Photocatalytic dye degradation from textile industry wastewater

In this study, Cs-TPA/TiO₂ catalysts containing different loading percentages of Cs-TPA were synthesized. The catalysts with varying loading ratios of %xCs-TPA/TiO₂ (x = 1%, 2.5%, 5%, 7.5%, and 10%) were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), UV-DRS and BET analyses, and the results were interpreted. The photocatalytic activities of %xCs-TPA/TiO₂ catalysts with different loading percentages were investigated under UV light using a synthetic dye solution prepared with the mono-azo dye C.I. Reactive Black 5. For the color removal of C.I. Reactive Black 5, catalysts with different loading ratios of %xCs-TPA/TiO₂ (x = 1%, 2.5%, 5%, 7.5%, and 10%) were tested under UV light, and the most effective catalyst was determined as 2.5% Cs-TPA/TiO₂, achieving a color removal efficiency of 99.57%. Using the 2.5% Cs-TPA/TiO₂ catalyst, which exhibited the highest dye removal efficiency, the effects of reaction time (0–3 h), UV lamp power (8–32 W), initial RB-5 dye concentration (20–40 mg/L), and stirring speed (500–1000 rpm) were individually investigated to determine the optimum operating conditions. Based on the experiments, kinetic studies were carried out using the proven effective 2.5% Cs-TPA catalyst. It was concluded that reaction time, UV lamp power, initial dye concentration, and stirring speed significantly influenced the color removal efficiency. Reusability tests of the 2.5% CsTPA catalyst demonstrated that, after the fourth cycle, a color removal efficiency of 70% was achieved. Characterization results clearly showed that Cs-TPA was successfully hold on to the TiO₂ surface