Photocatalytic and therapeutic applications of the synthesized nickle oxide (NiO) nanoparticles

Nickel oxide (NiO) nanoparticles (NPs) synthesized by co-precipitation method were characterized by UV–Vis, XRD, EDX, SEM and FTIR techniques. XRD analysis revealed partially cubic crystal structure of NiO NPs, with an average particle size of 35.67 nm. The prepared NPs were also used for the photodegradation of Rose Bengal (RB), Carmine and Bromothymol Blue (BB) dyes. The activation energies calculated for the photodegradation reactions were 9.54 kJ/mol, 11.68 kJ/mol and 11.2 kJ/mol, respectively, for RB, Carmine and BB dyes. The first-order reaction kinetics was followed by the photodegradation reaction of three dyes over NiO NPs as a catalyst. The effect of different reaction parameters was also studied, i.e., at pH 4, and time duration of 240, 160 and 200 min about 92%, 90% and 91% degradation was found for RB, Carmine and BB, respectively. Low dye concentration (10 ppm), maximum catalyst dosage (0.05 g) and increase in temperature up to 50 °C were found to facilitate dye degradation. The recyclability study revealed that NiO NPs could be reused for the degradation of selected dyes; however, the first recovery's performance was superior to the second recovery. The results also indicated that with increase in the concentration of NPs from 2- to 4-mg antioxidant activities, Catalase activity (CAT), Superoxide dismutase activity (SOD), Peroxidase activity (POD) and Reduced glutathione (GSH) activity also increased.