Carrier surface modified hydrophilic molecular sieve membrane and preparation method thereof

Abstract

The invention provides a preparation method of a carrier surface modified hydrophilic molecular sieve membrane, which comprises the following steps: preparing a molecular sieve seed crystal in which the surface pore diameter ratio of the molecular sieve seed crystal to a porous carrier is 0.3-0.5; carrying out surface modification on the porous carrier to obtain a porous carrier with set molecularsieve seed crystal arrangement orientation; coating a molecular sieve seed crystal on the surface modified porous carrier; and carrying out secondary growth on the molecular sieve seed crystal on thesurface of the porous carrier to obtain the carrier surface modified hydrophilic molecular sieve membrane and obtain the ultrathin membrane, thereby implementing the advantages of high separation selectivity and high flux.

Description

technical field [0001] The invention relates to the field of molecular sieve membrane modification, in particular to a carrier surface modified hydrophilic molecular sieve membrane and a preparation method thereof. Background technique [0002] Pervaporation is an emerging membrane separation technology, which uses the chemical potential difference of a certain component upstream and downstream of the feed liquid membrane as the driving force to achieve mass transfer, and uses the difference in membrane affinity and mass transfer resistance for different components in the feed liquid to achieve selection. It is mainly used for dehydration or desolvation of organic solvents or water systems. Compared with traditional processes, this type of membrane separation technology has low energy consumption, less pollution, small footprint, easy operation and easy coupling with other separation processes , mild operating conditions and other advantages, can be suitable for various indu...

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Problems solved by technology

[0005] The specific content is as follows: CN200910098234A patent is synthesized by dip-coating-rolling crystal method, forming a thick film layer, and the flux of the film is not high; The density is not high; CN2013101752595A patent is synthesized by thick and fine crystal seed hot dipping-wipe coating method, which requires high temperature impregnation seed crystal, and the flux is not high; CN201410089205.1 patent uses cationic liquid to modify the support body, and then through the charge self A uniform seed layer is formed by the assembly device; and then a film layer is formed by the secondary growth method, which requires a special device to form a uniform seed layer, resulting in an increase in cost; CN201510688044.2 patent uses a low-silicon-aluminum ratio synthesis liquid to synthesize NaA molecular sieves in one step, The technical repeatability is not high; the CN201610476454.5 patent uses dopamine to modify the surface of the NaA membrane to form a modified acid-resistant membrane, which requires additional post-treatment to achieve an acid-resistant membrane; the CN201710693831.5 patent uses a negatively charged polyelectrolyte / molecular sieve composite membrane, and the procedure is complicated; CN201810178837.3 patent adopts the surface pretreatment of the support body, and the NaA seed crystal is dispersed in ethanol by drop coating, and the flux of the film formed by the secondary growth method is not high

[0006] All in all, in the existing membrane production process, there are at least one of the problems of uneven crystal coating, different scales of molecular sieve grains, unevenness of the carrier surface, and insufficient integrity and continuity of the prepared molecular sieve membrane. In addition, the permeability of the membrane Dimensions and Density Cannot Be Excellent At The Same Time

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