A nickel porphyrin-based hydrogen-bonded organic framework heterojunction material and its preparation method and application

Abstract

The present invention belongs to the technical field of material chemistry, and specifically relates to a nickel porphyrin-based hydrogen bond organic framework heterojunction material and its preparation method and application. The nickel porphyrin-based hydrogen bond organic framework heterojunction material adopts cadmium sulfide (CdS) as a substrate, in-situ growth of nickel porphyrin-based hydrogen bond organic framework material, and the nickel porphyrin-based hydrogen bond organic framework heterojunction material (CdS x @Ni‑pHOF). In air atmosphere, CdS x @Ni‑pHOF has excellent photocatalytic reduction ability for hexavalent uranium without the need for hole traps, exhibits good resistance to interfering ions, and demonstrates excellent uranium removal ability in the treatment of real uranium-containing radioactive wastewater.

Description

Technical Field

[0001] The present invention belongs to the technical field of material chemistry, and in particular relates to a nickel porphyrin-based hydrogen-bonded organic framework heterojunction material, a preparation method thereof, and application thereof in the treatment of wastewater containing radioactive uranium. Background Art

[0002] Nuclear energy is a vital component of basic energy, offering advantages such as high efficiency, low pollution, and environmental friendliness. Uranium is the primary nuclear fuel used in nuclear power plants, but uranium mining inevitably produces radioactive wastewater. Therefore, the enrichment and recovery of uranium from uranium-containing radioactive wastewater is crucial for environmental protection and the long-term development of nuclear energy. Photocatalysis is considered a promising separation method, using visible light to generate electrons on the catalyst surface, reducing soluble U(VI) to an insoluble U(IV) precipitate.

[0003] Currently, most catalysts used for photocatalytic removal of U(VI) face two unresolved challenges: first, photocatalysis requires oxygen-free conditions, as oxygen in the air readily reoxidizes the reduced U(IV) to U(VI); and second, the use of organic reagents such as methanol as hole scavengers, due to the easy recombination of photogenerated electrons and holes during the photocatalytic process, preventing the photogenerated electrons from fully participating in the reduction process. Purposefully constructing heterojunctions not only enhances the catalyst's ability to separate electrons and holes but also prevents oxygen from entering the reducing end and interfering with the reduction of U(VI). Summary of the Invention

[0004] The purpose of the present invention is to provide a nickel-porphyrin-based hydrogen-bonded organic framework heterojunction material and its preparation method and application; the nickel-porphyrin-based hydrogen-bonded organic framework heterojunction material selects cadmium sulfide as a substrate to in-situ grow the nickel-porphyrin-based hydrogen-bonded organic framework material to construct a heterojunction structure, and in an air atmosphere, uranium can be removed from uranium-containing radioactive wastewater without a hole capture agent.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing a nickel porphyrin-based hydrogen-bonded organic framework heterojunction material comprises the following steps:

[0007] Step 1: Preparation of cadmium sulfide;

[0008] Cadmium acetate dihydrate and thiourea in a mass ratio of 1:1-5 are ultrasonically dissolved in 30-80 parts by volume of deionized water for 10-60 minutes; the suspension is heated to 80-120°C for 6-10 hours; the suspension is cooled to room temperature, filtered, washed, and vacuum dried to obtain cadmium sulfide (CdS);

[0009] Step 2: Preparation of nickel porphyrin-based hydrogen-bonded organic framework heterojunction materials;

[0010] Take cadmium sulfide and 5,10,15,20-tetrakis(4-(2,4-diaminotriazine)phenyl)nickel porphyrin prepared in step 1 in different mass ratios, add them to 20-70 parts by volume of a mixed solvent, ultrasonicate for 10-30 minutes at room temperature, seal, heat to 100-180°C, heat for 60-90 hours; cool to room temperature, filter, wash, and vacuum dry to obtain nickel porphyrin-based hydrogen bonded organic framework heterojunction material CdS x @Ni-pHOF, the mass ratio x of cadmium sulfide and 5,10,15,20-tetrakis(4-(2,4-diaminotriazine)phenyl)nickelporphyrin is (0,1];

[0011] The mixed solvent is prepared by mixing o-dichlorobenzene, n-butanol and acetic acid in a volume ratio of 3:0.1-1.5:0.01-0.15, and the concentration of acetic acid is 4.5-7.5 mol / L.

[0012] Furthermore, the vacuum drying temperature is 60-90°C.

[0013] The present invention also provides a nickel-porphyrin-based hydrogen-bonded organic framework heterojunction material, and uses the nickel-porphyrin-based hydrogen-bonded organic framework heterojunction material in the treatment of uranium-containing radioactive wastewater; specifically, the nickel-porphyrin-based hydrogen-bonded organic framework heterojunction material is added to uranium-containing radioactive wastewater and a photocatalytic reaction is carried out under light irradiation, and the photocatalytic reduction and removal of hexavalent uranium in the uranium-containing radioactive wastewater is achieved in an air atmosphere without the need for a hole capture agent.

[0014] Furthermore, the solid-to-liquid ratio of the nickel porphyrin-based hydrogen-bonded organic framework heterojunction material to uranium-containing radioactive wastewater is 0.6 g / L.

[0015] Furthermore, the pH of the uranium-containing radioactive wastewater is adjusted to 5.

[0016] Furthermore, the concentration of hexavalent uranium in the uranium-containing radioactive wastewater is adjusted to 50 mg / L.

[0017] The beneficial effects of the present invention are: using cadmium sulfide (CdS) as a substrate, in situ growing nickel porphyrin-based hydrogen bond organic framework material, preparing nickel porphyrin-based hydrogen bond organic framework heterojunction material (CdS x @Ni-pHOF). In air atmosphere, CdS x @Ni-pHOF has excellent photocatalytic reduction ability for hexavalent uranium without the need for hole traps, exhibits good anti-interference ion ability, and shows excellent uranium removal ability in the treatment of real uranium-containing radioactive wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 CdS x@XRD patterns of Ni-pHOF, CdS and Ni-pHOF.

[0019] Figure 2 CdS under different gas atmospheres 0.67 @Ni-pHOF photocatalytic removal effect of U(VI) under light conditions.

[0020] Figure 3 CdS x @Photocatalytic removal effect of Ni-pHOF, CdS and Ni-pHOF on U(VI) under light conditions.

[0021] Figure 4 CdS under different solid-liquid ratios 0.67 @Ni-pHOF photocatalytic removal effect of U(VI).

[0022] Figure 5 CdS under different pH conditions 0.67 @Ni-pHOF photocatalytic removal effect of U(VI).

[0023] Figure 6 CdS under different initial U(VI) concentrations 0.67 @Ni-pHOF photocatalytic removal effect of U(VI).

[0024] Figure 7 CdS in the presence of different cations 0.67 @Ni-pHOF photocatalytic removal effect of U(VI).

[0025] Figure 8 CdS in the presence of different anions 0.67 @Ni-pHOF photocatalytic removal effect of U(VI).

[0026] Figure 9 CdS 0.67 @Ni-pHOF photocatalytic removal effect of U(VI) over multiple cycles. DETAILED DESCRIPTION

[0027] Example 1

[0028] This embodiment provides a structurally stable nickel porphyrin-based hydrogen bond organic framework heterojunction material CdS 0.67 The preparation method of @Ni-pHOF comprises the following steps:

[0029] Step 1: Add 456.7 mg of cadmium acetate dihydrate and 533.0 mg of thiourea to 50 mL of deionized water and ultrasonicate for 60 minutes; place the suspension in a reactor, heat to 100°C and react for 8 hours; cool to room temperature, filter, wash with deionized water and ethanol, and vacuum dry to obtain cadmium sulfide.

[0030] Step 2: Place 18 mg of 5,10,15,20-tetrakis(4-(2,4-diaminotriazine)phenyl)nickel porphyrin, 12 mg of cadmium sulfide and 1.1 mL of a mixed solvent (o-dichlorobenzene: n-butanol: 6 mol / L acetic acid in a volume ratio of 3:1:0.1) in a pressure tube, ultrasonicate for 15 min at room temperature, seal, heat at 120 ° C for 72 h, cool to room temperature, filter, wash, and vacuum dry to obtain nickel porphyrin-based hydrogen bonded organic framework heterojunction material CdS 0.67 @Ni-pHOF.

[0031] Example 2

[0032] This embodiment provides a structurally stable nickel porphyrin-based hydrogen bond organic framework heterojunction material CdS x A preparation method of @Ni-pHOF, the amount of which is slightly different from that of step 2 of Example 1, specifically comprising: adding 30 mg of 5,10,15,20-tetrakis(4-(2,4-diaminotriazine)phenyl)nickelporphyrin and cadmium sulfide in different mass ratios to 1.1 mL of a mixed solvent (o-dichlorobenzene:n-butanol:6 mol / L acetic acid in a volume ratio of 3:1:0.1) in a pressure tube, ultrasonicating at room temperature for 15 min, and sealing; heating at 120°C for 72 h, cooling to room temperature, filtering, washing, and vacuum drying to obtain a nickel-porphyrin-based hydrogen-bonded organic framework heterojunction material CdSx@Ni-pHOF (x=0.05, 0.11, 0.25, 0.43, 0.1); wherein the value of x depends on the mass ratio of cadmium sulfide to 5,10,15,20-tetrakis(4-(2,4-diaminotriazine)phenyl)nickelporphyrin.

[0033] Comparative Example 1

[0034] This comparative example provides a method for preparing a porphyrin-based hydrogen-bonded organic framework material Ni-pHOF, comprising placing 30 mg of 5,10,15,20-tetrakis(4-(2,4-diaminotriazine)phenyl)nickel porphyrin and 1.1 mL of a mixed solvent (o-dichlorobenzene:n-butanol:6 mol / L acetic acid in a volume ratio of 3:1:0.1) in a 10 mL pressure tube, ultrasonicating at room temperature for 15 minutes, sealing, heating at 120° C. for 72 hours, cooling to room temperature, filtering, washing, and vacuum drying to obtain Ni-pHOF. The specific preparation method is disclosed in Chinese invention patent No. CN 117659432 B.

[0035] Using X-ray powder diffractometer to obtain CdS x @XRD patterns of Ni-pHOF, CdS and Ni-pHOF. Figure 1 As shown, with the CdS x As the CdS content in the @Ni-pHOF heterojunction increases, the XRD diffraction peak intensity corresponding to the Ni-pHOF position decreases, indicating that excessive CdS affects the formation of the hydrogen-bonded organic framework structure of nickel porphyrin.

[0036] Photocatalytic experiments (conducted in a PCX-50C Discover multi-channel photocatalytic reaction system)

[0037] First, take 30mgCdS x Ni-pHOF, CdS, and Ni-pHOF were added to a quartz photoreaction bottle and ultrasonically dispersed into 50 mL of hexavalent uranium U(VI) solution (concentration: 50 mg / L). The pH value was adjusted with a negligible volume of 0.1 mol / L NaOH or HCl solution.

[0038] Then, a 10W LED lamp was used to simulate sunlight for 240 minutes. Within a certain period of time, the photocatalyst was separated from the liquid phase, and the U(VI) concentration was measured at a wavelength of 651nm using an arsenazo III spectrophotometer UV-2450 ultraviolet-visible spectrophotometer to calculate the removal rate. This method evaluated the effects of different gas atmospheres, different CdS x @The effects of Ni-pHOF, different solid-liquid ratios, pH, initial U(VI) concentration and interfering ions on U(VI) removal performance.

[0039] Figure 2 CdS 0.67 @Ni-pHOFCdS in different gas atmospheres 0.67 @Ni-pHOF photocatalytic removal effect of U(VI); in air atmosphere, CdS 0.67 @Ni-pHOF photocatalytic reduction generates U(IV) precipitates that will not be oxidized to U(VI) by oxygen in the air.

[0040] Figure 3 CdS x @Ni-pHOF, CdS and Ni-pHOF photocatalytic removal of U(VI) under light conditions; With the increase of CdS content in the heterojunction, CdS x The photocatalytic removal rate of U(VI) by @Ni-pHOF gradually increases, which is due to the heterojunction structure that makes the photogenerated holes h + Heguangsheng Electronics e ‒When the CdS content in the heterojunction is higher than 50%, it will affect the formation of the hydrogen bond organic framework structure, break the intermolecular hydrogen bonds, and thus reduce the catalytic effect.

[0041] Figure 4 CdS under different solid-liquid ratio conditions (m / V=0.2, 0.4, 0.6, 0.8, 1.0g / L) 0.67 @Ni-pHOF photocatalytic removal effect of U(VI); Figure 4 It can be seen that excessive or insufficient photocatalyst dosage will significantly affect the photocatalytic removal rate of U(VI); after 240 minutes of illumination, CdS 0.67 When the @Ni-pHOF catalyst dosage was 0.6 g / L, the photocatalytic removal efficiency of U(VI) was the highest, which was 91.00%.

[0042] Figure 5 CdS under different pH conditions (pH=2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, m / V=0.6g / L) 0.67 @Ni-pHOF photocatalytic removal effect of U(VI); Figure 5 It can be seen that when the pH value of the solution increases from 2.0 to 5.0, CdS 0.67 The photocatalytic removal efficiency of U(VI) by @Ni-pHOF gradually increases; however, as the pH value of the solution continues to increase, the photocatalytic removal efficiency of U(VI) gradually decreases. This is mainly due to the interaction between U(VI) and photogenerated holes at low pH. h + In CdS 0.67 @Ni-pHOF catalyst surface competes for photogenerated electrons e ‒ At high pH, the hydrolysis of U(VI) interferes with the CdS 0.67 @Ni-pHOF catalyst utilizes visible light.

[0043] Figure 6 Under different initial U(VI) concentration conditions (C U(VI) =12.5, 25, 50, 100, 200, 400 mg / L, m / V=0.6 g / L, pH=5.0) CdS 0.67 @Ni-pHOF photocatalytic removal effect of U(VI). Figure 6 It can be seen that as the initial U(VI) concentration increases, CdS 0.67 The removal capacity of @Ni-pHOF for U(VI) gradually increased.

[0044] Figure 7 In the presence of different cations (Na + , K+ Mg 2+ , Ca 2+ 、Ce 3+ 、Sm 3+ 、Eu 3+ 、Gd 3+ , C cation =50 mg / L)CdS 0.67 @Ni-pHOF photocatalytic removal effect of U(VI). Figure 7 Compared with the control group (no cations), these cations have a significant effect on the CdS 0.67 The effect of Ni-pHOF on photocatalytic removal of U(VI) is almost negligible. 0.67 The selective removal rate of U(VI) by @Ni-pHOF catalyst is still as high as 94.89%, showing excellent selectivity.

[0045] Figure 8 In the presence of different anions (ClO4 ‒ 、Cl ‒ 、CO3 2‒ 、SO4 2‒ , C canion =50 mg / L)CdS 0.67 @Ni-pHOF photocatalytic removal effect of U(VI). Figure 8 It can be seen that compared with the control group (no anion), ClO4 ‒ 、Cl ‒ 、CO3 2‒ 、SO4 2‒ CdS 0.67 @Ni-pHOF has certain interference in the photocatalytic removal of U(VI).

[0046] Figure 9 CdS 0.67 @Ni-pHOF photocatalytic removal effect of U(VI) in multiple cycles; after 5 cycles, CdS 0.67 The photocatalytic removal rate of U(VI) by @Ni-pHOF catalyst can still reach 81.47%, showing excellent photostability, high reusability and good economic benefits.

[0047] To further evaluate the CdS 0.67 @Ni-pHOF has practical application potential in real uranium-containing radioactive wastewater. The CdS prepared in Example 1 0.67 The Ni-pHOF photocatalyst was used for the photocatalytic treatment of uranium-containing radioactive wastewater from a uranium mine in southwest China. The results showed that after 240 minutes of visible light irradiation, the U(VI) removal rate in the real uranium-containing radioactive wastewater could reach 95.9%, showing that the CdS0.67 @Ni-pHOF photocatalyst has excellent practical application potential.

[0048] The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any modification and replacement based on the technical solution and inventive concept provided by the present invention should be covered by the protection scope of the present invention.

Claims

1. Application of a nickel porphyrin-based hydrogen-bonded organic framework heterojunction material in the treatment of uranium-containing radioactive wastewater, characterized in that: A nickel-porphyrin-based hydrogen-bonded organic framework heterojunction material is added to uranium-containing radioactive wastewater to undergo a photocatalytic reaction under light irradiation, achieving photocatalytic reduction and removal of hexavalent uranium in the uranium-containing radioactive wastewater without the need for a hole trap in an air atmosphere. The method for preparing the nickel porphyrin-based hydrogen-bonded organic framework heterojunction material comprises the following steps: Step 1: preparing cadmium sulfide; Cadmium acetate dihydrate and thiourea in a mass ratio of 1:1-5 are ultrasonically dissolved in 30-80 parts by volume of deionized water for 10-60 minutes; the suspension is heated to 80-120°C for 6-10 hours; the suspension is cooled to room temperature, filtered, washed, and vacuum dried to obtain cadmium sulfide (CdS); Step 2: Preparation of nickel porphyrin-based hydrogen-bonded organic framework heterojunction materials; Take cadmium sulfide and 5,10,15,20-tetrakis(4-(2,4-diaminotriazine)phenyl)nickel porphyrin prepared in step 1 in different mass ratios, add them to 20-70 parts by volume of a mixed solvent, ultrasonicate for 10-30 minutes at room temperature, seal, heat to 100-180°C, heat for 60-90 hours; cool to room temperature, filter, wash, and vacuum dry to obtain nickel porphyrin-based hydrogen bonded organic framework heterojunction material CdS x @Ni-pHOF, the mass ratio x of cadmium sulfide and 5,10,15,20-tetrakis(4-(2,4-diaminotriazine)phenyl)nickelporphyrin is greater than 0 and less than or equal to 1; The mixed solvent is prepared by mixing o-dichlorobenzene, n-butanol and acetic acid in a volume ratio of 3:0.1-1.5:0.01-0.15, and the concentration of acetic acid is 4.5-7.5 mol / L.

2. The use of the nickel porphyrin-based hydrogen-bonded organic framework heterojunction material in the treatment of uranium-containing radioactive wastewater according to claim 1, characterized in that: The solid-liquid ratio of the nickel porphyrin-based hydrogen bond organic framework heterojunction material to uranium-containing radioactive wastewater is 0.6 g / L.

3. The use of the nickel porphyrin-based hydrogen-bonded organic framework heterojunction material in the treatment of uranium-containing radioactive wastewater according to claim 1, characterized in that: The pH of the uranium-containing radioactive wastewater is adjusted to 5.

4. The use of the nickel porphyrin-based hydrogen-bonded organic framework heterojunction material in the treatment of uranium-containing radioactive wastewater according to claim 1, characterized in that: The concentration of hexavalent uranium in the uranium-containing radioactive wastewater is adjusted to 50 mg / L.

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