Porous hydrophobic-hydrophilic composite membranes for direct contact membrane distillation

Document Type

Article

Publication Date

12-1-2019

Abstract

Direct contact membrane distillation (DCMD) for desalination is attractive for high salt concentrations if low-cost steam/waste heat is available and waste brine disposal cost for inland desalination is factored in. A number of innovations have taken place in DCMD in terms of the structure of the porous hydrophobic membrane. Composite membranes are of increasing interest. Composite membrane structures of great interest include a thin hydrophobic porous layer over a porous hydrophilic layer of polyvinylidene fluoride (PVDF) or a thin porous hydrophobic layer over a more conventional hydrophobic porous membrane. These membranes can be in the form of an integral composite or a stacked composite or a laminated composite. A facile method of fabricating such integral composite membranes is plasma polymerization under vacuum. A class of such membranes yielding quite high water vapor fluxes have been characterized using a variety of characterization techniques: Contact angle, liquid entry pressure (LEP), bubble-point pressure, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM). Stacked composites of a hydrophobic ePTFE membrane over a hydrophilic PVDF membrane or a hydrophobic PVDF membrane over another hydrophobic PVDF membrane were also studied. Novel conditions created lead to very high water vapor fluxes compared to those from conventional hydrophobic membranes supported on a mesh support.

Identifier

85073703766 (Scopus)

Publication Title

Journal of Membrane Science

External Full Text Location

https://doi.org/10.1016/j.memsci.2019.117225

e-ISSN

18733123

ISSN

03767388

Volume

591

Grant

1822130

Fund Ref

National Science Foundation

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