Nitrogen membrane

Nitrogen membrane systems, 27 278-280 Nitrogen molecule, energy levels of,... 

Figure 8.4 The compression power used and membrane area required for nitrogen membrane production as a function of membrane selectivity. The membrane permeability used for each selectivity is taken from the Robeson upper-bound trade-offline shown in Figure 8.3. All numbers are shown relative to a membrane with a selectivity of 6 and an oxygen permeability of 0.8 Barren...

Yasuda obtained membranes with good reverse osmosis properties by polymerizing gas plasma mixtures of acetylene/water/nitrogen and acetylene/wa-ter/carbon monoxide.92 9J Elemental analysis of the acetylene/water/nitrogen membrane was not given, but it was likely approximately equivalent to the allyl-amine-derived composition. Yasuda has observed membrane performance levels as high as 99% salt rejection and 38 gfd, tested on 3.5% sodium chloride at 1,500 psi. 

Depending on the purity required, hydrogen can be further processed by cryogenic adsorption, solvent absorption, pressure swing adsorption (PSA), cryogenic absorption using liquid nitrogen, membrane separation, and metal hydride adsorption. 

Key producers for the nitrogen separation membranes are Air Products, Air Liquide and Ube. They all use either polysulfone or polyimide polymer membranes in hollow fiber configuration. Other nitrogen membrane module producers (IGS Generon systems, Parker Henifiin, Aquillo, etc.) use poly(4-methyl-l-pentene), tetrabromobisphenol polycarbonate and polyphenelyne oxide membranes. 

Filters for use in sterile gas filtration must conform to standards similar to those mandated for sterile hquid filtration. Nondestmctive integrity tests may be apphed. The tests are performed by wetting the filter with an appropriate solvent, commonly 60/40 isopropyl alcohol/water for hydrophobic membranes, and applying air or nitrogen gas at a preset pressure. 

Phospholipids. Phospholipids, components of every cell membrane, are active determinants of membrane permeabiUty. They are sources of energy, components of certain enzyme systems, and involved in Hpid transport in plasma. Because of their polar nature, phosphoUpids can act as emulsifying agents (42). The stmcture of most phosphoUpids resembles that of triglycerides except that one fatty acid radical has been replaced by a radical derived from phosphoric acid and a nitrogen base, eg, choline or serine. 

Fig. 1. Approximate economic range of nitrogen supply technologies (at median site conditions). Shaded area represents bulk liquid or PSA membrane plus...

Status of Membrane Gas Separation Technology," Nitrogen 173, 25—29 (May—June 1988). 

The chlorosilanes are clear Hquids that should be treated as strong acids. They react readily with water to form corrosive HCl gas and Hquid. Liquid chlorosilanes and their vapors are corrosive to the skin and extremely irritating to the mucous membranes of the eyes, nose, and throat. The nitrogen-functional silanes react with water to form ammonia, amines, or amides. Because ammonia and amines are moderately corrosive to the skin and very irritating to the eyes, nose, and throat, silylamines should be handled like organic amines. Trimethylsilyl trifluoromethanesulfonate and trimethylsilyl iodide form very corrosive acidic products. 

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