The photocatalytic removal of diazinon from aqueous solutions using tungsten oxide doped zinc oxide nanoparticles immobilized on glass substrate

Abstract

Diazinon is an important organophosphorus pesticide with extensive use, which is considered to be a major health hazard for humans due to its adverse effects on cholinesterase activity and central nervous system. The entry of diazinon into water resources affects a wide range of non-target organisms, which highlights the importance of its removal from water resources. The present study aimed to synthesize and use WO3 doped ZnO nanocatalyst to degrade diazinon. Zinc oxide nanoparticles were synthesized using the hydrothermal method and doped with 0.5%, 1%, and 2% M tungsten oxide. Moreover, the effects of dopant percentage, pH, the initial concentration of diazinon, nanoparticle dosage, and contact time were investigated. The results of EDS revealed that W was doped into ZnO structure. The maximum diazinon degradation (99%) was obtained using 10 mg/cm−2 2% WO3 doped ZnO, 10 mg/l diazinon, neutral pH value and contact time of 180 min. Removal efficiency was decreased by increasing pH and initial diazinon concentration. The experimental kinetic data followed the pseudo-first order model. The reaction rate constant (kobs) was decreased from 0.0205 to 0.0034 1/min with increasing initial diazinon concentration from 10 to 200 mg/L, respectively. The figures of merit based on electric energy consumption (EEO) indicate that less energy is consumed during the degradation of diazinon in the presence of 2% WO3 doped ZnO compared with other photocatalysts. Therefore, it could be concluded that 2%WO3 doped ZnO is a promising material for photocatalytic degradation of diazinon with high efficiency under optimal condition.