CN114146708A - Magnetic TiO2Matrix modified photocatalyst and preparation and application thereof - Google Patents

Magnetic TiO2Matrix modified photocatalyst and preparation and application thereof Download PDF

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CN114146708A
CN114146708A CN202111435974.9A CN202111435974A CN114146708A CN 114146708 A CN114146708 A CN 114146708A CN 202111435974 A CN202111435974 A CN 202111435974A CN 114146708 A CN114146708 A CN 114146708A
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tio
rgo
mixed system
reaction
graphene oxide
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杨磊
姚廷郡
李志洋
李志敏
冷露伟
钟丹
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Shenzhen Graduate School Harbin Institute of Technology
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Shenzhen Graduate School Harbin Institute of Technology
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74—Iron group metals
    • B01J23/745—Iron
    • B01J35/23—
    • B01J35/33—
    • B01J35/39—
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/30—Treatment of water, waste water, or sewage by irradiation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/34—Organic compounds containing oxygen
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/38—Organic compounds containing nitrogen
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2305/00—Use of specific compounds during water treatment
    • C02F2305/08—Nanoparticles or nanotubes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2305/00—Use of specific compounds during water treatment
    • C02F2305/10—Photocatalysts

Abstract

The invention provides a magnetic TiO2A matrix modified photocatalyst and preparation and application thereof. The method comprises the following steps: step 1, preparing TiO2Sol; step 2, dissolving graphene oxide and ferric chloride hexahydrate in organic alcohol to obtain a first mixed system, and dissolving sodium acetate and TiO2Adding the sol and ethylenediamine into the first mixed system in sequence to obtain a second mixed system; step 3, placing the second mixed system in a reaction container for hydrothermal reaction; step 4, carrying out post-treatment on the reaction system after the hydrothermal reaction to obtain TiO2‑x‑rGO/Fe3O4And (3) nano materials. The visible light photocatalyst provided by the invention is stableThe qualitative is good, the degradation rate of the micropollutants is high, and the preparation method is simple; wherein TiO with oxygen holes is attached to the surface of the rGO elementary material2‑xNanoparticles and Fe3O4The nano-particles have the advantages of absorbing visible light of full visible spectrum, being convenient to recycle and reuse and the like, and can be suitable for high-efficiency photocatalytic treatment of neonicotinoid pesticide pollutants.

Description

Magnetic TiO2Matrix modified photocatalyst and preparation and application thereof
Technical Field
The invention relates to the technical field of visible light catalysts, and mainly relates to magnetic TiO2A matrix modified photocatalyst and preparation and application thereof.
Background
The widespread distribution of micropollutants in aquatic environments has become an increasing concern. These contaminants enter the water body primarily through home, hospital, agricultural and industrial activities. The accumulation of neonicotinoid insecticides in the environment can not only affect the survival of pollinating insects, but also cause chronic harm to human health. Studies have shown that prolonged exposure to neonicotinoid insecticides increases the risk of neurodevelopmental dysfunction in children and parkinson's and alzheimer's disease in the elderly.
At present, methods for degrading the pollutants by microorganisms exist, but the traditional technology is complex, low in efficiency and easy to influence by environmental factors. The photocatalysis technology is more and more concerned by people due to the advantages of simple operation, rapid reaction, green and high efficiency and the like. However, due to the physicochemical properties of the semiconductor material, the energy band of the semiconductor material is wide, the semiconductor material can only respond to the ultraviolet interval in sunlight, and the photogenerated electrons and holes are easy to recombine, so that the semiconductor material is not beneficial to degrading pollutants under the condition of visible light.
Therefore, developing a visible light catalytic nano material which has the advantages of simple preparation method, higher visible light utilization rate, higher micro-pollutant degradation rate, better stability and convenient recovery and reuse is a key research target of the technology in the field.
Disclosure of Invention
In order to solve the above problems, the present invention provides a magnetic TiO2The matrix modified photocatalyst and the preparation and application thereof are used for achieving the aims of preparing the visible light catalytic nano material which has higher visible light utilization rate, higher micro-pollutant degradation rate and better stability and is convenient to recycle.
In a first aspect, the present invention provides a magnetic TiO2A base-modified photocatalyst, the magnetic TiO2The matrix modified photocatalyst takes single-layer rGO as a basic material, and TiO is grafted on the basic material2-xNanoparticles and Fe3O4And (3) nanoparticles are obtained.
Preferably, magnetic TiO2The molar ratio of Fe to Ti in the matrix modified photocatalyst is 0.5-2.
In a second aspect, the present invention provides a magnetic TiO2Preparation method of substrate modified photocatalyst for preparing the magnetic TiO described in the first aspect2A substrate-modified photocatalyst, the method comprising:
step 1: preparation of TiO2Sol;
step 2: dissolving graphene oxide and ferric chloride hexahydrate in organic alcohol to obtain a first mixed system, and dissolving sodium acetate and TiO2Adding the sol and ethylenediamine into the first mixed system in sequence to obtain a second mixed system;
and step 3: placing the second mixed system in a reaction container for hydrothermal reaction;
and 4, step 4: post-treating the reaction system after the hydrothermal reaction to obtain TiO2-x-rGO/Fe3O4And (3) nano materials.
Preferably, in the step 1, TiO is prepared2The sol process includes the following steps:
under magnetic stirring, dropwise adding acetic acid and tetrabutyl titanate into anhydrous ethanol at the speed of 4 s/drop and 1 s/drop to obtain a solution A;
adding absolute ethyl alcohol and deionized water into a beaker, and adjusting the pH of the solution to 2 by using dilute nitric acid to prepare a solution B;
slowly adding the solution B into the solution A, and continuously stirring for 30min to obtain TiO2And (3) sol.
Preferably, in the step 2, the dissolving the graphene oxide and the ferric chloride hexahydrate in the organic alcohol includes:
adding the graphene oxide suspension into organic alcohol, and uniformly dispersing by using ultrasonic waves to obtain a graphene oxide mixed system;
and adding an organic alcohol solution of ferric chloride hexahydrate into the graphene oxide mixed system, and uniformly mixing to obtain the first mixed system.
Preferably, in said step 2,
the graphene oxide is high-purity single-layer graphene oxide;
the organic alcohol is ethylene glycol or isopropanol.
Preferably, in the step 3, the reaction time of the hydrothermal reaction is 7-15h, and the reaction temperature is 150-250 ℃.
Preferably, in the step 4, the post-processing includes:
respectively centrifugally washing the reaction system to be neutral by using absolute ethyl alcohol and ultrapure water, wherein the conventional times are 5 times of each absolute ethyl alcohol and ultrapure water, the single centrifugal rotation speed is 8000rpm, and the time is 5 min;
drying the washed product in a freeze dryer for more than or equal to 24 hours to obtain a precursor;
and calcining the precursor in a tubular furnace for 1.5-4.5h at 400-550 ℃ under the protection of nitrogen or vacuum.
In a third aspect, the present invention provides a magnetic TiO2The application of the matrix modified photocatalyst comprises the following components in parts by weight:
mixing the above magnetic TiO2The matrix modified photocatalyst is used for high-efficiency photocatalytic treatment of neonicotinoid pesticide pollutants.
The invention attaches TiO with oxygen cavity on the surface of rGO elementary material2-xNanoparticles and Fe3O4Preparation of TiO from nanoparticles2-x-rGO/Fe3O4And (3) nano materials. Wherein, TiO2The photocatalyst is the most widely applied photocatalyst in semiconductors, has the attractive characteristics of no toxicity, low cost, excellent chemical stability, corrosion resistance, excellent photocatalytic performance and the like, and is a preferred material for preparing the photocatalyst. First of all, TiO is prepared2Sols, usually pure anatase TiO2The light absorption boundary is about 390nm, and TiO is obtained by doping to a certain degree2-rGO/Fe3O4The light absorption boundary of the composite material may be red-shifted. Finally by calcining TiO in the absence of oxygen2-rGO/Fe3O4Preparation of TiO2-x-rGO/Fe3O4Composite material, TiO2-x-rGO/Fe3O4The light absorption range of the composite material can be widened to the full visible spectrum, and the light capture efficiency of the composite material is obviously improved. And Fe3O4As a typical magnetic material, its addition can effectively solve TiO2-xThe separation problem and the secondary pollution problem of the rGO photocatalyst and the photocatalytic performance of the catalyst are effectively improved. In general, the magnetic TiO2The matrix modified photocatalyst is simple to prepare, has higher visible light utilization rate, higher micro-pollutant degradation rate and better stability, and is convenient to recycle.
The method of the invention can achieve the following advantages: (1) the raw materials used in the invention, such as rGO, tetrabutyl titanate, anhydrous ethylenediamine, ferric chloride hexahydrate and the like, are low-toxicity or even non-toxic, have wide sources and low cost, and the prepared TiO is2The composite material obtained by subsequent hydrothermal reaction and high-temperature calcination has excellent photocatalytic performance, greatly improves the utilization rate of sunlight, and has a remarkable effect on the degradation of micro-pollutants. (2) As a typical magnetic material, Fe3O4Can effectively solve the problem of TiO2-xSeparation problems and secondary pollution problems of rGO photocatalysts, therefore the present invention is conveniently recyclable and recyclable. (3) The preparation method is simple, the cost is low, and the reaction is carried outThe conditions are relatively mild, which is beneficial to high-quality TiO2-x/rGO-Fe3O4And (4) producing the nano material.
In summary, the magnetic TiO of the invention2The preparation method of the matrix modified photocatalyst comprises the steps of firstly preparing TiO2Dissolving graphene oxide and ferric chloride hexahydrate in organic alcohol to obtain a first mixed system, and dissolving the prepared TiO2Sequentially adding the sol, sodium acetate and ethylenediamine into the first mixed system to obtain a second mixed system, carrying out hydrothermal reaction, and carrying out post-treatment to obtain TiO2-x/rGO-Fe3O4And (3) nano materials. The method has mild reaction conditions in each step, is simple to operate and low in cost, and greatly improves the preparation efficiency.
Drawings
FIG. 1 shows TiO in an example of the invention2-x-rGO/Fe3O4A flow diagram of a method of preparing a material;
FIG. 2 shows TiO prepared in example 1 of the present invention2-x-rGO/Fe3O4SEM images of nanoparticles;
FIG. 3 shows TiO in example 1 of the present invention2、TiO2-rGO、TiO2-x-rGO and TiO2-x-rGO/Fe3O4Ultraviolet diffuse reflection spectrogram;
FIG. 4 shows TiO in example 1 of the present invention2、TiO2-rGO、TiO2-x-rGO and TiO2-x-rGO/Fe3O4A Fourier infrared spectrum;
FIG. 5 shows TiO in Experimental example 1 of the present invention2、TiO2-rGO、TiO2-x-rGO and TiO2-x-rGO/Fe3O4A performance contrast chart of visible light catalytic degradation imidacloprid;
FIG. 6 shows TiO prepared in example 1 of the present invention2-x-rGO/Fe3O4A performance contrast diagram of the material for degrading imidacloprid under visible light catalysis under different environmental conditions of pure illumination, PS and PMS;
FIG. 7 shows TiO in example 1 of the present invention2-x-rGO and TiO2-x-rGO/Fe3O4Nitrogen adsorption-desorption isotherm diagram of material
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, embodiments of the present invention provide a magnetic TiO2A base-modified photocatalyst, the magnetic TiO2The matrix modified photocatalyst takes single-layer rGO as a basic material, and TiO is grafted on the basic material2-xNanoparticles and Fe3O4Obtained from nanoparticles of said magnetic TiO2The molar ratio of Fe to Ti in the matrix modified photocatalyst is 0.5-2.
Wherein titanium dioxide (TiO)2) The photocatalyst is the most widely applied photocatalyst in other semiconductors, and has the attractive characteristics of no toxicity, low cost, excellent chemical stability, corrosion resistance, excellent photocatalytic performance and the like. However, TiO2The particles are easily aggregated, difficult to recover, easily cause secondary pollution, and the photo-generated electron-hole pairs have a high recombination rate, which limits their applications.
Based on the method, the embodiment of the invention provides the method for doping rGO to generate TiO2-xrGO composites, and TiO2-x-rGO composite material having excellent electron mobility (200000 cm)2·V-1·s-1) And large specific surface area, and has the advantages of large capacity, large effective catalytic surface area of reaction, high mass transfer rate of liquid to photocatalyst, and the like.
Further, Fe3O4As a typical magnetic material, its addition can effectively solve TiO2-xSeparation of rGO photocatalystProblems and secondary pollution problems. Further, according to the energy level theory, Fe3O4Not only can maintain unique superparamagnetism, but also can accelerate photoinduced electrons to be in two oxidation states (Fe) of iron3+，Fe2+) Thereby improving TiO content2Photocatalytic activity of (1).
In a second aspect, embodiments of the present invention provide a magnetic TiO2Preparation method of substrate modified photocatalyst for preparing the magnetic TiO described in the first aspect2A substrate-modified photocatalyst, the method comprising:
step 1: preparation of TiO2Sol;
step 2: dissolving graphene oxide and ferric chloride hexahydrate in organic alcohol to obtain a first mixed system, and dissolving sodium acetate and TiO2Adding the sol and ethylenediamine into the first mixed system in sequence to obtain a second mixed system;
in the embodiment of the invention, the addition of the ethylenediamine can not only prepare Fe with the first mixed system3O4And the particle size of the composite material can be effectively improved, and a nano material with smaller particle size can be formed.
And step 3: placing the second mixed system in a reaction container for hydrothermal reaction;
and 4, step 4: post-treating the reaction system after the hydrothermal reaction to obtain TiO2-x-rGO/Fe3O4And (3) nano materials.
Preferably, in the step 1, TiO is prepared2The sol process includes the following steps:
under magnetic stirring, dropwise adding acetic acid and tetrabutyl titanate into anhydrous ethanol at the speed of 4 s/drop and 1 s/drop to obtain a solution A;
adding absolute ethyl alcohol and deionized water into a beaker, and adjusting the pH of the solution to 2 by using dilute nitric acid to prepare a solution B;
slowly adding the solution B into the solution A, and continuously stirring for 30min to obtain TiO2And (3) sol.
In the examples of the present invention, when tetrabutyl titanate is added dropwise to anhydrous ethanol, hydrolysis reaction also occurs, namelyThe generation of hydrolysis reaction is inhibited, acetic acid is additionally dripped into the absolute ethyl alcohol, and the dripping speeds of the acetic acid and the tetrabutyl titanate are respectively 4 s/drop and 1 s/drop, and the dripping is carried out at the speed, so that the hydrolysis reaction speed can be effectively reduced; furthermore, by using TiO2Sol form to facilitate TiO in subsequent synthesis steps2Natural crystallization of nanoparticles to the surface of the support (rGO) resulting in the formation of TiO2The particle size is small, the purity is high, the dispersibility is good, and the TiO can be effectively improved2Agglomeration of particles on the surface of the support (rGO).
Preferably, in the step 2, the dissolving the graphene oxide and the ferric chloride hexahydrate in the organic alcohol includes:
adding the graphene oxide suspension into organic alcohol, and uniformly dispersing by using ultrasonic waves to obtain a graphene oxide mixed system;
and adding an organic alcohol solution of ferric chloride hexahydrate into the graphene oxide mixed system, and uniformly mixing to obtain the first mixed system.
Preferably, in said step 2,
the graphene oxide is high-purity single-layer graphene oxide;
the organic alcohol is ethylene glycol or isopropanol.
Preferably, in the step 3, the reaction time of the hydrothermal reaction is 7-15h, and the reaction temperature is 150-250 ℃.
In comparison with a gas phase method, the embodiment of the invention prepares TiO by hydrothermal reaction2The reaction condition is mild, the operation is simple and the cost is low; in addition, under the hydrothermal reaction conditions, the range of the hydrothermal reaction time and the hydrothermal reaction temperature is more favorable for TiO2Formation of TiO in anatase form2Relatively ordinary TiO2Anatase form of TiO2Is stronger in light absorption capacity.
Preferably, in the step 4, the post-processing includes:
respectively centrifugally washing the reaction system to be neutral by using absolute ethyl alcohol and ultrapure water, wherein the conventional times are 5 times of each absolute ethyl alcohol and ultrapure water, the single centrifugal rotation speed is 8000rpm, and the time is 5 min;
drying the washed product in a freeze dryer for more than or equal to 24 hours to obtain a precursor;
and calcining the precursor in a tubular furnace for 1.5-4.5h at 400-550 ℃ under the protection of nitrogen.
Since the organic solvent is introduced in the synthesis process of the embodiment of the present invention, in the step 4, if only washing with ultrapure water is performed, the organic solvent is easily remained, and the organic solvent can be effectively removed by using respective centrifugal washing with anhydrous ethanol and ultrapure water. In addition, certain volatilization can be generated in the composite material calcining process, and the smoothness of a gas passage can be ensured by calcining under the protection of argon, so that the influence of volatile matters on the composite material is effectively reduced.
The above-described preferred conditions may be combined with each other to obtain a specific embodiment, in accordance with common knowledge in the art.
In a third aspect, embodiments of the present invention provide the magnetic TiO of the first aspect2Application of a matrix modified photocatalyst.
Mixing the above magnetic TiO2The matrix modified photocatalyst is used for high-efficiency photocatalytic treatment of neonicotinoid pesticide pollutants.
Magnetic TiO2After the substrate modified photocatalyst is irradiated by light, excited free electrons are formed by TiO2The valence band of (a) is transited to the conduction band and is associated with H in the water body2The reaction of O produces hydroxyl radicals, which react with dissolved oxygen in water to produce superoxide radicals. Because the catalyst has a large number of cavities and the combined action of the active oxidation substances (hydroxyl free radicals and superoxide free radicals), the neonicotinoid pesticide can be oxidized into small molecular substances or mineralized into CO2、H2O, and the like.
In order that those skilled in the art will better understand the present invention, the following description will illustrate the magnetic TiO provided by the present invention by means of several specific examples2A preparation method of a matrix modified photocatalyst.
Example 1
Step 1:20mL of absolute ethanol was placed in a beaker, and 1.5mL of acetic acid and 5mL of tetrabutyl titanate were added dropwise at a rate of 4 s/drop and 1 s/drop under magnetic stirring. The resulting mixed liquid was labeled as solution a. 17ml of absolute ethyl alcohol and 3ml of deionized water were added to a beaker, and the pH of the solution was adjusted to 2 with dilute nitric acid to obtain a solution B. Slowly adding the solution B into the solution A, and continuously stirring for 30min to obtain TiO2And (3) sol.
Step 2: 20g of the graphene oxide suspension was added to 150mL of ethylene glycol, and dispersed into the homogeneous mixed solution with ultrasonic waves. Meanwhile, 1g of ferric chloride hexahydrate is dissolved in 10mL of ethylene glycol, the mixture is added into a dispersed graphene oxide mixed system after complete dissolution, the first mixed system is obtained by stirring at a constant speed, then 3g of sodium acetate, 2mL of titanium dioxide sol and 10mL of ethylenediamine are sequentially added into the first mixed system, and the second mixed system is obtained by continuously stirring for 30 minutes.
And step 3: transferring the second mixed system into a Teflon stainless steel reaction vessel, heating at 150-250 ℃ for 7-15h, and naturally cooling to room temperature.
And 4, step 4: respectively centrifugally washing a reaction system after the hydrothermal reaction to be neutral by using absolute ethyl alcohol and ultrapure water, wherein the conventional times are 5 times of each absolute ethyl alcohol and ultrapure water, the single centrifugal rotation speed is 8000rpm, the time is 5min, and drying for at least 24h in a freeze dryer to obtain a precursor; calcining the prepared precursor in a tubular furnace at 400-550 ℃ under the protection of argon for 1.5-4.5h to obtain TiO2-x-rGO/Fe3O4A composite material. Repeating the above operations to obtain the nano composite material with the molar ratio of Fe to Ti of 0.5:1 respectively, which is marked as TiO2-x-rGO/Fe3O4-1。
Example 2
Step 1: 20mL of absolute ethanol was placed in a beaker, and 1.5mL of acetic acid and 5mL of tetrabutyl titanate were added dropwise at a rate of 4 s/drop and 1 s/drop under magnetic stirring. The resulting mixed liquid was labeled as solution a. 17ml of absolute ethyl alcohol and 3ml of deionized water were added to a beaker, and the pH of the solution was adjusted to 2 with dilute nitric acid to obtain a solution B. Slowly adding the solution B into the solution A, and continuously stirring for 30min to obtainTiO2And (3) sol.
Step 2: 20g of the graphene oxide suspension was added to 150mL of ethylene glycol, and dispersed into the homogeneous mixed solution with ultrasonic waves. Meanwhile, 1g of ferric chloride hexahydrate is dissolved in 10mL of ethylene glycol, the mixture is added into a dispersed graphene oxide mixed system after complete dissolution, the first mixed system is obtained by stirring at a constant speed, then 3g of sodium acetate, 2mL of titanium dioxide sol and 10mL of ethylenediamine are sequentially added into the first mixed system, and the second mixed system is obtained by continuously stirring for 30 minutes.
And step 3: transferring the second mixed system into a Teflon stainless steel reaction vessel, heating at 150-250 ℃ for 7-15h, and naturally cooling to room temperature.
And 4, step 4: respectively centrifugally washing a reaction system after the hydrothermal reaction to be neutral by using absolute ethyl alcohol and ultrapure water, wherein the conventional times are 5 times of each absolute ethyl alcohol and ultrapure water, the single centrifugal rotation speed is 8000rpm, the time is 5min, and drying for at least 24h in a freeze dryer to obtain a precursor; calcining the prepared precursor in a tubular furnace at 400-550 ℃ under the protection of argon for 1.5-4.5h to obtain TiO2-x-rGO/Fe3O4A composite material. Repeating the above operations to obtain the nano composite material with the molar ratio of Fe to Ti being 1:1 respectively, and marking as TiO2-x-rGO/Fe3O4-2。
Example 3
Step 1: 20mL of absolute ethanol was placed in a beaker, and 1.5mL of acetic acid and 5mL of tetrabutyl titanate were added dropwise at a rate of 4 s/drop and 1 s/drop under magnetic stirring. The resulting mixed liquid was labeled as solution a. 17ml of absolute ethyl alcohol and 3ml of deionized water were added to a beaker, and the pH of the solution was adjusted to 2 with dilute nitric acid to obtain a solution B. Slowly adding the solution B into the solution A, and continuously stirring for 30min to obtain TiO2And (3) sol.
Step 2: 20g of the graphene oxide suspension was added to 150mL of ethylene glycol, and dispersed into the homogeneous mixed solution with ultrasonic waves. Meanwhile, 1g of ferric chloride hexahydrate is dissolved in 10mL of ethylene glycol, the mixture is added into a dispersed graphene oxide mixed system after complete dissolution, the first mixed system is obtained by stirring at a constant speed, then 3g of sodium acetate, 2mL of titanium dioxide sol and 10mL of ethylenediamine are sequentially added into the first mixed system, and the second mixed system is obtained by continuously stirring for 30 minutes.
And step 3: transferring the second mixed system into a Teflon stainless steel reaction vessel, heating at 150-250 ℃ for 7-15h, and naturally cooling to room temperature.
And 4, step 4: respectively centrifugally washing a reaction system after the hydrothermal reaction to be neutral by using absolute ethyl alcohol and ultrapure water, wherein the conventional times are 5 times of each absolute ethyl alcohol and ultrapure water, the single centrifugal rotation speed is 8000rpm, the time is 5min, and drying for at least 24h in a freeze dryer to obtain a precursor; calcining the prepared precursor in a tubular furnace at 400-550 ℃ under the protection of argon for 1.5-4.5h to obtain TiO2-x-rGO/Fe3O4A composite material. Repeating the above operations to obtain the nano composite material with the molar ratio of Fe to Ti of 1.5:1 respectively, which is marked as TiO2-x-rGO/Fe3O4-3。
To further illustrate the magnetic TiO prepared by the present invention2The matrix modified photocatalyst has the advantages of high utilization rate of visible light and high degradation rate of micro pollutants, and is analyzed by combining a specific figure.
FIG. 1 shows a magnetic TiO compound in an embodiment of the invention2A flow chart of a method for preparing a substrate-modified photocatalyst. As can be seen from the figure, TiO is first prepared in the present invention2Dissolving graphene oxide and ferric chloride hexahydrate in organic alcohol to obtain a first mixed system, and dissolving the prepared TiO2Sequentially adding the sol, sodium acetate and ethylenediamine into the first mixed system to obtain a second mixed system, carrying out hydrothermal reaction, and carrying out post-treatment to obtain TiO2-x/rGO-Fe3O4And (3) nano materials.
FIG. 2 shows TiO prepared in example 1 of the present invention2-x-rGO/Fe3O4SEM image of nanoparticles. As can be seen from the figure, the sheet structure of the middle part is rGO, and TiO is grafted on the rGO2Particles and Fe3O4And (3) granules.
FIG. 3 is a diagram of the UV absorption spectra of catalysts with different ratios, and the absorption spectra of the catalysts are analyzed by UV diffuse reflectance spectroscopy. Pure anatase type TiO2、TiO2/rGO、TiO2-x-rGO and TiO2-x-rGO/Fe3O4The light absorption boundary of (2) is about 390 nm. With pure anatase type TiO2In contrast, the light absorption boundaries of the composite materials with different doping ratios are all significantly red-shifted. To in TiO2The visible light absorption range of the composite material is further increased on the basis of rGO, and TiO is prepared by calcining under the argon condition2-xrGO composite, with a visible light absorption boundary of the composite clearly red-shifted before and after calcination. Further, by introducing Fe3O4To obtain TiO2-x-rGO/Fe3O4A composite material. In TiO2-xBased on-rGO, TiO2-x-rGO/Fe3O4The visible light absorption boundary is further red-shifted, the light absorption range is obviously widened to the full visible spectrum, and the light capture efficiency is greatly improved.
FIG. 4 shows TiO in example 1 of the present invention2、TiO2-rGO、TiO2-x-rGO and TiO2-x-rGO/Fe3O4Fourier infrared spectrum, mainly using Fourier transform infrared spectrum (FT-IR) to research the structural functional group of the composite nanometer material. The sample is 1633cm-1And 3423cm-1The nearby absorption peak corresponds to the stretching vibration of the O-H bond on the surface of the material and is 590cm-1The absorption peak is caused by the stretching vibration of the Fe-O bond. In the spectrum of pure TiO2, below 800cm-1The absorption peaks at 3415cm-1 and 1633cm-1 are probably caused by bending and stretching vibration of H2O or-OH O-H bonds adsorbed on the surface of TiO 2. In addition, for Fe3O4590cm of Fe-O band vibration-1The bands on the left and right generally correspond to iron cations at tetrahedral sites, while another strong peak appears below 800cm-1 due to the Ti-O-Ti group, confirming Fe3O4And TiO2The nano particles are formed in the hydrothermal processGrafting onto rGO sheet. In addition, in TiO2-x/rGO-Fe3O4In the composite catalyst, the characteristic peaks of TiO2 and rGO are clearly visible, while Fe3O4Is mainly due to Fe3O4Too low doping content.
Organic matter degradation experiments are carried out on the materials prepared by the specific examples, and the experimental environment is under a PMS system. FIG. 5 shows TiO prepared in example 12-x-rGO/Fe3O4Photocatalytic nano material and common TiO2Nanoparticles, TiO2rGO and TiO2-xa/rGO performance contrast diagram of visible light catalytic degradation of imidacloprid. Ordinary TiO2Nanoparticles and TiO2rGO can only remove 20% or so of TiO in 30 minutes2-xThe removal rate of the-rGO photocatalytic nano material to imidacloprid can only reach about 80 percent within 30 minutes, while TiO2-x-rGO/Fe3O4The degradation efficiency of the photocatalytic nano material to imidacloprid within 30 minutes is as high as 99%.
FIG. 6 shows TiO prepared in example 1 of the present invention2-x-rGO/Fe3O4A performance contrast chart of the material for visible light catalytic degradation of imidacloprid under different environmental conditions of pure illumination, PS and PMS reflects the degradation capability of the photocatalytic nano degradation material on imidacloprid organic pollutants under different environmental conditions. It can be seen from the figure that the imidacloprid molecule is relatively stable in water, the concentration of the imidacloprid does not change greatly after being illuminated by pure light, the imidacloprid is reduced by about 40 percent after PS is added, and the residual content of the imidacloprid is almost 0 in a PMS environment.
FIG. 7 shows TiO in example 1 of the present invention2-x-rGO and TiO2-x-rGO/Fe3O4The nitrogen adsorption-desorption isotherm diagram of the material reflects the nitrogen adsorption and desorption capacities of the two materials, and then the specific surface areas of the two materials are compared. As can be seen from the figure, TiO2-x-rGO/Fe3O4The nitrogen adsorption and desorption capacity of the catalyst is stronger than that of TiO2-xrGO, i.e. in TiO2-x-introduction of Fe on the basis of rGO3O4The specific surface area of the material is increased.
The magnetic TiO provided by the invention2The matrix modified photocatalyst, the preparation and the application thereof are introduced in detail, the principle and the implementation mode of the application are explained by applying specific examples, 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.

Claims (10)

1. Magnetic TiO2The base body modified photocatalyst is characterized in that the catalyst takes single layer rGO as a basic material, and TiO is grafted on the basic material2-xNanoparticles and Fe3O4Nanoparticle derived TiO2-x-rGO/Fe3O4And (3) nano materials.
2. The catalyst of claim 1, wherein the TiO is selected from the group consisting of2-xWherein x is 0.05 to 0.45.
3. The catalyst of claim 1, wherein the TiO is selected from the group consisting of2-x-rGO/Fe3O4The molar ratio of Fe to Ti in the nano material is 0.5-2.
4. A method for preparing the catalyst of any one of claims 1 to 3, wherein the method comprises:
step 1, preparing TiO2Sol;
step 2, dissolving graphene oxide and ferric chloride hexahydrate in organic alcohol to obtain a first mixed system, and dissolving sodium acetate and TiO2Adding the sol and ethylenediamine into the first mixed system in sequence to obtain a second mixed system;
step 3, placing the second mixed system in a reaction container for hydrothermal reaction;
step 4, carrying out post-treatment on the reaction system after the hydrothermal reaction to obtain TiO2-x-rGO/Fe3O4And (3) nano materials.
5. The production method according to claim 4, wherein in the step 1, TiO is produced2The sol process includes the following steps:
under magnetic stirring, dropwise adding acetic acid and tetrabutyl titanate into anhydrous ethanol at the speed of 4 s/drop and 1 s/drop to obtain a solution A;
adding absolute ethyl alcohol and deionized water into a beaker, and adjusting the pH of the solution to 2 by using dilute nitric acid to prepare a solution B;
slowly adding the solution B into the solution A, and continuously stirring for 30min to obtain TiO2And (3) sol.
6. The preparation method according to claim 4, wherein in the step 2, the dissolving of the graphene oxide and the ferric chloride hexahydrate in the organic alcohol comprises:
adding the graphene oxide suspension into organic alcohol, and uniformly dispersing by using ultrasonic waves to obtain a graphene oxide mixed system;
and adding an organic alcohol solution of ferric chloride hexahydrate into the graphene oxide mixed system, and uniformly mixing to obtain the first mixed system.
7. The production method according to claim 4, wherein, in the step 2,
the graphene oxide is high-purity single-layer graphene oxide;
the organic alcohol is ethylene glycol or isopropanol.
8. The preparation method as claimed in claim 4, wherein in the step 3, the reaction time of the hydrothermal reaction is 7-15h, and the reaction temperature is 150-250 ℃.
9. The production method according to claim 4, wherein in the step 4, the post-treatment includes:
respectively centrifugally washing the reaction system to be neutral by using absolute ethyl alcohol and ultrapure water, wherein the conventional times are 5 times of each absolute ethyl alcohol and ultrapure water, the single centrifugal rotation speed is 8000rpm, and the time is 5 min;
drying the washed product in a freeze dryer for more than or equal to 24 hours to obtain a precursor;
and calcining the precursor in a tubular furnace for 1.5-4.5h under the protection of argon at 400-550 ℃.
10. Magnetic TiO2The application of the matrix modified photocatalyst is characterized in that the application is as follows:
the catalyst of any one of claims 1 to 3 is used for high-efficiency photocatalytic treatment of neonicotinoid pesticide pollutants.
CN202111435974.9A 2021-11-26 2021-11-26 Magnetic TiO2Matrix modified photocatalyst and preparation and application thereof Pending CN114146708A (en)

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