Green synthesis of ZnO nanoparticles and study of their photocatalytic degradation of Rhodamine B

Abstract

In the current study, ZnO NPs were successfully produced using flower extracts of Clitoria ternatea (Ct) and leaf extract of Azadirachta indica (Ai). Zinc acetate dihydrate was used as the precursor. Phyto-components in the extract aided in NP reduction and production. The highest percentage yield, 83 wt.% of NPs was obtained for Ct-ZnO. Characterization techniques, including UV–Vis spectroscopy, FTIR, and PSA, were used to distinguish between ZnO NPs. Ct-ZnO and Ai-ZnO NPs indicated UV-Vis absorption at 370 and 355 nm correspondingly. PS analysis confirmed the average sizes of Ct-ZnO and Ai-ZnO as 90 (±22) and 94 (±22) nm respectively. The degradation of textile dye, Rhodamine B (RhB) in the presence of ZnO photo catalysts and also ZnO bulk particles under solar irradiation was investigated in order to study their photocatalytic efficiency. As a result, it could be established that Ct-ZnO presented the highest degradation efficiency, 98 while Ai-ZnO and ZnO BP 95 and 86 % respectively. Maximum degradation illumination period was 300 min. According to the results of investigation on the effect of catalyst amount and pH on degradation of RhB, it could be established that 0.15 g and pH 9 were optimum for 100 mL of 5 ppm RhB, respectively. It was found that degradation time reduced from 300 to 150 min under optimum conditions. Furthermore, phenol, catechol and hydroquinone, were used to study photocatalytic degradation potential of produced NPs. In conclusion, Ct- ZnO NPs contributed most efficiently to the degradation of industrial dye RhB, phenol and its by-products which cause water pollution.