Design and operation of a solid polymer electrolyte reactor for electrochemical hydrodehalogenation

A solid polymer electrolyte reactor is designed for the electrochemical hydrodehalogenation (HDH) of halogenated organic compounds in oil and/or aqueous solutions. The reactor has been evaluated at 0.05, 0.1, 0.2, 1 and 2 dm(3) scales under various conditions and its effectiveness has been demonstrated experimentally using the HDH of 2,4-dichlorophenol (DCP) and 2,4-dibromophenol (DBP) as model reactions of environmental interest. The HDH of low concentration DCP and DBP in oil solutions in the reactor achieved conversions up to 35% within 3-4 h with current efficiencies up to 26%, space-time yields up to 0.70 (kg DCP or DBP) m(-3) h(-1) and energy consumptions of 4.7 kWh (kg DBP or DCP)(-1). With the concentrated DCP or DBP-oil solutions, the performances were significantly improved, i.e. current efficiencies of 60-85%, space-time yields of 1.5-5.6 (kg DCP or DBP) m-3 h-1 and energy consumptions of 1.5-2.4 kW h (kg DCP or DBP)(-1). The HDH of DCP and DBP in the aqueous solutions was compared to the paraffin oil media and the reactor stability was evaluated for operating times of up to 170 h. (C) 2004 Elsevier B.V. All rights reserved.