Catalytic algae removal material and preparation method thereof

Abstract

The invention provides a catalytic algae removal material and a preparation method thereof. The preparation method comprises the following steps: adding Ni (OH) 2 and NaFeS2 into distilled water according to a mass ratio of 1: (9-11), stirring for 8-12 min, adjusting the pH value to 6.5-7.5, placing the obtained reaction system in a water bath environment at 110-130 DEG C, heating for 5-7 h to prepare Ni (OH) 2 / NaFeS2, and centrifuging, cleaning and drying the obtained Ni (OH) 2 / NaFeS2 to obtain the catalytic algae removal material. According to the invention, based on an energy band matching principle, two semiconductors Ni (OH) 2 and NaFeS2 are coupled to prepare the composite material Ni (OH) 2 / NaFeS2 with a heterostructure. The energy level difference between the two enhances the absorption of visible light by the catalytic algae removal material, promotes the separation of photogenerated charges, enhances the photocatalytic effect of the algae removal material, and improves the algae removal efficiency.

Description

Technical Field

[0001] This application relates to the field of sewage treatment, and more particularly, to a catalytic algaecide material and a preparation method thereof. Background Art

[0002] Cyanobacteria are the earliest photosynthetic autotrophs on Earth and appear in water bodies all over the world. When water bodies are polluted and certain nutrients are in excess, cyanobacteria will form a dominant population and multiply in large numbers, resulting in a dense floating layer on the water surface, which is called water bloom. The water bloom phenomenon seriously disrupts the ecological balance of water bodies and even affects people's normal life.

[0003] Current algaecide technologies mainly utilize photocatalysts. Photocatalytic oxidation is a low-cost, green, and effective algaecide method. Among them, nickel hydroxide (Ni(OH) 2 ) as a spinel-type ferrite magnetic material is widely used due to its large specific surface area and good photocatalytic activity. However, since Ni(OH) 2 is a photocatalyst driven by ultraviolet light and cannot fully utilize the visible light in the solar spectrum, its photocatalytic effect is limited and the algaecide efficiency is low. Summary of the Invention

[0004] To solve the above problems, this application provides a catalytic algaecide material and a preparation method thereof. Based on the principle of energy band matching, this application couples two semiconductors, Ni(OH) 2 and NaFeS 2 , to prepare a composite material Ni(OH) 2 / NaFeS 2 (NiFS) with a heterostructure. The energy level difference between the two enhances the absorption of visible light by the composite, promotes the separation of photo-generated charges, enhances the photocatalytic effect of the catalytic algaecide material, and effectively improves the algaecide efficiency.

[0005] In a first aspect, this application provides a preparation method of a catalytic algaecide material, and the preparation method includes: Adding Ni(OH) 2 and NaFeS 2 with a mass ratio of 1:(9 - 11) to distilled water, stirring for 8 - 12 min, adjusting the pH to 6.5 - 7.5, placing the obtained reaction system in a water bath environment at 110 - 130 °C and heating for 5 - 7 h to prepare Ni(OH) 2 / NaFeS 2 . After centrifuging, washing, and drying the obtained Ni(OH) 2 / NaFeS 2 , a catalytic algaecide material is obtained.

[0006] Optionally, adjusting the pH to 6.5 - 7.5 includes: adding a NaOH solution with a concentration of 0.8 - 1.2 mol / L to the stirred system to adjust the pH to 6.5 - 7.5.

[0007] Optionally, the drying includes: placing the Ni(OH) 2 / NaFeS 2 under vacuum and drying at 60 - 80 °C for 12 - 24 h.

[0008] Optionally, the washing includes: alternately washing 6 - 10 times with distilled water and ethanol.

[0009] Optionally, the temperature of the water bath environment is between 115 - 125 °C.

[0010] Optionally, the preparation method of the NaFeS 2 includes: Adding Fe(NO 3 ) 3 ·9H 2 O and Na 2 S·9H 2 O to distilled water, dissolving at 90 - 110 °C for 8 - 12 min, and then stirring at 50 - 70 °C for 25 - 35 min to obtain a mixed solution; Adding NaOH to the mixed solution, adjusting the pH to 6.5 - 7.5, and heating in a water bath at 170 - 190 °C for 24 - 26 h to obtain the NaFeS 2 .

[0011] Optionally, the molar ratio of Fe(NO 3 ) 3 ·9H 2 O and Na 2 S·9H 2 O is 1:(2 - 4).

[0012] Optionally, the preparation method of the Ni(OH) 2 includes: Mixing NiSO 4 ·6H 2 O and FeSO 4 ·7H 2 O with a mass ratio of (0.5 - 0.6):1, stirring for 8 - 12 min, adjusting the pH to 6.5 - 7.5, and placing the adjusted system in a water bath environment at 110 - 130 °C and heating for 5 - 6 h. The obtained product is the Ni(OH) 2 .

[0013] In a second aspect, the present application provides a catalytic algaecide material prepared by the preparation method of the catalytic algaecide material in the first aspect above.

[0014] In a third aspect, the present application provides an application of a catalytic alga-removing material prepared by the preparation method of the catalytic alga-removing material in the first aspect above. Under the action of visible light, the catalytic alga-removing material photocatalytically removes algae plants in sewage.

[0015] Beneficial effects: The present application provides a catalytic alga-removing material and a preparation method thereof. Among them, Ni(OH) 2 As a semiconductor photocatalyst, it has high photocatalytic activity and thermochemical stability. After adding NaFeS 2 it causes a red shift in its UV-vis, further enhancing the absorption of visible light, expanding the absorption range of visible light, facilitating the separation of photo-generated carriers and the narrowing of the band gap, thereby enhancing the photocatalytic effect of the catalytic alga-removing material and improving the alga-removing efficiency. In addition, the catalytic alga-removing material prepared in the present application has good stability, can be recycled, and has better economic benefits. Description of the drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 is the process flow chart of the preparation method of the catalytic alga-removing material proposed in the embodiment of the present application; Figure 2 is the SEM image of the Ni(OH) 2 / NaFeS 2 composite material prepared in Example 1 of the present application; Figure 3 is the N )2 adsorption-desorption isotherm diagram of Ni(OH 2 / NaFeS 2 prepared in Example 1 of the present application; Figure 4 is the Fourier infrared spectrum of Ni(OH) 2 / NaFeS 2 prepared in Example 1 of the present application; Figure 5 is the ultraviolet diffuse reflection spectrum diagram of the nanomaterials prepared in Example 1, Comparative Example 1 and Comparative Example 2 of the present application; Figure 6 is the schematic diagram of the photocatalytic experimental device and experimental process in the embodiment of the present application; Figure 7It is the NaFeS prepared in Comparative Example 1 and Comparative Example 2 of this application 2 Photocatalytic nanomaterials and Ni(OH) 2 Performance comparison chart of visible-light photocatalytic removal of Microcystis aeruginosa by photocatalysts; Figure 8 It is the Ni(OH) prepared in Example 1 of this application 2 / NaFeS 2 Stable photocatalytic performance chart of the composite material. Detailed implementation manners

[0018] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present application.

[0019] In the accompanying drawings, sometimes for clarity, the sizes of the components, the thicknesses of the layers or the regions may be exaggerated. Therefore, any implementation manner of the present disclosure is not necessarily limited to the sizes shown in the drawings, and the shapes and sizes of the components in the drawings do not reflect the true proportions. In addition, the accompanying drawings schematically show ideal examples, and any implementation manner of the present disclosure is not limited to the shapes or values shown in the drawings.

[0020] In related technologies, cyanobacteria are the earliest photosynthetic autotrophic organisms on Earth and appear in water bodies all over the world. When water bodies are polluted and certain nutrients are in excess, cyanobacteria often form a dominant population and multiply in large numbers, resulting in a dense floating layer on the water surface, thereby causing the water body to change color and emit an odor. This large-scale outbreak of cyanobacteria is called water bloom.

[0021] In the past decade, frequent outbreaks of algal blooms have caused harm to lakes and reservoirs all over the world. The outbreak of cyanobacteria will consume most of the dissolved oxygen in the water body, deprive other organisms of the necessary oxygen, and seriously damage the ecological balance of the water body. In addition, a large amount of cyanobacteria form thick and malodorous floating foams, seriously affecting people's normal life. The secondary metabolites produced by cyanobacteria are called cyanotoxins, including several types such as neurotoxins, hepatotoxins, cytotoxins and endotoxins, which pose a serious threat to the health and survival of humans and other organisms. Therefore, there is an urgent need to find a solution to control cyanobacterial water blooms.

[0022] Microcystis aeruginosa is a common dominant population during algal blooms, and the microcystins it produces are highly hepatotoxic and widely present in freshwater ecosystems around the world. Although current algal removal technologies (such as ultrasonic method, chemical method, biological inhibition method) have certain mitigation effects, there are still problems in terms of cost, energy consumption, pollution management, etc. Photocatalytic technology has received extensive attention in recent years due to its advantages such as green economy, good degradation effect, and simple operation. However, traditional photocatalytic technology has defects such as low migration efficiency of photo-generated carriers, low utilization rate of visible light, inappropriate semiconductor energy band positions, and insufficient number of surface active sites, which greatly limit the application of photocatalysis. Therefore, to apply photocatalytic technology to the control of cyanobacterial blooms, it is necessary to reasonably design and adjust photocatalysts according to the characteristics of algae.

[0023] Photocatalytic oxidation is a low-cost, green, and effective algal removal method. Nickel hydroxide (Ni(OH) 2 ) as a spinel-type ferrite magnetic material has attracted much attention due to its large specific surface area, unique magnetic separation characteristics, and good photocatalytic activity. Combining it with a semiconductor photocatalyst with a suitable band gap not only realizes the magnetic separation of the photocatalyst but also exhibits excellent photocatalytic effects.

[0024] However, the disadvantage is that Ni(OH) 2 is a photocatalyst driven by ultraviolet light and cannot fully utilize the visible light in the solar spectrum, which severely restricts the application of Ni(OH) 2 . Sodium iron disulfide (NaFeS 2 ) as a widely studied photocatalyst has characteristics such as non-toxicity, good stability, and high photocatalytic oxidation ability, and is considered an emerging strategy for treating cyanobacterial blooms with practical application prospects.

[0025] In view of this, this application proposes a catalytic algal removal material and its preparation method. Based on the principle of energy band matching, two semiconductors, Ni(OH) 2 and NaFeS 2 , are coupled to prepare a heterostructure composite photocatalytic system Ni(OH) 2 / NaFeS 2 (NiFS). Compared with the single-component Ni(OH) 2 and NaFeS 2 , the photocatalytic performance of the obtained composite Ni(OH) 2 / NaFeS 2 (NiFS) has been greatly improved, which is attributed to the energy level difference between the two enhancing the visible light absorption of the composite and promoting the separation of photo-generated charges. The preparation method provided in this application is simple, has a higher removal rate and better stability for Microcystis aeruginosa under visible light, and can be reused.

[0026] An embodiment of the present application provides a catalytic algae-removing material and a preparation method thereof. The preparation method refers to Figure 1 , and the method includes: Step S1: Add Ni(OH) with a mass ratio of 1:(9-11) 2 and NaFeS 2 to distilled water and stir for 8-12 min; Specifically, when implemented, the mass ratio of Ni(OH) 2 and NaFeS 2 can be 1:9, 1:10 or 1:11.

[0027] Specifically, when implemented, add Ni(OH) 2 and NaFeS 2 to distilled water, ultrasonically mix for 10 min, and then stir the stirred system for 8-12 min to uniformly disperse the above two components in distilled water.

[0028] Specifically, when implemented, add Ni(OH) 2 and NaFeS 2 to distilled water and stir for 8 min, 9 min, 10 min, 11 min or 12 min. Preferably, add Ni(OH) 2 and NaFeS 2 to distilled water and stir for 10 min.

[0029] Step S2: Adjust the pH to 6.5-7.5, and place the obtained reaction system in a water bath environment at 110-130 °C and heat for 5-7 h to obtain Ni(OH) 2 / NaFeS 2 ; Specifically, when implemented, adjust the pH to 6.5, 7 or 7.5 to make Ni(OH) 2 and NaFeS 2 react in a neutral environment. The neutral environment helps to maintain the relative stability of Ni(OH) 2 and NaFeS 2 , is not prone to violent chemical reactions, is conducive to controlling the reaction process, and avoids the generation of unnecessary by-products.

[0030] Specifically, adjusting the pH to 6.5-7.5 includes: adding a NaOH solution with a concentration of 0.8-1.2 mol / L to the stirred system and adjusting the pH to 6.5-7.5.

[0031] In specific implementation, NaOH solutions with concentrations of 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, or 1.2 mol / L are added to the stirred system, and the pH is adjusted to 6.5 - 7.5. Preferably, a NaOH solution with a concentration of 1.0 mol / L is added to the stirred system.

[0032] In specific implementation, the temperature of the water bath environment ranges from 115 to 125 °C.

[0033] In specific implementation, the obtained reaction system is transferred to a hydrothermal reaction kettle and heated in an oven at 110 °C, 115 °C, 120 °C, 125 °C, or 130 °C for 5, 6, or 7 h to prepare Ni(OH) 2 / NaFeS 2 。

[0034] Preferably, the obtained reaction system is transferred to a hydrothermal reaction kettle and heated in an oven at 120 °C for 5 h to prepare Ni(OH) 2 / NaFeS 2 。

[0035] The water bath heating at the above temperature helps to promote the reaction and accelerate the reaction rate, enabling the Ni(OH) 2 and NaFeS 2 in the reaction system to react fully and prepare Ni(OH) 2 / NaFeS 2 。

[0036] Step S3: After centrifuging, washing, and drying the obtained Ni(OH) 2 / NaFeS 2 a catalytic algaecide material is obtained.

[0037] In specific implementation, the washing includes: alternately washing 6 - 10 times with distilled water and ethanol.

[0038] In specific implementation, the washing includes: alternately washing 6, 7, 8, 9, or 10 times with distilled water and ethanol.

[0039] After washing, it can avoid the residual of other ions in Ni(OH) 2 / NaFeS 2 to ensure the purity of Ni(OH) 2 / NaFeS 2 and also avoid the influence of the remaining other ions on the photocatalytic effect of Ni(OH) 2 / NaFeS 2 。

[0040] In specific implementation, the drying includes: drying Ni(OH) 2 / NaFeS2 Place it under vacuum and dry at 60 - 80°C for 12 - 24 h.

[0041] In specific implementation, drying includes: Ni(OH) 2 / NaFeS 2 Place it under vacuum and dry at a temperature of 60°C, 65°C, 70°C, 75°C or 80°C for 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, 21 h, 22 h, 23 h or 24 h.

[0042] Drying can further remove the residual ions on the product Ni(OH) 2 / NaFeS 2 and further improve the purity of the product Ni(OH) 2 / NaFeS 2 .

[0043] In specific implementation, the preparation method of NaFeS 2 includes: Add Fe(NO 3 ) 3 ·9H 2 O and Na 2 S·9H 2 O into distilled water, dissolve at 90 - 110°C for 8 - 12 min, and then stir at 50 - 70°C for 25 - 35 min to obtain a mixed solution; Add NaOH to the mixed solution, adjust the pH to 6.5 - 7.5, and heat in a water bath at 170 - 190°C for 24 - 26 h to obtain NaFeS 2 .

[0044] In specific implementation, the molar ratio of Fe(NO3) 3 ·9H 2 O and Na 2 S·9H 2 O is 1:(2 - 4).

[0045] In specific implementation, the molar ratio of Fe(NO3) 3 ·9H 2 O and Na 2 S·9H 2 O is 1:2, 1:3 or 1:4.

[0046] Limiting the molar ratio of the above Fe(NO3) 3 ·9H 2 O and Na 2 S·9H 2 O is to ensure the formation of FeS 2 instead of other sulfides. If S 2-Excess may produce FeS or other polysulfides; if Fe 3+ is in excess, Fe 2 S 3 or other iron sulfides may be produced. Therefore, under the molar ratio restricted in this application, other sulfides can be avoided, and high-purity NaFeS 2 can be obtained.

[0047] Specifically, when implementing, Fe(NO 3 ) 3 ·9H 2 O and Na 2 S·9H 2 O are added to distilled water and dissolved at 90 °C, 100 °C or 110 °C for 8 min, 9 min or 10 min. Then the mixed system is placed in an environment of 50 °C, 55 °C, 60 °C, 65 °C or 70 °C and stirred for 25 min, 28 min, 30 min, 32 min or 35 min to prepare a mixed solution, enabling Fe(NO 3 ) 3 ·9H 2 O and Na 2 S·9H 2 O to be fully and uniformly dissolved in distilled water, providing a homogeneous environment for subsequent reactions.

[0048] Specifically, when implementing, solid NaOH is added to the mixed solution to adjust the pH to 6.5, 7 or 7.5 to make the solution neutral, so that subsequent reactions can proceed in a neutral environment.

[0049] Specifically, the mixed solution with the pH adjusted to 7 is transferred to a hydrothermal reaction kettle and placed in an oven at 170 °C, 180 °C or 190 °C for 24 h, 25 h or 26 h. Preferably, it is placed in an oven at 180 °C for 24 h, then cooled to room temperature, washed several times with ethanol and acetone, and then dried at 80 °C. The formed solid is NaFeS 2 .

[0050] The above reaction temperature and time help the raw materials to react fully to obtain a sufficient amount of the product NaFeS 2 .

[0051] Specifically, the preparation method of Ni(OH) 2 includes: Mixing NiSO 4 ·6H 2 O and FeSO 4 ·7H 2After mixing, stir for 8 - 12 min, adjust the pH to 6.5 - 7.5, and place the adjusted system in a water bath at 110 - 130 °C and heat for 5 - 6 h. The resulting product is Ni(OH) 2 .

[0052] Specifically, when implemented, the mass ratio of NiSO 4 ·6H 2 O and FeSO 4 ·7H 2 O is 0.5:1 or 0.6:1.

[0053] Specifically, when implemented, NiSO 4 ·6H 2 O and FeSO 4 ·7H 2 O with a mass ratio of 0.6:1 are mixed and stirred for 8 min, 9 min, 10 min, 11 min, or 12 min. Preferably, the stirring time is 10 min.

[0054] Specifically, when implemented, adjust the pH to 6.5, 7, or 7.5 to make the reaction proceed in a neutral environment.

[0055] Specifically, when implemented, transfer the adjusted system to a hydrothermal reaction kettle and heat it in an oven at 110 °C, 115 °C, 120 °C, 125 °C, or 130 °C for 5 h or 6 h. The resulting product is Ni(OH) 2 .

[0056] This application also provides a composite material prepared by the above - mentioned preparation method. This composite material has a higher removal rate of Microcystis aeruginosa under visible light, better stability, can be reused, and has higher economic benefits.

[0057] This application also provides an application of the composite material prepared by the above - mentioned preparation method. Under the action of visible light, the composite material photocatalytically removes algae plants in sewage.

[0058] The following uses specific examples to further describe the preparation method of this application. It should be noted that nickel sulfate hexahydrate (NiSO 4 ·6H 2 O), ferrous sulfate heptahydrate (FeSO 4 ·7H 2 O), sodium hydroxide (NaOH), sodium sulfide nonahydrate (Na 2 S·9H 2 O), iron(III) nitrate nonahydrate (Fe(NO 3 ) 3 ·9H 2O) were all purchased from Aladdin (Shanghai, China). All reagents can be used without further purification, and distilled water was used in all experimental procedures.

[0059] Example Example 1 Step 1: Add 40 mM Fe(NO 3 ) 3 ·9H 2 O and 120 mM Na 2 S·9H 2 O to distilled water, dissolve at 100 °C for 10 min, then continue stirring at 60 °C for 30 min to obtain a mixed solution. Add 2 g of NaOH to the mixed solution and adjust the pH to 7; Transfer the adjusted solution to a hydrothermal reaction kettle and place it in an oven at 180 °C for 24 hours; subsequently, cool to room temperature, wash the obtained product several times with distilled water and ethanol, and then dry it at 80 °C to form solid NaFeS 2 ; Step 2: Add 0.526 g of NiSO 4 ·6H 2 O and 1.132 g of FeSO 4 ·7H 2 O to distilled water, stir for 10 min, and adjust the pH to 7 with 1 mol / L NaOH solution; Transfer the obtained reaction solution to a hydrothermal reaction kettle, heat it in an oven at 120 °C for 6 h, perform centrifugation after the reaction, wash it 8 times alternately with distilled water and ethanol, and finally place the prepared Ni(OH) 2 in a vacuum, and then dry it at 70 °C for 18 h to obtain solid Ni(OH) 2 ; Step 3: Place 1.1 g of Ni(OH) 2 and 0.013 g of NaFeS 2 in centrifuge tubes containing distilled water and ultrasonically homogenize them. Then pour the solutions into a beaker in sequence and stir for 10 min. Adjust the pH to 7 with 1 mol / L NaOH solution; Transfer the obtained reaction system to a hydrothermal reaction kettle, heat it in an oven at 120 °C for 6 h, perform centrifugation after the reaction, wash it 8 times alternately with distilled water and ethanol, and finally place the prepared Ni(OH) 2 / NaFeS 2 in a vacuum, and then dry it at 70 °C for 18 h to obtain the composite material for catalytic algae removal.

[0060] Based on Example 1, the structure of the composite material for catalytic algae removal prepared in Example 1 was investigated.

[0061] Refer toFigure 2 , Figure 2 is the SEM image of the Ni(OH) 2 / NaFeS 2 composite material prepared in Example 1 of this application. Figure 2 It shows that the Ni(OH) 2 / NaFeS 2 material is a nanosheet structure.

[0062] The nanosheet structure can absorb visible light and ultraviolet light more effectively, enabling the photocatalyst to act in a wider spectral range.

[0063] Based on Example 1, the adsorption capacity of the composite material for catalytic algae removal prepared in Example 1 was investigated.

[0064] Refer to Figure 3 , Figure 3 is the N 2 / NaFeS 2 adsorption - desorption isotherm diagram of 2 in which "■" represents adsorption and "●" represents desorption. Figure 3 It shows that the force between the composite material for catalytic algae removal and the adsorbate is strong, and the adsorption effect on organic pollutants is good, with good adsorption and photocatalytic synergy ability. Figure 3

[0065] Based on Example 1, it was investigated whether Ni(OH) 2 and NaFeS 2 were successfully compounded to obtain Ni(OH) 2 2 / NaFeS 2 .

[0066] Refer to Figure 4 , Figure 4 is the Fourier infrared spectrum of Ni(OH) 2 / NaFeS 2 prepared in Example 1 of this application, Figure 4 in which "1" represents NiFS, "2" represents Ni(OH) 2 , "3" represents NaFeS 2 . Figure 4 It shows that in the FT - IR spectrum of NaFeS 2 , the two peaks at 3378 and 3460 cm -1 overlap, which are the characteristic vibration peaks of water molecules bound in the NaFeS 2 structure. The water molecules and hydroxyl groups adsorbed on the surface of NaFeS 2 can be converted into hydroxyl radicals in the photocatalytic reaction for oxidizing organic pollutants; 615 cm -1 The band at is attributed to Fe-S. For Ni(OH) 2 , strong characteristic bands appear at 3410 and 1640 cm -1 , which are attributed to the -OH stretching vibration of water and the deformation vibration of the H-O-H bond. The peak at 518 cm -1 is attributed to the vibration of the Ni-O-H bond. Ni(OH) 2 / NaFeS 2 In the composite material, there are typical absorption peaks of NaFeS 2 and Ni(OH) 2 , indicating the successful composite of the two materials.

[0067] Example 2 The difference between Example 2 and Example 1 lies in that the reaction conditions in Step 3 are different.

[0068] Step 1: Add 40 mM Fe(NO 3 ) 3 ·9H 2 O and 120 mM Na 2 S·9H 2 O to distilled water, dissolve at 100 °C for 10 min, then continue stirring at 60 °C for 30 min to obtain a mixed solution. Add 2 g of NaOH to the mixed solution and adjust the pH to 7; Transfer the adjusted solution to a hydrothermal reaction kettle and place it in an oven at 180 °C for 24 hours; subsequently, cool to room temperature, wash the obtained product several times with distilled water and ethanol, and then dry it at 80 °C to form solid NaFeS 2 ; Step 2: Add 0.526 g of NiSO 4 ·6H 2 O and 1.132 g of FeSO 4 ·7H 2 O to distilled water, stir for 10 min, and adjust the pH to 7 with 1 mol / L NaOH solution; Transfer the obtained reaction solution to a hydrothermal reaction kettle, heat it in an oven at 120 °C for 6 h, centrifuge after the reaction, wash it 8 times alternately with distilled water and ethanol, and finally place the prepared Ni(OH) 2 in a vacuum and dry it at 70 °C for 18 h to obtain solid Ni(OH) 2 ; Step 3: Mix 0.9 g of Ni(OH) 2 and 0.013 g of NaFeS 2They were respectively placed in centrifuge tubes filled with distilled water and ultrasonicated to be uniform. Then the solutions were successively poured into a beaker and stirred for 10 min, and the pH was adjusted to 7 with 1 mol / L NaOH solution; The obtained reaction system was transferred to a hydrothermal reactor and heated in an oven at 120 °C for 6 h. After the reaction ended, centrifugation was carried out, and then it was alternately washed 8 times with distilled water and ethanol. Finally, the prepared Ni(OH) 2 / NaFeS 2 was placed in a vacuum and then dried at 70 °C for 18 h to obtain the composite material for catalytic algae removal.

[0069] Example 3 The difference between Example 3 and Example 1 is that the reaction conditions in Step 3 are different.

[0070] Step 1: 40 mM Fe(NO 3 ) 3 ·9H 2 O and 120 mM Na 2 S·9H 2 O were added to distilled water, dissolved at 100 °C for 10 min, and then continuously stirred at 60 °C for 30 min to obtain a mixed solution. 2 g NaOH was added to the mixed solution to adjust the pH to 7; The adjusted solution was transferred to a hydrothermal reactor and placed in an oven at 180 °C for 24 h; subsequently, it was cooled to room temperature, and the obtained product was washed several times with distilled water and ethanol, and then dried at 80 °C to form solid NaFeS 2 ; Step 2: 0.526 g NiSO 4 ·6H 2 O and 1.132 g FeSO 4 ·7H 2 O were added to distilled water, stirred for 10 min, and the pH was adjusted to 7 with 1 mol / L NaOH solution; The obtained reaction solution was transferred to a hydrothermal reactor and heated in an oven at 120 °C for 6 h. After the reaction ended, centrifugation was carried out, and then it was alternately washed 8 times with distilled water and ethanol. Finally, the prepared Ni(OH) 2 was placed in a vacuum and dried at 70 °C for 18 h to obtain solid Ni(OH) 2 ; Step 3: 1 g Ni(OH) 2 and 0.013 g NaFeS 2 were respectively placed in centrifuge tubes filled with distilled water and ultrasonicated to be uniform. Then the solutions were successively poured into a beaker and stirred for 10 min, and the pH was adjusted to 7 with 1 mol / L NaOH solution; Transfer the obtained reaction system to a hydrothermal reaction kettle, heat it in an oven at 120 °C for 6 h, perform centrifugation after the reaction, wash it alternately with distilled water and ethanol 8 times, and finally prepare the obtained Ni(OH) 2 / NaFeS 2 Place it in a vacuum, and then dry it at a temperature of 70 °C for 18 h to obtain a composite material for catalytic algae removal.

[0071] Example 4 The difference between Example 4 and Example 1 is that the reaction conditions in Step 3 are different.

[0072] Step 1: Add 40 mM Fe(NO 3 ) 3 ·9H 2 O and 120 mM Na 2 S·9H 2 O to distilled water, dissolve it at 100 °C for 10 min, then continue to stir at 60 °C for 30 min to obtain a mixed solution, add 2 g of NaOH to the mixed solution, and adjust the pH to 7; Transfer the adjusted solution to a hydrothermal reaction kettle and place it in an oven at 180 °C for 24 hours; then, cool it to room temperature, wash the obtained product several times with distilled water and ethanol, and then dry it at 80 °C to form a solid NaFeS 2 ; Step 2: Add 0.526 g of NiSO 4 ·6H 2 O and 1.132 g of FeSO 4 ·7H 2 O to distilled water, stir for 10 min, and adjust the pH to 7 with 1 mol / L NaOH solution; Transfer the obtained reaction solution to a hydrothermal reaction kettle, heat it in an oven at 120 °C for 6 h, perform centrifugation after the reaction, wash it alternately with distilled water and ethanol 8 times, and finally prepare the obtained Ni(OH) 2 Place it in a vacuum and dry it at a temperature of 70 °C for 18 h to obtain a solid Ni(OH) 2 ; Step 3: Place 1.1 g of Ni(OH) 2 and 0.013 g of NaFeS 2 in centrifuge tubes filled with distilled water and ultrasonically homogenize them, then pour the solutions into a beaker in sequence and stir for 10 min, and adjust the pH to 7 with 1 mol / L NaOH solution; Transfer the obtained reaction system to a hydrothermal reaction kettle, heat it in an oven at 110 °C for 7 h, perform centrifugation after the reaction, wash it alternately with distilled water and ethanol 8 times, and finally prepare the obtained Ni(OH) 2 / NaFeS2 Place it in a vacuum and dry it at 70 °C for 18 h to obtain the composite material for catalytic algae removal.

[0073] Example 5 The difference between Example 5 and Example 1 lies in the different reaction conditions in Step 3.

[0074] Step 1: Add 40 mM Fe(NO 3 ) 3 ·9H 2 O and 120 mM Na 2 S·9H 2 O to distilled water, dissolve it at 100 °C for 10 min, then continue stirring at 60 °C for 30 min to obtain a mixed solution. Add 2 g of NaOH to the mixed solution and adjust the pH to 7; Transfer the adjusted solution to a hydrothermal reaction kettle and place it in an oven at 180 °C for 24 hours; subsequently, cool it to room temperature, wash the obtained product several times with distilled water and ethanol, and then dry it at 80 °C to form solid NaFeS 2 ; Step 2: Add 0.526 g of NiSO 4 ·6H 2 O and 1.132 g of FeSO 4 ·7H 2 O to distilled water, stir for 10 min, and adjust the pH to 7 with 1 mol / L NaOH solution; Transfer the obtained reaction solution to a hydrothermal reaction kettle, heat it in an oven at 120 °C for 6 h, perform centrifugation after the reaction, wash it 8 times alternately with distilled water and ethanol, and finally place the prepared Ni(OH) 2 in a vacuum and dry it at 70 °C for 18 h to obtain solid Ni(OH) 2 ; Step 3: Place 1.1 g of Ni(OH) 2 and 0.013 g of NaFeS 2 in centrifuge tubes filled with distilled water respectively, ultrasonically homogenize them, then pour the solutions into a beaker in sequence and stir for 10 min, and adjust the pH to 7 with 1 mol / L NaOH solution; Transfer the obtained reaction system to a hydrothermal reaction kettle, heat it in an oven at 120 °C for 5 h, perform centrifugation after the reaction, wash it 8 times alternately with distilled water and ethanol, and finally place the prepared Ni(OH) 2 / NaFeS 2 in a vacuum, and then dry it at 70 °C for 18 h to obtain the composite material for catalytic algae removal.

[0075] Example 6 Example 2 is different from Example 1 in that the reaction conditions in Step 3 are different.

[0076] Step 1: Add 40 mM Fe(NO 3 ) 3 ·9H 2 O and 120 mM Na 2 S·9H 2 O to distilled water, dissolve at 100 °C for 10 min, then continue stirring at 60 °C for 30 min to obtain a mixed solution. Add 2 g of NaOH to the mixed solution and adjust the pH to 7; Transfer the adjusted solution to a hydrothermal reaction kettle and place it in an oven at 180 °C for 24 hours; subsequently, cool to room temperature, wash the obtained product several times with distilled water and ethanol, and then dry it at 80 °C to form solid NaFeS 2 ; Step 2: Add 0.526 g of NiSO 4 ·6H 2 O and 1.132 g of FeSO 4 ·7H 2 O to distilled water, stir for 10 min, and adjust the pH to 7 with 1 mol / L NaOH solution; Transfer the obtained reaction solution to a hydrothermal reaction kettle, heat it in an oven at 120 °C for 6 h, perform centrifugation after the reaction ends, wash it alternately 8 times with distilled water and ethanol, and finally place the prepared Ni(OH) 2 in a vacuum and dry it at 70 °C for 18 h to obtain solid Ni(OH) 2 ; Step 3: Place 1.1 g of Ni(OH) 2 and 0.013 g of NaFeS 2 in centrifuge tubes filled with distilled water respectively, ultrasonically homogenize them, then pour the solutions into a beaker in sequence and stir for 10 min, and adjust the pH to 7 with 1 mol / L NaOH solution; Transfer the obtained reaction system to a hydrothermal reaction kettle, heat it in an oven at 120 °C for 5 h, perform centrifugation after the reaction ends, wash it alternately 8 times with distilled water and ethanol, and finally place the prepared Ni(OH) 2 / NaFeS 2 in a vacuum, and then dry it at 70 °C for 18 h to obtain the composite material for catalytic algae removal.

[0077] Comparative Example Comparative Example 1 Step 1: Weigh 0.526 g of NiSO 4 ·6H 2 O and place it in a centrifuge tube filled with 2 mL of distilled water for ultrasonic homogenization. 1.112 g of FeSO4 ·7H 2 O was placed in a centrifuge tube containing 4 mL of distilled water and sonicated evenly; Step 2: The solutions in the two centrifuge tubes were poured into a beaker in sequence for stirring, and the pH was adjusted to 7 with 1 mol / L NaOH solution (tested with a wide-range pH test paper of 1-14) to obtain a dark green mixed solution, which was loaded into a hydrothermal reaction kettle and heated in an oven at 120 °C for 6 h. After the reaction, centrifugation, washing, and drying treatments were carried out in sequence to obtain Ni(OH) 2 .

[0078] Comparative Example 2 Step 1: 40 mM Fe(NO 3 ) 3 ·9H 2 O and 120 mM Na 2 S·9H 2 O were added to distilled water, sonicated evenly at 100 °C for 10 minutes, and then continuously stirred at 60 °C for 30 minutes to obtain a mixed solution; Step 2: 2 g of NaOH was added to the mixed solution to adjust the pH to 7. The adjusted solution was transferred to a hydrothermal reaction kettle and placed in an oven at 180 °C for 24 hours. Subsequently, it was cooled to room temperature, washed several times with ethanol and acetone, and then dried at 80 °C for 18 h to form solid NaFeS 2 .

[0079] Based on Comparative Example 1 and Comparative Example 2, the spectral absorption ranges of Ni(OH) 2 / NaFeS 2、 Ni(OH) 2 and NaFeS 2 prepared in Example 1, Comparative Example 1 and Comparative Example 2 were investigated.

[0080] Referring to Figure 5 , Figure 5 is the ultraviolet diffuse reflection spectrogram of the nanomaterials prepared in Example 1, Comparative Example 1 and Comparative Example 2 of this application, Figure 5 in which "1" is NiFS, "2" is Ni(OH) 2 , "3" is NaFeS 2 . Figure 5 It shows that the optical absorption of NaFeS 2 and Ni(OH) 2 covers the entire visible spectrum, so it can be obtained that the visible light absorption range of Ni(OH) 2 / NaFeS 2 prepared in Example 1 of this application covers the entire visible spectrum, and a large absorption tail peak appears, indicating that Ni(OH) 2 / NaFeS2 As a composite material for catalytic algae removal, it can utilize sufficient visible light for catalytic algae removal.

[0081] Performance verification experiment This experiment was used to verify the removal performance of Ni(OH) 2 / NaFeS 2 , Ni(OH) 2 and NaFeS 2 against Microcystis aeruginosa.

[0082] I. Photocatalytic activity evaluation: The experiment on photocatalytic removal of Microcystis aeruginosa and synchronous degradation of MC-LR was mainly carried out in a photoreaction device (refer to Figure 6 ), Figure 6 which is a schematic diagram of the photocatalytic experiment device and experimental process in the examples of this application.

[0083] During the photocatalytic reaction process, a 300W xenon lamp equipped with a 420nm wavelength filter was used as the light source. The position of the light source was adjusted, and the light intensity was measured to be 36.7mW / cm 2 . Then a certain amount of photocatalyst and PMS were dispersed in 100 mL of algae suspension with OD 680 =0.2.

[0084] The entire experiment on photocatalytic inactivation of Microcystis aeruginosa was carried out for 5h. 10 mL of the reaction solution was taken every 1h to measure the content of chlorophyll a to evaluate the removal effect of Ni(OH) 2 / NaFeS 2 (hereinafter referred to as the NiFS / PMS system) against Microcystis aeruginosa.

[0085] II. Continuous degradation experiment: After the first reaction was completed, the material was recovered by suction filtration and re-added to the reactor for the second algae removal experiment. Except for the material, the remaining reaction conditions were the same as those in the first time; after the second reaction was completed, the above steps were repeated, and a total of five algae removal experiments were carried out.

[0086] The experimental results showed that: under the irradiation of visible light (λ>400nm) with a light intensity of 36.7mW / cm 2 , with a catalyst dosage of 0.1g, a PMS dosage of 0.05 mM, an initial concentration of Microcystis aeruginosa of OD 680 =0.2, and an initial temperature of room temperature, the algae removal efficiency of the NiFS / PMS system was as high as 98% in 5h.

[0087] Figure 7 NaFeS prepared in Comparative Example 1 and Comparative Example 2 of this application 2Photocatalytic Nanomaterials and Ni(OH) 2 Performance comparison chart of visible-light photocatalytic removal of Microcystis aeruginosa by photocatalysts, Figure 7 in which "1" is NaFeS 2 、"2" is NiFe 2 O 4 、"3" is Ni(OH) 2 / NaFeS 2 . It can be seen that due to the general algae removal effect of the NaFeS 2 / PMS system and the Ni(OH) 2 / PMS system, the removal rate within 5 h is only about 50%. Under 5 h of visible-light irradiation, the NiFS / PMS system has an algae removal efficiency as high as 98%. Therefore, it is proved that the algae removal material obtained by compounding NaFeS 2 and Ni(OH) 2 has better performance.

[0088] Figure 8 This is the chart of stable photocatalytic performance of the Ni(OH) 2 / NaFeS 2 composite material prepared in Example 1 of this application. Figure 8 In the chart, each algae removal experiment is carried out every 5 h. After the first reaction is completed, the petri dish containing the photocatalyst is dried at 60 °C for 0.5 h, and then put into the reactor again for the next algae removal reaction. Except for the material, the remaining reaction conditions are the same as those in the first time; after the second reaction is completed, repeat the above steps to carry out the third algae removal experiment. In five consecutive algae removal experiments, the algae removal efficiency is above 88%, which indicates that the photocatalytic activity of the Ni(OH) 2 / NaFeS 2 composite material still remains good after five cycles and can be recycled.

[0089] Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same and similar parts among the embodiments, reference can be made to each other.

[0090] Although the preferred embodiments of the embodiments of this application have been described, once those skilled in the art know the basic creative concepts, additional changes and modifications can be made to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the embodiments of this application.

[0091] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or terminal device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or terminal device comprising the element.

[0092] The above provides a detailed introduction to a catalytic alga-removing material and its preparation method provided by the present application. Specific examples are used in this text to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A method for preparing a catalytic algae removal material, characterized in that: The preparation method comprises: Add Ni(OH)2 and NaFeS2 in a mass ratio of 1:(9~11) into distilled water and stir for 8~12 minutes. Adjust the pH to 6.5~7.

5. Place the resulting reaction system in a water bath at 110~130°C and heat for 5~7 hours to obtain Ni(OH)2 / NaFeS2. Centrifuge, wash and dry the obtained Ni(OH)2 / NaFeS2 to obtain a catalytic algae removal material.

2. The method for preparing the catalytic algae removal material according to claim 1, characterized in that: Adjusting the pH to 6.5-7.5 includes: adding a NaOH solution with a concentration of 0.8-1.2 mol / L into the stirred system to adjust the pH to 6.5-7.

5.

3. The method for preparing the catalytic algae removal material according to claim 1, characterized in that: The drying comprises: placing the Ni(OH)2 / NaFeS2 under vacuum and drying at 60-80°C for 12-24h.

4. The method for preparing the catalytic algae removal material according to claim 1, characterized in that: The cleaning comprises: washing with distilled water and ethanol alternately for 6 to 10 times.

5. The method for preparing the catalytic algae removal material according to claim 1, characterized in that: The temperature of the water bath environment is between 115 and 125°C.

6. The method for preparing the catalytic algae removal material according to claim 1, characterized in that: The preparation method of the NaFeS2 comprises: Fe(NO3)3·9H2O and Na2S·9H2O were added into distilled water, dissolved at 90~110℃ for 8~12min, and then stirred at 50~70℃ for 25~35min to prepare a mixed solution; Add NaOH to the mixed solution, adjust the pH to 6.5-7.5, and heat in a water bath at 170-190° C. for 24-26 hours to obtain the NaFeS 2 .

7. The method for preparing the catalytic algae removal material according to claim 6, characterized in that: The molar ratio of Fe(NO3)3·9H2O to Na2S·9H2O is 1:(2~4).

8. The method for preparing the catalytic algae removal material according to claim 1, characterized in that: The preparation method of Ni(OH)2 comprises: NiSO4·6H2O and FeSO4·7H2O in a mass ratio of (0.5-0.6):1 are mixed and stirred for 8-12 minutes, the pH is adjusted to 6.5-7.5, and the adjusted system is placed in a water bath environment at 110-130° C. and heated for 5-6 hours, and the obtained product is the Ni(OH)2.

9. A catalytic algaecidal material prepared by the method for preparing a catalytic algaecidal material according to any one of claims 1 to 8.

10. Use of a catalytic algaecide material prepared by the method for preparing a catalytic algaecide material according to any one of claims 1 to 8, characterized in that: The catalytic algae removal material photocatalytically removes algae in sewage under the action of visible light.

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