Local O<sub>2</sub> concentrating boosts the electro-Fenton process for energy-efficient water remediation.

Xu, Bincheng; Lin, Ze; Li, Fengting; Tao, Tao; Zhang, Gong; Wang, Ying · Proc Natl Acad Sci U S A · 2024

basic_science · Level V

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Abstract

The electro-Fenton process is a state-of-the-art water treatment technology used to remove organic contaminants. However, the low O<sub>2</sub> utilization efficiency (OUE, <1%) and high energy consumption remain the biggest obstacles to practical application. Here, we propose a local O<sub>2</sub> concentrating (LOC) approach to increase the OUE by over 11-fold compared to the conventional simple O<sub>2</sub> diffusion route. Due to the well-designed molecular structure, the LOC approach enables direct extraction of O<sub>2</sub> from the bulk solution to the reaction interface; this eliminates the need to pump O<sub>2</sub>/air to overcome the sluggish O<sub>2</sub> mass transfer and results in high Faradaic efficiencies (~50%) even under natural air diffusion conditions. Long-term operation of a flow-through pilot device indicated that the LOC approach saved more than 65% of the electric energy normally consumed in treating actual industrial wastewater, demonstrating the great potential of this system-level design to boost the electro-Fenton process for energy-efficient water remediation.