Electrochemical HDH of chlorinated organics

摘要

The ability to re-cycle halogenated liquid wastes to the process, based on electrochemical hydrodehalogenation (HDH), will provide a significant economic advantage and will reduce the environmental burden. This work shows that electrochemical dechlorination of 2,4-dichlorophenol (DCP) and pentachlorophenol (PCP) using iron cathodes was effective, with almost complete dechlorination possible at low concentrations of DCP and PCP. The use of Pd catalysed iron electrodes markedly improved the dechlorination efficiency. The HDH of DCP and PCP can be achieved quite efficiently using carbon supported Pd cathodes operating with solid polymer electrolyte (SPE) cells using both cation and anion exchange membranes, without a supporting electrolyte. For the low concentrations of organic compounds treated the current efficiencies were quite respectable, ca. 10% ～ 70%. Energy consumptions were reasonable: 6 and 21 kWh/kg for DCP and PCP, respectively. Improvements in the Pd catalyst, particularly in terms of increased surface area and optimisation of bonding should realise improved performance.