Bioinspired Mineralization of Nanofibers for Water Purificatio

The synthetic modification of textile surfaces using inorganic nanomaterials is crucial to the development of functional textiles, having desirable properties such as water repellency, antimicrobial and water filtration. Nature provides unique examples of nanostructures that are inherently multi-functional. Mimicking these naturally occurring nanostructures will enable the development of novel textile nanotechnologies. In this work, three approaches for inorganic mineralization were studied and all were inspired by nature.;Nanofibrous adsorbents were developed in mimicry of human bone formation. Human bone comprises collagen fibrils and hydroxyapatite nanocrystals, which attach alongside the collagen fibrils. Proteins absorbed into the voids of collagen fibrils nucleate the growth of nanocrystals. Polymerized micelles were synthesized to emulate the macromolecular structure and charge density of proteins. Spherical calcium carbonate (CaCO3) particles threaded onto nanofibers upon dipping them into alternating solutions of aqueous calcium chloride (CaCl2) and sodium carbonate (Na2CO3). Polymerized micelles, at the nanofiber surface, attracted Ca2+ and CO32- ions to form denser CaCO3 coatings with the vaterite crystalline form, than other polyelectrolyte seeds. The vaterite phase enhanced anthraquinone dye adsorption from water.;Nanowrinkles formed on the surface of crosslinked poly(vinyl alcohol) nanofibers after repetitive cycles of titanium dioxide (TiO2) sol-gel synthesis. This synthetic approach to nanowrinkling mimicked the natural occurrence of skin wrinkling. Wrinkles form when bilayers experience different amounts of strain between each layer. Nanofibers were dipped in alternating solutions of TiO2 precursors (titanium tetraisopropoxide (TTIP) in isopropanol (IPA) and water for up to 5 cycles. TTIP hydrolyzed to condense in the form of TiO2 nanoparticles. PVA nanofibers swelled in water and deswelled in TTIP solutions. The repetitive swelling-deswelling, focused internal stress along stiff TiO2 nanoparticles to ultimately induce nanowrinkles along the nanofiber surfaces. This unique hierarchical structure could benefit the design of separation membranes for energy storage and superhydrophobic surfaces.;Lastly, manganese oxidizing soil fungi were grown directly onto nanofibers as biocatalysts for mineralization. Several soil fungi can catalyze manganese oxide (Mn(III/IV)O) mineralization by secreting oxidative enzymes that transforms Mn(II) to Mn(IV). Biogenic manganese oxides are known to remove harmful heavy metal ions from water much better than synthetic minerals due to their imperfect crystalline forms. In this study, Coniothyrium sp. and Coprinellus sp. soil fungi that were isolated from the superfund site (Lot 86, Farm Unit #1) were incubated in the presence of nanofibers. Upon their attachment to nanofibers containing manganese chloride (MnCl 2), Coniothyrium sp. catalyzed the conformal deposition of Mn(III/IV)O along hyphae and nanofibers, but Coprinellus sp. catalyzed Mn(III/IV)O only along its hyphae. Mn(III/IV)O coated nanofibers (with and without Coniothyrium sp.) were more effective against Mn(II) and copper (Cu(II)) removal than for lead (Pb(II)). Thus, nanofibrous scaffolds for inorganic nanomaterials and microorganisms can lead to the development of novel functional materials.;Throughout these studies, the surface chemistry of nanofibers- as dictated by seeding with ions, polyelectrolytes or hydroxyl groups populating the surface- was found to have the greatest influence on inorganic mineral nucleation and growth mechanisms.