Evaluation of the technoeconomic feasibility of electrochemical hydrogen peroxide production for decentralized water treatment

This study evaluated the feasibility of electrochemical hydrogen peroxide (H2O2) production with gas diffusion electrode (GDE) for decentralized water treatment. Carbon black-polytetrafluoroethylene GDEs were prepared and tested in a continuous flow electrochemical cell for H2O2 production from oxygen reduction. Results showed that because of the effective oxygen transfer in GDEs, the electrode maintained high apparent current efficiencies (ACEs,> 80%) for H2O2 production over a wide current density range of 5-400 mA/cm(2), and H2O production rates as high as similar to 202 mg/h/cm(2) could be obtained. Long-term stability test showed that the GDE maintained high ACEs (>85%) and low energy consumption (< 10 kWh/kg H2O2) for H2O2 production for 42 d (similar to 1000 h). However, the ACEs then decreased to similar to 70% in the following 4 days because water flooding of GDE pores considerably impeded oxygen transport at the late stage of the trial. Based on an electrode lifetime of 46 days, the overall cost for H2O2 production was estimated to be similar to 0.88 $/kg H2O2, including an electricity cost of 0.61 $/kg and an electrode capital cost of 0.27 $/kg. With a 9 cm GDE and 40 mA/cm(2) current density, similar to 2-4 mg/L of H2O2 could be produced on site for the electro-peroxone treatment of a 1.2 m(3)/d groundwater flow, which considerably enhanced ibuprofen abatement compared with ozonation alone (similar to 43%-59% vs. 7%). These findings suggest that electrochemical H2O2 production with GDEs holds great promise for the development of compact treatment technologies for decentralized water treatment at a household and community level. (C) Higher Education Press 2020