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

This study evaluated the feasibility of electrochemical hydrogen peroxide (H 2 O 2 ) 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 H 2 O 2 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 H 2 O 2 production over a wide current density range of 5–400 mA/cm 2 , and H 2 O 2 production rates as high as ∼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 H 2 O 2 ) for H 2 O 2 production for 42 d (∼1000 h). However, the ACEs then decreased 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 H 2 O 2 production was estimated to be ∼0.88 $/kg H 2 O 2 including an electricity cost of 0.61 $/kg and an electrode capital cost of 0.27 $/kg. With a 9 cm 2 GDE and 40 mA/cm 2 current density, ∼2–4 mg/L of H 2 O 2 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 (∼43%–59% vs. 7%). These findings suggest that electrochemical H 2 O 2 production with GDEs holds great promise for the development of compact treatment technologies for decentralized water treatment at a household and community level.