Functionalized polymer-iron oxide hybrid nanofibers: Electrospun filtration devices for metal oxyanion removal
| Autor: | Katherine T. Peter, Adam J. Johns, David M. Cwiertny, Nosang V. Myung |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Environmental Engineering
Polymers Inorganic chemistry Nanofibers Oxide Oxyanion 02 engineering and technology 010501 environmental sciences 01 natural sciences Water Purification chemistry.chemical_compound Waste Management and Disposal 0105 earth and related environmental sciences Water Science and Technology Civil and Structural Engineering Chromate conversion coating Ion exchange Chemistry Ecological Modeling Arsenate Polyacrylonitrile 021001 nanoscience & nanotechnology Pollution Chemical engineering Metals Nanofiber Water treatment Adsorption 0210 nano-technology Water Pollutants Chemical |
| Zdroj: | Water Research. 117:207-217 |
| ISSN: | 0043-1354 |
| DOI: | 10.1016/j.watres.2017.04.007 |
| Popis: | 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). |
| Databáze: | OpenAIRE |
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