Preparation of TiO2-diatomite composites and photocatalytic degradation of dye wastewater

This study reveals the efficiency of Ti-hyflo, Ti-C535, and Ti-C560 diatomite-TiO2 composites prepared using the sol-gel method in degrading dye under UVc irradiation. Photocatalytic degradation of Rhodamine B dye solution (10 mg/L) was examined at pH 3 using varying lamp powers (6 W and 18 W) and TiO2-diatomite dosages (0.1 g/L, 0.2 g/L, and 0.4 g/L). The experiment included color removal analysis of a dilute dye bath of a textile industry. Photocatalytic degradation experiment results reveal a similar performance for Ti-C535 and Ti-C560 composites, which was much higher compared to that of Ti-hyflo, indicating a maximum RhB removal of 99.9%, 99.8%, and 82%, respectively, and a decrease in UV absorbance value from 2.93 to 0.15 under 18 W lamp power. The case of low lamp power (6 W) resulted in a longer reaction time, with a similar best performance (95%) recorded at 0.2 g/L dosage in 4 h using Ti-C535. The excellent performance of Ti-C560 and Ti-C535 composites is attributed to the formation of interfaces between diatomites and TiO2 nanoparticles which improves the photocatalytic activity. When the dosage was increased to 0.4 g/L, the RhB degradation efficiency diminished for all composites, decreasing to a minimum of 72%. The RhB degradation kinetic curves satisfied a pseudo-first-order kinetic model. After 4 repeated use, the composite still revealed strong photocatalytic activity, suggesting that it might be useful in wastewater color removal applications. The dye bath degradation experiment showed the color removal potential in textile wastewater, with removal rates of 63% and 90% at 525 nm and 625 nm wavelengths, respectively.

Automated summary

This study examines the efficiency of Ti-hyflo, Ti-C535, and Ti-C560 diatomite-TiO2 composites prepared by the sol-gel method in degrading dye under UVc irradiation. The photocatalytic degradation experiment results reveal that Ti-C535 and Ti-C560 composites have similar performance, much higher than that of Ti-hyflo. The excellent performance of Ti-C560 and Ti-C535 composites is attributed to the formation of interfaces between diatomites and TiO2 nanoparticles, improving the photocatalytic activity.