Ultrafiltration polyacrylonitrile

Zhao, Z-P., Li, J., Zhang, D-X., Chen, C-X., Nanofiltration membrane prepared from polyacrylonitrile ultrafiltration membrane by low-temperature plasma, I. Graft of acrylic acid in gas, J. Membr. Sci., 232, 1, 2004. 

Ulbricht, M. and Hicke, H.G. 1993. Photomodification of ultrafiltration membranes. 1. Photochemical modification of polyacrylonitrile ultrafiltration membranes with aryl azides. 210 69-95. 

Tran, T.D., Mori, S. and Suzuki, M. 2007. Plasma modification of polyacrylonitrile ultrafiltration membrane. Thin Solid Films 515 4148-4152. 

Phenols and cyanides Polyacrylonitrile ultrafiltration membrane Agrobacterium radiobacter, Staphylococcus sciuri and Pseudomonas diminuta Kowalska eta ., 1998... 

Agarwal, G.P., Karan, R., Bharti, S., Kumar, H., Jhunjhunwala, S., Sreekrishnan, T.R. Kharul, U. (2013) Effect of foulants on arsenic refection via polyacrylonitrile ultrafiltration (UF) membrane. Desalination, 309, 243-246. 

Asatekin A, Kang S, Elimelech M et al (2007) Anti-fouling ultrafiltration membranes containing polyacrylonitrile-graft-poly(ethylene oxide) comb copolymer additives. J Membr Sci 298 136-146... 

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... 

Belfort, G. and Ulbricht, M., Surface modification of ultrafiltration membranes by low temperature plasma. I. Treatment of polyacrylonitrile, J. Appl. Polym. Sci., 56, 325, 1995. 

In cross-flow flltration, the wastewater flows under pressure at a fairly high velocity tangentially or across the filter medium. A thin layer of solids form on the surface of the medium, but the high liquid velocity keeps the layer from building up. At the same time, the liquid permeates the membrane producing a clear filtrate. Filter media may be ceramic, metal (e.g., sintered stainless steel or porous alumina), or a polymer membrane (cellulose acetate, polyamide, and polyacrylonitrile) with pores small enough to exclude most suspended particles. Examples of cross filtration are microfiltration with pore sizes ranging from 0.1 to 5 pm and ultrafiltration with pore sizes from 1 pm down to about 0,001 pm. 

Sztajer and Bryjak [48] have taken an entirely different approach to the purification of the lipase from Pseudomonas fluorescens by investigating the use of ultrafiltration capillary membranes. A two-step procedure involving continuous fractionation of the protein on polyacrylonitrile membrane followed by concentration on polysulfone membranes is suggested for continuous lipase recovery. They observe that the permeate fluxes through both membranes are similar, thereby suggesting that changing the production scales should not be difficult. 

Ultrafiltration membranes are usually asymmetric and are also made from a variety of materials but are primarily made by the phase inversion process. In the phase inversion process, a homogeneous liquid phase consisting of a polymer and a solvent is converted into a two-phase system. The polymer is precipitated as a solid phase (through a change in temperature, solvent evaporation or addition of a precipitant) and the liquid phase forms the pore system. UF membranes currently on the market are also made from a variety of materials, including polyvinylidene fluoride, polyacrylonitrile, polyethersulfone and polysulfone. 

Porous membranes can be made of polymers (polysulfones, polyacrylonitrile, polypropylene, silicones, perfluoropolymers, polyimides, polyamides, etc.), ceramics (alumina, silica, titania, zirconia, zeolites, etc.) or microporous carbons. Dense organic membranes are commonly used for molecular-scale separations involving gas and vapor mixtures, whereas the mean pore sizes of porous membranes is chosen considering the size of the species to be separated. Current membrane processes include microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), gas and vapor separation (GS), and pervaporation (PV). Figure 1 indicates the types and sizes of species typically separated by these different separation processes. 

Su, Y.-L., Cheng, W., Li, C., and Jiang, Z. 2009. Rreparation of antifouhng ultrafiltration membranes with poly(ethylene glycol)-graft-polyacrylonitrile copolymers. Journal of Membrane Science 329 246-252. 

Majeed, S., Fierro, D., Buhr, K., Wind, J., Du, B., Boschetti-de-fierro. A., and Abetz, V. 2012. Multi-walled carbon nanotubes (MWCNTs) mixed polyacrylonitrile (PAN) ultrafiltration membranes. Journal of Membrane Science 403-404 101-109. 

Permeation behavior of dextrans by charged ultrafiltration membranes of polyacrylonitrile photografted with ionic monomers. /, Appl. Polym. Sci, Vol.43, pp. 1037-1043. 

Jung, B. 2004. Preparation of hydrophilic polyacrylonitrile hlend membranes for ultrafiltration. J. Memb. Sci. 229(1-2) 129-136. 

---