Abstract
The environmental persistence of thiamethoxam (THX), a commonly used neonicotinoid insecticide, raises concerns about its long-term effects. This study explored the photocatalytic degradation of THX using pure and perlite supported TiO<sub>2</sub> photocatalysts in two distinct UV photoreactor configurations. Our investigation aimed to identify some optimal conditions for efficient THX removal while considering cost-effectiveness and sustainability for potential industrial applications. The results revealed that horizontal UV irradiation (System 1) significantly surpassed vertical irradiation (System 2) in both THX degradation rate and energy efficiency. This highlights the importance of photoreactor design for maximizing light utilization and mass transfer. While pure TiO<sub>2</sub> exhibited superior performance in both systems compared to perlite-supported TiO<sub>2</sub> (PST), the latter demonstrated an intriguing temperature dependence. PST achieved enhanced degradation at higher temperatures, suggesting its potential for industrial applications where waste heat is available. Furthermore, we discovered that low pH conditions substantially boosted THX degradation with PST, opening a promising avenue for optimizing industrial processes and minimizing chemical usage. This finding underscores the crucial role of operational parameters in tailoring photocatalytic performance. In conclusion, this study provided strong evidence for the effectiveness of TiO<sub>2</sub> photocatalysis in degrading THX, a persistent organic pollutant. We emphasized the impact of catalyst support, photoreactor design, and operational parameters, such as temperature and pH, on treatment efficiency. Notably, the enhanced performance of PST at higher temperatures and its responsiveness to low pH conditions suggest its potential for cost-effective and sustainable THX treatment in industrial settings. These findings pave the way for further research and development of optimized photocatalytic systems for mitigating environmental contamination by THX and other persistent organic pollutants.