Membrane filtration membranes

Membrane filtration Membrane module Membrane permeability Membrane process Membrane processes Membrane reactor Membrane roofing Membranes... 

Membrane Filtration. Membrane filtration describes a number of weU-known processes including reverse osmosis, ultrafiltration, nanofiltration, microfiltration, and electro dialysis. The basic principle behind this technology is the use of a driving force (electricity or pressure) to filter... 

MEMBRANE FILTRATION. Membrane filter cartridges are seldom used in fruit juice technology, as hot-filling is the common practice and prior membrane filtration is therefore unnecessary. These filters can only be used after fine filtration, as otherwise the membrane is immediately clogged up. 

K.W. Lawrence, N.K. Shammas, M. Cheryan, Z. Yu-Ming, Z. Shuai-Wen, Treatment of food industry foods and wastes by membrane filtration. Membrane and Desalination Technologies 2008, 13, 237-269. 

Membrane filtration Membrane separation processes use semipermeable membranes to separate impurities from water. The membranes are selectively permeable to water and certain solutes. A driving force is used to force the water to pass through the membrane, leaving the impurities behind as a concentrate. The amount and type of material removed depends upon the type... 

Heating 30 min 100 °C (over boiling water) + membrane filtration Membrane filtration <0.2 pm Sterile solution of excipients Sterile solution of excipients -... 

CNT membranes membrane membrane filtration membrane types... 

Methods to Detect and Quantitate Viral Agents in Fluids. In order to assess the effectiveness of membrane filtration the abihty to quantitate the amount of vims present pre- and post-filtration is critical. There are a number of techniques used. The method of choice for filter challenge studies is the plaque assay which utilizes the formation of plaques, localized areas in the cell monolayer where cell death caused by viral infection in the cell has occurred on the cell monolayer. Each plaque represents the presence of a single infectious vims. Vims quantity in a sample can be determined by serial dilution until the number of plaques can be accurately counted. The effectiveness of viral removal may be determined, as in the case of bacterial removal, by comparing the vims concentration in the input suspension to the concentration of vims in the effluent. 

T. D. Brock, Membrane Filtration, Sci. Tech. Inc. Publishing, Madison, Wis., 1983. 

Membrane filtration has been used in the laboratory for over a century. The earliest membranes were homogeneous stmctures of purified coUagen or 2ein. The first synthetic membranes were nitrocellulose (collodion) cast from ether in the 1850s. By the early 1900s, standard graded nitrocellulose membranes were commercially available (1). Their utihty was limited to laboratory research because of low transport rates and susceptibiUty to internal plugging. They did, however, serve a useflil role in the separation and purification of coUoids, proteins, blood sera, enzymes, toxins, bacteria, and vimses (2). 

The individual membrane filtration processes are defined chiefly by pore size although there is some overlap. The smallest membrane pore size is used in reverse osmosis (0.0005—0.002 microns), followed by nanofiltration (0.001—0.01 microns), ultrafHtration (0.002—0.1 microns), and microfiltration (0.1—1.0 microns). Electro dialysis uses electric current to transport ionic species across a membrane. Micro- and ultrafHtration rely on pore size for material separation, reverse osmosis on pore size and diffusion, and electro dialysis on diffusion. Separation efficiency does not reach 100% for any of these membrane processes. For example, when used to desalinate—soften water for industrial processes, the concentrated salt stream (reject) from reverse osmosis can be 20% of the total flow. These concentrated, yet stiH dilute streams, may require additional treatment or special disposal methods. 

Medical uses for Udel resin include surgical trays, nebulizers, flow controllers for blood, and respiration regulators. Transportation applications center around automotive fuse housings, electrical connectors, and switches. Electrical and electronic end uses include coil bobbins, housings, connectors, bushings, capacitor film, and business machine parts. EinaHy, water, heater dip tubes, milking machine parts, pollution control equipment, and some filtration membranes are made. 

Once an undesirable material is created, the most widely used approach to exhaust emission control is the appHcation of add-on control devices (6). Eor organic vapors, these devices can be one of two types, combustion or capture. AppHcable combustion devices include thermal iaciaerators (qv), ie, rotary kilns, Hquid injection combusters, fixed hearths, and uidi2ed-bed combustors catalytic oxidi2ation devices flares or boilers/process heaters. Primary appHcable capture devices include condensers, adsorbers, and absorbers, although such techniques as precipitation and membrane filtration ate finding increased appHcation. A comparison of the primary control alternatives is shown in Table 1 (see also Absorption Adsorption Membrane technology). 

Optimized modern dry scrubbing systems for incinerator gas cleaning are much more effective (and expensive) than their counterparts used so far for utility boiler flue gas cleaning. Brinckman and Maresca [ASME Med. Waste Symp. (1992)] describe the use of dry hydrated lime or sodium bicarbonate injection followed by membrane filtration as preferred treatment technology for control of acid gas and particulate matter emissions from modular medical waste incinerators, which have especially high dioxin emissions. 

Polymer Membranes These are used in filtration applications for fine-particle separations such as microfiltration and ultrafiltration (clarification involving the removal of l- Im and smaller particles). The membranes are made from a variety of materials, the commonest being cellulose acetates and polyamides. Membrane filtration, discussed in Sec. 22, has been well covered by Porter (in Schweitzer, op. cit., sec. 2.1). 

Process Description Microfiltration (MF) separates particles from true solutions, be they liquid or gas phase. Alone among the membrane processes, microfiltration may be accomplished without the use of a membrane. The usual materi s retained by a microfiltra-tion membrane range in size from several [Lm down to 0.2 [Lm. At the low end of this spectrum, very large soluble macromolecules are retained by a microfilter. Bacteria and other microorganisms are a particularly important class of particles retained by MF membranes. Among membrane processes, dead-end filtration is uniquely common to MF, but cross-flow configurations are often used. 

Economics Microfiltratiou may be the triumph of the Lilliputians nonetheless, there are a few large-industrial applications. Dextrose plants are veiy large, and as membrane filtration displaces the precoat filters now standard in the industry, very large membrane microfiltratiou equipment will be built. 

---