A preparation method of hydrophobic nano-mesoporous molecular sieve filled PDMS composite membrane

A mesoporous molecular sieve, hydrophobic nanotechnology, applied in chemical instruments and methods, membrane technology, semi-permeable membrane separation, etc., can solve problems such as poor swelling resistance and increase physical cross-linking degree.

Active Publication Date: 2011-12-28
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, PDMS has poor swelling resistance in the MeOH/DMC azeotropic mixture. Generally, it is filled with inorganic particles to suppress the swelling of the membrane, e...

Method used

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  • A preparation method of hydrophobic nano-mesoporous molecular sieve filled PDMS composite membrane
  • A preparation method of hydrophobic nano-mesoporous molecular sieve filled PDMS composite membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Dissolve nano-mesoporous molecular sieve MCM-41 in toluene, prepare a solution with a mass concentration of 5%, stir and disperse, add octadecyltrichlorosilane with 50% mass of nano-mesoporous molecular sieve MCM-41, and stir at 50°C for 12h , filtered, washed with toluene, and dried at 300°C to obtain hydrophobic nano-mesoporous molecular sieve MCM-41; 10g RTV615-A, 1.5g RTV615-B were dissolved in 11.2g toluene, and then 5g of the above-mentioned hydrophobic nano-mesoporous molecular sieve was added Pore ​​molecular sieve MCM-41, stir well; scrape the film on the polysulfone (PS) porous bottom film, and dry it in an oven at 80°C for 10 hours to make it completely cross-linked to obtain a composite film. When the concentration of dimethyl carbonate in the feed liquid is 30wt%, the operating temperature is 40°C, and the absolute pressure behind the membrane is 400Pa, the separation factor of the above membrane is 3.88, and the permeation flux is 0.958kg / m 2 h.

Embodiment 2

[0032] Dissolve nanometer mesoporous molecular sieve MCM-48 in n-hexane, prepare a solution with a mass concentration of 15%, stir and disperse, add dropwise octyltrichlorosilane with 10% mass of mesoporous molecular sieve MCM-48, stir at 100°C for 6h, filter After washing with n-hexane and drying at 100°C, hydrophobic nano-mesoporous molecular sieve MCM-48 was obtained; 5g of 107 type PDMS with a viscosity of 50000mpa s, 0.5g of crosslinking agent ethyl orthosilicate, 0.17g of catalyst II Dibutyltin laurate, dissolved in 24.9g of n-hexane, then add 5g of the above-mentioned hydrophobic nano-mesoporous molecular sieve MCM-48, stir evenly; scrape the film on the polyvinylidene fluoride (PVDF) porous bottom film, and keep it in an oven at 100°C Dry it for 8 hours to make it completely cross-linked to obtain a composite membrane. When the concentration of dimethyl carbonate in the feed liquid is 30wt%, the operating temperature is 40°C, and the absolute pressure behind the membra...

Embodiment 3

[0034]Dissolve nano-mesoporous molecular sieve MCM-41 in cyclohexane, prepare a solution with a mass concentration of 30%, stir and disperse, add dodecamethyltrichlorosilane with a mass of nano-mesoporous molecular sieve MCM-41 of 30%, at 70°C Stir for 36 hours, filter, wash with cyclohexane, and dry at 200°C to obtain hydrophobic nano-mesoporous molecular sieve MCM-41; mix 10g of 108-type PDMS with a viscosity of 10000mpa s, 1g of cross-linking agent phenyltrimethoxysilane , 0.33g of catalyst dibutyltin dilaurate, dissolved in 17.75g of n-heptane, then add 0.5g of the above-mentioned hydrophobic nano-mesoporous molecular sieve MCM-41, stir evenly; , and kept in an oven at 120°C for 4 hours to make it completely cross-linked to obtain a composite film. When the concentration of dimethyl carbonate in the feed liquid is 30wt%, the operating temperature is 40°C, and the absolute pressure behind the membrane is 400Pa, the separation factor of the above membrane is 3.38, and the pe...

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Abstract

The invention discloses a preparation method of a hydrophobic nano mesoporous molecular sieve filling PDMC composite film, comprising the following steps: using a casting solution containing polydimethylsiloxane (PDMS), hydrophobic mesoporous molecular sieve, cross-linking agent, catalyst, and solvent to wipe film on the upper layer of a porous ultrafiltration membrane supported by polyester non-woven, and heating until crosslinking completely to obtain the composite film. The obtained mesoporous molecular sieve modified by surface silane coupling agent is combined with the PDMS substrate tightly, and is dispersed uniformly in the PDMS substrate. The preparation method has the advantages of simple process and cheap selected materials. The composite film has strong swelling resistance in dimethyl carbonate(DMC)/methanol azeotrope, and excellent DMC permselective property. When the filling weight ratio of the mesoporous molecular sieve is 30 %, the separation factor alfa is 4.07, the penetration flux J is 1.13 kg/m<2>h([DMC]=30 wt%, 40 DEG C).

Description

technical field [0001] The invention relates to the technical field of pervaporation membrane separation, in particular to a method for preparing a hydrophobic nanometer mesoporous molecular sieve filled PDMS composite membrane which can be used for pervaporation separation of dimethyl carbonate / methanol azeotropic liquid. Background technique [0002] Dimethyl carbonate (DMC) is an environmentally friendly chemical. It can replace phosgene, dimethyl sulfate, etc. as a methylating agent and carbonylating agent to synthesize a variety of green high-tech fine chemicals. At the same time, as a green and low-toxic solvent, it is widely used in coatings, medicine, pesticides and other industries. The industrial production of DMC obtains methanol (MeOH) / DMC azeotropic mixture, and under normal pressure, the mass fraction of DMC in the azeotrope is 30%. The high energy consumption required for separation by the pressure distillation method greatly increases the production cost of...

Claims

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Application Information

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IPC IPC(8): B01D71/70B01D69/12B01D67/00
Inventor 李继定王蕾郑冬菊秦琳陈剑
Owner TSINGHUA UNIV
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