Membranes used for desalination still face challenges during operation. One of these challenges is the buildup of salt ions at the membrane surface. This is known as concentration polarization, and it has a negative effect on membrane water permeance and salt rejection. In an attempt to decrease concentration polarization, a line-and-groove nanopattern was applied to a nanofiltration (NF) membrane. Aqueous sodium sulfate (Na2SO4) solutions were used to test the rejection and permeance of both pristine and patterned membranes. It was found that the nanopatterns did not reduce but increased the concentration polarization at the membrane surface. Based on these studies, different pattern shapes and sizes should be investigated to gain a fundamental understanding of the influence of pattern size and shape on concentration polarization.
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Printing ultrathin graphene oxide nanofiltration membranes for water purification
We demonstrated for the first time that inkjet printing can be a low-cost, easy, fast, and scalable method for depositing ultrathin (7.5–60 nm) uniform graphene oxide (GO) nanofiltration membranes on polymeric supports for highly effective water purification. A large area (15 × 15 cm 2 ) GO nanofiltration membrane was printed successfully on a modified polyacrylonitrile (M-PAN) support. Water permeance and rejection of small organic molecules (<1 nm, charged and uncharged) of printed GO membranes can be adjusted by controlling the GO “ink” concentration and/or printing time. Compared with commercial polymeric nanofiltration membranes, printed GO membranes, after optimization, showed approximately one order of magnitude higher water permeance and much higher rejection (>95%) of small organic molecules. Printed GO membranes also showed excellent performance in removing pharmaceutical contaminants, with ∼95% rejection and <10% water permeance decline over extended-period permeation testing. We believe that inkjet printing could be an effective method for preparing ultrathin GO membranes for effective water nanofiltration purification.
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- Award ID(s):
- 1451887
- PAR ID:
- 10140637
- Date Published:
- Journal Name:
- J. Mater. Chem. A
- Volume:
- 5
- Issue:
- 39
- ISSN:
- 2050-7488
- Page Range / eLocation ID:
- 20860 to 20866
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/c7ta06307e
