Ceramic microfiltration

In addition, bacterias need to be removed from well, river or lake water before water can be rendered potable. A properly selected microfiltration ceramic membrane is effective for bacteria decontamination. When used preceding a reverse osmosis or an ion-exchange unit, the microflltiaiion membrane protects the downstream separation process from bacteria contamination and possible fouling due to colloids. 

Separation of manufactured sohds from process liquids and recycling of these liquids (water or organic solvents) is an interesting way to valorize by-products and to minimize the production of liquid effluents in a number of industries. Microfiltration ceramic membranes have been aheady used for the recovery of particles in the ceramic industry and in drilling operations, of pigments in paint and ink industries, and have potential applications in a wide variety of liquid-solid separation... 

Mourouzidis-Mourouzis, S.A. and Karabelas, A.J., Whey protein fouling of microfiltration ceramic membranes— pressure effects, J. Membr. Sci., 282, 124, 2006. 

Mercury porosimetry is a well-adapted method to characterize the pore size and pore size distributions of microfiltration ceramic membranes. In this method,... 

H. Zhu, X. Wen, and X. Huang, Characterization of membrane fouling in a microfiltration ceramic membrane system treating secondary effluent, Desalination 284 (2012) 324-331. 

Ceramic, Metal, and Liquid Membranes. The discussion so far implies that membrane materials are organic polymers and, in fact, the vast majority of membranes used commercially are polymer based. However, interest in membranes formed from less conventional materials has increased. Ceramic membranes, a special class of microporous membranes, are being used in ultrafHtration and microfiltration appHcations, for which solvent resistance and thermal stabHity are required. Dense metal membranes, particularly palladium membranes, are being considered for the separation of hydrogen from gas mixtures, and supported or emulsified Hquid films are being developed for coupled and facHitated transport processes. 

Ceramic Membranes Alumina-based microfiltration membranes and porous carbon substrates are tightened for use as UF membranes usually by depositing a layer of zirconium oxide on the surface. 

Large Plants The economics of microfiltration units costing about ilO " is treated under ultrafiltration. When ceramic membranes are used, the cost optimum may shift energy consumption upward to as much as 10 kWh/m. ... 

A significant recent advance has been the development of microfiltration and ultrafiltration membranes composed of inorganic oxide materials. These are presently produced by two main techniques (a) deposition of colloidal metal oxide on to a supporting material such as carbon, and (b) as purely ceramic materials by high temperature sintering of spray-dried oxide microspheres. Other innovative production techniques lead to the... 

In the early 1980s, former employees of Euroceral founded a small company located near Montpellier in France known as Ceram-Filtre. The rather less well-known Ceram-Filtre membranes comprise a multichannel support with 19 channels of 4 mm diameter and a microfiltration membrane made of an oxide. 

Cot, L., C. Guizard and A. Larbot. 1988. Novel ceramic material for liquid separation process Present and prospective applications in microfiltration and ultrafiltration. Industrial Ceramics 8(3) 143-48. 

Terpstra, R. A., B. C. Bonekamp and H. J. Veringa. 1988. Preparation, characterization and some properties of tubular alpha alumina ceramic membranes for microfiltration and as a support for ultrafiltration and gas separation membranes. Desalination 70 395-404. 

Porous metals have long been commercially available for particulate filtration. They have been used in some cases as microfiltration membranes that can withstand harsh environments, or as porous supports for dynamic membranes. Stainless steel is by far the most widely used porous metal membrane. Other materials include silver, nickel. Monel, Hastelloy and Inconel. Their recommended maximum operating temperatures range from 200 to 650°C. Elepending on the pore diameter which varies from 0.2 to 5 microns, the water permeability of these symmetric membranes can exceed 3000 L/h-m -bar and is similar to that obtained with asymmetric ceramic microfiltration membranes. Due to the relatively high costs of these membranes, their use for microfiltration has not been widespread. 

Gillot, J. and D. Garccra. 1984. New ceramic filter media for cross-flow microfiltration and ultrafiltration. Paper presented at Filtra 84 Conference, 2-4 October 1984, Paris. 

Membralox ceramic tubular microfiltration modules produced - 1985... 

The fermentation of S. paucimobilis SC 16113 culture was carried out in a 750-liter fermentor. From each fermentation batch, about 60 kg of wet cell paste was collected. Cells harvested from the fermentor were used to conduct the biotransformation in 1-, 10-, and 210-liter preparative batches under aerobic or anaerobic conditions. The cells were suspended in 80 mM potassium phosphate buffer (pH 6.0) to 20% (w/v, wet cells) concentration. Compound (6) (1-2 g/ liter) and glucose (25 g/liter) were added to the fermentor and the reduction reaction was carried out at 37°C. In some batches, at the end of the fermentation cycle, the cells were concentrated sevenfold by ceramic crossflow microfiltration using a 0.2-pm filter, diafiltered using 10 mM potassium phosphate buffer (pH 7.0), and used directly in the bioreduction process. In all batches of biotransformation, the reaction yield of >85% and the e.e. of >98% were obtained (Table 4). The isolation of compound (7) from the 210-liter preparative batch was carried out to obtain 100 g of product (7). The isolated (7) gave 83% chemical purity and an e.e. of 99.5%. 

Metal oxides, used for manufacturing of ceramic nanofiltration membranes, are intrinsically hydrophilic. This limits the use of these membranes to polar solvents filtration of nonpolar solvents (n-hexane, toluene, cyclohexane) usually yields zero fluxes. Attempts have been made to modify the pore structure by adding hydrophobic groups, for example, in a silane coupling reaction [38, 43]. This approach is similar to modifications of ultrafiltration and microfiltration membranes... 

Microfiltration membranes usually have a nominal pore diameter in the range of 0.1-10 pm. However, the membrane specification is not an absolute parameter. The membranes usually present a pore size distribution around the nominal value and the shape of the bioparticles can determine whether they are retained or pass through the membrane. The membranes are manufactured from polymers, such as Teflon, polyester, PVC (polyvinyl chloride), Nylon, polypropylene, polyethersulfone, and cellulose, or from inorganic materials, such as ceramic and sinterized stainless steel. 

Improvement of membrane separation technology has resulted in the isolation of MFGM-enriched material from commercially available products. A phospholipid-rich fraction can be extracted from whey (Boyd et al., 1999) and buttermilk (Sachedva and Buchheim, 1997) with a reported yield of 0.25 g of phospholipids/g of protein in buttermilk (Sachdeva and Buchheim, 1997). Microfiltration of whey derived from the Cheddar cheese process, using 0.2 pm ceramic filters results in a fraction containing two major phospholipids, phosphatidylcholine and phosphatidylethanolamine, and lesser amounts of phosphatidylinositol, phosphatidylserine, sphingomyelin and cerebrosides (Boyd et al., 1999). The phospholipid fraction separated from the total lipids contains a larger proportion of mono- and polyunsaturated fatty acids (mainly oleic, Cig i and linoleic, C ) compared to the total lipid and the neutral lipid fraction (Boyd et al., 1999). 

Cross-flow filtration is also referred to as tangential flow filtration or microfiltration, but all three terms refer to a process by which membranes are used to separate components in a liquid solution (or suspension) on the basis of their size. The development of robust membranes in polymeric and ceramic materials has provided a powerful new technology for bioseparations, which is already widespread in the process industries as well as for water treatment processes. 

Microfiltration units can be configured as plate and frame flat sheet equipment, hollow fiber bundles, or spiral wound modules. The membranes are typically made of synthetic polymers such as Polyethersulfone (PES), Polyamide, Polypropylene, or cellulosic mats. Alternate materials include ceramics, stainless steel, and carbon. Each of these come with its own set of advantages and disadvantages. For instance, ceramic membranes are often recommended for the filtration of larger particles such as cells because of the wider lumen of the channels. However, it has been shown that spiral wound units can also be used for this purpose, provided appropriate spacers are used. 

We wish to concentrate and achieve a solvent switch for a solution by batch crossflow micro filtration. The flux, jv, for the ceramic microfiltration membrane is 10 gal/(h-ft2). The initial solution volume is 1800 gal the final volume is 360 gal. The amount of protein present is 18.0 kg, and the molecular weight is 1,213.43 g/mole. The pressure drop is 30 psi (essentially 2 atm) and the operating temperature is 277 K. Calculate the area, A, required to complete the filtration in 2 h. 

Ceramic membranes are quite important since microporous ceramics are the principal barrier in UFe separation. Similar devices are used for microfiltration membranes and to a lesser extent for ultrafiltration. Homogeneous films are transformed into microporous devices by irradiation followed by selective leaching of the radiation damaged tracks, by stretching (Cortex is one welldmown example), or by electrochemical attack on aluminum. A few membranes are made by selective leaching of one component from a solid, as in membranes derived from glass or by selective extraction of polymer blends. 

For microfiltration applications, pore diameters of ceramic membranes in the range of 0.1 to 10 im arc typical These membranes can be prepared by dip or spin coating of... 

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