Filtration resistances, membrane technology

Union Carbide went one step further-sintering the hydrous Zr(IV) oxide dynamic membrane in place on a porous carbon tube at elevated temperatures. This resulted in a high-temperature (300°F) inorganic membrane which is resistant to a pH of 1-14. Further, the membrane may be cleaned with organic solvents that would dissolve conventional polymer membranes. This technology was subsequently licensed to SFEC (Societe de Fabrication d Elements Cata-lytiques) in Bollene, France and to Gaston County Filtration Systems in Stanley, NC. 

UF and MF have been successfully employed in analytical chemistry. The principal factors that should be considered for analytical and technological use of membranes with aqueous media are the pore size and pore size distribution, solution flow, and degree of hydrophilicity. The solution flow (flux) through an MF or UF membrane is given by the equation J = P/ R, where / is the solution flux, R is a phenomenological resistance coefficient, and P is the transmembrane pressure drop. A pump or a gas (e.g., nitrogen) bottle can be used as a pressure source (50-500 kPa). The other main features of the filtration system are a membrane filtration unit and reservoirs. 

Since selective formation of a specified pore size has been achieved at a considerable level in the present membrane preparation technology, one important key to further extend spread of the membrane filtration in the fumre is economic efficiency. The key to increase the economic efficiency will be reduction of clogging and increasing mechanical and chemical strength. In this coimeclion, a membrane superior in thermal resistance is advantageous because it can expand the range of application. In the field of pharmaceutical application, for example, steam sterilization resistance may be required. 

However, we have succeeded in the development of ozone-resistant filtration modules by developing PVDF hollow-fiber membranes and potting materials having a high resistance to ozone, and assembling technology (Mori et al., 1998). 

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