Inability to remove low-molecular-weight anthropogenic contaminants is a critical issue in low-pressure membrane filtration processes for water treatment. In this work, a novel electrochemical ceramic membrane filtration (ECMF) system using TiO2@SnO2–Sb anode was developed for removing persistent p-chloroaniline (PCA). Results showed that the ECMF system achieved efficient removal of PCA from contaminated waters. At a charging voltage of 3 V, the PCA removal rate of TiO2@SnO2–Sb ECMF system under flow-through mode was 2.4 times that of flow-by mode. The energy consumption for 50% of PCA removal for TiO2@SnO2–Sb ECMF at 3 V under flow-through mode was 0.38 Wh/L, much lower than that of flow-by operation (1.5 Wh/L), which was attributed to the improved utilization of the surface adsorbed HO· and dissociated HO· driven by the enhanced mass transfer of PCA toward the anode surface. Benefiting from the increased production of reactive oxygen species such as O2•–, H2O2, and HO· arising from excitation of anatase TiO2, TiO2@SnO2–Sb ECMF exhibited a superior electrocatalytic activity to the SnO2–Sb ECMF system. The degradation pathways of PCA initiated by OH· attack were further proposed, with the biodegradable short-chain carboxylic acids (mainly formic, acetic, and oxalic acids) identified as the dominant oxidized products. These results highlight the potential of the ECMF system for cost-effective water purification.
Mei Chen,Junjian Zheng,Ruobin Dai,Zhichao Wu,Zhiwei Wang
A selective electrocatalytic ceramic membrane filtration (ECMF) system was developed using molecular imprinting (MI) TiO 2 @SnO 2 -Sb (MI-TiO 2 @SnO 2 -Sb) anode for selectively eliminating 2,4-dichlorophenoxyacetic acid (2,4-D). The introduction of MI sites enhanced the removal of 2,4-D compared to the control. At a charging voltage of 3 V under flow-by mode, the 2,4-D removal rate of MI-TiO 2 @SnO 2 -Sb ECMF system was 1.91 times that of the control (without MI), attributed to the specific recognition sites (leading to selectivity) and the enhanced reactive oxygen species production in the presence of MI sites. In the coexistence of interferent phenoxyacetic acid herbicides, MI-TiO 2 @SnO 2 -Sb ECMF system also showed higher selective coefficient than the control (without MI). More importantly, flow-through mode could enhance the selectivity since the membrane filtration enhanced the mass transfer of target micropollutant towards MI sites. The imparted selectivity was mainly attributed to the size matching and special interaction between the target molecules and imprinted cavities.
Ti/TiO 2 / SnO 2 -Sb-Ir/SnO 2 -Sb-Ni electrodes modified with three kinds of TiO 2 interlayer materials were fabricated. TiO 2 macroporous membrane (MAc) substrate was prepared by direct calcination, and TiO 2 nanotubes (NTs) and TiO 2 mesoporous membrane (MEs) substrate were fabricated by anodic oxidation under different conditions. The study shows that the TiO 2 -nanotube-based anode reduces crack morphology and provides a larger surface area for loading the electrochemically active materials. TiO 2 -NTs as the optimized interlayer improve the oxygen evolution potential (OEP) from 1.49 to 1.85 V and increase the current density of the oxidation peak from 0.28 to 0.55 mA cm −2 , which enhances the oxidative degradation ability of the electrode. In addition, the service life of the Ti/TiO 2 -NTs/SnO 2 -Sb-Ir/SnO 2 -Sb-Ni electrodes is 3.18 times longer than that of the Ti/SnO 2 -Sb-Ir/SnO 2 -Sb-Ni electrodes according to accelerated life tests. The degradation rate of methylene blue (MB) wastewater with an initial concentration of 20 mg L −1 reaches 99.14% under 5.0 V within 5 min by using Ti/TiO 2 -NTs/SnO 2 -Sb-Ir/SnO 2 -Sb-Ni electrodes, which is 1.67 times more than that of the Ti/SnO 2 -Sb-Ir/SnO 2 -Sb-Ni electrodes. Graphical Abstract
Ti/SnO 2 -Sb-Ir/SnO 2 -Sb-Ni electrodes modified with three kinds of TiO 2 interlayer have been
fabricated. The service life of the optimized Ti/TiO 2 -NTs/SnO 2 -Sb-IrO 2 /SnO 2 -Sb-Ni electrode is
3.18 times longer than that of the Ti/SnO 2 -Sb-Ir/SnO 2 -Sb-Ni electrodes. The degradation rate of
the optimized electrode reaches 99.1 % within 5 min, which is 1.67 times more than that of the
Ti/SnO 2 -Sb-Ir/SnO 2 -Sb-Ni electrodes.
危险品化学品经营许可证（带存储）