Determination of methylene blue dye degradation by photocatalytic and sonocatalytic methods

Coloured wastewater generated by various industeries such as paper, textile, rubber and plastic if discharged into the environment without any treatment cause many problems. Existence of small amounts of dye affects the optical properties of water and just the first pollutant that is visible in water. It is necessary to remove waste water due to the complex structure and toxicity and carcinogenic nature. In recent years, many techniques have been developed to remove these contaminants from water. In this study, zinc oxide nanoparticles were first synthesized by sol-gel method. XRD and SEM analyzes are performed on nanoparticles. In the next step, the efficiency of ZnO as a photocatalyst was investigated to remove the methylene blue MB dye from a 10 ppm constant aqueous solution with a volume of 50 ml with UV light (15 watts). The results of the experiment were evaluated for three value of catalysts 0.03, 0.05 and 0.07 gr, and three value of Ph 4, 7.5 and 11. The best photocatalytic degradation was at PH = 11 and 0.77 gr at 91%, indicating an increase in photocatalytic activity in alkaline phases with higher ZnO catalyst contents. Also, the effect of methylene blue degradation was evaluated optimally by sonocatalytic method. Thus, the effect of ultrasound on dye degradation with ZnO catalyst with powers of 150,250 and 350 in 3 times intervals of 30, 60 and 90 minutes was investigated. The results showed the best dye degradation at 350 and 90 minutes, with 38%. The analysis of the results shows that with increased power of ultrasound and increasing time, a higher degradation occurs. Comparing two degradation methods in terms of time intervals and identical testing conditions, the Photocatalytic method shows a higher efficiency compared to the Sonocatalyst method