Negative Pressure Membrane Distillation: A Novel Strategy for Wetting Mitigation
打印- 论文题目: Negative Pressure Membrane Distillation: A Novel Strategy for Wetting Mitigation
- 作者: Wang, Yidan; Chen, Yuanmiaoliang; Lin, Shihong; Wang, Zhangxin; He, Tao
- 刊名: ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS
- 出版年: 2022 文献号: 2328-8930
- 关键词:
Wang, Yidan; Chen, Yuanmiaoliang; Lin, Shihong; Wang, Zhangxin; He, Tao - 摘要:
As an emerging desalination technology for hypersaline wastewater treatment, membrane distillation (MD) faces a critical challenge of membrane wetting. The state-of-the-art wetting mitigation strategy in MD is to use novel membranes that are commercially unavailable and difficult to fabricate. This study proposes an operational mode, negative pressure MD (NPMD), as a novel wetting mitigation strategy in MD operations. Compared with conventional MD, NPMD can substantially enhance the wetting resistance of commercially available hydrophobic MD membranes. Specifically, in a conventional direct contact MD (DCMD) operation, a polyvinylidene fluoride (PVDF) membrane is easily wetted by a 0.1 mM sodium dodecyl sulfate (SDS) feed solution, while in NPMD, the PVDF membrane can remain unwetted with a 0.2 mM feed solution. By determining the liquid entry pressure (LEP) of the PVDF membrane using an impedance-based technique, the working mechanism of NPMD for wetting mitigation is illustrated, and such a mechanism is further confirmed by DCMD experiments using feed solutions containing ethanol. With a negative gauge pressure on the feed stream, the transmembrane hydraulic pressure becomes lower than the LEP of the PVDF membrane, thereby mitigating membrane wetting. As a simple yet effective wetting mitigation strategy, NPMD can be readily implemented in practice with commercially available hydrophobic membranes, showing vast potential to advance MD applications.
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