Application of photocatalytic hydrogels used for the degradation of dyes, pharmaceuticals and other contaminants in water

Various types of pollutants, including dyes, pharmaceuticals, heavy metals, and other contaminants, pose significant risks for aquatic species and humans. Photocatalytic hydrogels (PCHs), which synergistically combine adsorption and photocatalysis, offer a promising solution by combining the adsorption and photodegradation of these contaminants under UV or visible light. Photocatalysts such as TiO₂, ZnO, Ag, Bi, and non-metallic catalysts can be incorporated into diverse hydrogel matrices, providing flexibility for designing PCHs tailored to specific applications. This review explores the synthesis, properties, and performance of various PCHs, with a focus on their ability to adsorb and/or degrade contaminants such as dyes (e.g., methylene blue, methyl orange, rhodamine B), pharmaceuticals (e.g., tetracycline, ciprofloxacin, 17 estradiol), biological contaminants (e.g., algal blooms), and heavy metals (e.g., Cr (VI)). Additionally, the recyclability of PCHs is addressed. PCHs represent a versatile and eco-friendly approach to advancing water remediation technologies.