UV photodegradation of textile dyes using TiO₂–ZnO supported on banana peel activated carbon

In this work, the UV-photodegradation efficiency of a novel TiO₂–ZnO/ Banana activated carbon photocatalyst composite monitored by colour and chemical oxygen demand reduction of rhodamine 6 G dyes in a 6 W-UV photoreactor system was investigated. A TiO₂–ZnO Banana activated carbon photocatalyst composite was synthesized by immobilizing ZnO on TiO₂ and subsequently supporting the TiO₂–ZnO hybrid on banana peel activated carbon. X-ray diffraction patterns and Fourier transform infrared revealed the successful TiO₂–ZnO hybridization and the introduction of Banana activated carbon. Photoluminescence spectroscopy and solid-state electronic absorption spectra confirmed restrained electron–hole recombination and reduced bandgap energy attributed to Banana activated carbon as an electron acceptor and heterojunction formation, respectively, which enhanced photocatalytic activity. Photocatalytic results showed that TiO₂–ZnO Banana activated carbon (51:9:40) showed a higher colour removal of 96% compared to 46%, 31%, and 56%, respectively, for TiO₂, ZnO and TiO₂–ZnO (85:15) after 160 min of irradiation time. The study also revealed that UV-photodegradation is more effective in colour removal of the rhodamine 6 G dye with about 96% as compared to 79% Chemical Oxygen Demand reduction. The colour removal of rhodamine 6 G dye was still as high as 90% after four runs, confirming the good stability and reusability of the TiO₂–ZnO Banana activated carbon composite. The optimum pH and temperature for photodegradation were found to be 8 and 40 ℃, respectively. Through modification, TiO₂–ZnO/Banana activated carbon composite was found to be an economical and environmental feasible photocatalyst.