Abstract Chemical characterization of scaling and removal processes was performed in real time via Raman spectroscopy in a bench-scale reverse osmosis (RO) system. A custom RO cross-flow cell was integrated with a Raman microscope objective, allowing for analysis of localized membrane scaling and scale removal. Permeate flux was also measured to provide a real-time metric for comparison. A commercial flat sheet, thin-film composite reverse osmosis (TFC RO) membrane was scaled using a calcium sulfate (CaSO4·H2O) feed solution. Upon CaSO4 scale detection, the feed was switched to DI water, which served as a cleaning agent to remove the CaSO4 scale from the membrane. In addition to the real-time local (Raman) and global (permeate flux) measurements, membrane samples were characterized post-mortem using Raman spectroscopy, gravimetric analysis and scanning electron microscopy to provide important scaling and scale removal metrics. Results from real-time measurements indicated that changes in Raman intensity were a more sensitive indicator of local scale removal than changes in permeate flux, a standard cleaning performance metric; these findings were corroborated by the post-mortem analyses. Overall, the membrane cleaning experiments showed that Raman spectroscopy provided crucial real-time chemical composition and spatial distribution information, which can inform more effective antiscaling and cleaning strategies.

中文翻译：

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使用拉曼光谱实时监测反渗透海水淡化膜中硫酸钙垢的去除情况

摘要 通过拉曼光谱在实验室规模的反渗透 (RO) 系统中实时进行结垢和去除过程的化学表征。一个定制的 RO 交叉流动池与拉曼显微镜物镜集成在一起，允许分析局部膜结垢和水垢去除。还测量了渗透通量以提供用于比较的实时度量。使用硫酸钙 (CaSO4·H2O) 进料溶液对商用平板薄膜复合反渗透 (TFC RO) 膜进行缩放。在检测到 CaSO4 水垢后，将进料切换为去离子水，作为清洁剂从膜上去除 CaSO4 水垢。除了实时局部（拉曼）和全局（渗透通量）测量外，还使用拉曼光谱对膜样品进行验尸表征，重量分析和扫描电子显微镜，以提供重要的结垢和水垢去除指标。实时测量的结果表明，拉曼强度的变化是局部水垢去除的一个更敏感的指标，而不是渗透通量的变化，这是一种标准的清洁性能指标；尸检分析证实了这些发现。总体而言，膜清洁实验表明，拉曼光谱提供了关键的实时化学成分和空间分布信息，可以为更有效的防垢和清洁策略提供信息。标准的清洁性能指标；尸检分析证实了这些发现。总体而言，膜清洁实验表明，拉曼光谱提供了关键的实时化学成分和空间分布信息，可以为更有效的防垢和清洁策略提供信息。标准的清洁性能指标；尸检分析证实了这些发现。总体而言，膜清洁实验表明，拉曼光谱提供了关键的实时化学成分和空间分布信息，可以为更有效的防垢和清洁策略提供信息。