Membrane fouling hydrophilic membranes resistance

The hemocompatibility of hydrophilic materials is relevant for standard blood-contacting medical devices, but there are additional applications for which the protein-resistant properties are useful. Hydrophilic materials play a large role in the membrane industry, where improved wet-out improves solution flow through the membrane additionally, hydrophilic membranes show less protein fouling (55). In the realm of engineering thermoplastics, low protein binding materials are useful in lab equipment and in biopharmaceutical applications... 

Most of today s ultrafiltration membranes are made by variations of the Loeb-Sourirajan process. A limited number of materials are used, primarily polyacrylonitrile, poly(vinyl chloride)-polyacrylonitrile copolymers, polysulfone, poly(ether sulfone), poly(vinylidene fluoride), some aromatic polyamides, and cellulose acetate. In general, the more hydrophilic membranes are more fouling-resistant than the completely hydrophobic materials. For this reason water-soluble... 

Hydrophobic membranes attracted a thicker irreversible adsorption layer than hydrophilic membranes [127, 128]. Hydrophilic membranes display low sorptivity for fouling macrosolutes such as proteins. In some situations, ionically charged membranes are more fouling-resistant than electroneutral membranes. The apparent high fouling-resistance of ceramic (alumina) membranes is worthy of special note, although the explanation of this... 

A composite ceramic membrane was formed [77] by the graft polymerisation of a hydrophilic polymer, PVP, onto the surface of silica membranes (pore size = 3.0 pm). The flux of an unmodified UF membrane of an oil/water emulsion (4.7%) decreased with time as compared to the flux of the composite membrane. The dechne in flux was caused by fouling and/or the immediate formation of an oil gel layer on the surface of the unmodified membrane. The modified membrane, in contrast, was not only more resistant to adsorption of oil, but also had a higher oil rejection. The performance of the modified ceramic membrane depends upon the configuration of the grafted chains in response to solvent—polymer interactions. Thus, the hydrophific PVP polymer chains tend to expand or extend away from the surface in aqueous solutions, preventing oil adsorption on the membrane surface. Simultaneously, the hydrophific polymer allows the passage of water molecules preferentially over oil. 

MF of E. coli suspensions a neutral hydrophilic membrane surface was less susceptible to fouling than charged (positively or negatively) membranes (Kochkodan et al. 2006) MF of E. coli suspensions the modified membranes were more resistant to biofouling the number of bacterial cells able to proliferate from countable colonies was reduced for qDMAEM-grafted samples compared with unmodified membranes (Hilal et al. 2003, 2004)... 

A similar approach was used for the in situ preparation of NF PE8 membranes containing hydrophilic functional groups such as 8O3H, COOH, or C(= 0)NH2 [75]. Testing the modified and unmodified membranes over a period of 30 days demonstrated that surface-modified composite membranes have better fouling-resistance characteristics. In the case of the unmodified membranes, the flux decreased from 41.65 to 19.21 1/m h, whereas for the surface-modified membranes under similar conditions, the flux reduced from 46.75 to 31.62 Fm%. However, in the case of NF... 

Maartens et al. [15] characterized adsorbed foulants calorimetrically and concluded that foulants in pulp and paper mill effluents are phenolic and hydrophobic in nature, a result corroborated by Puro et al. [9]. Maartens et al. also modified their membranes to make them more hydrophilic and achieved less fouling and better cleaning efficiency. Thus, pretreatment or modification of a membrane can improve its fouling resistance, its flux or retention, and can enhance its usability in pulp and paper industry applications [16]. 

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