TiO₂ Nanoparticles for Textile Dyes-Laden Wastewater Treatment: Mechanisms, Reactive Oxygen Species, and Contemporary Challenges

The textile industry generates vast amounts of wastewater containing persistent and toxic dye compounds, posing severe environmental and health risks due to their resistance to conventional treatment methods. Titanium dioxide (TiO₂) nanoparticles have emerged as a promising solution, leveraging their photocatalytic properties to degrade complex dyes into harmless byproducts under light irradiation. These nanoparticles generate reactive oxygen species (ROS), such as hydroxyl radicals and superoxide anions, which break down dye molecules through oxidation processes. However, challenges like UV light dependency, electron-hole recombination, and nanoparticle recovery limit their practical application. Recent advancements focus on synthesizing TiO₂-based composites using methods like sol-gel, hydrothermal, and green synthesis, which enhance photocatalytic efficiency and stability. By integrating materials such as carbon, metals, or natural minerals, these composites improve dye adsorption, visible light absorption, and catalyst reusability. For instance, doping TiO₂ with metals like platinum or silver reduces recombination rates, while biochar-supported composites offer sustainable and cost-effective solutions. Despite these innovations, real-world implementation faces hurdles like interference from inorganic ions, pH sensitivity, and the economic viability of large-scale systems. Addressing these limitations requires optimizing synthesis techniques, developing hybrid materials, and designing systems that combine photocatalysis with other treatment processes. Future research must prioritize eco-friendly synthesis routes, long-term stability of composites, and scalable technologies to achieve efficient, affordable, and sustainable wastewater treatment. By overcoming these challenges, TiO₂-based nanomaterials hold significant potential to mitigate water pollution in the textile industry, aligning environmental and economic goals.