Fouling surface modification

Grebenyuk, V.D., Chebotareva, R.D., Peters, S., andLinkov, V. 1998. Surface modification of anion-exchange electrodialysis membranes to enhance anti-fouling characteristics. Desalination 115,... 

In addition to fluid dynamics, surface modification of the membrane can reduce the attractive forces or even create repulsive ones between potential fouling solutes and the membrane (Belfort, Davis, and Zydney, 1994). 

Combined surface modification and management of fluid dynamics at the membrane surface are effective tools for fouling avoidance. 

Peters S. Surface modification of electro-dialysis membranes to enhance anti-fouling characteristics. PhD dissertation. University of the Western Cape, Cape Town, South Africa, 2000. 

The major concern in respect of surface modification is the integrity and resistance to erosion. It could be a serious problem if cracks or local peeling occur that might facilitate localized corrosion or the buildup of deposits. It has to be remembered also that the presence of a film or coating on the heat exchanger surfaces could be regarded as a fouling layer that by itself imposes a resistance to heat transmission. 

Changes in cross-flow velocity or transmembrane pressure cannot always alleviate fouling. Membranes made from hydrophilic polymers like cellulose acetate are generally less prone to fouling than the hydrophobic polymers. However, cellulose acetate is limited in its tolerance to high or low pH, organic solvents and elevated temperature. In some cases, surface modification of the more chemically-resistant polymers has rendered them less susceptible to fouling. 

Wavhal DS and Fisher ER, Membrane surface modification by plasma-induced polymerization of acrylamide for improved surface properties and reduced protein fouling, Langmuir 2003,19, 79-85. 

The incorporation of positive charges has decreased the fouling susceptibility of membranes even more effectively. This is the principle of the aromatic polyamide membrane series commercialized by Hydranautics as low fouling composite membranes (LFC). Cationic charge-modified nylon membranes are also commercially available from CUNO 3M, under the trademark Zeta Plus . Pall Corp. sells cationic charge-modified nylon membranes under the trademark Ngg Posidyne. There are different ways to make the membrane positively charged. A patent from Millipore [148] describes the surface modification of hydrophobic membranes by contacting them with a solution of polyamine epichlorohydrin... 

Zhou, Y., Yu, S., Gao, C. and Feng, X. 2009. Surface modification of thin composite polyamide membranes by electrostatic self-deposition of polycations for improved fouling resistance. Sep. Purif. Technol. 66 287-294. 

Reduction of Membrane Fouling by Polymer Surface Modification... 

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