separation of gases will be done depending upon their
(a) freezing point
(b)melting point
(c)boiling point
(d)pressure
Answers
Answer:
Explanation:
Boiling point is that answer
Answer:
boiling point
Explanation:
Gas separation in membranes takes place due to differences in transport of the different species flowing through the membrane itself. Both porous1 inorganic and dense polymeric membranes can be used as selective gas separation barriers, but most of the membranes used in gas separation are made of polymers, like cellulose derivatives, polysulfone, polyimides and polyamides. Depending on the pore size, gas transport in inorganic membranes may occur via different mechanisms. Figure 3.7 illustrates some of the different mechanisms of gas permeation through porous and dense membranes.
With large pores – from 0.1 to 10 μm – gases permeate the membrane by convective flow (and no separation occurs). This is the case of permeation through macroporous membranes. Vice versa, mesoporosity takes into account the collisions of the molecules with the pore walls, which are more frequent than the collisions among molecules and so the molecular diffusion is predominant. In this case, the mean free path of the gas molecules is greater than the pore size. Such a mesoporous membrane is a conglomerate of capillarities, large and small, straight and tortuous; diffusion is governed by the Knudsen mechanism and, in accordance with kinetic theory, the transport rate of any gas is inversely proportional to the square root of its molecular weight (Graham’s law of diffusion). Finally, if the membrane pores are extremely small (< 2 nm), then gases are separated, for example, by molecular sieving. The transport in these membranes is very complex and involves diffusion in the gas phase and (single or multilayer) surface diffusion that occurs when the permeating species exhibit a strong affinity for the membrane surface and adsorb along the pore walls.