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In this study, the efficiency of the synthesised Ag/TiO2/Fe3O4 catalyst in the removal of endosulfan and metabolite formation by the photocatalysis process, the effect, and optimisation of the ambient conditions were investigated under UV–C light source. Photocatalysis process for endosulfan removal and degradation to metabolites was optimised with Taguchi experimental design method and the results were evaluated statistically by analysis of variance. Light intensity, amount of catalyst, initial endosulfan concentration, pH, and time were chosen as controllable parameters. The highest S/N ratios on the based on parameters were obtained at 27 W light power, pH 4, 0.5 g/L catalyst amount, 60 min reaction time and 4 mg/L initial endosulfan concentration. Since these values, at which the highest removal rate will be achieved, were not found in the experimental design, a confirmation experiment was performed and the removal was obtained as 93.2%. It was found that the most effective parameters on the removal efficiency were the initial endosulfan concentration and pH, respectively. As a result of analysis of variance, Fcritical values showed that the effects of light power, catalyst amount and reaction time on endosulfan removal were not statistically significant. When the P values are examined, it is seen that there is a significant difference between the initial endosulfan concentration and the levels of the pH factor for endosulfan removal. No formations of endosulfan sulphate, endosulfan ether, and endosulfan lactone were observed at high concentrations while endosulfan was removed. [ABSTRACT FROM AUTHOR]

In this study, the efficiency of conventional drinking water treatment processes (coagulation-flocculation and chlorination) for endosulfan removal and metabolite formation were investigated. Taguchi experimental design and analysis of variance (ANOVA) were applied using Minitab program. The highest removal efficiency was obtained as 65% at 6 mg/L initial endosulfan concentration, 30 mg/L aluminium sulfate dose and pH 7, in the coagulation-flocculation experiments. In chlorination experiments, it was determined that the variables of initial endosulfan concentration, chlorine dose, pH and contact time contributed 55.84%, 21.25%, 5.74% and 3.48% to the endosulfan removal, respectively, according to the ANOVA results. The presence of endosulfan metabolites like endosulfan ether, sulfate, and lactone were also detected and measured. P values were obtained only in endosulfan sulfate formation as a result of chlorination, lower than 0.05 for initial endosulfan concentration, chlorine dose and time parameters; apart from this, P values were not statistically significant in all other experiments. [ABSTRACT FROM AUTHOR]