Membrane fouling, which is caused by the deposition of particles on the membrane surface or pores, reduces system performance in membrane distillation (MD) applications, resulting in increased operational costs, poor recovery, and system failure. Optical Coherence Tomography enables in-situ foulant monitoring in both 2D and 3D, however, the 2D images can only determine fouling layer thickness in severe fouling. Therefore, in this study, an advanced 3D imaging analysis technique using intensity range filters was proposed to quantify fouling layer formation during MD through the use of a single 3D image. This approach not only reduces computational power requirements, but also successfully separated the fouling layer from the membrane at the microscale. Thus, the thickness, fouling index, and fouling layer coverage can be evaluated in real time. To test this approach, Polyvinylidene fluoride (C-PVDF) and polytetrafluoroethylene (C-PTFE) membranes were used to treat a feed consisting of industrial textile wastewater. Thin and disperse foulants was observed on the C-PTFE, with a 22 µm thick fouling layer which could not be observed using 2D images after 24 h. Moreover, the C-PTFE demonstrated better antifouling ability than the C-PVDF as demonstrated by its lower fouling index, which was also supported by surface energy characterization. This work demonstrates the significant potential of 3D imagery in the long-term monitoring of membrane fouling process to improve membrane antifouling performance in MD applications, which can lead to lowered operational costs and improved system stability.

膜污染是由颗粒在膜表面或孔上沉积引起的，会降低膜蒸馏 (MD) 应用中的系统性能，导致运营成本增加、回收率低和系统故障。光学相干断层扫描使原位2D 和 3D 中的污垢监测，然而，2D 图像只能确定严重污垢中的污垢层厚度。因此，在本研究中，提出了一种使用强度范围滤波器的先进 3D 成像分析技术，通过使用单个 3D 图像来量化 MD 期间的污垢层形成。这种方法不仅降低了计算能力要求，而且还成功地在微尺度上将污垢层与膜分离。因此，可以实时评估厚度、污垢指数和污垢层覆盖率。为了测试这种方法，使用聚偏二氟乙烯 (C-PVDF) 和聚四氟乙烯 (C-PTFE) 膜来处理由工业纺织废水组成的进料。在 C-PTFE 上观察到薄而分散的污垢，具有 22 µm 厚的污垢层，24 小时后使用 2D 图像无法观察到该污垢层。此外，C-PTFE 表现出比 C-PVDF 更好的防污能力，正如其较低的污垢指数所证明的那样，这也得到了表面能表征的支持。这项工作证明了 3D 图像在膜污染过程的长期监测中的巨大潜力，可以提高 MD 应用中的膜防污性能，从而降低运营成本并提高系统稳定性。