Forward osmosis membrane performance during simulated wastewater reclamation: Fouling mechanisms and fouling layer properties
Forward osmosis membrane performance during simulated wastewater reclamation: Fouling mechanisms and fouling layer properties
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DOI：
10.1016/j.jwpe.2018.03.007
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发表时间：
2018-06-01
影响因子：
7
通讯作者：
Verliefde, Arne R. D.
中科院分区：
文献类型：
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作者：
Motsa, Machawe M.;Mamba, Bhekie B.;Verliefde, Arne R. D.
采用薄膜复合膜（TFC）研究了以海藻酸盐、牛血清白蛋白、腐植酸和辛酸为代表的废水出水有机物（EfOM）组分的污染特性。这些模型污染物分别代表碳水化合物、蛋白质、腐殖质和脂肪酸。通过对含有模型污染物混合物的进料溶液进行一系列污染试验，确定了污染物之间的相互作用及其对膜通量损失的影响。结果表明，在我们的实验条件下，腐植酸（HA）和辛酸（OA）在短期内对污水处理过程中的渗透通量损失没有显著影响。然而，海藻酸盐和牛血清白蛋白（BSA）及其混合物通过海藻酸钙络合导致膜表面形成抗性凝胶层，造成显著的总通量损失。蛋白质污染主要是聚酰胺膜表面的多层吸附。海藻酸盐与BSA混合后，渗透通量进一步下降，比单独使用任何一种污染物的渗透通量下降幅度更大，表明两种污染物之间存在协同作用。碳水化合物和蛋白质之间存在良好的相互作用，促进了沉积在膜表面的杂化聚集体的形成，并增加了通量损失。在牛血清白蛋白和海藻酸盐混合物中添加腐植酸进一步加重了膜污染。在污水回收过程中，多糖和蛋白质是最主要的污染物。有机污染物之间的相互作用程度对污染层结构及其在渗透通量损失中的作用有影响。
A thin-film composite (TFC) FO membrane was used to study the fouling characteristics of effluent organic matter (EfOM) fractions in treated wastewater effluent represented by alginate, bovine serum albumin, humic acid and octanoic acid. These model foulants were chosen to represent carbohydrates, proteins, humic substances and fatty acids. Inter foulant interactions and their influence on membrane flux loss was established by running series of fouling tests with feed solutions containing mixtures of model foulants. The obtained results demonstrated that under our experimental conditions humic acid (HA) and octanoic acid (OA) had no significant role on permeate flux loss during wastewater treatment over short periods. However, alginate and bovine serum albumin (BSA) and their mixtures caused significant total flux loss, through alginate-calcium complexation that led to the formation of a resistant gel layer on the membrane surface. Protein fouling was mainly attributed to multiple layer adsorption onto the polyamide membrane surface. Mixing alginate with BSA saw a further decline in permeate flux, worse than that caused individually by either of the foulants, and gives an indication of the synergistic effect between the two foulants. There were favourable inter-foulant interactions between the carbohydrates and the proteins that promoted the formation of hybrid aggregates that were deposited on the membrane surface and enhanced flux loss. The additional presence of humic acid to the mixture of BSA and alginate further aggravated membrane fouling. Polysaccharides and proteins were found to be the most dominant foulants during wastewater reclamation. The extent of interactions between the organic foulants had an effect on the fouling layer structure and its role in permeate flux loss.