Catalyst material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer material preparation and radioactive wastewater treatment, in particular to a catalyst material as well as a preparation method and application thereof. The material of the catalyst is a metal phthalocyanine polymer, and the structural formula is as shown in formula I: # imgabs0. The metal phthalocyanine polymer disclosed by the invention is a material with unique photoelectric properties and chemical stability, so that the metal phthalocyanine polymer shows many advantages in photocatalytic reduction of uranium (reduction of hexavalent soluble uranium into tetravalent uranium with low solubility). The metal phthalocyanine polymer disclosed by the invention has very high thermal stability and can resist high temperature, so that the durability and effectiveness of the metal phthalocyanine polymer under different temperature conditions are ensured. In addition, the metal phthalocyanine polymer provided by the invention has a wide absorption spectrum range, especially in visible light and near-infrared regions, so that the metal phthalocyanine polymer becomes an excellent photosensitive material and can efficiently capture sunlight, thereby improving the photocatalytic efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of polymer material preparation and radioactive wastewater treatment, and in particular to a catalyst material and a preparation method and application thereof. Background Art

[0002] With the widespread use of nuclear energy, the generation of radioactive wastewater is inevitable. These wastewaters contain various radioactive isotopes, such as uranium, plutonium and strontium, which pose a potential threat to the environment and human health. Traditional wastewater treatment methods include physical, chemical and biological methods. Physical methods mainly include evaporation, centrifugal separation and ion exchange; chemical methods involve precipitation, redox and solvent extraction; biological methods use the metabolic activities of microorganisms to remove radioactive substances. However, these methods have their own advantages and disadvantages, such as high treatment costs, complex operations, and secondary pollution risks.

[0003] Photocatalysis is an advanced environmental protection technology that uses light energy to stimulate catalysts to produce redox reactions. Under light, the catalyst absorbs photons, excites electrons to jump from the valence band to the conduction band, and generates electron-hole pairs. These high-energy electrons and holes can react with pollutants to achieve the purpose of degradation. However, the current method of photocatalytic reduction of uranium to treat wastewater has problems such as low catalyst efficiency, insufficient activity in the visible light range, and poor stability.

[0004] Therefore, providing a metal phthalocyanine polymer with a wide light absorption range, strong stability and high catalytic efficiency for photocatalytic reduction of uranium treatment wastewater is of great significance to the field of radioactive wastewater treatment. Summary of the invention

[0005] Based on the above content, the present invention provides a catalyst material (metal phthalocyanine polymer) with a wide light absorption range and good stability, and a preparation method and application thereof.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is a metal phthalocyanine polymer, the structural formula of which is shown in Formula I:

[0008]

[0009] In formula I, R is O and / or S;

[0010] R 1 is a substituent selected from At least one of;

[0011] M is a metal, and is at least one selected from cobalt (Co), nickel (Ni), and copper (Cu).

[0012] The second technical solution of the present invention is a method for preparing the above-mentioned metal phthalocyanine polymer, comprising the following steps:

[0013] Adding the compound of formula II and a metal salt into a solvent, reacting to completion under the conditions of a catalyst and a nitrogen atmosphere to obtain the metal phthalocyanine polymer;

[0014]

[0015] In formula II, R is O and / or S; R 1 for

[0016] The metal salt is one of metal nitrate, sulfate, acetate, hydrochloride and phosphate; the metal is cobalt, nickel or copper.

[0017] The third technical solution of the present invention is a photocatalyst, the raw materials of which include the above-mentioned metal phthalocyanine polymer.

[0018] A fourth technical solution of the present invention is the use of the above-mentioned metal phthalocyanine polymer or the above-mentioned photocatalyst in the photocatalytic reduction of hexavalent uranium to tetravalent uranium.

[0019] A fifth technical solution of the present invention is a method for reducing hexavalent uranium in uranium-containing wastewater into tetravalent uranium, wherein the above-mentioned metal phthalocyanine polymer or the above-mentioned photocatalyst is added to the uranium-containing wastewater for irradiation with ultraviolet or visible light (300-700nm), thereby reducing the hexavalent uranium in the uranium-containing wastewater into tetravalent uranium.

[0020] The present invention discloses the following technical effects:

[0021] The present invention optimizes the central metal ion and peripheral substituents of the metal phthalocyanine polymer to enhance the molecular dipole moment, so that the central metal atom provides more electrons for the phthalocyanine ring, thereby constructing an intramolecular electric field inside the metal phthalocyanine polymer and accelerating charge transfer. These are beneficial to the transfer of electrons and further to the photocatalytic reduction of hexavalent uranium.

[0022] The metal phthalocyanine polymer of the present invention is a material with unique photoelectric properties and chemical stability, and thus shows many advantages in the photocatalytic reduction of uranium (reducing hexavalent soluble uranium to low-soluble tetravalent uranium). The metal phthalocyanine polymer of the present invention has high thermal stability and can withstand high temperatures, ensuring its durability and effectiveness under different temperature conditions. In addition, the metal phthalocyanine polymer of the present invention has a wide range of absorption spectra, especially in the visible light region, which makes it an excellent photosensitive material that can efficiently capture sunlight, thereby improving photocatalytic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is the infrared spectrum of the metal phthalocyanine polymer obtained in Example 1 of the present invention.

[0025] Figure 2 This is the ultraviolet absorption spectrum of the metal phthalocyanine polymer obtained in Example 1 of the present invention.

[0026] Figure 3 This is a thermogravimetric curve of the metal phthalocyanine polymer obtained in Example 1 of the present invention.

[0027] Figure 4 This is a graph showing the removal rate of uranyl in wastewater by the metal phthalocyanine polymer PcPNi obtained in Example 1 of the present invention under different pH conditions.

[0028] Figure 5 This is the cycle test result of the metal phthalocyanine polymer PcPNi obtained in Example 1 of the present invention.

[0029] Figure 6 The removal rates of uranyl in wastewater by the metal phthalocyanine polymers PcPNi, PcPCo and PcPCu obtained in Example 1 of the present invention at pH=5 are shown. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0031] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0032] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0033] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0034] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0035] The first aspect of the present invention provides a metal phthalocyanine polymer, the structural formula of which is shown in Formula I:

[0036]

[0037] In formula I, R is O and / or S;

[0038] R 1 is a substituent selected from At least one of;

[0039] M is a metal, and is at least one selected from cobalt (Co), nickel (Ni), and copper (Cu).

[0040] The second aspect of the present invention provides a method for preparing the above-mentioned metal phthalocyanine polymer, comprising the following steps:

[0041] Adding the compound of formula II and a metal salt into a solvent, reacting to completion under the conditions of a catalyst and a nitrogen atmosphere to obtain the metal phthalocyanine polymer;

[0042]

[0043] In formula II, R is O and / or S; R 1 for

[0044] The metal salt is one of metal nitrate, sulfate, acetate, hydrochloride and phosphate; the metal is cobalt, nickel or copper.

[0045] In the present invention, the molar ratio of the compound of the structure shown in Formula II to the metal salt is 2:1.

[0046] In the present invention, the catalyst is 1,8-diazabicyclo[5.4.0]undec-7-ene; the amount of the catalyst used is 0.5% to 1% of the volume of the solvent.

[0047] In the present invention, the reaction temperature is 120-160° C. and the reaction time is 24-26 hours.

[0048] In the present invention, the solvent is a high boiling point alcohol reagent (BP>135° C.), for example, the solvent may be n-pentanol.

[0049] In the present invention, after the reaction is completed, the steps of filtering, washing and vacuum drying are also included.

[0050] The metal phthalocyanine polymer prepared by the solvothermal method of the present invention has the advantages of being reusable, having good thermal stability, having strong light absorption capacity, etc., and can be used for photocatalytic reduction of uranium-containing wastewater to achieve efficient removal of uranyl ions in the wastewater.

[0051] In the present invention, when R in Formula I is an oxygen atom, R 1 for When the metal salt is a nickel salt, the preparation method of the metal phthalocyanine polymer of the above structure comprises the following steps: 4,4'-bis-(3,4-dicyanophenoxy)diphenyl sulfone is prepared by reacting 4-nitrophthalonitrile and 4,4'-sulfonyldiphenol, and 4,4'-bis-(3,4-dicyanophenoxy)diphenyl sulfone and a nickel salt are reacted in the presence of an appropriate amount of a catalyst to prepare a nickel phthalocyanine polymer.

[0052] Further, when preparing 4,4'-bis-(3,4-dicyanophenoxy)diphenyl sulfone, the catalyst used is K 2 CO 3 The reaction temperature is 25-45°C, preferably 30°C, the reaction time is 24 hours, and the solvent used in the reaction is dimethylformamide (DMF).

[0053] Furthermore, when preparing nickel phthalocyanine polymer, the catalyst used is DBU, the reaction temperature is 120-160° C., preferably 140° C., the reaction time is 24-26 hours, the solvent used in the reaction is n-pentanol, and the nickel salt is nickel chloride hexahydrate.

[0054] In the present invention, when R in Formula I is an oxygen atom, R 1 for When the metal salt is a nickel salt, the preparation method of the metal phthalocyanine polymer of the above structure comprises the following steps: 4,4'-((thiobis(4,1-phenylene))bis(oxy))dibenzonitrile is prepared by reacting 4-nitrophthalonitrile and 4,4'-dihydroxydiphenyl sulfide, and 4,4'-((thiobis(4,1-phenylene))bis(oxy))dibenzonitrile is reacted with a nickel salt in the presence of an appropriate amount of catalyst to prepare a metal phthalocyanine polymer.

[0055] Further, when preparing 4,4'-((thiobis(4,1-phenylene))bis(oxy))dibenzonitrile, the catalyst used is K 2 CO 3 The reaction temperature is 25-45°C, preferably 30°C, the reaction time is 24 hours, and the solvent used in the reaction is dimethylformamide (DMF).

[0056] Furthermore, when preparing the metal phthalocyanine polymer, the catalyst used is DBU, the reaction temperature is 120-160° C., preferably 150° C., the reaction time is 24-26 hours, the solvent used in the reaction is n-pentanol, and the nickel salt is nickel chloride hexahydrate.

[0057] The synthetic route is as follows:

[0058]

[0059] In the present invention, when R in Formula I is a sulfur atom, R 1 for When the metal salt is a nickel salt, the preparation method of the metal phthalocyanine polymer of the above structure comprises the following steps: 2,4'-bis-(3,4-dicyanophenylthio)thiadiazole is prepared by reacting 4-nitrophthalonitrile and 2,5-dimercaptothiadiazole, and 2,4'-bis-(3,4-dicyanophenylthio)thiadiazole and a nickel salt are reacted in the presence of an appropriate amount of catalyst to prepare a nickel phthalocyanine polymer.

[0060] Further, when preparing 2,4'-bis-(3,4-dicyanophenylthio)thiadiazole, the catalyst used is K 2 CO 3 The reaction temperature is 25-45°C, preferably 30°C, the reaction time is 24 hours, and the solvent used in the reaction is dimethylformamide (DMF).

[0061] Furthermore, when preparing nickel phthalocyanine polymer, the catalyst used is DBU, the reaction temperature is 120-160° C., preferably 135° C., the reaction time is 24-26 hours, the solvent used in the reaction is n-pentanol, and the nickel salt is nickel chloride hexahydrate.

[0062] The synthetic route is as follows:

[0063]

[0064] The third aspect of the present invention provides a photocatalyst, the raw material of which includes the above-mentioned metal phthalocyanine polymer.

[0065] The fourth aspect of the present invention provides the use of the metal phthalocyanine polymer or the photocatalyst in the photocatalytic reduction of hexavalent uranium to tetravalent uranium.

[0066] In the present invention, the metal phthalocyanine polymer or the photocatalyst can reduce hexavalent uranium to tetravalent uranium.

[0067] A fifth aspect of the present invention provides a method for reducing hexavalent uranium in uranium-containing wastewater into tetravalent uranium, wherein the above-mentioned metal phthalocyanine polymer or the above-mentioned photocatalyst is added to the uranium-containing wastewater and irradiated with ultraviolet or visible light (300-700nm), so that the hexavalent uranium in the uranium-containing wastewater can be reduced to tetravalent uranium.

[0068] In the present invention, the concentration of the metal phthalocyanine polymer in the uranium-containing wastewater is 0.2-0.5 mg / mL; the concentration of the photocatalyst in the uranium-containing wastewater is 0.2-0.5 mg / mL.

[0069] The invention optimizes the central metal ion and peripheral substituents of the metal phthalocyanine polymer to enhance the intramolecular electric field constructed inside the metal phthalocyanine polymer. The metal phthalocyanine polymer has high thermal stability, can tolerate acid environments, ensures its durability and effectiveness under different reaction conditions, and can be used for photocatalytic reduction of uranium (VI) in wastewater.

[0070] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art; the reagents or raw materials used, unless otherwise specified, are all commercially available products or can be prepared by known methods.

[0071] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0072] Example 1: Preparation and characterization of metal phthalocyanine polymers

[0073] Step 1, under nitrogen atmosphere, 4-nitrophthalonitrile (2mmol, 346mg) and 4,4'-sulfonyldiphenol (1mmol, 250mg) were added to a round-bottom flask, dissolved with 15ml dimethylformamide (DMF), potassium carbonate (3mmol, 414mg) was added, and the reaction solution was reacted at 30°C for 24h; after the reaction, the reaction solution was poured into a 1mol / L dilute hydrochloric acid solution, filtered, and the solid was washed three times with deionized water, and then vacuum dried for 24 hours. The crude product was purified by silica gel chromatography column (mobile phase: ethyl acetate: petroleum ether: dichloromethane = 1:2:6) to obtain a white pure compound 4,4'-bis-(3,4-dicyanophenoxy) diphenyl sulfone (455.3mg, 76.4% yield)

[0074] Step 2, add 4,4'-bis-(3,4-dicyanophenoxy)diphenyl sulfone (0.258mmol, 130mg) and nickel chloride hexahydrate (0.13mmol, 31mg) into a round-bottom flask containing 20ml of n-pentanol, add 0.15ml of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) under a nitrogen atmosphere, and react at 140°C for 24h. After the reaction, the reaction solution was filtered to obtain a green solid powder, which was washed with methanol, ethyl acetate, and deionized water respectively, and vacuum dried for 24h to obtain 70mg of the product PcPNi (nickel phthalocyanine polymer), with a yield of 43.5%. The synthesis of cobalt or copper phthalocyanine polymer (PcPCo or PcPCu) is similar to that of PcPNi, NiCl 2 6H 2 O is only replaced by Co(NO 3 ) 2 6H 2 O or Cu(CH 3 COOH)·H 2 O replacement (yield: PcPCo 53% and PcPCu 60.6%)

[0075] The synthetic route of PcPNi in this embodiment is as follows:

[0076]

[0077] Fourier transform infrared spectroscopy (FT-IR) was used to characterize the metal phthalocyanine polymers. Figure 1 This is the infrared spectrum of metal phthalocyanine polymer (in the figure, PSCN represents 4,4'-bis-(3,4-dicyanophenoxy)diphenyl sulfone). Figure 1 It can be seen that the infrared spectrum of PcPNi is at 1720cm -1 and 1580cm -1 New absorption bands appeared at 1320 cm-1, corresponding to the C=N bending vibration and C=C vibration in phthalocyanine, respectively.-1 and 1150cm -1 The peak at 2240-2220cm is the characteristic absorption peak of O=S=O, while -1 The peak of cyano group disappears, indicating that the metal phthalocyanine polymer is successfully prepared in the present invention.

[0078] Figure 2 is the ultraviolet absorption spectrum of metal phthalocyanine polymer, Figure 2 It can be seen that there are obvious absorption peaks at 300-400nm and 600-700nm, which belong to the B band and Q band of phthalocyanine polymer respectively.

[0079] Figure 3 is the thermogravimetric diagram of the metal phthalocyanine polymer, Figure 3 It can be seen that metal phthalocyanine polymers have good thermal stability below 300°C.

[0080] Example 2: Photocatalytic reduction of UO in uranium-containing wastewater by nickel phthalocyanine polymer 2 2+ Applications

[0081] A 350W xenon lamp equipped with a 420nm filter was used as a visible light source. 10 mg of the nickel phthalocyanine polymer solid powder prepared in Example 1 was placed in 50 mL of 50 ppm UO 2 2+ Solution (UO was prepared by dissolving uranyl nitrate in a mixture of deionized water and ethanol (hole sacrificial agent) in a volume ratio of 25:1 2 2+ solution); dilute nitric acid and sodium carbonate were used to adjust the solution pH. Before irradiation, the dark reaction was carried out for 1 h to reach adsorption-desorption equilibrium; then, under simulated sunlight, samples were taken every 30 minutes (irradiation for 4 hours), and the samples were analyzed for UO at a wavelength of 650 nm. 2 2+ The absorbance intensity at different irradiation times is converted into UO 2 2+ removal rate.

[0082] Figure 4 is the photocatalytic effect of nickel phthalocyanine polymer on the removal of uranyl from wastewater at different pH values; Figure 4 It can be seen that at pH = 5, the UO 2 2+ The photocatalytic reduction effect can reach 91.6%.

[0083] Example 3: Photocatalytic reduction of UO in uranium-containing wastewater by nickel phthalocyanine polymer 2 2+ Recycling in

[0084] A 350W xenon lamp equipped with a 420nm filter was used as a visible light source. 10mg of the nickel phthalocyanine polymer solid powder prepared in Example 1 was placed in 50mL of 50ppm UO 2 2+ Solution (UO was prepared by dissolving uranyl nitrate in a mixture of deionized water and ethanol in a volume ratio of 25:1 2 2+ solution); dilute nitric acid and sodium carbonate were used to adjust the solution pH to 5. Then, the sample was irradiated under simulated sunlight for 4 hours, and the UO 2 2+ The absorbance intensity at different irradiation times is converted into UO 2 2+ After the photocatalytic experiment, the photocatalyst was collected and placed in 3 mol / L sodium carbonate for 3 h. Subsequently, the photocatalyst was repeatedly washed with deionized water and dried for cyclic testing.

[0085] Figure 5 It is nickel phthalocyanine polymer at pH = 5, 50ppm UO 2 2+ Photocatalytic reduction cycle test effect diagram in solution, by Figure 5 It can be seen that after 3 cycles of testing, the performance decreased by 4.55%.

[0086] Figure 6 The PcPCo and PcPCu prepared in Example 1 were subjected to the same effect verification as in Example 2. The results showed that at pH = 5, PcPCo had a significant effect on the UO 2 2+ The photocatalytic reduction effect of PcPCu on UO in wastewater can reach 83.20%. 2 2+ The photocatalytic reduction effect can reach 63.11%.

[0087] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A metal phthalocyanine polymer, characterized in that The structural formula is shown in Formula I: In formula I, R is O and / or S; R1 is a substituent selected from At least one of; M is a metal, selected from at least one of cobalt, nickel and copper.

2. A method for preparing the metal phthalocyanine polymer according to claim 1, characterized in that: The following steps are involved: Adding the compound of formula II and a metal salt into a solvent, reacting to completion under the conditions of a catalyst and a nitrogen atmosphere to obtain the metal phthalocyanine polymer; In formula II, R is O and / or S; R1 is The metal salt is one of metal nitrate, sulfate, acetate, hydrochloride and phosphate; the metal is cobalt, nickel or copper.

3. The preparation method according to claim 2, characterized in that: The molar ratio of the compound with the structure shown in formula II to the metal salt is 2:

1.

4. The preparation method according to claim 2, characterized in that: The catalyst is 1,8-diazabicyclo[5.4.0]undec-7-ene; the amount of the catalyst used is 0.5% to 1% of the volume of the solvent.

5. The preparation method according to claim 2, characterized in that: The reaction temperature is 120-160° C. and the reaction time is 24-26 hours.

6. A photocatalyst, characterized in that: The raw material comprises the metal phthalocyanine polymer as claimed in claim 1.

7. Use of the metal phthalocyanine polymer according to claim 1 or the photocatalyst according to claim 6 in the photocatalytic reduction of hexavalent uranium to tetravalent uranium.

8. A method for reducing hexavalent uranium in uranium-containing wastewater to tetravalent uranium, characterized in that: The metal phthalocyanine polymer described in claim 1 or the photocatalyst described in claim 6 is added to uranium-containing wastewater and irradiated with ultraviolet or visible light, so that the hexavalent uranium in the uranium-containing wastewater can be reduced to tetravalent uranium.

9. The method for reducing hexavalent uranium to tetravalent uranium in uranium-containing wastewater according to claim 8, characterized in that: The concentration of metal phthalocyanine polymer in uranium-containing wastewater is 0.2-0.5 mg / mL; the concentration of photocatalyst in uranium-containing wastewater is 0.2-0.5 mg / mL.

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