阅读说明：本技术 一种含ɑ-MnO2的光催化体系、其制备方法及应用 (alpha-MnO-containing2Photocatalytic system, preparation method and application thereof ) 是由 李胜英 冯建海 姚东梅 陆俊宇 韦衍学 吴英月 苏志恒 于 2020-12-22 设计创作，主要内容包括：本发明提供一种含ɑ-MnO-2的光催化体系、其制备方法及应用,属于光催化剂技术领域。所述光催化体系包括ɑ-MnO-2以及NaHSO-4,NaHSO-4与ɑ-MnO-2的质量比为0.05-1:1；ɑ-MnO-2通过以下方法制备：将KMnO-4溶于去离子水中,在搅拌下滴入含MnSO-4·H-2O的水溶液中,得混合浆料,转移到聚四氟乙烯内衬的不锈钢高压釜中,于烘箱中130-145℃下保温10-13h；待混合浆料冷却后抽滤洗涤,将所得产品于烘箱中干燥,在马弗炉中280-320℃的空气氛围下煅烧1.5-2.5h,即得ɑ-MnO-2。本发明具有较高的光催化效率,对多种有机物有明显的降解效果,降解效率高,体系操作简单。(The invention provides a composition containing alpha-MnO 2 Belonging to the technical field of photocatalysts. The photocatalytic system comprises alpha-MnO 2 And NaHSO 4 ，NaHSO 4 And alpha-MnO 2 The mass ratio of (A) to (B) is 0.05-1: 1; alpha-MnO 2 The preparation method comprises the following steps: mixing KMnO 4 Dissolving in deionized water, and adding MnSO dropwise under stirring 4 ·H 2 Obtaining mixed slurry in the water solution of O, transferring the mixed slurry into a stainless steel high-pressure kettle with a polytetrafluoroethylene lining, and preserving the heat for 10-13h at the temperature of 130-145 ℃ in an oven; cooling the mixed slurry, carrying out suction filtration and washing, drying the obtained product in an oven, calcining the dried product in a muffle furnace at the temperature of 280-320 ℃ in an air atmosphere for 1.5-2.5h to obtain alpha-MnO 2 . The invention has higher photocatalysis efficiency, obvious degradation effect on various organic matters, high degradation efficiency and simple system operation.)

1. alpha-MnO-containing₂Characterized in that: comprising alpha-MnO₂And NaHSO₄。

2. The alpha-MnO-containing system of claim 1, wherein the alpha-MnO is a solution of₂Characterized in that: the alpha-MnO₂The crystal form is a specific crystal form and is prepared by the following preparation method: mixing KMnO₄Dissolving in deionized water, and dripping MnSO under magnetic stirring₄·H₂Obtaining mixed slurry in the water solution of O, transferring the mixed slurry into a stainless steel autoclave with a polytetrafluoroethylene lining, and preserving the heat for 10-13h at the temperature of 130-; after the mixed slurry is cooled, filtering and washing, drying the obtained solid product in an oven, and then calcining for 1.5-2.5h in a muffle furnace in the air atmosphere of 280-320 ℃ to obtain the productɑ-MnO₂。

3. The alpha-MnO-containing system of claim 2, wherein the alpha-MnO is a manganese-₂Characterized in that: the KMnO₄The solid-to-liquid ratio of the deionized water is 1g to 20-30 ml; MnSO₄·H₂O and KMnO₄The molar ratio of (A) to (B) is 1: 2-3.5.

4. The alpha-MnO-containing system of claim 2, wherein the alpha-MnO is a manganese-₂Characterized in that: the drying temperature is 75-90 ℃, and the drying time is 10-14 h.

5. The alpha-MnO-containing system of claim 1, wherein the alpha-MnO is a solution of₂Characterized in that: the NaHSO₄And alpha-MnO₂The mass ratio of (A) to (B) is 0.05-1: 1.

6. The alpha-MnO-containing product of any one of claims 1 to 5, wherein the alpha-MnO is a solution containing alpha-MnO₂The method for producing a photocatalytic system according to (1), characterized by comprising the steps of:

(1) preparation of alpha-MnO₂: mixing KMnO₄Dissolving in deionized water, and dripping MnSO under magnetic stirring₄·H₂O aqueous solution to obtain mixed slurry, transferring the mixed slurry into a stainless steel autoclave with a polytetrafluoroethylene lining, and preserving the heat for 10-13h at the temperature of 145 ℃ in an oven; cooling the mixed slurry, performing suction filtration and washing, drying the obtained solid product in an oven, and calcining the dried solid product in a muffle furnace at the temperature of 280-320 ℃ for 1.5-2.5h in the air atmosphere to obtain the alpha-MnO₂；

(2) Will alpha-MnO₂And NaHSO₄And (5) subpackaging respectively.

7. The alpha-MnO-containing product of any one of claims 1 to 5, wherein the alpha-MnO is a solution containing alpha-MnO₂The use of a photocatalytic system according to (1), characterized in that: the photocatalytic system is used in the degradation of organic contaminated wastewater.

8. The alpha-MnO-containing system of claim 7₂The use of a photocatalytic system according to (1), characterized in that: the specific application method comprises the step of adding a certain amount of alpha-MnO into the organic polluted wastewater₂Simultaneously adding a certain amount of NaHSO₄And applying illumination to the organic matter polluted wastewater for more than 0.5h to obtain an obvious degradation effect.

9. The alpha-MnO-containing system of claim 8₂The use of a photocatalytic system according to (1), characterized in that: the alpha-MnO₂The concentration of the waste water is 0.5g/L-3 g/L.

10. The alpha-MnO-containing system of claim 8₂The use of a photocatalytic system according to (1), characterized in that: the light wavelength range of the illumination is 200nm-800 nm.

Technical Field

The invention relates to a photocatalytic degradation treatment technology of organic matter wastewater, relates to the technical field of photocatalysts, and particularly relates to a photocatalyst containing alpha-MnO₂A photocatalytic system, a preparation method and application thereof.

Background

In industrial processes, a large amount of organic waste water is discharged, and organic substances in the organic waste water exist in a water system in a suspended or dissolved state and are difficult to degrade. Most organic matters are toxic and harmful, cause harm to other organisms in the water body, can be continuously degraded under the action of microorganisms and other organisms, but oxygen needs to be consumed in the decomposition process, the dissolved oxygen in the water is reduced, and the growth of other organisms can also be influenced.

In the prior art, it is organicThe method for treating the waste water includes biodegradation, adsorption, photocatalysis and the like. The related research of photodegradation of organic matters is more, and the organic matters are directly degraded into CO in the photodegradation process₂And H₂O and the like, is green and environment-friendly, does not need secondary treatment, and has wide research prospect.

The photocatalytic degradation technology needs the support of a photocatalytic material, and a common photocatalytic material is TiO₂ZnO or correspondingly doped metal oxides, etc. The mechanism of photocatalysis is that ultraviolet light or visible light irradiates a photocatalysis material, and correspondingly generates holes (h)⁺) And electron (e)^-) And OH is reacted with^-And O₂Isooxidation-reduction to form OH and O₂ ^-And the like corresponding radicals. These radicals are highly reactive and readily reduce organic species to CO₂And H₂And O. The photocatalysis can be carried out at room temperature, but the problems of long illumination time and low photocatalysis efficiency exist. MnO₂Can also be used in the field of photocatalysis, but also has the problems of low photocatalysis efficiency and the like.

The common method for solving the problem of low catalytic efficiency of the photocatalyst is to modify the substrate catalyst by carrying out metal, nonmetal loading or composite loading of other compounds, or to add some cocatalyst such as H₂O₂、O₃Persulfate (Na)₂S₂O₈) And the like are modified in cooperation with the photocatalyst. MnO₂The photocatalyst has certain photocatalysis, but the photocatalyst has the problems of low photocatalysis efficiency and the like. Therefore, there is room for further research and development in the field of photocatalyst technology.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an a-MnO-containing solution₂The alpha-MnO with a nanowire morphology is prepared by the photocatalytic system₂And with NaHSO₄The composite system is formed cooperatively, so that the photocatalytic efficiency is high, the degradation effect on various organic matters is obvious, the degradation efficiency is high, and the system is simple to operate.

The technical scheme for realizing the aim of the invention is as follows:

alpha-MnO 2-containing photocatalystComprises alpha-MnO₂And NaHSO₄(ii) a In the invention, a small amount of NaHSO is added₄Namely, can be made to alpha-MnO₂The photocatalytic efficiency of (A) plays a synergistic role, but preferably the NaHSO₄And alpha-MnO₂The mass ratio of (A) to (B) is 0.05-1:1, and the synergistic effect is most obvious.

In the present invention, preferably, the α -MnO is₂The crystal form is a specific crystal form and is prepared by the following preparation method: mixing KMnO₄Dissolving in deionized water, and dripping MnSO under magnetic stirring₄·H₂Obtaining mixed slurry in the water solution of O, transferring the mixed slurry into a stainless steel autoclave with a polytetrafluoroethylene lining, and preserving the heat for 10-13h at the temperature of 130-; cooling the mixed slurry, performing suction filtration and washing, drying the obtained solid product in an oven, and calcining the dried solid product in a muffle furnace at the temperature of 280-320 ℃ for 1.5-2.5h in the air atmosphere to obtain the alpha-MnO₂It is in the shape of a nanowire.

In the present invention, preferably, the KMnO₄The solid-to-liquid ratio of the deionized water is 1g to 20-30 ml; MnSO₄·H₂O and KMnO₄The molar ratio of (A) to (B) is 1: 2-3.5.

In the invention, preferably, the drying temperature is 75-90 ℃, and the drying time is 10-14 h.

Another object of the present invention is to provide an alpha-MnO-containing alloy₂The preparation method of the photocatalytic system comprises the following steps:

(1) preparation of alpha-MnO₂: mixing KMnO₄Dissolving in deionized water, and dripping MnSO under magnetic stirring₄·H₂Obtaining mixed slurry in the water solution of O, transferring the mixed slurry into a stainless steel autoclave with a polytetrafluoroethylene lining, and preserving the heat for 10-13h at the temperature of 130-; cooling the mixed slurry, performing suction filtration and washing, drying the obtained solid product in an oven, calcining the dried solid product in a muffle furnace at the temperature of 280-320 ℃ in the air atmosphere for 1.5-2.5h to obtain the alpha-MnO₂；

(2) Will alpha-MnO₂And NaHSO₄And (5) subpackaging respectively. When in use, the components are respectively added.

Another object of the present invention is to providealpha-MnO-containing₂The application of the photocatalytic system is to use the photocatalytic system in the degradation of organic polluted wastewater.

The specific application method comprises the following steps: adding a certain amount of alpha-MnO into organic polluted wastewater₂Simultaneously adding a certain amount of NaHSO₄And applying illumination to the organic matter polluted wastewater for more than 0.5h to obtain an obvious degradation effect.

Preferably, the α -MnO is optimized for optimal photocatalytic effect₂The concentration of the waste water is 0.5g/L-3 g/L.

The photocatalytic system of the present invention has weak dependence on light source, but has better effect of applying light with wavelength in the range of 200-800 nm.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that: alpha-MnO of specific crystal form is used in the invention₂With NaHSO₄A strong oxidation-reduction system is constructed, and the degradation effect on various organic matters is obvious. Compared with the traditional Fenton-like photocatalysis technology and the like, the method has the advantages of low treatment cost, mild reaction system, no obvious secondary pollution and high cyclic utilization rate. The invention has very wide commercial application value for industrial organic pollution wastewater.

Drawings

FIG. 1 shows alpha-MnO prepared in example 2 (scheme a)₂X-ray diffraction patterns of;

FIG. 2 shows alpha-MnO prepared in example 2 (scheme a)₂Scanning electron microscope images of;

FIG. 3 is a graph of the photocatalytic degradation rate of the photocatalytic system prepared in example 2 (scheme a) as a function of time;

FIG. 4 shows alpha-MnO prepared according to scheme b₂X-ray diffraction patterns of;

FIG. 5 shows alpha-MnO prepared according to scheme b₂Scanning electron microscope images of;

FIG. 6 is a graph showing the photocatalytic degradation rate of the photocatalytic system prepared in the scheme b as a function of time;

FIG. 7 shows alpha-MnO prepared according to scheme c₂X-ray diffraction pattern of

FIG. 8 shows alpha-MnO prepared according to scheme c₂Scanning electron microscope image of

FIG. 9 shows alpha-MnO prepared according to scheme c₂A graph of the photocatalytic degradation rate of the photocatalytic system changing with time;

FIG. 10 shows α -MnO₂Graph comparing the photocatalytic degradation ability synergistically with different inorganic salts.

Detailed Description

In order that the invention may be more clearly expressed, the invention will now be further described by way of specific examples.

First, preparation example

Example 1

alpha-MnO-containing₂Comprising alpha-MnO₂And NaHSO₄(ii) a And NaHSO₄And alpha-MnO₂The mass ratio of (A) to (B) is 0.05: 1.

alpha-MnO-containing₂Preparation of the photocatalytic system of (a): (1) 1gKMnO₄Dissolving in 20ml deionized water, and dripping into a solution containing 0.53g MnSO under magnetic stirring₄·H₂Obtaining mixed slurry by using 15ml of water solution of O, transferring the mixed slurry into a stainless steel autoclave with a polytetrafluoroethylene lining, and keeping the temperature for 13 hours in an oven at 130 ℃; cooling the mixed slurry, performing suction filtration and washing, drying the obtained solid product in a 75 ℃ oven for 14h, and calcining the dried solid product in a muffle furnace at 280 ℃ in an air atmosphere for 2.5h to obtain the alpha-MnO₂It is in the shape of a nanowire.

(2) Will alpha-MnO₂And NaHSO₄Subpackaging respectively, and adding respectively when in use.

alpha-MnO-containing₂The application of the photocatalytic system refers to that the photocatalytic system is used for degrading organic polluted wastewater. The specific method comprises the following steps: adding a certain amount of alpha-MnO into organic pollution wastewater₂Using alpha-MnO₂When the concentration of the wastewater is 0.5g/L, a certain amount of NaHSO is added at the same time₄So that NaHSO₄And alpha-MnO₂The mass ratio of the organic matter-polluted wastewater is 0.05:1, and the organic matter-polluted wastewater is irradiated by light with the wavelength ranging from 200nm to 800nm for more than 0.5h, so that an obvious degradation effect can be seen.

Example 2

alpha-MnO-containing₂Comprising alpha-MnO₂And NaHSO₄(ii) a And NaHSO₄And alpha-MnO₂The mass ratio of (A) to (B) is 0.8: 1.

Preparation of a photocatalytic system containing alpha-MnO 2: (1) 1.0g of KMnO₄Dissolving in 25ml deionized water, and dripping into a solution containing 0.4g MnSO under magnetic stirring₄·H₂Obtaining mixed slurry by using 18ml of water solution of O, transferring the mixed slurry into a stainless steel autoclave with a polytetrafluoroethylene lining, and preserving heat for 12 hours in an oven at the temperature of 140 ℃; cooling the mixed slurry, carrying out suction filtration and washing, drying the obtained solid product in an oven at 80 ℃ for 12h, and calcining the dried solid product in a muffle furnace at 300 ℃ for 2h in an air atmosphere to obtain the alpha-MnO₂It is in the shape of a nanowire.

(2) Will alpha-MnO₂And NaHSO₄Subpackaging respectively, and adding respectively when in use.

alpha-MnO-containing₂The application of the photocatalytic system refers to that the photocatalytic system is used for degrading organic polluted wastewater. The specific method comprises the following steps: adding a certain amount of alpha-MnO into organic pollution wastewater₂Using alpha-MnO₂When the concentration of the wastewater is 1.25g/L, a certain amount of NaHSO is added at the same time₄So that NaHSO₄And alpha-MnO₂The mass ratio of the organic matter polluted wastewater is 0.8:1, the organic matter polluted wastewater is irradiated by light with the wavelength ranging from 200nm to 800nm for more than 0.5h, and the obvious degradation effect can be seen.

Example 3

alpha-MnO-containing₂Comprising alpha-MnO₂And NaHSO₄(ii) a And NaHSO₄And alpha-MnO₂The mass ratio of (A) to (B) is 1: 1.

alpha-MnO-containing₂Preparation of the photocatalytic system of (a): (1) 1.0g of KMnO₄Dissolving in 30ml deionized water, and dripping into a solution containing 0.3g MnSO under magnetic stirring₄·H₂O in 20ml of water solution to obtain mixed slurry, transferring the mixed slurry into a stainless steel autoclave with a polytetrafluoroethylene lining, and preserving the heat for 10 hours in an oven at 145 ℃; after the mixed slurry is cooled, filtering and washing the mixed slurry to obtainDrying the obtained solid product in an oven at 90 ℃ for 10h, calcining the dried solid product in a muffle furnace at 320 ℃ for 1.5h in the air atmosphere to obtain the alpha-MnO₂It is in the shape of a nanowire.

(2) Will alpha-MnO₂And NaHSO₄Subpackaging respectively, and adding respectively when in use.

alpha-MnO-containing₂The application of the photocatalytic system refers to that the photocatalytic system is used for degrading organic polluted wastewater. The specific method comprises the following steps: adding a certain amount of alpha-MnO into organic pollution wastewater₂Using alpha-MnO₂When the concentration of the wastewater is 0.5g/L-3g/L, a certain amount of NaHSO is added at the same time₄So that NaHSO₄And alpha-MnO₂The mass ratio of the organic matter polluted wastewater is 1:1, the organic matter polluted wastewater is irradiated by light with the wavelength ranging from 200nm to 800nm for more than 0.5h, and then the obvious degradation effect can be seen.

Analysis of the x-ray diffraction pattern of the product obtained in examples 1 to 3 revealed that the product was alpha-MnO₂Wherein the x-ray diffraction pattern of example 2 is shown in figure 1; the microscopic morphology of the scanning electron microscope shows that the prepared MnO is₂Is in the shape of a nanowire, wherein the scanning electron micrograph of example 2 is shown in figure 2.

Secondly, photocatalytic degradation test:

in order to better express the advantages of the present application, some research experiments on photocatalytic degradation are described as follows.

1. The photocatalytic degradation method comprises the following steps:

the application experiment of the product prepared by the example for catalytically degrading organic matters by taking methyl orange, rhodamine B and tetracycline hydrochloride organic matters as examples is described as follows: adding a photocatalyst into 40mL of methyl orange solution, rhodamine B solution and tetracycline hydrochloride solution with the concentration of 35mg/L respectively, standing in the dark for 30min to achieve adsorption/desorption balance, starting visible light irradiation, moving 2mL of solution from the solution every 20min, adding 1mL of methanol solution, performing suction filtration by using a filter head, filtering solid particles, putting the filtrate into a cuvette, and measuring the absorbance of the solution under the characteristic wavelength of an organic substance (methyl orange: 464nm, rhodamine B: 554nm and tetracycline hydrochloride: 358nm) respectively and comparing the absorbance with the absorbance of the initial solution.

The photodegradation ratio (D) was calculated according to the following formula: d ═ C₀-C_t)/C₀*100％＝(A₀－A_t)/A₀100% of C, wherein₀Is the initial concentration of the solution, C_tThe concentration of the solution after the illumination time is t; c₀Initial absorbance of the solution, C_tThe absorbance of the solution after the illumination time is t.

2. alpha-MnO of different crystal forms₂Test of catalytic Effect of photocatalyst System

Scheme a: test group a photocatalytic test was performed using the photocatalytic system prepared in example 2, and the amount of the catalyst system added was the same as in example 2; comparative group a prepared by example 2₂Performing photocatalytic test, alpha-MnO₂The addition amount of alpha-MnO of test group a₂The addition amount of (A) is the same; the results of the photocatalytic degradation capability test on the three organic matters are shown in figure 3.

Scheme b: test group b prepared alpha-MnO by the following method₂(ii) a By using NaHSO₄And alpha-MnO₂Adding the materials according to the mass ratio of 0.8:1, wherein the adding amount is the same as that of the catalyst system in the example 2, and performing a photocatalytic test as a photocatalytic system; alpha-MnO obtained by using test group b as comparison group b₂Performing photocatalytic test, alpha-MnO₂The addition amount of alpha-MnO of test group b₂The addition amount of (A) is the same; the results of the photocatalytic degradation capability test on the three organic matters are shown in fig. 6;

alpha-MnO in test group b₂The preparation method comprises the following steps: adding 8mmol K₂S₂O₈、8mmolMnSO₄·H₂O and 8mmolK₂SO₄Dissolved in 60mL of deionized water, and 98 wt% H was added₂SO₄The solution was 2 mL. The solution was then transferred to a teflon lined stainless steel autoclave and heated in an oven at 140 ℃ for 12 hours. Finally, the a-MnO was collected by centrifugation₂Precipitating the nanoparticles, and drying at 105 deg.C. The analysis of the x-ray diffraction pattern of the product obtained shows itIs alpha type MnO₂As shown in fig. 4. The microscopic morphology of the scanning electron microscope shows that the prepared MnO is₂Is needle-shaped and gathered into dandelion flower shape, as shown in fig. 5.

Test group c: test group c prepared alpha-MnO by the following method₂(ii) a By using NaHSO₄And alpha-MnO₂The catalyst is added according to the mass ratio of 0.8:1, the adding amount is the same as that of the catalyst system in the example 2, and the catalyst is used as a photocatalytic system to carry out a photocatalytic test; the comparison group c adopts alpha-MnO obtained by the test group c₂Performing photocatalytic test, alpha-MnO₂The addition amount of alpha-MnO in test group c₂The addition amount of (A) is the same; the results of the photocatalytic degradation capability test on the three organic matters are shown in FIG. 9.

alpha-MnO in test group c₂The preparation method comprises the following steps: adding 1.35g of potassium permanganate and 3.0ml of hydrochloric acid (37%) into 120ml of deionized water, dissolving the potassium permanganate and the hydrochloric acid, magnetically stirring the mixture for 30min, transferring the mixture into a high-pressure reaction kettle, putting the reaction kettle into a drying box, heating the mixture to 160 ℃, and reacting the mixture for 12 hours; naturally cooling to room temperature, filtering the obtained suspension, washing until the pH value is not changed, and drying the obtained sample in a drying oven at 80 ℃ for 24h to obtain the product. The analysis result of the x-ray diffraction pattern of the obtained product shows that the product is alpha type MnO₂As shown in fig. 7. The microscopic morphology of the scanning electron microscope shows that the prepared MnO is₂It is needle-shaped and gathered into chestnut shell shape, as shown in FIG. 8.

As can be seen from the results of the photocatalytic degradation capability tests in fig. 3, 6, and 9, the a type MnO prepared by the three schemes₂All have certain catalytic degradation capacity, and the alpha type MnO prepared by the three schemes₂In synergy of NaHSO₄Then, the photocatalytic degradation rate is obviously increased. Description of NaHSO₄The addition of (2) is beneficial to the improvement of the photocatalytic efficiency. And the alpha type MnO prepared by the scheme a (the best scheme of the invention)₂In synergy of NaHSO₄And then, the degradation rates of methyl orange solution, rhodamine B solution and tetracycline hydrochloride solution are highest, and alpha type MnO prepared by schemes B and c is obtained₂In synergy of NaHSO₄Later, the degradation rate of the methyl orange solution is higher, but the degradation rates of the rhodamine B solution and the tetracycline hydrochloride solution are improvedThe lifting effect is obviously inferior to that of the scheme a; description of preparation of scheme a₂In synergy of NaHSO₄The photocatalytic effect is then optimal.

3. Test of Effect of ions on photocatalytic Properties

alpha-MnO prepared as in example 2₂The catalyst is a main body of the catalyst, the adding amount of the catalyst is 0.05 g, the adding amount of other inorganic salts is 0.04g, and the using amount of methyl orange is 40mL, and the concentration is 35 mg/L. Other inorganic salts are discussed, including Na₂SO₄、NaHSO₃、NaHSO₄、MnSO₄、NaNO₃、NaH₂PO₄And alpha-MnO₂The result of the synergistic effect on the photocatalytic degradation of methyl orange is shown in fig. 10. It can be seen that the alpha-MnO prepared by the present invention₂With NaHSO₄After the synergistic effect, the photocatalytic degradation rate is far higher than that of other groups, and the photocatalytic effect is optimal.

The above description is intended to describe in detail the preferred embodiments of the present invention, but the embodiments are not intended to limit the scope of the claims of the present invention, and all equivalent changes and modifications made within the technical spirit of the present invention should fall within the scope of the claims of the present invention.