Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China.
Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.
Environ Sci Technol. 2023 Dec 5;57(48):20421-20430. doi: 10.1021/acs.est.3c07448. Epub 2023 Nov 16.
A flow-through anode has demonstrated high efficiency for micropollutant abatement in water purification. In addition to developing novel electrode materials, a rational design of its porous structure is crucial to achieve high electrooxidation kinetics while sustaining a low cost for flow-through operation. However, our knowledge of the relationship between the pore structure and its performance is still incomplete. Therefore, we systematically explore the effect of pore size (with a median from 4.7 to 49.4 μm) on the flow-through anode efficiency. Results showed that when the pore size was <26.7 μm, the electrooxidation kinetics was insignificantly improved, but the permeability declined dramatically. Traditional empirical evidence from hydrodynamic modeling and electrochemical tests indicated that a flow-through anode with a smaller pore size (e.g., 4.7 μm) had a high mass transfer capability and large electroactive area. However, this did not further accelerate the micropollutant removal. Combining an overpotential distribution model and an imprinting method has revealed that the reactivity of a flow-through anode is related to the catalytically active volume/sites. The rapid overpotential decay as a function of depth in the anode would offset the merits arising from a small pore size. Herein, we demonstrate an optimal pore size distribution (∼20 μm) of typical flow-through anodes to maximize the process performance at a low energy cost, providing insights into the design of advanced flow-through anodes in water purification applications.
流通式阳极在水净化中对微污染物的去除具有高效性。除了开发新型电极材料外，合理设计其多孔结构对于实现高电氧化动力学同时保持流通操作的低成本至关重要。然而，我们对孔结构与其性能之间的关系的了解仍然不完整。因此，我们系统地研究了孔径（中值为 4.7 至 49.4μm）对流通式阳极效率的影响。结果表明，当孔径<26.7μm 时，电氧化动力学没有显著提高，但渗透性急剧下降。传统的水动力模型和电化学测试的经验证据表明，具有较小孔径（例如 4.7μm）的流通式阳极具有高传质能力和大的电化学活性面积。然而，这并没有进一步加速去除微污染物。结合过电势分布模型和压印方法，发现流通式阳极的反应性与催化活性体积/位点有关。阳极中深度的快速过电势衰减会抵消小孔径带来的优点。在此，我们展示了典型流通式阳极的最佳孔径分布（约 20μm），以在低能耗下最大程度地提高工艺性能，为水净化应用中先进的流通式阳极的设计提供了见解。
