Membrane systems design cellulose acetate

Like evaporators, RO works on most plating baths and rinse tanks. Most RO systems consist of a housing that contains a membrane and feed pump. There are four basic membrane designs plate-and-frame, spiral-wound, tubular, and hollow-fiber. The most common types of membrane materials are cellulose acetate, polyether/amide, and polysulfones.29... 

Applications for FT-30 membrane have appeared in all reverse osmosis fields from seawater desalination to home tapwater systems operating on line pressure. At this date, it is the only commercial reverse osmosis membrane other than cellulose acetate that has specific FDA approval for food contact usage.63 Versions of this membrane, manufactured under license to FilmTec, are available in tubular form (ZF-99, Patterson Candy International) and plate-and-frame design (HR-95, HR-98, De Danske Sukkerfabrikker).64 65... 

In studies to remove organic fouling on RO membranes, it has been reported that several commercial cleaners developed by Pfizer gave excellent results. Differential pressure of the membrane system could be reduced by 42% using a neutral pH liquid formulation (Floclean 107) designed to remove organics, silt, and other particulates from cellulose acetate RO membranes. For polyamide, polysulfone, and thin-film-composite... 

Matson et al. ( ) designed a flow system for measurements of HjS permeability through ILMs at temperatures of 363-403 K and total feed pressures of 2.1 10 kPa. The ILM consisted of a 30 wt. < KjCO, aqueous solution immobilized in microporous cellulose acetate and polyether sulfone films. The feed gas, a mixture of H S, COx, and N2 was humidified and sent to a temperature controlled membrane cell. A helium sweep gas was similarly humidified and served to carry the permeating gases to analysis by gas chromatography. 

Membrane life is an important factor affecting process economics. Membranes typically require replacement every three to seven years. It is therefore necessary to consider factors that may shorten or possibly extend their life. Funk et al. (1986) investigated the effect of impurities in the gas on a cellulose acetate membrane in acid gas service. They found that various components in the gas affect the permeability, the tensile strength, and the elastic modulus of the membrane. Some of the adverse effects of individual components can be mitigated by proper design (e.g., temperature control), but other impurities may require removal prior to membrane processing. Therefore, the feed gas should be evaluated for the presence of particulates, entrained liquids, oil mist (compressors), condensible components, all trace compounds, and water. Pretreatment systems that may be needed include ... 

D-glucose and the three-enzyme system GOx, mutarotase and invertase for sucrose estimation. A common format was adopted to facihtate design and operation, in this case immobilization method, the fact that all enzymes used were oxidases and that a common detection principle, reoxidation of H2O2 generated product, was chosen (except for ascorbic acid which was estimated directly). Pectin, a natural polysaccharide present in plant cells, was used as a novel matrix to enhance enzyme entrapment and stabilization in the sensors. Interferences related to electrochemi-caUy active compounds present in fruits under study were significantly reduced by inclusion of a suitable cellulose acetate membrane diffusional barrier or by enzymatic inactivation with ascorbate oxidase. Enzyme sensors demonstrated expected response with respect to their substrates, on analyte average concentration of 5 mM. 

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