An electrochemical reduction system was studied for the destruction of persistent organic pollutants (POPs). A two-compartment electrochemical system separated by a cation exchange membrane was adopted. The anolyte was sodium hydroxide solution, which supplied sodium ions as cations to the cathode. The catholyte was a reaction mixture of 1, 2,3 -trichlorobenzene as the model POP, tetrahexylammonium bromide (THAB) as the electrolyte and acetonitrile as the solvent. The characteristic features of this system were the decrease in the amount of organic solvent used by about 50%, and the function of sodium ions as the mediator for electron transfer. The mechanism of dechlorination of the system was elucidated using cyclic voltammetry (CV) and a potentiostatic study, and the effect of sodium ions on the electrocatalytic destruction was also investigated. (C) 2004 Elsevier B.V. All rights reserved.