Investigation of the removal of direct yellow 86 dye from aqueous solutions with titanium dioxide and zinc oxide photocatalysts

Wastewaters containing dye cause changes in the flora and fauna of the environment, leading to the disruption of ecological balance. They have negative effects on the aesthetic appearance, light transparency, and gas solubility of water environments, hindering the growth and photosynthesis of living organisms. Additionally, depending on their concentrations and durations in the environment, they exhibit acute and chronic harmful effects on organisms. Within the scope of the thesis, the removal of Direct Yellow 86 dye, which is widely used in the textile industry, was investigated using the photodegradation method. Experiments were conducted in a batch-operated column-type reactor, and titanium dioxide and zinc oxide were used as catalysts. In the first part of the study, the effects of initial dye concentration, catalyst concentration, pH, air flow rate, and temperature on the photodegradation and Total Organic Carbon removal efficiency were investigated. The optimum operating conditions for TiO2 were determined as pH: 6, dye concentration: 200 mg L-1, air flow rate: 0,2 L-1 min, catalyst concentration: 2g L -1, temperature: 40 oC. For ZnO, the optimum conditions were found to be pH:7. dye concentration: 100 mg L-1, air flow rate: 0,2 L min -1, catalyst concentration: 2g L -1, temperature 40 oC. In the second part of the studies, the process was optimized with the initial dye and catalyst concentrations and reaction time variables using the response surface method. In the final part of the study, the reaction kinetics were examined, and the performance of the method in synthetic wastewater was investigated by applying the process to synthetic wastewater containing Direct Yellow 86 dye.