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Yeoungsang Yun - One of the best experts on this subject based on the ideXlab platform.

  • reusable polyethylenimine coated polysulfone bacterial biomass Composite Fiber biosorbent for recovery of pd ii from acidic solutions
    Chemical Engineering Journal, 2016
    Co-Authors: Chulwoong Cho, Yeoungsang Yun, Su Bin Kang, Sok Kim, Sung Wook Won
    Abstract:

    Abstract This study presents the applicability and reusability of polyethylenimine (PEI)-coated polysulfone/Escherichia coli biomass Composite Fiber (PEI-PSBF) as a biosorbent for recovery of Pd(II) from acidic solutions. To enhance accessible surface area for Pd(II), PEI-PSBF was fabricated by first extruding polysulfone/biomass blend into water, next coating with PEI onto the surface of the polysulfone/biomass Composite Fiber (PSBF), and finally cross-linking with glutaraldehyde. In batch sorption experiments, adsorption capacity of the PEI-PSBF for Pd(II) was compared with that of PSBF to investigate the enhancement by PEI coating on adsorption. In result, the sorption kinetics and isotherms showed that the sorption kinetics of Pd(II) was fast, and the maximum sorption capacity of PEI-PSBF was 7.0 times higher than that of PSBF. Additionally, it was observed that the sorption capacity of PEI-PSBF was significantly depended on the HCl concentration and the optimal range of HCl concentration to achieve high sorption capacity was found to be 0.1–1 M. After adsorption, Pd(II) loaded on the PEI-PSBF could be recovered using a mixture of 0.1 M HCl and 0.01 M thiourea solution. The desorption efficiency of the mixture was approximately 97.4%. Finally, in regeneration test of the biosorbent, it was confirmed that the PEI-PSBF can be regenerated at least five times.

  • the role of biomass in polyethylenimine coated chitosan bacterial biomass Composite biosorbent Fiber for removal of ru from acetic acid waste solution
    Bioresource Technology, 2014
    Co-Authors: Sung Wook Won, In Seob Kwak, Yeoungsang Yun
    Abstract:

    The present study is aimed at understanding the role of bacterial biomass in functionalizing polyethylenimine (PEI)-coated bacterial biosorbent Fiber (PBBF). To make PBBF, chitosan/biomass Composite Fiber was coated with PEI and then cross-linked by glutaraldehyde. The role of biomass in the Fiber was investigated through sorption experiments and SEM, FTIR and XPS analyses with differently prepared Fiber sorbents. In the case that the chitosan Fiber was made without the biomass, it could not be coated with PEI. Meanwhile, the chitosan/biomass Composite Fiber could successfully coated with PEI and primary amine groups were significantly increased on the surface of the Fiber. Therefore, the biomass should be essential to make PEI-reinforced chitosan Fiber.

Jin U Kang - One of the best experts on this subject based on the ideXlab platform.

Xiuqin Zhao - One of the best experts on this subject based on the ideXlab platform.

  • efficient removal of lead and copper ions from water by enhanced strength toughness alginate Composite Fibers
    International Journal of Biological Macromolecules, 2019
    Co-Authors: Linhai Pan, Zhuqing Wang, Xiuqin Zhao
    Abstract:

    Abstract In this study, we designed and synthesized an enhanced strength-toughness alginate Composite Fiber by using graphene oxide as reinforcing filler for removing heavy metal ions from water media. The as-prepared alginate Composite Fiber exhibits high affinity to Pb2+ ion, and the maximum adsorption capacity for Pb2+ reached 386.2 mg/g, which is higher than the reported Pb2+-sorbent. The prepared round-shaped nanoFibers have relatively uniform distribution with a diameter of 400 nm, and the interlaced Fibers form porous structure that conducive to the rapid transport of heavy metal ions. Adsorption mechanism analysis shows that the alginate Composite Fibers combine heavy metals mainly by ion exchange and chemical coordination effects. Owing to the excellent mechanical properties of graphene oxide, the alginate Composite Fibers can be used repeatedly with minimal loss in performance.

Yaning Sun - One of the best experts on this subject based on the ideXlab platform.

  • enhanced mechanical and thermal properties of regenerated cellulose graphene Composite Fibers
    Carbohydrate Polymers, 2014
    Co-Authors: Mingwei Tian, Xiansheng Zhang, Kun Zhang, Shifeng Zhu, Xiaoqing Guo, Guangting Han, Xiaoning Tang, Yaning Sun
    Abstract:

    Abstract In this study, a wet spinning method was applied to fabricate regenerated cellulose Fibers filled with low graphene loading which was systematically characterized by SEM, TEM, FTIR and XRD techniques. Subsequently, the mechanical and thermal properties of the resulting Fibers were investigated. With only 0.2 wt% loading of graphene, a ∼50% improvement of tensile strength and 25% enhancement of Young's modulus were obtained and the modified Halpin–Tsai model was built to predict the mechanical properties of Composite Fibers. Thermal analysis of the Composite Fibers showed remarkably enhanced thermal stability and dynamic heat transfer performance of graphene-filled cellulose Composite Fiber, also, the presence of graphene oxide can significantly enhance the thermal conductivity of the Composite Fiber. This work provided a facile way to improve mechanical and thermal properties of regenerated cellulose Fibers. The resultant Composite Fibers have potential application in thermal insulation and reinforced fibrous materials.

  • enhanced mechanical and thermal properties of regenerated cellulose graphene Composite Fibers
    Carbohydrate Polymers, 2014
    Co-Authors: Mingwei Tian, Xiansheng Zhang, Kun Zhang, Shifeng Zhu, Xiaoqing Guo, Guangting Han, Xiaoning Tang, Lijun Qu, Yaning Sun
    Abstract:

    a b s t r a c t In this study, a wet spinning method was applied to fabricate regenerated cellulose Fibers filled with low graphene loading which was systematically characterized by SEM, TEM, FTIR and XRD techniques. Subsequently, the mechanical and thermal properties of the resulting Fibers were investigated. With only 0.2 wt% loading of graphene, a ∼50% improvement of tensile strength and 25% enhancement of Young's modulus were obtained and the modified Halpin-Tsai model was built to predict the mechanical proper- ties of Composite Fibers. Thermal analysis of the Composite Fibers showed remarkably enhanced thermal stability and dynamic heat transfer performance of graphene-filled cellulose Composite Fiber, also, the presence of graphene oxide can significantly enhance the thermal conductivity of the Composite Fiber. This work provided a facile way to improve mechanical and thermal properties of regenerated cellulose Fibers. The resultant Composite Fibers have potential application in thermal insulation and reinforced fibrous materials. © 2014 Elsevier Ltd. All rights reserved.

Satish Kumar - One of the best experts on this subject based on the ideXlab platform.

  • gel spun carbon nanotubes polyacrylonitrile Composite Fibers part iii effect of stabilization conditions on carbon Fiber properties
    Carbon, 2011
    Co-Authors: Yaodong Liu, Han Gi Chae, Satish Kumar
    Abstract:

    Abstract The oxidative stabilization process of gel-spun carbon nanotube (CNT)/polyacrylonitrile (PAN) Composite Fibers have been studied and optimized. Optimum stabilization time depends on both the applied tension and temperature. Various characterization methods including thermal shrinkage, dynamic mechanical analysis, infrared spectroscopy, and wide angle X-ray diffraction are used to monitor the chemical and structural evolution during stabilization and carbonization. The relationship between the stabilization conditions of CNT/PAN Composite Fiber and the tensile properties of the resulting carbon Fibers were investigated. By optimizing stabilization conditions, CNT/PAN based carbon Fibers with a tensile strength of 4 GPa and a tensile modulus of 286 GPa were obtained using batch carbonization processing at 1100 °C.

  • oriented and exfoliated single wall carbon nanotubes in polyacrylonitrile
    Polymer, 2006
    Co-Authors: Han Gi Chae, Marilyn L Minus, Satish Kumar
    Abstract:

    Abstract Polyacrylonitrile (PAN)/single wall carbon nanotubes (SWNT) Fibers were gel spun at 0, 0.5, and 1 wt% SWNT content to a draw ratio of 51. Structure, morphology, and mechanical and dynamic mechanical properties of these Fibers have been studied. PAN/SWNT Composite exhibited much higher electron beam radiation resistance than PAN. As a result, PAN lattice images could be easily observed in the Composite Fiber by high resolution transmission electron microscopy. The PAN/SWNT Composite Fiber also exhibited higher solvent resistance than the control PAN Fiber. UV–vis spectroscopy of highly drawn Fiber exhibited van Hove transitions, suggesting SWNT exfoliation upon drawing. SWNT exfoliation was also confirmed by high resolution transmission electron microscopy (HRTEM). At 1 wt% SWNT loading, Fiber storage modulus (at 1 Hz) increased by 13.9, 6.6, and 0.2 GPa at −75, 25, and 150 °C, respectively. This suggests that the load transfer ability and hence interfacial strength is increasing with decreasing temperature, even below the polymer's γ transition temperature.

  • a comparison of reinforcement efficiency of various types of carbon nanotubes in polyacrylonitrile Fiber
    Polymer, 2005
    Co-Authors: Han Gi Chae, T V Sreekumar, Tetsuya Uchida, Satish Kumar
    Abstract:

    Abstract Polyacrylonitrile (PAN)/carbon nanotubes (CNTs) Composite Fibers were spun from solutions in dimethyl acetamide (DMAc), using single wall (SWNTs), double wall (DWNTs), multi wall (MWNTs) carbon nanotubes, and vapor grown carbon nanoFibers (VGCNFs). In each case, CNT content was 5 wt% with respect to the polymer. Structure, morphology, and properties of the Composite Fibers have been characterized using X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, tensile tests, dynamic mechanical tests, as well as thermal shrinkage. While all nanotubes contributed to property improvements, maximum increase in modulus (75%) and reduction in thermal shrinkage (up to 50%) was observed in the SWNT containing Composites, and the maximum improvement in tensile strength (70%), strain to failure (110%), and work of rupture (230%) was observed in the MWNTs containing Composites. PAN orientation is higher in the Composite Fiber (orientation factor up to 0.62) than in the control PAN Fiber (orientation factor 0.52), and the PAN crystallite size in the Composite Fiber is up to 35% larger than in the control PAN (3.7 nm), while the overall PAN crystallinity diminished slightly. Nanotube orientation in the Composite Fibers is significantly higher (0.98 for SWNTs, 0.88 for DWNTs, and 0.91 for MWNTs and VGCNFs) than the PAN orientation (0.52–0.62). Improvement in low strain properties (modulus and shrinkage) was attributed to PAN interaction with the nanotube, while the improvement in high strain properties (tensile strength, elongation to break, and work of rupture) at least in part is attributed to the nanotube length. Property improvements have been analyzed in terms of nanotube surface area and orientation.

  • gel spinning of pva swnt Composite Fiber
    Polymer, 2004
    Co-Authors: Xiefei Zhang, Satish Kumar, T V Sreekumar, Tao Liu, K W Smith
    Abstract:

    Single wall carbon nanotubes (SWNT), polyvinyl alcohol (PVA), dimethyl sulfoxide (DMSO) and water, homogeneous dispersion has been prepared by stirring and sonication. This dispersion was extruded into Fiber via gel spinning. The modulus of the PVA/SWNT (3 wt%) Composite Fiber was 40% higher than that of the control PVA gel spun Fiber. Fiber structure and properties have been studied. The PVA orientation in the control and the Composite Fibers were comparable while the Composite Fiber exhibited lower crystallinity.