Method for synthesizing A type molecular sieve membrane at low temperature

A molecular sieve and low-temperature technology, applied in the field of membrane separation, can solve problems such as high temperature, achieve the effects of reducing film thickness, good synthesis repeatability, and reducing defects

Active Publication Date: 2019-07-05
SHANGHAI UNIV OF ENG SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But this patent still needs to adopt higher temperature in the process of preparing molecular sieve membrane

Method used

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  • Method for synthesizing A type molecular sieve membrane at low temperature
  • Method for synthesizing A type molecular sieve membrane at low temperature
  • Method for synthesizing A type molecular sieve membrane at low temperature

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Synthesis of type A molecular sieve membrane, hydrothermal crystallization at 25°C for 6 days

[0038] Step 1: Synthesis of A-type molecular sieve seed crystals: the mother liquor formula of A-type molecular sieve seed crystals is 6Na 2 O:0.55Al 2 o 3 :1.0SiO22 :150H 2 O (molar ratio), the silicon source is silica sol, and the aluminum source is sodium metaaluminate. Hydrothermal synthesis was carried out at room temperature for 7 days to obtain type A molecular sieve seed crystals. The seeds were centrifuged, washed with deionized water, and dried for later use. The SEM image of the seed crystal, such as Figure 1-2 As shown, the seed crystal is a cubic crystal of 50-300 nm. The XRD pattern of the seed crystal is as image 3 As shown, it is a pure type A molecular sieve without miscellaneous crystals.

[0039] Step 2: Select a porous ceramic tube (made of alumina) with a pore size of 100nm as the carrier, seal the two ends of the carrier with glaze, wash and dr...

Embodiment 2

[0049] Synthesis of type A molecular sieve membrane, hydrothermal crystallization at 25°C for 8 days

[0050] Example 2 is basically the same as Example 1, the only difference is that the crystallization time is 8 days.

[0051] The water / ethanol pervaporation separation test results of type A molecular sieve membrane tubes are shown in Table 2.

[0052] The water / ethanol pervaporation separation test result of table 2 embodiment 2

[0053]

[0054] Note: Separation temperature is 70°C, feed 5wt% water: 95wt% ethanol

Embodiment 3

[0056] Synthesis of type A molecular sieve membrane, hydrothermal crystallization at 25°C for 10 days

[0057] Example 3 is basically the same as Example 1, the only difference is that the crystallization time is 10 days.

[0058] The water / ethanol pervaporation separation test results of type A molecular sieve membrane tubes are shown in Table 3.

[0059] The water / ethanol pervaporation separation test result of table 3 embodiment 3

[0060]

[0061] Note: The separation temperature is 70°C, and the feed is 10wt% water: 90wt% ethanol.

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Abstract

The invention relates to a method for synthesizing an A type molecular sieve membrane at a low temperature. The method comprises the following steps: crystallizing a silicon source, an aluminum source, an alkali and water to prepare an A type molecular sieve nano-seed crystal; preparing a synthetic mother liquor from the silicon source, the aluminum source, the alkali and water; and coating a carrier with the A type molecular sieve nano-seed crystal, placing the carrier in the synthetic mother liquor, and carrying out hydrothermal crystallization at 20-45 DEG C for 2-10 d to obtain the ultrathin A type molecular sieve membrane. The size of the molecular sieve crystal synthesized in the present invention is reduced from 1 [mu]m to about 300-500 nm, so the thickness of the membrane is reduced to about 1 [mu]m, and the permeation flux is high. In addition, the reduction of the crystallization temperature can slow down the formation process of the molecular sieve membrane and facilitate the cross-linking between the molecular sieve crystals, so generated defects are reduced, and the separation selectivity is high. The synthesis of the A type molecular sieve membrane at room temperaturemakes the synthesis process consume no energy, so energy saving and environmental protection are benefited. The synthesized A type molecular sieve membrane has a high flux and a high separation coefficient in solvent dehydration.

Description

technical field [0001] The invention relates to the technical field of membrane separation, in particular to a method for synthesizing type A molecular sieve membrane at low temperature. Background technique [0002] A large number of research reports have shown that membrane separation has the advantages of low energy consumption, continuous operation, low equipment investment, small volume, and easy maintenance, and has great application potential in the fields of gas separation, solvent dehydration, air separation, and olefin-alkane separation. [Ind. Eng. Chem. Res. 41 (2002) 1393]. Molecular sieve membranes have uniform molecular-scale pores and unique adsorption properties, coupled with excellent thermal, chemical and mechanical stability, and have broad application prospects in the field of separation. Type A molecular sieve is a small-pore molecular sieve with strong hydrophilicity and is widely used in the fields of drying, solvent dehydration and ion exchange. Typ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/14
CPCC01B39/14C01P2004/03C01P2002/72
Inventor 王明全张野张延风
Owner SHANGHAI UNIV OF ENG SCI
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