Introduction Of Nanofibers Research Articles

Thin film nanocomposite membranes fabricated via 2D ZIF-67 nanosheets and 1D nanofibers with ultrahigh water flux for dye removal from wastewater

Thin-film nanocomposite (TFN) membranes based on metal–organic frameworks (MOFs) have received increasing attention in the field of water treatment. However, TFN membranes with both high permeance and rejection rates are highly desired. In this study, ultra-thin ZIF-67 was synthesized and TFN membranes were fabricated by combining the obtained 2D ZIF-67 with cellulose nanofibers (CNF) and carbon nanotubes (CNTs). The nanofibers not only fill the gaps between the ZIF-67 nanosheets but also form an intercalation layer between the ZIF-67 nanosheets and function as a water transport pathway, leading to a significant enhancement of water permeance. By introducing CNF into the ZIF-67-embedded matrix, the dye rejection rates increase to 96.8 % and 93.3 %, respectively, with water permeance of about 90.0 L⋅m−2⋅h−1⋅bar−1. Further introducing CNT into the CNF/ZIF-67 membrane further improved the water permeance to 207.8 L⋅m−2⋅h−1⋅bar−1, while a dye rejection rate of 95.1 % was documented. The results indicate that the introduction of nanofibers into 2D MOF matrix to form TFN membranes has great potential for wastewater treatment.

Исследование ледовых композиционных материалов, армированных нанодисперсными волокнами оксида алюминия, методами ядерного магнитного резонанса

The aqueous suspensions of nanosized alumina fibers and ice composite materials based on them were studied using Pulsed-Field Gradient NMR and Magnetic Resonance Imaging methods. It is shown that the introduction of nanofibers does not lead to noticeable structural effects in suspensions in the concentration range of 1 - 10 wt. % Al2O3. It was found that a high concentration of filler significantly changes the morphology and texture of the ice matrix in composites: it becomes more homogeneous, with a high degree of continuity; when the melting front passes through, internal regions of thawing or failure of the integrity of the composite are not visualized. Yet the introduction of nanofibers into ice composites has a weak effect on the quantitative dynamics of heat transfer processes, making the rate of freezing/thawing front propagation to be similar in different samples at comparable temperatures of the process.

Electrospun Polyamide Nanofiber-Reinforced Hybrid Syntactic Foams

ABSTRACTThe potential of polyamide nanofibers towards improving the mechanical properties of syntactic foams is demonstrated. Nylon nanofibers were prepared by electrospinning, and the operating parameters, namely solution concentration and flow rate varied to obtain fibers of requisite dimensions. The fibrous mats were employed for reinforcing cenosphere-epoxy syntactic foams. The introduction of nanofibers (0.25% v/v), when placed perpendicularly to the direction of loading led to a marginal improvement (∼7%) in the compressive strength. In comparison, the flexural properties of the reinforced foam was significantly higher, with 75 and 62% enhancement in the flexural strength and elongation, respectively.

Novel Hydrogen Peroxide Biosensor Based on Hemoglobin Combined with Electrospinning Composite Nanofibers

A facile strategy to construct an amperometric biosensor was described for the determination of hydrogen peroxide (H2O2). This biosensor relied on an electrospinning gold nanoparticle-chitosan-poly(vinyl alcohol) composite nanofibers modified ITO electrode, followed by immobilization of hemoglobin (Hb) on the surface. The introduction of nanofibers and gold nanoparticles in the modification of electrode surface not only enhanced the surface area of the modified electrode for enzyme immobilization but also facilitated the electron transfer rate. Under optimum conditions, the sensor was characterized in terms of its morphology by scanning electron microscopy and its electroactivity by cyclic voltammetry and chronoamperometry. Scanning electron microscopy revealed that the obtained nanofibers were uniform. The chronoamperometric behavior of the modified electrode indicated that the immobilized Hb retained electrochemical activity inside the electrospinning fibrous membranes. The electrode responded linearly to H2O2 in a wider concentration range of 5.6 × 10−7 M to 5.2 × 10−2 M with a low detection limit (S/N = 3) of 1.98 × 10−7 M and a short response time of ∼4 s, suggesting a much better performance than that of other sensors. Moreover, the biosensor achieved bulk production and exhibited superior properties for the sensitive determination of H2O2, studied namely, long-term stability, good reproducibility, and high selectivity.