Papers by Keyword: Hybrid Membrane

Abstract: This study was conducted to characterize the industrial wastewater containing Copper (II) ion and to evaluate the effect of different thickness of polysulfone as the support membrane in the fabrication of thin film composite membrane (TFC), on the removal of Copper (II) ion. From the wastewater analysis, it showed that the concentration of copper (II) ion are out of the acceptable range of Environmental Quality (Industrial Effluent) Regulations 2009. For the TFC, the polysulfone support membrane was prepared at two thicknesses, 60μm and 90μm. For each thickness, two formulations of thin layer were coated on it; i) A polymer blend of Polyvinyl Alcohol and Chitosan, and ii) Hybrid membrane as thin layer. Before undergo the treatment process, the pH of the wastewater sample was altered to 7 as the pre-treatment. The final result shows that composite membrane with hybrid membrane as thin layer with 90μm thickness of polysulfone membrane was the best membrane because it could remove 99.67% of copper (II) ion. Finally, the treated water can be discharged to the groundwater because the concentration of copper ion is less than 1 ppm, which it has fulfilled the Environmental Quality regulations. Keywords— Chitosan, Copper ion, composite membrane, hybrid membrane, industrial wastewater

Abstract: Polyvinylidene fluoride (PVDF)/PEG-POSS hybrid membrane was prepared by immersion phase separation process. The hybrid membranes were characterized by pure water flux, retention ratio to BSA, contact angle, shrinkage ratio and scanning electron microscopy (SEM). The hydrophilicity of the membrane was improved. The contact angles decreases from 82.2°to 76.3°. The shrinkage ratio decreases and the pure water flux increased when 1.0% POSS was used. Keywords: polyvinylidene fluoride (PVDF); PEG-POSS; hybrid membrane; hydrophilicity

Abstract: In this study, poly (vinylidene fluoride) (PVDF) hybrid membranes were prepared from polymeric blend of PVDF/tannic acid (TA)-Attapulgite (ATP)/PEG system via phase inversion induced by immersion precipitation in water coagulation bath. The membrane formation mechanism of PVDF/TA-ATP/PEG casting solutions in water bath thermodynamics at different temperatures and the process of membrane formation were investigated via cloud point determination and ultrasonic time-domain reflectometry (UTDR). The structures and properties of the membrane were characterized by scanning electron microscopy (SEM), and water permeation experiment, respectively. It was found that the rate of precipitation controlled by the Coagulation-Bath thermodynamics. With the coagulation temperature increasing, the gelation line was moved to non-solvent axis and the pure water flux were decreased.

Abstract: Poly (vinylidene fluoride)/attapulgite (PVDF/ATP) hybrid membrane was prepared for removal of Cr (VI) ions from wastewater with PVDF as matrix and ATP as adsorbent which was functionalized by cetyl trimethyl ammonium bromide (CTAB) and then modified by tannins (TA). The adsorption kinetics and equilibrium isotherms of the hybrid membranes were particular concerned. The results indicated that the PVDF/ATP membrane displayed a good adsorption capacity for Cr (VI) ions, the adsorption equilibrium could be established within 5 hours and the maximum adsorption capacity was 21.4 mg/g. The adsorption kinetics fit well with Lagergren second-order equation and the adsorption isotherms can be well described by Langmuir and Freundlich models.

Abstract: A series of hybrid membranes with special microstructure, based on sulfonated poly (fluorenyl ether ketone) ionomer (SPFEK, IEC=1.74 mequiv.g^-1) and secondary amine group containing SiO₂ (SiO₂–NH–NH₂), has been successfully designed and prepared for vanadium redox flow battery (VRB) application. The hybrid membranes are prepared by simply adding KH792 into the SPFEK solution in N,N’-dimethylacetamide (DMAc), followed by dispersion, co-condensation and solvent casting. The water uptake, mechanical property, proton conductivity, (VO)²⁺ permeability and single cell performance are investigated in order to understand the relationship between morphology and property of the membranes. The hybrid membranes show dramatically improved proton selectivity when compared with SPFEK. The vanadium ion (VO)²⁺ permeability through the hybrid membrane is about 10 times lower than that of virgin SPFEK. The columbic efficiency and energy efficiency of the single cell of the hybrid membrane are higher than the SPFEK membrane. The results inidicate that hybrid membranes of this type are promising for VRBs.

Abstract: Sulfonate-grafted silica/chitosan hybrid (SGSC) membrane has been successfully prepared by in-situ sol-gel method. In this method, grafting of sulfonate onto silica surface was carried out along with membrane formation. Silica sol, with the particle size of about 9 nm obtained from sodium silicate, and amido sulfonic acid were mixed with chitosan solution. The mixture was stirred for 30 minutes and aged at 60 °C for 8 hours. The results showed that sulfonate could be grafted onto the silica surface as indicated by the FTIR spectra. Silica loading is greatly affect the membrane characteristics including water retention, % swelling, and ionic conductivity. Water retention and % swelling decrease with the increase of silica loading. On the other hand, ionic conductivity and acid capacity increase with the increase of silica loading. The increase is related to the amount of silica that carries sulfonate groups. However, there is limitation on the silica loading where membrane cracked if the loading was greater than 1.5 g silica/g chitosan. The ionic conductivity and acid capacity of the membrane can take the values of about 4.2 x 10^-6 S/cm and 1.3432 meq/g, respectively.

Abstract: A series of Ti-based hybrid membranes were prepared via sol-gel reaction using tetrabutyl titanate, [Ti (OBu)₄] and tetraethyl orthosilicate (TEOS) as hybrid precursors. TGA and DSC thermal analyses revealed that these hybrid membranes have high thermal stability. Contact angle measurement shows that with an increase of Ti ingredient in hybrid membranes, their hydrophilicity decreased. The change in the surface color of sample adsorbed Cu (II) evidences that these Ti-based hybrid membranes can be used as adsorbents to adsorption separation copper (II) ions from Cu-bearing water.

Abstract: SiO₂ nanoparticles was synthesized by F127/MMA/(NH₃+H₂O)/TEOS inverse microemulsion, the formation and morphology of nanoparticles were analyzed by Ultraviolet-visible spectrum and transmission electron microscopy, and scanning electron microscope. The results showed that SiO₂ nanoparticles were spherical structure and its average particle size was about 25 nanometers. The number of SiO₂ nanoparticles in the microemulsion and hybrid membrane was increased slightly with the increase of TEOS content. However, agglomeration of SiO₂ nanoparticles appeared in the hybrid membranes at high TEOS content.

Abstract: A series of sulfonated polyphosphazene-organic montmorillonite hybrid membranes for direct methanol fuel cells (DMFCs) were prepared. The structure and characteristics of the obtained membranes were studied by testing their X-ray diffraction (XRD), water uptake, water swelling ratio, proton conductivity, thermal properties, methanol permeability and mechanical properties. The morphological analysis of the composite membranes indicated that the organic montmorillonite was uniformly distributed throughout the polymer matrix. Compared to the native sulfonated polyphosphazene membranes, the hybrid membranes showed better mechanical properties and selectivity for proton ions over methanol. The selectivity indicates that polyphosphazene-montmorillonite membranes may be promising electrolyte candidate for direct methanol fuel cells.

Abstract: AgCl Nanoparticles were synthesized in the W/O microemulsion using 2-acrylamido-2-methyl propane sulfonic acid as a surfactant, glycidyl methacrylate (GMA)/ methacrylate (MMA) mixtures as an oil phase. Then, AgCl/poly (GMA-MMA-AMPS) copolymer organic-inorganic hybrid membranes were prepared by in-situ microemulsion polymerization for separation of benzene/cyclohexane mixture. The effect of concentration of surfactant (C_AMPS) and salt (NaCl and AgNO₃) on the morphology of AgCl nanoparticles was studied by TEM. The results showed that the sizes of AgCl nanoparticles increased with salt concentration. AgCl nanoparticles maintained well dispersion in AgCl/poly (GMA-MMA-AMPS) copolymer organic-inorganic hybrid membranes. The hybrid membrane demonstrated good separation performance for benzene/cyclohexane mixtures.