Study on degradation of herbicides with chlorine dioxide

Abstract

The aim of this study was to investigate and optimize degradation of herbicides (such as bentazone and thifensulfuron-methyl) with chlorine dioxide in deionized water. Degradation of herbicides was examined in deionized water with different amount of chlorine dioxide (5 and 10 ppm), different time of degradation (30 min, 1 h, 2 h, 3 h, 6 h and 24 h), at different pH (3, 7 and 9) and under light or dark conditions, while concentration of herbicides was 10 ppm. Degradation efficiency of herbicides was followed using HPLC-DAD. Major degradation products were identified using GC/MS analysis. The best degradation efficiency of bentazone was achieved by treatment with 10 ppm of chlorine dioxide under light, after 24 h of initial treatment, at pH of 3 and 7, and it was 92%. In the case of a thifensulfuron-methyl herbicide, the best efficiency of degradation was achieved by treatment with 10 ppm of chlorine dioxide under light, after 24 h of initial treatment, and it was 73%. Toxicological analysis using Daphnia magna was performed for degradation products 1, 6 and 24 h after the treatment with chlorine dioxide.