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CN-121988176-A - Regeneration method of molecular sieve membrane, regenerated molecular sieve membrane and application

CN121988176ACN 121988176 ACN121988176 ACN 121988176ACN-121988176-A

Abstract

The invention provides a regeneration method of a molecular sieve membrane, the regenerated molecular sieve membrane and application. The invention provides a regeneration method of a molecular sieve membrane, which comprises the steps of adopting alkali liquor to treat the used molecular sieve membrane to obtain an alkali treated molecular sieve membrane, mixing the alkali treated molecular sieve membrane with membrane preparation liquor, and crystallizing to obtain the regenerated molecular sieve membrane. The molecular sieve membrane synthesized by the invention has high yield, uniform and compact regenerated molecular sieve membrane, high repeatability, low synthesis cost, convenient large-scale preparation and better industrial utilization prospect.

Inventors

  • CHEN CHONG
  • LV JIANGANG
  • SUN HUAQIAN
  • CHEN LONG
  • SHAO YI

Assignees

  • 中国石油化工股份有限公司
  • 中石化（上海）石油化工研究院有限公司

Dates

Publication Date
20260508
Application Date
20241107

Claims (10)

  1. 1. A method of regenerating a molecular sieve membrane comprising the steps of: s1, treating the used molecular sieve membrane by adopting alkali liquor to obtain an alkali treated molecular sieve membrane; S2, mixing the alkali-treated molecular sieve membrane with membrane preparation liquid, crystallizing to obtain a regenerated molecular sieve membrane, Preferably, the concentration of the lye is 0.5mol/L to 2.5mol/L and the temperature of the treatment is 30 ℃ to 90 ℃.
  2. 2. The method according to claim 1, wherein the alkaline solution is selected from one or more of sodium hydroxide solution, potassium hydroxide solution and sodium carbonate solution, and/or The concentration of the lye is 0.5mol/L to 2mol/L, preferably 0.7mol/L to 1.5mol/L, and/or The volume ratio of the support of the used molecular sieve membrane to the alkali liquor is 1:10-1:100, preferably 1:10-1:50.
  3. 3. The regeneration process according to claim 1 or 2, wherein in step S1 the temperature of the treatment is between 30 ℃ and 80 ℃, preferably between 50 ℃ and 70 ℃, and/or The treatment time is 0.5h-10h, preferably 1h-5h.
  4. 4. The method according to any one of claims 1 to 3, wherein in step S1, amorphous silica alumina and optional crystal grains are attached to the surface of the support of the alkali-treated molecular sieve membrane, Preferably, the grains have a coverage of 5% to 10% of the support surface, the amorphous aluminosilicate has a coverage of at least 60%, preferably at least 80%, more preferably at least 90%, for example 90% to 95%, Preferably, the grain size of the crystal grains is 200-300nm; preferably, the pore size of the support of the alkali-treated molecular sieve membrane is 700-1000nm.
  5. 5. The regeneration method according to any one of claims 1 to 4, wherein the used molecular sieve membrane is selected from one or more of the molecular sieve membranes used in alcohol dehydration, organic matter separation or water purification; preferably, the molecular sieve membrane after use has pores larger than 1 μm and no longer has separation performance; Preferably, the used molecular sieve membrane is selected from the group consisting of used LTA-type molecular sieve membranes, preferably from the group consisting of used NaA molecular sieve membranes.
  6. 6. The regeneration method according to any one of claims 1 to 5, characterized in that the support of the used molecular sieve membrane is selected from an alumina carrier tube and/or a hollow fiber tube; Preferably, the pore diameter of the support is 700-1000nm, and the wall thickness of the support is 2-4cm.
  7. 7. The method according to any one of claims 1 to 6, wherein in step S2, the film forming liquid includes an aluminum source, an alkali source, a silicon source, and water; Preferably, the aluminum source is calculated as Al 2 O 3 , the silicon source is calculated as SiO 2 , the alkali source is calculated as M 2 O, and M is selected from one or more of alkali metals, such as sodium or potassium, and the molar ratio of the aluminum source, the silicon source, the alkali source and water is 1 (0.5-3): 1-80): 100-800, preferably 1 (0.85-2): 3-50): 200-600; Preferably, the aluminium source is selected from aluminium sol and/or sodium metaaluminate, the silicon source is selected from one or more of silica sol, silica powder and sodium silicate, the alkali source is selected from sodium hydroxide, and/or In step S2, the crystallization temperature is 80-120 ℃, preferably 90-100 ℃, and/or the crystallization time is 1-10 h, preferably 3-6 h.
  8. 8. The method according to any one of claims 1 to 7, wherein in step S2, the crystallization comprises adding water to a crystallization kettle, coating a film-forming liquid on a support of the alkali-treated molecular sieve film, and placing the alkali-treated molecular sieve film on a support device for gas-phase crystallization, wherein the alkali-treated molecular sieve film is not in contact with water.
  9. 9. A regenerated molecular sieve membrane obtained by the regeneration method according to any one of claim 1 to 8, Preferably, the regenerated molecular sieve membrane has a thickness of 1-300 μm, preferably 10-200 μm; Preferably, the pore size of the regenerated molecular sieve membrane is 0.4-0.51nm.
  10. 10. Use of a regenerated molecular sieve membrane obtained according to the regeneration process of any one of claims 1 to 8 or of a regenerated molecular sieve membrane according to claim 9 in ethanol dehydration, organic matter separation and water purification.

Description

Regeneration method of molecular sieve membrane, regenerated molecular sieve membrane and application Technical Field The invention relates to the technical field of molecular sieve membranes, in particular to a regeneration method of a molecular sieve membrane, a regenerated molecular sieve membrane and application. Background Compared with the traditional industrial mainly adopted rectification separation, the membrane separation is an emerging, efficient and environment-friendly purification technology, and has the characteristics of low energy consumption, easiness in operation and preferential selectivity. The molecular sieve membrane is an inorganic membrane material with regular pore canal, controllable pore diameter and excellent chemical stability and mechanical strength, and can realize separation according to the size, shape or polarity of the separated molecules. LTA type molecular sieve can be continuously crystallized on a porous tubular alumina support to form a densely-stacked membrane layer, and is commonly used for dehydrating organic matters due to high hydrophilicity and proper pore size (about 0.42 nm), so that the LTA type molecular sieve is the most commonly used preferential water permeable membrane at present. Currently, exposure to the outside of the tube is susceptible to damage to the integrity of the membrane due to the structural particularities of the molecular sieve membrane. From the industrial application point of view, if a simple regeneration method can be developed, the method has great significance on the economic benefit in the field of organic matter dehydration. Disclosure of Invention The invention aims to overcome the defects in the prior art and provides a regeneration method of a defective molecular sieve membrane. The molecular sieve membrane synthesized by the invention has high yield, uniform and compact regenerated molecular sieve membrane, high repeatability, low synthesis cost, convenient large-scale preparation, good separation effect in ethanol dehydration test and industrial utilization prospect. In a first aspect, the present invention provides a method of regenerating a molecular sieve membrane comprising the steps of: s1, treating the used molecular sieve membrane by adopting alkali liquor to obtain an alkali treated molecular sieve membrane; S2, mixing the alkali-treated molecular sieve membrane with membrane preparation liquid, and crystallizing to obtain the regenerated molecular sieve membrane. The molecular sieve membrane (defect molecular sieve membrane) after the proper alkali liquor treatment is used, so that the molecular sieve membrane layer is not adhered to the surface of the support body, and the dissolved molecular sieve membrane layer can form uniform grain fragments and silicon-aluminum amorphous substances on the surface of the support body, so that on one hand, the grain fragments and the silicon-aluminum amorphous substances cover macropores of the support body, on the other hand, the grain fragments are used as seed crystals, the silicon-aluminum amorphous substances are used as crystallization raw materials, and the compact molecular sieve membrane can be obtained after one-time crystallization. In some embodiments, the lye is selected from one or more of sodium hydroxide solution, potassium hydroxide, sodium carbonate. In some embodiments, the lye concentration is 0.5mol/L to 2.5mol/L, for example 0.6mol/L、0.7mol/L、0.8mol/L、0.9mol/L、1.0mol/L、1.1mol/L、1.2mol/L、1.3mol/L、1.4mol/L、1.5mol/L、1.6mol/L、1.7mol/L、1.8mol/L、1.9mol/L、2.0mol/L、2.1mol/L、2.2mol/L、2.3mol/L、2.4mol/L or any value in between. In some embodiments, the lye concentration is 0.5mol/L to 2mol/L. In some embodiments, the lye concentration is 0.7mol/L to 1.5mol/L. In some embodiments, the volume ratio of support to the lye of the molecular sieve membrane after use is 1:10-1:100, e.g., 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:55, 1:60, 1:65, 1:70, 1:75, 1:80, 1:85, 1:90, 1:95, or any value therebetween. In some embodiments, the volume ratio of the support of the used molecular sieve membrane to the lye is 1:10 to 1:50. In some embodiments, in step S1, the temperature of the treatment is 30 ℃ to 90 ℃, e.g., 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, or any value therebetween. In some embodiments, in step S1, the temperature of the treatment is between 30 ℃ and 80 ℃. In some embodiments, the temperature of the treatment is 50 ℃ to 70 ℃. In some embodiments, in step S1, the treatment is for a time of 0.5h to 10h, for example 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or any value therebetween. In some embodiments, the treatment is for a period of time ranging from 1h to 5h. In some embodiments, in step S1, amorphous silica alumina material and optional crystallites are attached to the support surface of the alkali treated molecular sieve membrane. In some embodiments, the coverage of the grains on the support surface is 5% -10%, for example 6%, 7%, 8% o