Photocatalytic processes associated with degradation of pesticides in aqueous solutions: Systematic review and meta-analysis

Extensive use of pesticides and their slow degradation have resulted in contamination of environment, which inflicts damages on the ecosystem and human health. The presence of pesticides in aqueous media is of a global concern. Photocatalytic processes have gained a lot of attention over the last decades with regard to degradation of pesticides. This study is aimed at reviewing the most relevant reports on the application of the photocatalytic process involved in the degradation of pesticides in aqueous solutions. Moreover, the effects of influential var-iables such as catalyst amount, pH, concentration of pesticides, light intensity and contact time were discussed in detail. Within this study, three subgroups of pesticides were reviewed, namely insecticides, herbicides and fungicides. Meta-analysis was also conducted by the random-effects model. In addition, statistical analyses were accomplished by the R software. After the screening process, 22 articles were found to be suitable in the meta- analysis. Results of meta-analysis proved that the photocatalytic processes could remove pesticides with an average acceptable degradation efficiency of 93.36%. The average pooled percent of photocatalytic processes for the degradation of insecticides, herbicides and fungicides was 93.35 (95% CI: 89.89-96.81), 90.73 (95% CI: 80.44-101.02) and 100 (95% CI: 98.12-101.88), respectively. The results of the Begg's test (z = 0.4903, P = 0.6239) indicated that no bias regarding the potential publication was detected. Finally, it was demonstrated that photocatalytic processes are highly appropriate for the degradation of pesticides from aqueous solutions.