The use of pesticides and other chemicals may lead to potential contamination of surface water due to their large amount of application and various ways into water bodies. The treatment system for pesticide-impacted surface water requires easy implementation, maintenance and low cost. This study evaluated a novel, semi-passive activated carbon-based electrochemical system for the destruction of 3 pesticides (fipronil, permethrin and bifenthrin) that are widely reported in surface water in California. The working electrode was prepared using a convenient method. Micro- and nano-scale activated carbon particles were coated on a piece of highly conductive carbon cloth (60 mm X 20 mm X 1mm) to form an electrode with high conductivity and adsorption capacity. When this electrode was placed into a 200 mL chamber containing phosphate-buffered water with 1 ppm fipronil, it could adsorb &gt;90% aqueous fipronil in 2h. Under a voltage of -1 V vs. Standard Hydrogen Electrode for 2 h, 95% of adsorbed fipronil was removed. Chloride was found to be the major product of dehalogenation of fipronil, with a yield of 97%. This electrode is stable over &gt;10 cycles of electrolysis in water without losing its adsorptive capacity and catalytic activity. Different electrolyte solutions and cell configurations were tested using this carbon cloth-based electrode, and no significant difference of fipronil removal were observed under these different conditions, indicating the steady performance of this electrolytic treatment system. These results lay the foundation for an activated carbon-based electrolysis system for treatment of pesticides and other toxic organic compounds in surface water due to the low cost of activated carbon and electricity and the easy preparation and long lifetime of the electrode.

Electrolytic degradation of pesticides in surface water using an activated carbon-based electrode system

253rd National Meeting (2017)

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