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Produced water (PW) generated from oil and gas operations poses a significant environmental challenge due to its high salinity and complex organic–inorganic composition. This study evaluates forward osmosis (FO) as an energy-efficient approach for PW treatment by comparing a commercial cellulose triacetate (CTA) membrane and a fabricated electrospun nanofibrous membrane, both modified with a zwitterionic sulfobetaine methacrylate/polydopamine (SBMA/PDA) coating. Fourier Transform Infrared Spectroscopy (FTIR) spectra verified the successful incorporation of SBMA and PDA through the appearance of characteristic sulfonate, quaternary ammonium, and catechol/amine-related vibrations. Scanning electron microscopy (SEM) imaging revealed the intrinsic dense surface of the CTA membrane and the highly porous nanofibrous architecture of the electrospun membrane, with both materials showing uniform coating coverage after modification. Complementary analyses supported these observations: X-ray Photoelectron Spectroscopy (XPS) confirmed the presence of nitrogen, sulfur, and chlorine containing functionalities associated with the zwitterionic layer; Thermogravimetric Analysis (TGA) demonstrated that surface modification did not compromise the thermal stability of either membrane; and contact-angle measurements showed substantial increases in surface hydrophilicity following modification. Gas chromatography–mass spectrometry (GC–MS) analysis of the Permian Basin PW revealed a chemically complex mixture dominated by light hydrocarbons, alkylated aromatics, and heavy semi-volatile organic compounds. FO experiments using hypersaline PW demonstrated that the fabricated membrane consistently outperformed the commercial membrane under both MgCl2 and Na3PO4 draw conditions, achieving up to ~40% higher initial water flux and total solids rejection as high as ~62% when operated with 2.5 M Na3PO4. The improved performance is attributed to the nanofibrous architecture and zwitterionic surface chemistry, which together reduced fouling and reverse solute transport. These findings highlight the potential of engineered zwitterionic nanofibrous membranes as robust alternatives to commercial FO membranes for sustainable produced water treatment.
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Improving anti-fouling properties of alumina tubular microfiltration membranes through the use of hydrophilic silica nanoparticles for oil/water separation
In this study, hydrophilic silica nanoparticles (Si NPs) were used to modify α-alumina tubular membranes to improve their performance in terms of flux, oil rejection, and anti-fouling properties. Our work focuses on enhancing membrane performance, particularly for difficult applications such as produced water treatment. The prepared membranes were applied for oil-in-water emulsion treatment. After coating hydrophilic Si NPs, the oil contact angle improved from 133.8° to 171.4°. To prevent Si NPs from leaching off the surface of α-alumina tubular membranes, polyvinyl alcohol was used to coat the membranes as a pre-treatment step before Si NP modification. After coating the membrane with Si NPs, the roughness of the membrane surface decreased, likely leading to less fouling. After coating Si NPs, Total Organic Carbon rejection increased from 93.1% for pristine α-alumina tubular membranes to 97.7% for silica-modified membranes because of hydrophilic improvements of the modified membranes. The Si NP coating improved the anti-fouling property of membranes with the flux recovery ratio increasing from 71.3% for pristine α-alumina tubular membranes to 85.9% for silica-modified membranes. Scanning Electron Microscopy, Energy- dispersive X-ray spectroscopy, oil contact angle, and Atomic Force Microscopy characterization tests were done. The tests showed successful Si NPs impregnation and altered wettability.
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- Award ID(s):
- 1946093
- PAR ID:
- 10494889
- Publisher / Repository:
- Taylor & Francis
- Date Published:
- Journal Name:
- Separation Science and Technology
- Volume:
- 58
- Issue:
- 14
- ISSN:
- 0149-6395
- Page Range / eLocation ID:
- 2422 to 2436
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1080/01496395.2023.2259605
