Membrane poly sulfone

The most extensive studies of plasma-polymerized membranes were performed in the 1970s and early 1980s by Yasuda, who tried to develop high-performance reverse osmosis membranes by depositing plasma films onto microporous poly-sulfone films [60,61]. More recently other workers have studied the gas permeability of plasma-polymerized films. For example, Stancell and Spencer [62] were able to obtain a gas separation plasma membrane with a hydrogen/methane selectivity of almost 300, and Kawakami et al. [63] have reported plasma membranes... 

The single-ion conductor, PAGSOa Na (m/n = 0.4 or 1.0, in which m and n are the number of siloxy units in the structure), was made by consecutive hydrosilylation of PHMS with AM PEG and allyl glycidyl ether. The neutral polymer was sulfonated with aqueous NaHSOa, which quantitatively converted the epoxy group into -CH(0H)CH2S03". Excess NaHSOa was removed by repeated ultrafiltration of the polymer solution with a cutoff membrane having a Mw of 1000. The poly sulfonate was azeotropically dried with benzene and finally in vacuum at 50 °C for several days. 

The maximum pore size used to separate phospholipid micelles, in which color pigments and other impurities are physically bound, can be in the range of 10,000-50,000 Da depending on the polymer type. Considerable swelling occurs with poly-sulfone membranes, which, in turn, affects the membrane chemistry drastically and reduces flow rates and in some cases totally closes the pores. Similar results have also been observed with polyamide and fluorinated polymers. 

Membrane bioreactor Asymmetric poly-sulfone membrane Diffusion of carbohydrates in liquid-filled pores Enzymatic hydrolysis of lactose Whole cells of Sutfolobus solfataricus entrapped in the tube wall 65... 

Kaeselev, B., Pieracci, J., and Belfort, G., Photoinduced grafting of ultrafiltration membranes Comparison of poly(ether sulfone) and poly(sulfone), J. Membr. Sci., 194, 245, 2001. 

Several types of three-phase hoUow-fiber (I lb) modules have been described. They can be classified into two groups. The first one with paraUel phase flow is developed by Sirkar group, termed as a hoUow-fiber contained hquid membrane and described in detaU in Ref [4], Another types ot HF module, developed by Schlosser s group, hoUow-fibers in tube pertractor with paraUel flow [10, 11, 23-26, 90, 101] consists of one or two intermixed U-shaped bundles of microporous polypropylene fibers, inserted into poly-sulfon (or glass) tubes (see Fig. 5.11). For better nfixing, pulsation of the LM phase along the fibers is used. It increases the transport rate by 35-60%. 

Ethylene has been separated from ethane by a silver nitrate solution passing countercurrent in a hollow fiber poly-sulfone.165 This separation has also been performed with the silver nitrate solution between two sheets of a polysilox-ane.166 A hydrated silver ion-exchanged Nafion film separated 1,5-hexadiene from 1-hexene with separation factors of 50-80.167 Polyethylene, graft-polymerized with acrylic acid, then converted to its silver salt, favored isobutylene over isobutane by a factor of 10. Olefins, such as ethylene, can be separated from paraffins by electroinduced facilitated transport using a Nafion membrane containing copper ions and platinum.168 A carbon molecular sieve made by pyrolysis of a polyimide, followed by enlargement of the pores with water at 400 C selected propylene over propane with an a-valve greater than 100 at 35°C.169... 

Some oxidoreductases require expensive cofactors, such as NADH. This requires continuous regeneration of the cofactor in a separate enzymatic reaction using a sacrificial substrate. Nanofiltration membranes have been used to separate the two enzyme systems.256 A sulfonated poly-sulfone nanofiltration was used in the reduction of fructose to mannitol, using glucose to gluconolactone to regenerate the NADH. 

In the fall of 1966, researchers at North Star Research Institute began a search for compression-resistant microporous substrates.19 This effort resulted in the development of microporous sheets of polycarbonate (Lexan) and poly-sulfone (Udel).20 Figure 5.4 shows a graph comparing the flux levels and flux stability for three membranes made at that time (a) float-cast cellulose acetate on microporous polysulfone, (b) float-cast cellulose acetate on a mixed cellulose ester microfilter support and (c) a standard asymmetric cellulose acetate membrane. The improvement in membrane fluxes was readily apparent, when switching from cellulosic substrates to the microporous polysulfone substrate. 

Figure 5.11 SEM photographs of the surface texture of composite polyamide membranes from aliphatic and aromatic amines (a) uncoated microporous poly-sulfone (b) polyamide from polyethylenimine and trimesoyl chloride (c) tri-ethylenetetramine and trimesoyl chloride (d) 1,3-benzenediamine and trimesoyl chloride (e) 2,4-toluenediamine and trimesoyl chloride (f) 4-methoxy-1,3-benzenediamine and trimesoyl chloride. Note the smooth surface for aliphatic amine-based interfacial trimesamides and the coarse ridge-and-valley structure for aromatic amine-based interfacial trimesamides.

Asymmetric phase-inversion membranes like the membranes employed in reverse osmosis are difficult to prepare as gas permeation is much more sensitive to micropores than RO due to the much higher diffusion coefficients of gases. For the same reason, the composite membrane differs from RO composite membranes in gas permeation, the top layer of the asymmetric support structure is responsible for the separation while it is the sole duty of the coating to plug the micropores. Consequently, the material of the coating chosen (silicone) has a high permeability but a low selectivity while the membrane material (poly-sulfone) has a high selectivity (and a much lower permeability). 

Figure 3.5 Effect of membrane composition on electrical conductivity and transport number of cation exchange membrane prepared by the paste method. (O, O) transport number ( , ) specific conductivity. DVB divinylbenzene St styrene PVC poly(vinyl chloride). Composition DVB/(St + DVB) — 0.1 (by weight) numbers in the figure are DOP/PVC (DOP dioctyl phthalate -additives) (by weight). The copolymer membrane is sulfonated with concentrated sulfuric acid.

G.N. Richard, Ion-exchange membranes by sulfonation of poly(vinylidene fluoride) films. J. Appl. Polym. Sci., 1964, 8, 2269-228. 

Y. Dai, X. Jian, S. Zhang, and M. D. Guiver. Thermostable ultrafiltration and nanoflltration membranes from sulfonated poly(phthalazinone ether sulfone ketone). J. Membr. ScL, 188(2) 195-203, July 2001. 

Another method of preparing nanofiltration membranes is to dip-coat a thin layer of sulfonated poly(phenylene oxide) (SPPO) [17], sulfonated polysulfone (SPS) [18], or carboxylated polysulfone [19] on a porous substrate membrane. The sulfonic acid groups in SPPO and SPS also become negatively charged with -SO3 groups upon dissociation. Sulfonic acid is a stronger acid than carboxylic acid. 

S. Chowdhury, P. Kumar, P.K. Bhattacharya, A. Kumar, Separation characteristics of modified poly-sulfone ultrafiltration membranes using NO,, Sep. Purif. Technol. 24 (2001) 271—282. 

The acid-base Nafion composite membranes include blends of Nafion with polypyrrole (PPy) [98-104], polybenzimidazole (PBI) [105-107], poly (propyleneoxide) (PPO) [108, 109], polyfurfuryl alcohol (PFA) [110], poly(vinyl alcohol) (PVA) [111-115], sulfonated phenol-formaldehyde (sPF) [116], polyvinylidene fluoride (PVdF) [117-122], poly(p-phenylene vinylene) (PPV) [123], poly(vinyl pyrrolidone) (PVP) [124] polyanifine (PANI) [125-128], polyethylene (PE) [129], poly(ethylene-terephtalate) [130], sulfated p-cyclodextrin (sCD) [131], sulfonated poly(ether ether ketone) (sPEEK) [132-135], sulfonated poly(aryl ether ketone) (sPAEK) [136], poly(arylene ether sulfone) (PAES) [137], poly(vinylimidazole) (PVl) [138], poly(vinyl pyridine) (PVPy) [139], poly (tetrafluoroethylene) (PTFE) [140-142], poly(fluorinated ethylene-propylene) [143], sulfonated polyhedral oligomeric silsesquioxane (sPOSS) [144], poly (3,4-ethylenedioxythiophene) (PEDT) [145, 146], polyrotaxanes (PR) [147], purple membrane [148], sulfonated polystyrene (PSSA) [149, 150], polystyrene-b-poly(ethylene-ran-butylene)-bpolystyrene (SEES) [151], poly(2-acrylamido-2-methyl-l-propanesulphonic acid-co-l,6-hexanediol propoxylate diacrylate-co-ethyl methacrylate) (AMPS) [152], and chitosan [31]. A binary PVA/chitosan [153] and a ternary Nafion composite with PVA, polyimide (PI) and 8-trimethoxy silylpropyl glycerin ether-1,3,6-pyrenetrisulfonic acid (TSPS) has also been reported [154]. 

Yang T (2009) Composite membrane of sulfonated poly(ether ether ketone)and sulfated poly (vinyl alcohol) for use in direct methanol fuel cells. J Membr Sci 342 221-226... 

Choi J, Kim DH, Kim HK, Shin C, Kim SC (2008) Polymer blend membranes of sulfonated poly(arylene ether ketone) for direct methanol fuel cells. J Membr Sci 310 384-392... 

Jiang Z, Zhao X, Manthiram A (2013) Sulfonated poly(ether ether ketone) membranes with sulfonated graphene oxide fillers for direct methanol fuel cells, bit J Hydrogen Energ 38 5875-5884... 

Norris BC, Li W, Lee E, Manthiram A, Bielawski CW (2010) Click-functonalization of poly (sulfone)s and a study of their utilities as proton conductive membranes in direct methanol fuel cells. Polymer 51 5352-5358... 

Chapter 6 deals with the description of different membranes used in direct alcohol fuel cells. Firstly, the properties of Nafion and its inorganic and organic composites are analyzed, focused on the proton cmiductivity and alcohol permeability, which determine the alcohol selectivity of the modified Nafion membranes. Then, a number of alternative non-fluorinated proton conducting membranes, including sulfonated polyimides, poly(arylene ether)s, polysulfones, poly(vinyl alcohol), polystyrenes, and acid-doped polybenzimidazoles, are described in relation to their selectivity in comparison to Nafion. The chapter includes a comprehensive summary of the relative selectivity of these membranes and their performance in direct alcohol fuel cells. Anion exchange membranes for alkaline direct alcohol fuel cells are also reviewed. 

Bhattacharya R, Phaniraj TN, Shailaja D. Poly-sulfone and polyvinyl pyrrolidone blend membranes with reverse phase morphology as controlled release systems experimental and theoretical studies. J Membr Sci 2003 227(l-2) 23-37. 

PAI and Ti02 nanoparticle impregnated poly-(sulfone) nanofiltration membranes with an integral dense layer have been prepared by a phase inversion technique from a dope solution of A-methyl-2-pyrroli-done and 1,4-dioxane as solvents [85]. The low... 

KUduff, J.E., Mattaraj, S., Pieracci, J.P. and Belfort, G. 2000. Photochemical modification of poly(ether sulfone) and sulfonated poly(sulfone) nanofiltration membranes for control of fouhng by natural organic matter. Q jj linali 132 133-142. 

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