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Development of robust and superhydrophobic membranes to mitigate membrane scaling and fouling in membrane distillation

Membrane distillation (MD) has attracted increasing attention for seawater and brackish water desalination, wastewater treatment, and concentration of juices and pharmaceutical solutions due to its feasibility of using low-grade energy and achieving high solute rejection. However, the successful imp...

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Bibliographic Details
Published in:Journal of membrane science 2020-03, Vol.601, p.117962, Article 117962
Main Authors: Liao, Yuan, Zheng, Guangtai, Huang, Jinhui Jeanne, Tian, Miao, Wang, Rong
Format: Article
Language:English
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Summary:Membrane distillation (MD) has attracted increasing attention for seawater and brackish water desalination, wastewater treatment, and concentration of juices and pharmaceutical solutions due to its feasibility of using low-grade energy and achieving high solute rejection. However, the successful implementation of MD technology is still impeded by membrane wetting resulted from membrane scaling by inorganic crystals and membrane fouling by organic matters in the feed solutions, especially when dealing with challenging wastewaters. Herein, this study describes a novel strategy to develop a robust and superhydrophobic membrane via electrospinning followed by electrospray to enhance membrane anti-wetting properties caused by scaling and fouling. The robust superhydrophobic membrane PDMS-3 comprised a superhydrophobic surface layer fabricated by electrospraying a PVDF/PDMS/silica fume blended solution and an electrospun nanofibrous PVDF support. The newly developed membrane PDMS-3 not only exhibited an outstanding superhydrophobicity with a water contact angle of 170⁰ ± 1⁰, but also showed a unique anti-abrasive feature, which still possessed a slippery superhydrophobic property after 40 abrasion cycles. Moreover, the DCMD tests revealed that this rigid superhydrophobic surface rendered PDMS-3 with the best anti-scaling and anti-fouling properties compared to the nanofibrous and commercial PVDF membranes. It could achieve a superior MD flux of 28 kg m−2 h−1and a stable salt rejection above 99.99% during a continuous 160-h DCMD operation when the feed and permeation solutions were 3.5 wt% NaCl solution at 333K and distillate water at 293 K, respectively. These results underline the importance of anti-abrasive superhydrophobic membrane development to deal with wastewaters containing diverse inorganic and organic matters via MD. •The robust and superhydrophobic composite membranes were fabricated by electrospinning and electrospray.•The abrasive resistance of as-developed superhydrophobic membranes were examined.•PDMS-3 with the highest silica content exhibits the best anti-abrasive property.•Compared to nanofibrous PVDF membrane, PDMS-3 exhibits better anti-scaling and anti-fouling properties.•The surface property of PDMS-3 is significant in determining its long-term stability in MD.
ISSN:0376-7388
1873-3123
DOI:10.1016/j.memsci.2020.117962