▎ 摘　　要

In this study, the photocatalytic decomposition of diazinon using graphene/ZnO nanocomposite doped with manganese was studied under UV light (UV reactor with low pressure mercury lamp 15 W) and sunlight. The effects of nanocomposite concentrations in the range of 50-200 mg/L, pH of the solution ranging from 3 to 11, diazinon concentrations in the range of 10-90 mg/L, and various contact times (20-120 min) were investigated to find the optimal conditions for diazinon decomposition. The results indicated that the photocatalytic efficiency in diazinon decomposition was 85.2% under optimal conditions (UV lamp, pH: 7, diazinon initial concentration: 10 mg/L, nanocomposite concentration: 100 mg/L, contact time: 120 min). The process efficiency under optimal conditions for the maximum removal of diazinon in the presence of sunlight was about (pH: 7, initial diazinon concentration: 10 mg/L, nanocomposite concentration: 200 mg/L and contact time: 120 min). Findings also showed that the photocatalytic process for the removal of diazinon from aqueous solutions using UV lamp radiation had a better performance than that of sunlight.