Meng Xianghao, Wang Fukuan, Meng Shujuan, Wang Rui, Mao Zhongyuan, Li Yue, Yu Meifeng, Wang Xuye, Zhao Qian, Yang Linyan
School of Space and Environment, Beihang University, Beijing 100191, China.
College of Mechanical Engineering, Guangxi University, Nanning 530004, China.
Membranes (Basel). 2021 Dec 18;11(12):990. doi: 10.3390/membranes11120990.
It is difficult to recognize specific fouling mechanisms due to the complexity of practical feed water, thus the current studies usually employ foulant surrogates to carry out research, such as alginate and xanthan gum. However, the representativeness of these surrogates is questionable. In this work, the classical surrogates (i.e., alginate and xanthan gum) were systematically studied, and results showed that they behaved differently during filtration. For the mixture of alginate and xanthan gum, both filtration behaviors and adsorption tests performed by quartz-crystal microbalance with dissipation monitoring (QCM-D) indicated that alginate plays a leading role in fouling development. Furthermore, by examining the filtration behaviors of extracellular polymeric substances (EPS) extracted from practical source water, it turns out that the gel layer formation is responsible for EPS fouling, and the properties of gel layer formed by EPS share more similarities with that formed from pectin instead of alginate. In addition, with the use of experimental data sets extracted from this study and our previous studies, a modeling method was established and tested by the support vector machine (SVM) to predict complex filtration behaviors. Results showed that the small differences of fouling mechanisms lying between alginate and pectin cannot be recognized by Hermia's models, and SVM can show a discrimination as high as 76.92%. As such, SVM may be a powerful tool to predict complex filtration behaviors.
由于实际给水的复杂性，很难识别具体的污垢形成机制，因此目前的研究通常使用污垢替代物来开展研究，如藻酸盐和黄原胶。然而，这些替代物的代表性值得怀疑。在这项工作中，对经典替代物（即藻酸盐和黄原胶）进行了系统研究，结果表明它们在过滤过程中的表现不同。对于藻酸盐和黄原胶的混合物，过滤行为以及通过带耗散监测的石英晶体微天平（QCM-D）进行的吸附测试均表明，藻酸盐在污垢形成过程中起主导作用。此外，通过研究从实际水源水中提取的胞外聚合物（EPS）的过滤行为发现，凝胶层的形成是EPS污垢形成的原因，并且由EPS形成的凝胶层的性质与由果胶而非藻酸盐形成的凝胶层的性质有更多相似之处。此外，利用本研究和我们之前研究中提取的实验数据集，建立了一种建模方法，并通过支持向量机（SVM）进行测试以预测复杂的过滤行为。结果表明，藻酸盐和果胶之间污垢形成机制的细微差异无法被赫米亚模型识别，而SVM的判别准确率高达76.92%。因此，SVM可能是预测复杂过滤行为的有力工具。
