Filtration selection

Staff profile page - the Engineering Faculty at Loughborough. .. Broad Interests and Expertise. Compressible cake filtration Selection, scale-up and process simulation of solid/liquid separation equipment Washing and. .. http //WWW. Iboro. ac. uk/departments/eng/research/staff/html/tarleton. html [More Results From www.lboro.ac.uk]... 

ADTECHS Corporation (ADTECHS) has developed the radionuclides separation (RASEP) process for the removal and stabilization of radionuclides from liquid waste streams. The process uses filtration, selective adsorption, and electrodeposition fixation followed by cement sohdifi-cation. According to the vendor, the technology is commercially available. 

Energetic compounds can be collected for reuse by processing to reject binder, impurities, and other inert components. Explosives such as high-blast explosive (HBX), HMX, research department explosive (RDX, or hexahydro-l,3,5-trinitro-l,3,5-triazine), tetryl, TNT, NG, and NC are dissolved or suspended by steaming, high-pressure water jet cutting, or solvent extraction. Filtration, selective extraction/precipitation, vacuum evaporation, and other purification methods then separate the explosives from the binders and impurities, such as metal fragments and decomposition products. 

Parenteral drug products are required to be sterile. There are principally five different ways to sterilize a product. These are steam, dry heat, radiation, gas and filtration. Selection of which method to use is based on the product that requires sterilization. For example, protein-based drugs are heat-sensitive, so the normal means for sterilizing these products is filtration. The rationale for sterilization validation is to show the reduction in microbial load or destruction of biological indicators. 

Filtration—selective allowance or blockage of substances across a membrane, wherein movement is influenced by a pressure gradient... 

Mass transport through porous membranes can be described with the pore model. In accordance with particle filtration, selectivity is determined solely by the pore size of the membrane and the particle or the molecular size of the mixture to be separated. This process is driven by the pressure difference between the feed and permeate sides [83]. The processes described by the pore model include microfiltration and ultrafiltration. Whereas membranes for microfiltration are characterized by their real pore size, membranes for ultrafiltration are defined according to the molar mass of the smallest components retained. 

Prevention of infection hygiene, barrier nursing, air filtration, selective gut decontamination. 

Filter Selection. A variety of product- and process-related factors govern filter selection. Considerations include the characteristics of the fluid to be filtered, ie, its chemical composition and compatibiHty with the filtration system (inclusive of the membrane, filter hardware, piping, etc), the level of bioburden present, specifications on effluent quaHty, the volume of product to be filtered, flow rate, and temperature. 

In general, pan filters are selected for freely filtering soHds and thick filter cakes. Cake washing can be introduced easily. Most appHcations are in the mining and metallurgical industries for small-scale batch filtration. 

Results of test work with this filter, producing cakes of 1 mm thickness using a 3 mm clearance, have been pubUshed (33,34). The cake formed on the medium was generally stable, giving high filtration rates over long periods of time, and the precoat type cake did not blind with time. There was no evidence of any size selectivity of the process the only exception was conventional filter aids which were preferentially picked up by the rotating fluid. This... 

The white cell adsorption filter layer is typically of a nonwoven fiber design. The biomaterials of the fiber media are surface modified to obtain an optimal avidity and selectivity for the different blood cells. Materials used include polyesters, eg, poly(ethylene terephthalate) and poly(butylene terephthalate), cellulose acetate, methacrylate, polyamides, and polyacrylonitrile. Filter materials are not cell specific and do not provide for specific filtration of lymphocytes out of the blood product rather than all leukocytes. 

The older methods have been replaced by methods which require less, if any, excess sulfuric acid. For example, sulfonation of naphthalene can be carried out in tetrachloroethane solution with the stoichiometric amount of sulfur trioxide at no greater than 30°C, followed by separation of the precipitated l-naphthalenesulfonic acid the filtrate can be reused as the solvent for the next batch (14). The purification of 1-naphthalenesulfonic acid by extraction or washing the cake with 2,6-dimethyl-4-heptanone (diisobutyl ketone) or a C-1—4 alcohol has been described (15,16). The selective insoluble salt formation of 1-naphthalenesulfonic acid in the sulfonation mixture with 2,3-dimethyl aniline has been patented (17). 

Another example of manufacture in this series is the sulfonation of an aminonaphthalenesulfonic acid, followed by selected desulfonation, to make 6-amino-l,3-naphthalenedisulfonic acid (21). Thus, 2-amino-l-naphthalenesulfonic acid made by amination of 2-hydroxy-1-naphthalenesulfonic acid is added to 20 wt % oleum at ca 35°C. At this temperature, 65 wt % oleum is added and the charge is stirred for 2 h, is then slowly heated to 100°C and is maintained for 12 h to produce 6-amino-l,3,5-naphthalenetrisulfonic acid. The mass is diluted with water and maintained for 3 h at 105°C to remove the sulfo group adjacent to the amino group. After cooling to ca 20°C and filtration, 6-amino-l,3-naphthalenedisulfonic acid is obtained in 80% yield (55). 

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