Electrochemical transformation of thichloroethylene in groundwater by Ni-containing cathodes

• Stainless steel mesh is a cost-effective cathode material.
• Dense mesh provides large surface area but causes bubble entrapment within pores.
• Increasing the Ni content in stainless steel positively influences TCE removal.

In this study, we evaluate the use of different stainless steel (SS) materials as cost-effective cathode materials for electrochemical transformation of trichloroethylene (TCE) in contaminated groundwater. Ni, which is present in certain SS, has low hydrogen overpotential that promotes fast formation of atomic hydrogen and, therefore, its content can enhance hydrodechlorination (HDC). We a flow-through electrochemical reactor with a SS cathode followed by an anode. The performance of Ni containing foam cathodes (Fe/Ni and Ni foam) was also evaluated for electrochemical transformation of TCE in groundwater. SS type 316 (12% Ni) removed 61.7% of TCE compared to 52.6% removed by SS 304 (9.25% Ni) and 37.5% removed by SS 430 (0.75% Ni). Ni foam cathode produced the highest TCE removal rate (68.4%) compared with other cathodes. The slightly lower performance of SS type 316 mesh is balanced by the reduction in treatment costs for larger-scale systems. The results prove that Ni content in SS highly influences TCE removal rate.