Membranes ultrafiltration

A fuU listing of aU U.S. patents issued between Febmary 1970 through Febmary 1981 is given in Reference 26. Similar related material on membranes, ultrafiltration, and reverse osmosis can be found in References 46—49. 

Ultra filtration. This process removes macromolecules, microorganisms, particulate matter, and pyrogens using a thin, selectively permeable membrane. Ultrafiltration caimot remove ions from water and is generally employed as a polishing process. 

Membrane Ultrafiltration Membrane ultrafiltration is often one of the favored unit operations used for the isolation and concentration of biomolecules because they can be easily scaled up to process large feed volumes at low costs. Toward the end of an ultrafiltration operation, additional water or buffer is added to facilitate the passage of... 

The Bioscience Division supplies reagents, kits and other enabling technologies and products for R D in life science. The majority of the product line is based on microp-orous membrane, ultrafiltration, and chromatographic technologies. 

Filtration, 11 321-397 75 824—825. See also Filter cycles Filter performance Filters Microfiltration Nanofiltration membranes Ultrafiltration as advanced wastewater treatment, 25 908-909... 

Blatt, W. F., Dravid, A., Michaels, A. S. and Nelson, L. In Membrane Science and Technology, Flinn, J. E. (ed.) (Plenum, New York, 1970). Solute polarisation and cake formation in membrane ultrafiltration Causes, consequences and control techniques. 

Porter, M. C. Ind. Eng. Chem. Prod. Res. Develop, 11 (1972) 234. Concentration polarisation with membrane ultrafiltration. 

W5. Windisch, R. M., and Bracken, M. M., Cerebrospinal fluid proteins Concentration by membrane ultrafiltration and fractionation by electrophoresis on cellulose acetate. Clin. Cherru 16,416-419 (1970). 

The single-chain RIPs are generally more stable to a wider range of experimental conditions than ricin A chain However, loss of material can occur in the course of procedures based on selective passage through membranes. Ultrafiltration may be performed using a membrane with a lower Mr cut-off. 

In addition to equipment used in the actual fractionation processes, a variety of other items are needed. In particular it should be possible to change buffers quickly and to concentrate protein solutions with ease. These operations require such things as dialysis membranes, ultrafiltration cells, and gel-exclusion columns of various sizes. 

Because of the challenging environment in which ultrafiltration membranes are operated and the regular cleaning cycles, membrane lifetime is significantly shorter than that of reverse osmosis membranes. Ultrafiltration module lifetimes are rarely more than 2-3 years, and modules may be replaced annually in cheese whey or electrocoat paint applications. In contrast, reverse osmosis membranes are normally not cleaned more than once or twice per year and can last 4-5 years. 

Although whey protein products have several food uses, the lactose contained in the permeate is less valuable, and many plants discharge the permeate to a biological wastewater treatment plant. A few plants recover lactose as dry lactose sugar, as shown in Figure 6.23. Some plants also ferment the lactose concentrate to make ethanol. An introduction to membrane ultrafiltration in cheese production is given by Kosikowski [26],... 

Sometimes the surfactants used for cleaning in manufacturing processes create undesirable O/W emulsions. This can be difficult to deal with since emulsification is usually an important aspect of a cleaning process. If the process or the detergent formulation cannot be adjusted to prevent the undesirable emulsion formation then a separate demulsification/separation step may be needed. In some cases these emulsions can be broken by separating out and concentrating the dispersed phase, such as by membrane ultrafiltration [454],... 

Cellulase Retention and Sugar Removal by Membrane Ultrafiltration During Lignocellulosic Biomass Hydrolysis... 

Figure 6.18 Schematic of the polyvinyl alcohol reclaim process by inorganic membrane ultrafiltration [adapted from Gaston County, 1976J...

Concentration of lignosulfonates (LS) and reduction of sugars (S) in residual black liquors from chemical pulp production by ceramic membrane ultrafiltration... 

Blatt, W.F. et al.. Solute polarizahon and cake formation in membrane ultrafiltration. Causes, consequences, and control techniques, in Membrane Science and Technology, J.E. Flinn (Ed.), pp. 47-97. Plenum Press, New York, 1970. 

Source Adapted from Pressurized ozone membrane ultrafiltration/nanofiltration methodology for TDS removal in the paper mill process water for energy saving, production efficiency, and environmental benefits. Available at http /www.recycle.com/linpac-nice3/documents/doefinalreport.pdf. 

The waters in question are pumped to a membrane bioreactor equipped with an air injection system, where part of the feed is recycled, making it move across a membrane ultrafiltration system, to prevent the presence of suspended microelements in the later phase of reverse osmosis. From the ultrafiltration process, two streams are obtained a concentrated stream of salts and microbial mass, which is recycled to the bioreactor, and a permeate stream that passes to the reverse osmosis plant. 

As has been described above, HA is an essential functional component of almost all tissues in the vertebrate organism. Thus, various animal tissues - e.g. rooster combs, shark skin, bovine eyeballs - have been used as sources of isolation and production of high molar mass HAs. Since in the biological materials HA is usually present in a complex linked to other biopolymers, several separation procedures have to be applied in order to obtain a pure compound, such as protease digestion, HA ion-pair precipitation (with e.g. cetylpyridinium chloride), membrane ultrafiltration, HA non-solvent precipitation and/or lyophilization [135,136]. The mean molar mass of the commercially available extractive HA preparations obtained from animal tissues is mostly in the range from several hundred thousands Da up to approximately 2.5 MDa. To date, the demand for HA materials approved for applications in human medicine has been satisfied by high molar mass HAs prepared from the rooster combs. For example, Healon (Pharmacia Upjohn, Inc., Peapack, NJ, USA) - used in viscosurgery at eye implant insertion - has a mean HA molar mass of about 2.5 MDa. 

Reference intervals for free testosterone and percent free testosterone in serum are listed in. Table 53-6 and in Chapter 5 261,336 q jjggg concentrations compare favorably with those obtained when using membrane ultrafiltration and gel filtration methods. Equilibrium dialysis is considered die reference method for determining free testosterone in serum. 

Most problems with this procedure have involved tracer impurities and the separation of bound and free labeled fractions. Several separation techniques have been used, including equilibrium dialysis, membrane ultrafiltration, and steady-state gel filtration. Their deficiencies include a requirement for a large sample volume, the need for complicated correction of sample volume changes that occur during the separation, and difficulties of collecting and measuring radioactivity in numerous fractions of each sample. Equilibrium dialysis has been used most often in the past, but serious errors often arise from the sample dilution required by this method. Symmetrical dialysis of undiluted samples is reported to be less susceptible to tracer contamination and dilution effects. Ultrafiltration also appears to overcome these problems and to obviate errors caused by dilution. 

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