| 单词 | molecular sieve |
| 释义 | molecular sieve Porous crystalline substances, especially aluminosilicates, that can be dehydrated with little change in crystal structure. As they form regularly spaced cavities, they provide a high surface area for the adsorption of smaller molecules. The general formula of these substances is MnO.Al2O3.xSiO2.yH2O, where M is a metal ion and n is twice the reciprocal of its valency. Molecular sieves are used as drying agents and in the separation and purification of fluids. They can also be loaded with chemical substances, which remain separated from any reaction that is taking place around them, until they are released by heating or by displacement with a more strongly adsorbed substance. They can thus be used as cation exchange mediums and as catalysts and catalyst supports. They are also used as the stationary phase in certain types of chromatography (molecular-sieve chromatography ) |
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