Bio-inspired gas-entrapping membranes (GEMs) derived from common water-wet materials for green desalination
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KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Environmental Science and Engineering
Environmental Science and Engineering Program
King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Biological and Environmental Science and Engineering (BESE) Division, Thuwal, 23955-6900, Saudi Arabia
Water Desalination & Reuse Center
Water Desalination and Reuse Research Center (WDRC)
KAUST Grant NumberBAS/1/1070-01-01
Online Publication Date2019-06-16
Print Publication Date2019-10
Permanent link to this recordhttp://hdl.handle.net/10754/656244
MetadataShow full item record
AbstractWidespread stress on global water supplies compels the need for low-cost and sustainable desalination processes. In this regard, desalination through membrane distillation (MD) can harness waste-grade heat or renewable energy. So far, the membranes for MD have been exclusively derived from intrinsically water-repellant materials - mostly perfluorocarbons. However, perfluorocarbons are limiting in terms of operational conditions, and they also introduce economic and environmental concerns. The development of perfluorocarbon-free MD membranes would likely address those challenges. Here, we report on the proof-of-concept for biomimetic gas-entrapping membranes (GEMs) for MD derived from silica and poly(methyl methacrylate) (PMMA) that are water-wet materials. We drew inspiration for our GEM design from the cuticles of springtails and hairs of Halobates germanus, both of which exhibit mushroom-shaped (or reentrant) features. Accordingly, our GEMs comprise arrays of microscale cylindrical pores with reentrant inlets and outlets that can robustly entrap air on submersion in water. Our PMMA-GEMs yielded a vapor flux of J ≈ 1 L-m−2-h−1 while separating a solution of ∼0.6 M NaCl at 333 K from deionized water at 288 K under a cross-flow configuration. To our knowledge, this is the first-ever demonstration of MD membranes derived from intrinsically water-wet materials, and these findings suggest that the rational design of membranes towards greener and cheaper desalination processes is possible.
SponsorsThe authors thank KAUST Baseline Research Funding (BAS/1/1070-01-01). We thank Mr. Ulrich Buttner and Mr. Ahad A. Sayed from the KAUST Core Labs for their assistance with microfabrication. We thank Mr. Adair Gallo Junior for assistance with the MD experiments; Dr. Dina Garatly for assistance in preparing Fig. 3 and Figure S2; Dr. Eddy Domingues (Universidade de Aveiro, Portugal) for providing recipes for the dry etching of silica and silicon layers. The authors also thank Dr. Virginia Unkefer (KAUST) for assistance in editing the manuscript. We also thank Prof. Wei Song Hwang (National University of Singapore) and Prof. Lanna Cheng (Scripps Institution of Oceanography) for kindly providing us with specimens of springtails whose images we have presented in Fig. 1A–E. The co-authors thank Mr. Ivan Gromicho, Scientific Illustrator at KAUST, for preparing Fig. 4.
JournalJournal of Membrane Science
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