Molecular sieve doped with transition metal and preparation method and application of molecular sieve

Abstract

The invention provides a molecular sieve doped with transition metal and a preparation method and application of the molecular sieve. The molecular sieve has a RHO molecular sieve configuration, and comprises a chemical composition of X2O3:aYO2:bZO:cMdeltaO at a molar ratio, wherein Y is a tetravalent element, X is a trivalent element, Z is a transition metal element, and M is a monovalent or multi-valent cation. The molecular sieve is synthesized through hydrothermal treatment on initial gel which is prepared from crown ether, sodium, cesium, water, a silicon source, an aluminum source or a boron source and transition metal. Since the framework of the molecular sieve is doped with a part of transition metal elements, a large amount of CO2 can be preferentially adsorbed during separation of CO2 and CH4, a large amount of CH4 can be preferentially adsorbed during separation of CH4 and N2, and a large amount of CO2 can be preferentially adsorbed during separation of CO2 and N2; and whenthe molecular sieve is applied to a tail gas treatment process, the reduction activity of nitrogen oxides can reach 90% or above at a low temperature through the molecular sieve.

Description

technical field [0001] The invention belongs to the field of gas separation adsorbents, and in particular relates to a molecular sieve doped with a transition metal and a preparation method and application thereof. Background technique [0002] Global warming has become the most concerned environmental issue at present. CO 2 It is the main product of fossil energy combustion and one of the main sources of the greenhouse effect. According to statistics, in the past few decades, due to the massive combustion of fossil energy, CO 2 China's emissions are increasing at an average annual rate of 80%. CH 4 is a unit equivalent greenhouse effect ratio of CO 2 More serious greenhouse gases, which cause about 30% of environmental pressure, while natural gas is also considered a promising clean energy alternative to coal and oil, CH 4 As the main component of natural gas, it needs to be recovered. In many cases, the gas mixture often contains a large amount of N 2 , and due to ...

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Problems solved by technology

Wright et al. used the same method to synthesize RHO molecular sieves with a SAR value of 9 and applied them to CO in flue gas. 2 removed, but RHO molecular sieves were found to neutralize CO 2 The site of action is mainly alkali metal cations, so the heat of adsorption is still very large, resulting in difficult regeneration (J.Am.Chem.Soc., 2012, 134, 17628-17642; Chem.Mater., 2014, 26, 2052- 2061)

Patent CN105452168A synthesized a RHO molecular sieve with a SAR value greater than 9.5 by adjusting the composition of the hydrogel and applied it to the purification of exhaust gas such as automobile exhaust, but its reactivity below 200°C was still not high, indicating that Cu in the catalyst 2+ Decentralization method needs further improvement

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