Preparation method and application of ZnIn2S4 / polymer micelle nano composite photocatalyst

Abstract

The invention provides a preparation method and application of a ZnIn2S4 / polymer micelle nano composite photocatalyst, and belongs to the field of advanced material design and photocatalysis. According to the preparation method, a photo-induced polymerization induced self-assembly method is adopted, a polyacrylic acid macromolecular chain transfer agent and a styrene monomer are co-assembled with a ZnIn2S4 photocatalyst in the process of forming polymer micelles through in-situ polymerization under ultraviolet irradiation, and therefore the novel ZnIn2S4 / polymer micelle nano-composite photocatalyst is prepared. The preparation method disclosed by the invention is simple, and the compounding of ZnIn2S4 and the polymer micelle is realized in situ through a photo-induced polymerization induced self-assembly method. Besides, the inorganic / organic nano-composite photocatalyst prepared by the method has remarkable photocatalytic performance, can quickly degrade dye wastewater, and has a better application prospect in the technical field of environmental pollution treatment.

Description

Technical Field

[0001] This invention belongs to the field of composite photocatalyst materials and wastewater treatment technology, and specifically relates to a method for preparing and applying a ZnIn2S4 / polymer micelle nanocomposite photocatalyst. Background Technology

[0002] In the treatment of organic pollutants in water bodies, semiconductor photocatalysis technology has become an important direction due to its ability to drive degradation reactions using solar energy. Among them, the ternary sulfide ZnIn2S4 is an ideal candidate material for degrading water pollutants due to its visible light response characteristics (band gap ≈ 2.4 eV) and layered structure advantages. However, single ZnIn2S4 has the disadvantages of a carrier recombination rate exceeding 60% and a specific surface area typically <50 m². 2 Problems such as / g and activity decrease of more than 30% after four cycles are often addressed by methods such as ion doping, heterostructure construction, noble metal loading and polymer coating.

[0003] Inorganic / polymer composite nanoparticles represent an important new class of materials that leverage the complementary advantages of polymers and inorganic nanomaterials. In recent years, polymerization-induced self-assembly methods based on reversible addition-fragmentation chain transfer (RAFT) have attracted widespread attention for the in-situ high-concentration preparation of polymer micelle nanoparticles with different morphologies. For example, patent CN202310575937.0 describes the successful preparation of hydrophobic titanium dioxide / block copolymer composite nanoparticles by hybridizing poly(4-vinylpyridine) macromolecular chain transfer agent with styrene and metal-doped titanium dioxide during UV-initiated in-situ polymerization. Furthermore, polymerization of hydrophilic polyacrylic acid macromolecular chain transfer agent with inorganic ZnIn2S4 yields an organic / inorganic nanocomposite photocatalyst. Compared to a single inorganic ZnIn2S4 photocatalyst, the trithioester bond in the organic polyacrylic acid acts as a photoactive site, and the carboxyl group provides pollutant enrichment, thus achieving a synergistic "adsorption-catalysis" effect in the organic / inorganic hybrid structure, opening a new path for the development of efficient and stable water treatment technologies. Summary of the Invention

[0004] In view of this, the present invention aims to provide a method for preparing ZnIn2S4 / polymer micelle nanocomposite photocatalysts and their applications. To achieve the above-mentioned objective, the present invention provides the following technical solution:

[0005] A method for preparing a ZnIn2S4 / polymer micelle nanocomposite photocatalyst includes the following steps:

[0006] (1) Weigh acrylic acid, 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid and azobisisobutyronitrile, dissolve them in ethanol, heat in a water bath, and precipitate with diethyl ether after reaction to obtain a pale yellow viscous solid. Heat and dry to obtain polyacrylic acid macromolecular chain transfer agent.

[0007] (2) Weigh the self-made inorganic ZnIn2S4, polyacrylic acid macromolecular chain transfer agent, azobisisobutyronitrile and styrene, mix and disperse them in methanol solvent, and carry out polymerization reaction under ultraviolet light source; collect the precipitate at the bottom of the reaction liquid by centrifugation, wash it alternately with ethanol and water, and dry it by centrifugation to obtain ZnIn2S4 / polymer micelle nanocomposite photocatalyst.

[0008] The self-made ZnIn2S4 was prepared by a hydrothermal method, and the preparation steps are as follows:

[0009] Weigh 60 mg of Zn(NO3)2·6H2O, 120 mg of In(NO3)3 and 135 mg of thioacetamide, dissolve them in 80 mL of ethylene glycol / water (volume ratio 4:1), stir well, transfer to a reaction vessel, and react at 140 °C for 8 h. After cooling, collect the precipitate by centrifugation, wash it three times with ethanol and water alternately, and then dry it to obtain solid ZnIn2S4.

[0010] Preferably, in step 1, the molar ratio of acrylic acid, 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid and azobisisobutyronitrile is 1000-1500:5:1.

[0011] Preferably, in step 2, the molar ratio of the polyacrylic acid macromolecular chain transfer agent, styrene, and azobisisobutyronitrile is 2-10:4000-6500:1.

[0012] Preferably, in step 2, the mass ratio of the inorganic ZnIn2S4 to the polyacrylic acid macromolecular chain transfer agent is 2-8:1.

[0013] Preferably, in step 2, the intensity of the ultraviolet light source is 2-6 mW / cm². 2 The polymerization reaction time is 12–24 hours.

[0014] The present invention also provides a ZnIn2S4 / polymer micelle nanocomposite photocatalyst, which is obtained by the above preparation method.

[0015] This invention also provides an application of a ZnIn2S4 / polymer micelle nanocomposite photocatalyst in the photocatalytic reaction of dye wastewater. The specific steps are as follows: The prepared ZnIn2S4 / polymer micelle nanocomposite photocatalyst is added to a certain concentration of methylene blue aqueous solution and stirred for 2 hours in the dark for adsorption; a xenon lamp is used as the light source to carry out the photocatalytic reaction.

[0016] Furthermore, the concentration of the aqueous solution of methylene blue is 5-10 mg / L, and the amount of catalyst used is 0.5-1.5 mg / mL.

[0017] Furthermore, the luminous intensity of a xenon lamp is 80-500 mW / cm². 2 The photocatalytic degradation reaction time is 1-3 hours.

[0018] The beneficial effect achieved by this invention is the successful anchoring of polymer nanomicelles onto the surface of ZnIn2S4 under ultraviolet light irradiation, forming a novel organic / inorganic hybrid nanocomposite photocatalyst. The organic polymer nanomicelles contained in this nanocomposite catalyst not only serve as photocatalytic active sites but also possess pollutant enrichment functions; their hybridization with inorganic ZnIn2S4 achieves a synergistic "adsorption-catalysis" effect. Under visible light irradiation, this composite photocatalyst can effectively catalyze the degradation of methylene blue, demonstrating promising application prospects. Attached Figure Description

[0019] Figure 1 This is a SEM image of the inorganic ZnIn2S4 photocatalyst obtained in Example 1 of this invention;

[0020] Figure 2 This is a SEM image of the ZnIn2S4 / polymer micelle nanocomposite photocatalyst obtained in Example 1 of this invention;

[0021] Figure 3 This is a SEM image of the ZnIn2S4 / polymer micelle nanocomposite photocatalyst obtained in Example 2 of this invention;

[0022] Figure 4 This is a SEM image of the ZnIn2S4 / polymer micelle nanocomposite photocatalyst obtained in Example 3 of the present invention;

[0023] Figure 5 This is a SEM image of the organic polymer micelle photocatalyst obtained in Comparative Example 1 of this invention.

[0024] Figure 6 The image shows the UV-Vis spectrum of the photocatalytic degradation of methylene blue by the ZnIn2S4 / polymer micelle nanocomposite photocatalyst obtained in Example 1 of this invention.

[0025] Figure 7The image shows the UV-Vis spectrum of the photocatalytic degradation of methylene blue by the ZnIn2S4 / polymer micelle nanocomposite photocatalyst obtained in Example 2 of this invention.

[0026] Figure 8 The UV-Vis spectrum of the photocatalytic degradation of methylene blue by ZnIn2S4 obtained in Example 3 of this invention;

[0027] Figure 9 This is a comparison chart showing the reaction rates of methylene blue degradation in the ZnIn2S4 / polymer micelle nanocomposite photocatalyst in Example 1, the organic block copolymer photocatalyst in Comparative Example 1, and the inorganic ZnIn2S4 photocatalyst in Comparative Example 2 prepared according to the present invention. Detailed Implementation

[0028] The following detailed description of the preparation method of the ZnIn2S4 / polymer micelle nanocomposite photocatalyst provided by the present invention, with reference to the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0029] Example 1

[0030] Weigh 3.6g of acrylic acid, 72mg of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, and 6.4mg of azobisisobutyronitrile, dissolve them in 10mL of ethanol, heat in a water bath, and then precipitate with 100mL of diethyl ether to obtain a pale yellow viscous solid. Heat and dry to obtain a polyacrylic acid macromolecular chain transfer agent.

[0031] 10 mg ZnIn2S4, 40 mg polyacrylic acid macromolecular chain transfer agent, 0.2 mg azobisisobutyronitrile, 800 μL styrene, and 37.5 mL methanol were mixed and polymerized under ultraviolet light for 18 h. The reaction solution was centrifuged at 8000 rpm for 5 min, the precipitate was collected, and then washed twice with ethanol and water, followed by centrifugation, to obtain an organic / inorganic ZnIn2S4 / polymer micelle nanocomposite photocatalyst. Figure 1 This is a SEM image of the self-made ZnIn2S4 photocatalyst. Figure 3 The image shows a SEM image of the obtained ZnIn2S4 / polymer micelle nanocomposite photocatalyst. As can be seen from the image, a large number of spherical polymer micelles are composited on the surface of ZnIn2S4.

[0032] 5 mg of ZnIn2S4 / polymer micelle nanocomposite photocatalyst was added to 60 mL of methylene blue solution with a concentration of 5 mg / mL, and the mixture was stirred and adsorbed in the dark for 2 h. The mixture was then placed under a xenon lamp for photocatalytic reaction, and the reaction solution was collected every 10 min. After centrifugation, the absorbance was measured. Figure 6The UV-Vis absorption spectrum of the photocatalytic degradation of methylene blue by the obtained ZnIn2S4 / polymer micelle nanocomposite photocatalyst is shown. Its characteristic peak at 664 nm completely disappears after 60 min. Furthermore, the obtained first-order reaction kinetic curve is shown below. Figure 9 As shown in figure a, the reaction rate constant is 0.06 min. -1 This indicates that it has good photocatalytic performance.

[0033] Example 2

[0034] Weigh 3.6g of acrylic acid, 72mg of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, and 6.4mg of azobisisobutyronitrile, dissolve them in 10mL of ethanol, heat in a water bath, and after reaction, precipitate with 100mL of diethyl ether to obtain a pale yellow viscous solid. Dry the solid in a forced-air drying oven to obtain a polyacrylic acid macromolecular chain transfer agent.

[0035] 5 mg ZnIn2S4, 40 mg polyacrylic acid macromolecular chain transfer agent, 0.2 mg azobisisobutyronitrile, 37.5 mL methanol and 800 μL styrene were mixed and polymerized under ultraviolet light for 18 h. The reaction solution was centrifuged at 8000 rpm for 5 min, the precipitate was collected, and then washed with ethanol and water and centrifuged twice.

[0036] 5 mg of ZnIn2S4 / polymer micelle nanocomposite photocatalyst was added to 60 mL of methylene blue solution with a concentration of 5 mg / mL, and the mixture was stirred and adsorbed in the dark for 2 h. The mixture was then placed under a xenon lamp for photocatalytic reaction, and the reaction solution was collected every 10 min. After centrifugation, the absorbance was measured. Figure 7 The UV-Vis absorption spectrum of the obtained ZnIn2S4 / polymer micelle nanocomposite photocatalyst for the photocatalytic degradation of methylene blue shows a characteristic peak at 664 nm that almost completely disappeared after 120 min.

[0037] Example 3

[0038] Weigh 3.6g of acrylic acid, 72mg of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, and 6.4mg of azobisisobutyronitrile, dissolve them in 10mL of ethanol, heat in a water bath, and after reaction, precipitate with 100mL of diethyl ether to obtain a pale yellow viscous solid. Dry the solid in a forced-air drying oven to obtain a polyacrylic acid macromolecular chain transfer agent.

[0039] 10 mg ZnIn2S4, 80 mg polyacrylic acid macromolecular chain transfer agent, 0.2 mg azobisisobutyronitrile, 37.5 mL methanol and 800 μL styrene were mixed and polymerized under ultraviolet light for 18 h. The reaction solution was centrifuged at 8000 rpm for 5 min, the precipitate was collected, and then washed with ethanol and water and centrifuged twice.

[0040] 5 mg of ZnIn2S4 / polymer micelle nanocomposite photocatalyst was added to 60 mL of methylene blue solution with a concentration of 5 mg / mL, and the mixture was stirred and adsorbed in the dark for 2 h. The mixture was then placed under a xenon lamp for photocatalytic reaction, and the reaction solution was collected every 10 min. After centrifugation, the absorbance was measured. Figure 8 The UV-Vis absorption spectrum of the obtained ZnIn2S4 / polymer micelle nanocomposite photocatalyst for the photocatalytic degradation of methylene blue shows a characteristic peak at 664 nm that almost completely disappeared after 120 min.

[0041] Comparative Example 1

[0042] 40 mg of polyacrylic acid macromolecular chain transfer agent, 2 mg of azobisisobutyronitrile, and 800 μL of styrene were dissolved in 37.5 mL of methanol, and the polymerization reaction was carried out under ultraviolet light for 18 h. After the reaction was completed, the reaction solution was centrifuged at 8000 rpm for 5 min, the precipitate was collected, and then washed with ethanol and water successively and centrifuged twice to obtain the organic polymer micelle photocatalyst. Figure 5 The image shows a SEM image of the obtained polymer micelle photocatalyst, which shows the formation of polymer micelles.

[0043] 5 mg of polymeric micelle photocatalyst was added to 60 mL of a 5 mg / mL methylene blue solution for adsorption for 2 h. The mixed solution was then irradiated under a xenon lamp, and the photocatalytic reaction solution was collected every 10 min. After centrifugation, its absorbance was measured. The resulting first-order reaction kinetic curve is shown below. Figure 9 As shown in b, its reaction rate constant is 0.03 min. -1 .

[0044] Comparative Example 2

[0045] 5 mg of ZnIn2S4 photocatalyst was added to 50 mL of a 5 mg / mL methylene blue solution, and the mixture was stirred and adsorbed in the dark for 2 h. The mixture was then placed under a xenon lamp, and the reaction solution was collected every 10 min. After centrifugation, the absorbance was measured. The resulting first-order reaction kinetic curve is shown below. Figure 9 As shown in c, its reaction rate constant is 0.02 min. -1 .

[0046] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a ZnIn2S4 / polymer micellar nanocomposite photocatalyst, comprising the following steps: (1) weighing acrylic acid, 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid and azobisisobutyronitrile, dissolving them in ethanol, heating the reaction in a water bath for a period of time, precipitating with diethyl ether to obtain a light yellow viscous precipitate; and drying to obtain a polyacrylic acid macromolecular chain transfer agent; (2) weighing self-prepared inorganic ZnIn2S4, polyacrylic acid macromolecular chain transfer agent, azobisisobutyronitrile and styrene, dissolving and mixing them in a methanol solvent, and performing a polymerization reaction under a UV light source; collecting the precipitate at the bottom of the reaction liquid by centrifugation, washing it with ethanol and water alternately, and drying it by centrifugation to obtain a ZnIn2S4 / polymer micellar nanocomposite photocatalyst.

2. The production method according to claim 1, characterized by, In step 1, the molar ratio of the acrylic acid, 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid and azobisisobutyronitrile is 1000-1500:5:

1.

3. The preparation method according to claim 1, characterized in that, In step 2, the molar ratio of the polyacrylic acid macromolecular chain transfer agent, styrene and azobisisobutyronitrile is 2-10:4000-6500:

1.

4. The method of claim 1, wherein, In step 2, the mass ratio of the inorganic ZnIn2S4 and the polyacrylic acid macromolecular chain transfer agent is 2-8:

1.

5. The preparation method according to claim 1, characterized in that, In step 2, the intensity of the UV light source is 2-6 mW / cm 2 ; the polymerization reaction time is 12-24 h.

6. A ZnIn2S4 / polymer micellar nanocomposite photocatalyst, characterized in that, The ZnIn2S4 / polymer micellar nanocomposite photocatalyst obtained by the method of any one of claims 1-5.

7. Use of ZnIn2S4 / polymer micellar nanocomposite photocatalyst, characterized in that, The ZnIn2S4 / polymer micellar nanocomposite photocatalyst is applied to a photocatalytic reaction in dye wastewater.

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