomaterials capable of treating realistic, complex wastewater streams.