Preparation method of layer-by-layer self-assembled hollow fiber forward osmosis membrane

A layer-by-layer self-assembly, forward osmosis membrane technology, applied in semi-permeable membrane separation, chemical instruments and methods, membrane technology, etc. problem, to achieve the effect of stable moisturizing effect, easy control of operating cost and low reverse salt flux

Active Publication Date: 2018-07-27
西安金藏膜环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the problems of the existing forward osmosis hollow fiber membranes, such as complex membrane manufacturing process, uncontrollable thickness of the functional layer, low charge density of the polarized layer leading to serious internal concentration polarization, etc., adopts self-assembled polarized layer and interface The preparation process of the polymeric functional selective layer provides a preparation method of a layer-by-layer self-assembled hollow fiber forward osmosis membrane with high charge capacity and strong selectivity

Method used

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preparation example Construction

[0030] The invention discloses a method for preparing a hollow fiber forward osmosis membrane, comprising:

[0031] 1) Preparation of layer-by-layer self-assembled hollow fiber forward osmosis base membrane: first, inorganic additives (lithium chloride, zinc chloride, graphene oxide, carbon nitride doped graphene, carbon nano tube, silicon dioxide or titanium dioxide, or a mixture of several) uniformly dissolved in 75-85% organic solvents (N-N dimethylformamide DMF, N-N dimethylacetamide DMAc, dimethylformamide sulfoxide DMSO, nitrogen methylpyrrolidone NMP, lactic acid, 1,4-dioxane or acetone or a mixture of the above solvents) to obtain an organic solution, and then 13 to 20% of the polymer ( Polyacrylonitrile PAN, polysulfone PSF, polyethersulfone PES, polyvinylidene fluoride PVDF, polybenzimidazole PBI, cellulose acetate CA or triacetate cellulose CTA) added to the above organic In the solution, keep stirring at 20-95°C for 10-24 hours, and vacuum defoaming at 20-60°C for...

Embodiment 1

[0040] 1) Preparation of hollow fiber forward osmosis base membrane: Lithium chloride with a mass ratio of 4% is uniformly dissolved in 80% N~N dimethylacetamide DMAc, and then 16% polyacrylonitrile PAN is added to the above-mentioned In the organic solution, stir at 60°C for 24h, and then vacuum defoam at 25°C for 24h to obtain a homogeneous casting solution. The homogeneous casting liquid is transported to the spinneret through a metering pump under the pressure of 0.05Mpa nitrogen, and the internal pressure of the casting liquid is controlled to make the thickness of the casting liquid controllable and evenly distributed. At the same time, deionized water is introduced into the spinneret In the internal channel of the head, the extruded casting solution is phase-inverted into a membrane in the external coagulation bath to obtain a self-supporting hollow fiber membrane;

[0041] 2) Surface activation modification of hollow fiber ultrafiltration base membrane: immerse the obt...

Embodiment 2

[0047] 1) Preparation of hollow fiber forward osmosis base membrane: Graphene oxide with a mass ratio of 5% is uniformly dissolved in 75% N~N dimethylformamide DMF, and then 20% polysulfone PSF is added to the above organic The solution was stirred at 20°C for 18h, and then vacuum defoamed at 20°C for 48h to obtain a homogeneous casting solution. The homogeneous casting solution is delivered to the spinneret through a metering pump under 0.1Mpa nitrogen pressure, and the internal pressure of the casting solution is controlled to make the thickness of the casting solution controllable and evenly distributed, and at the same time, deionized water is introduced into the spinneret In the internal channel of the head, the extruded casting solution is phase-inverted into a membrane in the external coagulation bath to obtain a self-supporting hollow fiber membrane;

[0048] 2) Surface activation modification of hollow fiber ultrafiltration base membrane: immerse the obtained self-sup...

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Abstract

The invention discloses a preparation method of a layer-by-layer self-assembled hollow fiber forward osmosis membrane. The preparation method comprises the steps of: preparing hollow fiber forward osmosis base film, modifying hollow fiber ultrafiltration base film, repeating layer-by-layer assembly of polycation and polyanion layers, performing interface cross-linking polymerization for preparinga selective functional layer, conducting moisturizing, and carrying out treatment and storage so as to prepare the layer-by-layer self-assembled hollow fiber forward osmosis membrane. The surface of the hollow fiber self-support base film which is prepared by using a phase conversion method is activated firstly, layer-by-layer assembly of polycation and polyanion is repeated on the surface of thefilm so as to form an functional polarization layer for an electrolyte solution, and the polyamide selective layer is prepared through interfacial chemical cross-linking polymerization. The prepared hollow fiber forward osmosis membrane has a controllable thickness and an internal polarization layer with a high charge capacity, and the internal concentration polarization phenomenon can be alleviated effectively during the forward osmosis process; therefore, the hollow fiber forward osmosis membrane can simultaneously obtain high flux and low reverse salt flux, has high filtration separation efficiency, easy cleaning and a long service life, and can be widely applied to seawater desalination and concentration and desalination of brine.

Description

technical field [0001] The invention belongs to the field of separation membrane preparation, and in particular relates to a preparation method of a layer-by-layer self-assembled hollow fiber forward osmosis membrane. Background technique [0002] In recent years, forward osmosis, as a new green membrane separation technology, has gradually attracted widespread attention from scholars at home and abroad. Compared with reverse osmosis, nanofiltration, ultrafiltration and other pressure-driven membrane technologies, forward osmosis does not need or only requires a very low pressure to realize pure water from the side with lower osmotic pressure through the selective semi-permeable membrane to enter the high permeability On the pressure side, the whole process is driven by the osmotic pressure difference. Therefore, forward osmosis membrane separation technology has the advantages of low energy consumption, low pollution, high water recovery rate, etc., and has a wide range of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/76B01D71/68B01D71/42B01D71/34B01D71/16B01D69/08B01D67/00B01D61/00
CPCB01D61/002B01D67/0006B01D69/08B01D71/16B01D71/34B01D71/42B01D71/68B01D71/76Y02A20/131
Inventor 王磊张慧慧黄丹曦陈立成王旭东
Owner 西安金藏膜环保科技有限公司
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