Preparation method of stripping type hydrotalcite

Abstract

The invention discloses a preparation method of stripping type hydrotalcite. The preparation method comprises the steps of calcining commercially available or self-made hydrotalcite into in a muffle furnace to prepare layered dihydroxy composite metal oxide; adding the layered dihydroxy composite metal oxide into an organic acid salt solution by using the memory effect of hydrotalcite, performing precipitation separation, washing and vacuum drying, then putting the product into a microwave oven, and heating by using a microwave technology to ensure that hydrotalcite is stripped and a stripped hydrotalcite product is obtained. The preparation method is simple in process, easy in operation and loose in condition, and the obtained product is uniform in structure.

Description

technical field [0001] The invention relates to a preparation method of exfoliated hydrotalcite, which belongs to the field of preparation of catalytic materials. Background technique [0002] Hydrotalcite-like compounds (LDHs) are compounds formed by the accumulation of interlayer anions and positively charged laminates. The general formula of hydrotalcite chemical structure is: [M 2+ 1-x m 3+ x(OH) 2 ] x+ [(A n- ) x / n mH 2 O], where M 2+ and M 3+ are the divalent and trivalent metal cations, such as Mg, located on the host laminates, respectively 2＋ 、Ni 2+ , Zn 2+ , Mn 2+ 、Cu 2+ 、Co 2+ , Pd 2+ , Fe 2+ Equal divalent cations and Al 3+ 、Cr 3+ 、Co 3+ , Fe 3+ and other trivalent cations can form hydrotalcite; A n– It is an interlayer anion, which can include inorganic anion, organic anion, complex anion, same polyanion and heteropolyanion; x is M 3+ / (M 2+ +M 3+ ) The molar ratio is about 4:1 to 2:1; m is the number of interlayer water molecules. Its ...

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Problems solved by technology

[0004] CN101913569B discloses a simple hydrotalcite stripping method, which uses hydrogen peroxide solution as a medium, but this method can only prepare LDHs containing metals that cannot be oxidized by hydrogen peroxide, and the use has certain limitations

CN101845241A discloses a preparation method and application of exfoliated hydrotalcite. In this invention, ethylene acrylic acid random copolymer must be added to disperse LDHs with macromolecules, otherwise the material cannot be completely exfoliated, and due to the introduction of macromolecular materials, The stripped LDHs cannot be used as catalyst supports

The process conditions are harsh, time-consuming and labor-intensive, and the economic consumption is huge

In the peeling process, the simpler the interlayer anions are, the easier they are to volatilize, and the laminates are more likely to be peeled off, and it is difficult for simple ions to replace carbonate ions. Therefore, the method disclosed in CN101734679A is often incompletely exchanged when ion-exchanging pillars, making Some hydrotalcites are difficult to be stripped, and the application has certain limitations, which limits the industrial production and application of hydrotalcite stripping