Improved degradation of the aqueous flutriafol using a nanostructure macroporous PbO2 as reactive electrochemical membrane

- The role of structure of 3DEM-PbO2 REM on electrochemical removal of FTF in the EFR was studied.
- The ·OH utilization rate was significantly improved with large oxidation capacity and enhanced mass transfer by EFR.
- 3DEM-PbO2 REM operated in EFR is efficient for the polishing of effluent containing FTF.

In order to develop an electrochemical technology with low-energy consumption for water treatment applications, we fabricated a novel reactive electrochemical membrane (REM) operated in cross-flow filtration mode. The REM with three-dimensional ordered macroporous PbO2 (3DEM-PbO2) film was synthesized via templated deposition that was based on a porous Ti substrate. Compared to conventional flat Ti/PbO2 (F-Ti/PbO2) electrode, the 3DEM-PbO2 possessed larger specific surface area (38.89 m2 g−1), higher oxygen evolution potential (OEP, 1.9 V), larger Voltammetric charge (238 mC cm−2) and smaller electron transfer resistance (1.43 Ω). Furthermore, advection-enhanced mass transfer was obtained when the 3DEM-PbO2 REM is operated in an electrochemical filtration reactor (EFR), relative to a traditional batch reactor (BR). The electrochemical mineralization experiments with flutriafol (FTF) demonstrated that the 3DEM-PbO2 REM operated in the EFR was active for FTF and TOC removal at a low current density of 5 mA cm−2. The oxidation current efficiency of REM operated in a EFR was much higher than that of conventional electrochemical system, and the corresponding energy consumption was lower (0.0505 kWh g−1 FTF, at FTF removal of 75%). The hydroxyl radicals (·OH) production and its utilization rate of the REM was significantly improved, resulting from a combination of the strong catalytic activity of 3DEM-PbO2 and the enhanced mass transfer by filtration mode. Furthermore, computational fluid dynamics (CFD) method was carried out to help explain the improvement of oxidation performance with 3DEM-PbO2 REM in a EFR. Eventually, the electrocatalysis experiments of practical wastewater demonstrated the extreme promise of 3DEM-PbO2 REM for tailwater advanced treatment applications.

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