Preparation method for composite forward osmosis membrane based on interfacial polymerization

An interfacial polymerization, forward osmosis membrane technology, used in semi-permeable membrane separation, chemical instruments and methods, membrane technology, etc., can solve the problems of unstable chemical properties, easy pollution, low porosity, etc., and achieve excellent chemical stability, Strong anti-pollution ability and the effect of enhancing adhesion

Active Publication Date: 2017-10-27
NINGBO UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] At present, the preparation of composite forward osmosis membranes by interfacial polymerization has the following disadvantages: most of the forward osmosis membrane materials are chemically unstable, and the composite forward osmosis membranes produced have poor mechanical strength, low flux, and are easy to pollute; Interfacial polymerization of membrane materials with poor water properties will form a composite layer that will not be firmly bonded to the base membrane and have poor stability. The addition of surfactants in the solution will pollute the interior of the obtained composite membrane; even if the membrane material with good hydrophilicity is used for interfacial polymerization, due to the low porosity and the surface of the base membrane is not rough enough, the composite layer generated by the interfacial polymerization reaction will be affected. The adhesive force is small, and the composite layer formed by the interfacial polymerization of the two active monomers is incomplete and easy to fall off

Method used

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  • Preparation method for composite forward osmosis membrane based on interfacial polymerization
  • Preparation method for composite forward osmosis membrane based on interfacial polymerization
  • Preparation method for composite forward osmosis membrane based on interfacial polymerization

Examples

Experimental program
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Effect test

Embodiment 1

[0035] Step 1: Accurately weigh 2g polyvinyl alcohol, 18g polyvinylidene fluoride, 80g caprolactam, polyvinylidene fluoride vinyl / polyvinyl alcohol is 9:1, polymer material mass fraction is 20%, polyvinyl alcohol, polyvinylidene Mix vinyl fluoride and caprolactam evenly and pour them into a 250ml beaker. The temperature of the oil bath used is 115°C. The heating process requires nitrogen protection. Heat for 0.5 hours to dissolve polyvinyl alcohol, polyvinylidene fluoride and caprolactam, and then stir the solution with an electric stirrer for 1.5 hour, then leave it to stand to obtain the casting solution.

[0036] Step 2: Pour the casting solution evenly into the mold that has been preheated to 115°C (such as figure 1 (shown), the mold was cooled at room temperature, and after the casting solution solidified and separated into phases, the mold was disassembled and placed in water at 4°C for extraction for 10 minutes to obtain a polyvinylidene fluoride-based film.

[0037] S...

Embodiment 2

[0042] Step 1: Accurately weigh 4g polyvinyl alcohol, 16g polyvinylidene fluoride, 80g caprolactam, polyvinylidene fluoride vinyl / polyvinyl alcohol is 8: 2, polymer material mass fraction is 20%, polyvinyl alcohol, polyvinylidene Mix vinyl fluoride and caprolactam evenly and pour them into a 250ml beaker. The temperature of the oil bath used is 145°C. The heating process requires nitrogen protection. Heat for 1.5 hours to dissolve polyvinyl alcohol, polyvinylidene fluoride and caprolactam, and then stir the solution with an electric stirrer 2 hour, then leave it to stand to obtain the casting solution.

[0043] Step 2: Pour the casting solution evenly into the mold that has been preheated to 145°C (such as figure 1 (shown), place the mold at room temperature to cool down, and after the casting solution solidifies and separates into phases, the mold is disassembled and placed in water at 25°C for extraction for 20 minutes to obtain a polyvinylidene fluoride-based film (its morp...

Embodiment 3

[0049] Step 1: Accurately weigh 5g polyvinyl alcohol, 20g polyvinylidene fluoride, 75g caprolactam, polyvinylidene fluoride ethylene / polyvinyl alcohol is 8:2, polymer material mass fraction is 25%, polyvinyl alcohol, polyvinylidene Mix vinyl fluoride and caprolactam evenly and pour them into a 250ml beaker. The temperature of the oil bath used is 170°C. The heating process requires nitrogen protection. Heat for 2 hours to dissolve polyvinyl alcohol, polyvinylidene fluoride and caprolactam, and then stir the solution with an electric stirrer for 3.5 hour, then leave it to stand to obtain the casting solution.

[0050] Step 2: Pour the casting solution evenly into the mold that has been preheated to 170°C (such as figure 1 (shown), the mold was cooled at room temperature, and after the casting solution was solidified and separated into phases, the mold was disassembled and placed in water at 25°C for extraction for 30 minutes to obtain a polyvinylidene fluoride-based film.

[0...

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Abstract

The invention relates to a preparation method for a composite forward osmosis membrane based on interfacial polymerization. Polyvinyl alcohol is used as a hydrophilic modification material of polyvinylidene fluoride, caprolactam is used as a diluent, and a thermally induced phase separation method is applied to prepare a hydrophilic modified polyvinylidene fluoride base membrane under a relatively low temperature condition, the base membrane is symmetrical in structure and high in porosity, and the upper and lower surfaces are rough and have micropore structures; and m-phenylenediamine is used as a water-phase monomer, trimesoyl chloride is used as an oil-phase monomer, and interfacial polymerization is performed on the surface of the polyvinylidene fluoride base membrane to prepare the composite forward osmosis membrane with excellent chemical stability. The composite forward osmosis membrane is high in water flux and low in reverse osmosis percentage of salts, and the composite forward osmosis membrane has the advantages of higher strength, acid resistance and alkali resistance, high hydrophilcity, high anti-pollution ability, compact composite layers, firm combination and uneasiness to fall off.

Description

technical field [0001] The patent of the invention belongs to the field of membrane manufacturing, specifically, it relates to a composite forward osmosis membrane prepared by thermally induced phase separation and then prepared by interfacial polymerization. The composite forward osmosis membrane can be used In environmental protection, water treatment and other fields. Background technique [0002] Forward osmosis technology utilizes the osmotic pressure difference on both sides of the semi-permeable membrane under normal pressure to realize the spontaneous separation of the solution, which shows great potential in solving the contradiction between water source and energy. However, due to the shortage of high-performance membranes, the development of this technology has been inhibited for a long time. The permeable membranes that perform well in the pressure-driven process have serious internal concentration polarization effects in the process, resulting in a much lower pe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/34B01D71/38B01D69/12B01D69/02B01D67/00
CPCB01D67/0002B01D69/02B01D69/125B01D71/34B01D71/38
Inventor 胡宁恩肖通虎谢家礼
Owner NINGBO UNIV
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