Janus Membrane with a Dense Hydrophilic Surface Layer for Robust Fouling and Wetting Resistance in Membrane Distillation: New Insights into Wetting Resistance
Janus Membrane with a Dense Hydrophilic Surface Layer for Robust Fouling and Wetting Resistance in Membrane Distillation: New Insights into Wetting Resistance
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DOI：
10.1021/acs.est.1c04443
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发表时间：
2021-10-01
影响因子：
11.4
通讯作者：
Lin, Shihong
中科院分区：
文献类型：
--
作者：
Feng, Dejun;Chen, Yuanmiaoliang;Lin, Shihong
尽管膜蒸馏(MD)被认为是处理高含盐废水的一种很有前途的技术，但它的实际应用面临着两个突出的挑战：膜的润湿和污染。在这里，我们报道了一种简单且可扩展的方法来制备Janus MD膜，该膜包括致密的聚乙烯醇(PVA)表层和疏水的聚偏氟乙烯(PVDF)膜基板。通过使用含有十二烷基硫酸钠(SDS)表面活性剂或/和矿物油的饲料，在直接接触MD实验中测试Janus膜，我们证明了致密的Janus膜可以同时抵抗湿润和污染。这种方法代表了迄今为止制备同时具有润湿和污染阻力的MD膜的最简单的方法。重要的是，我们还通过测量突破压力和表面活性物质的渗透(通过PVA层)揭示了润湿阻力的机理，发现致密的亲水层所赋予的润湿阻力归因于毛细压力。这一新的见解将潜在地改变制造耐湿膜的范例，并使MD和其他膜接触器工艺面临孔湿或/和膜污染挑战的强大应用成为可能。
Although membrane distillation (MD) has been identified as a promising technology to treat hypersaline wastewaters, its practical applications face two prominent challenges: membrane wetting and fouling. Herein, we report a facile and scalable approach for fabricating a Janus MD membrane comprising a dense polyvinyl alcohol (PVA) surface layer and a hydrophobic polyvinylidene fluoride (PVDF) membrane substrate. By testing the Janus membrane in direct contact MD experiments using feeds containing a sodium dodecyl sulfate (SDS) surfactant or/and mineral oil, we demonstrated that the dense Janus membrane can simultaneously resist wetting and fouling. This method represents the simplest approach to date for fabricating MD membranes with simultaneous wetting and fouling resistance. Importantly, we also unveil the mechanism of wetting resistance by measuring the breakthrough pressure and surfactant permeation (through the PVA layer) and found that wetting resistance imparted by a dense hydrophilic layer is attributable to capillary pressure. This new insight will potentially change the paradigm of fabricating wetting-resistant membranes and enable robust applications of MD and other membrane contactor processes facing challenges of pore wetting or/and membrane fouling.