Yixia Zhao

Fabrication of porous Fe2O3/PTFE nanofiber membranes and their application as a catalyst for dye degradation

Novel porous polytetrafluoroethylene (PTFE) nanofiber membranes containing Fe2O3 (Fe2O3/PTFE), used as a heterogeneous catalyst, were prepared via a three-step method by electrospinning, immersion and calcination. The morphology and structure of porous Fe2O3/PTFE were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffractometer (XRD). The effects of the thickness of the as-spun nanofiber membrane, the immersion time and impregnating solution concentration on the content of Fe2O3 which was the active component were discussed. The degradation of Acid Red with hydrogen peroxide catalyzed by the porous Fe2O3/PTFE under UV irradiation was investigated. UV-vis and ESR techniques provided an insight into the nature of the degradation products and the formed active species. The results showed that Fe2O3 was successfully supported on the surface of porous PTFE nanofibers. The porous Fe2O3/PTFE nanofiber membrane prepared under the optimized parameters possessed high photocatalytic activity without any dye adsorption and could be recycled by simple filtration.

Coaxial solution blowing of modified hollow polyacrylonitrile (PAN) nanofiber Fe complex (Fe-AO-CSB-HPAN) as a heterogeneous Fenton photocatalyst for organic dye degradation

As a novel photocatalyst supporting material, one-dimensional hollow PAN nanofiber mat (HPAN) was successfully fabricated via coaxial solution blowing method (CSB), which we named CSB-HPAN. Then modified hollow PAN Fe complex (Fe-AO-CSB-HPAN) was prepared by the amidoximation and Fe coordination of AO-CSB-HPAN which used for the heterogeneous Fenton degradation of textile dyes. SEM, TEM and the digital photo revealed that CSB-HPAN has hollow structure, three-dimensional curly and loosely fibrous morphologies, which is beneficial for Fe3+ complexation, dye adsorption and degradation. The experiments of photocatalytic activity indicated that Fe-AO-CSB-HPAN showed excellent photocatalytic performance in the degradation of textile dyes in the presence of H2O2 under light irradiation. Meanwhile, 99% of RR195 molecules were decomposed by Fe-AO-CSB-HPAN in 35 min, which was faster than by conventional modified electrospinning PAN nanofiber Fe complex (Fe-AO-ES-PAN), due to the large surface area and loosely fibrous structure of Fe-AO-CSB-HPAN.

Electro-blown spun PS/PAN fibrous membrane for highly efficient oil/water separation

The preparation of high performance separation membrane is the key technology for developing efficient oil/water separation system. In this paper, hydrophilic/oleophilic Polystyrene (PS)/Polyacrylonitrile (PAN) bi-component membranes were prepared via electro-blown spinning (EBS) technique and exhibited extremely high oil flux. The addition of PAN component significantly enhanced the tensile strength of the PS based fibrous membranes and PS/PAN membrane with the weight ratio of 5:3 achieved a tensile strength of 2.1 MPa which was 3 times higher than pure PS membrane. The PS/PAN membranes demonstrated a high light oil flux up to 18000 l·m-2·h-1 and could remain the oil flux recovery ratio of 94.09 % after 10 cycles. The as-prepared membranes exhibited the superior oil/water separation performance with the separation efficiency higher than 99.5 % and have a great potential to deal with the oily waste water in the near future.

Emulsion-Blow Spun Self-Sustained Crystalline β-Silicon Carbide (SiC) Fiber Mat and Its Conductivity Property

ABSTRACT Micro-scale silicon carbide (SiC) fiber mat was produced by blowing of an oil-in-water (O/W) precursor emulsion process combined with a thermal curing treatment and a subsequent calcination at high temperature, which we named emulsion-blow spinning (EBS). An air flow with high velocity was used to attenuate the O/W emulsion jets, and the as-spun fibers can be successfully self-sustained to three-dimensional network structure. Polycarbosilane micelles (precursor) entrapped in an aqueous polyoxyethylene matrix resulted in SiC fibers with β crystalline after pyrolysis and ceramic process. The SiC fiber mat was tested with an excellent thermal stability and semi-conductivity, may have potential applications on electronic and energy storage. GRAPHICAL ABSTRACT

A novel flexible sensor for respiratory monitoring based on in situ polymerization of polypyrrole and polyurethane coating

Flexible conductive fabrics were made of knitted cotton fabric (KCF) based on in situ polymerization of polypyrrole and polyurethane coating. The properties of the conductive fabrics were investigated by a series of experiments such as SEM, FTIR, mechanics performance testing and washing fastness testing. The results showed that sensitivity, hysteresis, repeatability and washing fastness of knitted cotton fabrics with polypyrrole coating (KCF–P) greatly improved by surface polyurethane coating. Moreover, respiration monitoring data from volunteers also verified polyurethane coating to be thicker, with stronger output resistance variation. The knitted cotton fabrics with polypyrrole and polyurethane coating (KCF–PPU) have good application prospect in intelligent wearable fields.