Green Synthesis of Ag-NiO and Investigation of its Catalytic Activity for Degradation of Rhodamine B Dye in Aqueous Medium

The plants assisted green synthesis of nanoparticles have drawn a momentous importance worldwide. NiO is one the metal oxides researched comprehensively for decades and still has dominance in the field of photo-catalysis. In present study NiO and Ag-NiO were successfully prepared by a simple and environmentally friendly method using nickel nitrate, silver nitrate and leaves extract of Azadirachta indica L. plant as precursor materials. The prepared materials were characterized by XRD, SEM and TGA. Then the photo-catalytic efficiency of NiO and Ag-NiO were evaluated by aqueous phase photo-degradation of rhodamine B as a model pollutant under ultraviolet irradiations. About 40% and 96% of 200 mg/L (50 mL) degraded in 120 min at 40 °C over NiO and Ag-NiO as photo-catalyst respectively. The apparent rate constants were determined as 0.0109, 0.0165, 0.0175 and 0.0190 per min at 30, 40, 50 and 60 °C respectively. 14.6 kJ/mol was calculated as activation energy of reaction.