Electrochemical Dechlorination of Gaseous Trichloroethylene to Nonchlorinated Value-Added Products Using a Cu/Ni Alloy Electrode with a Gel Membrane Interface.

Trichloroethylene (TCE) is widely used in various industrial applications, leading to significant environmental and public health concerns due to its toxicity and persistence. Current nonthermal liquid-phase TCE treatment methods, including electrochemical processes, typically produce liquid byproducts that require additional separation steps, limiting their efficiency. To overcome these challenges, this study introduces an innovative electrochemical approach for the direct conversion of TCE gas into less harmful gaseous products, utilizing a Cu/Ni alloy 3D foam electrode integrated with a poly(vinyl alcohol) (PVA)-sodium polyphosphate (SPP) gel membrane system. Our system demonstrated a conductivity of 0.05 S cm-1 in liquid phases at both half-cells, comparable to existing polymeric membranes. Importantly, when no liquid electrolyte was present, the conductivity increased to 0.09 S cm-1, making this setup highly suitable for the direct treatment of gaseous TCE. The removal efficiency was evaluated by varying electrodeposition time and modifying the electrode surface with potassium hydroxide (KOH) and cetyltrimethylammonium chloride (CTAC), resulting in a high TCE removal rate of 0.69 h-1. This enhanced performance is attributed to the Cu/Ni alloy's ability to adsorb and solubilize TCE effectively under these modified conditions. The gas chromatography analysis definitively shows that the TCE was completely dechlorinated, with a removal efficiency of about 75%. This resulted in the conversion of TCE to ethene and ethane with 100% carbon recovery. This gas-to-gas phase conversion strategy eliminates the need for additional separation steps, offering a promising solution for the effective management of chlorinated volatile organic compounds (CVOCs) and reducing environmental hazards.