Degradation and mineralization of diazinon pesticide in UVC and UVC/TiO₂ process

Abstract

The performance of photolytic and photocatalytic degradation and mineralization of diazinon in water using UVC and UVC/TiO₂ process in batch condition was investigated, determining the effects of different parameters. The best pH in removal of diazinon by UVC-Photolysis and UVC/TiO₂ process is equal to 5 and optimum amount of catalyst was calculated as 150 mg/L. The results showed that diazionon completely degraded after 30 min at 100 mg/L TiO₂ and pH 5. The presence of anionic species promoted the photolysis efficiency to degrade diazinon from 52 to 80%, lowering the UVC/TiO₂ ability to degrade and mineralize diazinon from 97 to 62%, on the other hand. Mineralization of diazinon by photocatalyst process proved to be 2.5 times higher than of photolysis. Moreover, the reduction pattern in the photocatalysis and photolysis processes were better described by pseudo-first- and second-order kinetics model with a reaction rate constant of 0.094 and 0.0029, respectively.

Keywords:

• UV irradiation
• Photocatalysis
• TiO₂ nanoparticle
• Diazinon

Acknowledgment

The authors gratefully acknowledge the financial and technical support provided by the Tarbiat Modares University, Tehran, Iran.