School of Space and Environment, Beihang University, Beijing 100191, PR China.
School of Space and Environment, Beihang University, Beijing 100191, PR China.
Water Res. 2018 Oct 15;143:38-46. doi: 10.1016/j.watres.2018.06.027. Epub 2018 Jun 14.
Membrane technology has been widely employed for seawater desalination, water and wastewater reclamation, while membrane fouling still remains as a major challenge. The polysaccharides in extracellular polymeric substances (EPS) have been recognized as an important foulant that causes serious membrane fouling, while the detailed structure of polysaccharides and the intermolecular interactions between them have not been adequately disclosed. In this study, two different polysaccharides and their mixtures were used to study the intermolecular cross-linking of polysaccharides as well as its effects on membrane fouling. Results demonstrated that the fouling propensities of distinct polysaccharides were completely different, which was attributed to the different intermolecular interactions lying in polysaccharides. The cross-linking among molecules of polysaccharide, regardless of the homogeneity, was found to form complex networks and determine the effective dimension of polysaccharides. Depending on the effective dimension of foulants, pore blocking and cake layer occurred subsequently during filtration processes. In light of this, it potentially gives new insights into the fouling behaviours by combining the structure-function knowledge of polysaccharides with their fouling propensity. In addition, transparent exopolymeric particles (TEP) measurement was found to provide an intuitionistic evaluation of the complex networks formed from polysaccharides, so that may act as a good indicator of fouling during membrane filtration.
膜技术已广泛应用于海水淡化、水和废水回收，但膜污染仍然是一个主要挑战。细胞外聚合物（EPS）中的多糖已被认为是导致严重膜污染的重要污染物，但多糖的详细结构及其分子间相互作用尚未得到充分揭示。在这项研究中，使用两种不同的多糖及其混合物来研究多糖的分子间交联及其对膜污染的影响。结果表明，不同多糖的污染倾向完全不同，这归因于多糖中存在不同的分子间相互作用。多糖分子之间的交联，无论其均一性如何，都会形成复杂的网络，并决定多糖的有效维度。根据污染物的有效维度，在过滤过程中随后会发生孔堵塞和滤饼层形成。因此，通过将多糖的结构-功能知识与其污染倾向相结合，为污染行为提供了新的见解。此外，还发现透明胞外聚合物（TEP）测量可以直观地评估多糖形成的复杂网络，因此可以作为膜过滤过程中污染的良好指标。
