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1. Novel Janus Membrane for Membrane Distillation with Simultaneous Fouling and Wetting Resistance

   https://doi.org/10.1021/acs.est.7b02848  

   Huang, Yu-Xi ; Wang, Zhangxin ; Jin, Jian ; Lin, Shihong ( November 2017 , Environmental Science & Technology)
2. Elucidating the Trade-off between Membrane Wetting Resistance and Water Vapor Flux in Membrane Distillation

   https://doi.org/10.1021/acs.est.0c02547  

   Li, Chenxi ; Li, Xuesong ; Du, Xuewei ; Zhang, Ying ; Wang, Wei ; Tong, Tiezheng ; Kota, Arun Kumar ; Lee, Jongho ( August 2020 , Environmental Science & Technology)

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3. Hydrophobicity versus pore size: polymer coatings to improve membrane wetting resistance for membrane distillation

   https://doi.org/10.1021/acsapm.9b01133  

   McGaughey, Allyson L. ; Karandikar, Prathamesh ; Gupta, Malancha ; Childress, Amy E. ( February 2020 , ACS applied polymer materials)

   null (Ed.)

   Initiated chemical vapor deposition (iCVD) was used to coat two porous substrates (i.e., hydrophilic cellulose acetate (CA) and hydrophobic polytetrafluoroethylene (PTFE)) with a crosslinked fluoropolymer to improve membrane wetting resistance. The coated CA membrane was superhydrophobic and symmetric. The coated PTFE membrane was hydrophobic and asymmetric, with smaller pore size and lower porosity on the top surface than on the bottom surface. Membrane performance was tested in membrane distillation experiments with (1) a high-salinity feed solution and (2) a surfactant-containing feed solution. In both cases, the coated membranes had higher wetting resistance than the uncoated membranes. Notably, wetting resistances were better predicted by LEP distributions than by minimum LEP values. When LEP distributions were skewed towards high LEP values (i.e., when small pores with high LEP were greater in number), significant (measurable) salt passage did not occur. For the high-salinity feed solution, the coated PTFE membrane had greater wetting resistance than the coated CA membrane; thus, reduced surface pore size/porosity (which may reduce intrapore scaling) was more effective than increased surface hydrophobicity (which may reduce surface nucleation) in preventing scaling-induced wetting. Reduced pore size/porosity was equally as effective as increased hydrophobicity in resisting surfactant-induced wetting. However, reduced porosity can negatively impact water flux; this represents a permeability/wetting resistance tradeoff in membrane distillation – especially for high-salinity applications. Membrane and/or membrane coating properties must be optimized to overcome this permeability/wetting resistance tradeoff and make MD viable for the treatment of challenging streams. Then, increasing hydrophobicity may not be necessary to impart high wetting resistance to porous membranes. These results are important for future membrane design, especially as manufacturers seek to replace perfluorinated materials with environmentally friendly alternatives. 

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4. Probing Pore Wetting in Membrane Distillation Using Impedance: Early Detection and Mechanism of Surfactant-Induced Wetting

   https://doi.org/10.1021/acs.estlett.7b00372  

   Chen, Yuanmiaoliang ; Wang, Zhangxin ; Jennings, G. Kane ; Lin, Shihong ( November 2017 , Environmental Science & Technology Letters)
5. Resistance and change in a High Arctic ecosystem, NW Greenland: Differential sensitivity of ecosystem metrics to 15 years of experimental warming and wetting

   https://doi.org/10.1111/gcb.16027  

   Jespersen, Robert Gus ; Leffler, Alan Joshua ; Väisänen, Maria ; Welker, Jeffrey M. ( December 2021 , Global Change Biology)

   Dramatic increases in air temperature and precipitation are occurring in the High Arctic (>70°N), yet few studies have characterized the long‐term responses of High Arctic ecosystems to the interactive effects of experimental warming and increased rain. Beginning in 2003, we applied a factorial summer warming and wetting experiment to a polar semidesert in northwest Greenland. In summer 2018, we assessed several metrics of ecosystem structure and function, including plant cover, greenness, ecosystem CO₂exchange, aboveground (leaf, stem) and belowground (litter, root, soil) carbon (C) and nitrogen (N) concentrations (%) and pools, as well as leaf and soil stable isotopes (δ¹³C and δ¹⁵N). Wetting induced the most pronounced changes in ecosystem structure, accelerating the expansion ofSalix arcticacover by 370% and increasing aboveground C, N, and biomass pools by 94%–101% and root C, N, and biomass pools by 60%–122%, increases which coincided with enhanced net ecosystem CO₂uptake. Further, wetting combined with warming enhanced plot‐level greenness, whereas in isolation neither wetting nor warming had an effect. At the plant level, the effects of warming and wetting differed among species and included warming‐linked decreases in leaf N and δ¹⁵N inS. arctica, whereas leaf N and δ¹⁵N inDryas integrifoliadid not respond to the climate treatments. Finally, neither plant‐ nor plot‐level C and N allocation patterns nor soil C, N, δ¹³C, or δ¹⁵N concentrations changed in response to our manipulations, indicating that these ecosystem metrics may resist climate change, even in the longer term. In sum, our results highlight the importance of summer precipitation in regulating ecosystem structure and function in arid parts of the High Arctic, but they do not completely refute previous findings of resistance in some High Arctic ecosystem properties to climate change.

    

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