Although robust models on water transport across reverse osmosis (RO) membranes exist, detailed mechanistic insights of mineral scaling in the active polyamide (PA) layer, especially through visual investigations, are still lacking. Herein, a holistic approach of imaging the onset of mineral scales in the PA-layer is detailed at different length scales. BW30 RO membranes were scaled by running CaCO₃-rich feedwater in a narrow, spacer-filled crossflow channel for 120 min. Then, microscopy and spectroscopy-based characterization tools were applied to investigate the CaCO₃ scaling in the PA-layer. The vaterite phase of CaCO₃ dominated at the incipient stage and was amplified at higher flux. TEM imaging, followed by digital staining with unsupervised K-means clustering, demonstrated incipient scaling primarily on top of the intricate folds of the PA-layer. Scales with a characteristic size between 1 and 6 nm were also identified deep inside the randomly distributed microvoids formed by those folds, hinting at heterogeneous crystallization of CaCO₃. Thus, membranes designed to limit the complex folding of the PA-layer could show more scale resistance. The improved visualization of PA-layer via TEM–K-means and resulting insights can be broadly used in designing novel scale-resistant membranes and evaluating the efficacy of membrane cleaning operations.

尽管存在关于跨反渗透 (RO) 膜的水传输的可靠模型，但仍然缺乏对活性聚酰胺 (PA) 层中矿物质结垢的详细机理见解，尤其是通过视觉调查。在这里，在不同的长度尺度上详细描述了一种对 PA 层中矿物尺度的开始进行成像的整体方法。BW30 RO 膜通过将富含 CaCO ₃的给水在狭窄的、填充有隔板的错流通道中运行 120 分钟进行缩放。然后，应用显微镜和基于光谱的表征工具来研究PA 层中的 CaCO _{3结垢。CaCO 3}的球霰石相在初始阶段占主导地位，并在较高通量时被放大。TEM 成像，然后是无监督 K 均值聚类的数字染色，主要在 PA 层的复杂褶皱顶部显示初始缩放。在由这些褶皱形成的随机分布的微孔深处也发现了特征尺寸在 1 到 6 nm 之间的鳞片，这暗示了 CaCO ₃的异质结晶。因此，旨在限制 PA 层复杂折叠的膜可以显示出更大的抗水垢性。通过 TEM-K-means 改进的 PA 层可视化和由此产生的见解可广泛用于设计新型防垢膜和评估膜清洁操作的功效。