A photocatalytic material for degrading PFOA and a preparation method thereof

Abstract

The present application relates to the technical field of photocatalytic degradation materials, in particular to a photocatalytic material for degrading PFOA and a preparation method thereof. The present application uses titanium foil as a TiO2 NT template in an electrochemical reactor with a direct current power supply, uses the titanium foil as an anode and graphite as a cathode, obtains highly ordered and vertically arranged TiO2 NTs after anodic oxidation, and modifies the TiO2 NTs through MIP. The molecular imprinting technology can enable the photocatalyst to selectively identify and combine with target molecules with high affinity. The doping of metal iron ions can introduce new energy levels in the band gap of the semiconductor TiO2, thereby enhancing the visible light absorption capacity of TiO2 by adjusting the band gap. Not only can the visible light absorption capacity of TiO2 be enhanced, but also the adsorption capacity of the target pollutant PFOA can be improved, thereby promoting the efficient degradation of PFOA.

Description

Technical Field

[0001] This invention relates to the field of photocatalytic degradation materials technology, specifically to a photocatalytic material for degrading PFOA and its preparation method. Background Technology

[0002] Perfluorinated and polyfluoroalkyl substances, especially perfluorooctanoic acid (PFOA), have been widely used in numerous industrial and consumer sectors since the 1940s, including fluoropolymer surfactants, aqueous film-forming foams, metal plating, textiles, and household products. Due to the high electronegativity of fluorine and the strong stability of the CF bond (531.5 KJ / mol), PFOA exhibits extremely high persistence to environmental degradation and biological processes, and traditional treatment technologies, including oxidation and reduction processes, are ineffective in degrading PFOA. Therefore, the discharge of PFOA-containing wastewater and the release of PFOA-containing solid waste lead to increasingly higher levels of PFOA in soil, groundwater, and surface water. Increasing health research data indicate that exposure to PFOA can cause numerous health problems, such as thyroid hormone disorders, impaired immune systems, and low birth weight in infants. Therefore, there is an urgent need to develop an effective technology for the removal of PFOA.

[0003] Studies have shown that photocatalysis is a promising technology for addressing persistent organic pollutant (PFOA) pollution and energy constraints, as it can meet the requirements for PFOA removal without consuming additional energy. Under sunlight irradiation, photocatalysts are excited to generate redox-active substances such as superoxide radicals, hydroxyl radicals, and holes, which contribute to PFOA degradation. However, the low responsiveness of wide-bandgap photocatalysts to visible light and the tendency for generated electrons and holes to recombine during migration limit the efficiency of photocatalytic PFOA degradation. Furthermore, in practical applications, the low concentration and complex composition of PFOA in water bodies mean that the adsorption and catalytic degradation of PFOA by photocatalysts are affected by other pollutants. Therefore, suppressing photogenerated electron-hole recombination and improving the adsorption capacity of photocatalysts for PFOA are crucial for the efficient degradation of PFOA using photocatalytic technology. Molecular imprinting technology offers the opportunity to endow photocatalysts with good selectivity because they can be coupled with customized acceptors that can selectively recognize and bind target molecules with high affinity. Noble metal catalysts such as Au, Ag, and Pd have excellent effects in photocatalytic modification, but their high price increases their application cost.

[0004] To address the aforementioned problems and improve the photodegradation efficiency of photocatalytic degradation materials, this invention provides a photocatalytic material for degrading PFOA and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a photocatalytic material for degrading PFOA and a method for preparing the same, so as to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A method for preparing a photocatalytic material for degrading PFOA includes the following steps:

[0008] Step 1: Disperse TiO2NT in ethanol and stir until homogeneous. Then, add Fe(NO3)3·9H2O solution dropwise while stirring. Heat treat at 150-160℃ for 8-9 hours, precipitate, wash, dry, and then anneal at 300-320℃ for 1-2 hours in a nitrogen atmosphere to obtain Fe / TiO2NT.

[0009] Step 2: Add Fe / TiO2NT to NaOH solution for pretreatment for 40-60 minutes, wash and dry, then immerse the treated Fe / TiO2NT in anhydrous toluene solution containing 3-aminopropyltriethoxysilane and 3-methacryloyloxypropyltrimethoxysilane, purge with nitrogen, heat at 50-55℃ for 5-6 hours, wash and dry to obtain modified Fe / TiO2NT;

[0010] Step 3: Drop the molecularly imprinted polymer mixture onto both sides of the modified Fe / TiO2NT, then insert it into a quartz tube, seal it, and purge it with nitrogen for 25-30 minutes. Then, polymerize it under 350nm ultraviolet light for 10-11 hours, wash it, and obtain the PFOA photocatalytic degradation material.

[0011] In a more optimized manner, the preparation method of TiO2NT in step one is as follows: using titanium foil as the anode and graphite sheet as the cathode, magnetic stirring is performed at 25-30℃, and a constant voltage is applied in an electrolyte of ethylene glycol and ammonium fluoride, followed by anodic oxidation, washing, drying, and annealing to obtain TiO2NT.

[0012] In a more optimized manner, in step three, the preparation method of the molecularly imprinted polymer mixture is as follows: perfluorooctanoic acid is added to a mixed solution of methanol and acetonitrile, acrylamide, ethylene glycol dimethacrylate and azobisisobutyronitrile, and the mixture is ultrasonically mixed to obtain the molecularly imprinted polymer mixture.

[0013] Ideally, the titanium foil has a purity of 99.5% and a thickness of 0.1-0.2 mm.

[0014] Ideally, the anodizing temperature is 15-17℃ and the time is 6-7 hours; the annealing temperature is 400-420℃ and the time is 1-3 hours.

[0015] Ideally, the concentrations of perfluorooctanoic acid (PFOA) are 0.03-0.04 mol / L, acrylamide is 0.5-0.6 mol / L, ethylene glycol dimethacrylate is 1.5-1.7 mol / L, and azobisisobutyronitrile (AIBN) is 0.05-0.06 mol / L.

[0016] Ideally, the volume ratio of methanol to acetonitrile is 1:1.

[0017] In a more optimized manner, in step three, the modified Fe / TiO2NT is further modified by the following method: take the modified Fe / TiO2NT and aminostyrene photosensitizer, heat to 80-85℃, mix evenly, and dry to obtain modified Fe / TiO2NT.

[0018] A more optimized method for preparing the aminostyrene photosensitizer includes the following steps:

[0019] S1: Take 3,4-dihydroxybenzaldehyde, p-nitrobenzyl acetic acid and hexahydropyridine, mix them evenly, heat to 100-105℃ and react for 24-26 h, filter, separate and purify, recrystallize to obtain nitrated styrene photosensitizer;

[0020] S2: Add nitrated styrene photosensitizer, deionized water, and platinum-carbon catalyst to the reactor, purge with nitrogen for 5-10 min, raise the temperature to 50-55℃, heat for 20-25 min, charge with 4MPaH2, and stir the reaction for 3-3.5 h to obtain amino-modified styrene photosensitizer.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0022] (1) This invention uses titanium foil as a TiO2NT (titanium dioxide nanotube) template in an electrochemical reactor with a DC power supply, with titanium foil as the anode and graphite as the cathode. Highly ordered and vertically arranged TiO2NTs are obtained through anodic oxidation. In addition to its application in photocatalysis, TiO2NTs can also be used in adsorption and other fields. Moreover, after modification, TiO2NTs have strong selectivity and adsorption properties, enabling them to adsorb target molecules.

[0023] Iron ions are doped into TiO2NTs, a simple and stable material, using a solvothermal treatment method, and then modified with molecularly imprinted polymer (MIP). The doping of metallic iron ions introduces new energy levels into the band gap of the semiconductor TiO2, enhancing its visible light absorption capacity by adjusting the band gap. Furthermore, molecular imprinting (MIT) technology provides photocatalysts with good selectivity, allowing them to selectively recognize and bind target molecules with high affinity. This invention uses titanium foil as a template to prepare TiO2NTs, which possess high specific surface area and active sites. In addition, the co-modification of TiO2NTs with Fe and MIP not only enhances the visible light absorption capacity of TiO2 but also improves its adsorption capacity for the target pollutant PFOA, thereby promoting the efficient degradation of PFOA.

[0024] The Fe / TiO2NT composite was modified with 3-aminopropyltriethoxysilane and 3-methacryloyloxypropyltrimethoxysilane to improve its dispersibility. A molecularly imprinted polymer (MIP) was prepared using perfluorooctanoic acid as a template, acrylamide as a functional monomer, ethylene glycol dimethacrylate as a crosslinking agent, and azobisisobutyronitrile as an initiator. The use of acrylamide as a functional monomer resulted in high adsorption capacity of the photocatalytic material.

[0025] (2) In this invention, amino-modified styrene photosensitizer is used to further modify Fe / TiO2NT. Amino-modified styrene photosensitizer can generate active oxygen by absorbing light of a specific wavelength, thereby accelerating the photodegradation reaction and improving the degradation efficiency. At the same time, the amino groups on the modified Fe / TiO2NT have good compatibility with the amide groups on the molecularly imprinted polymer prepared in this invention, which further improves the degradation efficiency.

[0026] This invention provides a photocatalytic material of TiO2NT modified by metal Fe and MIP. Fe ions are doped with TiO2NT, which is simple to prepare and has stable performance, by solvothermal treatment, and TiO2NT is modified by MIP.

[0027] The TiO2NT produced by the present invention, which is co-modified with Fe metal, has better selectivity and adsorption of PFOA pollutants compared with traditional TiO2NT. At the same time, it has a low charge recombination rate and higher efficiency in photocatalytic degradation of PFOA. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] There are no special restrictions on the suppliers of the raw materials involved in this invention, and exemplary suppliers include:

[0030] Graphite sheet: A graphite sheet with a diameter of 3cm and a thickness of 0.25mm;

[0031] Titanium foil: purity 99.5%, thickness 0.1mm, diameter 3cm;

[0032] Perfluorooctane sulfonyl compounds: available from Shanghai Zhenzhun Biotechnology, catalog number: WEL-FOSAA;

[0033] Perfluorooctanoic acid (PFOA): Available from Shanghai Yuanye.

[0034] Acrylamide: Available from Sigma-Aldrich Shanghai Trading Co., Ltd., item number: V900845;

[0035] Ethylene glycol dimethacrylate: Available from Shanghai Yuanye;

[0036] 3,4-Dihydroxybenzaldehyde: can be purchased from Hubei Jiangmin Taihua Chemical Co., Ltd.;

[0037] p-Nitrophenylacetic acid: can be purchased from Shanghai Yuanye;

[0038] Hexahydropyridine: can be purchased from Hubei Hengjingrui Chemical Co., Ltd.;

[0039] Platinum-carbon catalyst: Available from Shanghai Fuli Hydrogen New Energy Technology Co., Ltd., CAS: 7440-06-4.

[0040] Example 1: A method for preparing a photocatalytic material for degrading PFOA, comprising the following steps:

[0041] Step 1: Preparation of TiO2NT:

[0042] In a cylindrical electrochemical reactor with a DC power supply, titanium foil was used as the anode and graphite sheet as the cathode. Magnetic stirring was performed at 25°C, and a constant voltage of 15V was applied to an electrolyte containing 0.09 mol / L ethylene glycol and 0.45 mol / L ammonium fluoride. After anodic oxidation at 15°C for 6 hours, the product was rinsed with deionized water, dried, and annealed at 400°C to obtain TiO2NT (titanium dioxide nanotubes).

[0043] Step 2: Preparation of Fe / TiO2NT:

[0044] 0.5 g TiO2NT was dispersed in 20 mL of ethanol and stirred until homogeneous. Then, 20 mL of Fe(NO3)3·9H2O solution was added dropwise while stirring. The resulting mixture was dissolved and heat-treated at 150 °C for 8 hours, precipitated, washed, dried at 80 °C for 12 hours, and then annealed at 300 °C for 1 hour in a nitrogen stream to obtain Fe / TiO2NT.

[0045] Step 3: Preparation of APTS and MPS modified Fe / TiO2NT:

[0046] 0.5 g of Fe / TiO2NT was added to a 0.85 mol / L NaOH solution for pretreatment for 40 minutes to hydrolyze the TiO2NT surface to form Ti-OH groups. After washing and air drying, the treated 0.5 g of Fe / TiO2NT was immersed in anhydrous toluene solution containing 0.03 v / v of 3-aminopropyltriethoxysilane and 0.03 v / v of 3-methacryloyloxypropyltrimethoxysilane. The mixture was then purged with nitrogen for 30 minutes and heated at 50 °C for 5 hours. After washing and drying, APTS and MPS modified Fe / TiO2NT were obtained.

[0047] Step 4: Preparation of PFOA photocatalytic degradation materials:

[0048] A template PFOA of 0.03 mol / L was added to a mixed solution of methanol / acetonitrile (1:1 volume ratio), 0.5 mol / L acrylamide, 1.5 mol / L ethylene glycol dimethacrylate, and 0.05 mol / L azobisisobutyronitrile (0.05 mol / L). The mixture was ultrasonically mixed for 15 minutes to obtain a molecularly imprinted polymer mixture. The molecularly imprinted polymer mixture was then dropped onto both sides of APTS and MPS-modified Fe / TiO2NT to obtain a uniform coating. The coating was then inserted into a columnar quartz tube, sealed, and purged with nitrogen for 25 minutes. Polymerization was carried out under 350 nm ultraviolet light for 10 hours. The substrate was then immersed in methanol / deionized water (1:1 volume ratio) to remove the molecular template, yielding the PFOA photocatalytic degradation material.

[0049] Example 2: A method for preparing a photocatalytic material for degrading PFOA, comprising the following steps:

[0050] Step 1: Preparation of TiO2NT:

[0051] In a cylindrical electrochemical reactor with a DC power supply, titanium foil was used as the anode and graphite sheet as the cathode. Magnetic stirring was performed at 30°C, and a constant voltage of 15V was applied to an electrolyte containing 0.09 mol / L ethylene glycol and 0.45 mol / L ammonium fluoride. After anodic oxidation at 16°C for 6.5 hours, the product was rinsed with deionized water, dried, and annealed at 410°C to obtain TiO2NT.

[0052] Step 2: Preparation of Fe / TiO2NT:

[0053] 0.5 g TiO2NT was dispersed in 20 mL of ethanol and stirred until homogeneous. Then, 20 mL of Fe(NO3)3·9H2O solution was added dropwise while stirring. The resulting mixture was heat-treated at 155 °C for 8.5 hours to dissolve, precipitate, wash, and dry at 83 °C for 13 hours. Then, it was annealed at 310 °C for 1 hour in a nitrogen atmosphere to obtain Fe / TiO2NT.

[0054] Step 3: Preparation of APTS and MPS modified Fe / TiO2NT:

[0055] 0.5 g of Fe / TiO2NT was added to a 0.85 mol / L NaOH solution for pretreatment for 50 minutes to hydrolyze the TiO2NT surface to form Ti-OH groups. After washing and air drying, the treated 0.5 g of Fe / TiO2NT was immersed in anhydrous toluene solution containing 0.03 v / v of 3-aminopropyltriethoxysilane and 0.03 v / v of 3-methacryloyloxypropyltrimethoxysilane. The mixture was then purged with nitrogen for 35 minutes and heated at 52 °C for 5.5 hours. After washing and drying, APTS and MPS modified Fe / TiO2NT were obtained.

[0056] Step 4: Preparation of PFOA photocatalytic degradation materials:

[0057] A template PFOA of 0.03 mol / L was added to a mixed solution of methanol / acetonitrile (1:1 volume ratio), 0.5 mol / L acrylamide, 1.5 mol / L ethylene glycol dimethacrylate, and 0.05 mol / L azobisisobutyronitrile (0.05 mol / L volume ratio). The mixture was ultrasonically mixed for 17 minutes to obtain a homogeneous solution. The solution was then dropped onto both sides of APTS and MPS-modified Fe / TiO2NT to obtain a uniform coating. The coating was then inserted into a columnar quartz tube, sealed, and purged with nitrogen for 25 minutes. Polymerization was carried out under 350 nm UV irradiation for 10.5 hours. The substrate was then immersed in methanol / deionized water (1:1 volume ratio) to remove the molecular template, yielding the PFOA photocatalytic degradation material.

[0058] Example 3: A method for preparing a photocatalytic material for degrading PFOA, comprising the following steps:

[0059] Step 1: Preparation of TiO2NT:

[0060] In a cylindrical electrochemical reactor with a DC power supply, titanium foil was used as the anode and graphite sheet as the cathode. Magnetic stirring was performed at 30°C, and a constant voltage of 15V was applied to an electrolyte containing 0.09 mol / L ethylene glycol and 0.45 mol / L ammonium fluoride. After anodic oxidation at 17°C for 7 hours, the product was rinsed with deionized water, dried, and annealed at 420°C to obtain TiO2NT.

[0061] Step 2: Preparation of Fe / TiO2NT:

[0062] 0.5 g TiO2NT was dispersed in 20 mL of ethanol and stirred until homogeneous. Then, 20 mL of Fe(NO3)3·9H2O solution was added dropwise while stirring. The resulting mixture was heat-treated at 160 °C for 9 hours to precipitate, washed, dried at 85 °C for 14 hours, and then annealed at 320 °C for 1.5 hours in a nitrogen atmosphere to obtain Fe / TiO2NT.

[0063] Step 3: Preparation of APTS and MPS modified Fe / TiO2NT:

[0064] 0.5 g of Fe / TiO2NT was added to a 0.85 mol / L NaOH solution for pretreatment for 60 minutes to hydrolyze the TiO2NT surface to form Ti-OH groups. After washing and air drying, the treated 0.5 g of Fe / TiO2NT was immersed in anhydrous toluene solution containing 0.03 v / v of 3-aminopropyltriethoxysilane and 0.03 v / v of 3-methacryloyloxypropyltrimethoxysilane. The mixture was then purged with nitrogen for 40 minutes and heated at 55 °C for 6 hours. After washing and drying, APTS and MPS modified Fe / TiO2NT were obtained.

[0065] Step 4: Preparation of PFOA photocatalytic degradation materials:

[0066] A template PFOA of 0.03 mol / L was added to a mixed solution of methanol / acetonitrile (1:1 volume ratio), 0.5 mol / L acrylamide, 1.5 mol / L ethylene glycol dimethacrylate, and 0.05 mol / L azobisisobutyronitrile (0.05 mol / L volume ratio). The mixture was ultrasonically mixed for 20 minutes to obtain a homogeneous solution. The solution was then dropped onto both sides of APTS and MPS-modified Fe / TiO2NT to obtain a uniform coating. The coating was then inserted into a columnar quartz tube, sealed, and purged with nitrogen for 25 minutes. Polymerization was carried out under 350 nm ultraviolet light for 11 hours. The substrate was then immersed in methanol / deionized water (1:1 volume ratio) to remove the molecular template, yielding the PFOA photocatalytic degradation material.

[0067] Example 4: A method for preparing a photocatalytic material for degrading PFOA, comprising the following steps:

[0068] Step 1: Preparation of TiO2NT:

[0069] In a cylindrical electrochemical reactor with a DC power supply, titanium foil was used as the anode and graphite sheet as the cathode. Magnetic stirring was performed at 25°C, and a constant voltage of 15V was applied to an electrolyte containing 0.09 mol / L ethylene glycol and 0.45 mol / L ammonium fluoride. After anodic oxidation at 15°C for 6 hours, the product was rinsed with deionized water, dried, and annealed at 400°C to obtain TiO2NT.

[0070] Step 2: Preparation of Fe / TiO2NT:

[0071] 0.5 g TiO2NT was dispersed in 20 mL of ethanol and stirred until homogeneous. Then, 20 mL of Fe(NO3)3·9H2O solution was added dropwise while stirring. The resulting mixture was dissolved and heat-treated at 150 °C for 8 hours, precipitated, washed, dried at 80 °C for 12 hours, and then annealed at 300 °C for 1 hour in a nitrogen stream to obtain Fe / TiO2NT.

[0072] Step 3: Preparation of APTS and MPS modified Fe / TiO2NT:

[0073] 0.5 g of Fe / TiO2NT was added to a 0.85 mol / L NaOH solution for pretreatment for 40 minutes to hydrolyze the TiO2NT surface to form Ti-OH groups. After washing and air drying, the treated 0.5 g of Fe / TiO2NT was immersed in anhydrous toluene solution containing 0.03 v / v of 3-aminopropyltriethoxysilane and 0.03 v / v of 3-methacryloyloxypropyltrimethoxysilane. The mixture was then purged with nitrogen for 30 minutes and heated at 50 °C for 5 hours. After washing and drying, APTS and MPS modified Fe / TiO2NT were obtained.

[0074] Step 4: Preparation of amino-modified styrene photosensitizer:

[0075] S1: Take 6g of 3,4-dihydroxybenzaldehyde, 5g of p-nitrobenzeneacetic acid, and 4.5mL of hexahydropyridine, mix them evenly, heat to 100℃ and react for 25h, filter, separate and purify, and recrystallize to obtain nitrated styrene photosensitizer.

[0076] S2: Add 1g of nitrated styrene photosensitizer, 20mL of deionized water, and 0.5g of platinum carbon catalyst to the reaction vessel, purge with nitrogen for 7min, raise the temperature to 50℃, heat for 23min, charge with 4MPaH2, and stir for 3.5h to obtain amino-modified styrene photosensitizer.

[0077] Step 5: Preparation of modified Fe / TiO2NT:

[0078] Take 1g of APTS and MPS-modified Fe / TiO2NT and 0.3g of aminostyrene photosensitizer, heat to 80℃, mix evenly, and dry to obtain modified Fe / TiO2NT;

[0079] Step Six: Preparation of PFOA Photocatalytic Degradation Materials:

[0080] A template PFOA of 0.03 mol / L was added to a mixed solution of methanol / acetonitrile (1:1 volume ratio), 0.5 mol / L acrylamide, 1.5 mol / L ethylene glycol dimethacrylate, and 0.05 mol / L azobisisobutyronitrile (0.05 mol / L volume ratio). The mixture was ultrasonically mixed for 15 minutes to obtain a homogeneous solution. The solution was then dropped onto both sides of modified Fe / TiO2NT to obtain a uniform coating. The coating was then inserted into a columnar quartz tube, sealed, and purged with nitrogen for 25 minutes. Polymerization was carried out under 350 nm ultraviolet light for 10 hours. The substrate was then immersed in methanol / deionized water (1:1 volume ratio) to remove the molecular template, yielding the PFOA photocatalytic degradation material.

[0081] Example 5: Without amination modification of the styrene photosensitizer, the rest is the same as in Example 4. A method for preparing a photocatalytic material for degrading PFOA includes the following steps:

[0082] Step 1: Preparation of TiO2NT:

[0083] In a cylindrical electrochemical reactor with a DC power supply, titanium foil was used as the anode and graphite sheet as the cathode. Magnetic stirring was performed at 25°C, and a constant voltage of 15V was applied to an electrolyte containing 0.09 mol / L ethylene glycol and 0.45 mol / L ammonium fluoride. After anodic oxidation at 15°C for 6 hours, the product was rinsed with deionized water, dried, and annealed at 400°C to obtain TiO2NT.

[0084] Step 2: Preparation of Fe / TiO2NT:

[0085] 0.5 g TiO2NT was dispersed in 20 mL of ethanol and stirred until homogeneous. Then, 20 mL of Fe(NO3)3·9H2O solution was added dropwise while stirring. The resulting mixture was dissolved and heat-treated at 150 °C for 8 hours, precipitated, washed, dried at 80 °C for 12 hours, and then annealed at 300 °C for 1 hour in a nitrogen stream to obtain Fe / TiO2NT.

[0086] Step 3: Preparation of APTS and MPS modified Fe / TiO2NT:

[0087] 0.5 g of Fe / TiO2NT was added to a 0.85 mol / L NaOH solution for pretreatment for 40 minutes to hydrolyze the TiO2NT surface to form Ti-OH groups. After washing and air drying, the treated 0.5 g of Fe / TiO2NT was immersed in anhydrous toluene solution containing 0.03 v / v of 3-aminopropyltriethoxysilane and 0.03 v / v of 3-methacryloyloxypropyltrimethoxysilane. The mixture was then purged with nitrogen for 30 minutes and heated at 50 °C for 5 hours. After washing and drying, APTS and MPS modified Fe / TiO2NT were obtained.

[0088] Step 4: Preparation of nitrated styrene photosensitizer:

[0089] S1: Take 6g of 3,4-dihydroxybenzaldehyde, 5g of p-nitrobenzeneacetic acid, and 4.5mL of hexahydropyridine, mix them evenly, heat to 100℃ and react for 25h, filter, separate and purify, and recrystallize to obtain nitrated styrene photosensitizer.

[0090] Step 5: Preparation of modified Fe / TiO2NT:

[0091] Take 1g of Fe / TiO2NT and 0.3g of nitrated styrene photosensitizer, heat to 80℃, mix evenly, and dry to obtain modified Fe / TiO2NT;

[0092] Step Six: Preparation of PFOA Photocatalytic Degradation Materials:

[0093] A template PFOA of 0.03 mol / L was added to a mixed solution of methanol / acetonitrile (1:1 volume ratio), 0.5 mol / L acrylamide, 1.5 mol / L ethylene glycol dimethacrylate, and 0.05 mol / L azobisisobutyronitrile (0.05 mol / L volume ratio). The mixture was ultrasonically mixed for 15 minutes to obtain a homogeneous solution. The solution was then dropped onto both sides of modified Fe / TiO2NT to obtain a uniform coating. The coating was then inserted into a columnar quartz tube, sealed, and purged with nitrogen for 25 minutes. Polymerization was carried out under 350 nm ultraviolet light for 10 hours. The substrate was then immersed in methanol / deionized water (1:1 volume ratio) to remove the molecular template, yielding the PFOA photocatalytic degradation material.

[0094] Comparative Example 1: A method for preparing a photocatalytic degradation material, comprising the following steps:

[0095] Step 1: Preparation of TiO2NT:

[0096] In a cylindrical electrochemical reactor with a DC power supply, titanium foil was used as the anode and graphite sheet as the cathode. Magnetic stirring was performed at 25°C, and a constant voltage of 15V was applied to an electrolyte containing 0.09 mol / L ethylene glycol and 0.45 mol / L ammonium fluoride. After anodic oxidation at 15°C for 6 hours, the product was rinsed with deionized water, dried, and annealed at 400°C to obtain TiO2NT.

[0097] Step 2: Preparation of Fe / TiO2NT:

[0098] 0.5 g TiO2NT was dispersed in 20 mL of ethanol and stirred until homogeneous. Then, 20 mL of Fe(NO3)3·9H2O solution was added dropwise while stirring. The resulting mixture was dissolved and heat-treated at 150 °C for 8 hours, precipitated, washed, dried at 80 °C for 12 hours, and then annealed at 300 °C for 1 hour in a nitrogen stream to obtain Fe / TiO2NT.

[0099] Step 3: Preparation of APTS and MPS modified Fe / TiO2NT:

[0100] 0.5 g of Fe / TiO2NT was added to a 0.85 mol / L NaOH solution for pretreatment for 40 minutes to hydrolyze the TiO2NT surface to form Ti-OH groups. After washing and air drying, the treated 0.5 g of Fe / TiO2NT was immersed in anhydrous toluene solution containing 0.03 v / v of 3-aminopropyltriethoxysilane and 0.03 v / v of 3-methacryloyloxypropyltrimethoxysilane. The mixture was then purged with nitrogen for 30 minutes and heated at 50 °C for 5 hours. After washing and drying, APTS and MPS modified Fe / TiO2NT were obtained.

[0101] Step 4: Preparation of PFOA photocatalytic degradation materials:

[0102] A template perfluorooctane sulfonyl compound with a concentration of 0.03 mol / L was added to a mixed solution of methanol / acetonitrile (1:1 volume ratio), 0.5 mol / L acrylamide, 1.5 mol / L ethylene glycol dimethacrylate, and 0.05 mol / L azobisisobutyronitrile (0.05 mol / L volume ratio). The mixture was ultrasonically mixed for 15 minutes to obtain a homogeneous solution. The solution was then dropped onto both sides of APTS and MPS-modified Fe / TiO2NT to obtain a uniform coating. The coating was then inserted into a columnar quartz tube, sealed, and purged with nitrogen for 25 minutes. Polymerization was carried out under 350 nm ultraviolet light for 10 hours. The material was then immersed in methanol / deionized water (1:1 volume ratio) to remove the molecular template, yielding a photocatalytic degradation material.

[0103] Comparative Example 2: Preparation of Fe / TiO2NT photocatalytic degradation material, the rest is the same as in Example 1:

[0104] Step 1: Preparation of TiO2NT:

[0105] In a cylindrical electrochemical reactor with a DC power supply, titanium foil was used as the anode and graphite sheet as the cathode. Magnetic stirring was performed at 25°C, and a constant voltage of 15V was applied to an electrolyte containing 0.09 mol / L ethylene glycol and 0.45 mol / L ammonium fluoride. After anodic oxidation at 15°C for 6 hours, the product was rinsed with deionized water, dried, and annealed at 400°C to obtain TiO2NT.

[0106] Step 2: Preparation of Fe / TiO2NT photocatalytic degradation material:

[0107] 0.5 g TiO2NT was dispersed in 20 mL of ethanol and stirred until homogeneous. Then, 20 mL of Fe(NO3)3·9H2O solution was added dropwise while stirring. The resulting mixture was heat-treated at 150 °C for 8 hours, precipitated, washed, dried at 80 °C for 12 hours, and then annealed at 300 °C for 1 hour in a nitrogen atmosphere to obtain Fe / TiO2NT photocatalytic degradation material.

[0108] experiment:

[0109] The photocatalytic degradation materials prepared in Examples 1-3 and Comparative Examples 1-2 were used for performance testing. The photocatalytic reactor was a 200 mL open quartz beaker with a cooling water jacket, an inner diameter of 60 mm, and an outer diameter of 80 mm; a light intensity of 125 W, a center wavelength of 365 nm, and a light intensity of 5.3 mW·cm⁻¹ was used. 2 A high-pressure mercury lamp was placed parallel to the reactor for irradiation. The same mass of 0.5 g / L of photocatalyst was added to 150 mL and 50 mg / L PFOA solutions, respectively. The irradiation reaction was carried out for 10 hours, and the change in PFOA concentration was measured to characterize the photodegradation efficiency.

[0110]

[0111] Conclusion: As shown in the table, under the same conditions, the PFOA degradation efficiency of the catalysts in Examples 1-3 is higher than that of Comparative Examples 1-2. Under 10 hours of UV radiation, the PFOA photodegradation efficiency of the photocatalyst in Example 1 reached 92%, the photodegradation efficiency of the photocatalyst in Comparative Example 1 was 82%, and the photodegradation efficiency of the photocatalyst in Comparative Example 2 was 61%. This demonstrates that the photocatalytic material of TiO2NT co-modified with Fe and MIP produced in this invention has high PFOA selective adsorption and photodegradation efficiency. Example 4 further modified Fe / TiO2NT using an aminostyrene photosensitizer, and Example 5 modified it using a nitrostyrene photosensitizer. As shown in the table, the amino groups on the Fe / TiO2NT modified in Example 4 have good compatibility with the amide groups on the molecularly imprinted polymer prepared in this invention, further improving the degradation efficiency, with a photodegradation efficiency of 97%, which is superior to that of Example 5.

[0112] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a photocatalytic material for degrading PFOA, characterized in that: Includes the following steps: Step 1: Disperse TiO2NT in ethanol and stir until homogeneous. Then, add Fe(NO3)3·9H2O solution dropwise while stirring. Heat treat at 150-160℃ for 8-9 hours, precipitate, wash, dry, and then anneal at 300-320℃ for 1-2 hours in a nitrogen atmosphere to obtain Fe / TiO2NT. Step 2: Add Fe / TiO2NT to NaOH solution for pretreatment for 40-60 minutes, wash and dry, then immerse the treated Fe / TiO2NT in anhydrous toluene solution containing 3-aminopropyltriethoxysilane and 3-methacryloyloxypropyltrimethoxysilane, purge with nitrogen, heat at 50-55℃ for 5-6 hours, wash and dry to obtain modified Fe / TiO2NT; Step 3: Drop the molecularly imprinted polymer mixture onto both sides of the modified Fe / TiO2NT, then insert it into a quartz tube, seal it, and purge it with nitrogen for 25-30 minutes. Irradiate it with ultraviolet light for 10-11 hours, then wash it to obtain the PFOA photocatalytic degradation material. In step three, the modified Fe / TiO2NT is further modified by taking the modified Fe / TiO2NT and amino-modified styrene photosensitizer, heating to 80-85℃, mixing evenly, and drying to obtain modified Fe / TiO2NT. The preparation method of the amino-modified styrene photosensitizer is as follows: Includes the following steps: S1: Take 3,4-dihydroxybenzaldehyde, p-nitrobenzyl acetic acid and hexahydropyridine, mix them evenly, heat to 100-105℃ and react for 24-26 h, filter, separate and purify, recrystallize to obtain nitrated styrene photosensitizer; S2: Add nitrated styrene photosensitizer, deionized water, and platinum-carbon catalyst to the reactor, purge with nitrogen for 5-10 min, raise the temperature to 50-55℃, heat for 20-25 min, introduce 4MPaH2, and stir the reaction for 3-3.5 h to obtain amino-modified styrene photosensitizer. In step three, the preparation method of the molecularly imprinted polymer mixture is as follows: perfluorooctanoic acid is added to a mixed solution of methanol and acetonitrile, acrylamide, ethylene glycol dimethacrylate and azobisisobutyronitrile, and ultrasonically mixed evenly to obtain the molecularly imprinted polymer mixture. PFOA stands for perfluorooctanoic acid.

2. The method for preparing a photocatalytic material for degrading PFOA according to claim 1, characterized in that: In step one, the preparation method of TiO2NT is as follows: using titanium foil as the anode and graphite sheet as the cathode, magnetic stirring is performed at 25-30℃, and a constant voltage is applied in an electrolyte of ethylene glycol and ammonium fluoride. The mixture is then anolyzed, washed, dried, and annealed to obtain TiO2NT.

3. The method for preparing a photocatalytic material for degrading PFOA according to claim 2, characterized in that: The titanium foil has a purity of 99.5% and a thickness of 0.1-0.2 mm.

4. The method for preparing a photocatalytic material for degrading PFOA according to claim 2, characterized in that: The anodizing temperature is 15-17℃ and the time is 6-7 hours; the annealing temperature is 400-420℃ and the time is 1-3 hours.

5. The method for preparing a photocatalytic material for degrading PFOA according to claim 1, characterized in that: The concentrations of perfluorooctanoic acid (PFOA) are 0.03-0.04 mol / L, acrylamide is 0.5-0.6 mol / L, ethylene glycol dimethacrylate is 1.5-1.7 mol / L, and azobisisobutyronitrile (AIBN) is 0.05 mol / L.

6. The method for preparing a photocatalytic material for degrading PFOA according to claim 1, characterized in that: The volume ratio of methanol to acetonitrile is 1:

1.

7. A PFOA photocatalytic degradation material prepared by the preparation method of a photocatalytic material for degrading PFOA according to any one of claims 1-6.

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