CN107175112B - A kind of micromotor photocatalyst and its preparation method and application - Google Patents

Abstract

the invention discloses a micro-motor photocatalyst, which is used for synthesizing α -Fe by a solvothermal method ₂O₃‑ZnFe₂O₄Micromotor photocatalyst microspheres of ZnFe ₂O₄the diameter of the hollow microsphere is 0.4-0.8 μm, and the flake alpha-Fe ₂O₃And Mn ₂O₃Nanoparticles grown on ZnFe ₂O₄On the microspheres. The invention also discloses a preparation method and application thereof. The micromotor photocatalyst has a magnetic microsphere structure, is beneficial to recovery and magnetic control, and can catalyze H ₂O₂Generating bubbles to perform autonomous movement at H ₂O₂Has better degradation efficiency on organic pollutants in the dye wastewater under the participated UV-Fenton reaction, and can be used for the efficient treatment of the dye wastewater And (6) processing. In the reaction system H ₂O₂not only used as a reagent for UV-Fenton reaction, but also used for promoting alpha-Fe ₂O₃‑ZnFe₂O₄Fuel for the micro-motor.

Description

A kind of micromotor photocatalyst and its preparation method and application

technical field

The invention relates to a self-driven motor photocatalyst in the aspect of sewage treatment, in particular to a micromotor photocatalyst and a preparation method and application thereof.

Background technique

Water pollution in today's society is becoming more and more serious, and dye wastewater is one of the most serious pollution in water pollution. The treatment of dye wastewater generally includes adsorption, catalysis, chemical, biological and other methods. Among them, the catalytic method can realize the deep oxidation of refractory substances to obtain harmless inorganic substances and is widely used, and the photocatalytic technology has no secondary pollution.

Fenton and its related reactions are reactions of oxides (usually H ₂ O ₂ ) with iron ions to form reactive oxygen species ( OH) that oxidize organic or inorganic compounds. The Fenton method is simple to operate, green and non-toxic, and its superior oxidation performance can achieve deep oxidation of refractory substances. However, it can effectively play its catalytic role in strong acid, and it produces secondary pollution caused by iron sludge and high treatment costs. UV-Fenton, which combines Fenton method and light technology, can solve such problems. , and improve the utilization rate of H ₂ O ₂ .

ZnFe ₂ O ₄ has a narrow band gap, can be used as a catalyst and catalyst carrier, and has magnetic properties, which is conducive to recycling, but its photocatalytic degradation of organic pollutants is poor. ZnFe ₂ O ₄ can be combined with α-Fe ₂ O ₃ and H _2O2 undergoes UV _- Fenton reaction to generate hydroxyl radicals to degrade organic pollutants. Micromotors are artificial devices that convert chemical or other forms of energy into mechanical energy on the micrometer scale. The driving methods include chemical, magnetic, light, ultrasonic, etc. The commonly used catalyst is reacting with hydrogen peroxide to generate bubbles as the driving force. In the present invention, ZnFe ₂ O ₄ is compounded with α-Fe ₂ O ₃ and Mn ₂ O ₃ , Mn ₂ O ₃ reacts with H ₂ O ₂ to generate oxygen to drive motor movement, ZnFe ₂ O ₄ and α-Fe ₂ O ₃ and H ₂ O ₂ reacts to generate hydroxyl radicals to degrade organic pollutants, and the photo-Fenton technology is combined with a motor to degrade organic pollutants. H ₂ O ₂ serves as the reagent for the Fenton reaction and as the fuel to propel the micromotor. The importance of the motor of the present invention is that it opens up a way of making autonomous microscopic cleaning systems that can operate without external energy input and in a much faster manner than their static counterparts.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a micromotor photocatalyst.

The invention also provides a preparation method and application of the micromotor photocatalyst.

The present invention is achieved through the following technical solutions:

_A micromotor photocatalyst, α _{- Fe2O3 -} ZnFe2O4 micromotor photocatalyst microspheres are synthesized by a solvothermal method, wherein the diameter of the _ZnFe2O4 hollow microspheres is 0.4-0.8 μm, and the sheet _- like α- _Fe2O3 and _Mn2O3 nanoparticles _were grown _{on ZnFe2O4} microspheres _.

Said, the particle size of the α-Fe ₂ O ₃ -ZnFe ₂ O ₄ micromotor photocatalyst microspheres is 0.5-1 μm.

A preparation method of a micromotor photocatalyst is prepared by the following steps:

1) Add Zn(CH ₃ COO) ₂ · 2H ₂ O and Fe(NO ₃ ) ₃ · 9H ₂ O to the mixed solution, stir magnetically for 10 minutes, then add to the reaction kettle for reaction, cool down to room temperature after completion, and wash with distilled water for 3 second, drying to obtain the precursor of ZnFe ₂ O ₄ hollow microspheres;

2) Take 3-5mL of 50% manganese nitrate solution and dilute it to 15mL with distilled water to obtain a manganese nitrate dilute solution; add Fe(NO ₃ ) ₃ 9H ₂ O to the manganese nitrate dilute solution and mix well, then add 0.5g of ZnFe The precursor of ₂ O ₄ hollow microspheres is impregnated, filtered, dried, calcined, and cooled to room temperature to obtain a micromotor photocatalyst.

In the step 1), the mixed solution was prepared from 18 mL of glycerol and 60 mL of isopropanol; the addition amount of Zn(CH ₃ COO) ₂ ·2H ₂ O was 1 mmol; Fe(NO ₃ ) ₃ ·9H The amount of ₂ O added was 2 mmol; the reaction temperature was 180 °C, the reaction time was 12 h, and the drying temperature was 80 °C.

In the step 2), the dosage of Fe(NO ₃ ) ₃ ·9H ₂ O is 200 mg; the impregnation time is 2 h; the drying temperature is 80° C.; the calcination temperature is 500° C., and the calcination time is 1 h.

The micromotor photocatalyst is used for catalyzing degradation of dye wastewater; under the participation of H ₂ O ₂ , simulating ultraviolet light irradiation conditions catalyzes degradation of dye wastewater.

Said, the organic matter concentration in the dye wastewater is 5mg/L, the dosage of the micromotor photocatalyst is 1g/L, the volume ratio of H ₂ O ₂ to the dye solution is 1:50, and the simulated ultraviolet light irradiation time is 1-45min.

Said, the concentration of H ₂ O ₂ is 30%.

Beneficial effects of the present invention:

_{The micromotor} photocatalyst of the invention has a magnetic microsphere structure, which is beneficial to recovery and magnetic control, and can catalyze H ₂ O ₂ to generate bubbles to move autonomously. The pollutants have good degradation efficiency and can be used for efficient treatment of dye wastewater. In this reaction system, H ₂ O ₂ acts as both the reagent for UV-Fenton reaction and the fuel for propelling the α-Fe ₂ O ₃ -ZnFe ₂ O ₄ micromotor. The preparation method of the invention has mild conditions, low energy consumption and easy operation in the preparation process.

Description of drawings

Figure 1 is a graph showing the degradation of methylene blue by the micromotor photocatalyst prepared in Examples 1-3 under simulated ultraviolet light.

FIG. 2 is the SEM image, EDS spectrum, TEM, HRTEM and mapping photos of the micromotor photocatalyst prepared in Example 3. FIG.

In the figure, (a), (b) and (c) are the SEM images of the micromotor photocatalyst; (d) is the EDS spectrum of the micromotor photocatalyst; (e) is the TEM image of the micromotor photocatalyst; (f) ) are the HRTEM images of the micromotor photocatalyst, and (g), (h), (i) and (j) are the corresponding mapping images of the micromotor photocatalyst.

FIG. 3 is the XRD curve of the micromotor photocatalyst prepared in Example 3. FIG.

FIG. 4 is a SEM image of the ZnFe ₂ O ₄ hollow microspheres prepared in Example 3. FIG.

FIG. 5 is the hysteresis loop of the micromotor photocatalyst prepared in Example 3 at room temperature.

FIG. 6 is the UV-Vis spectra of the micromotor photocatalyst prepared in Example 3 for methylene blue after different catalysis times.

Detailed ways

The present invention will be further described below in conjunction with the embodiments.

Example 1

_A micromotor photocatalyst, α _{- Fe2O3 -} ZnFe2O4 micromotor photocatalyst microspheres are synthesized by a solvothermal method, wherein the diameter of the _ZnFe2O4 hollow microspheres is 0.4-0.8 μm, and the sheet _- like α- _Fe2O3 and _Mn2O3 nanoparticles _were grown _{on ZnFe2O4} microspheres _.

Said, the particle size of the α-Fe ₂ O ₃ -ZnFe ₂ O ₄ micromotor photocatalyst microspheres is 0.5-1 μm.

A preparation method of a micromotor photocatalyst is prepared by the following steps:

1) Add Zn(CH ₃ COO) ₂ · 2H ₂ O and Fe(NO ₃ ) ₃ · 9H ₂ O to the mixed solution, stir magnetically for 10 minutes, then add to the reaction kettle for reaction, cool down to room temperature after completion, and wash with distilled water for 3 second, drying to obtain the precursor of ZnFe ₂ O ₄ hollow microspheres;

In the step 1), the mixed solution was prepared from 18 mL of glycerol and 60 mL of isopropanol; the addition amount of Zn(CH ₃ COO) ₂ ·2H ₂ O was 1 mmol; Fe(NO ₃ ) ₃ ·9H The amount of ₂ O added was 2 mmol; the reaction temperature was 180 °C, the reaction time was 12 h, and the drying temperature was 80 °C.

2) Take 3 mL of 50% manganese nitrate solution and dilute it to 15 mL with distilled water to obtain a dilute solution of manganese nitrate; add Fe(NO ₃ ) ₃ 9H ₂ O to the dilute manganese nitrate solution and mix well, then add 0.5 g of ZnFe ₂ O _4. The precursor of the hollow microspheres is impregnated, filtered, dried, calcined, and cooled to room temperature to obtain a micromotor photocatalyst.

In the step 2), the dosage of Fe(NO ₃ ) ₃ ·9H ₂ O is 200 mg; the impregnation time is 2 h; the drying temperature is 80° C.; the calcination temperature is 500° C., and the calcination time is 1 h.

The micromotor photocatalyst is used for catalyzing degradation of dye wastewater; under the participation of H ₂ O ₂ , simulating ultraviolet light irradiation conditions catalyzes degradation of dye wastewater.

Said, the organic matter concentration in the dye wastewater is 5mg/L, the dosage of the micromotor photocatalyst is 1g/L, the volume ratio of H ₂ O ₂ to the dye solution is 1:50, and the simulated ultraviolet light irradiation time is 1-45min.

Said, the concentration of H ₂ O ₂ is 30%.

Example 2

_A micromotor photocatalyst, α _{- Fe2O3 -} ZnFe2O4 micromotor photocatalyst microspheres are synthesized by a solvothermal method, wherein the diameter of the _ZnFe2O4 hollow microspheres is 0.4-0.8 μm, and the sheet _- like α- _Fe2O3 and _Mn2O3 nanoparticles _were grown _{on ZnFe2O4} microspheres _.

Said, the particle size of the α-Fe ₂ O ₃ -ZnFe ₂ O ₄ micromotor photocatalyst microspheres is 0.5-1 μm.

A preparation method of a micromotor photocatalyst is prepared by the following steps:

1) Add Zn(CH ₃ COO) ₂ · 2H ₂ O and Fe(NO ₃ ) ₃ · 9H ₂ O to the mixed solution, stir magnetically for 10 minutes, then add to the reaction kettle for reaction, cool down to room temperature after completion, and wash with distilled water for 3 second, drying to obtain the precursor of ZnFe ₂ O ₄ hollow microspheres;

2) Take 4 mL of 50% manganese nitrate solution and dilute it to 15 mL with distilled water to obtain a dilute solution of manganese nitrate; add Fe(NO ₃ ) ₃ 9H ₂ O to the dilute manganese nitrate solution and mix well, then add 0.5 g of ZnFe ₂ O _4. The precursor of the hollow microspheres is impregnated, filtered, dried, calcined, and cooled to room temperature to obtain a micromotor photocatalyst.

In the step 1), the mixed solution was prepared from 18 mL of glycerol and 60 mL of isopropanol; the addition amount of Zn(CH ₃ COO) ₂ ·2H ₂ O was 1 mmol; Fe(NO ₃ ) ₃ ·9H The amount of ₂ O added was 2 mmol; the reaction temperature was 180 °C, the reaction time was 12 h, and the drying temperature was 80 °C.

In the step 2), the dosage of Fe(NO ₃ ) ₃ ·9H ₂ O is 200 mg; the impregnation time is 2 h; the drying temperature is 80° C.; the calcination temperature is 500° C., and the calcination time is 1 h.

The micromotor photocatalyst is used for catalyzing degradation of dye wastewater; under the participation of H ₂ O ₂ , simulating ultraviolet light irradiation conditions catalyzes degradation of dye wastewater.

Said, the organic matter concentration in the dye wastewater is 5mg/L, the dosage of the micromotor photocatalyst is 1g/L, the volume ratio of H ₂ O ₂ to the dye solution is 1:50, and the simulated ultraviolet light irradiation time is 1-45min.

Said, the concentration of H ₂ O ₂ is 30%.

Example 3

_A micromotor photocatalyst, α _{- Fe2O3 -} ZnFe2O4 micromotor photocatalyst microspheres are synthesized by a solvothermal method, wherein the diameter of the _ZnFe2O4 hollow microspheres is 0.4-0.8 μm, and the sheet _- like α- _Fe2O3 and _Mn2O3 nanoparticles _were grown _{on ZnFe2O4} microspheres _.

Said, the particle size of the α-Fe ₂ O ₃ -ZnFe ₂ O ₄ micromotor photocatalyst microspheres is 0.5-1 μm.

A preparation method of a micromotor photocatalyst is prepared by the following steps:

1) Add Zn(CH ₃ COO) ₂ · 2H ₂ O and Fe(NO ₃ ) ₃ · 9H ₂ O to the mixed solution, stir magnetically for 10 minutes, then add to the reaction kettle for reaction, cool down to room temperature after completion, and wash with distilled water for 3 second, drying to obtain the precursor of ZnFe ₂ O ₄ hollow microspheres;

2) Take 5 mL of 50% manganese nitrate solution and dilute it to 15 mL with distilled water to obtain a dilute solution of manganese nitrate; add Fe(NO ₃ ) ₃ 9H ₂ O to the dilute manganese nitrate solution and mix well, then add 0.5 g of ZnFe ₂ O _4. The precursor of the hollow microspheres is impregnated, filtered, dried, calcined, and cooled to room temperature to obtain a micromotor photocatalyst.

In the step 1), the mixed solution was prepared from 18 mL of glycerol and 60 mL of isopropanol; the addition amount of Zn(CH ₃ COO) ₂ ·2H ₂ O was 1 mmol; Fe(NO ₃ ) ₃ ·9H The amount of ₂ O added was 2 mmol; the reaction temperature was 180 °C, the reaction time was 12 h, and the drying temperature was 80 °C.

In the step 2), the dosage of Fe(NO ₃ ) ₃ ·9H ₂ O is 200 mg; the impregnation time is 2 h; the drying temperature is 80° C.; the calcination temperature is 500° C., and the calcination time is 1 h.

The micromotor photocatalyst is used for catalyzing degradation of dye wastewater; under the participation of H ₂ O ₂ , simulating ultraviolet light irradiation conditions catalyzes degradation of dye wastewater.

Said, the organic matter concentration in the dye wastewater is 5mg/L, the dosage of the micromotor photocatalyst is 1g/L, the volume ratio of H ₂ O ₂ to the dye solution is 1:50, and the simulated ultraviolet light irradiation time is 1-45min.

Said, the concentration of H ₂ O ₂ is 30%.

test case

Figure 1 is a graph showing the degradation of methylene blue by the micromotor photocatalyst prepared in Examples 1-3 under simulated ultraviolet light. The methylene blue solution was used to simulate organic pollutants in dye wastewater, and the degradation effect of the micromotor photocatalyst prepared in Examples 1-3 under simulated ultraviolet light was tested. The method is as follows: take 0.05g of micromotor photocatalyst and put it into 50mL of 5mg/L methylene blue solution, and then place it in a dark environment for 30min until the adsorption equilibrium. After the adsorption was saturated, 1 mL of 30% H ₂ O ₂ was added to the methylene blue solution, and UV-Fenton reaction was carried out under the irradiation of a 500W mercury lamp. Centrifuge at 4000 r/min for 5 min, measure the absorbance of methylene blue solution under different catalytic time with a spectrophotometer and convert it into concentration to characterize the degradation effect. It can be seen from the figure that the degradation rates of the micromotor photocatalysts prepared in Examples 1-3 of the present invention to methylene blue are 93.9%, 96.6% and 98.9% respectively at 45min, indicating that the micromotor photocatalysts prepared in Examples 1-3 Methylene blue dyes all have efficient catalytic effects and can be used for efficient treatment of dye wastewater.

FIG. 2 is the SEM image, EDS spectrum, TEM, HRTEM and mapping photos of the micromotor photocatalyst prepared in Example 3. FIG. In the figure, (a), (b) and (c) are the SEM images of the micromotor photocatalyst. It can be seen from the figure that the prepared α-Fe ₂ O ₃ -ZnFe ₂ O ₄ micromotor photocatalyst microspheres are dispersed Uniform, flower-like spherical shape, about 0.5-1 μm in diameter. (d) is the EDS spectrum of the micromotor photocatalyst. Through analysis, the sample contains elements such as Zn, Fe, Mn, O, and the molar ratio of Zn:Fe:Mn:O=5.19:37.63:7.94:49.24, which is consistent with The expected stoichiometry matches. (e) is the TEM image of the micromotor photocatalyst. It can be seen that the ZnFe ₂ O ₄ and Mn ₂ O ₃ nanoparticles correspond to the positions of the small black dots on them, and the α-Fe ₂ O ₃ appears as nanosheets in the figure. , which is consistent with the results obtained in the SEM images, which indirectly proves the successful synthesis of the micromotor photocatalyst target material. (f) is the HRTEM image of the micromotor photocatalyst. It can be seen that 0.487 nm and 0.298 nm correspond to the (111) and (220) crystal planes of ZnFe ₂ O ₄ , respectively, and 0.270 nm corresponds to the (104) plane of α-Fe ₂ O ₃ . ) plane, 0.277 nm corresponds to the (104) plane of Mn ₂ O ₃ . (gj) are the corresponding micromotor photocatalyst mapping pictures, demonstrating that O, Zn, Fe, and Mn coexist in the α-Fe ₂ O ₃ -ZnFe ₂ O ₄ micromotor photocatalyst microspheres.

FIG. 3 is the XRD curve of the micromotor photocatalyst prepared in Example 3. FIG. It can be seen from the XRD pattern that the sample is composed of ZnFe ₂ O ₄ , α-Fe ₂ O ₃ and Mn ₂ O ₃ .

FIG. 4 is a SEM image of the ZnFe ₂ O ₄ hollow microspheres prepared in Example 3. FIG. It can be seen from the figure that ZnFe ₂ O ₄ is a hollow microsphere with relatively dispersed and uniform size. The prepared ZnFe ₂ O ₄ hollow microspheres have a diameter of about 0.4-0.8um, and each hollow microsphere is assembled from nanoparticles.

Figure 5 shows the hysteresis loop of the micromotor photocatalyst prepared in Example 3 at room temperature, ranging from -10KOe to 10KOe, the saturation magnetization is 1.37emug ^-1 , the remanence is 1.72×10-3emug ^-1 , the coercivity is 0.62Oe. It can be seen from the figure that the hysteresis loop of the micromotor photocatalyst microspheres is a classic S-shaped curve, which is superparamagnetic.

FIG. 6 is the UV-Vis spectra of the micromotor photocatalyst prepared in Example 3 for methylene blue after different catalysis times. It can be seen from the figure that there is a maximum peak at 664 nm, and with the increase of the photo-Fenton time, the peaks of methylene blue decrease obviously, and almost completely disappear after 45 minutes.

Claims (5)

1. a micromotor photocatalyst is characterized in that, with solvothermal synthesis α-Fe ₂ O ₃ -ZnFe ₂ O ₄ micro motor photocatalyst microsphere, wherein ZnFe ₂ O ₄ The diameter of the hollow microsphere is 0.4-0.8 μm, sheet-like α-Fe ₂ O ₃ and Mn ₂ O ₃ nanoparticles were grown on ZnFe ₂ O ₄ microspheres; the described micromotor photocatalyst was prepared by the following steps: 1) Add Zn(CH ₃ COO) ₂ · 2H ₂ O and Fe(NO ₃ ) ₃ · 9H ₂ O to the mixed solution, stir magnetically for 10 minutes, then add to the reaction kettle for reaction, cool down to room temperature after completion, and wash with distilled water for 3 second, drying to obtain the precursor of ZnFe ₂ O ₄ hollow microspheres; 2) Take 3-5mL of 50% manganese nitrate solution and dilute it to 15mL with distilled water to obtain a manganese nitrate dilute solution; add Fe(NO ₃ ) ₃ 9H ₂ O to the manganese nitrate dilute solution and mix well, then add 0.5g of ZnFe ₂ O ₄ hollow microsphere precursor, impregnated, filtered, dried, calcined, cooled to room temperature to obtain a micromotor photocatalyst; In the step 1), the mixed solution was prepared from 18 mL of glycerol and 60 mL of isopropanol; the addition amount of Zn(CH ₃ COO) ₂ ·2H ₂ O was 1 mmol; Fe(NO ₃ ) ₃ ·9H The amount of ₂ O added was 2 mmol; the reaction temperature was 180°C, the reaction time was 12h, and the drying temperature was 80°C; In the step 2), the dosage of Fe(NO ₃ ) ₃ ·9H ₂ O is 200 mg; the impregnation time is 2 h; the drying temperature is 80° C.; the calcination temperature is 500° C., and the calcination time is 1 h. 2 . The micromotor photocatalyst according to claim 1 , wherein the particle size of the α-Fe ₂ O ₃ -ZnFe ₂ O ₄ micromotor photocatalyst microspheres is 0.5-1 μm. 3 . 3. An application of the micromotor photocatalyst according to claim 1, wherein the micromotor photocatalyst is used to catalyze the degradation of dye waste water; under the participation of H ₂ O ₂ , the catalyzed degradation of dyestuff is carried out by simulating ultraviolet light irradiation conditions waste water. 4. application according to claim 3, is characterized in that, in the described dye waste water, organic matter concentration is 5mg/L, and the consumption of micromotor photocatalyst is 1g/L, H ₂ O ₂ and the volume ratio of dye solution 1: 50, the simulated ultraviolet light irradiation time is 1-45min. The application according to claim 3, wherein the concentration of the H ₂ O ₂ is 30%.

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