CN115252571B - A kind of porous aminated organic fluorine capsule and its preparation method and application - Google Patents

Abstract

The invention discloses a porous aminated organic fluorine capsule, which comprises a porous organic fluorine shell, wherein aminated phenolic resin is filled in the organic fluorine shell. The invention also discloses a preparation method of the porous aminated organic fluorine capsule. The invention also discloses application of the porous aminated organic fluorine capsule in adsorbing perfluorinated compounds, wherein the porous aminated organic fluorine capsule is mixed with perfluorinated compounds, and the porous aminated organic fluorine capsule is oscillated at a constant temperature of 24-26 ℃, and the mass concentration ratio of the porous aminated organic fluorine capsule material to the perfluorinated compounds is 5-100:1. The porous organic fluorine capsule material is synthesized based on common membrane materials of polyvinylidene fluoride, pore-forming agent polyvinylpyrrolidone and self-made aminated phenolic resin by a solvent substitution method, and the high-efficiency selective removal of the anionic perfluorinated compounds is successfully realized under the synergistic effect of an organic fluorine shell of the capsule and the internal aminated phenolic resin, and the raw materials are low in cost, easy to obtain and simple and convenient to prepare.

Description

A kind of porous aminated organic fluorine capsule and its preparation method and application

Technical field

The invention belongs to capsules and their preparation methods and applications, and is specifically a porous aminated organic fluorine capsule and its preparation methods and applications.

Background technique

Perfluorinated compounds (PFCs) are a new class of artificially synthesized fluorides with surfactant properties. They use an alkyl chain composed of carbon-fluorine bonds as the skeleton, and the ionic head is connected to different functional groups. The general chemical formula is F(CF ₂ ) _n -R. Since first synthesized by 3M Company in the late 1940s, PFCs have been widely used in various fields of human production and life due to their hydrophobic and lipophobic properties, high temperature resistance, and strong oxidation resistance. Studies have found that their extensive use and their strong stability make PFCs ubiquitous in the global environment, with concentrations up to 1 mg·L ^-1 in surface water and groundwater. Among the more than 3,000 PFCs put on the market, perfluorooctanoic acid (PFOA) is the most representative. It is not only produced and used in huge quantities, but also is the final product of the transformation of various PFCs in the environment and organisms, with extremely high detection frequency and concentration. PFOA in the environment mainly enters the human body through food and drinking water, and has certain teratogenic and carcinogenic effects. In the past four decades, the content of PFOA in human serum has continued to rise, with the highest concentration reaching 5 μg·L ^-1 .

In order to eliminate the adverse effects of such pollutants on the environment and organisms, a decree has been issued to restrict the sale and use of PFOA. PFOA has also been included in the priority control list of persistent organic pollutants. The health limit concentration of PFOA in drinking water is 70ng· L ^-1 . For the sake of the environment and human health, in-depth research on PFASs removal technology should be conducted.

According to relevant research, advanced reduction technology based on water and electrons and advanced oxidation technology based on sulfate radicals can effectively treat high-concentration PFOA contaminated wastewater, but the removal effect of trace amounts of PFOA in actual environmental water bodies is poor. Therefore, if you want to harmlessly treat trace amounts of PFOA in water, you must first selectively adsorb and concentrate it.

At present, the traditional adsorption technologies (activated carbon, ion exchange resin, mineral materials) already on the market have low removal efficiency for this type of pollutants and have poor anti-interference properties. Therefore, researchers have developed a series of new materials that selectively adsorb PFOA, such as covalent organofluorine framework materials (COFs) and organofluorine-modified clay minerals. However, there are still problems such as high cost, poor anti-interference performance, and easy generation of secondary pollution and other issues.

Therefore, there is an urgent need to develop an adsorbent material that is low-cost, easy to separate, and capable of selectively adsorbing trace amounts of PFOA in actual environmental water bodies.

Contents of the invention

Purpose of the invention: In order to overcome the deficiencies in the prior art, the purpose of the present invention is to provide a porous aminated organic fluorine capsule. Another purpose of the present invention is to provide a preparation method for the porous aminated organic fluorine capsule. Another purpose is to provide a porous aminated organic fluorine capsule for use in adsorbing perfluorinated compounds.

Technical solution: The porous aminated organic fluorine capsule of the present invention includes a porous organic fluorine shell, and the inside of the organic fluorine shell is filled with aminated phenolic resin.

Further, the pore diameter on the porous organic fluorine shell ranges from 28.6 to 330.5 nm, and the pore diameter decreases as the content of aminated phenolic resin in the capsule increases.

Further, the diameter of the porous aminated organic fluorine capsule is 1.5-1.8 mm.

The preparation method of the above-mentioned porous aminated organofluorine capsules includes the following steps:

S1, dissolve ethylenediamine, formaldehyde and resorcinol in the alcohol-water mixture, stir at 25-30°C, synthesize aminated phenolic resin through polymerization reaction, wash with ultrapure water, centrifuge, and heat at 90-100°C Dry for 12 to 16 hours and grind into aminated phenolic resin powder;

S2, mix polyvinylidene fluoride, polyvinylpyrrolidone and aminated phenolic resin powder, disperse in N,N-dimethylformamide solvent, and continue stirring at 50-60°C for 2-4 hours to disperse Homogenize and eliminate air bubbles to obtain a gel mixture;

S3, use a mixture of water and isopropyl alcohol as the solvent exchange liquid, and drop the gel mixture obtained in S2 into the solvent exchange liquid with a syringe while stirring at 25-30°C to obtain a half-cooked capsule;

S4: Disperse the half-cooked capsules obtained in S3 into pure water, stir and vacuum-dry at 90 to 100°C to obtain porous aminated organic fluorine capsules.

Further, in S1, the mass ratio of ethylenediamine, formaldehyde, and resorcinol is 1 to 3:1 to 3:1 to 2. In the alcohol-water mixture, the volume ratio of ethanol to water is 2:5.

Further, in S2, the mass concentration ratio of polyvinylidene fluoride, polyvinylpyrrolidone, and aminated phenolic resin powder is 12:2:4-12. The weight average molecular weight of polyvinylidene fluoride is 170,000 to 190,000. The weight average molecular weight of polyvinylpyrrolidone is 1,200,000 to 1,400,000.

Further, in S3, the volume ratio of isopropyl alcohol to water in the mixture of water and isopropyl alcohol is 30%.

The application of the above-mentioned porous aminated organic fluorine capsules in adsorbing perfluorinated compounds is to mix the porous aminated organic fluorine capsules with the perfluorinated compounds and oscillate at a constant temperature of 24 to 26°C. The mass concentration ratio is 5~100:1.

Furthermore, the pH of the porous aminated organic fluorine capsule after mixing with the perfluorinated compound is adjusted to 2 to 9.25, and the adsorption rate of the perfluorinated compound is greater than 95%.

Adsorption principle: Polyvinylidene fluoride, which has a similar structure to perfluorinated compounds, is used as the raw material to enhance the non-polar and lipophobic properties of the capsule shell, effectively eliminating the adsorption of highly polar inorganic substances such as salt ions and lipophilic organic substances such as humic substances. interference, thereby improving selectivity for perfluorinated compounds. Aminated phenolic resin can adsorb PFASs in the solution through electrostatic attraction, and the porous organic fluorine shell protects the aminated phenolic resin's adsorption of PFASs from interference.

Beneficial effects: Compared with the prior art, the present invention has the following significant features:

1. Based on the commonly used membrane material polyvinylidene fluoride, the pore-forming agent polyvinylpyrrolidone and the homemade aminated phenolic resin, the porous organic fluorine capsule material is synthesized through the solvent replacement method. The organic fluorine capsule and the internal aminated phenolic resin are used in the capsule. Under the synergistic effect, the efficient and selective removal of anionic perfluorinated compounds has been successfully achieved, and the raw materials are cheap and easy to obtain, and the preparation process is easy to operate;

2. The porous aminated organic fluorine capsule material achieves efficient and selective adsorption of perfluorinated compounds in a wide pH range, and still has good adaptability to strong acid and strong alkali environments. Even under strong alkaline conditions, The adsorption rate of perfluorinated compounds can still reach more than 95% and can be used in extreme environments;

3. The porous aminated organic fluorine capsule material maintains the particle shape of traditional commercial activated carbon and ion exchange resin without reducing the residence time of the capsule in water treatment. At the same time, the particles are large and easy to recycle;

4. It has good reusability. The capsule after adsorbing PFOA can recover its adsorption capacity through elution with methanol solution. After repeated 5 times, the adsorption amount of PFOA is almost unchanged. It has good economic applicability and a bright future.

Description of the drawings

Figure 1 is a synthesis path diagram of the present invention;

Figure 2 is a scanning electron microscope image and a size distribution chart of the present invention, where a is an electron microscope image of aminated phenolic resin under a 1 μm scale, b is an electron microscope image of aminated phenolic resin under a 200 nm scale, and c is an aminated phenolic resin. The size distribution diagram of is the electron microscopy image of AFC-1 under the 200nm scale, i is the surface pore distribution map of AFC-1, j is the electron microscopy image of AFC-2 under the 100μm scale, k is the electron microscopy image of AFC-2 under the 200nm scale, l is the surface pore distribution map of AFC-2, m is the electron microscopy image of AFC-3 under the 100 μm scale, n is the electron microscopy image of AFC-3 under the 200 nm scale, and o is the surface pore distribution map of AFC-3;

Figure 3 is a specific surface area distribution diagram of the porous aminated organic fluorine capsule material of the present invention;

Figure 4 is a schematic infrared spectrum diagram of the porous aminated organic fluorine capsule material of the present invention;

Figure 5 is a schematic diagram of the zeta potential of the porous aminated organic fluorine capsule material of the present invention;

Figure 6 is a thermodynamic diagram of the adsorption of PFOA by the porous aminated organic fluorine capsule material of the present invention, where a is the thermodynamic diagram of the adsorption of PFOA by ANP, and b is FC, AFC-1, AFC-2, AFC-3, AFC- 4. Thermodynamic diagram of adsorption of PFOA by AFC-5;

Figure 7 is a comparison chart of the adsorption effects of different adsorption materials of the present invention on PFOA;

Figure 8 is a kinetic diagram of the adsorption of different perfluorinated compounds by the porous aminated organic fluorine capsule material of the present invention;

Figure 9 is a diagram of the influence of pH on the adsorption of PFOA by porous aminated organofluorine capsule materials according to the present invention;

Figure 10 is a diagram showing the influence of coexisting substances in different environments on the adsorption of PFOA by porous aminated organofluorine capsule materials, where a is the influence diagram of AFC-2 adsorbing PFOA, and b is the influence diagram of ANP adsorbing PFOA;

Figure 11 is a recycling diagram of the porous aminated organic fluorine capsule material of the present invention.

Detailed ways

In the following examples, the weight average molecular weight of polyvinylidene fluoride is 170,000 to 190,000. The weight average molecular weight of polyvinylpyrrolidone is 1,200,000 to 1,400,000.

Example 1

As shown in Figure 1, a method for preparing porous aminated organic fluorine capsule materials includes the following steps:

S1, dissolve ethylenediamine, formaldehyde and resorcinol with a mass ratio of 1:3:2 in an alcohol-water mixture. The volume ratio of ethanol to water is 2:5. Stir at 30°C for 24 hours. Pass Aminated phenolic resin is synthesized through polymerization reaction, washed 5 times with ultrapure water, centrifuged, and the precipitate obtained after washing is dried in a 100°C blast drying oven for 12 hours and ground into aminated phenolic resin powder (ANP);

S2, mix polyvinylidene fluoride (PVDF), polyvinylpyrrolidone (PVP) and aminated phenolic resin powder (ANP). The mass concentration ratio of polyvinylidene fluoride, polyvinylpyrrolidone and aminated phenolic resin powder is 12 :2:4, dispersed in N,N-dimethylformamide solvent (DMF), stir continuously at 60°C for 2 hours to obtain a gel mixture;

S3, use a mixture of water and isopropyl alcohol as the solvent exchange solution. The volume ratio of isopropyl alcohol to water is 30%. Use a syringe to drop the gel mixture obtained in S2 into the solvent exchange solution while stirring at 25°C. , continue stirring for 2 hours to obtain half-cooked capsules;

S4: Disperse the half-cooked capsules obtained in S3 into pure water, stir for 24 hours and then vacuum dry in a vacuum drying oven at 100°C for 12 hours to obtain porous aminated organic fluorine capsules, named AFC-1.

Example 2

A method for preparing porous aminated organic fluorine capsule materials, including the following steps:

S1, dissolve ethylenediamine, formaldehyde and resorcinol with a mass ratio of 1:3:2 in an alcohol-water mixture. The volume ratio of ethanol to water is 2:5. Stir at 30°C for 24 hours. Pass Aminated phenolic resin is synthesized through polymerization reaction, washed 5 times with ultrapure water, centrifuged, and the precipitate obtained after washing is dried in a 100°C blast drying oven for 12 hours and ground into aminated phenolic resin powder;

S2, mix PVDF, PVP and ANP. The mass concentration ratio of polyvinylidene fluoride, polyvinylpyrrolidone and aminated phenolic resin powder is 12:2:6. Disperse in DMF and continue stirring at 60°C for 2 hours. Obtain gel mixture;

S3, use a mixture of water and isopropyl alcohol as the solvent exchange solution. The volume ratio of isopropyl alcohol to water is 30%. Use a syringe to drop the gel mixture obtained in S2 into the solvent exchange solution while stirring at 25°C. , continue stirring for 2 hours to obtain half-cooked capsules;

S4: Disperse the half-cooked capsules obtained in S3 into pure water, stir for 24 hours and then vacuum dry in a vacuum drying oven at 100°C for 12 hours to obtain porous aminated organic fluorine capsules, named AFC-2.

Example 3

A method for preparing porous aminated organic fluorine capsule materials, including the following steps:

S1, dissolve ethylenediamine, formaldehyde and resorcinol with a mass ratio of 1:3:2 in an alcohol-water mixture. The volume ratio of ethanol to water is 2:5. Stir at 30°C for 24 hours. Pass Aminated phenolic resin is synthesized through polymerization reaction, washed 5 times with ultrapure water, centrifuged, and the precipitate obtained after washing is dried in a 100°C blast drying oven for 12 hours and ground into aminated phenolic resin powder;

S2, mix PVDF, PVP and ANP. The mass concentration ratio of polyvinylidene fluoride, polyvinylpyrrolidone and aminated phenolic resin powder is 12:2:8. Disperse in DMF and continue stirring at 60°C for 2 hours. Obtain gel mixture;

S3, use a mixture of water and isopropyl alcohol as the solvent exchange solution. The volume ratio of isopropyl alcohol to water is 30%. Use a syringe to drop the gel mixture obtained in S2 into the solvent exchange solution while stirring at 25°C. , continue stirring for 2 hours to obtain half-cooked capsules;

S4: Disperse the half-cooked capsules obtained in S3 into pure water, stir for 24 hours and then vacuum dry in a vacuum drying oven at 100°C for 12 hours to obtain porous aminated organic fluorine capsules, named AFC-3.

Example 4

A method for preparing porous aminated organic fluorine capsule materials, including the following steps:

S1, dissolve ethylenediamine, formaldehyde and resorcinol with a mass ratio of 1:3:2 in an alcohol-water mixture. The volume ratio of ethanol to water is 2:5. Stir at 30°C for 24 hours. Pass Aminated phenolic resin is synthesized through polymerization reaction, washed 5 times with ultrapure water, centrifuged, and the precipitate obtained after washing is dried in a 100°C blast drying oven for 12 hours and ground into aminated phenolic resin powder;

S2, mix PVDF, PVP and ANP. The mass concentration ratio of polyvinylidene fluoride, polyvinylpyrrolidone and aminated phenolic resin powder is 12:2:10. Disperse in DMF and continue stirring at 60°C for 2 hours. Obtain gel mixture;

S3, use a mixture of water and isopropyl alcohol as the solvent exchange solution. The volume ratio of isopropyl alcohol to water is 30%. Use a syringe to drop the gel mixture obtained in S2 into the solvent exchange solution while stirring at 25°C. , continue stirring for 2 hours to obtain half-cooked capsules;

S4: Disperse the half-cooked capsules obtained in S3 into pure water, stir for 24 hours and then vacuum dry in a vacuum drying oven at 100°C for 12 hours to obtain porous aminated organic fluorine capsules, named AFC-4.

Example 5

A method for preparing porous aminated organic fluorine capsule materials, including the following steps:

S1, dissolve ethylenediamine, formaldehyde and resorcinol with a mass ratio of 1:3:2 in an alcohol-water mixture. The volume ratio of ethanol to water is 2:5. Stir at 30°C for 24 hours. Pass Aminated phenolic resin is synthesized through polymerization reaction, washed 5 times with ultrapure water, centrifuged, and the precipitate obtained after washing is dried in a 100°C blast drying oven for 12 hours and ground into aminated phenolic resin powder;

S2, mix PVDF, PVP and ANP. The mass concentration ratio of polyvinylidene fluoride, polyvinylpyrrolidone and aminated phenolic resin powder is 12:2:12. Disperse in DMF and continue stirring at 60°C for 2 hours. Obtain gel mixture;

S3, use a mixture of water and isopropyl alcohol as the solvent exchange solution. The volume ratio of isopropyl alcohol to water is 30%. Use a syringe to drop the gel mixture obtained in S2 into the solvent exchange solution while stirring at 25°C. , continue stirring for 2 hours to obtain half-cooked capsules;

S4: Disperse the half-cooked capsules obtained in S3 into pure water, stir for 24 hours and then vacuum dry in a vacuum drying oven at 100°C for 12 hours to obtain porous aminated organic fluorine capsules, named AFC-5.

Comparative ratio

A method for preparing porous aminated organic fluorine capsule materials, including the following steps:

S1, mix PVDF, PVP and ANP. The mass concentration ratio of polyvinylidene fluoride and polyvinylpyrrolidone is 12:2, disperse it in DMF, and continue stirring at 60°C for 2 hours to obtain a gel mixture;

S2, use a mixture of water and isopropyl alcohol as the solvent exchange solution. The volume ratio of isopropyl alcohol to water is 30%. Use a syringe to drop the gel mixture obtained in S1 into the solvent exchange solution while stirring at 25°C. , continue stirring for 2 hours to obtain half-cooked capsules;

S3: Disperse the half-cooked capsules obtained in S2 into pure water, stir for 24 hours and then vacuum dry in a vacuum drying oven at 100°C for 12 hours to obtain porous aminated organic fluorine capsules, named FC.

Test 1

The ANP obtained in S1 in Examples 1 to 5 was pasted on the scanning electron microscope sample stage with conductive glue and placed in the scanning electron microscope for photography, as shown in Figure 2. It can be concluded that ANP is a uniform microsphere with an average diameter of 225.3nm. FC containing ANP is a white sphere with a diameter of 1.8 to 2 mm, and AFC-1 to AFC-5 are yellow-brown porous spheres with a diameter of 1.5 to 1.8 mm. The FC surface contains pores with an average pore diameter of 5.4 μm. The surface of AFC-1~AFC-4 also has abundant and uniform micropores, with the pore diameter ranging from 28.6 to 330.5nm. The pore diameter decreases with the increase of ANP content in the capsule. No voids are observed on the surface of ACF-5. .

Test 2

Weigh the same mass of porous aminated organic fluorine capsules prepared in Examples 1 to 5, and select the decontrol mode on the N ₂ adsorption and desorption instrument to test the specific surface areas of different samples. The test results are shown in Figure 3. It can be concluded that the specific surface area of ANP is 178.43m ² g ^-1 , the specific surface area of FC is 98.89m ² g ^-1 , and the ratio of AFC-1, AFC-2, AFC-3, AFC-4 and AFC-5 The surface areas are 132.96, 160.50, 155.22, 144.63 and 128.88m ² g ^-1 respectively. The specific surface area first increases and then decreases with the increase of ANP content in the capsule, among which AFC-2 has the largest specific surface area.

Test 3

Select powdered ANP, single particle FC and AFC, use multiple attenuated total reflection (ATR) mode, and directly test the infrared signal of the selected sample on the solid sample stage. The data is shown in Figure 4.

It can be concluded that the signals of methylene (-CH ₂ -) stretching vibration at 2853.4 and 2925.6 cm ^-1 come from ANP, and different porous aminated organic fluorine capsules have stronger signals here, and then As the ANP content increases, the signal gradually increases, indicating that the ANP content in the capsule gradually increases. 1604.3cm ^-1 is the bending vibration signal of the NH bond in the amino group. The strong signal of ANP here indicates that it contains rich amino groups. The signals of different porous aminated organic fluorine capsules here increase with the increase of ANP content. Enhancement also indicates an increasing amount of amino acids in the capsule.

Test 4

The porous aminated organofluorine capsules are characterized by a zeta potential meter. The specific steps are:

(1) Prepare respectively FC (obtained in Comparative Example) and ANP solution (obtained in Example 1) containing 1g·L ^-1 , and use NaOH of different concentrations to adjust the pH of the reaction solution to 2 to 11;

(2) Use a zeta potential meter to measure the zeta potential of the solution obtained in step (1).

It can be concluded that the isoelectric points of ANP and FC are 9.25 and 6.88 respectively, which means that ANP can attract anionic perfluorinated compounds through electrostatic interaction in a wide pH range (pH=2~9.25). .

Test 5

To investigate the adsorption thermodynamics of PFOA by porous aminated organofluorine capsules, the specific steps are:

(1) Prepare 6 groups of PFOA solutions with initial concentrations of 10 to 200 mg·L ^-1 and 1 group of 5 mL of PFOA solutions with initial concentrations of 10 to 900 mg L ^-1 . Use NaOH of different concentrations to adjust the pH of the reaction solution to 6, and add 5 mg of FC and AFC- 1. AFC-2, AFC-3, AFC-4, AFC-5 and ANP are sealed and oscillated using a constant temperature oscillation box. The reaction temperature is controlled at 25±1°C. After 1 hour, two portions of the supernatant are taken out as parallel Samples were tested for PFOA concentration.

(2) Use the langmuir model to fit the adsorption isotherm of _{PFOA .} The model _is Q _e = ₍ K _L The maximum adsorption capacities on 1 to AFC-5 are 0.64837, 0.00031, 0.01038, 0.04559, 0.04013, 0.03322, and 0.02278mgmg ^-1 respectively. The specific results are shown in Figure 7.

It can be concluded from this that ANP has a very strong adsorption capacity for PFOA, and capsules without amination cannot adsorb PFOA; capsules with different raw material ratios have different adsorption effects on PFOA. The general rule is that as the ANP content increases, the capsules have different adsorption effects on PFOA. The adsorption efficiency first increased and then decreased. Among them, AFC-2 has the best adsorption effect on PFOA.

Test 6

To investigate the adsorption of PFOA by the porous aminated organic fluorine capsule AFC-2 with the strongest adsorption capacity and other adsorbent materials, the specific steps are:

(1) Prepare 5 mL of PFOA solution containing 1 μgL ^-1 , and adjust the pH of the reaction solution to 6 with different concentrations of NaOH;

(2) Add 5 mg of AFC-2, FC, ANP and powdered activated carbon to the solution obtained in step (1) respectively. After sealing, use a constant temperature oscillation box to oscillate. The reaction temperature is controlled at 25±1°C and the reaction time is 5 hours. . The sampling times are set to 0, 0.1, 0.3, 0.6, 1, and 5h respectively. At each time point, two portions of the supernatant were taken as parallel samples to measure the adsorption rate of PFOA, as shown in Figure 7.

It can be concluded from this that powdered activated carbon and FC can hardly adsorb PFOA, while AFC-2 and ANP have better adsorption effects on PFOA, and can reduce the concentration of 1μgL ^-1 PFOA to less than 70ngL ^-1 within the first hour. .

Test 7

Examine the adsorption kinetics of different perfluorinated compounds by porous aminated organofluorine capsules. The specific steps are:

(1) Prepare respectively trifluoroacetic acid (TFA), perfluorobutyric acid (PFBA), perfluorohexanoic acid (PFHxA), PFOA, perfluorooctane sulfonic acid (PFOS), and hexafluoropropylene oxide containing 1 μgL ^-1 5 mL of trimer acid (HFPO-TA) and perfluorosuberic acid (PFdiCA) solutions, use different concentrations of NaOH to adjust the pH of the reaction solution to 6;

(2) Add 5 mg of AFC-2 to the solution obtained in step (1), seal and oscillate using a constant temperature oscillation box, control the reaction temperature at 25±1°C, and take out two portions of the supernatant after 1 hour as Parallel samples were used to determine adsorption efficiency.

It can be concluded from this that porous aminated organofluorine capsules have different adsorption effects on different perfluorinated compounds. The adsorption effect on PFOA, PFOS and HFPO-TA is the best, with an adsorption rate of more than 98%; on TFA and PFdiCA The adsorption effect is average.

Test 8

To investigate the effect of pH on the adsorption of perfluorinated compounds by porous aminated organofluorine capsules, the specific steps are:

(1) Prepare 5 mL of PFOA solution containing 1 μgL ^-1 , and use different concentrations of NaOH to adjust the pH of the reaction solution to 2, 4, 6, 8, and 10;

(2) Add 5 mg of AFC-2 and ANP respectively to the solution obtained in step (1), seal and oscillate using a constant temperature oscillation box, control the reaction temperature at 25±1°C, and take out two portions of the supernatant after 1 hour The liquid was used as a parallel sample to measure the adsorption efficiency.

It can be concluded that when pH<8, pH has almost no impact on the adsorption process of PFOA by AFC-2 and ANP, while when pH>8, pH has a greater impact on the adsorption process of PFOA by ANP and has a greater impact on AFC-2. The process of adsorbing PFOA has less impact.

Test 9

The environmental coexisting substances humic substances (humic acid (SRHA), fulvic acid (SRFA)), small molecular acids (oxalic acid (OA), benzoic acid (BA)), and salt ions (sodium chloride (NaCl), calcium chloride ( The effect of CaCl ₂ )) on the adsorption of perfluorinated compounds by porous aminated organofluorine capsules. The specific steps are:

(1) Prepare 5 mL of solutions containing 1 μgL ^-1 PFOA and different concentrations of environmental coexisting substances (5 mgL ^-1 SRHA, SRFA, 5 mgL ^-1 NaCl, CaCl ₂ , 10mMOA, BA), and adjust the pH of the reaction solution to 6;

(2) Add 5 mg of AFC-2 and ANP respectively to the solution obtained in step (1), seal and oscillate using a constant temperature oscillation box, control the reaction temperature at 25±1°C, and take out two portions after 1 and 5 hours. The supernatant was used as a parallel sample to determine the adsorption efficiency. )

It can be concluded that humic substances (SRHA, SRFA), small molecular acids (OA, BA) and salt ions (NaCl, CaCl ₂ ) have a greater impact on the adsorption process of PFOA by ANP and have a greater impact on the adsorption process of PFOA by AFC-2. Less affected.

Test 10

To investigate the recycling and regeneration ability of porous aminated organofluorine capsules, the specific steps are:

(1) Place the adsorbed saturated porous aminated organic fluorine capsule in 5 mL of methanol, seal it and oscillate it in a constant temperature oscillation box, and control the reaction temperature at 25±1°C. After 10 hours, two portions of the supernatant were taken out as parallel samples to measure the desorption efficiency.

(2) Take out the desorbed porous aminated organofluorine capsules, wash, dry and re-adsorb 1 μgL ^-1 PFOA. Repeat the above desorption process 5 times to comprehensively evaluate the recycling efficiency of the capsule material.

From this, it can be concluded that porous aminated organofluorine capsules have strong recycling and regeneration capabilities, and their adsorption capacity for PFOA remains almost unchanged after five adsorption-desorption cycles.

Example 6

A method for preparing porous aminated organic fluorine capsule materials, including the following steps:

S1, dissolve ethylenediamine, formaldehyde and resorcinol in a mass ratio of 1:1:1 in an alcohol-water mixture. The volume ratio of ethanol to water is 2:5, and stir at 25-30°C for 24 hours. , synthesize aminated phenolic resin through polymerization reaction, wash with ultrapure water 5 times, centrifuge, and the precipitate obtained after washing is dried in a 90°C blast drying oven for 12 hours, and ground into aminated phenolic resin powder;

S2, mix PVDF, PVP and ANP, disperse in DMF, and continue stirring at 50°C for 2 hours to obtain a gel mixture;

S3, use a mixture of water and isopropyl alcohol as the solvent exchange solution. The volume ratio of isopropyl alcohol to water is 30%. Use a syringe to drop the gel mixture obtained in S2 into the solvent exchange solution while stirring at 25°C. , continue stirring for 2 hours to obtain half-cooked capsules;

S4: Disperse the half-cooked capsules obtained in S3 into pure water, stir for 24 hours, and then vacuum-dry in a vacuum drying oven at 90°C for 12 hours to obtain porous aminated organic fluorine capsules.

Example 7

A method for preparing porous aminated organic fluorine capsule materials, including the following steps:

S1, dissolve ethylenediamine, formaldehyde and resorcinol with a mass ratio of 3:3:2 in an alcohol-water mixture. The volume ratio of ethanol to water is 2:5, and stir at 25-30°C for 24 hours. , synthesize aminated phenolic resin through polymerization reaction, wash with ultrapure water 5 times, centrifuge, and the precipitate obtained after washing is dried in a 100°C blast drying oven for 16 hours, and ground into aminated phenolic resin powder;

S2, mix PVDF, PVP and ANP, disperse in DMF, and stir continuously at 60°C for 4 hours to obtain a gel mixture;

S3, use a mixture of water and isopropyl alcohol as the solvent exchange solution. The volume ratio of isopropyl alcohol to water is 30%. Use a syringe to drop the gel mixture obtained in S2 into the solvent exchange solution while stirring at 30°C. , continue stirring for 2 hours to obtain half-cooked capsules;

S4: Disperse the half-cooked capsules obtained in S3 into pure water, stir for 24 hours, and then vacuum-dry in a vacuum drying oven at 100°C for 12 hours to obtain porous aminated organic fluorine capsules.

Example 8

A method for preparing porous aminated organic fluorine capsule materials, including the following steps:

S1, dissolve ethylenediamine, formaldehyde and resorcinol with a mass ratio of 2:2:1 in an alcohol-water mixture. The volume ratio of ethanol to water is 2:5, and stir at 25-30°C for 24 hours. , synthesize aminated phenolic resin through polymerization reaction, wash with ultrapure water 5 times, centrifuge, and the precipitate obtained after washing is dried in a 95°C blast drying oven for 14 hours, and ground into aminated phenolic resin powder (ANP);

S2, mix PVDF, PVP and ANP, disperse in DMF, and continue stirring at 55°C for 3 hours to obtain a gel mixture;

S3, use a mixture of water and isopropyl alcohol as the solvent exchange liquid. The volume ratio of isopropyl alcohol to water is 30%. Use a syringe to drop the gel mixture obtained in S2 into the solvent exchange liquid while stirring at 27°C. , continue stirring for 2 hours to obtain half-cooked capsules;

S4: Disperse the half-cooked capsules obtained in S3 into pure water, stir for 24 hours, and then vacuum-dry in a vacuum drying oven at 95°C for 12 hours to obtain porous aminated organic fluorine capsules.

Claims (9)

1. A porous aminated organic fluorine capsule, characterized in that: it includes a porous organic fluorine shell, and the inside of the organic fluorine shell is filled with aminated phenolic resin; The preparation method of the porous aminated organofluorine capsule includes the following steps: S1, dissolve ethylenediamine, formaldehyde and resorcinol in the alcohol-water mixture, stir at 25~30℃, synthesize aminated phenolic resin through polymerization reaction, wash with ultrapure water, centrifuge, and heat at 90~100℃ Dry for 12~16 hours and grind into aminated phenolic resin powder; S2, mix polyvinylidene fluoride, polyvinylpyrrolidone and aminated phenolic resin powder, disperse in N, N-dimethylformamide solvent, and continue stirring at 50~60°C for 2~4 hours to obtain a gel state mixture; S3, use a mixture of water and isopropyl alcohol as the solvent exchange liquid, and drop the gel mixture obtained in S2 into the solvent exchange liquid while stirring at 25~30°C to obtain a half-cooked capsule; S4: Disperse the half-cooked capsules obtained in S3 into pure water, stir and vacuum-dry at 90~100°C to obtain porous aminated organic fluorine capsules. 2. A porous aminated organic fluorine capsule according to claim 1, characterized in that: the pore diameter on the porous organic fluorine shell is 28.6 ~ 330.5 nm, and the pore diameter increases with the content of aminated phenolic resin in the capsule And decrease. 3. A porous aminated organic fluorine capsule according to claim 1, characterized in that: the diameter of the porous aminated organic fluorine capsule is 1.5 ~ 1.8 mm. 4. A kind of porous aminated organic fluorine capsule according to claim 1, characterized in that: in the S1, the mass ratio of ethylenediamine, formaldehyde and resorcinol is 1~3:1~3:1 ~2. 5. A porous aminated organic fluorine capsule according to claim 1, characterized in that: in the S2, the mass concentration ratio of polyvinylidene fluoride, polyvinylpyrrolidone, and aminated phenolic resin powder is 12:2. :4~12. 6. A porous aminated organic fluorine capsule according to claim 1, characterized in that: in the S2, the weight average molecular weight of polyvinylidene fluoride is 170000~190000. 7. A porous aminated organic fluorine capsule according to claim 1, characterized in that: in the S2, the weight average molecular weight of polyvinylpyrrolidone is 1,200,000~1,400,000. 8. The application of a porous aminated organic fluorine capsule in adsorbing perfluorinated compounds according to any one of claims 1 to 3, characterized in that: the porous aminated organic fluorine capsule is mixed with the perfluorinated compound, and the mixture is mixed at 24 to Constant temperature oscillation at 26°C, the mass concentration ratio between the porous aminated organic fluorine capsule material and the perfluorinated compound is 5 to 100:1. 9. The application of a porous aminated organic fluorine capsule in adsorbing perfluorinated compounds according to claim 8, characterized in that: the pH after mixing the porous aminated organic fluorine capsule and the perfluorinated compound is adjusted to 2~ 9.25, the adsorption rate of perfluorinated compounds is greater than 95%.