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Ambient-pressure-dried (APD) crack-free Sb-SnO2 xerogel has been developed through a facile sol-gel approach. Propylene oxide was added into the tin and antimony precursors to cause rapid formation of the wet gel, which was then modified with silica and dried under ambient pressure. A silica modification carried out by soaking the wet gel in TEOS/ethanol solution, in combination with solvent exchange, allowed to avoid the risky and costly supercritical drying (SCD) process. The silica possessed dual-functional effects during the synthesis process as surface silylation agent and underlying silica structure. FT-IR, SAXS, TEM, and nitrogen physisorption analysis revealed a favorable silica dispersion, outstanding specific surface area (254 m2 g−1), pore volume (0.52 cm3 g−1), and ideal pore size (8.75 nm) for the products. The key properties of the APD crack-free Sb-SnO2 xerogel were compared with that of SCD aerogel at the same synthesis conditions. Finally, the electrochemical behaviors of 3D electrochemical system filled with the as-synthesized materials as particle electrodes were investigated, which with regard to voltammetric charge and polarization impedance. Padding of the crack-free Sb-SnO2 xerogels yielded a voltammetric charge 2.99 times as large as that of conventional electrochemical system, and decreased the charge transfer resistance from 46.19 to 6.39 Ω, which realize intrinsically enhanced electrochemical performance for 3D electrochemical system. [ABSTRACT FROM AUTHOR]

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 PbO 2 (3DEM-PbO 2 ) film was synthesized via templated deposition that was based on a porous Ti substrate. Compared to conventional flat Ti/PbO 2 (F-Ti/PbO 2 ) electrode, the 3DEM-PbO 2 possessed larger specific surface area (38.89 m 2 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-PbO 2 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-PbO 2 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-PbO 2 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-PbO 2 REM in a EFR. Eventually, the electrocatalysis experiments of practical wastewater demonstrated the extreme promise of 3DEM-PbO 2 REM for tailwater advanced treatment applications. [ABSTRACT FROM AUTHOR]

Diffusion in electrochemistry is a critical issue for water purification. Electrocatalytic reactor system in improving water quality is a useful way to induce convection to enhance diffusion. This study focuses on the preparation and the characterization of Ti/SnO 2 –Sb tubular porous electrode for degrading pyridine wastewater. The electrode as an anode in reactor system is prepared by coating SnO 2 –Sb as an electro-catalyst via Pechini method on the tubular porous Ti. Scanning Electron Microscopy, Energy Dispersive Spectrum, X-ray Diffraction and Pore Distribution are employed to evaluate the structure and morphology of the electrodes coatings, and Linear Sweep Voltammetry and Cyclic Voltammetry are used to illustrate the electrochemical properties of the electrodes coatings. Furthermore, the electrochemical oxidation performance of Ti/SnO 2 –Sb tubular porous electrode is characterized by degrading pyridine wastewater. The effects of flow and static pattern, initial pyridine concentration, supporting electrolyte concentration, current density and pH on the performance of the reactor were investigated in the electrocatalytic reactor system. The results indicated that the removal ratio of pyridine reaches maximum which is 98% under the optimal operation conditions, that are 100 mg L −1 initial pyridine concentration, 10 g L −1 supporting electrolyte concentration, 30 mA cm −2 current density and pH 3. Transition state calculation based on the density function theory was combined with High Performance Liquid Chromatography, Gas Chromatography and Ionic Chromatography results to describe the pathway of pyridine degradation. [ABSTRACT FROM AUTHOR]