Article

The Art of Surface Modification of Synthetic Polymeric Membranes

Journal of Applied Polymer Science (Impact Factor: 1.64). 01/2010; 115(2). DOI: 10.1002/app.31108

ABSTRACT The development in the area of surface modification of polymeric synthetic membranes since 2000 is reviewed. Many patents, articles, and reviews have been written on the development in the area of surface modifi-cation of polymeric synthetic membranes subjected to RO, UF, NF, gas separation (GS), and biomedical applications, mainly since 2000, but recently more attention has been given to the modification of their surfaces to obtain desira-ble results. In particular, most emphasis has been given to plasma treatment, grafting of polymers on the surface, and modifying the surfaces by adding SMMs (surface-modify-ing molecules). New additives are synthesized to make the polymeric membrane surfaces either to be more hydro-philic or hydrophobic, aimed at improvement in selectivity and permeability of the membranes for GS, NF, and RO. Improvement in antifouling by surface modification is also a popular topic in the membrane industries. In the last 8 years, tremendous research efforts have been made on the development of antifouling membranes. V C 2009 Wiley Peri-odicals, Inc. J Appl Polym Sci 115: 855–895, 2010

2 Followers
 · 
645 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Blending selected polymer materials in the membrane fabrication process has been widely investigated for dense film membrane in order to improve the membrane gas separation performance. However, such a strategy has not been fully explored on hollow fiber membrane, which is preferred in industry for gas separation. In this study, Matrimid® 5218 hollow fibers with 0–12 wt% additive (PEG or PEO–PDMS copolymer) were fabricated via phase inversion technique. The effects of additives on the hollow fiber׳s gas transport properties were discussed in terms of the membrane morphology and surface composition, gas separation performance as well as plasticization and aging property. Both additives showed significant impact on the membrane structure, particularly influencing the skin layer of the hollow fiber. However, the copolymer also displayed surface aggregation behavior which resulted in the modification of skin layer composition. The increase in the concentration of PEG improved the CO2 permeance from 21 GPU (without PEG) to 37 GPU (with 12 wt% PEG) and the hollow fibers with 12 wt% PEO–PDMS copolymer displayed a doubled CO2/N2 selectivity compared to the fibers without the additive. Addition of PEG reduced the CO2 plasticization pressure while PEO–PDMS improved the plasticization resistance of hollow fibers.
    Journal of Membrane Science 10/2014; 468:107–117. DOI:10.1016/j.memsci.2014.05.024 · 4.91 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A membrane separation was introduced to treat the lignocellulose hydrolysate from the production of bio-ethanol in order to reuse the enzymes and reduce product inhibition. To handle the severe problem of membrane fouling in this type of feed, which results in lowered membrane permeances, the recently developed magnetically induced membrane vibration filtration (MMV) system was applied in a submerged configuration using four different commercial ultrafiltration membranes. The results indicated that membrane surface hydrophilic modifications could not really prevent fouling; on the other hand, vibration enhanced filtration was proved to be an efficient way to improve membrane performance via preventing or limiting of fouling, especially at higher vibration amplitudes and for more dilute feeds.
    Journal of Membrane Science 02/2014; 452:165–170. DOI:10.1016/j.memsci.2013.10.045 · 4.91 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The characterization of nanofiltration (NF) membranes is necessary for predicting their performance under different operating conditions, and for optimizing the membrane-separation process. A thin-film composite (TFC) polymer membrane for nanofiltration, modified with tri- and tetra-alkoxysilanes, was produced using a sol–gel procedure. The surface charges of the modified membranes were determined at different pHs by means of the zeta-potential. The streaming current was measured for a zeta-potential analysis of the flat-sheet membranes. Knowledge of the zeta-potential is essential for designing and operating membrane processes, and its measurement provides the key to understanding the control of charge-related phenomena. The zeta-potential of modified membranes is distinct from that of an untreated membrane. The isoelectric point was found to be at a higher pH after a treatment with any of the alkoxysilanes. The surfaces of the modified membranes showed an amphoteric behaviour. The homogeneity and stability of the treatment were assessed by a repeated zeta-potential analysis of the same and different membrane samples.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 04/2013; 422:110–117. DOI:10.1016/j.colsurfa.2013.01.005 · 2.35 Impact Factor