阅读说明：本技术 一种有机化二氧化硅负载PMoW多酸光催化材料及其制备方法和应用 (Organic silicon dioxide loaded PMoW polyacid photocatalytic material and preparation method and application thereof ) 是由 程峰 张国林 丁静亚 陈冬斌 许琦 于 2021-10-29 设计创作，主要内容包括：本发明公开了一种有机化二氧化硅负载PMoW多酸光催化材料,其于由PMoW多酸和有机化二氧化硅微球组成,PMoW多酸负载在有机化二氧化硅微球表面,所述PMoW多酸为H-(3)PMonW-((12-n))O-(40)·xH-(2)O,其中1<n<12,有机化二氧化硅微球和PMoW多酸的质量比为1：0.1～1:2,所述有机化二氧化硅负载PMoW多酸光催化材料的孔隙率为62%。(The invention discloses an organic silicon dioxide loaded PMoW polyacid photocatalytic material, which consists of PMoW polyacid and organic silicon dioxide microspheres, wherein the PMoW polyacid is loaded on the surfaces of the organic silicon dioxide microspheres, and the PMoW polyacid is H 3 PMonW （12‑n） O 40 ·xH 2 O, wherein 1<n<12, the mass ratio of the organic silica microspheres to the PMoW polyacid is 1: 0.1-1: 2, wherein the porosity of the organic silicon dioxide loaded PMoW polyacid photocatalytic material is 62%.)

1. An organic silicon dioxide loaded PMoW polyacid photocatalytic material is characterized by consisting of PMoW polyacid and organic silicon dioxide microspheres, wherein the PMoW polyacid is loaded on the surfaces of the organic silicon dioxide microspheres, and the PMoW polyacid is H₃PMonW_（12-n）O₄₀·xH₂O, wherein 1<n<12, the mass ratio of the organic silica microspheres to the PMoW polyacid is 1: 0.1-1: 2.

2. The organic silica-supported PMoW polyacid photocatalytic material of claim 1, characterized in that the porosity of the organic silica-supported PMoW polyacid photocatalytic material is 62%.

3. A method for preparing an organic silica-supported PMoW polyacid photocatalytic material according to claim 1 or 2, comprising the steps of:

step 1: preparing the silicon dioxide microspheres: dissolving 0.3g of tetraethoxysilane and 1ml of hexadecyl trimethyl ammonium bromide in an ethanol water solution, dropwise adding ammonia water to adjust the pH to be =8, stirring for 48 hours at 50 ℃, cooling the mixture to room temperature, centrifugally separating slurry, washing for 3 times by using distilled water, then freeze-drying, placing in a quartz crucible, and calcining for 6 hours at 773K to obtain silicon dioxide microspheres;

step 2: organizing the silica microspheres: ultrasonically dispersing the silicon dioxide microspheres prepared in the step 1 in an N, N-dimethylformamide solution, adding a silane coupling agent KH-560, adding 1mol/L sodium hydroxide solution to adjust the pH to be =9, stirring at room temperature for 2 hours, transferring the obtained slurry into a polytetrafluoroethylene reaction kettle, reacting at 80 ℃ for 12 hours, centrifugally separating the slurry, washing with distilled water at 80 ℃ for three times, and freeze-drying to obtain organic silicon dioxide microspheres;

and step 3: preparing an organic silicon dioxide loaded PMoW polyacid photocatalytic material: taking 2g of the organic silicon dioxide microspheres prepared in the step 2, and ultrasonically dispersing the organic silicon dioxide microspheres in 62.5ml of deionized water; 2.15 g disodium hydrogen phosphate was dissolved in the solution 12.5 mL deionized water; 8.71 g of sodium molybdate was dissolved in 25ml of deionized water; mixing organic silicon dioxide water solution, disodium hydrogen phosphate water solution and sodium molybdate water solution, stirring at 90 deg.C for 30 min, adding 11.88 g sodium tungstate solution, adding concentrated H₂SO₄Adjusting the pH =1.5, continuously stirring the obtained slurry at 90 ℃ for 8 hours, freeze-drying, washing the obtained solid with 60 ℃ ethanol solution for 3 times, and heating at 300 ℃ for 4 hours to obtain the product, namely the organic silica supported PMoW polyacid composite.

4. The method for preparing an organic silica-supported PMoW polyacid photocatalytic material according to claim 3, characterized in that the conditions of calcination in step 1 are as follows: n with a purity of 99.999%₂The gas flow is 100-200 mL/min, the temperature is raised to 700 ℃ at the speed of 5 ℃/min, and the calcination time is 6 h.

5. The method for preparing an organic silica-supported PMoW polyacid photocatalytic material according to claim 3, wherein 10ml of N, N-dimethylformamide is added per 0.1 g of silica microspheres in step 2; adding silane coupling agent KH-560 with the same mass as the silica microspheres.

6. The method for preparing an organic silica supported PMoW polyacid photocatalytic material according to claim 3, characterized in that the concentration of sodium tungstate solution in step 3 is 0.1 mol/L.

7. Use of the organic silica-supported PMoW polyacid photocatalytic material of claim 1 or 2, for the treatment of wastewater, either industrial wastewater containing organic toxins or aquaculture wastewater containing antibiotics.

Technical Field

The invention belongs to the field of industrial wastewater treatment photocatalytic materials, and particularly relates to an organic silicon dioxide loaded PMoW polyacid photocatalytic material and a preparation method and application thereof.

Background

With the economic development, a large amount of industrial wastewater difficult to degrade is wantonly discharged into the environment, and the water quality pollution caused by the industrial wastewater is an important problem of environmental pollution in China and even the world. The organic wastewater in the pharmaceutical industry and the breeding industry mainly comprises refractory antibiotics, and the wastewater has extremely high hydrophilicity and biological accumulation and has great harm to the health of human beings. The excessive application of chemical fertilizer and pesticide also causes excessive propagation of algae in water, the produced algae toxins further promote the growth of harmful substances in water, and the investigation of epidemic diseases in high liver cancer areas shows that the water polluted by drinking algae toxins is the main reason of liver cancer. In conclusion, the harmless treatment of the refractory organic wastewater is not slow. The treatment process of the refractory organic wastewater mainly comprises a biological method, a physical method and a chemical method. Since microorganisms have their natural disadvantages for the degradation of organic wastewater, biological methods cannot effectively degrade organic pollutants in water. The method for removing the organic matters in the water by the physical method mainly utilizes the adsorption of porous substances on the organic matters in the water, has small effective working area, can not degrade organic pollutants and is easy to form secondary pollutants. Therefore, the harmless degradation of the organic wastewater by using a chemical method has wide application prospect.

At present, the treatment of the industrial wastewater difficult to degrade mainly depends on catalytic oxidative degradation, wherein photocatalysis has unique advantages. The organic matter difficult to degrade is degraded by photocatalysis, and the dependence of the traditional thermal catalytic degradation on energy is overcome. At present, the main problem of photocatalytic applications is the high cost of catalytic materials, mainly due to the dependence of precious metals on the current waste water treatment. The noble metal is expensive, has small specific surface area and is not beneficial to industrial application, so that the key problems of the development of the photocatalysis technology are to find a cheap carrier, improve the metal dispersion degree and improve the electron transmission performance of the catalyst.

The non-noble metal heteropolyacid salt has a relatively stable structure and the capability of rapidly and reversibly transferring electrons, and becomes one of important research directions of the photocatalyst. The nano silicon dioxide is a light porous nano material, is a non-toxic and tasteless inorganic non-metallic material, has a flocculent and reticular quasi-particle structure, is spherical, and has the characteristics of large specific surface area, small density, good dispersion performance and the like. The polyacid catalyst shows excellent wastewater purification ability, and Mo-POM has been recently used as a photocatalyst for catalytic degradation of organic wastewater. But POM/SiO synthesized by traditional dipping method is adopted at present₂The main problem of the composite material is that the heteropoly acid is not firmly combined with the silicon dioxide and is easy to fall off from the silicon dioxide, so that the heteropoly acid is lost in the reaction process.

Disclosure of Invention

Aiming at the defects of the prior art, the invention discloses an organic silicon dioxide loaded PMoW polyacid photocatalytic material, a preparation method and application thereof, and the invention is realized by the following technical scheme:

an organic silica-supported PMoW polyacid photocatalytic material is composed of PMoW polyacid and organic silica microspheres, wherein the PMoW polyacid is supported on the surfaces of the organic silica microspheres, and the PMoW polyacid is H3PMonW (12-n) O₄₀·xH₂O, wherein 1<n<12, the mass ratio of the organic silicon dioxide microspheres to the PMoW polyacid is 1: 0.1-1: 2.

The porosity of the organic silica-supported PMoW polyacid photocatalytic material is 62%.

A preparation method of an organic silicon dioxide loaded PMoW polyacid photocatalytic material comprises the following steps:

step 1: preparing the silicon dioxide microspheres: dissolving 0.3g of tetraethoxysilane and 1ml of hexadecyl trimethyl ammonium bromide in an ethanol water solution, dropwise adding ammonia water to adjust the pH to be =8, stirring for 48 hours at 50 ℃, cooling the mixture to room temperature, centrifugally separating slurry, washing for 3 times by using distilled water, then freeze-drying, placing in a quartz crucible, and calcining for 6 hours at 773K to obtain silicon dioxide microspheres;

step 2: organizing the silica microspheres: ultrasonically dispersing the silicon dioxide microspheres prepared in the step 1 in an N, N-dimethylformamide solution, adding a silane coupling agent KH-560, adding 1mol/L sodium hydroxide solution to adjust the pH to be =9, stirring at room temperature for 2 hours, transferring the obtained slurry into a polytetrafluoroethylene reaction kettle, reacting at 80 ℃ for 12 hours, centrifugally separating the slurry, washing with distilled water at 80 ℃ for three times, and freeze-drying to obtain organic silicon dioxide microspheres;

and step 3: preparing an organic silicon dioxide loaded PMoW polyacid photocatalytic material: taking 2g of the organic silicon dioxide microspheres prepared in the step 2, and ultrasonically dispersing the organic silicon dioxide microspheres in 62.5ml of deionized water; 2.15 g disodium hydrogen phosphate was dissolved in the solution 12.5 mL deionized water; 8.71 g of sodium molybdate was dissolved in 25ml of deionized water; mixing organic silicon dioxide water solution, disodium hydrogen phosphate water solution and sodium molybdate water solution, stirring at 90 deg.C for 30 min, adding 11.88 g sodium tungstate solution, adding concentrated H₂SO₄Adjusting the pH =1.5, continuously stirring the obtained slurry at 90 ℃ for 8 hours, freeze-drying, washing the obtained solid with 60 ℃ ethanol solution for 3 times, and heating at 300 ℃ for 4 hours to obtain the product, namely the organic silica supported PMoW polyacid composite.

The conditions of calcination in step 1 were as follows: n with a purity of 99.999%₂The gas flow is 100-200 mL/min, the temperature is raised to 700 ℃ at the speed of 5 ℃/min, and the calcination time is 6 h.

In the step 2, 10ml of N, N-dimethylformamide is added into every 0.1 g of silicon dioxide microspheres; adding silane coupling agent KH-560 with the same mass as the silica microspheres.

In the step 3, the concentration of the sodium tungstate solution is 0.1 mol/L.

The application of the organic silicon dioxide loaded PMoW polyacid photocatalytic material is used for treating wastewater, wherein the wastewater is industrial wastewater with high organic toxin content (2000 mg/L) or aquaculture wastewater with a large amount of antibiotics (2000 mg/L). Preferably, the wastewater is industrial wastewater with high organic toxin content or aquaculture wastewater containing a large amount of antibiotics.

The invention loads the PMoW heteropoly acid on the organic silicon dioxide spherical core, improves the dispersion degree of the PMoW heteropoly acid, enhances the activity of the PMoW heteropoly acid, simultaneously increases the specific surface area and the porosity of the composite material, and effectively realizes the characteristic of efficiently degrading industrial wastewater pollutants. The invention has the following beneficial effects:

1. the main component PMoW polyacid of the organic silicon dioxide loaded PMoW polyacid photocatalytic material has a unique structure, so that the organic pollutants can be more easily adsorbed; most of metal atoms in the PMoW polyacid are in the highest valence state, the electronegativity is strong, the high oxygen-rich surface endows the PMoW polyacid with strong oxidation capacity, and the PMoW polyacid also shows quick and reversible oxidation-reduction capacity under mild conditions; the unique metal oxygen-containing cluster structure of heteropoly acid makes PMoW polyacid similar to semiconductor (TiO)₂) The surface can generate a large amount of OH free radicals under the condition of illumination, has strong oxidizing property, and can oxidize and degrade organic matters in the industrial wastewater.

2. The organic silicon dioxide loaded PMoW polyacid photocatalytic material is prepared by loading PMoW polyacid on the surface of an organic silicon dioxide microsphere. The surface of the silicon dioxide is organized, the silicon hydroxyl on the surface of the mesoporous silicon dioxide is utilized to directly introduce organic functional groups into the material, and the organic functional groups and the C polyacid are utilized to form more stable combination, so that the service life of the silica-loaded PMoW polyacid in the reaction process is prolonged, and the defects that the heteropolyacid is not firmly combined with the silicon dioxide and is easy to fall off from the silicon dioxide are overcome. The PMoW heteropoly acid is loaded on the organic silicon dioxide spherical core, so that the dispersity of the PMoW heteropoly acid is improved, the activity of the PMoW heteropoly acid is enhanced, the specific surface area and the porosity of the composite material are increased, and the characteristic of efficiently degrading industrial wastewater pollutants is effectively realized. The photocatalytic material obtained by organizing the surface of silicon dioxide and loading PMoW polyacid has a porous echinoid structure, high porosity, large specific surface area and large membrane flux, and has the characteristic of efficiently degrading organic pollutants.

Drawings

FIG. 1 is an XRD pattern of an organic silica supported PMoW polyacid photocatalytic material prepared in example 2;

FIG. 2 is a TEM image of the organized silica microspheres prepared in example 2;

FIG. 3 is an SEM image of an organic silica supported PMoW polyacid photocatalytic material of example 2;

fig. 4 is a graph of the degradation rate of the organic silica-supported PMoW polyacid photocatalytic material prepared in example 2 for degrading erythromycin and algal toxins.

Detailed Description

The present invention will be described in further detail with reference to the following drawings and examples.

Example 1

A preparation method of a silica-supported PMoW polyacid photocatalytic material comprises the following steps:

step 1) preparation of silica microspheres: tetraethoxysilane (CTAB, 0.3 g) and cetyltrimethylammonium bromide (TEOS, 1 mL) were dissolved in an aqueous solution of ethanol (ethanol 103.8mL, distilled water 82.8 mL)), ammonia was added dropwise to adjust pH =8, stirring was performed at 50 ℃ for 48 hours, the mixture was cooled to room temperature, the slurry was centrifuged, and washed with distilled water 3 times; after the obtained product is frozen and dried, the product is placed in a quartz crucible and calcined for 6 hours under 773K to prepare the silicon dioxide microspheres.

Step 2) organizing the silica microspheres: ultrasonically dispersing the silicon dioxide microspheres prepared in the step 1) in an N, N-dimethylformamide solution, adding a certain amount of silane coupling agent KH-560, adding 1mol/L sodium hydroxide solution to adjust the pH to be =9, stirring at room temperature for 2 hours, transferring the obtained slurry into a polytetrafluoroethylene reaction kettle, and reacting at 80 ℃ for 12 hours. Centrifugally separating the slurry, washing with distilled water at 80 ℃ for three times, freezing and drying to obtain the product, namely the organic silicon dioxide microsphere C-SiO₂。

The organic silicon dioxide microsphere C-SiO prepared by the embodiment₂The TEM image of the obtained organic silica microspheres is shown in FIG. 2, and it can be seen that the obtained organic silica microspheres are C-SiO₂The surface of the material is rough and round, and the diameter of the material is about 200 nm.

Example 2

A preparation method of an organic silicon dioxide loaded PMoW polyacid photocatalytic material comprises the following specific steps:

step 1) preparation of silica microspheres: tetraethoxysilane (CTAB, 0.3 g) and cetyltrimethylammonium bromide (TEOS, 1 mL) were dissolved in an aqueous solution of ethanol (ethanol 103.8mL, distilled water 82.8 mL)), ammonia was added dropwise to adjust pH =8, stirring was performed at 50 ℃ for 48 hours, the mixture was cooled to room temperature, the slurry was centrifuged, and washed with distilled water 3 times; after the obtained product is frozen and dried, the product is placed in a quartz crucible and calcined for 6 hours under 773K to prepare the silicon dioxide microspheres.

Step 2) organizing the silica microspheres: ultrasonically dispersing the silicon dioxide microspheres prepared in the step 1) in an N, N-dimethylformamide solution, adding a certain amount of silane coupling agent KH-560, adding 1mol/L sodium hydroxide solution to adjust the pH to be =9, stirring at room temperature for 2 hours, transferring the obtained slurry into a polytetrafluoroethylene reaction kettle, and reacting at 80 ℃ for 12 hours. Centrifugally separating the slurry, washing with distilled water at 80 ℃ for three times, freezing and drying to obtain the product, namely the organic silicon dioxide microsphere C-SiO₂。

Step 3) preparing the organic silicon dioxide loaded PMoW polyacid photocatalytic material: taking the organic silicon dioxide microspheres C-SiO prepared in the step 2)₂2g, ultrasonically dispersed in 62.5mL of deionized water, disodium hydrogen phosphate (2.15 g, 6 mmol) was dissolved in the solution in 12.5 mL of deionized water, while sodium molybdate (8.71 g, 36 mmol) was added and dissolved in 25mL of deionized water, and the three solutions were mixed and stirred at 90 ℃ for 30 minutes. To the mixture was added sodium tungstate solution (11.88 g), concentrated H was added dropwise₂SO₄To adjust pH =1.5, the resulting slurry was stirred for 8 hours at 90 ℃. And (3) freeze-drying, washing the obtained solid with an ethanol solution at 60 ℃ for 3 times, and heating at 300 ℃ for 4 hours to obtain the product, namely the silica-supported PMoW polyacid composite.

The XRD pattern of the organic silica supported PMoW polyacid photocatalytic material prepared in this example is shown in fig. 1, the crystallinity of PMoW polyacid is good, no peak of silica-related species is seen in the pattern, and PMoW polyacid is supported on the surface of silica microsphere.

The SEM image of the organic silica-supported PMoW polyacid composite material prepared in this example is shown in FIG. 3, which shows that the prepared material is a fibrous porous network structure with a porous sea urchin-like structure, and the diameter is within 500 nm.

Example 3

The silica-supported PMoW polyacid composite prepared in example 2 was applied as a photocatalyst to a photocatalytic sewage treatment device (laboratory simulated sewage), and the degradation efficiency of the composite on typical highly toxic hardly degradable pollutants in actual industrial wastewater was examined by using common hardly degradable erythromycin and highly toxic algal toxins as degradation objects. As shown in fig. 4, a degradation rate graph of the silica-supported PMoW polyacid photocatalytic material prepared in example 2 for degrading erythromycin and algal toxins is shown, and as can be seen from fig. 4, the removal rate of the organic silica-supported PMoW polyacid photocatalytic material prepared in example 2 for 50min is higher than 90% for erythromycin, and the removal rate of the algal toxins for 60min is higher than 90%, and the organic silica-supported PMoW polyacid composite material prepared in example 2 has an obvious effect of degrading erythromycin and algal toxins through photocatalysis.