Hydrodehalogenation of Polychloromethanes on Silver-Based Gas Diffusion Electrodes

This work reports the electroreduction of a volatile organic halide (trichloromethane) from an airborn stream. In the past years, we highlighted the role of polycrystalline silver as powerful electrocatalyst for the electroreductive hydrodehalogenation of volatile organic halides (VOH) in water/organic solvent mixtures, from 0 to 100 % of the aqueous component. The successful conversion of trichloromethane and 1,1,1-trichloethane to the relevant dehalogenated compounds, methane and ethane have prompted us to extend the investigations to the treatment of gaseous effluents, adopting a silver Gas Diffusion Electrode (Ag-GDE) and the appropriate cell design. In the field of electroreduction processes the possibility of using GDE to treat gaseous effluents for the removal of volatile organic pollutants represents an electrochemical challenge, and the treatment of N-2/CHCl3 gas mixtures fed into the cathodic Ag-GDE compartment demonstrates the feasibility of the electroreductive detoxification process. Our results will be presented and discussed in terms of CHCl3 removal efficiency, selectivity and energy consumption in preparative electrolyses.