From color to contaminant: Environmental impacts of textile dyes and emerging nanoparticle-based degradation strategies

The global textile industry is a dominant force in the worldwide consumption of freshwater resources, using over 100 billion liters each year, and represents nearly 20% of the total international trade volume of wastewater containing industrial dyes. The pollution caused by the industrial use of synthetic dyes such as azo, anthraquinone and reactive dyes, has a significant long-term impact on the environment. Contaminants caused by synthetic dyes affect the ecosystem by disrupting light penetration in water and increasing BOD/COD levels. They also produce toxic by-products of degradation at a slower rate, which are hazardous to health and biodiversity due to their mutagenic and carcinogenic properties. This review article intends to provide insight into the recent classifications of textile dyes and their associated environmental impacts, as well as the advances in nanoparticle photocatalytic degradation. The main focus of this review is the extensive use of photocatalysts in 2023–2025, in particular, the use of Ag–TiO₂, ZnO-, CuO-, semiconductor-based photocatalysts, and novel plant-derived, green-synthesized nanomaterials. Recent applications of advanced photocatalysts demonstrate that over 95% degradation of textile dyes occur with minimal light irradiation and optimal charge separation, plasmonic effects, and photocatalyst activation within the visible light range. This review explores contagion design, sustainable photocatalytic degradation, the recovery of catalysts and the environmental considerations associated with large-scale photocatalyst usage, as well as the challenges of realizing large-scale implementations.This review aims to enhance photocatalytic wastewater treatment technology to protect the environment, conserve water, and promote industrial sustainability. It does this by combining the most recent scientific breakthroughs with the practical aspects of green synthesis, catalyst stability, and wastewater treatment