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Abstract Low-density, flexible and high-performance electromagnetic interference (EMI) shielding materials are urgently required to address the increasingly serious problem of radiation pollution. Ni-Co alloys with intrinsic conductivity and magnetism are good candidates for providing excellent EMI shielding performance. However, their high density and poor flexibility severely restrict their further applications in some specific fields. Herein, lightweight and flexible Ni-Co alloy nanoparticle-coated PAN-PU (P@Ni-Co) nanofiber membrane is fabricated through the combination of the electrospinning technique and the electroless deposition process, and it is employed as an effective EMI shielding material. Due to its remarkable conductivity of 1139.6 S/cm and the satisfactory saturation magnetization value of 49.6 emu/g, P@Ni-Co hybrid membrane with a thickness of 0.180 mm and a density of 0.59 g cm−3 exhibits excellent electromagnetic interference shielding effectiveness (EMI SE) of >68 dB over a wide frequency band (8–26.5 GHz); moreover, the average EMI SE reached as high as 77.8 dB with an absolute EMI shielding effectiveness (SSE T) of 7325.8 dB cm2·g−1, which are higher than those for most of the reported EMI shielding materials. Compared to reflection, absorption makes a much larger contribution to the total EMI shielding effectiveness. These results suggest that Ni-Co alloy nanoparticle-coated PAN-PU nanofiber membrane would be very promising for applications as a thinner and lighter EMI shielding material. Graphical abstract Image 1 Highlights • P@Ni-Co nanofiber membrane is prepared via electrospinning and electroless plating. • P@Ni-Co exhibits remarkable conductivity and satisfying magnetism. • P@Ni-Co is employed as lightweight and flexible EMI shielding material. • The average EMI SE could reach 77.8 dB over wide frequency band (8–26.5 GHz). • Absorption makes much larger contribution to total EMI shielding effectiveness. [ABSTRACT FROM AUTHOR]

Polydopamine (PDA) and MnO 2 have been proven to be promising adsorbents to capture Pb 2+ from wastewater. In this study, MnO 2 was in-situ loaded onto flexible electrospun polyacrylonitrile (PAN) fibers by the assistance of polydopamine coating (MnO 2 /PDA/PAN fibers) and the as-obtained MnO 2 /PDA/PAN fibers were utilized for the removal of Pb 2+ from water. The structure and chemical composition of MnO 2 /PDA/PAN fibers were characterized in detail. The results indicated that the PDA coating onto PAN fibers can’t be neglected for loading MnO 2 . This preparation of MnO 2 /PDA/PAN fibers could avoid the agglomeration of MnO 2 particles and make the adsorbent separate easily from the adsorption solution. The adsorption experiments showed that the adsorption process toward Pb 2+ by MnO 2 /PDA/PAN fibers followed pseudo-second-order model and Langmuir isotherm model. In comparison with PDA/PAN fibers and MnO 2 /PAN fibers, MnO 2 /PDA/PAN fibers showed higher Pb 2+ adsorption capacity. The maximum adsorption capacity calculated from Langmuir model was 185.19 mg/g, which is higher than most of the reported PDA or MnO 2 based Pb 2+ adsorbents. The adsorption toward Pb 2+ by MnO 2 /PDA/PAN fibers still maintained stability after five adsorption/desorption cycles. In addition, the fiber adsorbent could also adsorb Pb 2+ from real industrial effluent with removal efficiency above 95%. This work indicates that MnO 2 /PDA/PAN fibers have great potential to be used as effective adsorbents for practical Pb 2+ removal. [ABSTRACT FROM AUTHOR]

Electrospun nanofibrous membranes with a large number of nano-sized micropore possess excellent potential in the applications of oil harvesting and oil/water separation. In this study, a green and simple approach was successfully applied to fabricate superhydrophobic and superoleophilic nanofibrous mats through the combination of electrospinning and electroless plating techniques. We designed hierarchical structure by immobilizing Cu nanocluster on the surfaces of Ag seeds loaded electrospun polyacrylonitrile (PAN) nanofibers and followed with a surface modification process by n-hexadecyl mercaptan immersion. The fabricated superhydrophobic PAN nanofibrous membranes showed the wetting property with a water contact angle (WCA) of 154.6° and a sliding angle lower than 8.0°. Owing to the super hydrophobicity and their high porosity of 94.40%, the superhydrophobic nanofibrous mats were sequentially employed for both oil harvesting and oil/water separation to purify the water which was contaminated by various organic solvents and oils. The results indicated that the nanofibrous mats showed a very high separation efficiency and rapid separating speed only by gravity-driven. In addition, these mats also exhibited excellent mechanical strength, high stability and remarkable recyclability in terms of superhydrophobicity and oil separation/adsorbency performance. These findings demonstrate that composite nanofibers are promising candidates for oil-contaminated water purification. [ABSTRACT FROM AUTHOR]

In this study, a series of undoped and Eu-doped SnO 2 nanofibers were synthesized via a simple electrospinning technique and subsequent calcination treatment. Field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were carefully used to characterize the morphologies, structures and chemical compositions of these samples. The results reveal that the as-prepared nanofibers are composed of crystallite grains with an average size of about 10 nm and Eu 3+ ions are successfully doped into the SnO 2 lattice. Compared with pure SnO 2 nanofibers, Eu-doped SnO 2 nanofibers demonstrate significantly enhanced sensing characteristics (e.g., large response value, short response/recovery time and outstanding selectivity) toward acetone vapor, especially, the optimal sensor based on 2 mol% Eu-doped SnO 2 nanofibers shows the highest response (32.2 for 100 ppm), which is two times higher than that of the pure SnO 2 sensor at an operating temperature of 280 °C. In addition, the sensor exhibits a good sensitivity to acetone in sub-ppm concentrations and the detection limit could extend down to 0.3 ppm, making it a potential candidate for the breath diagnosis of diabetes. [ABSTRACT FROM AUTHOR]

A novel water-insoluble sericin/β-cyclodextrin/poly (vinyl alcohol) composite nanofiber adsorbent was prepared by electrospinning and followed by thermal crosslinking for removal of cationic dye methylene blue from aqueous solution. Fourier transform infrared spectroscopy and solubility experiments confirmed that sericin and β-cyclodextrin were incorporated into the nanofibers and the crosslinking reaction occurred successfully. Kinetics, isotherms and thermodynamics analysis were studied for adsorption of methylene blue. The adsorption process is better fitted with the pseudo-second-order model and Langmuir isotherm model. The maximum adsorption capacities are 187.97, 229.89, and 261.10 mg/g at the temperatures 293, 313 and 333 K, respectively. Thermodynamic parameters showed that methylene blue adsorption was endothermic and spontaneous. In addition, the fiber membrane adsorbent could be easily separated from dye solution and showed high recyclable removal efficiency. All these results suggest that crosslinked sericin/β-cyclodextrin/poly(vinyl alcohol) composite nanofibers could be potential recyclable adsorbents in dye wastewater treatment. [ABSTRACT FROM AUTHOR]

A phosphorylated PAN-based nanofiber (P-PAN) mat is prepared by electrospinning technique followed by chemical grafting modification, which is suitable for metal adsorption due to their high adsorption capacity for metal ions. The content of phosphorous in phosphorylated PAN fibers is 5.45 mg/g. Adsorption isotherms and adsorption kinetics are used to examine the fundamental adsorption properties. It is found that the adsorption isotherms of P-PAN nanofibers toward Pb 2+ , Cu 2+ , and Ag + are fitted better with Freundlich isotherm model and the adsorption of Cd 2+ is fitted better with Langmuir isotherm model. Kinetics of the Pb 2+ , Cu 2+ , Ag + , and Cd 2+ ions adsorption are found to follow pseudo-second-order rate equation. Through the analysis of the XPS data, phosphorous and nitrogen containing functional groups play the major role in the complexation with heavy metal ions. In addition, the obtained phosphorylated PAN fibers also show high recyclable removal efficiency through the adsorption/desorption experiments. This study provides a promising adsorbent in heavy metal ions wastewater treatment. [ABSTRACT FROM AUTHOR]

Abstract: Chitosan and sericin are natural and low cost biomaterials. Both biomaterials displayed good compatibility to human tissues and antibacterial properties for biomedical application. In this study, we have successfully fabricated chitosan/sericin composite nanofibers by electrospinning. The obtained composite nanofibers were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) studies. The composite nanofibers had good morphology with diameter between 240nm and 380nm. In vitro methyl thiazolyl tetrazolium (MTT) assays demonstrated that the chitosan/sericin composite nanofibers were biocompatible and could promote the cell proliferation. Furthermore, the composite nanofibers showed good bactericidal activity against both of Gram-positive and Gram-negative bacteria. Thus, the chitosan/sericin composite nanofibers are promising for wound dressing applications. [Copyright &y& Elsevier]

The surface modification is one of the most effective methods to improve the bioactivity and cell affinity effect of electrospun poly(ε-caprolactone) (PCL) fibers. In the present study, chitosan (CS), a cationic polysaccharide, was used to modify the surface of electrospun PCL fibers. To obtain strong interaction between CS and PCL fibers, negatively charged PCL fibers were prepared by the incorporation of acid-treated carbon nanotubes (CNTs) into the fibers. In this way, the positively charged chitosan could be immobilized onto the surface of PCL fibers tightly by the electrostatic attraction. Besides, the incorporation of CNTs could significantly improve the mechanical strength of electrospun PCL fibers even after the CS modification, which guaranteed their usability in practical applications. The CS modification could effectively improve the wettability and bioactivity of electrospun PCL fibers. Cultivation of L929 fibroblast cells on the obtained fibers and the antibacterial activity were both evaluated to discuss the influence of chitosan modification. The results indicated that this modification could enhance the cell proliferation and antibacterial ability in comparison to the non-modified groups. [ABSTRACT FROM AUTHOR]

Recently, electrically conductive biomaterial scaffolds have shown great potential in tissue regeneration. Herein, we reported an electrically conductive polyaniline (PANI) coated poly(ε-caprolactone) (PCL) electrospun micron-fiber scaffold for the enhanced attachment and proliferation of human umbilical vein endothelial cells (HUVECs) under electrical stimulation conditions. After the O 2 plasma treatment toward PCL electrospun fiber, PANI could be polymerized onto their surfaces successfully. The obtained PANI-PCL fibers were characterized by SEM observations, FT-IR spectra, XPS analysis, and water contact angle measurement. The mechanical tests indicated that the fibers could satisfy the practical vascular scaffold requirements. The conductivity of the PANI-PCL fibers was 6.71 × 10 − 3 S/cm which could provide a conductive in-vitro platform to study the effect of electrical stimulation on HUVECs proliferation. When PANI-coated PCL fibers were compared with PCL fibers, HUVECs exhibited highly enhanced adhesion and viability, especially under electrical stimulation (ES) of 200, 300, and 400 mV/cm. Proliferation of HUVECs on PANI-PCL fibers was strongly dependent on electrical stimulation intensity. The results showed new insights into conductive scaffolds for vascular tissue engineering. [ABSTRACT FROM AUTHOR]

[Display omitted] • Functionalized electrospun nanofibers were applied for the uranium extraction. • Hyperbranched amidoxime groups with assistant groups were grafted. • Photothermal conversion ability was also introduced into the fibers. • The nanofiber adsorbents showed good antibacterial activity. • The uranium extraction capacity reached 9.54 mg g−1 from natural seawater. Uranium extraction from natural seawater is critical to addressing the shortage of uranium resources, but it is a giant challenge. The amidoxime-based adsorbent is regarded as one of the most promising materials for uranium capture, whereas still suffers from low adsorption site utilization and poor selectivity toward U(VI) against V(V). Herein, hyperbranched amidoxime group grafted photothermal electrospun fibers (AOPEI-C-PAN fibers) were reported for highly efficient uranium extraction from seawater. Carbon nanotubes (CNTs) were blended into the electrospun fibers to introduce the photothermal character. Hyperbranched grafting could improve the content of the amidoxime group and bring an assistant group (the amine group). Owing to the large content of functional groups, synergetic coordination interaction and photothermal conversion ability, the novel fiber adsorbents realized a fast adsorption rate (shortening the equilibrium time to 36 h from 60 h compared with the dark condition), high uranium uptake (1738.5 mg g−1 from the Langmuir model) from the uranium spiked seawater and excellent selectivity in U/V binary system (selectivity coefficient = 85.8). Furthermore, Ag nanoparticles could also be loaded onto the CNTs to endow the fibers with antibacterial activity, thereby preventing biofouling. As a result, the uranium extraction capacity of the fiber adsorbent reached 9.54 mg g−1 after 28 days' simulated sunlight irradiation of contact with circular seawater, which is 62.0 % higher than that under dark condition. This study reveals that AOPEI-C-PAN fiber adsorbent holds great potential in practical uranium extraction applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hyperbranched phosphate groups were grafted onto electrospun nanofibers. • The proton transfer process could lead to the zwitterionic structures. • The fiber adsorbents exhibited excellent adsorption performance towards UO 2 2+. • The nanofibers also showed anti-bacterial adhesion and anti-protein adhesion. • The fiber adsorbents had good potential for the uranium extraction from seawater.. The development of efficient adsorbents with anti-biofouling properties for uranium extraction from seawater is highly attractive to meet the growing demands for energy. However, traditional fiber adsorbents still suffer from the challenge of weak binding energy, low functional group density, and inefficient antifouling ability. Herein, inspired by the structures of phospholipid, the bio-inspired zwitterionic phosphate groups were created onto the electrospun nanofibers to manipulate the affinity with uranium and the anti-biofouling property. Additionally, hyperbranched grafting reaction together with thin diameters of the fibers were applied to significantly improve the available density of functional groups. The constructed hyperbranched zwitterionic phosphate groups functionalized nanofiber adsorbents (ZP-PAN fibers) exhibited high distribution coefficient k d (7.38 × 106 mL/g) and large adsorption capacity (1294.0 mg g−1) in the uranium-spiked seawater, surpassing most of reported polymeric adsorbents. ZP-PAN fibers also showed good selectivity against competitive cations and stable reusability. Owing to their zwitterionic structures, ZP-PAN fibers had satisfactory anti-adhesive ability toward bacteria and protein. Consequently, the uranium could be effectively extracted by ZP-PAN fibers from natural seawater with the extraction capacity of 8.1 mg g−1 after contacting with seawater for 15 days. This work demonstrates a new functionalization selection for nanofiber materials and provides a promising adsorbent in the practical uranium extraction from seawater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel cationic electrospun nanofibers (NCE fibers) were designed and synthesized. • Specific anion traps with hydrophobic microenvironment were constructed. • NCE fibers exhibited fast kinetics and high uptake for ReO 4 −. • NCE fibers showed good removal depth and satisfying selectivity toward ReO 4 −. • The column adsorption was also conducted with the treatment capacity of 1540 BV. Developing cationic adsorbents for efficient radioactive pertechnetate (99TcO 4 −) removal from water is of great significance in both nuclear fuel management and nuclear-related environmental treatment fields. However, tremendous efforts should be taken to improve the comprehensive performance of the adsorbent materials. Herein, novel cationic electrospun nanofibers were synthesized via the blending electrospinning from the branched polyethylenimine based solution and the following quaternization reaction by benzyl bromide. Consequently, abundant specific anion traps with hydrophobic microenvironment were constructed on the fibers. The obtained fiber adsorbents were systematically investigated to remove perrhenate (ReO 4 −) ions (the nonradioactive surrogate for TcO 4 −), which exhibit satisfying adsorption performance in several aspects: high adsorption capacity (943 mg g−1), fast kinetics (30 min), good removal depth (distribution coefficient = 1.1 × 106 mL g−1), large dynamic column adsorption volume (1540 bed volume), and excellent ReO 4 − capture from solution with high ionic strength or acidity/alkalinity. The adsorption performance surpassed all macroscopic shapeable adsorbents and many powdery advanced porous materials, owing to their abundant adsorption sites, tailored anion traps and macroscopic fibrous structures. Overall, this work gives a useful insight into designing novel adsorbents for effective TcO 4 −/ReO 4 − capture. [ABSTRACT FROM AUTHOR]