Electrocatalytic dechlorination of 2,4-dichlorophenol in aqueous solution on palladium loaded meshed titanium electrode modified with polymeric pyrrole and surfactant

The electrochemically reductive dechlorination of 2,4-dichlorophenol (2,4-DCP) in aqueous solution on palladium/polymeric pyrrole–sodium dodecyl sulfonate film/meshed titanium electrode (Pd/PPy–SLS/Ti electrode) was investigated in this paper. The Pd/PPy–SLS/Ti electrode was prepared by electrodesposition and characterized in terms of surface morphology (SEM), structural feature (XRD), specific surface area (BET) and Pd loading level (ICP-AES). Effects of the dechlorination current and the initial pH value of the solution on the removal efficiency and the current efficiency were studied in the 2,4-DCP dechlorination process on Pd/PPy–SLS/Ti electrode. Effective removal of 2,4-DCP was achieved with removal efficiency of 100% and current efficiency of 33.9% in the presence of 100 mg L−1 2,4-DCP under the conditions of initial pH of 2.36, dechlorination current of 5 mA and dechlorination time of 70 min. The intermediate products were 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP). The final products were mainly phenol. Its further reduction product cyclohexanone was also detected. The stability of the electrode was good that the dechlorination efficiency was maintained at 100% after having been reused 8 times. The stable electrode demonstrated a promising application prospect in dechlorination process with high effectiveness and low cost.

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► Effective dechlorination of 2,4-DCP on surfactant-assisted Pd loaded electrode.
► PPy–SLS composite film led to high catalytic activity and low Pd content.
► Removal efficiency kept 100% after 8 times dechlorination on the stable electrode.
► Dechlorination obeys first order reaction with activation energy of 22.61 kJ mol−1.
► Management of the final solution at neutral benefits the subsequent treatment.