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Aguilar S, Bustillos S, Xue S, Ji CH, Mak WH, Rao E, McVerry BT, La Plante EC, Simonetti D, Sant G, Kaner RB. Enhancing Polyvalent Cation Rejection Using Perfluorophenylazide-Grafted-Copolymer Membrane Coatings. ACS APPLIED MATERIALS & INTERFACES 2020; 12:42030-42040. [PMID: 32876431 DOI: 10.1021/acsami.0c07111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Surface modification offers a straightforward means to alter and enhance the properties and performance of materials, such as nanofiltration membranes for water softening. Herein, we demonstrate how a membrane's surface charge can be altered by grafting different electrostatically varying copolymers onto commercial membrane surfaces using perfluorophenylazide (PFPA) photochemistry for enhanced ion separation performance. The native membrane's performance-i.e., in terms of divalent cation separation-with copolymer coatings containing a positively charged quaternary ammonium (-N(Me)3+), a negatively charged sulfonate (-SO3-), and an essentially neutral zwitterion (sulfobetaine, -N(Me)2R2+, and -SO3-), respectively, indicates that: (a) the sulfonated polymer induces robust Coulombic exclusion of divalent anions as compared to the negatively charged native membrane surface on account of its higher negative charge; (b) the positively charged ammonium coating induces exclusion of cations more effectively than the native membrane; and significantly, (c) the zwitterion polymer coating, which reduces the surface roughness and improves wettability, in spite of its near-neutral charge enhances exclusion of both divalent cations and anions on account of aperture sieving by the compact zwitterion polymer that arises from its ability to limit the size of ions that transport through the polymer along with dielectric exclusion. The outcomes thereby inform new pathways to achieve size- and charge-based exclusion of ionic, molecular, and other species contained in liquid streams.
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Affiliation(s)
- Stephanie Aguilar
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Steven Bustillos
- Laboratory for the Chemistry of Construction Materials (LC2), Department of Civil and Environmental Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Shuangmei Xue
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Chen-Hao Ji
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Wai H Mak
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Ethan Rao
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Brian T McVerry
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Erika Callagon La Plante
- Laboratory for the Chemistry of Construction Materials (LC2), Department of Civil and Environmental Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
- Institute for Carbon Management, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Materials Science and Engineering, University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Dante Simonetti
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
- Institute for Carbon Management, University of California, Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Gaurav Sant
- Laboratory for the Chemistry of Construction Materials (LC2), Department of Civil and Environmental Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
- Institute for Carbon Management, University of California, Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Richard B Kaner
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
- Institute for Carbon Management, University of California, Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
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Xiao L, Davenport DM, Ormsbee L, Bhattacharyya D. Polymerization and Functionalization of Membrane Pores for Water Related Applications. Ind Eng Chem Res 2014; 54:4174-4182. [PMID: 26074669 PMCID: PMC4461045 DOI: 10.1021/ie504149t] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 12/15/2014] [Accepted: 12/15/2014] [Indexed: 11/28/2022]
Abstract
Poly(vinylidene fluoride) (PVDF)
was modified by chemical treatments
in order to create active double bonds to obtain covalent grafting
of poly(acrylic acid) (PAA) on membrane. The attenuated total reflectance
Fourier transform infrared (ATR-FTIR) spectrum confirms the formation
of conjugated C=C double bonds with surface dehydrofluorination.
The membrane morphology was studied by scanning electron microscopy
(SEM). The surface composition was characterized by X-ray photoelectron
spectroscopy (XPS). The thermal stability of the dehydrofluorinated
membrane (Def-PVDF) and functionalized membranes were investigated
by differential scanning calorimetry (DSC) analysis. The influence
of covalently attached PAA on Def-PVDF membrane has been investigated
to determine its effect on the transport of water and charged solute.
Variations in the solution pH show an effect on both permeability
and solute retention in a reversible fashion. Metal nanoparticles
were also immobilized in the membrane for the degradation of toxic
chlorinated organics from water. In addition, PVDF membranes with
an asymmetric and sponge-like morphology were developed by immersion-precipitation
phase-inversion methods in both lab-scale and large-scale. The new
type of spongy PVDF membrane shows high surface area with higher yield
of PAA functionalization. The ion-capacity with Ca2+ ions
was also investigated.
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Affiliation(s)
- Li Xiao
- Department of Chemical and Materials Engineering and Department of Civil Engineering, University of Kentucky , Lexington, Kentucky 40506, United States
| | - Douglas M Davenport
- Department of Chemical and Materials Engineering and Department of Civil Engineering, University of Kentucky , Lexington, Kentucky 40506, United States
| | - Lindell Ormsbee
- Department of Chemical and Materials Engineering and Department of Civil Engineering, University of Kentucky , Lexington, Kentucky 40506, United States
| | - Dibakar Bhattacharyya
- Department of Chemical and Materials Engineering and Department of Civil Engineering, University of Kentucky , Lexington, Kentucky 40506, United States
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