Ternary magnetic composite nano material and preparation method and application thereof
阅读说明：本技术 一种三元磁性复合纳米材料及其制备方法与应用 (Ternary magnetic composite nano material and preparation method and application thereof ) 是由 杨磊 李志洋 艾伟 钟丹 于 2020-12-24 设计创作，主要内容包括：本申请提供了一种三元磁性复合纳米材料,属于光催化纳米复合材料技术领域与污染物处理领域。本申请的三元磁性复合纳米材料为层状的C-3N-4-Cg/ZnO/CNFe,层状的C-3N-4-Cg/ZnO/CNFe由片状C-3N-4-Cg、片状的ZnO和负载在ZnO与C-3N-4-Cg之间的CNFe组成；其中,所述C-3N-4-Cg包括g-C-3N-4和g-C-3N-4边缘处的石墨烯；所述CNFe为包覆铁的碳纳米管。本申请在g-C-3N-4中引入了石墨烯、ZnO和CNFe,扩展了g-C-3N-4的光吸收范围,由原来的可见光波段扩展至全可见光。(The application provides a ternary magnetic composite nano material, and belongs to the technical field of photocatalytic nano composite materials and the field of pollutant treatment. The ternary magnetic composite nano material is C with a layer shape 3 N 4 Cg/ZnO/CNFe, layered C 3 N 4 Cg/ZnO/CNFe in flake form 3 N 4 Cg, sheet-like ZnO and ZnO and C loaded 3 N 4 CNFe composition between Cg; wherein, the C 3 N 4 Cg includes g-C 3 N 4 And g-C 3 N 4 Graphene at the edges; the CNFe is a carbon nano tube coated with iron. This application is in g-C 3 N 4 Graphene, ZnO and CNFe are introduced, and g-C is expanded 3 N 4 The light absorption range of (1) is extended from the original visible light band to the full visible light.)
1. The ternary magnetic composite nano material is characterized in that the ternary magnetic composite nano material is layered C3N4Cg/ZnO/CNFe, said layered C3N4Cg/ZnO/CNFe in flake form3N4Cg, flaky ZnO and supported on ZnO and C3N4CNFe composition between Cg;
wherein, the C3N4Cg includes g-C3N4And g-C3N4Graphene at the edges;
the CNFe is a carbon nano tube coated with iron.
2. The ternary magnetic composite nanomaterial of claim 1, wherein the C is3N4-Cg, the mass ratio of CNFe to ZnO being 1: (0.05-0.3): (0.2 to 1).
3. A method for preparing a ternary magnetic composite nanomaterial, wherein the method is used for preparing the ternary magnetic composite nanomaterial of claim 1, and the method comprises the following steps:
step 1, calcining carbon-nitrogen source in two steps to prepare C3N4-Cg；
Step 2, calcining a zinc source to prepare ZnO;
step 3, mixing a carbon nitrogen source and an iron source, and calcining to prepare CNFe;
step 4, adopting an ultrasonic dipping method to mix C3N4And compounding the Cg, the ZnO and the CNFe to prepare the ternary magnetic composite nano material.
4. The method for preparing a ternary magnetic composite nanomaterial of claim 3, wherein in the step 1, the C is prepared3N4The specific process of-Cg is:
step 1-1, calcining carbon-nitrogen source at 500-600 ℃ for 3-5 h to prepare g-C3N4；
Step 1-2, g-C is prepared3N4Calcining the mixture in nitrogen for 3 to 5 hours at the temperature of between 600 and 700 ℃ to prepare the carbon dioxide3N4-Cg；
Wherein in the step 1-1, the temperature rise rate during calcination is 2 ℃/min to 10 ℃/min;
in the step 1-2, the temperature rise rate during calcination is 5 ℃/min to 15 ℃/min.
5. The method for preparing the ternary magnetic composite nanomaterial of claim 3, wherein in the step 2, the zinc source comprises: one or more of zinc acetate, zinc nitrate, zinc hydroxide and zinc sulfate;
the calcination is carried out by heating to 200-500 ℃ at 2-10 ℃/min for 2-4 h.
6. The method for preparing the ternary magnetic composite nanomaterial of claim 3, wherein in the step 3, the specific process for preparing the CNFe is as follows:
step 3-1, dissolving a carbon nitrogen source and ferric salt in a solvent, ultrasonically stirring, and drying to obtain a mixture A;
step 3-2, calcining the mixture A under nitrogen to obtain a product B;
and 3-3, carrying out acid washing on the product B, then washing with water, then carrying out centrifugal washing to obtain a precipitate, and drying to obtain the CNFe.
7. The method for preparing the ternary magnetic composite nanomaterial according to claim 6, wherein in the step 3-1, the mass ratio of the carbon-nitrogen source to the iron salt is 1: (1-1.5);
the iron salts include: one or more of ferric sulfate, ferric chloride, and ferric nitrate;
the ultrasonic time is 1-2 h;
the stirring is carried out for 10 to 20 hours at 400 to 1200rpm by magnetic stirring;
in the step 3-2, the calcination is carried out for 1 h-2 h by heating to 700 ℃ -900 ℃ at the speed of 2 ℃/min-10 ℃/min;
in the step 3-3, the centrifugal washing is carried out for 6-10 times at the rotating speed of 8000-10000 rpm;
the drying is carried out for 10 to 20 hours at the temperature of between 40 and 80 ℃.
8. The method for preparing the ternary magnetic composite nanomaterial of claim 3, wherein in the step 1, the carbon-nitrogen source comprises a nitrogen-containing organic substance with a carbon-nitrogen ratio of (1-3): 3-1, and the nitrogen-containing organic substance comprises: one or more of cyanamide, dicyandiamide, melamine and urea;
in the step 3, the carbon-nitrogen source comprises nitrogen-containing organic matters with a carbon-nitrogen ratio of (1-3) to (3-1), and the nitrogen-containing organic matters comprise: one or more of cyanamide, dicyandiamide, melamine and urea.
9. The method for preparing the ternary magnetic composite nanomaterial of claim 3, wherein in the step 4, the specific method for preparing the ternary magnetic composite nanomaterial comprises the following steps:
c prepared in the step 13N4Adding Cg, ZnO prepared in the step 2 and CNFe prepared in the step 3 into a dispersing agent, and performing ultrasonic dispersion uniformly; then stirredStirring, centrifugally washing to obtain a precipitate, and drying to obtain the ternary magnetic composite nano material;
wherein, the C3N4-Cg, the ZnO and the CNFe at a mass ratio of 1: (0.2-1): (0.05 to 0.3);
the dispersant comprises alcohols, including: one or more of methanol, ethanol, and isopropanol;
the time of the sub-ultrasonic dispersion is 1-4 h;
the stirring is carried out for 1 to 3 hours under the condition of 400 to 1200rpm by magnetic stirring;
the centrifugal washing is carried out for 6-10 times at the rotating speed of 8000-10000 rpm;
the drying is carried out for 5 to 10 hours at the temperature of between 40 and 80 ℃.
10. Use of the ternary magnetic composite nanomaterial of claim 1 or 2 in degrading organic pollutants in a body of water, the organic pollutants comprising: one or more of bisphenol a, phenol, caffeine, and an organic dye;
the ternary magnetic composite nano material activates persulfate to degrade bisphenol A in a water body.
Technical Field
The invention relates to the technical field of photocatalytic nano composite materials and the field of pollutant treatment, in particular to a ternary magnetic composite nano material and a preparation method and application thereof.
Background
Bisphenol A (2, 2-bis (4-hydroxyphenyl) propane, BPA) is an important high-yield chemical raw material synthesized artificially, is usually used as a raw material and an intermediate for producing epoxy resin and polycarbonate, and is an important material for oxidation resistance and stabilization treatment in surgical repair, and is widely used in food packaging and inner wall coatings of containers. It is difficult to degrade in the environment, has a significant lipophilicity and is readily enriched in organisms, and can be transported across populations through the food chain. Epidemiological studies have also shown that BPA has low dose effects and acts on the body in the form of hormones, thereby affecting the normal endocrine function of the organism and human body as well as the development of the reproductive, embryonic and nervous systems, with potential risks to human health and ecosystem safety.
At present, the methods for removing bisphenol A mainly comprise physical adsorption, chemical degradation, microbial degradation and the like. Among them, the photocatalytic method is one of the main chemical degradation methods currently used. Graphite phase carbon nitride (g-C)3N4) The carbon nitride structure is the most stable carbon nitride structure at room temperature, can absorb visible light as a visible light catalyst without metal components, has good thermal stability and light stability, has good visible light absorption capacity and higher conduction band position, and is a hotspot in the research of the field of photocatalysis at present. But g-C3N4The light absorption range of the compound is narrow, and the compound has photochemical activity only in the range of 440-475nm visible light wave band and can not absorb light energyThe utilization rate is very low; high recombination rate of photo-generated electron-hole pairs, resulting in g-C3N4The degradation efficiency is not high.
Disclosure of Invention
The application provides a ternary magnetic composite nano material, a preparation method and application thereof, aiming at solving the problem of g-C3N4Has a narrow light absorption range and g-C3N4The problem that photo-generated electrons and holes are easy to recombine is solved, and the problem that the catalytic efficiency of the bisphenol A is low because the existing catalyst can only absorb partial visible light is solved.
In a first aspect, the present application discloses a ternary magnetic composite nanomaterial that is a layered C3N4Cg/ZnO/CNFe, layered C3N4Cg/ZnO/CNFe in flake form3N4Cg, flaky ZnO and supported on ZnO and C3N4CNFe composition between Cg; wherein, C3N4Cg includes g-C3N4And g-C3N4Graphene at the edges; CNFe is an iron-coated carbon nanotube.
Preferably, C in the ternary magnetic composite nano material3N4-the mass ratio of Cg, CNFe and ZnO is 1: (0.05-0.3): (0.2 to 1).
In a second aspect, the present application provides a method for preparing a ternary magnetic composite nanomaterial, for preparing the ternary magnetic composite nanomaterial of the first aspect, the method comprises the following steps:
step 1, calcining carbon-nitrogen source in two steps to prepare C3N4-Cg；
Step 2, calcining a zinc source to prepare ZnO;
step 3, mixing a carbon nitrogen source and an iron source, and calcining to prepare CNFe;
step 4, adopting an ultrasonic dipping method to mix C3N4And compounding the Cg, the ZnO and the CNFe to prepare the ternary magnetic composite nano material.
Preferably, in step 1, preparation C3N4The specific process of-Cg is:
step 1-1Calcining carbon-nitrogen source at 500-600 deg.c for 3-5 hr to obtain g-C3N4；
Step 1-2, g-C is prepared3N4Calcining the mixture in nitrogen for 3 to 5 hours at the temperature of between 600 and 700 ℃ to prepare the carbon dioxide3N4-Cg。
Preferably, in the step 1-1, the heating rate during the calcination is 2 ℃/min to 10 ℃/min;
in the step 1-2, the temperature rise rate during calcination is 5 ℃/min to 15 ℃/min.
Preferably, in step 2, the zinc source comprises: one or more of zinc acetate, zinc nitrate, zinc hydroxide and zinc sulfate. More preferably, in step 2, the zinc source is zinc hydroxide.
Preferably, in the step 2, the calcination is carried out by heating to 200-500 ℃ at 2-10 ℃/min for 2-4 h.
Preferably, in step 3, the specific process for preparing CNFe is as follows:
step 3-1, dissolving a carbon nitrogen source and ferric salt in a solvent, ultrasonically stirring, and drying to obtain a mixture A;
step 3-2, calcining the mixture A under nitrogen to obtain a product B;
and 3-3, carrying out acid washing on the product B, then washing with water, then carrying out centrifugal washing to obtain a precipitate, and drying to obtain the CNFe.
Preferably, in step 3-1, the mass ratio of the carbon nitrogen source to the iron salt is 1: (1-1.5).
Preferably, in step 3-1, the iron salt comprises: one or more of ferric sulfate, ferric chloride and ferric nitrate.
Preferably, in the step 3-1, the time of ultrasonic treatment is 1 h-2 h.
Preferably, in step 3-1, the stirring is performed by magnetic stirring at 400rpm to 1200rpm for 10h to 20 h.
Preferably, in the step 3-2, the calcination is carried out by heating to 700-900 ℃ at 2-10 ℃/min for 1-2 h.
Preferably, in step 3-3, the centrifugal washing is carried out 6-10 times at a rotation speed of 8000-10000 rpm.
Preferably, in the step 3-1, the drying is performed at 40-80 ℃ for 10-20 h.
Preferably, in step 1, the carbon-nitrogen source comprises nitrogen-containing organic matters with the carbon-nitrogen ratio of (1-3): 3-1; more preferably, in step 1, the nitrogen-containing organic compound comprises: one or more of cyanamide, dicyandiamide, melamine and urea; more preferably, the nitrogen-containing organic substance is dicyandiamide.
Preferably, in step 3, the carbon-nitrogen source comprises nitrogen-containing organic matters with the carbon-nitrogen ratio of (1-3): 3-1; more preferably, in step 3, the nitrogen-containing organic compound comprises: one or more of cyanamide, dicyandiamide, melamine and urea; more preferably, the nitrogen-containing organic substance is dicyandiamide. Preferably, in step 4, the specific method for preparing the ternary magnetic composite nanomaterial comprises:
c prepared in the step 13N4Adding Cg, ZnO prepared in the step 2 and CNFe prepared in the step 3 into a dispersing agent, and performing ultrasonic dispersion uniformly; and then stirring, centrifuging and washing to obtain a precipitate, and drying to obtain the ternary magnetic composite nano material.
Preferably, in step 4, C3N4The mass ratio of Cg, ZnO and CNFe is 1: (0.2-1): (0.05-0.3).
Preferably, in step 4, the dispersant comprises an alcohol.
More preferably, in step 4, the alcohols include: one or more of methanol, ethanol and isopropanol.
More preferably, in step 4, the alcohol is isopropanol.
Preferably, in the step 4, the time for ultrasonic dispersion is 1 h-4 h.
Preferably, in step 4, the stirring is performed by magnetic stirring at 400rpm to 1200rpm for 1h to 3 h.
Preferably, in the step 4, the centrifugal washing is carried out 6-10 times at 8000-10000 rpm.
Preferably, in the step 4, the drying is carried out for 5 to 10 hours at the temperature of between 40 and 80 ℃.
In a third aspect, the application provides an application of the ternary magnetic composite nanomaterial of the first aspect in degrading organic pollutants in a water body.
Preferably, the organic contaminants include: one or more of bisphenol A, phenol, caffeine, and an organic dye.
More preferably, the organic contaminant is bisphenol a.
Preferably, the ternary magnetic composite nanomaterial activates persulfate to degrade bisphenol A in a water body.
Compared with the prior art, the method has the following advantages:
the application provides a ternary magnetic composite nano material which is a layered C3N4Cg/ZnO/CNFe, layered C3N4Cg/ZnO/CNFe in flake form3N4Cg, flaky ZnO and supported on ZnO and C3N4CNFe composition between Cg; wherein, C3N4Cg includes g-C3N4And g-C3N4Graphene at the edges; CNFe is an iron-coated carbon nanotube. On the one hand, since in g-C3N4Graphene, ZnO and CNFe are introduced, and g-C is expanded3N4The light absorption range is expanded from the original visible light waveband of 440-475nm to the full visible light waveband of 400-760nm, so that the light energy can be well utilized. On the other hand, C3N4Presence of graphene in Cg, of C3N4Cg has an intermediate energy gap between its valence and conduction bands, from C3N4Excitation of the Cg valence band to C3N4The photo-generated electrons with-Cg intermediate energy gap can reduce oxygen to generate superoxide radical, and increase C3N4-photocatalytic efficiency of Cg; when C is present3N4When Cg is compounded with ZnO and CNFe, under the irradiation of visible light, C3N4The conduction band of-Cg is excited simultaneously with the CNFe conduction band and injects electrons into the ZnO conduction band, and at C3N4The holes are left in-Cg and CNFe. Since in ZnO and C3N4Heterogeneous charge transfer occurs at the interface of-Cg and CNFe, and C is increased3N4The electron-hole separation efficiency of-Cg/ZnO/CNFe promotes the subsequent oxidation-reduction reaction, realizes higher charge transfer, and ensures that the oxide-doped silicon carbide hasBetter photocatalytic performance. In addition, the ternary magnetic composite nano material has magnetism due to the introduction of iron, and facilitates the recycling of the photocatalyst.
Drawings
FIG. 1 is an SEM image of example 1 of the present invention: (a) (b) is layer C under different magnification3N4SEM image of Cg/ZnO/CNFe; (c) SEM image of CNFe;
FIG. 2 shows a graph C in example 1 of the present invention3N4-a TEM image of Cg;
FIG. 3 shows ZnO and g-C in example 1 of the present invention3N4、C3N4Cg/ZnO/CNFe and comparative example C3N4-a uv diffuse reflectance spectrum of Cg/ZnO;
FIG. 4 shows a graph C in example 1 of the present invention3N4-Cg、CNFe、C3N4Cg/ZnO/CNFe and comparative example C3N4-Cg/ZnO fourier ir spectrum;
FIG. 5 shows pure light, g-C in Experimental example 1 of the present invention3N4、C3N4-Cg、C3N4Cg/ZnO/CNFe and C in comparative example3N4A performance contrast diagram of visible photocatalytic degradation of Cg/ZnO for BPA;
FIG. 6 is a graph comparing the performance of the present invention in Experimental example 1, example 2, example 3 and comparative example for visible photocatalytic degradation of BPA;
FIG. 7 shows a graph C in Experimental example 1 of the present invention3N4-Cg/ZnO/CNFe reusability experiment of visible photocatalytic degradation of BPA.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with examples are described in detail below. It is to be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the present invention. Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the spirit and scope of this invention. Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.
In a first aspect, the present application provides a ternary magnetic composite nanomaterial comprising layered C3N4Cg/ZnO/CNFe, said C3N4Cg/ZnO/CNFe is formed by mixing the components in a mass ratio of 1: (0.2-1): (0.05-0.3) C3N4Cg, ZnO and CNFe.
Due to the fact that in g-C3N4Graphene, ZnO and CNFe are introduced, and g-C is expanded3N4The light absorption range of the light source is expanded from the original visible light wave band of 440nm-475nm to the full visible light of 400nm-760nm, so that C is3N4the/ZnO/CNFe can well utilize solar energy.
In a second aspect, the present application provides a method for preparing the ternary magnetic composite nanomaterial of the first aspect, the method comprising the steps of,
step 1, calcining carbon-nitrogen source in two steps to prepare C3N4-Cg；
Preparation C3N4The specific steps of-Cg are:
step 1-1, putting a carbon-nitrogen source into a crucible for calcination, cooling to room temperature, and grinding to obtain g-C3N4；
Step 1-2, adding g-C3N4Calcining under the protection of inert gas to obtain C3N4-Cg。
Preferably, in step 1-1, the carbon-nitrogen source is selected from the group consisting of carbon-nitrogen ratio of 1: 2 (molecular weight less than 10000) such as cyanamide, dicyanamide, melamine, urea, and more preferably, the carbon-nitrogen source is dicyanamide.
Preferably, in the step 1-1, the calcination temperature of the carbon-nitrogen source is 500-600 ℃, and the calcination time is 3-5 h.
More preferably, in the step 1-1, the temperature is raised to 500-600 ℃ at a rate of 2-10 ℃/min.
Preferably, in step 1-2, g-C3N4The calcining temperature in inert gas is 600-700 ℃, and the calcining time is 3-5h。
More preferably, in the step 1-2, the temperature is raised to 600-700 ℃ at a temperature rise rate of 5-15 ℃/min.
And 2, calcining the zinc source to obtain the ZnO.
Preferably, in step 2, the zinc source is selected from zinc acetate, zinc nitrate, zinc sulfate, zinc carbonate, zinc hydroxide, preferably zinc hydroxide.
Preferably, in the step 2, the calcining temperature is 200-500 ℃ and the calcining time is 2-4 h.
More preferably, in step 2, the temperature is raised to 200-500 ℃ at a rate of 2-10 ℃/min.
Step 3, dissolving a carbon nitrogen source and ferric salt in an organic solvent, and drying after ultrasonic treatment to obtain a mixture; the mixture was calcined in an inert gas to obtain CNFe.
The specific steps for preparing CNFe are as follows:
step 3-1, dissolving a carbon nitrogen source and ferric salt in an organic solvent, ultrasonically stirring, and drying to obtain a mixture A;
step 3-2, calcining the mixture A under the protection of inert gas to obtain a product B;
and 3-3, firstly, carrying out acid washing on the product B, then, carrying out water washing, then, carrying out centrifugal washing to obtain a precipitate, and drying to obtain the CNFe.
The first acid washing in the washing process is to remove iron on the surface of the carbon nano tube, and the carbon nano tube is washed to be neutral by water because the carbon nano tube is acidic after being washed by water.
Preferably, in step 3-1, the carbon-nitrogen source is selected from the group consisting of carbon-nitrogen ratio (1-3): (3-1) a small molecular weight nitrogen-containing organic substance (nitrogen-containing organic substance having a molecular weight of 10000 or less), such as cyanamide, dicyanamide, melamine, urea, and more preferably, the carbon-nitrogen source is dicyanamide.
Preferably, in the step 3-1, the ferric salt is one or more of ferric sulfate, ferric chloride and ferric nitrate; more preferably, the iron salt is ferric chloride.
Preferably, in step 3-1, the mass ratio of the carbon-nitrogen source to the iron salt is 1: (1 to 1.5) and if the amount exceeds the above range, the iron-coated carbon nanotube cannot be formed.
Preferably, in the step 3-1, the ultrasonic time is 1-2h, and the stirring is magnetic stirring at 400-1200 rpm for 10-20 h.
Preferably, in the step 3-2, the calcination is performed for 1-2 hours in a nitrogen atmosphere at a temperature of 700-900 ℃ at a speed of 2-10 ℃/min. If the temperature is lower than this temperature during the calcination, the iron nanotubes are not burned, and if the temperature is higher than this temperature, the iron nanotubes are easily burned into ash-like substances.
Further, in the step 3-3, the CNFe precipitate is obtained by centrifugal washing for 6-10 times at 8000-10000 rpm and is dried for 10-20 h at 40-80 ℃.
In step 3, the key point of the reaction of the carbon nitrogen source and the ferric salt to generate the iron nano tube is temperature control, and before the temperature is 600 ℃, the carbon nitrogen source and the iron mainly form thicker g-C3N4And coating and loading a layer of amorphous iron species; as the temperature is gradually increased, the amorphous iron species are converted to iron oxide, which is then reduced to iron element, which reacts with carbon nitride, and g-C3N4A graphite layer is gradually formed, and when the temperature is further raised, the graphite layer starts to grow into carbon nanotubes, and at the same time, due to the accumulation of compressive stress and the increase of surface tension, hydrothermal cementite particles axially move in the graphite layer, thereby forming iron-coated carbon nanotubes.
Step 4, adding C3N4Dispersing the-Cg, the ZnO and the CNFe in a solvent, and compounding by adopting an ultrasonic impregnation method to obtain the ternary magnetic composite nano material ZnO/CNFe/C3N4-Cg。
Preparation of ternary magnetic composite nano material ZnO/CNFe/C3N4The specific steps of Cg are;
step 4-1, the C prepared in the step 13N4Adding Cg, ZnO prepared in the step 2 and CNFe prepared in the step 3 into a dispersing agent to be uniformly dispersed to obtain a mixed solution;
step 4-2, continuously stirring the mixed solution, centrifugally washing to obtain a precipitate, and drying to obtain the photocatalyst C3N4-Cg/ZnO/CNFe。
Preferably, in step 4-1, C3N4The relative mass ratio of-Cg, ZnO, CNFe is 1: (0.2-1): (0.05-0.3), if the ZnO is too much in the compounding process, the carbon proportion and the absorbance of the ternary magnetic composite nano material are reduced, and the degradation result is influenced; if the content of the iron nano tube is higher, the content of iron is increased, Fenton-like reaction is easy to occur in the photocatalysis process, and photocatalysis is not easy.
Preferably, in step 4-1, the dispersing solvent is an alcohol, such as methanol, ethanol, isopropanol, and more preferably, the dispersing solvent is isopropanol.
Preferably, in the step 4-1, the time for ultrasonic dispersion is 1-4 h.
Preferably, in the step 4-2, the stirring is performed by magnetic stirring for 1-3 hours at 400-1200 rpm.
Preferably, in the step 4-2, the precipitate is obtained by centrifugal washing for 6-10 times at 8000-10000 rpm, and is dried for 5-10 h at 40-80 ℃.
In a third aspect, the invention also provides a ternary magnetic composite nano material C of the first aspect3N4Application of Cg/ZnO/CNFe in degrading organic pollutants in water.
Preferably, the organic contaminants include one or more of bisphenol a, phenol, caffeine, and organic dyes.
More preferably, the organic contaminant is bisphenol a.
C3N4When Cg/ZnO/CNFe is used as a catalyst to degrade organic pollutants in water, the organic pollutants are exposed to light at C3N4Heterogeneous charge transfer can occur at the interface of-Cg with ZnO, CNFe, i.e. C3N4The conduction band of-Cg is excited simultaneously with the CNFe conduction band and injects electrons into the ZnO conduction band, and at C3N4Cg and CNFe will leave holes, electrons on the conduction band of ZnO and C3N4The holes in the valence bands of-Cg and CNFe undergo reduction and oxidation reactions respectively, so that C is reduced3N4The electron-hole recombination rate of-Cg/ZnO/CNFe promotes the subsequent oxidation-reduction reaction. C3N4The holes in Cg, CNFe can react with water, the hydroxyl radical in water to generate hydroxyl radical (. OH)The electrons in ZnO react with oxygen dissolved in water to generate superoxide radical (. O)2 -) Hydroxyl radical (. OH) and H2O2Superoxide radical (. O)2 -) Hydroxyl radical (. OH) and H2O2These active substances can promote the decomposition of organic substances in the water body.
Preferably, the ternary magnetic composite nanomaterial activates persulfate to degrade bisphenol A in a water body.
By C3N4When bisphenol A in water is degraded by Cg/ZnO/CNFe, PMS (potassium hydrogen persulfate) is added into the sewage containing bisphenol A, and PMS can generate sulfate radical (SO)4 -·)，SO4 -Has a high oxidation-reduction potential and can oxidize most organic substances. In the degradation process C3N4Superoxide radical (. O) produced by Cg/ZnO2 -) OH, H2O2With sulfate radicals (SO)4 -And.) act together to degrade bisphenol A in the water.
The above-described preferred conditions may be combined with each other to obtain a specific embodiment, in accordance with common knowledge in the art.
Example 1
Step 1: placing 5g of dicyandiamide in an alumina crucible with a cover, calcining for 3h at 550 ℃ in a muffle furnace at the heating rate of 5 ℃/min, and finally grinding and collecting the obtained powder to obtain g-C3N4G to C3N4Heating to 650 ℃ at a speed of 10 ℃/min in nitrogen atmosphere, calcining for 3.5h to obtain the carbon-carbon composite material C3N4-Cg；
Step 2: putting zinc hydroxide into an alumina crucible with a cover, heating to 200 ℃ in a muffle furnace at the heating rate of 10 ℃/min, and calcining for 2.5 hours at the temperature to obtain nano zinc oxide;
and step 3: dicyandiamide and ferric chloride hexahydrate were mixed in a mass ratio of 1: dissolving the mixture in absolute ethyl alcohol according to the proportion of 1, performing ultrasonic treatment for 1h, stirring the mixture for 15h at room temperature, drying the mixture in an oven at 60 ℃, heating the mixture to 800 ℃ at the speed of 10 ℃/min in a nitrogen atmosphere, calcining the mixture for 1.5h to obtain a product, placing the product in 50ml of 3mol/L hydrochloric acid solution for acid washing, washing the precipitate for 6 times by using ultrapure water, and placing the precipitate in the oven at 60-80 ℃ for drying to obtain the carbon nano tube CNFe coated with iron.
And 4, step 4: 1gC is added3N4placing-Cg, 0.4g nano zinc oxide and 0.1g CNFe in 50ml isopropanol, ultrasonically dispersing for 1 hour, magnetically stirring at 600rpm for 1 hour, centrifugally washing the mixture with ultrapure water for 6 times, and drying at 60 deg.C for 20 hours to obtain C3N4Cg/ZnO/CNFe photocatalyst, noted C3N4-Cg/ZnO/CNFe-100。
Example 2
Step 1: placing 5g of dicyandiamide in an alumina crucible with a cover, calcining for 3h at 550 ℃ in a muffle furnace at the heating rate of 5 ℃/min, and finally grinding and collecting the obtained powder to obtain g-C3N4G to C3N4Heating to 650 ℃ at a speed of 10 ℃/min in nitrogen atmosphere, calcining for 3.5h to obtain the carbon-carbon composite material C3N4-Cg；
Step 2: putting zinc hydroxide into an alumina crucible with a cover, heating to 200 ℃ in a muffle furnace at the heating rate of 10 ℃/min, and calcining for 2.5 hours at the temperature to obtain nano zinc oxide;
and step 3: dicyandiamide and ferric chloride hexahydrate were mixed in a mass ratio of 1: dissolving the mixture in absolute ethyl alcohol according to the proportion of 1, performing ultrasonic treatment for 1h, stirring the mixture for 15h at room temperature, drying the mixture in an oven at the temperature of 60-80 ℃, heating the mixture to 800 ℃ at the speed of 10 ℃/min in a nitrogen atmosphere, calcining the mixture for 1.5h to obtain a product, placing the product in 50ml of 3mol/L hydrochloric acid solution for acid washing, washing the precipitate for 6 times by using ultrapure water, and placing the precipitate in the oven at the temperature of 60-80 ℃ for drying to obtain the carbon nano tube CNFe coated with iron.
And 4, step 4: 1gC is added3N4placing-Cg, 0.4g nanometer zinc oxide, 0.03g CNFe in 50ml isopropanol, ultrasonic dispersing for 1 hr, magnetically stirring at 600rpm for 1 hr, centrifugally washing the mixture with ultrapure water for 6 times, drying at 60 deg.C for 20 hr to obtain C3N4Cg/ZnO/CNFe photocatalyst, noted C3N4-Cg/ZnO/CNFe-30。
Example 3
Step 1: placing 5g of dicyandiamide in an alumina crucible with a cover, calcining for 3h at 550 ℃ in a muffle furnace at the heating rate of 5 ℃/min, and finally grinding and collecting the obtained powder to obtain g-C3N4G to C3N4Heating to 650 ℃ at a speed of 10 ℃/min in nitrogen atmosphere, calcining for 3.5h to obtain the carbon-carbon composite material C3N4-Cg；
Step 2: putting zinc hydroxide into an alumina crucible with a cover, heating to 200 ℃ in a muffle furnace at the heating rate of 10 ℃/min, and calcining for 2.5 hours at the temperature to obtain nano zinc oxide;
and step 3: dicyandiamide and ferric chloride hexahydrate were mixed in a mass ratio of 1: dissolving the mixture in absolute ethyl alcohol according to the proportion of 1, performing ultrasonic treatment for 1h, stirring the mixture for 15h at room temperature, drying the mixture in an oven at the temperature of 60-80 ℃, heating the mixture to 800 ℃ at the speed of 10 ℃/min in a nitrogen atmosphere, calcining the mixture for 1.5h to obtain a product, placing the product in 50ml of 3mol/L hydrochloric acid solution for acid washing, washing the precipitate for 6 times by using ultrapure water, and placing the precipitate in the oven at the temperature of 60-80 ℃ for drying to obtain the carbon nano tube CNFe coated with iron.
And 4, step 4: 1gC is added3N4placing-Cg, 0.4g nanometer zinc oxide, 0.05g CNFe in 50ml isopropanol, ultrasonic dispersing for 1 hr, magnetically stirring at 600rpm for 1 hr, centrifugally washing the mixture with ultrapure water for 6 times, drying at 60 deg.C for 20 hr to obtain C3N4Cg/ZnO/CNFe photocatalyst, noted C3N4-Cg/ZnO/CNFe-50。
Comparative example
Step 1: placing 5g of dicyandiamide in an alumina crucible with a cover, calcining for 3h at 550 ℃ in a muffle furnace at the heating rate of 5 ℃/min, and finally grinding and collecting the obtained powder to obtain g-C3N4G to C3N4Heating to 650 ℃ at a speed of 10 ℃/min in nitrogen atmosphere, calcining for 3.5h to obtain the carbon-carbon composite material C3N4-Cg；
Step 2: putting zinc hydroxide into an alumina crucible with a cover, heating to 200 ℃ in a muffle furnace at the heating rate of 10 ℃/min, and calcining for 2.5 hours at the temperature to obtain nano zinc oxide;
and step 3: 1gC is added3N4-Cg、Placing 0.4g nanometer zinc oxide in 50ml isopropanol, ultrasonically dispersing for 1 hr, magnetically stirring at 600rpm for 1 hr, centrifugally washing the mixture with ultrapure water for 6 times, and drying at 60 deg.C for 20 hr to obtain C3N4-Cg/ZnO photocatalyst.
In order to further illustrate that the ternary magnetic composite nano-material prepared by the method has excellent photocatalytic performance, the method is analyzed by combining a specific figure.
FIG. 1 shows CNFe and C prepared in example 13N4SEM image of Cg/ZnO/CNFe composite visible light catalytic nano material. As can be seen from the figure, C3N4Cg/ZnO/CNFe is a layered structure consisting of C in the form of platelets3N4-Cg and ZnO nanosheet material stacked on top of each other at C3N4CNFe appears between Cg and ZnO.
FIG. 2 shows a graph C in example 1 of the present invention3N4TEM image of Cg. As can be seen from the figure, C3N4Cg still has a layered structure inside, while the edges show a sufficiently inhomogeneous network, at C3N4The edge of Cg, where a 0.225nm lattice fringe corresponding to the (100) crystal plane of graphene can be observed, further evidences that graphene is generated at the edge of carbon nitride.
FIG. 3 shows ZnO and g-C in example 1 of the present invention3N4、C3N4Cg/ZnO/CNFe and comparative example C3N4-UV diffuse reflectance spectrum of Cg/ZnO. As shown in the figure, the light absorption edge of the ZnO photocatalyst is around 380nm, i.e. the zinc oxide only responds to ultraviolet light; g-C3N4Has a light absorption edge of 454nm, C3N4The light absorption edge of the-Cg/ZnO photocatalyst is about 458nm, and C3N4The light absorption edge of-Cg/ZnO/CNFe is stronger, and the obvious light absorption extends to the full visible spectrum, which is C3N4The interaction result of-Cg, ZnO and CNFe further proves the successful synthesis of the composite material.
To study the composition and structure of the synthesized sample, the infrared absorption of the sample was analyzed by FTIR, FIG. 4, example 1, in which C is3N4-Cg、CNFe、C3N4Cg/ZnO/CNFe and comparative example C3N4Cg/ZnO Fourier Infrared Spectroscopy. As can be seen from the figure, C3N4Cg and C3N4Cg/ZnO at 810cm-1，1150-1700cm-1，3100-3300cm-1A stronger absorption band appears nearby; CNFe at 1070cm-1，1630cm-1，3280-3680cm-1A weaker absorption peak appears; c3N4The main typical absorption peaks of-Cg/ZnO, CNFe all exist in C3N4Cg/ZnO/CNFe samples, further indicating C3N4Successful synthesis of Cg/ZnO/CNFe composite catalyst.
Photocatalytic degradation experiment:
the photocatalytic oxidation of BPA was carried out in a quartz reactor, a 300W xenon lamp with a filter (400nm) was horizontally placed outside the reactor as a visible light source, and the average light intensity on the surface of the reaction solution in the reaction solution measured by a photon densitometer was 200mW/cm2I.e. 2 standard solar intensities (AM 3G). In order to maintain a constant reaction temperature, a cooling water circulation system was applied around the reactor, and the experiment was performed using magnetic stirring. 100mL of BPA was added to each reactor, the pH was controlled by 0.1M HCl or NaOH, the initial BPA concentration was 10mg/L, the pH was 7, the catalyst dosage was 0.5g/L, and the PMS dosage was 2mM before irradiation, adsorption experiments were performed in the dark for 30 minutes to achieve sufficient contact between BPA and photocatalyst to establish adsorption equilibrium. Finally, BPA concentration changes were monitored and analyzed by high performance liquid chromatography.
FIG. 5 shows pure light, g-C in Experimental example 1 of the present invention3N4、C3N4-Cg、C3N4Cg/ZnO/CNFe and C in comparative example3N4A performance contrast diagram of visible photocatalytic degradation of Cg/ZnO for BPA. As can be seen, the BPA molecules are relatively stable in water and pure light hardly degrades BPA, g-C after 30 minutes of light irradiation3N4The degradation removal efficiency of (1) is 37%, C3N4The degradation removal efficiency of Cg is about 82 percent, C3N4The degradation removal efficiency of-Cg/ZnO is 93 percentLeft and right, however C3N4The degradation removal efficiency of-Cg/ZnO/CNFe is as high as 98.5 percent, and further proves that the degradation removal efficiency is in g-C3N4After the graphene, ZnO and CNFe are introduced, the photocatalytic efficiency is obviously improved.
FIG. 6 shows C prepared in example 1, example 2, example 33N4Cg/ZnO/CNFe and C from comparative example3N4Degradation performance diagram of Cg/ZnO on bisphenol A (BPA). As can be seen from the figure, C is the same as C when CNFe is not added3N4The degradation efficiency of the Cg/ZnO material to BPA in 30 minutes is 93.03%, and when the addition amount of CNFe is 30mg, the degradation efficiency of the nano material to BPA in 30 minutes is 93.5%. When the addition amount of CNFe is 50mg, the degradation efficiency of the nano material to BPA after 30 minutes reaches 94.3%, and when the addition amount of CNFe is 100mg, the degradation efficiency of the nano material to BPA after 30 minutes reaches 98.5%, further explaining that C can be improved by controlling the addition amount of CNFe3N4Catalytic properties of Cg/ZnO/CNFe,
the above results may be caused by that the carbon content affects the photocatalytic performance, and as the addition ratio of CNFe increases, the carbon content gradually increases and the degradation effect gradually increases; on the other hand, the absorbance of the composite material is enhanced, and after too much proportion of CNFe is added, the absorbance is increased, the visible light absorption is enhanced, so that the photocatalysis effect is more obvious, and in addition, when the content of CNFe is gradually increased, more electrons are transferred to a conduction band of ZnO, so that the electron-hole separation efficiency is improved.
Continuous degradation experiments:
after the first degradation reaction is finished, separating the catalyst from the solution with the help of centrifugation, washing the solution with deionized water and ethanol for three times respectively, and storing the solution for later use after drying the solution for about 12 hours in a freeze dryer; carrying out a second degradation reaction by using the materials for standby collection, wherein the reaction conditions except the materials are kept consistent with those of the first degradation reaction; and after the second reaction is finished, repeating the steps and carrying out a third degradation experiment.
FIG. 7 shows a graph C in Experimental example 1 of the present invention3N4Reutilization property of-Cg/ZnO/CNFe visible light catalytic degradation BPAAnd (6) testing. As can be seen from the figure, BPA degradation efficiency was above 95% in three consecutive degradation experiments, which indicates C3N4The photocatalytic activity of the-Cg/ZnO/CNFe photocatalytic nano material still keeps good after three cycles.
The ternary magnetic composite nanomaterial provided by the application and the preparation method and application thereof are introduced in detail, specific examples are applied in the text to explain the principle and the implementation mode of the application, and the description of the examples is only used for helping to understand the method and the core idea of the application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.