Cerium and samarium doped TiO₂ for degradation of crystal violet dye in wastewater by photo-degradation method

Crystal Violet is a toxic dye commonly found in wastewater from textile and printing industries. It is harmful to both the environment and human health due to its non-biodegradable and carcinogenic nature. Removing such dyes from water is a major challenge. In this study, we used a process called photocatalysis, where light energy helps to break down harmful chemicals, to degrade Crystal Violet dye. Titanium dioxide (TiO₂), a well-known photocatalyst, was used as the base material. To improve its efficiency, we added small amounts of two rare earth elements Cerium (Ce) and Samarium (Sm) to the TiO₂ structure. The doped TiO₂ photocatalysts were prepared using the co-precipitation method, which allows for even distribution of the dopant metals in the material. After synthesis, the materials were analyzed using different techniques to understand their crystal structure, surface properties, light absorption, and electron movement during the reaction. Photocatalytic activity was tested under UV light to evaluate how effectively the materials could degrade Crystal Violet. We studied the effects of various factors such as catalyst amount, dye concentration, solution pH, and light exposure time. The results showed that both Ce- and Sm-doped TiO₂ performed significantly better than undoped TiO₂. Over 90% of the dye was removed in a short time, with samarium-doped TiO₂ showing slightly better results than cerium-doped TiO₂ due to better electron trapping and redox properties. This study suggests that doping TiO₂ with rare earth metals is a promising and eco-friendly method for treating dye-contaminated wastewater.