129809647221617500_476Development history and status of carbon membrane: membrane separation technology, is considered to be one of the most promising high-tech 21st century.
It played a strategic role in the industrial technology, to upgrade traditional industry plays a key role. Polymer organic polymer base carbon film is developing in the thermal stability test. Mid mid 50 to 60 of the last century, PVC, And poly vinyl chloride, polyvinyl alcohol, charring and glass such as polyacrylonitrile carbon come out one after another, their unique structure and performance, suggesting that the group development of such materials to the whole development of carbon science has a far-reaching impact. 70 released mid polyimide (PI) by heat treatment capable of forming high product of graphitization degree study. After the 80 's, on the internationalIn looking for conductive performance long-term does not variable and high temperature stability of conductive sexual polymer material boom in the has gradually reported has from poly evil II effect (POD) film preparation high quality of graphite film, to poly benzene pole Asia vinyl base (PPV) film start system graphite film and from on bit poly benzene pole (PPP), and poly naphthalene pole (PN) and poly anthracene (PA) start by heat treatment system carbon film of research knotThe fruit. These are aerospace, electronic and chemical industry development, urgent need for heat transfer of high temperature resistance, corrosion resistance, and good electrical conductivity, relative density of synthetic material are inseparable. Carbon-carbon membrane for membrane separation mechanism of liquid phase separation mechanism mainly through porous filter and ultra-filtration, carbon gas through the mechanism of the film has the following four types: Knudsen diffusion, capillary condensation, surface diffusion, molecular sieveMin. Knudsen gas through the mechanism of a diffusion: when you pore size much smaller than the molecular free path, molecular diffusion in a film dominated by Knudsen diffusion, Knudsen diffusion is based on the quality of different molecular diffusion, its isolation coefficient with the molecular mass is inversely proportional to the square root of
TERA Gold, based on the low carbon membrane separation mechanism of selective and limited in theory, so it's not wide range of use, onlyApply to a small number of large molecular weight difference of gas separation, separation of H2 and CO2,O2,N2.
Damle,et al in porous graphite coating on resin of furfural, carbonization, preparation of a carbon membrane, in which H2, N2, Knudsen diffusion separation, separation factor of only 3.8. B capillary condensation: mixed gas of one or severalSelective condensation of gases in film hole, the condensation of gases by diffusion across the membrane hole, because this component within the hole together, hindered by other components, this condensed component together with no separation of the components to.
This mechanism requires a medium of film hole holes, this separation mechanism is mainly used in condensate gas separation of components. C surface-diffusion: mixingOne or more of the gas adsorbed on the surface of the membrane hole better, faster than not adsorbed component diffusion of such components, mixed-gas separation, separation effect mainly decided by the selective adsorption of gas mixture components. Because the surface diffusion of adsorbed gas quickly, at the same time, is no adsorption of gas molecules by molecular adsorption impede Knudsen diffusion through membrane, increasing the total separation of selectiveSo, mixed gas surface diffusion in a membrane separation in carbon, carbon film can at the same time have a high selectivity and high permeability. Rao and Sircar graphite for making support, coated on poly-vinyl chloride-acrylate LaTeX, charcoal produced the "selective surface" of carbon membrane, in which hydrocarbons or gas adsorption in carbon membrane permeability of CO2 than the H2, hPenetration of e, applied from the hydrocarbons and hydrogen separation of a mixture of hydrocarbons, C4H10 H2 separation factor of up to 94, and hydrogen separation and enrichment. D molecular sieve: based on molecular sieving carbon membranes based on known as molecular sieving carbon membranes, it requires a membrane aperture for the molecular size, basic principles of molecular sieve is smaller in diameterThrough the film, and closure of large molecules are in diameter. Carbon molecular sieve membrane has a high degree of selectivity, the oxygen-nitrogen separation factor of up to 10 per cent, and inorganic membrane separation of oxygen and nitrogen coefficient near 1.
With externally bonded CFRP, preparation of phenolic resin-based carbon molecular sieve membrane for separation of oxygen and nitrogen coefficient of 10.84 and isolation coefficient of hydrogen, nitrogen is almost 60. The actual process gasesSeparation mechanism of carbon membrane for separation is often the above mixture of several mechanisms. Preparation of carbon films: technological conditions for preparation of carbon membrane and its control is the key to a stable and excellent coating properties of membrane structures techniques. Preparation of carbon films from its route can be divided into the following three steps: 1, carbonization processes: carbonization process conducted in a vacuum or inert atmosphere conditions. As the temperatureRise of, precursor of various groups, such as free radicals, heterocyclic polymerization of decomposition, porosity development, expansion and contraction of the aperture. Carbonization processes such as CH4, CO, H2O
SWTOR Credits, CO2, H2, precipitation of small molecular substances
Diablo 3 power leveling, makes on the substrate with holes for gas separation. Heating rate, temperature and temperature on carbonMembrane separation performance of a greater influence. 2, carbon deposits: sedimentary can be divided into the gas phase and liquid phase carbon deposits. On the support plate, CH4 and organic steam by physical or chemical methods such as benzene can form a dense layer of membrane.
While immersion in liquid phase can also be used, such as sol-gel coating, made with better separation efficiency of carbon membrane. 3, the activation process:In order to improve the permeability of carbon membrane, are necessary to activate the carbon film to open its closed hole. Activation of carbon membrane gas activation and activation of drugs can be used. Oxidation of CO 2, steam, micro-air as medium, some carbon dioxide in carbon film erosion into the hole, but there are chemical substances (n aOH, KM nO 4, HNO 3) Activated carbon film. In summary, using a simple procedure or method of preparation of good performance of carbon membrane more difficult, so using a variety of methods or steps in the preparation, can control its pore size distribution and separation performance.
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