TY - JOUR
T1 - Fabrication of Janus Membranes for Desalination of Oil-Contaminated Saline Water
AU - Mohammadi Ghaleni, Mahdi
AU - Al Balushi, Abdullah
AU - Kaviani, Shayan
AU - Tavakoli, Elham
AU - Bavarian, Mona
AU - Nejati, Siamak
N1 - Funding Information:
The authors would like to acknowledge the financial support from the Bureau of Reclamation, U.S. Department of Interior, through DWPR Agreement R17AC00139. The research was performed, in part, in the Nebraska Nanoscale Facility, National Nanotechnology Coordinated Infrastructure and the Nebraska Center for Materials and Nanoscience, which are supported by the National Science Foundation under award ECCS 1542182, and the Nebraska Research Initiative.
PY - 2018/12/26
Y1 - 2018/12/26
N2 - Desalination of oil-contaminated saline water using membrane distillation requires hydrophobic membranes with underwater superoleophobic surfaces. For designing such membranes, the chemistry and morphology of the interfacial domains in contact with the contaminated water need to be adjusted such that a stable water layer, adhering to the surface, prevents oil droplets from wetting the membrane. In this article, we present an approach that relies on the controlled functionalization of the surface of polyvinylidene fluoride (PVDF) membranes; we adjust the surface topography of the membranes and introduce chemical heterogeneity to them. We show that the morphology of the PVDF surface can be altered by adjusting the composition of the nonsolvent bath used for the phase inversion process. Also, we render the surface of the membranes hydrophilic by using an alkaline chemical bath solution. The membrane morphology and effectiveness of our chemical treatment were confirmed by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Fourier-transformed infrared spectroscopy (FTIR), and zeta potential measurements. A stable underwater contact angle, higher than 150°, was observed for both canola oil (P ≈ 0.913 g cm -3 , γ ≈ 31.5 mN m -1 ) and hexane (P ≈ 0.655 g cm -3 , γ ≈ 18 mN m -1 ). We evaluated the performance of both pristine and functionalized membranes in a laboratory-scale direct contact membrane distillation (DCMD) setup and desalinated a saline solution contaminated with 500 ppm canola oil. Our results show that oil does not wet the functionalized membrane during the desalination process. The average permeate flux and salt rejection values for the functionalized membranes were 45 ± 5 Lm -2 h -1 (T feed = 70 °C, T distillate = 20 °C) and 99.99%, respectively.
AB - Desalination of oil-contaminated saline water using membrane distillation requires hydrophobic membranes with underwater superoleophobic surfaces. For designing such membranes, the chemistry and morphology of the interfacial domains in contact with the contaminated water need to be adjusted such that a stable water layer, adhering to the surface, prevents oil droplets from wetting the membrane. In this article, we present an approach that relies on the controlled functionalization of the surface of polyvinylidene fluoride (PVDF) membranes; we adjust the surface topography of the membranes and introduce chemical heterogeneity to them. We show that the morphology of the PVDF surface can be altered by adjusting the composition of the nonsolvent bath used for the phase inversion process. Also, we render the surface of the membranes hydrophilic by using an alkaline chemical bath solution. The membrane morphology and effectiveness of our chemical treatment were confirmed by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Fourier-transformed infrared spectroscopy (FTIR), and zeta potential measurements. A stable underwater contact angle, higher than 150°, was observed for both canola oil (P ≈ 0.913 g cm -3 , γ ≈ 31.5 mN m -1 ) and hexane (P ≈ 0.655 g cm -3 , γ ≈ 18 mN m -1 ). We evaluated the performance of both pristine and functionalized membranes in a laboratory-scale direct contact membrane distillation (DCMD) setup and desalinated a saline solution contaminated with 500 ppm canola oil. Our results show that oil does not wet the functionalized membrane during the desalination process. The average permeate flux and salt rejection values for the functionalized membranes were 45 ± 5 Lm -2 h -1 (T feed = 70 °C, T distillate = 20 °C) and 99.99%, respectively.
KW - chemical modification
KW - membrane distillation
KW - oil-water separation
KW - surface functionalization
KW - underwater oleophobic
KW - water desalination
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U2 - 10.1021/acsami.8b16621
DO - 10.1021/acsami.8b16621
M3 - Article
C2 - 30511847
AN - SCOPUS:85058656046
VL - 10
SP - 44871
EP - 44879
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 51
ER -