NaA molecular sieve membrane element internal membrane preparation method

[0032] Example 1

[0033] The preparation device of NaA molecular sieve inner membrane provided by the present invention is as follows figure 1 As shown, the preparation steps are as figure 2 Shown.

[0034] Step 1: Preparation of seeded support

[0035] Such as figure 1 As shown, 10g of NaA molecular sieve seeds with an average particle size of about 2μm were weighed, dispersed in 990g of deionized water, and placed in the seed tank 2 on the stirrer 1, after stirring for 10 hours, ultrasonic dispersion for 30 minutes, to obtain NaA type Molecular sieve seed suspension 3, the concentration of the seed suspension is 10g/L; fix the mullite single tube support body 5 with Teflon raw material tape wound on the outer surface of the sealed two ends in the membrane module 4. The end sealing method of the pipe support body is as follows image 3 As shown in the middle shaded part, the end surface of one end of the single tube and the outer wall of the end part are coated with glue or glaze to solidify to prevent part of the organic solvent from penetrating through the end of the support body and the outer wall of both ends during the pervaporation dehydration process. The vacuum side affects the separation performance of the membrane. Subsequently, the NaA molecular sieve seed suspension 3 was transported to the inner cavity of the support body 5 through the conveying device 6 constant flow pump at a flow rate of 0.7 m/s, and the molecular sieve suspension 3 was circulated back to the seed tank 2, and the ball valve 7 was used to control the circulation after 5 seconds At the end, change the circulating flow direction of the molecular sieve suspension to circulate in the support body again for 5 seconds, and then circulate and empty the inner cavity of the support body 5 and the seed solution in the pipeline in the reverse direction (with the flow direction of the suspension of the last crystal coating On the contrary), the support body 5 is then taken out and put in an oven to dry for later use.

[0036] Step 2: Preparation of NaA molecular sieve membrane

[0037] Sodium metaaluminate is added to sodium hydroxide and deionized water and fully stirred to form an aluminum solution. After clarification, sodium silicate is added, and after vigorous stirring, a film-forming solution for preparing NaA molecular sieve membrane is formed. The molar ratio of the raw materials of the membrane-making liquid is A1 2 O 3 :SiO 2 :Na 2 O:H 2 O=1:2:2:120 conversion. Fix the seeded support vertically in the reaction kettle, add the film-making solution, seal it and place it in a rotating oven at 100℃ for hydrothermal synthesis, crystallize 3h/time, take it out after twice, remove the outer wall of the support After cooling the coated PTFE tape, the membrane tube is cleaned with deionized water until the pH of the cleaning solution is 7, and then dried at 100°C for characterization and pervaporation experiments.

[0038] Example 2

[0039] Step 1: Preparation of seeded support

[0040] Weigh 10g of NaA molecular sieve seeds with an average particle size of about 2μm, disperse them in 990g of deionized water, stir for 10 hours and then ultrasonically disperse for 30 minutes to obtain a NaA molecular sieve seed suspension with a concentration of 10g/L; A mullite five-channel support (50μm thick) wrapped with polytetrafluoroethylene raw material tape on the sealed outer surfaces of both ends is fixed in the membrane module, and then the NaA molecular sieve suspension is transported to the membrane at a flow rate of 0.5m/s through a diaphragm pump In the inner cavity of the support body 5, the molecular sieve suspension is circulated back to the seed tank. After the circulation time is controlled to 10s, the seed suspension in the inner cavity and the pipeline of the support body is emptied in the opposite direction (with the flow direction of the suspension when the crystal is coated On the contrary), the support is then taken out and placed in an oven to dry for later use.

[0041] Step 2: Preparation of NaA molecular sieve membrane

[0042] The aluminum foil is added with sodium hydroxide and deionized water and fully stirred to form an aluminum solution. After clarification, sodium metasilicate is added, and after vigorous stirring, a film-making solution for preparing NaA molecular sieve membrane is formed. The molar ratio of the raw materials of the membrane-making liquid is A1 2 0 3 :SiO 2 :Na 2 O:H 2 O=1:1:10:100 conversion. The seeded support was vertically fixed in the reaction kettle, and the film-making solution was added, sealed, and then placed in a rotating oven at 150° C. to rotate for hydrothermal synthesis. After crystallization for 0.5 h, it was taken out. The PTFE raw material tape coated on the outer wall of the support is removed. After cooling, the membrane tube is cleaned with deionized water until the pH of the cleaning solution is 6, and then dried at 100°C for characterization and pervaporation experiments.

[0043] Example 3

[0044] Step 1: Preparation of seeded support

[0045] Weigh 100g of NaA molecular sieve seeds with an average particle size of about 10μm, disperse them in 900g of deionized water, stir for 10h, and ultrasonically disperse for 30min to obtain a NaA molecular sieve seed suspension with a concentration of 100g/L; The aluminum oxide four-channel support body wrapped with PTFE raw material tape on the sealed outer surface at both ends is fixed in the membrane module, and then the NaA molecular sieve suspension is transported to the inner cavity of the support body at a flow rate of 0.01 m/s through a slurry pump. The molecular sieve suspension is circulated in the seed tank. After 30 seconds of circulation, the inner cavity of the support and the seed suspension in the pipeline are emptied in the opposite direction, and then the support is taken out and placed in an oven for drying for use.

[0046] Step 2: Preparation of NaA molecular sieve membrane

[0047] Add sodium aluminate to sodium hydroxide and deionized water and stir fully to form an aluminum solution. Add sodium silicate to sodium hydroxide and deionized water and stir fully to form a silicon solution. After both are clear, add the silicon solution The aluminum solution is vigorously stirred to form a film forming solution for preparing NaA molecular sieve membranes. The molar ratio of the raw materials of the membrane-making liquid is A1 2 O 3 :SiO 2 :Na 2 O:H 2 O=1:5:50:980 conversion. The seeded support was vertically fixed in the reaction kettle, and the film-making liquid was added to the reactor to seal it, and then placed in a 70°C rotating oven to rotate and crystallize twice for 4 hours before taking it out. The PTFE raw material tape coated on the outer wall of the support is removed. After cooling, the membrane tube is cleaned with deionized water until the pH of the cleaning solution is 8, and then dried at 120°C for characterization and pervaporation experiments.