Filter membrane, fiber removal from

Membrane filters are used to remove particulates from samples and solvents prior to HPLC analysis and also for the preparation of liquid samples, where no solvent is used. Typical materials of construction for membrane filters are usually synthetic polymeric materials, although natural substances, such as cellulose, and inorganic materials, such as glass fibers, are also used acryhc... 

Silt density index (SDl) is a sensitive method for determining the ability of a filter to remove colloidal particles 14). SDl (in min ) is used extensively as a criterion in minimizing fouling of reverse osmosis membranes. The lower the SDl value, the cleaner is the stream. Manufacturers of reverse osmosis membranes recommend that the stream be prefiltered so that it has an SDl factor less than 3.0. Typically 1 pm absolnte 6) filters have an SDl of about 4-5. Manufacturers of hallow fiber membrane filters claim SDI s in the range of 1.75 to 2.25. SDl measurements of effluents from the nano alumina media range from 0.5-1.0. The SDl of 32% PAC media was measured and found to be about 1.0. Turbidity as well as SDl tests have confirmed that the extent of shedding of PAC particles into effluent streams is minimal. 

Measurement of dissolved mercury compounds requires removal of particulate materials from the sample by either filtration or centrifugation. Various types of filters can be employed 0.45 pm membrane filters (precipitation, seawater), disposable polystyrene units (Nalgene) with nitrocellulose membrane filters, and pretreated glass fiber filters. 

Mass Transfer Efficiency. Information about molecular transport and delivery, known as mass transfer efficiency, has been applied to separation and secretion functions of artificial organs. In hemodialysis, toxins are removed from circulating blood that passes through a filter called a dialyzer. This process also removes excess salts and water to maintain a healthy blood pressure. The dialyzer is composed of a semipermeable membrane or cylinder of hollow synthetic fibers that separates out the metabolic-waste solutes in the incoming blood... 

This method was first devised for use with membrane filters but we have recently found it practicable to use glass filters if these are first hardened by igniting them. Great care is needed to ensure that the filter is not frayed or fibers removed when it is handled by forceps. Because there is very little trouble from hygroscopicity with glass filters and no complications from electrostatic effects, their use is attractive. 

Depth filtration is often the first type of filtration a wine sees after fermentation when the wine is pushed through a thick layer of pads made from cellulose fibers, diatomaceous earth or perlite which traps the particles and can be removed from the wine. If the producers wish to further filter the wine, they may go to surface filtration. Surface filtration involves running the wine along a thin film of polymer material filled with holes tinier than the particles that are being filtered out. Running the wine parallel to filter surface (known as "Cross-flow" surface filtration) will minimizing the amount of potential clogging of the filter. Most membranes are made from plastic or ceramic. 

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