School of Space and Environment, Beihang University, Beijing, 100191, PR China.
School of Space and Environment, Beihang University, Beijing, 100191, PR China.
Chemosphere. 2021 Apr;268:129364. doi: 10.1016/j.chemosphere.2020.129364. Epub 2020 Dec 18.
Polysaccharide foulant is known to play a crucial role in membrane fouling, however the detailed influential mechanisms and the pertinence to specific structure of polysaccharides, as well as intermolecular interactions among them with and without divalent cation are still indistinct. In this study, seven polysaccharides including agarose, sodium alginate, carrageenan, pectin, starch, sodium carboxymethylcellulose (CMC) and xanthan gum, with different chain and molecular structures, were used as model foulants to investigate the role of structural and functional features of polysaccharides in membrane fouling. Two Hermia's models (classical and mass-transfer models) as well as the resistance-in-series model were used to analyze the fouling mechanism. Results show that the spatial configuration of foulant molecule is significant in membrane fouling which actually controls the resistance of gel layer formed on membrane. Polysaccharides with different properties show distinct fouling mechanisms which are in accordance with the four models described by Hermia respectively. Cations may change the interaction of polysaccharide foulant which further leads to the structural change of the gel layer. It turns out that mass-transfer model is more suitable for interpreting of crossflow filtration data. So far, little has been known about the effects of molecule structure of polysaccharides on membrane fouling. In this paper, we provide a basic database for polysaccharide fouling which will work as a theoretical basis for finding more effective measures to prevent and control membrane fouling.
多糖污染物在膜污染中起着至关重要的作用，然而多糖的详细影响机制及其与特定结构的相关性，以及它们之间在有无二价阳离子存在时的分子间相互作用仍然不清楚。在这项研究中，使用了七种具有不同链和分子结构的多糖作为模型污染物，包括琼脂糖、海藻酸钠、卡拉胶、果胶、淀粉、羧甲基纤维素钠 (CMC) 和黄原胶，以研究多糖的结构和功能特性在膜污染中的作用。使用了 Hermia 的两种模型（经典模型和传质模型）以及串联阻力模型来分析污染机制。结果表明，污染物分子的空间构象在膜污染中非常重要，实际上控制了在膜上形成的凝胶层的阻力。具有不同性质的多糖表现出不同的污染机制，分别符合 Hermia 描述的四个模型。阳离子可能改变多糖污染物的相互作用，从而导致凝胶层的结构发生变化。事实证明，传质模型更适合解释错流过滤数据。到目前为止，人们对多糖分子结构对膜污染的影响知之甚少。在本文中，我们提供了一个多糖污染的基础数据库，这将为寻找更有效的防止和控制膜污染的措施提供理论依据。
