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Li X.,State Key Laboratory of Separation Membranes and Membrane Processes | Li J.,State Key Laboratory of Separation Membranes and Membrane Processes | Wang H.,State Key Laboratory of Separation Membranes and Membrane Processes | Huang X.,State Key Laboratory of Separation Membranes and Membrane Processes | He B.,State Key Laboratory of Separation Membranes and Membrane Processes
AIChE Journal | Year: 2015

A filtration mathematical model was developed on the basis of complete mass balance and momentum balance for the local flux distribution prediction and optimization of submerged hollow fiber membrane module. In this model, the effect of radial permeate flow on internal flow resistance was considered through a slip parameter obtained from the local flux experiments. The effects of fiber length, inside diameter, and average operating flux on local flux distribution were investigated using this model. The predicted results were in good agreement with the experimental data obtained from literature. It was also found that the asymmetry distribution of local flux could be intensified with the increase of average operating flux and fiber length, but slowed down with the increase of fiber inside diameter. Furthermore, the simulation coupled with energy consumption analysis could efficiently predict and illustrate the relationship between fiber geometry and water production efficiency. © 2015 American Institute of Chemical Engineers.


Zhang Q.,Tianjin Polytechnic University | Zhang Q.,Beijing Origin water membrane technology Co. | Lu X.,Tianjin Polytechnic University | Lu X.,State Key Laboratory of Separation Membranes and Membrane Processes | And 4 more authors.
Membranes | Year: 2016

In this study, Polyvinylidene fluoride (PVDF) hollow fiber hemodialysis membranes were prepared by non-solvent induced phase separation (NIPS) with compound addtive. The compound additive was made with polyvinyl pyrrolidone (PVP) and Poly ethylene glycol (PEG). The results showed that the modified PVDF membrane had better separation performance than virgin PVDF membrane. The UF flux of modified PVDF membrane can reach 684 L·h-1·m-2 and lysozyme (LZM) passage is 72.6% while virgin PVDF membrane is 313 L·h-1·m-2 and 53.2%. At the same time, the biocompatibility of PVDF membranes was also improved. Compared with commercial polysulfone hemodialysis membrane (Fresenius F60S membrane), the modified PVDF membrane had better mechanical and separation performance. The stress and tensile elongation of modified PVDF membrane was 0.94 MPa and 352% while Fresenius F60S membrane was 0.79 MPa and 59%. The LZM passage reached 72.6% while Fresenius F60S membrane was 54.4%. It was proven that the modified PVDF membrane showed better hydrophilicity, antithrombogenicity, less BSA adsorption, and lower hemolytic ratio and adhesion of platelets. Water contact angle and BSA adsorption of the modified PVDF membrane are 38° and 45 mg/m2 while Fresenius F60S membrane are 64° and 235 mg/m2. Prothrombin time (PT) and activated partial thromboplastin time (APTT) of the modified PVDF membrane are 56.5 s and 25.8 s while Fresenius F60S membrane is 35.7 s and 16.6 s. However, further biocompatibility evaluation is needed to obtain a more comprehensive conclusion. © 2016 by the authors; licensee MDPI, Basel, Switzerland.


Hu M.,Tianjin Polytechnic University | Kang W.,Tianjin Polytechnic University | Kang W.,State Key Laboratory of Separation Membranes and Membrane Processes | Cheng B.,Tianjin Polytechnic University | And 4 more authors.
Microchimica Acta | Year: 2016

A highly sensitive and fast sensor for gaseous hydrogen chloride (HCl) is described. It is based on the use of the optical probe 5,10,15,20-tetraphenylporphyrin contained in a poly(lactic acid) nanoporous fiber membrane that was fabricated via electrospinning. With its porous structure, the sensor overcomes the slow gas absorption and diffusion of other sensing materials. Field emission SEM was employed to characterize the morphology of the sensing membrane. The exposure to HCl gas causes a color change from pink to green that is due to the protonation of the central nitrogen atoms of the porphyrin, and fluorescence is quenched. The largest increase in absorbance occurs at 442 nm. HCl gas can be detected in this way even at sub-ppm levels. The detection limit is 34 ppb, and the response time is as short as 5 s. The sensor is highly stable after ten cycles of tracing HCl gas and recovery, and response is fully reversible. [Figure not available: see fulltext.] © 2016, Springer-Verlag Wien.


Li F.,Tianjin Polytechnic University | Kang W.,Tianjin Polytechnic University | Kang W.,State Key Laboratory of Separation Membranes and Membrane Processes | Cheng B.,Tianjin Polytechnic University | And 2 more authors.
Catalysis Communications | Year: 2015

A novel carbon nanofiber containing silver nanoparticles (NPs) with hollow structure was fabricated via co-electrospinning and in situ reduction. The hollow structure avoided the waste of silver NPs embedded in the nanofibers while ensuring high specific surface area. The formation of silver NPs was confirmed by Field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The catalytic behavior of the nanofibers obtained to the reduction of methylene blue with NaBH4 was tracked by UV-visible spectroscopy. The results showed that carbon nanofibers containing silver NPs with hollow structure possessed significant catalytic properties. © 2015 Elsevier B.V. All rights reserved.


Zhang Y.,Tianjin Polytechnic University | Zhang Y.,State Key Laboratory of Separation Membranes and Membrane Processes | Wang L.,State Key Laboratory of Separation Membranes and Membrane Processes | Wang L.,Tianjin Polytechnic University | And 2 more authors.
Nano-Structures and Nano-Objects | Year: 2016

Well-defined three-dimensional (3D) hierarchical flowerlike calcium molybdate (CaMoO4) microspheres were successfully synthesized via a facile ultrasound-assisted ethylenediaminetetraacetic acid (EDTA) chelation process. The structure and morphology were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). Time-dependent experiments with appropriate intervals have clearly disclosed that the self-assembly process of 3D flowerlike CaMoO4 microspheres is governed by a nucleation-dissolution-recrystallization growth mechanism. Moreover, the nitrogen adsorption-desorption isotherm indicated the presence of mesoporosity in the product. The room temperature photoluminescence (PL) properties of the products were then studied using a spectrophotometer and the samples exhibited green emission peaks centered around 470 nm, 485 nm and 493 nm with 280 nm excitation wavelength. © 2016 Elsevier B.V. All rights reserved.


Kang W.,Tianjin Polytechnic University | Li F.,Tianjin Polytechnic University | Zhao Y.,State Key Laboratory of Separation Membranes and Membrane Processes | Qiao C.,Tianjin Polytechnic University | And 2 more authors.
RSC Advances | Year: 2016

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. © The Royal Society of Chemistry 2016.


Wang W.,Tianjin Polytechnic University | Wang W.,State Key Laboratory of Separation Membranes and Membrane Processes | Zhang J.,Tianjin Polytechnic University | Zhang Y.-F.,Tianjin Polytechnic University | Zhang Y.-F.,State Key Laboratory of Separation Membranes and Membrane Processes
Acta Polymerica Sinica | Year: 2016

With hydroxyl multi-walled carbon nanotubes (MWCNTs-OH) as carbonous fillers the high performance PVDF hollow fiber ultrafiltration membranes modified by MWCNTs-OH were prepared by the nonsolvent induced phase inversion process. Adding MWCNTs-OH into N, N-dimethyl acetamide (DMAC) solvent with ultrasonic treatment could strengthen their dispersion, and produce uniform casting membrane solution. The morphology and performances of modified membranes were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic contact angle (DCA) and mechanical properties tests. The effects of MWCNTs-OH on the water flux and rejection as well as mechanical properties of the resulted hollow fiber membranes were investigated. The results showed that the water flux increased from 376. 4 L/m2h to 510. 9 L/m2h, while the rejection stabilized around 95. 0% as the MWCNTs-OH loading increased from 0 to 0. 09 wt%. The tensile strength and elongation at break increased from 1. 68 to 2. 42 MPa and 44. 18% to 79. 18%, respectively. The SEM and TEM images indicated that MWCNTs-OH were easy to reunite in the matrix along with the increase of contents of MWCNTs over 0. 09 wt%, resulting in the decrease of the membrane tensile strength and water flux. The crystal form of the hollow fiber membranes changed little with the addition of MWCNTs-OH which was evidenced by the analysis of Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction.


Tao L.,State Key Laboratory of Separation Membranes and Membrane Processes | Zhao Y.,State Key Laboratory of Separation Membranes and Membrane Processes | Kang W.,State Key Laboratory of Separation Membranes and Membrane Processes | Cheng B.,State Key Laboratory of Separation Membranes and Membrane Processes | Qiao C.,State Key Laboratory of Separation Membranes and Membrane Processes
Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society | Year: 2016

Polytetrafluoroethylene (PTFE) nanofibers were prepared by an electrostatic spinning technology. Titanium dioxide (TiO2) particles were loaded on the PTFE nanofibers via dipping and sintering. The morphology and structure of the photocatalyst film were characterized. Effects of reacting conditions of the TiO2/PTFE superfine-fiber film on the photocatalytic degradation of methylene blue under UV-Vis light irradiation were investigated. In addition, the recycling utilization of load type TiO2 light catalyst was also discussed. The result show that the TiO2(as anatase)/PTFE nanofiber photocatalyst film was obtained after calcination at 450℃. Under the violet light (300 W, 365 nm) irradiation, when irradiation distance is 30 cm and after irradiation for 55 min, the TiO2/PTFE superfine-fiber film is prepared by dipping for 5 h. Its degradation rate for methylene blue with initial concentration of 5 mg/L and volume of 100 mL is 99%. The degradation efficiency of methylene blue is still 46% after recycling for 5 times, indicating that the recycling utilization rate is greater. © 2016, Editorial Department of Journal of the Chinese Ceramic Society. All right reserved.

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