Comparison of the Effects of Extracellular and Intracellular Organic Matter Extracted From Microcystis aeruginosa on Ultrafiltration Membrane Fouling: Dynamics and Mechanisms
Comparison of the Effects of Extracellular and Intracellular Organic Matter Extracted From Microcystis aeruginosa on Ultrafiltration Membrane Fouling: Dynamics and Mechanisms
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铜绿微囊藻胞外和胞内有机物提取对超滤膜污染影响的比较：动力学和机制
DOI：
10.1021/es5035365
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发表时间：
2014-12-16
影响因子：
11.4
通讯作者：
Yu, Shuili
中科院分区：
文献类型：
--
作者：
Li, Lei;Wang, Zimeng;Yu, Shuili
藻类有机物（AOM）包括胞内有机物（IOM）和胞外有机物（EOM），是处理藻污染水体的主要膜污染物。在本研究中，研究了EOM和IOM（溶解有机物浓度为8 mg/L）对聚醚砜超滤（UF）膜污染的影响。基于扩展的DerjaguinLandauVerweyOverbeek （XDLVO）理论，分析了膜孔几何形状和膜与污染物相互作用能的变化。数据（相对标准偏差在10%以内）表明，UF能分别保留57%和46%的IOM和EOM，而相应的膜通量在比过滤体积仅为3.75 mL/cm(2)时迅速下降到28%和33%。结垢模型表明，饼的形成是主要机理。其中，IOM污染物的内聚自由能（-59.08 mJ/m(2)）远高于EOM污染物（3.2 mJ/m(2)），导致膜表面形成致密的饼层。而疏水EOM的小分子则倾向于被吸附到膜孔中，导致孔径和膜通量显著减小。因此，当考虑上述两种机制时，EOM和IOM引起的总体结垢率是可比较的。
Algae organic matter (AOM), including intracellular organic matter (IOM) and extracellular organic matter (EOM), are major membrane foulants in the treatment of algae-polluted water. In this study, the effects of EOM and IOM (at dissolved organic concentrations of 8 mg/L) on the fouling of a poly(ether sulfone) ultrafiltration (UF) membrane were investigated using a dead-end down-flow UF unit. Changes in the membrane pore geometry and the interaction energy between the membrane and foulants were analyzed based on the extended DerjaguinLandauVerweyOverbeek (XDLVO) theory. The data (relative standard deviation within 10%) showed that UF was able to retain 57% and 46% of IOM and EOM respectively, while the corresponding membrane fluxes rapidly reduced to 28% and 33% of their respective initial values after a specific filtration volume of only 3.75 mL/cm(2). The fouling model implied that cake formation was the major mechanism. Specifically, IOM foulant had a much greater free energy of cohesion (-59.08 mJ/m(2)) than EOM foulant (3.2 mJ/m(2)), leading to the formation of a compacted cake layer on the membrane surface. In contrast, small molecules of hydrophobic EOM tended to be adsorbed into the membrane pores, leading to significant reduction of the pore size and membrane flux. Therefore, the overall fouling rates caused by EOM and IOM were comparable when both of the above-mentioned mechanisms were considered.