Laboratoire de Rhéologie, Université Joseph Fourier - Grenoble I, Grenoble - Institut National Polytechnique, CNRS, UMR 5520, BP 53, F-38041 Grenoble Cedex 9, France.
Langmuir. 2012 Jan 17;28(2):1083-94. doi: 10.1021/la201492z. Epub 2011 Dec 27.
The structural organization inside the concentration polarization layer during cross-flow membrane separation process of Laponite colloidal dispersions has been characterized for the first time by in situ time-resolved small-angle X-ray scattering (SAXS). Thanks to the development of new "SAXS cross-flow filtration cells", concentration profiles have been measured as a function of the distance z from the membrane surface with 50 μm accuracy and linked to the permeation flux, cross-flow, and transmembrane pressure registered simultaneously. Different rheological behaviors (thixotropic gel with a yield stress or shear thinning sol) have been explored by controlling the mutual interactions between the particles as a result on the addition of peptizer. The structural reversibility of the concentration polarization layer has been demonstrated being in agreement with permeation flux measurements. These observations were related to structure of the dispersions under flow and their osmotic pressure.
首次通过原位时间分辨小角 X 射线散射（SAXS）对 Laponite 胶体分散体错流膜分离过程中浓差极化层的内部结构组织进行了表征。得益于新型“SAXS 错流过滤池”的发展，已经可以精确地测量距膜表面的距离 z 处的浓度分布，并将其与同时记录的渗透通量、错流和跨膜压力相关联。通过控制颗粒间的相互作用，添加分散剂可探索不同的流变行为（具有屈服应力的触变凝胶或剪切稀化溶胶）。浓差极化层的结构可逆性与渗透通量测量结果一致。这些观察结果与流动状态下的分散体结构及其渗透压有关。
