Reductive dehalogenation of a chloroacetanilide herbicide in a flow electrochemical cell fitted with Ag-modified Ni foams

BACKGROUND: The aim of this work is to adapt the electrochemical reduction of Alachlor(TM), using Ag-modified Ni foam electrodes to environmental applications. In this context, preparative electrolyses of Alachlor(TM) were performed in a flow electrochemical cell in different electrolytic media. RESULTS: The highest catalytic activity for the reduction of Alachlor(TM) was obtained in 0.05 mol L-1 NaOH, with a conversion yield of 93%. The dechlorination yield of Alachlor(TM) estimated from the Cl- concentration was 77%, significantly lower than its conversion yield, but higher than the yield of deschloroalachlor (69%), the main dehalogenated by-product, indicating the presence of other by-products. CONCLUSIONS: Total reduction of Alachlor(TM) was achieved in conditions adapted to environmental applications, showing that this process can be used for dechlorination treatment of Alachlor(TM) in aqueous media. Although a high dechlorination yield was obtained, biodegradability estimated from BOD5 measurements remained low, showing that the C-Cl bond is not the only functional group that is responsible for the biorecalcitrance of Alachlor(TM).