CN101961606B - Process for preparing ethylenediaminetetraacetic dianhydride modified polyvinylidene fluoride separation membrane and resin - Google Patents

Abstract

The invention provides a kind of reagents such as ethylenediaminetetraacetic dianhydride, sodium hydroxide, sodium borohydride, tetrabutylammonium bromide, p-toluenesulfonic acid, N, N-dimethylacetamide, polyvinylpyrrolidone as Raw materials, the process of preparing ethylenediamine tetraacetic acid dianhydride modified polyvinylidene fluoride separation membrane and resin by chemical blending/phase transfer technology, this process has the advantages of simple operation and uniform blending. This technology uniformly blends ethylenediamine tetraacetic acid polyaminopolycarboxylic acid compound in polyvinylidene fluoride separation membrane and resin, which effectively improves the hydrophilic performance of polyvinylidene fluoride microfiltration separation membrane and resin, and realizes polyvinylidene fluoride separation membrane and resin. The removal of complexed heavy metal ions in wastewater by vinyl fluoride separation membranes and resins improves the efficiency of polyvinylidene fluoride separation membranes and resins for drinking water purification, promotes the removal and resource utilization of heavy metal pollutants, and expands the scope of polyvinylidene fluoride separation membranes and resins. Application of vinyl fluoride separation membrane and resin in the field of water treatment.

Description

Preparation process of polyvinylidene fluoride separation membrane and resin modified by ethylenediaminetetraacetic acid dianhydride

technical field

The present invention relates to the performance improvement of polyvinylidene fluoride macromolecular materials, in particular to a method using ethylenediaminetetraacetic dianhydride, sodium hydroxide, sodium borohydride, tetrabutylammonium bromide, p-toluenesulfonic acid, N, N-dimethylacetamide and other reagents are used as raw materials, and chemical blending/phase transfer technology is used to modify the preparation process of polyvinylidene fluoride separation membranes and resins.

Background technique

Polyvinylidene fluoride separation membrane technology has the advantages of normal temperature operation, no phase change, obvious energy saving effect, high filtration accuracy, low production pollution, large water output and good quality. Through the screening and interception of the membrane, it has an excellent removal effect on suspended particles and colloidal pollutants in the water body. Polyvinylidene fluoride separation membranes have excellent pollution resistance and chemical oxidation resistance, and can effectively remove suspended particles and colloidal pollutants in water, but conventional polyvinylidene fluoride separation membranes cannot remove water-soluble heavy metal ions. In order to effectively remove polyvinylidene fluoride separation membranes and resins from free and organic complex heavy metal pollutants in water, it should be modified to introduce functional groups with chelating coordination into separation membranes and resins.

In the heavy metal pollution treatment process, the widely used chemical precipitation treatment technology has the disadvantages of high treatment cost and serious secondary pollution. Adsorption method, including ion exchange and adsorption, is a potential application prospect to solve heavy metal pollution in water. However, conventional adsorption materials such as activated carbon and fly ash have the disadvantages of low adsorption capacity and slow adsorption rate. Therefore, the development and application of new adsorption materials with uniform pore size distribution, large specific surface area, high adsorption capacity, fast adsorption rate, and stable physical and chemical properties are important measures to solve heavy metal pollution in water. Polyvinylidene fluoride separation membranes and resins have the advantages of anti-pollution, resistance to chemical oxidation, and stable action against microorganisms, as well as excellent mechanical properties and stable physical and chemical properties. However, conventional polyvinylidene fluoride separation membranes and resins cannot remove water-soluble heavy metal pollutants in water bodies.

The research and development of separation membranes and new adsorption materials with excellent performance has always been the focus of research in the field of polymer materials, and domestic and foreign are committed to the research and development of new separation membranes and adsorption materials. For the fields of heavy metal pollution control, sewage treatment and reuse, separation membranes and resins made of polyvinylidene fluoride have good pollution resistance and resistance to chemical oxidation, which has increasingly attracted people's attention. At present, the focus of research on polyvinylidene fluoride materials is the research on surface graft modification, especially the improvement of polyvinylidene fluoride separation membrane and resin hydrophilic properties. Improving the hydrophilic properties of polyvinylidene fluoride separation membranes and resins, and improving the processing performance of separation membranes and resins will be the difficulties and focus of various developers and research institutes. Many scholars have used polyvinyl alcohol, acrylic acid, acrylamide, polyacrylic acid and other reagents to carry out research on the hydrophilic modification of polyvinylidene fluoride separation membranes and resin surfaces by using techniques such as radiation induction, plasma induction, and ozone oxidation. Grafting carboxylic acid groups and hydroxyl groups with hydrophilic properties effectively improves the hydrophilic properties of polyvinylidene fluoride separation membranes and resins, and realizes the adsorption and removal of free heavy metal pollutants. However, surface grafting modification will have adverse effects on the physical properties of the separation membrane and resin, such as changing the microporous structure and pore size distribution on the surface of the separation membrane and resin, the grafted hydrophilic groups will fall off, and the grafted acrylic acid will polymerize. Polyvinylidene fluoride separation membranes and resins with compound and sulfonic acid functional groups have low removal efficiency for complexed heavy metal ions in water. In addition, polyvinylidene fluoride separation membranes and resins are modified by using ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid and melamine, which can realize the blending and bonding of polyaminopolycarboxylic acid functional groups with chelating coordination. branches into polyvinylidene fluoride separation membranes and resins, but the reaction often requires high temperatures above 160°C, and the control of reaction conditions is very strict. The existence of these problems will affect the performance of polyvinylidene fluoride separation membrane and resin, and ultimately limit the application of polyvinylidene fluoride separation membrane and resin in the field of water treatment.

Contents of the invention

In order to overcome the above-mentioned deficiencies in the prior art, the present invention provides a preparation process for ethylenediaminetetraacetic dianhydride modified polyvinylidene fluoride separation membrane and resin, through chemical blending/phase transfer technology, in polyvinylidene fluoride The separation membrane and resin are uniformly doped with ethylenediaminetetraacetic acid polyaminopolycarboxylic acid compound, so that polyvinylidene fluoride separation membrane and resin are evenly blended with polyaminopolycarboxylic acid functions with hydrophilic properties and chelating coordination properties The group improves the hydrophilic properties of the separation membrane and resin, realizes the removal of free and complex heavy metal ions in water, further improves the quality of drinking water, removes and recycles heavy metal ions in industrial wastewater, and effectively solves the problem of water environment. Heavy metal pollution has promoted the resource utilization of heavy metal pollutants.

The preparation process of ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride separation membrane and resin is:

1) Preparation of chemical solution used for alkalization of polyvinylidene fluoride:

Add 150-180g of sodium hydroxide and 3-7g of tetrabutylammonium bromide into 1L of deionized water in sequence, stir to dissolve them all, and the conductivity of the deionized water is 5-10μs/cm;

2) Alkaline treatment of polyvinylidene fluoride:

a. After all the components in the chemical alkalization solution are dissolved, the temperature is raised slowly. When the temperature rises to 80°C, add polyvinylidene fluoride particles with an average particle size of 0.05mm and a mass of 400g to the chemical alkali In the chemical solution, keep the solution temperature at 75-85°C, and the alkalization treatment time is 8 hours;

b. After alkalization for 8 hours, take out the polyvinylidene fluoride particles from the chemical alkalization solution, wash them with deionized water, and dry them at 60-80°C;

3) The composition of the blended casting solution used in the preparation of ethylenediaminetetraacetic acid dianhydride-modified polyvinylidene fluoride separation membrane by chemical blending/phase transfer technology is as follows:

a. Ethylenediaminetetraacetic acid dianhydride 150-200g/L, sodium borohydride 4-7g/L, alkalized polyvinylidene fluoride 120-150g/L, p-toluenesulfonic acid 1-3g/L, polyethylene Pyrrolidone 30～50g/L;

b. The solvent used is N,N-dimethylacetamide;

c. The order of adding each reagent is: first add sodium borohydride, then alkalized polyvinylidene fluoride, secondly p-toluenesulfonic acid, and finally ethylenediaminetetraacetic dianhydride and polyvinylpyrrolidone;

4) Preparation steps of ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride separation membrane by chemical blending/phase transfer technology:

a. Using chemical blending/phase transfer technology to prepare ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride separation membrane, in a three-necked flask, add sodium borohydride to N,N-dimethylacetamide solvent , so that the temperature of the solvent is slowly raised to 120°C; when the temperature of the solvent rises to 120°C, quickly add the alkalized polyvinylidene fluoride into the solvent, keep the temperature of the casting solution at 118-122°C, and react for 3 hours. Condensation and reflux should be used in the whole process from the heating of the solvent to the heat preservation reaction for 3 hours; In the solution, stir and react for 2 hours, from the addition of p-toluenesulfonic acid to the stirring reaction for 2 hours, the whole process needs to be protected by nitrogen gas; after nitrogen gas is passed for 2 hours, the nitrogen gas is stopped, and polyvinylpyrrolidone is added to the blended casting solution, stirred and dissolved, and finally Control the temperature at 70°C to 80°C and stir magnetically to dissolve and fully blend the components in the casting solution for 6 hours; after stirring for 6 hours, place the blended casting solution in a water bath for 6 to 9 hours of defoaming, and the temperature of the water bath is 50°C to 60°C;

b. ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride flat film is made on smooth glass with a medical scraper, and then formed into a film in a water condensation bath. The ethylene hollow fiber membrane is drawn by a spinning machine, the core fluid is 5% ethanol aqueous solution, the flow rate is 1.2-1.8mL/min; 35 meters, the condensation bath is deionized water, its conductivity is 20-30μs/cm, and the water temperature is 40°C-50°C;

c. Ethylenediaminetetraacetic acid dianhydride modified vinylidene fluoride hollow fiber membranes and flat membranes are first soaked in deionized water for 48 hours, then soaked in 0.1-0.5mol/L hydrochloric acid solution for 24 hours, taken out and washed, soaked in volume Preserve in 0.5-2% hydrogen peroxide aqueous solution;

5) The composition of the blended casting solution used in the preparation of ethylenediaminetetraacetic dianhydride modified polyvinylidene fluoride resin by chemical blending/phase transfer technology is as follows:

a. Ethylenediaminetetraacetic acid dianhydride 180-250g/L, sodium borohydride 4-7g/L, alkalized polyvinylidene fluoride 100-130g/L, p-toluenesulfonic acid 1-3g/L, polyethylene Pyrrolidone 30～50g/L;

b. The solvent used is N,N-dimethylacetamide;

c. The order of adding each reagent is: first add sodium borohydride, then alkalized polyvinylidene fluoride, secondly p-toluenesulfonic acid, and finally ethylenediaminetetraacetic dianhydride and polyvinylpyrrolidone;

6) Preparation steps of ethylenediaminetetraacetic dianhydride modified polyvinylidene fluoride resin by chemical blending/phase transfer technology:

a. Prepare ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride resin by chemical blending/phase transfer technology. In a three-necked flask, sodium borohydride is added to N,N-dimethylacetamide solvent, Slowly raise the temperature of the solvent to 120°C; when the temperature of the solvent rises to 120°C, quickly add the alkalized polyvinylidene fluoride into the solvent, keep the temperature of the casting solution at 118-122°C, and react for 3 hours. Condensation and reflux should be used during the whole process of solvent heating to heat preservation reaction for 3 hours; after heat preservation for 3 hours, the temperature of the casting solution is lowered to 40-50°C, and p-toluenesulfonic acid and ethylenediaminetetraacetic acid dianhydride are added to the above casting solution successively During the stirring reaction for 2 hours, the whole process from the addition of p-toluenesulfonic acid to the stirring reaction for 2 hours needs to be protected by nitrogen gas; after 2 hours of nitrogen gas flow, the nitrogen gas flow is stopped, and polyvinylpyrrolidone is added to the blended casting solution, stirred and dissolved, and finally Control the temperature at 70°C to 80°C and stir magnetically to dissolve and fully blend the components in the casting solution for 6 hours; after stirring for 6 hours, place the blended casting solution in a water bath for 6 to 9 hours of defoaming, and the temperature of the water bath is 50°C to 60°C;

b. The preparation process of ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride resin is as follows: add the casting liquid after degassing in step "a" into deionized water drop by drop with a dropper, and stir slowly, deionized water The electrical conductivity of the resin is 20-30μs/cm, and the water temperature is 40°C-50°C; the dropping speed of the casting liquid should not be too fast, and the next drop of casting liquid must be added after the last drop of casting liquid enters the deionized water. The average pore diameter of the micropores on the surface of the resin is 0.18μm;

c. Polyvinylidene fluoride modified with ethylenediaminetetraacetic acid dianhydride is first soaked in deionized water for 48 hours, then soaked in 0.1-0.5mol/L hydrochloric acid solution for 24 hours, taken out and washed, soaked in a water tank with a volume ratio of 0.5- Store in 2% hydrogen peroxide solution.

The present invention uses reagents such as ethylenediaminetetraacetic dianhydride, sodium hydroxide, sodium borohydride, tetrabutylammonium bromide, p-toluenesulfonic acid, N, N-dimethylacetamide as raw materials, and applies chemical blending /Phase transfer technology is also applicable to the modification of polysulfone separation membranes, polyethersulfone separation membranes, and polyacrylonitrile separation membranes.

The beneficial effects of the present invention are: the chemical graft blending/phase transfer technology of uniformly doping polyaminopolycarboxylic acid compounds with hydrophilic properties and chelating coordination properties in polyvinylidene fluoride separation membranes and resins , has the advantages of simple operation and uniform blending, improves the hydrophilic performance of conventional polyvinylidene fluoride separation membranes and resins, and realizes the removal of heavy metal pollutants in water bodies. The invention realizes the removal of polyvinylidene fluoride separation membrane and resin for complex heavy metal ions in water, improves the efficiency of polyvinylidene fluoride microfiltration separation membrane and resin for drinking water purification, and realizes the removal of heavy metal pollutants in industrial wastewater The removal and resource utilization of polyvinylidene fluoride have expanded the application of polyvinylidene fluoride separation membranes and resins in the field of water treatment.

Detailed ways

The preparation process of the EDTA-modified polyvinylidene fluoride separation membrane and resin will be described in detail below in conjunction with the examples.

Example

1. Preparation process of ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride separation membrane by chemical blending/phase transfer technology

1) Preparation of chemical solution used for alkalization of polyvinylidene fluoride:

Add 170g of sodium hydroxide and 5g of tetrabutylammonium bromide into 1L of deionized water in turn, stir to dissolve them all, and the conductivity of the deionized water is 5-10μs/cm;

2) Polyvinylidene fluoride alkalization treatment:

After all the components in the chemical alkalization solution are dissolved, the temperature is raised slowly;

When the temperature of the alkalization solution rises to 80°C, add polyvinylidene fluoride particles with an average particle size of 0.05mm and a mass of 400g into the chemical alkalization solution for alkalization, keep the solution temperature at 75-85°C, and alkalize The processing time is 8h;

After alkalization treatment for 8 hours, take out the polyvinylidene fluoride particles from the chemical alkalization solution, wash them with deionized water, and dry them at 60-80°C;

3) Preparation of the blended casting solution used in the preparation of ethylenediaminetetraacetic acid dianhydride-modified polyvinylidene fluoride separation membrane by chemical blending/phase transfer technology:

In a three-necked flask, add 0.5g of sodium borohydride to 100g of N,N-dimethylacetamide solvent, and slowly raise the temperature of the solvent to 120°C;

When the temperature of the solvent rises to 120°C, quickly add 13g of alkalized polyvinylidene fluoride into the solvent, keep the temperature of the casting solution at 118-122°C, and react for 3 hours, from the beginning of solvent heating to the heat preservation reaction for 3 hours. Condensation reflux should be used in the process;

After 3 hours of heat preservation, lower the temperature of the casting solution to 40-50°C, add 0.2g of p-toluenesulfonic acid and 180g of ethylenediaminetetraacetic dianhydride to the above casting solution, stir for 2 hours, and start adding p-toluenesulfonic acid The whole process to the stirring reaction for 2h needs nitrogen protection;

After passing nitrogen for 2 hours, stop nitrogen flow, add polyvinylpyrrolidone into the blended casting solution, stir and dissolve, finally control the temperature at 70°C to 80°C, and magnetically stir for 6 hours to dissolve and fully blend the components in the casting solution ;

After 6 hours, place the blended casting solution in a water bath for degassing for 6-9 hours, and the temperature of the water bath is 50°C-60°C;

4) Preparation of ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride separation membrane:

EDTA dianhydride modified polyvinylidene fluoride flat membrane is formed on a smooth glass with a medical scraper, and then formed in a water cooling bath; the modified hollow fiber membrane is drawn by a spinning machine, the core The liquid is 5% ethanol aqueous solution, the flow rate is 1.2-1.8mL/min; the extrusion rate of the casting solution is 1.3-1.5mL/min, and the length of the fiber filaments obtained per minute is 35 meters. The condensation bath is deionized water, and its conductivity The rate is 20~30μs/cm, and the water temperature is 40℃~50℃;

5) Handling and storage of ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride separation membrane:

EDTA dianhydride modified polyvinylidene fluoride hollow fiber membrane, flat membrane, soak in deionized water for 48 hours, then soak in 0.1-0.5mol/L hydrochloric acid solution for 24 hours, take it out and wash it, soak it in volume Store in a hydrogen peroxide aqueous solution with a ratio of 0.5 to 2%.

2. Preparation of ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride resin by chemical blending/phase transfer technology

(1) Preparation of chemical solution used for alkalization of polyvinylidene fluoride:

Add 170g of sodium hydroxide and 5g of tetrabutylammonium bromide into 1L of deionized water in turn, stir to dissolve them all, and the conductivity of the deionized water is 5-10μs/cm;

(2) Polyvinylidene fluoride alkalization treatment:

After all the components in the chemical alkalization solution are dissolved, the temperature is raised slowly;

When the temperature of the alkalization solution rises to 80°C, add polyvinylidene fluoride particles with an average particle size of 0.05mm and a mass of 400g into the chemical alkalization solution for alkalization, keep the solution temperature at 75-85°C, and alkalize The processing time is 8h;

After alkalization treatment for 8 hours, take out the polyvinylidene fluoride particles from the chemical alkalization solution, wash them with deionized water, and dry them at 60-80°C;

(3) The preparation of the blending casting solution used in the preparation of ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride resin by chemical blending/phase transfer technology:

In a three-necked flask, add 0.5g of sodium borohydride to 100g of N,N-dimethylacetamide solvent, and slowly raise the temperature of the solvent to 120°C;

When the temperature of the solvent rises to 120°C, quickly add 11g of alkalized polyvinylidene fluoride into the solvent, keep the temperature of the casting liquid at 118-122°C, and react for 3 hours, starting from the solvent and heating and keeping warm for 3 hours. Condensation reflux should be used in the process;

After keeping warm for 3 hours, lower the temperature of the casting solution to 40-50°C, add 0.2g of p-toluenesulfonic acid and 230g of ethylenediaminetetraacetic dianhydride to the above casting solution, stir for 2 hours, and start adding p-toluenesulfonic acid The whole process to the stirring reaction for 2h needs nitrogen protection;

After passing nitrogen for 2 hours, stop nitrogen flow, add polyvinylpyrrolidone into the blended casting solution, stir and dissolve, finally control the temperature at 70°C to 80°C, and magnetically stir for 6 hours to dissolve and fully blend the components in the casting solution ;

After 6 hours, place the blended casting solution in a water bath for degassing for 6-9 hours, and the temperature of the water bath is 50°C-60°C;

(4) Preparation of ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride resin:

Add the defoamed casting solution dropwise into deionized water with a dropper, and stir slowly. The conductivity of the deionized water is 20-30μs/cm, and the water temperature is 40°C-50°C;

The dripping speed of the casting solution should not be too fast, and the next drop of casting solution must be added after the last drop of casting solution enters the deionized water. The particle size of the blended microspheres is 1.2-1.7 mm, and the average pore diameter of the micropores on the resin surface is 0.18 μm;

(5) Handling and storage of ethylenediaminetetraacetic acid dianhydride modified polyvinylidene fluoride resin:

EDTA dianhydride modified polyvinylidene fluoride resin is first soaked in deionized water for 48 hours, then soaked in 0.1-0.5mol/L hydrochloric acid solution for 24 hours, taken out and washed, soaked in 0.5-2% volume ratio stored in aqueous hydrogen peroxide solution.

Claims (2)

1. the preparation technology of an ethylenediamine tetra-acetic acid dianhydride modified polyvinylidene fluoride separation membrane makes blend in the polyvinylidene fluoride separation membrane that the polyamino polycarboxylic acid functional group of chelating coordination arranged, and it is characterized in that: this preparation technology may further comprise the steps:

1) the Kynoar preparation of used chemical alkaline solution of alkalizing:

150～180g NaOH and 3～7g TBAB are joined in the 1L deionized water successively, and stirring and making its whole dissolvings, deionization electrical conductivity of water is 5～10 μ s/cm;

2) basification of Kynoar:

A. after treating that each component is all dissolved in the chemical alkaline solution; Its temperature slowly being raise, treat that temperature is increased to 80 ℃, is that 0.05mm, quality are that 400g Kynoar particle joins in the chemical alkaline solution with average grain diameter; Keeping solution temperature is 75～85 ℃, and the basification time is 8h;

B. alkalize behind the 8h, the Kynoar particle is taken out from chemical alkaline solution, it is cleaned with deionized water, dry down at 60～80 ℃;

3) adopting chemical blend/phase transfer of technology to prepare the blend casting liquid that ethylenediamine tetra-acetic acid dianhydride modified polyvinylidene fluoride separation membrane adopted consists of:

A. ethylenediamine tetra-acetic acid dianhydride 150～200g/L, sodium borohydride 4～7g/L, the Kynoar 120～150g/L of basification, p-methyl benzenesulfonic acid 1～3g/L, polyvinylpyrrolidone 30～50g/L;

B. solvent for use is N, the N-dimethylacetylamide;

C. the addition sequence of each reagent is: at first adding sodium borohydride, is the Kynoar of basification then, secondly is p-methyl benzenesulfonic acid, is ethylenediamine tetra-acetic acid dianhydride and polyvinylpyrrolidone at last successively;

4) adopt chemical blend/phase transfer of technology to prepare the preparation process of ethylenediamine tetra-acetic acid dianhydride modified polyvinylidene fluoride separation membrane:

A. adopt chemical blend/phase transfer of technology to prepare ethylenediamine tetra-acetic acid dianhydride modified polyvinylidene fluoride separation membrane, in three-neck flask, sodium borohydride is joined N, in the N-dimethylacetamide solvent, make solvent temperature slowly be increased to 120 ℃; When treating that solvent temperature is increased to 120 ℃, rapidly the Kynoar after the basification is joined in the solvent, keeping blend casting liquid temp is 118～122 ℃, and reaction 3h will adopt condensing reflux from solvent begins to be heated to the whole process of insulation reaction 3h; Behind the insulation 3h, liquid temp is cast in blend reduced to 40～50 ℃, successively p-methyl benzenesulfonic acid and ethylenediamine tetra-acetic acid dianhydride are joined in the above-mentioned blend casting liquid, stirring reaction 2h begins to join the whole process of stirring reaction 2h from p-methyl benzenesulfonic acid and need lead to nitrogen protection; After leading to nitrogen 2h, stop logical nitrogen, polyvinylpyrrolidone is joined in the blend casting liquid, stirring and dissolving is finally controlled temperature at 70 ℃～80 ℃, and magnetic agitation makes each components dissolved and abundant blend 6h in the blend casting liquid; Behind the stirring 6h liquid is cast in blend and placed water-bath deaeration 6～9h, bath temperature is 50 ℃～60 ℃;

B. ethylenediamine tetra-acetic acid dianhydride modified polyvinilidene fluoride flat sheet membrane is at the medical scraper system film of smooth usefulness on glass; Film forming in water condensation is bathed then; Ethylenediamine tetra-acetic acid dianhydride modified polyvinilidene fluoride hollow-fibre membrane is to draw with spinning-drawing machine; Core liquid is 5% ethanol water, and flow velocity is 1.2～1.8mL/min; Blend casting liquid rate of extrusion is 1.3～1.5mL/min, and the filament length that per minute makes is 35 meters, and condensation is bathed and is deionized water, and its electrical conductivity is 20～30 μ s/cm, and water temperature is 40 ℃～50 ℃;

C. ethylenediamine tetra-acetic acid dianhydride modified polyvinilidene fluoride hollow-fibre membrane and flat sheet membrane are at first soaked 48h with deionized water; Be immersed in 24h in the hydrochloric acid solution of 0.1～0.5mol/L then, taking out and being immersed in volume ratio after cleaning is to preserve in 0.5～2% the aqueous hydrogen peroxide solution.

2. the preparation technology of an ethylenediamine tetra-acetic acid dianhydride modified polyvinilidene fluoride resin makes blend in the polyvinylidene fluoride resin that the polyamino polycarboxylic acid functional group of chelating coordination arranged, and it is characterized in that: this preparation technology may further comprise the steps:

1) the Kynoar preparation of used chemical alkaline solution of alkalizing:

150～180g NaOH and 3～7g TBAB are joined in the 1L deionized water successively, and stirring and making its whole dissolvings, deionization electrical conductivity of water is 5～10 μ s/cm;

2) basification of Kynoar:

A. after treating that each component is all dissolved in the chemical alkaline solution; Its temperature slowly being raise, treat that temperature is increased to 80 ℃, is that 0.05mm, quality are that 400g Kynoar particle joins in the chemical alkaline solution with average grain diameter; Keeping solution temperature is 75～85 ℃, and the basification time is 8h;

B. alkalize behind the 8h, the Kynoar particle is taken out from chemical alkaline solution, it is cleaned with deionized water, dry down at 60～80 ℃;

3) adopting chemical blend/phase transfer of technology to prepare the blend casting liquid that ethylenediamine tetra-acetic acid dianhydride modified polyvinilidene fluoride resin adopted consists of:

A. ethylenediamine tetra-acetic acid dianhydride 180～250g/L, sodium borohydride 4～7g/L, the Kynoar 100～130g/L of basification, p-methyl benzenesulfonic acid 1～3g/L, polyvinylpyrrolidone 30～50g/L;

B. solvent for use is N, the N-dimethylacetylamide;

C. the addition sequence of each reagent is: at first adding sodium borohydride, is the Kynoar of basification then, secondly is p-methyl benzenesulfonic acid, is ethylenediamine tetra-acetic acid dianhydride and polyvinylpyrrolidone at last successively;

4) adopt chemical blend/phase transfer of technology to prepare the preparation process of ethylenediamine tetra-acetic acid dianhydride modified polyvinilidene fluoride resin:

A. adopt chemical blend/phase transfer of technology to prepare ethylenediamine tetra-acetic acid dianhydride modified polyvinilidene fluoride resin, in three-neck flask, sodium borohydride is joined N, in the N-dimethylacetamide solvent, make solvent temperature slowly be increased to 120 ℃; When treating that solvent temperature is increased to 120 ℃, rapidly the Kynoar after the basification is joined in the solvent, keeping blend casting liquid temp is 118～122 ℃, and reaction 3h will adopt condensing reflux from solvent begins to be heated to the whole process of insulation reaction 3h; Behind the insulation 3h, liquid temp is cast in blend reduced to 40～50 ℃, successively p-methyl benzenesulfonic acid and ethylenediamine tetra-acetic acid dianhydride are joined in the above-mentioned blend casting liquid, stirring reaction 2h begins to join the whole process of stirring reaction 2h from p-methyl benzenesulfonic acid and need lead to nitrogen protection; After leading to nitrogen 2h, stop logical nitrogen, polyvinylpyrrolidone is joined in the blend casting liquid, stirring and dissolving is finally controlled temperature at 70 ℃～80 ℃, and magnetic agitation makes each components dissolved and abundant blend 6h in the blend casting liquid; Behind the stirring 6h liquid is cast in blend and placed water-bath deaeration 6～9h, bath temperature is 50 ℃～60 ℃;

B. the preparation process of ethylenediamine tetra-acetic acid dianhydride modified polyvinilidene fluoride resin is: dropwise join in the deionized water with dropper the casting of the blend after the deaeration of " a " step liquid; And slowly stir; The deionization electrical conductivity of water is 20～30 μ s/cm, and water temperature is 40 ℃～50 ℃; Last blend casting liquid such as blend casting drop acceleration can not be too fast, and is necessary get in the deionized water, and could drip next drips blend casting liquid, and the granularity of resin microsphere is 1.2～1.7mm, and the average pore size of resin surface micropore is 0.18 μ m;

C. ethylenediamine tetra-acetic acid dianhydride modified polyvinilidene fluoride resin at first soaks 48h with deionized water, is immersed in 24h in the hydrochloric acid solution of 0.1～0.5mol/L then, and taking out and being immersed in volume ratio after cleaning is to preserve in 0.5～2% the aqueous hydrogen peroxide solution.