Photocatalyst, preparation method thereof and application of photocatalyst in coal mine water treatment

Abstract

The invention discloses a photocatalyst as well as a preparation method and application thereof in coal mine water treatment, and belongs to the technical field of photocatalysis. According to the photocatalyst, indium zinc sulfide with a unique nanoflower structure is used as a substrate, and silver-nickel alloy nanoparticles with good conductivity are loaded on the surface of the substrate; an efficient synergistic effect is formed between the silver-nickel alloy nanoparticles and the indium zinc sulfide nanoflowers. On one hand, the structure advantage of the nanoflower morphology on indium zinc sulfide and the property of the bimetallic silver-nickel alloy are combined, and the widened light absorption range is obtained; on the other hand, after the cocatalyst is introduced, carrier separation and transportation are facilitated by means of excellent conductivity of the bimetallic silver-nickel alloy, and the photocatalytic performance of the indium zinc sulfide nanoflower is enhanced. When being used for treating coal mine wastewater, the coal mine wastewater treatment agent shows the beneficial effect of synergistic interaction, specifically, the coal mine wastewater treatment agent has the efficient and synchronous removal capacity on typical heavy metal pollutants and organic pollutants, and the technical effect is obviously superior to that of a single component or the prior art.

Description

Technical Field

[0001] This invention belongs to the field of photocatalysis technology, specifically relating to a photocatalyst, its preparation method, and its application in coal mine water treatment. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Coal mine wastewater is highly toxic wastewater generated during the mining process. Its composition is complex, containing both recalcitrant organic pollutants (such as oils, dyes, and phenols) and a variety of heavy metal ions (such as chromium, arsenic, lead, copper, and zinc). When these pollutants coexist, they easily form compound pollution, exacerbating environmental risks. Traditional treatment methods (such as coagulation sedimentation and biological treatment) can partially remove pollutants, but they suffer from problems such as incomplete degradation of organic pollutants, difficulty in achieving deep purification of heavy metal ions, and insufficient capacity for synergistic treatment of multiple pollutants. Photocatalysis, as a green advanced oxidation strategy, shows potential in wastewater treatment. Its core lies in generating active free radicals (such as ·OH and ·SO4) through photogenerated electron-hole pairs. - Photocatalysis enables the oxidative decomposition or reduction fixation of pollutants. While current photocatalysis technology has made progress in the treatment of single pollutants, it still faces two major bottlenecks in the synergistic purification of multiple pollutants in mine wastewater: first, existing catalysts lack the activity to simultaneously act on organic pollutants and heavy metal ions; second, material design has not been optimized for the complex composition of mine wastewater (such as the coexistence of multiple ions).

[0004] Zinc indium sulfide (ZnIn2S4), a visible-light-responsive semiconductor material, has become a hot topic in photocatalysis research due to its suitable band gap (approximately 2.0-2.8 eV) and unique nanoflower-like structure, resulting in high specific surface area and abundant active sites. In recent years, modifications such as elemental doping, heterostructure building, and vacancy engineering have significantly improved the separation efficiency of photogenerated carriers. For example, loading silver or nickel onto the surface of ZnIn2S4 can enhance light absorption or hydrogen production performance, but its application is limited to the degradation of organic pollutants, not involving complex mine wastewater systems, and there are no reports of simultaneous removal of heavy metal ions. In particular, mine wastewater requires catalysts with both oxidizing (degrading organic matter) and reducing (immobilizing heavy metals) properties, which existing ZnIn2S4-based materials are insufficiently suited for. Although some studies (such as α-Fe2O3 for arsenic removal) show that photocatalysts can reduce and immobilize heavy metals, multifunctional materials capable of simultaneously mineralizing organic matter and adsorbing heavy metals remain scarce. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a photocatalyst, its preparation method, and its application in coal mine water treatment. The photocatalyst provided by the present invention can achieve excellent ultraviolet and visible light photocatalytic treatment effects on coal mine water, and is a highly efficient photocatalyst.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a photocatalyst comprising indium zinc sulfide nanoflowers and silver-nickel alloy nanoparticles supported on the surface of the indium zinc sulfide nanoflowers.

[0007] In some embodiments of the present invention, the molar ratio of silver to nickel in the silver-nickel alloy nanoparticles is (1~100):(1~100), preferably (25~75):(25~75), and more preferably 75:25.

[0008] In some embodiments of the present invention, the silver-nickel alloy nanoparticles are 1% to 5% of the mass of indium zinc sulfide nanoflowers, preferably 1% to 3%, and more preferably 2%.

[0009] In some embodiments of the present invention, the diameter of the indium zinc sulfide nanoflowers is 5~7 μm.

[0010] In some embodiments of the present invention, the particle size of the silver-nickel alloy nanoparticles is ...

[0011] A second aspect of the present invention provides a method for preparing the photocatalyst described in the first aspect, comprising: Indium zinc sulfide nanoflowers, silver salt solution, nickel salt solution and water are mixed and dissolved to obtain a mixed solution; Sodium borohydride was added to the mixture, stirred, and after the reaction, the mixture was washed, dried, and ground to obtain the photocatalyst.

[0012] In some embodiments of the present invention, the preparation method of indium zinc sulfide nanoflowers includes: Zinc salt, indium salt, thioacetamide and water were mixed, stirred and then subjected to a hydrothermal reaction. After the reaction, the mixture was cooled to room temperature, dried and ground to obtain indium zinc sulfide nanoflowers.

[0013] In some embodiments of the present invention, the temperature of the hydrothermal reaction is 150~170℃, the time is 10~14 h, and the heating rate is 1.3~3℃ / min.

[0014] In some embodiments of the present invention, the silver salt includes any one or more of silver nitrate, silver fluoride, and silver perchlorate, preferably silver nitrate.

[0015] In some embodiments of the present invention, the nickel salt includes any one or more of nickel sulfate, nickel chloride, and nickel nitrate, preferably nickel nitrate.

[0016] In some embodiments of the present invention, the concentration of the silver salt solution is 0.05~0.15 M, the concentration of the nickel salt solution is 0.05~0.15 M, and the ratio of the indium zinc sulfide nanoflowers, silver salt solution, nickel salt solution and water is (1.32~4.04 g):(0.01~3.71 mL):(0.01~6.82 mL):(500-700 mL).

[0017] In some embodiments of the present invention, sodium borohydride solution is added to the mixture and stirred for 0.5 to 3 hours.

[0018] In some embodiments of the present invention, the concentration of the sodium borohydride solution is 0.4~0.6 M, and the amount used is 4~6 mL.

[0019] A third aspect of the present invention provides the application of the photocatalyst described in the first aspect or the photocatalyst prepared by the preparation method described in the second aspect in water treatment.

[0020] In some embodiments of the present invention, the water includes coal mine water.

[0021] A fourth aspect of the present invention provides a method for water treatment, comprising: adding the photocatalyst described in the first aspect or the photocatalyst prepared by the preparation method described in the second aspect to the water to be treated, and irradiating it with light.

[0022] In some embodiments of the present invention, the aqueous solution containing the photocatalyst is stirred in the dark until adsorption-desorption equilibrium is reached before light exposure.

[0023] In some embodiments of the present invention, the concentration of the photocatalyst in the water to be treated is 0.5~1.5 mg / mL.

[0024] The beneficial effects of this invention are as follows: This invention provides a photocatalyst that exhibits a synergistic effect in treating coal mine wastewater, specifically demonstrating highly efficient simultaneous removal of typical heavy metal pollutants (such as chromium ions) and organic pollutants (such as phenol). Its technical performance is significantly superior to single-component or existing technologies. The photocatalyst provided by this invention uses indium zinc sulfide with a unique nanoflower structure as its matrix. Its unique open structure assembled from two-dimensional nanosheets provides a large specific surface area, which is beneficial for pollutant adsorption and photocatalytic reactions. Its surface is loaded with highly conductive co-catalyst—silver-nickel alloy nanoparticles. A highly efficient synergistic effect is formed between the co-catalyst and indium zinc sulfide: on the one hand, combining the structural advantages of the nanoflower morphology of indium zinc sulfide with the properties of the bimetallic silver-nickel alloy, a broadened light absorption range is obtained; on the other hand, the excellent conductivity of the bimetallic silver-nickel alloy facilitates carrier separation and transport after the introduction of the co-catalyst, enhancing the photocatalytic performance of the indium zinc sulfide nanoflowers.

[0025] The photocatalyst of this invention not only significantly improves the simultaneous removal efficiency of typical heavy metals and organic pollutants in mine wastewater, but its stable structure and performance also provide a new technical solution for addressing the challenge of deep purification of complex wastewater components. Specifically, the silver component, due to its excellent conductivity, can effectively capture photogenerated electrons, suppress electron-hole recombination, and directionally transfer electrons to reduce high-valence heavy metal ions to low-toxicity heavy metal ions. The nickel component optimizes hole migration and enhances oxidation capacity, thereby driving holes or generated reactive oxygen species (such as ·OH) to completely oxidize and degrade organic pollutants such as phenol. This improved electron-hole separation efficiency is key to the enhanced photocatalytic performance. Especially in complex systems like mine wastewater where multiple pollutants coexist, the silver-nickel alloy loading enables the catalyst to simultaneously and efficiently carry out reduction and oxidation reactions, solving the problem that single-function catalysts cannot cope with complex pollution. Secondly, the stable framework structure of the indium zinc sulfide nanoflowers provides a strong anchoring point for the silver-nickel alloy nanoparticles, effectively preventing the nanoparticles from detaching and agglomerating during the catalytic process, which is beneficial for catalyst recovery and recycling.

[0026] This invention prepares a bimetallic silver-nickel alloy indium zinc sulfide composite photocatalyst via a solvothermal method. The synthesis process and equipment are simple, the operation is straightforward, the production cost is low, the efficiency is high, the repeatability is good, and the industrial application prospects are promising. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0028] Figure 1 This is a scanning electron microscope image of the photocatalyst prepared in Example 3 of the present invention.

[0029] Figure 2 This is a transmission electron microscope image of the photocatalyst prepared in Example 3 of the present invention.

[0030] Figure 3 This is a high-magnification transmission electron microscope image of the photocatalyst prepared in Example 3 of the present invention.

[0031] Figure 4 This is a comparison chart of the ultraviolet-visible light absorption intensity of the photocatalysts prepared in Example 3, Comparative Example 1, Comparative Example 2 and Comparative Example 3 of the present invention.

[0032] Figure 5 The graph shows the photocatalysts prepared in Examples 1-5 and Comparative Examples 1-3 of this invention, under ultraviolet and visible light irradiation, to treat heavy metal ions (a) and organic pollutants (b) in coal mine water after filtering coal slag. Detailed Implementation

[0033] In view of the lack of a multifunctional photocatalyst that can simultaneously and efficiently degrade organic pollutants and remove heavy metal ions in mine wastewater to solve the problems of poor adaptability and low synergistic purification efficiency of existing technologies for complex wastewater components, this invention proposes a photocatalyst, its preparation method, and its application in coal mine water treatment.

[0034] A first typical embodiment of the present invention provides a photocatalyst comprising indium zinc sulfide nanoflowers and silver-nickel alloy nanoparticles supported on the surface of the indium zinc sulfide nanoflowers.

[0035] The photocatalyst provided by this invention consists of indium zinc sulfide nanoflowers and bimetallic silver-nickel alloy nanoparticles supported on their surface. Indium zinc sulfide, which has a unique nanoflower structure, serves as the matrix, while the surface is supported with a bimetallic silver-nickel alloy cocatalyst with good conductivity. On the one hand, it combines the structural advantages of the nanoflower morphology of indium zinc sulfide with the properties of the bimetallic silver-nickel alloy, thereby achieving a broadened light absorption range. On the other hand, the introduction of the cocatalyst, with the help of the excellent conductivity of the bimetallic silver-nickel alloy, facilitates carrier separation and transport, enhancing the photocatalytic performance of the indium zinc sulfide nanoflowers.

[0036] The photocatalyst provided by this invention, compared with pure indium zinc sulfide nanoflowers, broadens the light absorption range and improves light collection efficiency through the presence of a bimetallic silver-nickel alloy via plasma effects and bandgap modulation; it can also act as an electron sink to promote space charge separation and suppress the rapid recombination of photogenerated charges. Simultaneously, this photocatalyst exhibits enhanced performance in ultraviolet and visible light photocatalytic treatment of coal mine water.

[0037] In this invention, the molar ratio of silver to nickel in the silver-nickel alloy nanoparticles is (1~100):(1~100), specifically 1:99, 25:75, 50:50, 75:25, 99:1, etc., preferably (25~75):(25~75), and more preferably 75:25, at which point the photocatalyst performance reaches its optimal level.

[0038] In this invention, the silver-nickel alloy nanoparticles are 1% to 5% of the mass of indium zinc sulfide nanoflowers, preferably 1% to 3%, specifically 1%, 2%, 3%, etc., and more preferably 2%, at which point the photocatalyst performance reaches its optimal level.

[0039] In this invention, the diameter of the indium zinc sulfide nanoflowers is 5~7 μm.

[0040] In this invention, the particle size of the silver-nickel alloy nanoparticles is 4~6 nm.

[0041] The photocatalyst provided by this invention has a narrower band gap, a wider light absorption range, faster photogenerated carrier separation and transfer efficiency, and high efficiency in photocatalysis with ultraviolet and visible light photocatalytic effects.

[0042] A second typical embodiment of the present invention provides a method for preparing the aforementioned photocatalyst, comprising: Indium zinc sulfide nanoflowers, silver salt solution, nickel salt solution and water are mixed and dissolved to obtain a mixed solution; Sodium borohydride was added to the mixture, stirred, and after the reaction, the mixture was washed, dried, and ground to obtain the photocatalyst.

[0043] This invention prepares a photocatalyst via a solvothermal method. The synthesis process and equipment are simple, the operation is straightforward, the production cost is low, the efficiency is high, the reproducibility is good, and the industrial application prospects are promising. The prepared photocatalyst can achieve ultraviolet and visible light photocatalytic treatment of coal mine water, and is a highly efficient and stable photocatalyst.

[0044] The present invention does not require that the source of indium zinc sulfide nanoflowers be specified. They can be commercially available indium zinc sulfide nanoflowers purchased directly, or indium zinc sulfide nanoflowers prepared according to existing preparation methods.

[0045] In this invention, the preparation method of indium zinc sulfide nanoflowers includes: Zinc salt, indium salt, thioacetamide and water were mixed, stirred and then subjected to a hydrothermal reaction. After the reaction, the mixture was cooled to room temperature, dried and ground to obtain indium zinc sulfide nanoflowers.

[0046] The zinc salts include, but are not limited to, any one or more of zinc sulfate, zinc chloride, zinc nitrate, and zinc acetate. The indium salts include, but are not limited to, any one or more of indium trichloride, indium(III) bromide or indium triiodide, indium(III) trifluoride, bis(trifluoromethylsulfonamide)indium(III), and indium(III) acetate.

[0047] In this invention, the method for preparing indium zinc sulfide nanoflowers includes: Zinc sulfate heptahydrate, indium trichloride tetrahydrate, and thioacetamide were added to deionized water and stirred until homogeneous for hydrothermal reaction. After the reaction was complete, the mixture was cooled to room temperature, dried, and ground to obtain indium zinc sulfide nanoflowers.

[0048] In this invention, the amount of zinc sulfate heptahydrate is 7.93-9.33 g, preferably 8.63 g; the amount of indium trichloride tetrahydrate is 5.16-6.56 g, preferably 5.86 g; the amount of thioacetamide is 8.22-9.72 g, preferably 9.02 g; the amount of deionized water is 600-800 mL, preferably 700 mL; and the hydrothermal reaction vessel is a 1000 mL reaction vessel.

[0049] In this invention, the temperature of the hydrothermal reaction is 150~170℃, preferably 160℃, the time is 10~14 h, preferably 12 h, and the heating rate is 1.3~3℃ / min, preferably 2℃ / min.

[0050] The temperature and holding time of the hydrothermal reaction process have a significant impact on obtaining high-performance indium zinc sulfide nanoflower materials. If the hydrothermal temperature is too low, the precursor reaction kinetics are insufficient, making it difficult to form a typical flower-like hierarchical structure. If the hydrothermal temperature is too high, the nanosheets may overgrow or accumulate, and the indium zinc sulfide nanoflowers will decompose. Only when the hydrothermal temperature is 160℃ can the indium zinc sulfide nanosheets undergo a self-assembly process, orientedly curl, and construct nanoflowers with a three-dimensional structure.

[0051] In this invention, the silver salt includes, but is not limited to, any one or more of silver nitrate, silver fluoride, and silver perchlorate, preferably silver nitrate.

[0052] In this invention, the nickel salt includes, but is not limited to, any one or more of nickel sulfate, nickel chloride, and nickel nitrate, preferably nickel nitrate.

[0053] In this invention, the concentration of the silver salt solution is 0.05~0.15 M, preferably 0.1 M, and the concentration of the nickel salt solution is 0.05~0.15 M, preferably 0.1 M. The amount of the silver salt solution used is 0-3.71 mL; the amount of the nickel salt solution used is 6.82-0 mL; and the amount of water used is 500-700 mL, preferably 600 mL.

[0054] In this invention, the ratio of the indium zinc sulfide nanoflowers, silver salt solution, nickel salt solution and water is (1.32~4.04 g):(0.01~3.71 mL):(0.01~6.82 mL):(500-700 mL), preferably 2 g:(0.01~3.71 mL):(0.01~6.82 mL):600 mL.

[0055] In this invention, sodium borohydride solution is added to the mixture and stirred for 0.5 to 3 hours, preferably 1 hour.

[0056] Understandably, sufficient stirring time is beneficial for the complete reduction of precursor ions and the formation of uniformly sized bimetallic silver-nickel alloy nanoparticles. However, exceeding 1 hour does not further promote the regulation of alloy composition and may cause the formed nanoparticles to detach from the indium zinc sulfide substrate, resulting in additional time costs. When the time is less than 1 hour, the reduction of silver-nickel ions is incomplete, and the alloy nanoparticles are small in size, have poor crystallinity, and are unevenly distributed, making it difficult to form a tight heterojunction interface with the indium zinc sulfide substrate, thus affecting the effective extraction and transport of photogenerated electrons.

[0057] In this invention, the concentration of the sodium borohydride solution is 0.4~0.6 M, preferably 0.5 M, and the amount used is 4~6 mL, preferably 5 mL.

[0058] A third typical embodiment of the present invention provides an application of the aforementioned photocatalyst in water treatment.

[0059] In this invention, the water includes coal mine water, and the water treatment is photocatalytic treatment of the coal mine water.

[0060] A fourth typical embodiment of the present invention provides a water treatment method, comprising: adding the photocatalyst to the water to be treated and irradiating it with light.

[0061] In this invention, the aqueous solution containing the photocatalyst is stirred in the dark until adsorption-desorption equilibrium is reached before light exposure.

[0062] In this invention, the concentration of the photocatalyst in the water to be treated is 0.5~1.5 mg / mL.

[0063] In this invention, a photocatalyst is used for photocatalytic treatment of coal mine water, which differs from electrocatalytic treatment. Photocatalytic treatment of coal mine water involves electrons in the valence band of the catalyst material being excited by photons to jump to the conduction band, and then migrating to the material surface to directly reduce heavy metal ions (such as Cr(VI)) in the water or oxidize organic pollutants (such as phenols) using holes. The driving force for this process is solar energy. In contrast, electrocatalytic treatment of coal mine water involves applying a potential through an external circuit to drive electrons to migrate directionally to the catalyst surface. The catalyst lowers the activation energy of the reaction, thereby enhancing the adsorption, reduction / oxidation, and desorption processes of heavy metal ions and organic pollutants on the electrode surface. The driving force for this process is external electrical energy. Therefore, the mechanisms by which catalysts enhance the treatment performance of coal mine water in photocatalysis and electrocatalysis are different and irrelevant.

[0064] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0065] The indium zinc sulfide nanoflowers used in the following examples and comparative examples were all prepared by the following method: 8.63 g zinc sulfate heptahydrate, 5.86 g indium trichloride tetrahydrate, and 9.02 g thioacetamide were added to 700 mL of deionized water and stirred until fully dissolved to prepare a mixture. The mixture was then transferred to a 1000 mL hydrothermal reactor and kept at 160 °C for 12 h. After the reaction was complete, the mixture was cooled to room temperature, vacuum dried, and then ground to obtain indium zinc sulfide nanoflowers.

[0066] Example 1 This embodiment provides a photocatalyst that uses indium zinc sulfide nanoflowers as a carrier, on which bimetallic silver-nickel alloy nanoparticles are loaded. The molar ratio of silver to nickel in the bimetallic silver-nickel alloy nanoparticles is 25:75. The loading amount of the bimetallic silver-nickel alloy nanoparticles is 2% of the mass of the indium zinc sulfide nanoflowers.

[0067] The method for preparing the photocatalyst provided in this embodiment is as follows: 1.41 mL of 0.1 M silver nitrate solution, 4.23 mL of 0.1 M nickel nitrate solution, and 2 g of indium zinc sulfide nanoflower powder were added to 600 mL of deionized water, stirred, and fully dissolved to prepare the first mixture.

[0068] Add 5 mL of 0.5 M sodium borohydride solution to the first mixture, stir for 1 hour, and mix thoroughly to prepare the second mixture. Wash, vacuum dry, and grind the third mixture to obtain a bimetallic silver-nickel alloy indium zinc sulfide composite photocatalyst.

[0069] In this embodiment, the photocatalyst was prepared by growing bimetallic silver-nickel alloy nanoparticles on the surface of indium zinc sulfide nanoflowers. Compared with the single-structure indium zinc sulfide nanoflowers, the excellent electrical conductivity of the bimetallic silver-nickel alloy nanoparticles promotes the separation of photogenerated electrons and holes in the indium zinc sulfide nanoflowers, which is beneficial to the transport of charge carriers and enhances the photocatalytic performance of the photocatalyst. Figure 5 As shown, compared with Comparative Examples 1 and 2, the bimetallic silver-nickel alloy indium zinc sulfide composite photocatalyst also exhibits enhanced photocatalytic activity in treating heavy metal ions and organic pollutants in coal mine water after filtering coal slag under ultraviolet and visible light.

[0070] Example 2 This embodiment provides a photocatalyst that uses indium zinc sulfide nanoflowers as a carrier, on which bimetallic silver-nickel alloy nanoparticles are loaded. The molar ratio of silver to nickel in the bimetallic silver-nickel alloy nanoparticles is 50:50. The loading amount of the bimetallic silver-nickel alloy nanoparticles is 2% of the mass of the indium zinc sulfide nanoflowers.

[0071] The method for preparing the photocatalyst provided in this embodiment is as follows: Add 2.4 mL of 0.1 M silver nitrate solution, 2.4 mL of 0.1 M nickel nitrate solution, and 2 g of indium zinc sulfide nanoflower powder to 600 mL of deionized water, stir and dissolve thoroughly to prepare the first mixture.

[0072] Add 5 mL of 0.5 M sodium borohydride solution to the first mixture, stir for 1 hour, and mix thoroughly to prepare the second mixture. Wash, vacuum dry, and grind the second mixture to obtain the photocatalyst.

[0073] In this embodiment, the photocatalyst was prepared by growing bimetallic silver-nickel alloy nanoparticles on the surface of indium zinc sulfide nanoflowers. Compared with the single-structure indium zinc sulfide nanoflowers, the excellent electrical conductivity of the bimetallic silver-nickel alloy nanoparticles promoted the separation of photogenerated electrons and holes in the indium zinc sulfide nanoflowers, which is beneficial to the transport of charge carriers and enhances the photocatalytic performance of the photocatalyst. Compared with Example 1, Comparative Example 1, and Comparative Example 2, this photocatalyst also showed enhanced photocatalytic activity in treating heavy metal ions and organic pollutants (such as coal slag) in coal mine water after filtration under ultraviolet and visible light. Figure 5 ).

[0074] Example 3 This embodiment provides a photocatalyst that uses indium zinc sulfide nanoflowers as a carrier, on which bimetallic silver-nickel alloy nanoparticles are loaded. The molar ratio of silver to nickel in the bimetallic silver-nickel alloy nanoparticles is 75:25. The loading amount of the bimetallic silver-nickel alloy nanoparticles is 2% of the mass of the indium zinc sulfide nanoflowers.

[0075] The method for preparing the photocatalyst provided in this embodiment is as follows: Add 3.14 mL of 0.1 M silver nitrate solution, 1.06 mL of 0.1 M nickel nitrate solution, and 2 g of indium zinc sulfide nanoflower powder to 600 mL of deionized water, stir and dissolve thoroughly to prepare the first mixture.

[0076] Add 5 mL of 0.5 M sodium borohydride solution to the first mixture, stir for 1 hour, and mix thoroughly to prepare the second mixture. Wash, vacuum dry, and grind the second mixture to obtain the photocatalyst.

[0077] like Figure 1 , Figure 2 and Figure 3 As shown, the photocatalyst prepared in this embodiment consists of bimetallic silver-nickel alloy nanoparticles grown on the surface of indium zinc sulfide nanoflowers.

[0078] Figure 3 High-magnification transmission electron microscopy (TEM) images revealed clear lattice fringes on the surface of the indium zinc sulfide nanoflowers, corresponding to their (102) crystal plane (d=0.317 nm). Simultaneously, a composite structure of silver and nickel was attached to the surface of the indium zinc sulfide nanoflowers, corresponding to the silver (111) crystal plane (d=0.238 nm) and the nickel (111) crystal plane (d=0.222 nm), respectively. The systematic shift in the interplanar spacing between these two structures compared to the standard values ​​for pure silver and pure nickel indicates the formation of lattice interactions between silver and nickel atoms, confirming the successful loading of silver-nickel alloy nanoparticles onto the surface of indium zinc sulfide (coexisting in an alloy form, rather than a simple physical mixture).

[0079] UV-Vis spectrophotometry demonstrated that, compared to single-structure indium zinc sulfide nanoflowers, the presence of a small amount of bimetallic silver-nickel alloy nanoparticles enhanced the light absorption capacity of the photocatalyst, broadened the visible light absorption limit, and improved the utilization rate of sunlight (e.g., ...). Figure 4 Meanwhile, due to the excellent electrical conductivity of the bimetallic silver-nickel alloy nanoparticles, the separation of photogenerated electrons and holes in the indium zinc sulfide nanoflowers is promoted, which is beneficial to the transport of charge carriers and enhances the photocatalytic performance of the photocatalyst. Compared with Examples 1, 2, Comparative Examples 1 and 2, this photocatalyst also showed optimized photocatalytic activity in treating heavy metal ions and organic pollutants (such as coal slag) after filtering coal slag from coal mine water under ultraviolet and visible light. Figure 5 ).

[0080] Example 4 This embodiment provides a photocatalyst that uses indium zinc sulfide nanoflowers as a carrier, on which bimetallic silver-nickel alloy nanoparticles are loaded. The molar ratio of silver to nickel in the bimetallic silver-nickel alloy nanoparticles is 75:25. The loading amount of the bimetallic silver-nickel alloy nanoparticles is 1% of the mass of the indium zinc sulfide nanoflowers.

[0081] The method for preparing the photocatalyst provided in this embodiment is as follows: 3.14 mL of 0.1 M silver nitrate solution, 1.06 mL of 0.1 M nickel nitrate solution, and 4.04 g of indium zinc sulfide nanoflower powder were added to 600 mL of deionized water, stirred, and fully dissolved to prepare the first mixture.

[0082] Add 5 mL of 0.5 M sodium borohydride solution to the first mixture, stir for 1 hour, and mix thoroughly to prepare the second mixture. Wash, vacuum dry, and grind the second mixture to obtain the photocatalyst.

[0083] The photocatalyst prepared in this embodiment consists of bimetallic silver-nickel alloy nanoparticles grown on the surface of indium zinc sulfide nanoflowers. Compared with single-structure indium zinc sulfide nanoflowers, the excellent electrical conductivity of the bimetallic silver-nickel alloy nanoparticles promotes the separation of photogenerated electrons and holes in the indium zinc sulfide nanoflowers, which is beneficial for carrier transport and enhances the photocatalytic performance of the photocatalyst. Compared with Examples 1, 2, 3, Comparative Examples 1, 2, and 3, this photocatalyst also shows enhanced photocatalytic activity in treating heavy metal ions and organic pollutants (such as coal slag) in coal mine water after filtration under ultraviolet and visible light. Figure 5 ).

[0084] Example 5 This embodiment provides a photocatalyst that uses indium zinc sulfide nanoflowers as a carrier, on which bimetallic silver-nickel alloy nanoparticles are loaded. The molar ratio of silver to nickel in the bimetallic silver-nickel alloy nanoparticles is 75:25. The loading amount of the bimetallic silver-nickel alloy nanoparticles is 3% of the mass of the indium zinc sulfide nanoflowers.

[0085] The method for preparing the photocatalyst provided in this embodiment is as follows: Add 3.14 mL of 0.1 M silver nitrate solution, 1.06 mL of 0.1 M nickel nitrate solution, and 1.32 g of indium zinc sulfide nanoflower powder to 600 mL of deionized water, stir and dissolve thoroughly to prepare the first mixture.

[0086] Add 5 mL of 0.5 M sodium borohydride solution to the first mixture, stir for 1 hour, and mix thoroughly to prepare the second mixture. Wash, vacuum dry, and grind the second mixture to obtain the photocatalyst.

[0087] The photocatalyst prepared in this embodiment consists of bimetallic silver-nickel alloy nanoparticles grown on the surface of indium zinc sulfide nanoflowers. Compared with single-structure indium zinc sulfide nanoflowers, the excellent electrical conductivity of the bimetallic silver-nickel alloy nanoparticles promotes the separation of photogenerated electrons and holes in the indium zinc sulfide nanoflowers, which is beneficial for carrier transport and enhances the photocatalytic performance of the photocatalyst. Compared with Examples 1, 2, 3, 4, Comparative Examples 1, 2, and 3, this photocatalyst also shows enhanced photocatalytic activity in treating heavy metal ions and organic pollutants (such as coal slag) in coal mine water filtered under ultraviolet and visible light. Figure 5 ).

[0088] Comparative Example 1 An indium zinc sulfide nanoflower photocatalyst, the preparation method of which is as follows: 8.63 g zinc sulfate heptahydrate, 5.86 g indium trichloride tetrahydrate, and 9.02 g thioacetamide were added to 700 mL of deionized water and stirred until fully dissolved to prepare a mixture. The mixture was then transferred to a 1000 mL hydrothermal reactor and kept at 160 °C for 12 h. After the reaction was complete, the mixture was cooled to room temperature, vacuum dried, and then ground to obtain indium zinc sulfide nanoflowers.

[0089] The indium zinc sulfide nanoflower photocatalyst prepared in Comparative Example 1 has a diameter of 5-7 μm and a flower-like microsphere structure, without any bimetallic silver-nickel alloy nanoparticles. Although the three-dimensional indium zinc sulfide nanoflower structure is beneficial for mass transfer between reactants and products, enhances surface reaction kinetics, and exposes abundant active sites; its open flower-like morphology facilitates multiple reflections and absorptions of light, and it possesses a high specific surface area and short charge transport pathways constructed from ultrathin nanosheets—all structural advantages that contribute to improving the photocatalytic performance of indium zinc sulfide—this pure-phase indium zinc sulfide nanoflower photocatalyst still exhibits weak UV-Vis light absorption and low photocatalytic activity in treating heavy metal ions and organic pollutants (such as coal slag) from filtered coal mine water. Figure 5 This is due to limited ultraviolet-visible light absorption and rapid electron-hole recombination.

[0090] Comparative Example 2 This comparative example provides a photocatalyst that uses indium zinc sulfide nanoflowers as a support, on which nickel nanoparticles are loaded. The loading amount of nickel nanoparticles is 2% of the mass of the indium zinc sulfide nanoflowers.

[0091] The method for preparing the photocatalyst provided in this embodiment is as follows: Add 6.82 mL of 0.1 M nickel nitrate solution and 2 g of indium zinc sulfide nanoflower powder to 600 mL of deionized water, stir and dissolve thoroughly to prepare the first mixture.

[0092] Add 5 mL of 0.5 M sodium borohydride solution to the first mixture, stir for 1 hour and mix thoroughly to prepare the second mixture. Wash, vacuum dry and grind the second mixture to prepare the photocatalyst.

[0093] In this comparative study, nickel nanoparticles were grown on the surface of indium zinc sulfide nanoflowers as a photocatalyst. UV-Vis spectrophotometry demonstrated that, compared to the single-structure indium zinc sulfide nanoflowers, the presence of a small amount of nickel nanoparticles enhanced the light absorption capacity of the photocatalyst, significantly expanding the visible light absorption limit and improving the utilization rate of sunlight (e.g., ...). Figure 4 Meanwhile, due to the excellent electrical conductivity of nickel nanoparticles, the separation of photogenerated electrons and holes in indium zinc sulfide nanoflowers is promoted, which is beneficial to the transport of charge carriers and enhances the photocatalytic performance of the catalyst. Compared with Comparative Example 1, this photocatalyst shows improved light absorption under visible light and also exhibits enhanced photocatalytic activity in treating heavy metal ions and organic pollutants (such as coal slag) in coal mine water under both ultraviolet and visible light. Figure 5 ).

[0094] Comparative Example 3 This comparative example provides a photocatalyst that uses indium zinc sulfide nanoflowers as a carrier, on which silver nanoparticles are loaded. The loading amount of silver nanoparticles is 2% of the mass of the indium zinc sulfide nanoflowers.

[0095] The method for preparing the photocatalyst provided in this embodiment is as follows: Add 3.71 mL of 0.1 M silver nitrate solution and 2 g of indium zinc sulfide nanoflower powder to 600 mL of deionized water, stir and dissolve thoroughly to prepare the first mixture.

[0096] Add 5 mL of 0.5 M sodium borohydride solution to the first mixture, stir for 1 hour, and mix thoroughly to prepare the second mixture. Wash, vacuum dry, and grind the second mixture to obtain the photocatalyst.

[0097] In this comparative study, silver nanoparticles were grown on the surface of indium zinc sulfide nanoflowers as a photocatalyst. UV-Vis spectrophotometry demonstrated that, compared to single-structure indium zinc sulfide nanoflowers, the presence of a small amount of silver nanoparticles enhanced the light absorption capacity of the photocatalyst, broadened the visible light absorption limit, and improved the utilization rate of sunlight (e.g., ...). Figure 4 Simultaneously, due to the excellent electrical conductivity of silver nanoparticles, the separation of photogenerated electrons and holes in indium zinc sulfide nanoflowers is promoted, which is beneficial to the transport of charge carriers and enhances the photocatalytic performance of the catalyst. Compared with Examples 1, 2, 3, Comparative Examples 1 and 2, this photocatalyst also shows enhanced photocatalytic activity in treating heavy metal ions and organic pollutants (such as coal slag) in coal mine water filtered under ultraviolet and visible light. Figure 5 ).

[0098] Performance testing: 1. Light absorption capacity Figure 4 The images show the UV-Vis absorption spectra of the photocatalysts prepared in Examples 3, 1, 2, and 3 of this invention. Figure 4 It can be seen that the addition of nickel can significantly improve the light absorption capacity of the photocatalyst.

[0099] 2. Performance of photocatalytic treatment of coal mine water Using the products from the above examples and comparative examples as photocatalysts, heavy metal ions and organic pollutants were treated in coal mine water after filtration of coal slag. The photocatalytic experiment was conducted in an XPA photochemical reactor using a 500 W mercury lamp (CEL-WLAX500, Beijing Zhongjiao Jinyuan Co., Ltd.) equipped with a filter with a wavelength greater than 800 nm. A circulating water bath was used to maintain the reaction temperature at 25°C. Specifically, 20 mg of photocatalyst was dispersed in 20 mL of coal mine water after filtration of coal slag, and the photocatalytic experiment was conducted for 90 minutes. Before illumination, the mixture was magnetically stirred in the dark for 30 minutes to reach adsorption-desorption equilibrium. During illumination, a portion of the suspension was removed from the reactor at each time interval. The concentrations of typical heavy metal ions (Cr(VI)) and organic pollutants (phenol) in the solution were determined using a spectrophotometer (UV-3101PC).

[0100] Test results as follows Figure 5 As shown. Figure 5 The photocatalysts prepared in the examples and comparative examples were compared in their photocatalytic performance in treating heavy metal ions and organic pollutants from coal mine water after filtering coal slag under ultraviolet and visible light irradiation. Compared with indium zinc sulfide nanoflowers, the photocatalyst's performance in treating coal mine water increased with the loading of the bimetallic silver-nickel alloy. The optimal performance was achieved when the molar ratio of silver to nickel was 75:25. Furthermore, the photocatalyst exhibited the best performance in treating coal mine water when the loading mass ratio of the bimetallic silver-nickel alloy nanoparticles was 2%. Therefore, the optimal molar ratio of silver to nickel in the bimetallic silver-nickel alloy indium zinc sulfide composite photocatalyst is 75:25, and the optimal loading mass ratio of the bimetallic silver-nickel alloy nanoparticles is 2%.

[0101] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A photocatalyst characterized by comprising: The silver-nickel alloy nanoparticles are loaded on the surface of the zinc indium sulfide nanoflower.

2. The photocatalyst according to claim 1, wherein The molar ratio of silver to nickel in the silver-nickel alloy nanoparticles is (1-100):(1-100), preferably (25-75):(25-75), and more preferably 75:

25. Preferably, the silver-nickel alloy nanoparticles account for 1-5% of the mass of the zinc indium sulfide nanoflower, preferably 1-3%, and more preferably 2%.

3. The photocatalyst according to claim 1, wherein The diameter of the zinc indium sulfide nanoflower is 5-7 μm. Preferably, the particle size of the silver-nickel alloy nanoparticles is 4-6 nm.

4. A method for producing the photocatalyst according to any one of claims 1 to 3, characterized by, The method comprises the following steps: Mixing zinc indium sulfide nanoflower, silver salt solution, nickel salt solution and water to obtain a mixed solution; Adding sodium borohydride to the mixed solution, stirring, washing, drying and grinding after reaction to obtain a photocatalyst.

5. The production method according to claim 4, wherein The method for preparing the zinc indium sulfide nanoflower comprises the following steps: Mixing zinc salt, indium salt, thioacetamide and water, stirring, and then performing hydrothermal reaction, cooling to room temperature after reaction, drying and grinding to obtain zinc indium sulfide nanoflower; Preferably, the temperature of the hydrothermal reaction is 150-170℃, the time is 10-14 h, and the heating rate is 1.3-3℃ / min.

6. The production method according to claim 4, wherein The silver salt includes any one or several of silver nitrate, silver fluoride and silver perchlorate, and preferably silver nitrate; Preferably, the nickel salt includes any one or several of nickel sulfate, nickel chloride and nickel nitrate, and preferably nickel nitrate; Preferably, the concentration of the silver salt solution is 0.05-0.15 M, the concentration of the nickel salt solution is 0.05-0.15 M, and the amount ratio of the zinc indium sulfide nanoflower, silver salt solution, nickel salt solution and water is (1.32-4.04 g):(0.01-3.71 mL):(0.01-6.82 mL):(500-700 mL).

7. The production method according to claim 4, wherein Adding sodium borohydride solution to the mixed solution and stirring for 0.5-3 h; Preferably, the concentration of the sodium borohydride solution is 0.4-0.6 M, and the amount is 4-6 mL.

8. Application of the photocatalyst of any one of claims 1-3 or prepared by the method of any one of claims 4-7 in water treatment. Preferably, the water includes coal mine well water.

9. A method of water treatment, characterized by, The method comprises the following steps: Adding the photocatalyst of any one of claims 1-3 or prepared by the method of any one of claims 4-7 to water to be treated and irradiating.

10. The method of claim 9, wherein, Stirring the water solution to be treated containing the photocatalyst in the dark before irradiation until adsorption-desorption equilibrium is reached; Preferably, the concentration of the photocatalyst in the water to be treated is 0.5-1.5 mg / mL.

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