Photocatalytic treatment of N-Nitrosomorpholine by undoped TiO2-ZnO & Si-doped TiO2-ZnO nanocatalyst

Abstract

Photocatalytic degradation reactions of N-Nitrosomorpholine in an aqueous solution using nano anatase TiO₂-ZnO & Si-TiO₂-ZnO have been studied. The photocatalysts have been prepared by sol-gel method and characterised using SEM, EDX, XRD, FT-IR, UV, BET & TEM techinques. The loops seen in the BET study exhibited hysteresis following a type IV isotherm. The degradation process has been examined under various conditions including dark, induced light, UV light, direct sunlight, and sonicator in the presence of sunlight as the energy source. A decrease in band gap is observed for Si-TiO₂-ZnO as compared undoped TiO₂-ZnO, which results in improved photocatalytic activity in the doped sample. The Si-TiO₂-ZnO exhibited the highest level of photocatalytic activity when subjected to sonication in the presence of sunlight. The effects of several parameters, such as pH, pollutant concentration, and catalyst dose, the reaction rate etc. have been examined. Under optimal conditions, the pollutant underwent degradation and exhibited a degradation efficiency of 96% using Si-TiO₂-ZnO photocatalyst. The photocatalyst exhibits excellent stability when recycled for about four cycles. The remarkable efficiency of Si-TiO₂-ZnO under sunlight exposure highlights the extensive range of applications for photocatalysts in the removal of pollutants during water purification.