CN108483613B

CN108483613B - Hydrophilic material doped blending membrane loaded nano zero-valent iron composite material and preparation method and application thereof

Info

Publication number: CN108483613B
Application number: CN201810351614.2A
Authority: CN
Inventors: 王向宇; 汪滔
Original assignee: Kunming University of Science and Technology
Current assignee: Kunming University of Science and Technology
Priority date: 2018-04-19
Filing date: 2018-04-19
Publication date: 2021-05-14
Anticipated expiration: 2038-04-19
Also published as: CN108483613A

Abstract

The invention discloses a hydrophilic material doped blending membrane loaded nano zero-valent iron composite material and a preparation method and application thereof, wherein the method comprises the following steps: (1) synthesizing a hydrophilic material; (2) doping hydrophilic materials in the synthetic process of the blend membrane; (3) soaking the hydrophilic material doped blend membrane into a bio-excitation polymer solution for functionalization; (4) immersing the functionalized hydrophilic material doped blending membrane into a soluble iron salt solution to load iron ions on the boehmite doped blending membrane; (5) then immersing the blending membrane loaded with iron ions into a borohydride solution, and forming a hydrophilic material doped blending membrane loaded with the nano zero-valent iron composite material through strong reduction; the method has the advantages of low cost, simple and convenient operation process, good dispersion property of the prepared nano zero-valent iron particles, high reaction activity, easy recovery, good removal capability of heavy metals, organic dyes and antibiotic wastewater, no secondary pollution and wide application prospect in the field of environmental pollution remediation.

Description

Hydrophilic material doped blending membrane loaded nano zero-valent iron composite material and preparation method and application thereof

Technical Field

The invention belongs to a preparation and modification technology of a nano material, and relates to a hydrophilic material doped blending membrane loaded nano zero-valent iron composite material and a preparation method thereof, and the composite material is applied to the treatment of wastewater containing pollutants such as heavy metals, dyes, antibiotics and the like.

Background

Since the end of the 80's of the 20 th century, nano zero-valent iron, as a novel nano material, has shown superior removal and degradation properties in the aspects of contaminated soil and water body remediation, and has received wide attention in the fields of environmental science and engineering. The particle size of the nano zero-valent iron particles is 1-100 nm, and compared with common nano iron particles, the nano zero-valent iron particles have the characteristics of large specific surface area and high reaction activity due to the unique small-size effect, and further have excellent adsorption performance and reduction performance. The nano zero-valent iron technology is one of the most potential environmental pollution remediation technologies at present, provides a new idea and a new method for further environmental pollution remediation and environmental pollution mechanism research, has the characteristics of low price and environmental friendliness, and is widely applied to removal of various environmental pollutants such as heavy metal ions, dyes, antibiotics, halogenated organic matters and the like.

At present, the preparation method of nano zero-valent iron at home and abroad generally adopts a liquid phase reduction method, and the method is widely used due to simple equipment, easy operation and low production cost. However, the nano zero-valent iron prepared by the liquid phase reduction method has the problems of uneven particle size distribution, easy agglomeration, reduced activity and the like, so that the engineering application of the nano zero-valent iron technology in the field of environmental pollution remediation also has some technical barriers. To deal with these problems, many researchers in the related field propose various methods for treating and modifying nano zero-valent iron, including: (1) physical methods such as ultrasound, microwave, etc.; (2) modified by a dispersant, wherein the commonly used dispersant comprises polyacrylic acid, polyvinylpyrrolidone, polymethyl methacrylate and the like; (3) the nano iron is loaded, fixed and dispersed to prevent agglomeration, and common carriers comprise bentonite, pumice, active carbon, organic polymer carriers and the like. Compared with inorganic carriers, organic polymer carriers are often used for loading nano materials to synthesize composite materials due to controllable porous structures and superior surface chemical properties of the organic polymer carriers, and the newly prepared composite materials couple the respective superior properties of nano iron particles and organic polymer carrier materials into a whole, so that the repeated use of nano zero-valent iron is realized. The literature reports that nano zero-valent iron particles are successfully loaded on polymer membranes such as polyether sulfone and polyvinylidene fluoride, and experimental results show that the agglomeration of the nano zero-valent iron particles loaded on the membranes is greatly weakened and the dispersibility is improved, so that the reactivity and the degradation performance of the nano zero-valent iron particles on pollutants are greatly improved. Although some documents report that the dispersant can have a certain effect on the modified nano zero-valent iron particles, the nano zero-valent iron modified by the dispersant still exists in a water body in the form of particles, and the nano iron particles can migrate along with the flow of the water body, so that the nano iron particles are difficult to recover and pose potential risks to the ecological environment.

Therefore, the preparation of the nanometer zero-valent iron-based composite material with simple synthesis process, high reaction activity and recoverable performance is very important.

In order to meet the requirement, the PVDF and PVB synthesized blend membrane is used as a carrier to load the nano zero-valent iron to synthesize the composite material, so that the agglomeration of nano zero-valent iron particles is weakened, the dispersity is improved, the reaction activity and the degradation performance are improved, and the recycling of the nano zero-valent iron particles is realized. The PVDF film is a microporous high molecular polymer film, and has excellent physicochemical properties such as strong acid and alkali resistance, high mechanical properties, high temperature resistance and the like, but the PVDF film has extremely strong hydrophobicity, so that the problems that the PVDF film is easy to block film pores, the film is easy to pollute and difficult to hydrophilize and the like can be caused in practical application, besides, the PAN film is also used for loading nano zero-valent iron and has the problems, although the problems are improved by utilizing the blending of PVB, PVDF and PAN to form the film, other methods are still needed to further solve the problems. At present, no literature provides a scheme which is simple and easy to operate for hydrophilic modification of PVDF and PAN hydrophobic membranes. According to the invention, a hydrophilic blended membrane is synthesized by doping synthesized hydrophilic materials with PVDF/PVB and PAN/PVB for the first time, then a biological excitation polymer (dopamine and levodopa) is coated on the surface of the membrane, the hydrophilicity of the blended membrane is greatly improved by utilizing the polyhydroxy structure of the hydrophilic materials, and the synthesized PVDF/PVB blended membrane and PAN/PVB blended membrane with-OH functional groups on the surfaces provide reaction medium conditions for the subsequent synthesis of hydrophilic material doped PVDF/PVB blended membrane loaded nano zero-valent iron composite materials and PAN/PVB blended membrane loaded nano zero-valent iron composite materials. The results of literature search show that the same report as the present invention is not found.

Disclosure of Invention

The invention aims to provide a preparation method of a hydrophilic material doped blending film loaded nano zero-valent iron composite material with good dispersibility and recyclability, and the method is to use nano boehmite and polyaniline to wrap boehmite/Fe₃O₄Or boehmite/Fe₃O₄Wrapping a hydrophilic blending membrane which is prepared by compounding carbon nanowires and is provided with-OH functional groups on the surface and is prepared by doping PVDF/PVB or PAN/PVB, soaking the hydrophilic blending membrane doped with hydrophilic materials into a solution of a bio-excitation polymer (dopamine and levodopamine) for functionalization, and then synthesizing the hydrophilic blending membrane doped with PVDF/PVB or the PAN/PVB blending membrane loaded with nano zero-valent iron composite material. The functional material prepared by the method can solve the problems that the nano zero-valent iron is easy to agglomerate and volatilize, and the nano particles are easy to lose and possibly cause secondary pollution when being directly applied to polluted water bodies, can improve the reaction activity and the degradation performance of the nano zero-valent iron, and provides a new technical method for removing the pollution of heavy metal ions, dyes, antibiotics and the like in water.

The specific technical scheme of the invention is as follows:

(1) according to the volume ratio of 1: 1-2, titrating NaOH solution to Al (NO) at constant speed₃)₃In the solution, continuously stirring in the titration process to uniformly mix and react, carrying out ultrasonic treatment on a milky mixture obtained after the reaction at the temperature of 20-25 ℃ for 3 hours, taking out, then placing at the temperature of 200-220 ℃ for vacuum drying, taking out and grinding into powder to obtain nano boehmite;

(2) mixing the product obtained in the step (1) with PVDF-PVB powder or PAN-PVB powder, then placing the mixture into a solvent to prepare a membrane casting solution, and stirring the solution for 24-48 hours to prepare a blended membrane, wherein the mass concentration of the product obtained in the step (1) in the membrane casting solution is 0.5-4%, and the mass concentration of the PVDF-PVB powder or PAN-PVB powder in the membrane casting solution is 18-25%;

(3) dissolving tris (hydroxymethyl) aminomethane and hydrochloric acid into an ethanol aqueous solution, oxidizing for 15min to obtain 1.0-2.0 g/L of a Tric-HCl solution, adjusting the pH value of the solution to 8.5-10, dissolving dopamine and levodopa into the Tric-HCl solution to obtain a solution with the concentration of 2.0-3.0 g/L, soaking the blend membrane obtained in the step (2) into the dopamine and levodopa solution at 25-35 ℃ for 15-20 h, stirring continuously during the soaking period, taking out the blend membrane, and washing the blend membrane with deionized water for 2-3 times, wherein the ethanol aqueous solution is prepared by mixing water and ethanol according to the volume ratio of 8: 2-7: 3, the mass ratio of tris (hydroxymethyl) aminomethane to hydrochloric acid is 1: 1-3: 1, and the mass ratio of levodopa to dopamine is 3: 7-7: 3;

(4) soaking the blend membrane washed in the step (3) in an iron salt solution for 12-24 h, and washing with deionized water for 2-3 times;

(5) and (4) soaking the blend membrane washed in the step (4) in a borohydride solution for 30-60 min, taking out, and sequentially washing with deionized water and absolute ethyl alcohol for 2-3 times to obtain the hydrophilic material doped blend membrane loaded nano zero-valent iron composite material.

After the nano boehmite is prepared in the step (1), FeSO₄、FeCl₃And FeCl₂Dissolving the mixture in deionized water according to the molar ratio of (1-2) to (3-5) to (1-2) to obtain an iron salt solution, and adjusting the pH value of the iron salt solution to 9 ∞After 11, titrating by using ammonium hydroxide solution to form black precipitate which is Fe₃O₄Particles of Fe₃O₄Washing the particles with ethanol and deionized water respectively, drying, and mixing with nanometer boehmite and Fe₃O₄Putting the particles and aniline in a mass ratio of (1-2) to (2-5) into hydrochloric acid solution containing aniline, performing ultrasonic treatment for 15-20 min, adding ammonium sulfate solution, and reacting for 60-120 min to obtain polyaniline-coated boehmite/Fe₃O₄Cleaning and drying, wherein the aniline-containing hydrochloric acid solution is prepared by mixing aniline and 0.1mol/L hydrochloric acid solution according to the volume ratio of 3: 40-50, and the molar ratio of ammonium sulfate to aniline is 1-2: 1; then coating the polyaniline with boehmite/Fe₃O₄Mixing with PVDF-PVB powder or PAN-PVB powder to obtain polyaniline-coated boehmite/Fe₃O₄The doped PVDF/PVB (PAN/PVB) blend membrane carries the nano zero-valent iron composite material.

Or after the nano boehmite is prepared in the step (1), FeSO is added₄、FeCl₃And FeCl₂Dissolving the raw materials in deionized water according to a molar ratio of (1-2) to (3-5) to (1-2) to prepare an iron salt solution with the iron ion concentration of 0.5-1 mol/L, adjusting the pH value of the iron salt solution to 9-11, putting the carbon nanowires into the deionized water for ultrasonic treatment, taking out the carbon nanowires and the nano boehmite, adding the carbon nanowires and the nano boehmite into 15-20 mL of the iron salt solution, titrating with an ammonium hydroxide solution to form a black precipitate, namely boehmite/Fe₃O₄Wrapping the carbon nano-wire, cleaning and drying; wherein the adding amount of the carbon nano-wires is 0.5-2 g, the adding amount of the nano-boehmite is 0.1-0.3 g, and then the boehmite/Fe is added₃O₄The wrapped carbon nano-wires are mixed with PVDF-PVB powder or PAN-PVB powder, and the subsequent steps are completed to obtain the boehmite/Fe₃O₄The carbon nanowire-coated PVDF/PVB (PAN/PVB) blended film carries the nano zero-valent iron composite material.

The titration in the step (1) is carried out at the temperature of 5-40 ℃. The preparation of boehmite to a nano-scale size is facilitated at this temperature.

The concentration of the NaOH solution in the step (1) is 0.5-3 mol/L; al (NO)₃)₃The concentration of the solution is 0.1 mol/L-1 mol/L.

The concentration of iron ions in the iron salt solution in the step (2) is 1-4 mol/L.

The solvent in the step (3) is dimethylacetamide.

The PVDF-PVB powder is prepared by mixing polyvinylidene fluoride and polyvinyl butyral according to the mass ratio of 3: 7-7: 3; the PAN-PVB powder is prepared by mixing polyacrylonitrile and polyvinyl butyral according to the mass ratio of 3: 7-7: 3.

The ferric salt solution in the step (5) is FeSO with the concentration of 0.1 mol/L-1 mol/L₄The pH value of the solution is 3-5.

The solution of borohydride salt in the step (6) is sodium borohydride or potassium borohydride solution with the concentration of 0.2-4 mol/L.

The invention also aims to provide the hydrophilic material doped blended membrane loaded nano zero-valent iron composite material prepared by the method, and the composite material consists of the hydrophilic material doped blended membrane and nano zero-valent iron particles on the loaded membrane.

The invention applies the hydrophilic material doped blending membrane loaded nano zero-valent iron composite material to the removal of heavy metal ions, dyes, antibiotics and chlorinated organic compounds in wastewater.

Compared with unmodified nano zero-valent iron particles, the hydrophilic material doped blending membrane loaded nano zero-valent iron composite material synthesized by the invention has higher dispersity and degradation performance.

The invention has the beneficial effects that:

(1) the method solves the problems that nano zero-valent iron particles are easy to agglomerate and are easy to lose when being directly applied to repairing water body pollution, and obtains a nano zero-valent iron-based composite material which has high dispersibility and can be recycled;

(2) compared with unmodified nano zero-valent iron, the material synthesized by the method has the advantages that the dispersibility is greatly improved, the reaction activity is obviously improved, and the material can be recycled;

(3) the raw materials used in the invention have low cost, and the synthesis process of the nano zero-valent iron-based composite material is simple and convenient to operate, is suitable for large-scale process production, and has good application prospect;

(4) the material synthesized by the method can effectively remove heavy metal ions, dyes, antibiotics and chlorinated organic compounds in the wastewater;

(5) the synthetic material is easy to recover, potential ecological risks caused by loss of the nano particles directly entering a water body are reduced, the service cycle of the composite material is further prolonged, and the environmental remediation cost is reduced.

Drawings

FIG. 1 is a Scanning Electron Microscope (SEM) image of a PVDF/PVB blend film before and after doping with boehmite, wherein (a) is a PVDF/PVB film that is not doped with nano-boehmite; (b) is a PVDF/PVB film doped with nano-boehmite; (c) is SEM picture of the boehmite doped PVDF/PVB blended membrane loaded nano zero-valent iron composite material;

FIG. 2 is a schematic diagram showing the comparison of the performance of the hydrophilic material doped PVDF/PVB blended film loaded nano zero-valent iron composite material prepared in example 1 of the present invention and common unmodified nano zero-valent iron for removing Cr (VI) in water;

fig. 3 is a comparison diagram of performance of the hydrophilic material doped PAN/PVB blend film loaded nano zero-valent iron composite material prepared in example 2 of the present invention and common unmodified nano zero-valent iron for removing orange ii in water.

Detailed Description

The invention will be further explained in more detail below with reference to embodiments by means of the drawing, without limiting the scope of the invention thereto.

Example 1: nano zero-valent iron composite material carried by boehmite-doped PVDF/PVB blended film and polyaniline-coated boehmite/Fe₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The preparation method of the carbon nanowire-coated PVDF/PVB blended film loaded nano zero-valent iron-loaded composite material and the method for removing Cr (VI) in water specifically comprise the following steps:

1. the preparation of common unmodified nano zero-valent iron particles and the removal effect of the particles on Cr (VI) in water are as follows:

(1) measuring 100mL KBH with concentration of 1mol/L under the nitrogen protection environment₄The solution is added dropwise with 100mL FeSO with the concentration of 1mol/L₄In the solution, continuously stirring uniformly by a magnetic stirrer in the process until the reaction is finished, passing the solution after the reaction through a Buchner funnel with a 0.22 micron microporous filter membrane, washing the solution by deionized water for 3 times, then carrying out suction filtration till the solution is dry, soaking the obtained solid particles into 50mL of absolute ethyl alcohol, stirring and soaking for 5min, filtering the solution by a sand core filtering device, sequentially washing the solution by the absolute ethyl alcohol and acetone for 2 times, draining the solution, putting the nano zero-valent iron particles into a dryer for 5 days, grinding, and sealing and storing to obtain common unmodified nano zero-valent iron particles;

(2) at room temperature, 0.05g of ordinary unmodified nano zero-valent iron particles are put into 100mL of Cr (VI) solution, the initial concentration of the Cr (VI) is 20mg/L, the initial pH value of the reaction solution is 5, the concentration of the Cr (VI) is measured after 90min of reaction is finished, and the removal rate is calculated. The removal rate was 67.73%.

2. Nano zero-valent iron composite material carried by boehmite-doped PVDF/PVB blended film and polyaniline-coated boehmite/Fe₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The preparation of the carbon nanowire-coated PVDF/PVB blended film-doped nano zero-valent iron-loaded composite material and the effect of the composite material on removing Cr (VI) in water are as follows:

(1) titrating 0.5mol/L NaOH solution to 0.1mol/L Al (NO) at a constant speed at 5 DEG C₃)₃In the solution (volume ratio is 1: 1), continuously mechanically stirring in the titration process to uniformly mix and react, carrying out ultrasonic treatment on a milky mixture obtained after the reaction at 25 ℃ for 3 hours, taking out, then placing at 220 ℃ for vacuum drying, taking out and grinding into powder to obtain the nano boehmite;

mixing nano boehmite with PVDF-PVB powder (prepared by mixing polyvinylidene fluoride and polyvinyl butyral according to the mass ratio of 3: 7), then putting the mixture into a DMAc solvent to prepare a membrane casting solution, stirring the solution for 24 hours, and preparing a 4cm multiplied by 4mm size blend membrane, wherein the mass concentration of the nano boehmite in the membrane casting solution is 0.5%, and the mass concentration of the PVDF-PVB powder in the membrane casting solution is 18%;

(2) FeSO (ferric oxide) is added₄、FeCl₃And FeCl₂Dissolved in deionized water according to the molar ratio of 1:3:1Preparing 1mol/L ferric salt solution in water, adjusting the pH value of the ferric salt solution to 10, titrating by using ammonium hydroxide solution to form black precipitate which is Fe₃O₄Particles of Fe₃O₄Washing the particles with ethanol and deionized water respectively, drying, and mixing with nanometer boehmite and Fe₃O₄Putting the particles and aniline into hydrochloric acid solution containing aniline according to the mass ratio of 1: 1:2, performing ultrasonic treatment for 15min, adding ammonium sulfate solution, and reacting for 60min to obtain polyaniline-coated boehmite/Fe₃O₄Washing and drying, wherein the aniline-containing hydrochloric acid solution is prepared by mixing aniline and 0.1mol/L hydrochloric acid solution according to the volume ratio of 3:50, and the molar ratio of ammonium sulfate to aniline is 1: 1;

coating boehmite/Fe with polyaniline₃O₄Mixing with PVDF-PVB powder (prepared by mixing polyvinylidene fluoride and polyvinyl butyral according to the mass ratio of 3: 7), adding into solvent to prepare membrane casting solution, stirring the solution for 24h, and preparing into a 4cm × 4cm × 4 mm-sized blend membrane, wherein boehmite/Fe is wrapped by polyaniline₃O₄The mass concentration of the PVDF-PVB powder in the membrane casting solution is 0.5 percent, and the mass concentration of the PVDF-PVB powder in the membrane casting solution is 18 percent;

(3) FeSO (ferric oxide) is added₄、FeCl₃And FeCl₂Dissolving the carbon nano wires in deionized water according to the mol ratio of 1:3:1 to prepare ferric salt solution with the ferric ion concentration of 0.5mol/L, adjusting the pH value of the ferric salt solution to 10, putting the carbon nano wires into the deionized water for ultrasonic treatment, taking out the carbon nano wires and the nano boehmite, adding the carbon nano wires and the nano boehmite into 20mL of the ferric salt solution, titrating the mixture by using ammonium hydroxide solution to form black precipitate, namely boehmite/Fe₃O₄Wrapping the carbon nano-wire, cleaning and drying; wherein the adding amount of the carbon nano-wire is 0.5g, and the adding amount of the nano-boehmite is 0.1 g;

taking boehmite/Fe₃O₄Mixing the wrapped carbon nanowires with PVDF-PVB powder (prepared by mixing polyvinylidene fluoride and polyvinyl butyral according to the mass ratio of 3: 7), then putting the mixture into a solvent to prepare a membrane casting solution, stirring the solution for 24 hours, and preparing a 4cm multiplied by 4mm size blended membrane, wherein the polyaniline wraps boehmite/Fe₃O₄The mass concentration in the casting solution is 0.5 percent, and PVDF-PVB powderThe mass concentration in the casting solution is 18 percent;

(4) respectively immersing the blend membranes prepared in the steps (1), (2) and (3) into deionized water for 48 hours, and replacing the deionized water every 12 hours;

(5) dissolving tris (hydroxymethyl) aminomethane and hydrochloric acid into an ethanol aqueous solution, oxidizing for 15min to obtain 1.0g/L of a Tric-HCl solution, adjusting the pH value of the solution to 8.5, dissolving dopamine and levodopa into the Tric-HCl solution to obtain a solution with the concentration of 2.0g/L, respectively putting the soaked blend membrane obtained in the steps (1), (2) and (3) into the dopamine and levodopa solution, soaking for 15h at 25 ℃, continuously stirring during soaking, taking out the blend membrane, and washing with deionized water for 2 times, wherein the ethanol aqueous solution is prepared by mixing water and ethanol according to the volume ratio of 8:2, the mass ratio of the tris (hydroxymethyl) aminomethane to the hydrochloric acid is 1:1, and the mass ratio of the dopamine to the levodopa is 3: 7;

(6) putting the blend membrane washed in the step (5) into FeSO of 0.1mol/L₄Soaking the solution (with pH value of 3) for 12h, and washing with deionized water for 3 times;

(7) soaking the blend membrane washed in the step (6) in 0.2mol/L sodium borohydride solution for 60min, taking out, and washing with deionized water and absolute ethyl alcohol for 3 times in sequence to respectively prepare the boehmite-doped PVDF/PVB blend membrane loaded nano zero-valent iron composite material and the polyaniline-coated boehmite/Fe₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The carbon nanowire-coated PVDF/PVB blended film-doped nano zero-valent iron-loaded composite material.

(8) Scanning Electron Microscope (SEM) representation is carried out on the nano zero-valent iron-based composite material in the embodiment, the background part in the figure is a porous PVDF/PVB blended membrane carrier, compared with an original membrane (figure 1 a) not doped with boehmite, the surface of the boehmite-doped PVDF/PVB blended membrane (figure 1 b) is rougher, small granular substances on the surface of the membrane and in the pores of the membrane are boehmite, and the size of the boehmite is nano-scale as can be seen from a ruler, which indicates that the nano-boehmite is successfully synthesized and doped into the PVDF/PVB blended membrane; in the diagram of the iron-loaded PVDF/PVB blended film, it can be seen that nanoscale zero-valent iron is uniformly distributed on the surface of the film (figure 1 c), the size of the nanoscale zero-valent iron is controlled due to the introduction of-OH functional groups, the agglomeration of the nanoscale zero-valent iron is avoided, and a foundation is provided for the recycling of the boehmite-doped PVDF/PVB blended film nano-zero-valent iron-loaded composite material.

(9) At room temperature, carrying the boehmite doped PVDF/PVB blended film on the nano zero-valent iron composite material and wrapping boehmite/Fe by polyaniline₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄Wrapping the carbon nanowire doped PVDF/PVB blended film loaded nano zero-valent iron composite material, respectively putting the wrapped carbon nanowire doped PVDF/PVB blended film loaded nano zero-valent iron composite material into 100mL of Cr (VI) solution, wherein the initial concentration of Cr (VI) is 20mg/L, the initial pH value of the reaction solution is 5, measuring the concentration of Cr (VI) after the reaction is finished for 90min, and calculating the removal rate; the removal rates were 90.24%, 96.15%, and 93.26%, respectively. As can be seen by comparison (see figure 2), the removal rate of the boehmite-doped PVDF/PVB blended film loaded nano zero-valent iron composite material to Cr (VI) is improved by 22.51% compared with that of the common unmodified nano zero-valent iron particles, and the boehmite/Fe is wrapped by the polyaniline₃O₄The removal rate of the doped PVDF/PVB blended film loaded nano zero-valent iron composite material to Cr (VI) is improved by 28.42 percent compared with the common unmodified nano zero-valent iron particles, and boehmite/Fe₃O₄Compared with the common unmodified nano zero-valent iron particles, the removal rate of the carbon nanowire-coated PVDF/PVB blended film-loaded nano zero-valent iron composite material to Cr (VI) is improved by 25.53%.

(10) Coating the polyaniline reacted with the pollutants with boehmite/Fe₃O₄Washing the PVDF/PVB doped blended film loaded nano zero-valent iron composite material with deionized water for 3 times, regenerating according to the method in the step (7), and wrapping boehmite/Fe with the regenerated polyaniline₃O₄And (3) carrying out a removal experiment on the doped PVDF/PVB blended film loaded nano zero-valent iron composite material according to the method in the step (9). Calculating to obtain the polyaniline-coated boehmite/Fe after the 2 nd activation₃O₄The removal rate of the doped PVDF/PVB blended film loaded nano zero-valent iron composite material to Cr (VI) is 95.31%, even if the removal rate of the doped PVDF/PVB blended film loaded nano zero-valent iron composite material to Cr (VI) after 6 th activation can still reach 91.32%.

Example 2: nano zero-valent iron composite material loaded on boehmite-doped PAN/PVB (Polyacrylonitrile/polyvinyl butyral) blend film and polyaniline-coated boehmite/Fe₃O₄Doped PAN/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The preparation method of the carbon nanowire-coated PAN/PVB blended film-doped nano zero-valent iron-loaded composite material and the method for removing orange II in water comprise the following specific contents:

1. the preparation of common unmodified nano zero-valent iron particles and the removal effect of the particles on orange II in water are as follows:

(2) at room temperature, 0.05g of ordinary unmodified nano zero-valent iron particles are put into 100mL of orange II solution, the initial concentration of the orange II is 80mg/L, the initial pH value of the reaction solution is 6, the concentration of the orange II is measured after 60min of reaction is finished, and the removal rate is calculated. The removal rate was 71.28%.

2. Nano zero-valent iron composite material loaded on boehmite-doped PAN/PVB (Polyacrylonitrile/polyvinyl butyral) blend film and polyaniline-coated boehmite/Fe₃O₄Doped PAN/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The preparation of the carbon nanowire-coated PAN/PVB blended film-doped nano zero-valent iron-loaded composite material and the removal effect of the composite material on orange II in water are as follows:

(1) titrating 1mol/L NaOH solution to 0.5mol/L Al (NO) at a constant speed at the temperature of 20 ℃ according to the volume ratio of 1:2₃)₃In the solution, the solution is continuously stirred in the titration process to be uniformly mixed and generateCarrying out reaction, carrying out ultrasonic treatment on the milky white mixture obtained after the reaction at 20 ℃ for 3h, taking out, then placing the mixture at 200 ℃ for vacuum drying, taking out and grinding the mixture into powder to obtain the nano boehmite;

mixing nano boehmite and PAN-PVB powder (prepared by mixing polyacrylonitrile and polyvinyl butyral according to the mass ratio of 6: 4), then putting the mixture into a DMAc solvent to prepare a membrane casting solution, stirring the solution for 30 hours, and preparing a 4cm multiplied by 4mm size blended membrane, wherein the mass concentration of the nano boehmite in the membrane casting solution is 2%, and the mass concentration of the PAN-PVB powder in the membrane casting solution is 20%;

(2) FeSO (ferric oxide) is added₄、FeCl₃And FeCl₂Dissolving the mixture in deionized water according to the mol ratio of 2:4:1 to prepare 3mol/L ferric salt solution, adjusting the pH value of the ferric salt solution to 9, and titrating the ferric salt solution by using ammonium hydroxide solution to form black precipitate which is Fe₃O₄Particles of Fe₃O₄Washing the particles with ethanol and deionized water respectively, drying, and mixing with nanometer boehmite and Fe₃O₄Putting the particles and aniline into hydrochloric acid solution containing aniline according to the mass ratio of 2:2:4, performing ultrasonic treatment for 20min, adding ammonium sulfate solution, and reacting for 60min to obtain polyaniline-coated boehmite/Fe₃O₄Washing and drying, wherein the aniline-containing hydrochloric acid solution is prepared by mixing aniline and 0.1mol/L hydrochloric acid solution according to the volume ratio of 3:45, and the molar ratio of ammonium sulfate to aniline is 2: 1;

coating boehmite/Fe with polyaniline₃O₄Mixing with PAN-PVB powder (prepared by mixing polyacrylonitrile and polyvinyl butyral according to the mass ratio of 6: 4), adding into DMAc solvent to prepare membrane casting solution, stirring the solution for 30h, and preparing into a 4cm × 4cm × 4mm size blended membrane, wherein boehmite/Fe is wrapped by polyaniline₃O₄The mass concentration of the PAN-PVB powder in the membrane casting solution is 2 percent, and the mass concentration of the PAN-PVB powder in the membrane casting solution is 20 percent;

(3) FeSO (ferric oxide) is added₄、FeCl₃And FeCl₂Dissolving the carbon nano wire into deionized water according to the mol ratio of 2:4:1 to prepare ferric salt solution with the ferric ion concentration of 0.8mol/L, adjusting the pH value of the ferric salt solution to 9, putting the carbon nano wire into the deionized water for ultrasonic treatment, taking out the carbon nano wire and the nano wireAdding the rice boehmite into 18mL of iron salt solution, titrating by using ammonium hydroxide solution to form black precipitate, namely boehmite/Fe₃O₄Wrapping the carbon nano-wire, cleaning and drying; wherein the adding amount of the carbon nano-wire is 1g, and the adding amount of the nano-boehmite is 0.2 g;

taking boehmite/Fe₃O₄Mixing the wrapped carbon nanowires with PAN-PVB powder (prepared by mixing polyacrylonitrile and polyvinyl butyral according to the mass ratio of 6: 4), then putting the mixture into a DMAc solvent to prepare a membrane casting solution, stirring the solution for 30 hours, and preparing a 4cm multiplied by 4mm size blended membrane, wherein boehmite/Fe₃O₄The mass concentration of the wrapped carbon nano-wires in the membrane casting solution is 2%, and the mass concentration of the PAN-PVB powder in the membrane casting solution is 20%;

(5) dissolving tris (hydroxymethyl) aminomethane and hydrochloric acid into an ethanol aqueous solution, oxidizing for 15min to obtain 1.5g/L of a Tric-HCl solution, adjusting the pH value of the solution to 9, dissolving dopamine and levodopa into the Tric-HCl solution to obtain a solution with the concentration of 3.0g/L, respectively putting the soaked blend membrane obtained in the steps (1), (2) and (3) into the dopamine and levodopa solution, soaking for 18h at 30 ℃, continuously stirring during soaking, taking out the blend membrane, and washing with deionized water for 3 times, wherein the ethanol aqueous solution is prepared by mixing water and ethanol according to the volume ratio of 7:3, the mass ratio of the tris (hydroxymethyl) aminomethane to the hydrochloric acid is 2:1, and the mass ratio of the dopamine to the levodopa is 6: 4;

(6) putting the blend membrane washed in the step (5) into FeSO of 0.5mol/L₄Soaking the solution (with pH value of 4) for 12h, and washing with deionized water for 2 times;

(7) soaking the blend membrane washed in the step (6) in 2mol/L sodium borohydride solution for 40min, taking out, and sequentially washing with deionized water and absolute ethyl alcohol for 2 times to respectively prepare the boehmite-doped PAN/PVB blend membrane loaded nano zero-valent iron composite material and the polyaniline-coated boehmite/Fe₃O₄Doped PAN/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The carbon nanowire-coated PAN/PVB blended film-doped nano zero-valent iron-loaded composite material.

(8) At room temperature, carrying the boehmite doped PAN/PVB blended film with the nano zero-valent iron composite material and wrapping boehmite/Fe with polyaniline₃O₄Doped PAN/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The carbon nanowire-coated PAN/PVB blended film-doped nano zero-valent iron-loaded composite material is respectively placed into 100mL of orange II solution, the initial concentration of the orange II is 80mg/L, the initial pH value of the reaction solution is 6, the concentration of the orange II is measured after the reaction is finished for 60min, and the removal rate is calculated. The removal rates were 91.59%, 97.33%, and 95.41%, respectively. As can be seen by comparison (see figure 3), the removal rate of the boehmite-doped PAN/PVB blend membrane-supported nano zero-valent iron composite material to orange II is improved by 20.31 percent compared with that of the common unmodified nano zero-valent iron particles, and the boehmite/Fe is wrapped by the polyaniline₃O₄Compared with the common unmodified nano zero-valent iron particles, the removal rate of the doped PAN/PVB blended film loaded nano zero-valent iron composite material to orange II is improved by 26.05 percent, and boehmite/Fe₃O₄The removal rate of the carbon nanowire-coated PAN/PVB blended film-loaded nano zero-valent iron-loaded composite material to orange II is improved by 24.13 percent compared with that of the common unmodified nano zero-valent iron particles.

(9) Coating the polyaniline reacted with the pollutants with boehmite/Fe₃O₄Washing the PAN/PVB doped blend film loaded nano zero-valent iron composite material with deionized water for 3 times, regenerating according to the step (7), and wrapping boehmite/Fe with the regenerated polyaniline₃O₄And (4) carrying out a removal experiment on the doped PAN/PVB blended film loaded nano zero-valent iron composite material according to the method in the step (8). Calculating to obtain the polyaniline-coated boehmite/Fe after the 2 nd activation₃O₄The removal rate of the doped PAN/PVB blended film loaded nano zero-valent iron composite material to the orange II is 96.82%, and the removal rate of the doped PAN/PVB blended film loaded nano zero-valent iron composite material to the orange II can still reach 93.46% even after the 6 th activation.

Example 3: nano zero-valent iron composite material loaded on boehmite-doped PVDF/PVB (polyvinylidene fluoride/polyvinyl butyral) blend film and polyaniline-coated boehmite/Fe₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The preparation method of the carbon nanowire-coated PVDF/PVB blended film-doped nano zero-valent iron-loaded composite material and the removal of methyl orange in water comprise the following specific contents:

1. the preparation of common unmodified nano zero-valent iron particles and the removal effect of the common unmodified nano zero-valent iron particles on methyl orange in water are as follows:

(2) at room temperature, 0.05g of ordinary unmodified nano zero-valent iron particles are put into 100mL of methyl orange solution, the initial concentration of methyl orange is 40mg/L, the initial pH value of the reaction solution is 6, the concentration of methyl orange is measured after 60min of reaction is finished, and the removal rate is calculated. The removal rate was 74.73%.

2. Nano zero-valent iron composite material carried by boehmite-doped PVDF/PVB blended film and polyaniline-coated boehmite/Fe₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The preparation of the carbon nanowire-coated PVDF/PVB blended film-doped nano zero-valent iron-loaded composite material and the removal effect of the composite material on methyl orange in water are as follows:

(1) titrating 2.8mol/L NaOH solution to 1mol/L Al (NO) at a constant speed at 30 ℃ according to the volume ratio of 1:1.5₃)₃Stirring continuously in the titration process to mix uniformly and react, performing ultrasonic treatment at 22 deg.C for 3 hr to obtain milky white mixture, taking out, vacuum drying at 210 deg.C, taking out, grinding into powderThe powder is the nano boehmite;

mixing nano boehmite with PVDF-PVB powder (prepared by mixing polyvinylidene fluoride and polyvinyl butyral according to the mass ratio of 7: 3), then putting the mixture into a DMAc solvent to prepare a membrane casting solution, stirring the solution for 40 hours, and preparing a 4cm multiplied by 4mm size blended membrane, wherein the mass concentration of the nano boehmite in the membrane casting solution is 4%, and the mass concentration of the PVDF-PVB powder in the membrane casting solution is 25%;

(2) FeSO (ferric oxide) is added₄、FeCl₃And FeCl₂Dissolving the mixture in deionized water according to the mol ratio of 1.5:5:2 to prepare 4mol/L ferric salt solution, adjusting the pH value of the ferric salt solution to be 11, and titrating the solution by using ammonium hydroxide solution to form black precipitate which is Fe₃O₄Particles of Fe₃O₄Washing the particles with ethanol and deionized water respectively, drying, and mixing with nanometer boehmite and Fe₃O₄Putting the particles and aniline in a mass ratio of 1.5:2:3 into hydrochloric acid solution containing aniline, performing ultrasonic treatment for 18min, adding ammonium sulfate solution, and reacting for 80min to obtain polyaniline-coated boehmite/Fe₃O₄Washing and drying, wherein the aniline-containing hydrochloric acid solution is prepared by mixing aniline and 0.1mol/L hydrochloric acid solution according to the volume ratio of 3:40, and the molar ratio of ammonium sulfate to aniline is 1.5: 1;

coating boehmite/Fe with polyaniline₃O₄Mixing with PVDF-PVB powder (prepared by mixing polyvinylidene fluoride and polyvinyl butyral according to the mass ratio of 7: 3), then putting into DMAc solvent to prepare membrane casting solution, stirring the solution for 40h, and preparing into a 4cm multiplied by 4mm size blended membrane, wherein the boehmite/Fe is wrapped by polyaniline₃O₄The mass concentration of the PVDF-PVB powder in the membrane casting solution is 4 percent, and the mass concentration of the PVDF-PVB powder in the membrane casting solution is 25 percent;

(3) FeSO (ferric oxide) is added₄、FeCl₃And FeCl₂Dissolving the carbon nano wires in deionized water according to a molar ratio of 1.5:5:1.5 to prepare an iron salt solution with iron ion concentration of 1mol/L, adjusting the pH value of the iron salt solution to 11, putting the carbon nano wires into the deionized water for ultrasonic treatment, taking out the carbon nano wires and the nano boehmite, adding the carbon nano wires and the nano boehmite into 20mL of the iron salt solution, titrating the solution with ammonium hydroxide solution to form black precipitate, namely boehmite ionFe₃O₄Wrapping the carbon nano-wire, cleaning and drying; wherein the adding amount of the carbon nano-wire is 2g, and the adding amount of the nano-boehmite is 0.3 g;

taking boehmite/Fe₃O₄Mixing the wrapped carbon nano-wires with PVDF-PVB powder (prepared by mixing polyvinylidene fluoride and polyvinyl butyral according to the mass ratio of 7: 3), then putting the mixture into a DMAc solvent to prepare a membrane casting solution, stirring the solution for 40 hours, and preparing a 4cm multiplied by 4mm size blended membrane, wherein boehmite/Fe₃O₄The mass concentration of the wrapped carbon nano-wires in the membrane casting solution is 4%, and the mass concentration of PVDF-PVB powder in the membrane casting solution is 25%;

(5) dissolving tris (hydroxymethyl) aminomethane and hydrochloric acid into an ethanol aqueous solution, oxidizing for 15min to prepare a 2g/L Tric-HCl solution, adjusting the pH value of the solution to 10, dissolving dopamine and levodopa into the Tric-HCl solution to prepare a solution with the concentration of 2.5g/L, respectively putting the soaked blend membrane obtained in the steps (1), (2) and (3) into the dopamine and levodopa solution, soaking for 15h at 35 ℃, stirring continuously during soaking, taking out the blend membrane, and washing with deionized water for 3 times, wherein the ethanol aqueous solution is prepared by mixing water and ethanol according to the volume ratio of 3:1, the mass ratio of the tris (hydroxymethyl) aminomethane to the hydrochloric acid is 3:1, and the mass ratio of the dopamine to the levodopa is 7: 3;

(6) putting the blend membrane washed in the step (5) into 1mol/L FeSO₄Soaking in solution (pH 5) for 20 hr, and washing with deionized water for 3 times;

(7) soaking the blended membrane washed in the step (6) in 4mol/L potassium borohydride solution for 50min, taking out, and washing with deionized water and absolute ethyl alcohol for 3 times in sequence to respectively prepare the boehmite-doped PVDF/PVB blended membrane loaded nano zero-valent iron composite material and the polyaniline-coated boehmite/Fe₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄Coated carbonThe nano-wire is doped with PVDF/PVB blended film and carries the nano zero-valent iron composite material.

(8) At room temperature, carrying the boehmite doped PVDF/PVB blended film on the nano zero-valent iron composite material and wrapping boehmite/Fe by polyaniline₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The carbon nanowire-coated PVDF/PVB blended membrane-doped nano zero-valent iron-loaded composite material is respectively placed into 100mL of methyl orange solution, the initial concentration of methyl orange is 40mg/L, the initial pH value of the reaction solution is 6, the concentration of methyl orange is measured after 60min of reaction is finished, and the removal rate is calculated. The removal rates were 93.57%, 98.41%, and 94.51%, respectively. The comparison shows that the removal rate of the boehmite-doped PVDF/PVB blended film-loaded nano zero-valent iron composite material to methyl orange is improved by 18.84% compared with that of the common unmodified nano zero-valent iron particles, and the boehmite/Fe is wrapped by polyaniline₃O₄Compared with the common unmodified nano zero-valent iron particles, the removal rate of the PVDF/PVB blended film loaded nano zero-valent iron-doped composite material to methyl orange is improved by 23.68%, and boehmite/Fe₃O₄The removal rate of the carbon nanowire-coated PVDF/PVB blended film loaded nano zero-valent iron-loaded composite material to methyl orange is improved by 19.78 percent compared with that of common unmodified nano zero-valent iron particles.

(9) Coating the polyaniline reacted with the pollutants with boehmite/Fe₃O₄Washing the PVDF/PVB doped blended film loaded nano zero-valent iron composite material with deionized water for 3 times, regenerating according to the method in the step (7), and wrapping boehmite/Fe with the regenerated polyaniline₃O₄And (3) carrying out a removal experiment on the doped PVDF/PVB blended film loaded nano zero-valent iron composite material according to the method in the step (8). Calculating to obtain the polyaniline-coated boehmite/Fe after the 2 nd activation₃O₄The removal rate of the PVDF/PVB blended film loaded nano zero-valent iron composite material to methyl orange is 95.12%, and even after 6 th activation, the removal rate to the methyl orange can still reach 92.87%.

Example 4: nano zero-valent iron composite material loaded on boehmite-doped PAN/PVB (Polyacrylonitrile/polyvinyl butyral) blend film and polyaniline-coated boehmite/Fe₃O₄Doped PAN/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The preparation method of the carbon nanowire-coated PAN/PVB blended film-doped nano zero-valent iron-loaded composite material and the removal of metronidazole in water comprise the following specific contents:

1. the preparation of common unmodified nano zero-valent iron particles and the removal effect of the particles on metronidazole in water are as follows:

(2) at room temperature, 0.05g of ordinary unmodified nano zero-valent iron particles are put into 100mL of metronidazole solution, the initial concentration of metronidazole is 20mg/L, the initial pH value of the reaction solution is 5, the concentration of metronidazole is measured after 90min of reaction is finished, and the removal rate is calculated. The removal rate was 50.31%.

2. Nano zero-valent iron composite material loaded on boehmite-doped PAN/PVB (Polyacrylonitrile/polyvinyl butyral) blend film and polyaniline-coated boehmite/Fe₃O₄Doped PAN/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The preparation of the carbon nanowire-coated PAN/PVB blended film-doped nanoscale zero-valent iron-loaded composite material and the removal effect of the composite material on metronidazole in water are as follows:

(1) titrating 2.5mol/L NaOH solution to 0.5mol/L Al (NO) at constant speed at 35 ℃ according to the volume ratio of 1:1₃)₃In the solution, continuously stirring in the titration process to uniformly mix and react, carrying out ultrasonic treatment on a milky mixture obtained after the reaction at 25 ℃ for 3 hours, taking out, then placing at 200 ℃ for vacuum drying, taking out and grinding into powder to obtain the nano boehmite;

mixing nano boehmite and PAN-PVB powder (prepared by mixing polyacrylonitrile and polyvinyl butyral according to the mass ratio of 3: 7), then putting the mixture into a DMAc solvent to prepare a membrane casting solution, stirring the solution for 30 hours, and preparing a 4 cm-4 mm size blend membrane, wherein the mass concentration of the nano boehmite in the membrane casting solution is 1.5%, and the mass concentration of the PAN-PVB powder in the membrane casting solution is 20%;

(2) FeSO (ferric oxide) is added₄、FeCl₃And FeCl₂Dissolving the mixture in deionized water according to the mol ratio of 1:5:2 to prepare 2.5mol/L ferric salt solution, adjusting the pH value of the ferric salt solution to 9, and titrating the solution by using ammonium hydroxide solution to form black precipitate which is Fe₃O₄Particles of Fe₃O₄Washing the particles with ethanol and deionized water respectively, drying, and mixing with nanometer boehmite and Fe₃O₄Putting the particles and aniline into hydrochloric acid solution containing aniline according to the mass ratio of 1.5:2:2.5, performing ultrasonic treatment for 20min, adding ammonium sulfate solution, and reacting for 100min to obtain the polyaniline-coated boehmite/Fe₃O₄Washing and drying, wherein the aniline-containing hydrochloric acid solution is prepared by mixing aniline and 0.1mol/L hydrochloric acid solution according to the volume ratio of 3:50, and the molar ratio of ammonium sulfate to aniline is 1.5: 1;

coating boehmite/Fe with polyaniline₃O₄Mixing with PAN-PVB powder (prepared by mixing polyacrylonitrile and polyvinyl butyral according to the mass ratio of 3: 7), then placing into DMAc solvent to prepare membrane casting solution, stirring the solution for 30h, and preparing into a 4cm × 4cm × 4mm size blended membrane, wherein boehmite/Fe is wrapped by polyaniline₃O₄The mass concentration of the PAN-PVB powder in the membrane casting solution is 1.5 percent, and the mass concentration of the PAN-PVB powder in the membrane casting solution is 20 percent;

(3) FeSO (ferric oxide) is added₄、FeCl₃And FeCl₂Dissolving the carbon nano wires in deionized water according to the mol ratio of 1.5:3:2 to prepare ferric salt solution with the ferric ion concentration of 1mol/L, adjusting the pH value of the ferric salt solution to 9, putting the carbon nano wires into the deionized water for ultrasonic treatment, taking out the carbon nano wires and the nano boehmite, adding the carbon nano wires and the nano boehmite into 20mL of the ferric salt solution, titrating the mixture by using ammonium hydroxide solution to form black precipitate, namely boehmite/Fe₃O₄Wrapping the carbon nano-wire, cleaning and drying; wherein the adding amount of the carbon nano wire is 1.5gThe adding amount of the nano boehmite is 0.1 g;

taking boehmite/Fe₃O₄Mixing the wrapped carbon nanowires with PAN-PVB powder (prepared by mixing polyacrylonitrile and polyvinyl butyral according to the mass ratio of 3: 7), then putting the mixture into a DMAc solvent to prepare a membrane casting solution, stirring the solution for 30 hours, and preparing a 4cm multiplied by 4mm size blended membrane, wherein boehmite/Fe₃O₄The mass concentration of the wrapped carbon nano-wires in the membrane casting solution is 1.5 percent, and the mass concentration of the PAN-PVB powder in the membrane casting solution is 20 percent;

(5) dissolving tris (hydroxymethyl) aminomethane and hydrochloric acid into an ethanol aqueous solution, oxidizing for 15min to obtain 1.5g/L of a Tric-HCl solution, adjusting the pH value of the solution to 10, dissolving dopamine and levodopa into the Tric-HCl solution to obtain a solution with the concentration of 2.0g/L, respectively putting the soaked blend membrane obtained in the steps (1), (2) and (3) into the dopamine and levodopa solution, soaking for 15h at 35 ℃, stirring continuously during soaking, taking out the blend membrane, and washing with deionized water for 3 times, wherein the ethanol aqueous solution is prepared by mixing water and ethanol according to the volume ratio of 1:1, the mass ratio of the tris (hydroxymethyl) aminomethane to the hydrochloric acid is 1.5:1, and the mass ratio of the dopamine to the levodopa is 3: 7;

(6) putting the blend membrane washed in the step (5) into 1mol/L FeSO₄Soaking the solution (with pH value of 3) for 12h, and washing with deionized water for 2 times;

(7) soaking the blend membrane washed in the step (6) in 3mol/L sodium borohydride solution for 40min, taking out, and sequentially washing with deionized water and absolute ethyl alcohol for 2 times to respectively prepare the boehmite-doped PAN/PVB blend membrane loaded nano zero-valent iron composite material and the polyaniline-coated boehmite/Fe₃O₄Doped PAN/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The carbon nanowire-coated PAN/PVB blended film-doped nano zero-valent iron-loaded composite material.

(8) At room temperature, carrying the boehmite doped PAN/PVB blended film with the nano zero-valent iron composite material and wrapping boehmite/Fe with polyaniline₃O₄Doped PAN/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The carbon nanowire-wrapped mixed PAN/PVB blended film loaded nano zero-valent iron composite material is respectively placed into 100mL of metronidazole solution, the initial concentration of metronidazole is 20mg/L, the initial pH value of the reaction solution is 5, the concentration of metronidazole is measured after 90min of reaction is finished, and the removal rate is calculated. The removal rates were 70.84%, 78.49%, and 73.52%, respectively. The comparison shows that the removal rate of the boehmite-doped PAN/PVB blend membrane-loaded nano zero-valent iron composite material on metronidazole is improved by 20.53 percent compared with that of the common unmodified nano zero-valent iron particles, and the boehmite/Fe is coated by polyaniline₃O₄Compared with the common unmodified nano zero-valent iron particles, the removal rate of the doped PAN/PVB blended film loaded nano zero-valent iron composite material to metronidazole is improved by 28.18%, and boehmite/Fe₃O₄The removal rate of metronidazole from the carbon nanowire-coated PAN/PVB blended film-loaded nano zero-valent iron composite material is increased by 23.21% compared with that of the ordinary unmodified nano zero-valent iron particles.

(9) Coating the polyaniline reacted with the pollutants with boehmite/Fe₃O₄Washing the PAN/PVB doped blend film loaded nano zero-valent iron composite material with deionized water for 3 times, regenerating according to the step (7), and wrapping boehmite/Fe with the regenerated polyaniline₃O₄And (4) carrying out a removal experiment on the doped PAN/PVB blended film loaded nano zero-valent iron composite material according to the method in the step (8). Calculating to obtain the polyaniline-coated boehmite/Fe after the 2 nd activation₃O₄The removal rate of the composite material doped with PAN/PVB blended film and loaded with nano zero-valent iron to metronidazole is 76.42%, and even after the 6 th activation, the removal rate to metronidazole can still reach 71.91%.

Example 5: nano zero-valent iron composite material carried by boehmite-doped PVDF/PVB blended film and polyaniline-coated boehmite/Fe₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄Preparation method of carbon nanowire-coated PVDF/PVB (polyvinylidene fluoride/polyvinyl butyral) blended film loaded nano zero-valent iron composite material and preparation method thereofThe method for removing tetracycline in water comprises the following specific steps:

the preparation of common unmodified nano zero-valent iron particles and the removal effect of the particles on tetracycline in water are as follows:

(2) at room temperature, putting 0.05g of ordinary unmodified nano zero-valent iron particles into 100mL of tetracycline solution, wherein the initial concentration of tetracycline is 40mg/L, the initial pH value of the reaction solution is 6, measuring the concentration of tetracycline after the reaction is finished for 60min, and calculating the removal rate. The removal rate was 61.97%.

Nano zero-valent iron composite material carried by boehmite-doped PVDF/PVB blended film and polyaniline-coated boehmite/Fe₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄Preparation of a carbon nanowire-wrapped doped PVDF/PVB blend film loaded nano zero-valent iron composite material (method refer to example 1) and its effect of removing tetracycline in water:

carrying nano zero-valent iron composite material on boehmite-doped PVDF/PVB blended film and polyaniline-coated boehmite/Fe₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The carbon nanowire-coated PVDF/PVB blended membrane loaded nano zero-valent iron-loaded composite material is respectively placed into 100mL of tetracycline solution, the initial concentration of tetracycline is 40mg/L, the initial pH value of the reaction solution is 6, the concentration of tetracycline is measured after the reaction is finished for 60min, and the removal rate is calculated. The removal rates were 72.21%, 79.35%, and 74.8%, respectively6 percent. The comparison shows that the removal rate of the boehmite-doped PVDF/PVB blended film-loaded nano zero-valent iron composite material to tetracycline is improved by 10.24 percent compared with that of the common unmodified nano zero-valent iron particles, and the boehmite/Fe is wrapped by the polyaniline₃O₄Compared with the common unmodified nano zero-valent iron particles, the removal rate of the doped PVDF/PVB blended film loaded nano zero-valent iron composite material to tetracycline is improved by 17.38%, and boehmite/Fe₃O₄The removal rate of the carbon nanowire-coated PVDF/PVB blended film loaded nano zero-valent iron-loaded composite material on tetracycline is improved by 12.89% compared with that of the common unmodified nano zero-valent iron particles.

Coating the polyaniline reacted with the pollutants with boehmite/Fe₃O₄Washing the PVDF/PVB doped blended film loaded nano zero-valent iron composite material with deionized water for 3 times, regenerating according to the method in the step (7), and wrapping boehmite/Fe with the regenerated polyaniline₃O₄The doped PVDF/PVB blended film loaded nano zero-valent iron composite material is subjected to tetracycline removal experiment according to the method. Calculating to obtain the polyaniline-coated boehmite/Fe after the 2 nd activation₃O₄The removal rate of the doped PVDF/PVB blended film loaded nano zero-valent iron composite material to tetracycline is 77.36%, even the removal rate to tetracycline after 6 th activation can still reach 71.49%.

Example 6: nano zero-valent iron composite material carried by boehmite-doped PVDF/PVB blended film and polyaniline-coated boehmite/Fe₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The preparation method of the carbon nanowire-coated PVDF/PVB blended film-doped nano zero-valent iron-loaded composite material and the removal of hexachlorobenzene in water comprise the following specific contents:

the preparation of common unmodified nano zero-valent iron particles and the removal effect of the particles on hexachlorobenzene in water are as follows:

(1) measuring 100mL KBH with concentration of 1mol/L under the nitrogen protection environment₄The solution is added dropwise with 100mL FeSO with the concentration of 1mol/L₄In the solution, continuously stirring uniformly by a magnetic stirrer in the process until the reaction is finished, passing the reacted solution through a Buchner funnel with a 0.22 micron microporous filter membrane, and washing with deionized water 3Performing suction filtration to dryness, immersing the obtained solid particles into 50mL of absolute ethyl alcohol, stirring and soaking for 5min, filtering the solution by using a sand core filtering device, sequentially washing for 2 times by using the absolute ethyl alcohol and acetone, draining, putting the nano zero-valent iron particles into a dryer for 5 days, grinding, and sealing and storing to obtain common unmodified nano zero-valent iron particles;

(2) at room temperature, 0.04g of ordinary unmodified nano zero-valent iron particles are put into 100mL of hexachlorobenzene solution, the initial concentration of hexachlorobenzene is 100mg/L, the initial pH value of the reaction solution is 5.8, the concentration of hexachlorobenzene is measured after 90min of reaction is finished, and the removal rate is calculated. The removal rate was 41.23%.

Nano zero-valent iron composite material carried by boehmite-doped PVDF/PVB blended film and polyaniline-coated boehmite/Fe₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄Preparation of a carbon nanowire-wrapped doped PVDF/PVB blend film loaded nano zero-valent iron composite material (method refer to example 3) and its effect of removing hexachlorobenzene in water:

at room temperature, carrying the boehmite doped PVDF/PVB blended film on the nano zero-valent iron composite material and wrapping boehmite/Fe by polyaniline₃O₄Doped PVDF/PVB blended film loaded nano zero-valent iron composite material and boehmite/Fe₃O₄The carbon nanowire-coated PVDF/PVB blended membrane-doped nano zero-valent iron-loaded composite material is respectively placed into 100mL of hexachlorobenzene solution, the initial concentration of hexachlorobenzene is 100mg/L, the initial pH value of the reaction solution is 5.8, the concentration of hexachlorobenzene is measured after 90min reaction is finished, and the removal rate is calculated. The removal rates were 57.24%, 64.75%, and 59.12%, respectively. The comparison shows that the removal rate of the boehmite-doped PVDF/PVB blended film loaded nano zero-valent iron composite material to hexachlorobenzene is improved by 16.01 percent compared with that of the common unmodified nano zero-valent iron particles, and the boehmite/Fe is wrapped by polyaniline₃O₄Compared with the common unmodified nano zero-valent iron particles, the removal rate of the doped PVDF/PVB blended film loaded nano zero-valent iron composite material to hexachlorobenzene is improved by 23.52 percent, and boehmite/Fe₃O₄Removal of hexachlorobenzene by coating carbon nanowire doped PVDF/PVB blended membrane loaded nano zero-valent iron composite materialThe removal rate is improved by 17.89 percent compared with the common unmodified nano zero-valent iron particles.

Coating the polyaniline reacted with the pollutants with boehmite/Fe₃O₄Washing the PVDF/PVB doped blended film loaded nano zero-valent iron composite material with deionized water for 3 times, regenerating according to the method in the step (7), and wrapping boehmite/Fe with the regenerated polyaniline₃O₄The doped PVDF/PVB blended film loaded nano zero-valent iron composite material is subjected to a hexachlorobenzene removal experiment according to the method. Calculating to obtain the polyaniline-coated boehmite/Fe after the 2 nd activation₃O₄The removal rate of the doped PVDF/PVB blended film loaded nano zero-valent iron composite material to hexachlorobenzene is 61.18%, and even the removal rate to hexachlorobenzene after 6 th activation can still reach 58.76%.

Claims

1. A preparation method of a hydrophilic material doped blending membrane loaded nano zero-valent iron composite material is characterized by comprising the following specific steps:

after the nano-boehmite is prepared, FeSO₄、FeCl₃And FeCl₂Dissolving the iron salt solution in deionized water according to the molar ratio of (1-2) to (3-5) to (1-2) to prepare an iron salt solution, adjusting the pH value of the iron salt solution to 9-11, and titrating the iron salt solution by using an ammonium hydroxide solution to form a black precipitate which is Fe₃O₄Particles of Fe₃O₄Washing the particles with ethanol and deionized water respectively, drying, and mixing with nanometer boehmite and Fe₃O₄Putting the particles and aniline in a mass ratio of (1-2) to (2-5) into hydrochloric acid solution containing aniline, performing ultrasonic treatment for 15-20 min, adding ammonium sulfate solution, and reacting for 60-120 min to obtain polyaniline-coated boehmite/Fe₃O₄Washing and drying, wherein the hydrochloric acid solution containing aniline is in a volume ratio of 3: 40-50Mixing aniline and 0.1mol/L hydrochloric acid solution to obtain the ammonium sulfate/aniline mixed solution, wherein the molar ratio of the ammonium sulfate to the aniline is 1-2: 1; then coating the polyaniline with boehmite/Fe₃O₄Mixing with PVDF-PVB powder or PAN-PVB powder;

2. A preparation method of a hydrophilic material doped blending membrane loaded nano zero-valent iron composite material is characterized by comprising the following specific steps:

(1) according to the volume ratio of 1: 1-2, titrating NaOH solution to Al (NO) at constant speed₃)₃In the solution, continuously stirring in the titration process to uniformly mix and react, and obtaining milk white after reactionPerforming ultrasonic treatment on the mixture at the temperature of 20-25 ℃ for 3 hours, taking out the mixture, then placing the mixture at the temperature of 200-220 ℃ for vacuum drying, taking out the mixture, and grinding the mixture into powder to obtain nano boehmite;

FeSO (ferric oxide) is added₄、FeCl₃And FeCl₂Dissolving the raw materials in deionized water according to a molar ratio of (1-2) to (3-5) to (1-2) to prepare an iron salt solution with the iron ion concentration of 0.5-1 mol/L, adjusting the pH value of the iron salt solution to 9-11, putting the carbon nanowires into the deionized water for ultrasonic treatment, taking out the carbon nanowires and the nano boehmite, adding the carbon nanowires and the nano boehmite into 15-20 mL of the iron salt solution, titrating with an ammonium hydroxide solution to form a black precipitate, namely boehmite/Fe₃O₄Wrapping the carbon nano-wire, cleaning and drying; wherein the adding amount of the carbon nano-wires is 0.5-2 g, the adding amount of the nano-boehmite is 0.1-0.3 g, and then the boehmite/Fe is added₃O₄Coating the carbon nano wires and mixing with PVDF-PVB powder or PAN-PVB powder;

3. The preparation method of the hydrophilic material doped blend membrane loaded nano zero-valent iron composite material according to any one of claims 1 to 2, characterized in that: the titration in the step (1) is carried out at 5-40 ℃.

4. The preparation method of the hydrophilic material doped blend membrane loaded nano zero-valent iron composite material according to any one of claims 1 to 2, characterized in that: the concentration of the NaOH solution in the step (1) is 0.5-3 mol/L; al (NO)₃)₃The concentration of the solution is 0.1 mol/L-1 mol/L.

5. The preparation method of the hydrophilic material doped blend membrane loaded nano zero-valent iron composite material according to claim 1, characterized in that: the concentration of iron ions in the iron salt solution in the step (1) is 1-4 mol/L.

6. The preparation method of the hydrophilic material doped blend membrane loaded nano zero-valent iron composite material according to any one of claims 1 to 2, characterized in that: the solvent in the step (2) is dimethylacetamide.

7. The preparation method of the hydrophilic material doped blend membrane loaded nano zero-valent iron composite material according to any one of claims 1 to 2, characterized in that: the PVDF-PVB powder is prepared by mixing polyvinylidene fluoride and polyvinyl butyral according to the mass ratio of 3: 7-7: 3; the PAN-PVB powder is prepared by mixing polyacrylonitrile and polyvinyl butyral according to the mass ratio of 3: 7-7: 3.

8. The preparation method of the hydrophilic material doped blend membrane loaded nano zero-valent iron composite material according to any one of claims 1 to 2, characterized in that: the iron salt solution in the step (4) is 0.1mol/L ℃1mol/L FeSO₄The pH value of the solution is 3-5.

9. The preparation method of the hydrophilic material doped blend membrane loaded nano zero-valent iron composite material according to any one of claims 1 to 2, characterized in that: the solution of borohydride salt in the step (5) is sodium borohydride or potassium borohydride solution with the concentration of 0.2-4 mol/L.

10. The hydrophilic material doped blended membrane loaded nano zero-valent iron composite material prepared by the preparation method of the hydrophilic material doped blended membrane loaded nano zero-valent iron composite material according to any one of claims 1 to 9.

11. The application of the hydrophilic material doped blend membrane loaded nano zero-valent iron composite material of claim 10 in removing heavy metal ions, dyes, antibiotics and chlorinated organic matters in wastewater.