Significance of surface excess concentration in the kinetics of surfactant-induced pore wetting in membrane distillation
Significance of surface excess concentration in the kinetics of surfactant-induced pore wetting in membrane distillation
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DOI：
10.1016/j.desal.2018.10.024
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发表时间：
2019-01
期刊：
影响因子：
9.9
通讯作者：
Zhangxin Wang;Yuanmiaoliang Chen;Feiyang Zhang;Shihong Lin
中科院分区：
文献类型：
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作者：
Zhangxin Wang;Yuanmiaoliang Chen;Feiyang Zhang;Shihong Lin
由于两亲性分子润湿孔隙而导致的膜蒸馏（MD）失败最近引起了越来越多的关注，因为这是MD适用于处理非常规给水需要克服的关键挑战。最近使用含有表面活性剂的进料溶液进行的 MD 研究阐明了润湿的基本机制，并产生了缓解润湿的实用解决方案。然而，目前尚不清楚表面活性剂种类对孔隙润湿动力学的影响。基于最近开发的表面活性剂引起的MD孔隙润湿动力学模型，我们假设表面活性剂的表面过量浓度是影响孔隙润湿动力学的最重要的表面活性剂特性。在这项研究中，我们使用七种不同类型的表面活性剂进行了受控MD润湿实验，并测量了它们各自的突破时间作为润湿动力学的定量指标。我们的实验表明，除了一种测试的表面活性剂外，大多数表面活性剂的表面过量浓度和突破时间之间存在良好的线性相关性。当同时考虑表面过量浓度和扩散系数时，对于所有测试的表面活性剂，模型模拟的突破时间与实验测量结果非常吻合。
Failure of membrane distillation (MD) due to pore wetting by amphiphilic molecules has recently received growing interests because it is a critical challenge to overcome for MD to be applicable for treating unconventional feed water. Recent MD studies using feed solutions containing surfactants have elucidated fundamental mechanism of wetting and generated practical solutions for wetting mitigation. However, what remains unclear is the impact of surfactant species on pore wetting kinetics. Based on a recently developed kinetic model for surfactant-induced pore wetting in MD, we hypothesize that the surface excess concentration of a surfactant is the most important surfactant property in affecting the pore wetting kinetics. In this study, we performed controlled MD wetting experiments using seven different types of surfactants and measured their respective breakthrough time as a quantitative metric for wetting kinetics. Our experiments reveal a good linear correlation between the surface excess concentration and breakthrough time for most but one tested surfactant. When surface excess concentration and diffusion coefficient are both considered, the model-simulated breakthrough time matches the experimentally measurement remarkably well for all tested surfactants.