Journal article
Functionalized polymer-iron oxide hybrid nanofibers: Electrospun filtration devices for metal oxyanion removal
Water research (Oxford), Vol.117, pp.207-217
06/15/2017
DOI: 10.1016/j.watres.2017.04.007
PMID: 28399482
Abstract
Via a single-pot electrospinning synthesis, we developed a functionalized polymer-metal oxide nanofiber filter for point of use (POU) water treatment of metal oxyanions (e.g., arsenate and chromate). Polyacrylonitrile (PAN) functionalization was accomplished by inclusion of surface-active, quaternary ammonium salts (QAS) [cetyltrimethylammonium bromide (CTAB) or tetrabutylammonium bromide (TBAB)] that provide strong base ion exchange sites. Embedded iron oxide [ferrihydrite (Fh)] nanoparticles were used for their established role as metal sorbents. We examined the influence of QAS and Fh loading on composite properties, including nanofiber morphology, surface area, surface chemical composition, and the accessibility of embedded nanoparticles to solution. Composite performance was then evaluated using kinetic, isotherm, and pH-edge sorption experiments with arsenate and chromate, and benchmarked to unmodified PAN nanofibers and freely dispersed Fh nanoparticles. We also assessed the long-term stability of QAS in the composite matrix. For composites containing QAS or Fh nanoparticles, increasing QAS/Fh nanoparticle loading generally yielded increasing metal oxyanion uptake. The optimized composite (PAN 7 wt%, Fh 3 wt%, TBAB 1 wt%) exhibited two distinct sites for simultaneous, non-competitive metal binding (i.e., iron oxide sites for arsenate removal via sorption and well-retained QAS sites for chromate removal via ion exchange). Moreover, surface-segregating QAS enriched Fh abundance at the nanofiber surface, allowing immobilized nanoparticles to exhibit reactivity comparable to that of unsupported (i.e., suspended or freely dispersed) nanoparticles. To simulate POU application, the optimized composite was tested in a dead-end, flow-through filtration system for arsenate and chromate removal at environmentally relevant concentrations (e.g., μg/L) in both idealized and simulated tap water matrices. Performance trends indicate that dual mechanisms for uptake are maintained in kinetically limited regimes. Although chromate removal via ion exchange is more susceptible to interfering counter-ions, arsenate removal in simulated tap water indicates that ∼130 g of the composite could produce an individual's annual supply of drinking water (assuming an influent contaminated with 100 μg As/L, which is 10 times the current MCL).
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•A functionalized polymer-iron oxide composite nanofiber filter was developed.•The composite exhibits dual surface-active sites for chromate and arsenate removal.•Quaternary ammonium surfactants create ion exchange sites for chromate uptake.•Embedded nano-ferrihydrite sorbs arsenate with capacity equal to dispersions.
Details
- Title: Subtitle
- Functionalized polymer-iron oxide hybrid nanofibers: Electrospun filtration devices for metal oxyanion removal
- Creators
- Katherine T Peter - Department of Civil and Environmental Engineering, University of Iowa, United StatesAdam J Johns - Department of Civil and Environmental Engineering, University of Iowa, United StatesNosang V Myung - Department of Chemical and Environmental Engineering, University of California, Riverside, United StatesDavid M Cwiertny - Department of Civil and Environmental Engineering, University of Iowa, United States
- Resource Type
- Journal article
- Publication Details
- Water research (Oxford), Vol.117, pp.207-217
- Publisher
- Elsevier Ltd
- DOI
- 10.1016/j.watres.2017.04.007
- PMID
- 28399482
- ISSN
- 0043-1354
- eISSN
- 1879-2448
- Grant note
- name: US EPA Science to Achieve Results, award: R835177; name: NSF Graduate Research Fellowship, award: 1048957
- Language
- English
- Date published
- 06/15/2017
- Academic Unit
- Center for Health Effects of Environmental Contamination; Civil and Environmental Engineering; Public Policy Center (Archive); Chemical and Biochemical Engineering
- Record Identifier
- 9983992002802771
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