Data underlying the publication: Advanced ceramics in radical filtration: TiO2 layer thickness effect on the photocatalytic membrane performance

Membranes with advanced oxidation processes (AOPs) are a promising combination to separate and degrade organic pollutants in a single system. In this work, we describe the fabrication and characteristics of nine membranes with different TiO2 top layer thicknesses (from 0.26 to 21.9 μm), giving attention to the critical catalyst thickness and the formation of defects. We also report the optimum photocatalyst thickness for our single-layer membranes (∼2.74 μm), after which more titanium dioxide does not improve the degradation. However, an increase in degradation for membranes with multiple TiO2 layers was still possible. These results and the comparisons with the literature suggested that the optimal catalyst thickness is closely related to the material morphology. We obtained a maximum degradation at the lower filtration rate (1.6 L m−2 h−1) of 72% with a single layer membrane of 3.4 μm and 82% with a membrane with six layers of 21.9 μm. Furthermore, a 1D mass transport and reaction model that describes the coating thickness effect was developed and fitted with the experimental data. Other parameters are also discussed, such as light penetration limitations, surface area, and surface reaction rate constant. These results and analysis provide a better understanding of the fabrication and optimization of photocatalytic membranes.

结合高级氧化工艺（Advanced Oxidation Processes, AOPs）的膜材料是一种极具应用前景的一体化系统，可在单一体系中同时实现有机污染物的分离与降解。本研究中，我们制备了9种顶层TiO₂厚度各异的膜材料（厚度范围0.26~21.9 μm），重点关注了关键催化剂厚度与缺陷的形成机制。我们还确定了单层膜的最优光催化剂厚度（约2.74 μm），当厚度超过该阈值后，进一步增加二氧化钛负载量无法提升降解性能；但对于多层TiO₂膜而言，继续增加层数仍可改善降解效果。结合实验结果与文献对比分析可知，最优催化剂厚度与材料形貌密切相关。在较低过滤速率（1.6 L·m⁻²·h⁻¹）条件下，厚度3.4 μm的单层膜最高降解率可达72%，而由6层组成、总厚度21.9 μm的复合膜最高降解率可达82%。此外，我们构建了可描述涂层厚度影响的一维传质反应模型，并将其与实验数据进行拟合验证。本研究还探讨了其他关键参数，包括光穿透限制、比表面积以及表面反应速率常数。上述结果与分析可为光催化膜的制备与优化提供更为深入的理论参考。