Probing Pore Wetting in Membrane Distillation Using Impedance: Early Detection and Mechanism of Surfactant-Induced Wetting
Probing Pore Wetting in Membrane Distillation Using Impedance: Early Detection and Mechanism of Surfactant-Induced Wetting
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DOI：
10.1021/acs.estlett.7b00372
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发表时间：
2017-11-01
影响因子：
10.9
通讯作者：
Lin, Shihong
中科院分区：
文献类型：
--
作者：
Chen, Yuanmiaoliang;Wang, Zhangxin;Lin, Shihong
孔润湿是膜蒸馏所特有的重要失效机制。现有的基于馏出物电导率的润湿检测方法仅在膜在完全通过孔隙的情况下失效时才有效。在这项研究中，我们开发了一种新颖而简单的方法，基于跨膜阻抗的测量，用于监测膜孔润湿的动态，并能够早期发现即将发生的基于润湿的膜失效。利用Triton X-100在直接接触MD实验中诱导孔隙润湿，我们证明了在馏分油电导率发生任何变化之前，单频阻抗对部分孔隙润湿的快速响应。为了阐明表面活性剂诱导孔隙润湿的机理，我们还进行了一个MD实验，使用有和不含表面活性剂的交替进料溶液。我们的实验结果表明，表面活性剂诱导的孔润湿是通过水气界面的渐进式运动发生的，表面活性剂在膜孔表面的吸附在控制渐进式润湿动力学中起重要作用。
Pore wetting is an important failure mechanism unique to membrane distillation (MD). The existing approach of wetting detection based on distillate conductivity works only when a membrane has failed in the presence of fully wicked-through pores. In this study, we develop a novel and simple method, based on measurement of cross-membrane impedance, for monitoring the dynamics of membrane pore wetting and enabling early detection of imminent wetting-based membrane failure. Using Triton X-100 to induce pore wetting in direct contact MD experiments, we demonstrated the rapid response of single-frequency impedance to partial pore wetting long before any change in distillate conductivity was observed. We also conducted an MD experiment using alternating feed solutions with and without surfactants to elucidate the mechanism of surfactant-induced pore wetting. Our experimental observations suggest that surfactant-induced pore wetting occurred via progressive movement of the water air interface and that adsorption of surfactants to the membrane pore surface plays an important role in controlling the kinetics of progressive wetting.