Study of the Decomposition in Carbofuran by Fenton and Ultrasonic Processes

摘要

Carbofuran (C12H15NO3) is one of the most toxic carbamates pesticides, which is used to control insects in a wide variety of field crops including potatoes, corn and soybeans. In this study, Fenton process and ultrasonic process were applied to degrade carbofuran from aqueous system by batch experiments. Initial carbofuran concentration was designed at 10 to 50 mg/L and the additions of ferrous and hydrogen peroxide were between 0 to 10 mg/L and 0 to 200 mg/L, respectively. The initial pH value was 3 and the reaction temperature was 25oC. Experimental results indicate that the decomposition efficiencies of carbofuran by Fenton process are more than 90% but around 40% by ultrasonic process. In addition, mineralization of carbofuran observed by the decrease in total organic carbon (TOC) was less than 43% by Fenton process and less than 15% by ultrasonic process. As the addition of ferrous or hydrogen peroxide increased, a better decomposition efficiency of carbofuran by Fenton process and ultrasonic process was observed. Three kinds of intermediates proposed by other researches including 1,4-Benzenedicarboxaldehyde anion, 7-Benzofuranol, 2,3-dihydro-2,2-dimethyl and 7-hydroxy-2,2-dimethyl-benzofuran-3-one were determined after the carbofuran treatment by Fenton and ultrasonic process. Therefore, the possible reaction mechanisms of carbofuran decomposition could be developed.