Economic Beta molecular sieve membrane synthetic method

Abstract

The invention relates to an economic Beta molecular sieve membrane synthetic method. Through improvement of the current technologies, a casting solution during a crystallization process is cycled outside a synthesis kettle, reasonable arrangement of a valve can control a volume of the casting solution in a deposition kettle and the casting solution at a corresponding time segment, and based on guarantee of crystallization effect, the seed coating effect can be optimum.

Description

technical field [0001] The invention relates to a method for preparing a membrane, in particular to a method for preparing an all-silicon Beta molecular sieve membrane. Background technique [0002] Membrane separation technology is a new separation technology that emerged rapidly after the 1960s. It has the functions of separation, concentration, purification and refinement, as well as high efficiency, energy saving, environmental protection, molecular level filtration and simple filtration process, easy to control, etc. Features, which have been widely used in many fields at present, have produced huge economic and social benefits, and have become one of the most important means in today's separation science. As a kind of inorganic membrane, molecular sieve membrane has better thermal and chemical stability than organic membrane, and has great application potential in the fields of organic solvent / water separation and gas separation, while Beta molecular sieve membrane is ...

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Problems solved by technology

[0003] However, in the preparation process of the all-silicon molecular sieve membrane Beta molecular sieve membrane, in addition to crystallization into molecular sieve membranes near the carrier, other positions in the casting solution also generate molecular sieves for the crystallization process, and the molecular sieves are deposited at the bottom of the reactor. The all-silicon molecular sieve is difficult to clean with ordinary inorganic acids, such as sulfuric acid, nitric acid and hydrofluoric acid, which affects the reuse of the reactor, and the molecular sieve produced is also wasted

In the prior art, someone has used the process of crystallizing the seeded carrier to form a film and seeding the blank chip carrier in the same reactor, which avoids the damage of the reactor and the waste of molecular sieves. , but in the process of actual operation, it is found that there are many problems in this method, the most important of which is the mismatch of time

Generally, it takes at least 6 hours to crystallize the molecular sieve membrane by the secondary crystallization method, but it only takes a few seconds for general seed crystal coating such as ordinary dip coating and spin coating, even if the concentration of molecular sieve particles in the casting solution in the above method It requires a longer time than the ordinary coating process, but there is still a large difference in the time of the two processes, so when the crystallization effect of the film is guaranteed, the thickness of the molecular sieve particles deposited on the carrier to be crystallized is too thick Affect the crystallization, and when the crystallization of the molecular sieve membrane during the seeding process is guaranteed, it is seriously insufficient

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