Photocatalytic Degradation of Caffeine in Water using Titanium Dioxide-Coated Materials

Caffeine is a widely used stimulant, is increasingly detected in aquatic environments due to its persistence and incomplete removal by conventional wastewater treatment processes. Its presence poses ecological risks, including adverse effects on aquatic life at concentrations as low as 0.91 mg/L. To address this issue, this study investigates the photocatalytic degradation of caffeine using titanium dioxide (TiO₂)-coated materials—specifically glass beads, alumina balls, and ceramic balls—prepared via the sol-gel method. The materials were characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) to evaluate surface morphology and TiO₂ distribution. Photocatalytic experiments were conducted using synthetic wastewater with a caffeine concentration of 3.6 mg/L under three conditions: dark (adsorption), UV-C light without catalyst (photolysis), and UV-C light with TiO₂-coated materials (photocatalysis). Caffeine degradation was monitored using high-performance liquid chromatography (HPLC). Results showed that surface texture played a key role in TiO₂ adhesion and photocatalytic efficiency. Ceramic balls, having the roughest surface, exhibited the highest TiO₂ adherence and achieved a degradation efficiency of 99.47% after 360 minutes of UV-C exposure. Glass beads and alumina balls achieved 90.19% and 67.37% degradation, respectively. The superior performance of ceramic balls is attributed to their enhanced surface area, promoting stronger TiO₂ bonding and more active sites for photocatalytic reactions. This study demonstrates the effectiveness of TiO₂-coated ceramic balls in reducing caffeine concentrations in wastewater to environmentally safe levels. The findings offer a promising and cost-effective approach for integrating photocatalytic materials into advanced wastewater treatment systems. Further research is recommended to explore scalability and real-world application in industrial settings.