Method for preparing modified and formed magnesium-aluminum layered double hydroxides

Abstract

The invention discloses a method for preparing modified layered magnesium aluminum hydroxide. The preparation process is chemical modification and drying molding: 1) The powder layered magnesium aluminum hydroxide with stable performance (denoted as Mg- AlLDH) and binder are added to the magnesium salt solution with a certain concentration to make it reach a certain solid-liquid ratio, adjust the pH value of the solution, and after a certain period of reaction, centrifuge the obtained mixture to obtain a solid part; 2) to obtain a solid substance , use a catalyst molding machine to make a cylindrical adsorbent, dry it at a certain temperature, and then roast it at a high temperature to obtain a modified layered magnesium aluminum hydroxide. The layered magnesium aluminum oxide obtained in the present invention has the characteristics of high efficiency and low consumption, and solves the problem that the solid suspended matter existing in the existing layered magnesium aluminum oxide adsorbent during use is easy to block the bed body, it is difficult to separate after the reaction, and regeneration cannot be realized In order to solve the deficiencies and shortcomings of the invention, a method for preparing modified layered magnesium aluminum hydroxide is provided.

Description

technical field [0001] The invention belongs to the field of fine chemical industry, in particular to a preparation method of modified and shaped layered magnesium aluminum hydroxide. Background technique [0002] Layered magnesium aluminum hydroxide (Mg / Al Layered Double Hydroxide, LDHs) is a new type of inorganic functional material with special structure and properties. Typical molecular formula is MgA1 3 (OH) 16 CO 3 4H 2 O, its surface is alkaline, has a unique layered structure, the layers are connected by weak chemical bonds (hydrogen bonds), and have exchangeable anions. Calcination at a certain temperature can destroy the layered structure of LDHs and form a stable composite metal oxide with a larger average specific surface area and average pore volume than the precursor. The layered magnesium aluminum hydroxide in the calcined state has a structural "memory" effect, which can reabsorb water and anions in the water environment to restore the layered structure ...

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Problems solved by technology

[0004] However, the current research and application of layered magnesium aluminum hydroxide is mainly limited to the powder form, and there are deficiencies such as solid suspended solids are easy to block the bed, difficult to separate after reaction, and regeneration cannot be achieved. Therefore, layered magnesium aluminum hydroxide is in practical application. Therefore, in order to realize the practical application of layered magnesium aluminum hydroxide in adsorption and ion exchange, effective shaping and modification of layered magnesium aluminum hydroxide must be carried out.