CN116903252A - Green and environment-friendly preparation method of porous material, product obtained by method and application of product - Google Patents

Abstract

The invention discloses a green and environmentally friendly preparation method of porous materials and the resulting products and applications. In this method, solid powder and liquid phosphoric acid solution are batched, and then undergo high-temperature melting-water quenching-heat treatment to form phosphate glass-ceramic particles, and then further Treatment in phosphoric acid solution yields porous materials. In the present invention, phosphoric acid is used to treat phosphate glass-ceramics, and porous materials are formed by selective acid etching. The phosphoric acid waste liquid after acid treatment can be recycled as glass raw material, which greatly reduces production costs, avoids environmental pollution, and creates conditions for large-scale industrial production of porous materials. It is a green and environmentally friendly synthesis method. In addition, the synthesized porous material has two photocatalytic functional crystal phases and does not contain an obvious crystalline phase that is easily decomposed. It has high thermal stability and can be widely used in adsorption, catalytic degradation of organic pollutants, sewage treatment, photothermal Catalysis, high temperature catalysis and other fields.

Description

A green and environmentally friendly preparation method of porous materials and the resulting products and applications

Technical field

The invention relates to a green and environmentally friendly preparation method of porous materials and the resulting products. It also relates to the application of the porous materials in the fields of adsorption and photocatalysis, and belongs to the technical field of porous material preparation.

Background technique

Due to their large specific surface area, adsorption capacity and many special properties, porous materials are widely used in the fields of adsorption, separation, _CO2 reduction, photothermal catalysis, medium and high temperature desulfurization and denitrification catalyst carriers and other fields. There are many synthesis methods for porous materials, including sol-gel method, hydrothermal synthesis method, precipitation method and chemical etching method. Among them, the sol-gel method, hydrothermal synthesis method, and precipitation method are all based on chemical reactions in solution. They are collectively called wet chemical methods. They are a bottom-up synthesis path with low productivity and relatively high production costs. High, large-scale industrial production is difficult. The chemical corrosion law is a top-down model. Usually, a certain bulk non-porous material is first obtained, and then some substances are selectively dissolved through acid chemical corrosion to form a porous skeleton material. The advantage of this method is that industrial large-scale production can be used to prepare bulk non-porous materials in large quantities first, and then the porous materials can be obtained through acid etching. However, the disadvantage of this method is that some substances will be dissolved during the acid etching process, resulting in a waste of materials. At the same time, acid corrosion will produce a large amount of acidic waste liquid, and subsequent recycling and treatment will incur high costs, increase production costs, and cause environmental pollution.

In the production technology of porous glass or porous glass-ceramics, the commonly used corrosive medium is acidic solution (such as hydrochloric acid, sulfuric acid, etc.). Since the glass itself is acid-resistant and not alkali-resistant, using acid as the corrosive liquid can leave the glass skeleton and be selective. Etching away some components and structures in the glass to form porous structures and materials. However, hydrochloric acid and sulfuric acid solutions are highly corrosive and volatile, which will damage the health of production personnel. At the same time, the acid itself and the waste liquid generated during the production process will also cause serious pollution and harm to the environment. Therefore, the environmental safety of porous materials prepared by acid etching and the recycling of acidic waste liquid have become restrictive problems in the preparation of porous materials by chemical etching. Finding safe and alternative acid etching methods has become an urgent need.

In addition, porous materials have a porous skeleton structure, which has poor high-temperature stability and may collapse during high-temperature use. This phenomenon becomes more prominent, especially when the porous skeleton itself contains crystal water or easily decomposable substances. Once the porous structure collapses, the pores will disappear partially or completely, hindering the entry and exit of substances, and the surface area will decrease sharply. Therefore, its application in the fields of adsorption, separation, catalysis, etc. is limited. In severe cases, it will be unusable and the functions and functions of the porous material will be completely lost. Advantage. This problem is particularly prominent in copper-titanium phosphate glass-ceramic systems with high _TiO content. Previous research has shown that (A glass-ceramic approach to prepare porous TiO ₂ with self-supported nano-flakes: Thephase evolution and the thermal stability of the product), the porous material obtained after treatment with hydrochloric acid contains Ti(HPO ₄ ) _{2⋅2H 2} O crystal phase, when it is calcined at high temperature, all the nanosheets that constitute the porous structure of the material collapse, all the pores disappear, the porous structure no longer exists, and the advantage of being used under high temperature conditions is lost.

Contents of the invention

In view of the shortcomings in the preparation and high-temperature stability of the existing porous materials, the present invention provides a green and environmentally friendly preparation method of porous materials. The preparation method uses phosphoric acid solution as the raw material of phosphate glass-ceramics, and uses phosphoric acid as the raw material. The acidic solution for acid treatment avoids the use of highly corrosive and volatile HCl and H ₂ SO ₄ solutions, improving the safety of use. The acid treatment uses the same source as the glass synthetic raw material and has the same characteristics as the matrix system to be acid-etched. Phosphoric acid is used as a corrosive liquid, and the waste liquid generated after acid treatment can be reused as raw material, creating conditions for the reuse of waste liquid and realizing the green and environmentally friendly preparation of porous materials. At the same time, the porous material obtained by the phosphoric acid treatment of the present invention has strong high-temperature stability. After being calcined at a high temperature of 750°C, it still maintains the original porous structure without pore collapse or disappearance, and is more suitable for use under high temperature conditions.

The specific technical solutions of the present invention are as follows:

A green and environmentally friendly preparation method of porous materials, which method includes the following steps:

(1) According to the glass formula composition of MgO-CuO-TiO ₂ -P ₂ O ₅ , weigh each raw material and mix each raw material evenly to obtain a glass batch;

(2) Melt the glass batch material at high temperature to obtain a glass melt, then quench and dry the glass melt to obtain the parent glass;

(3) The parent glass is sequentially raised to its glass transition temperature and near the first glass crystallization peak temperature for heat treatment to obtain heat-treated glass;

(4) Put the heat-treated glass into a phosphoric acid solution for acid treatment. After acid treatment, wash with water and dry to obtain a porous material.

Further, in step (1), MgO is introduced from magnesium oxide, CuO is introduced from copper oxide, TiO ₂ is introduced from titanium dioxide, and P ₂ O ₅ is introduced from phosphoric acid solution. There is no special requirement for the concentration of the phosphoric acid solution, as long as the required amount of P ₂ O ₅ can be introduced.

Further, in step (1), in the glass formula, the molar content of MgO is 15~25%, the molar content of CuO is 20~30%, and the molar content of _TiO2 is 30~38%. The molar content of P ₂ O ₅ is 20~30%, and the sum of the molar contents of these four is 100%. Preferably, the molar content of MgO is 20%, the molar content of CuO is 24%, the molar content of TiO ₂ is 32%, and the molar content of P ₂ O ₅ is 24%.

Further, in step (1), the mixing sequence of the raw materials is: first mix the magnesium oxide, copper oxide, and titanium dioxide powder evenly, then slowly add the phosphoric acid solution and mix it into a slurry. If the mixture cannot become a slurry, then add Water makes the mixture into a slurry; after mixing evenly, the mixture is treated at 150~250°C until the water evaporates to dryness, then crushed and thoroughly mixed to obtain a glass batch. Heat treatment for 20 to 30 hours, then crush and mix thoroughly to obtain glass batch. The purpose of heating the mixture at 150~250℃ is to evaporate the water in the batch to form agglomerated mud, and then grind the agglomerated mud to obtain a uniformly mixed powder batch. At the same time, mixing the raw materials evenly before heating will only evaporate the water and ensure that the composition of the glass remains unchanged. The heating temperature can be 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 21°C, 220°C, 230°C, 240°C, or 250°C, and is preferably 200°C. Heat treatment until the mixture becomes agglomerated mud. The time will vary depending on the amount of water. In a specific embodiment of the present invention, the processing time is generally 20 to 30 hours, such as 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, 30 hours.

Further, in step (2), the step of high-temperature melting of the glass batch material is: raising the glass batch material from room temperature to 1200~1500°C at a heating rate of 3~8°C/min, and then maintaining the temperature at 1200~1500°C for 1 ~2 hours, the batch materials are completely melted, and the glass melt is obtained. Preferably, the glass batch is heated to 1350°C at a heating rate of 5°C/min and kept warm for 1 hour.

Further, in step (2), water quenching means pouring the obtained glass melt into water to form a glass state. Collect the water-quenched glass frit and dry it to become the parent glass.

Further, in step (3), the parent glass after water quenching and drying is subjected to DTA testing, and a DTA curve can be obtained. The glass transition temperature and the first crystallization peak temperature of glass can be obtained from the DTA curve (the glass transition temperature and the first crystallization peak temperature of glass are the two peaks in the DTA curve). The parent glass is first heated to the glass transition temperature and heat treated for 1 to 2 hours, and then heated to near the first crystallization peak temperature of the glass for 2 to 3 hours, and then cooled in the furnace to obtain heat-treated glass, which is phosphate microcrystalline Glass. If the temperature of the first crystallization peak of glass is T°C, then the temperature near the first crystallization peak temperature of glass is in the temperature range of T°C to (T+20)°C.

Further, in step (3), the parent glass is preferably heated to its glass transition temperature at a heating rate of 4~5°C/min for heat treatment, and then continues to be heat treated at a heating rate near the first crystallization peak temperature of the glass.

Further, in step (4), the concentration of the phosphoric acid solution is 2~5 mol/L, such as 2 mol/L, 3 mol/L, 4 mol/L, 5 mol/L, preferably 3 mol/L.

Further, in step (4), the volume ratio of the mass of the heat-treated glass to the phosphoric acid solution is 1g:50ml~1g:200ml, such as 1g:50ml, 1g:60ml, 1g:70ml, 1g:80ml, 1g:90ml, 1g : 100ml, 1g: 110ml, 1g: 120ml, 1g: 130ml, 1g: 140ml, 1g: 150ml, 1g: 160ml, 1g: 170ml, 1g: 180ml, 1g: 190ml, 1g: 200ml, preferably 1g: 100ml.

Further, in step (4), during acid treatment, the mixture of heat-treated glass and phosphoric acid solution is acid-treated in a sealed container to prevent the phosphoric acid solution from volatilizing and to provide certain pressure conditions for the acid treatment. For example, the mixture can be put into a container with a lid for acid treatment, or the mixture can be put into an open container such as a beaker, and then the mouth of the container can be sealed with a material such as polyethylene film. Preferably, the mixture is acid-treated in a beaker, and the beaker is sealed with 3 to 5 layers of polyethylene film.

Further, in step (4), the acid treatment temperature is 50 to 100°C, such as 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, preferably 100°C. The time required for phosphoric acid treatment is longer than that of hydrochloric acid and sulfuric acid, mostly 24-96h, such as 24h, 30h, 36h, 40h, 48h, 55h, 60h, 70h, 80h, 90h, 96h, preferably 48h.

Further, in step (4), after the acid treatment is completed, the glass sample and the phosphoric acid waste liquid are separated, and the acid-treated glass sample is washed and dried to obtain the final porous material. The water washing operation is as follows: add the acid-treated glass sample to an equal volume of water as the phosphoric acid solution, soak the glass sample for 2 to 3 hours, and then rinse the glass sample with water 3 to 5 times.

Furthermore, in step (4), the phosphoric acid waste liquid contains a large amount of phosphoric acid and also contains some Mg ²⁺ , Cu ²⁺ and Ti ⁴⁺ ions, which are all constituent elements of glass, so the phosphoric acid waste liquid can be directly used as The glass raw material is reused in step (1), and the phosphoric acid waste liquid can be used as the only raw material of P ₂ O ₅ , or the phosphoric acid waste liquid and the pure phosphoric acid solution can be used as the raw materials of P ₂ O ₅ . This can realize the recycling of waste acid solution, avoid the discharge of waste acid, solve the problems of environmental pollution and post-processing of waste acid, and make it more green and environmentally friendly. When reusing the phosphoric acid waste liquid, you can first detect the P ⁵⁺ , Mg ²⁺ , Cu ²⁺ and Ti ⁴⁺ contents, and then reuse the phosphoric acid waste liquid as a raw material for P ₂ O ₅ and calculate the waste liquid at the same time The amount of Mg, Cu, and Ti introduced is calculated according to the glass formula, and the amount of pure phosphoric acid solution, magnesium oxide, copper oxide, and titanium dioxide required in addition to the waste liquid is calculated. The missing parts are then supplemented by these pure raw materials. There are no special requirements for the concentration of phosphoric acid waste liquid.

The preparation method of the present invention uses phosphoric acid as the glass raw material and at the same time as the acid solution for hyaluronic acid treatment. The phosphoric acid waste liquid after the acid treatment can be reused as the glass raw material, which greatly improves the safety and green environmental protection of the preparation, and also reduces the cost. Preparation costs. At the same time, SEM analysis shows that the porous material obtained by the phosphoric acid treatment of the present invention is a porous skeleton composed of nanosheets (see Figure 3). XRD analysis shows that this porous material simultaneously contains two crystal phases with photocatalytic functions - MgTi ₄ (PO ₄ ) ₆ and anatase TiO ₂ phases (see Figure 2), and does not contain significant thermal decomposition , Ti(HPO ₄ ) _2• 2H ₂ O crystal phase with collapsed pore structure, the pore structure does not collapse after calcination at 750℃ (see Figure 4), so this porous material has strong high temperature stability and excellent high temperature resistance, and can be used in high temperature environments It has better advantages when used below.

Furthermore, the porous material of the present invention can be used as an adsorbent, a photocatalyst, etc., so the application of the porous material as an adsorbent or a photocatalyst is also within the scope of the present invention.

Furthermore, the porous material of the present invention has good stability at high temperatures, at least at a high temperature of 750°C. Therefore, the present invention also provides the application of the porous material as a photothermal catalyst or a high-temperature catalyst carrier.

Compared with existing materials and technologies, the beneficial effects of the present invention are:

1. In the preparation method of porous materials provided by the present invention, a phosphoric acid solution with low volatility, low corrosiveness, low environmental toxicity, and homologous to synthetic materials is used as a raw material, and the phosphoric acid solution is used to treat the phosphate glass-ceramic matrix. Corrosion is carried out to form porous materials, and the resulting phosphoric acid waste liquid can be reused as raw material, realizing the recovery and production reuse of production waste liquid.

2. The preparation process of the present invention is easy to be industrialized, the production process is easy to control, and is suitable for industrial preparation of porous materials. In addition, the preparation process realizes the recycling of materials, greatly reduces production costs, avoids environmental pollution, is green and environmentally friendly, and conforms to the concept of sustainable development. It is of great significance for the large-scale industrial promotion and commercial application of porous materials.

3. The present invention uses phosphoric acid solution as the acid treatment etching liquid, which changes the leaching of various elements in the phosphate glass-ceramics and also changes the kinetics of in-situ crystal phase generation. The result is that the Ti with crystal water is significantly suppressed ( The formation of HPO ₄ ) _2• 2H ₂ O crystal phase improves the high-temperature stability of the generated porous material skeleton, making it more advantageous for use in high-temperature environments.

4. The porous material obtained by the method of the present invention has two composite photocatalytic functional crystal phases and good adsorption and degradation performance, and can be widely used in adsorption, catalytic degradation of organic pollutants, sewage treatment, photothermal catalysis, high temperature catalysis and other fields.

Description of the drawings

Figure 1 shows the DTA curve of the parent glass.

Figure 2 shows the XRD pattern of porous materials.

Figure 3 is a scanning electron microscope picture of porous materials.

Figure 4 is a scanning electron microscope picture of porous materials after high-temperature calcination.

Figure 5 shows the _N2 isotherm adsorption curve of porous materials.

Figure 6 shows the concentrations of Mg, Cu, Ti and P ions in the recovered phosphoric acid solution after acid treatment.

Detailed ways

In order to make the material and technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

If the specific experimental conditions are not specified in the examples, conventional conditions are usually followed, or conditions recommended by the reagent company; the reagents, consumables, etc. used in the following examples can all be obtained through commercial channels unless otherwise specified.

The experimental results of the present invention are obtained by the following method: using a comprehensive thermal analyzer to perform differential thermal analysis (DTA) on the glass. Use an X-ray diffractometer to obtain the diffraction pattern of the sample and conduct phase analysis. Scanning electron microscopy was used to obtain the surface micromorphology of the sample. Use a nitrogen isothermal adsorption instrument to measure the N ₂ isothermal adsorption curve of the sample, calculate the specific surface area according to the BET model, obtain the pore size distribution curve according to the BJH model, and determine the pore size from the peak point data of the curve. The pore volume is determined by the adsorption at the maximum relative pressure of the N ₂ adsorption curve. Quantity determined.

Example 1

A method for preparing porous materials, including the following steps:

1. Preparation of parent glass

According to the glass formula composition of MgO-CuO-TiO ₂ -P ₂ O ₅ , light magnesium oxide, copper oxide, titanium dioxide, and 85wt% phosphoric acid solution are selected as raw materials. According to MgO: CuO: TiO ₂ : P ₂ O ₅ = 20 : 24:32:24 molar ratio. Accurately weigh each raw material. First, preliminarily mix magnesium oxide, copper oxide and titanium dioxide, then slowly add 85wt% phosphoric acid solution, and add an appropriate amount of distilled water to mix evenly to make it appear as a mud. State; after mixing evenly, the mixture is heated at 200°C for 24 hours. The water in the mixture is evaporated into agglomerated mud, and then the mud is crushed and fully mixed to obtain a glass batch. Put the glass batch material into an alumina crucible, and perform high-temperature melting of the glass batch material in the Nobadi high-temperature lifting furnace. The melting process is: raising the temperature from room temperature to 1350°C at a heating rate of 5°C/min. , and then kept at 1350°C for 1 hour to completely melt the batch materials and obtain a glass melt. After the high-temperature melting is completed, the glass melt is quickly poured into water for water quenching. Collect the water-quenched glass frit and dry it. This sample is the parent glass.

2. Preparation of heat-treated glass

Use the HCT-4 comprehensive thermal analyzer to conduct DTA testing on the parent glass, and obtain the DTA curve of the parent glass (see Figure 1). Then heat a certain amount of the parent glass in step 1 to its glass transition temperature (622°C) at a heating rate of 5°C/min for 1 hour, and then continue to heat it at a heating rate of 5°C/min until the first crystallization of the glass. Heat treatment at the peak temperature (716°C) for 2 hours, and then cool with the furnace to obtain heat-treated glass.

3. Preparation of porous materials

Add a certain amount of the heat-treated glass in step 2 and 3mol/L phosphoric acid solution into the beaker at the ratio of 1g:100ml, seal the mouth of the beaker with three layers of polyethylene film, and then put the beaker into a drying oven at 100°C Acid treatment for 48h. After the acid treatment, pour out the phosphoric acid solution and recover it, then soak the glass sample with an equal volume of distilled water as the phosphoric acid solution for 2 hours, then rinse the glass sample with distilled water three times, and dry it to obtain a porous material sample.

XRD analysis of the obtained porous material showed that the crystal phase of the porous material is mainly MgTi ₄ (PO ₄ ) ₆ and also contains anatase TiO ₂ crystal phase (see Figure 2). The SEM image of the sample is shown in Figure 3. It can be seen that a large number of nanosheets grow on the surface of the sample, and the nanosheets are connected to each other to form a porous structure. The N ₂ adsorption isotherm curve of this sample shows an obvious type IV adsorption isotherm with an H3 type hysteresis loop, indicating that the sample has a mesoporous structure and the pore diameter is mostly distributed between 2-20nm (see Figure 5). The surface area of the sample and The pore volumes reached 16.77m ² /g and ^{0.074cm 3} /g respectively.

Example 2

A method for preparing porous materials, including the following steps:

1. Preparation of parent glass

An inductively coupled plasma spectrometer (Agilent ICPOES730) was used to measure the concentrations of Mg, Cu, Ti and P ions in the acid-treated phosphoric acid solution recovered in Example 1 (see Figure 6). The recovered acid-treated phosphoric acid solution is used as the raw material of P ₂ O ₅ , and P ₂ O ₅ is completely introduced from the recovered phosphoric acid solution. According to the glass formula composition of MgO-CuO-TiO ₂ -P ₂ O ₅ , calculate the required amount of P ₂ O ₅ according to the molar ratio of MgO: CuO: TiO ₂ : P ₂ O ₅ = 20:24:32:24, Based on the calculation results, the contents of Mg, Cu, and Ti introduced together in the acid-treated phosphoric acid solution are also calculated. Finally, the remaining required amounts of MgO, CuO, and _TiO are calculated and introduced using magnesium oxide, copper oxide, and titanium dioxide.

Accurately weigh the calculated masses of magnesium oxide, copper oxide and titanium dioxide, and mix them initially, then slowly add the recovered acid-treated phosphoric acid solution, and add an appropriate amount of distilled water and mix evenly to make it appear in a slurry state; After mixing evenly, the mixture is heated at 200°C for 24 hours. The mixture is evaporated to dryness and becomes agglomerated mud. The mud is then crushed and thoroughly mixed to obtain a glass batch. Put the glass batch material into an alumina crucible, and perform high-temperature melting of the glass batch material in the Nobadi high-temperature lifting furnace. The melting process is: raising the temperature from room temperature to 1350°C at a heating rate of 5°C/min. , and then kept at 1350°C for 1 hour to completely melt the batch materials and obtain a glass melt. After the high-temperature melting is completed, the glass melt is quickly poured into water for water quenching. Collect the water-quenched glass frit and dry it. This sample is the parent glass.

2. Preparation of heat-treated glass

Use the HCT-4 comprehensive thermal analyzer to conduct DTA testing on the parent glass, and obtain the DTA curve of the parent glass (see Figure 1). Then heat a certain amount of the parent glass in step 1 to its glass transition temperature (610°C) at a temperature rise rate of 5°C/min for 1 hour, and then continue to heat it up to the first crystallization of the glass at a temperature rise rate of 5°C/min. Heat treatment at the peak temperature (698°C) for 2 hours, and then cool with the furnace to obtain heat-treated glass.

3. Preparation of porous materials

Add a certain amount of the heat-treated glass in step 2 and 3mol/L phosphoric acid solution into the beaker at the ratio of 1g:100ml, seal the mouth of the beaker with three layers of polyethylene film, and then put the beaker into a drying oven at 100°C Acid treatment for 48h. After the acid treatment, pour out the phosphoric acid solution and recover it, then soak the glass sample with an equal volume of distilled water as the phosphoric acid solution for 2 hours, then rinse the glass sample with distilled water three times, and dry it to obtain a porous material sample.

XRD analysis of the obtained porous material showed that the crystal phase of the porous material is also dominated by MgTi ₄ (PO ₄ ) ₆ and contains anatase TiO ₂ crystal phase (see Figure 2). The SEM image of the sample is shown in Figure 3. It can be seen that a large number of nanosheets are also grown on the surface of the sample. The nanosheets are connected to each other to form a porous structure. The nanosheets are thinner than the nanosheets of the sample in Example 1. The N ₂ adsorption isotherm curve of this sample shows an obvious type IV adsorption isotherm with an H3 type hysteresis loop, indicating that the sample also has a mesoporous structure, with pore diameters mostly distributed between 2-30nm (see Figure 5), and the sample surface area The surface area and pore volume of this sample reached 34.18m ² /g and 0.099cm ³ /g respectively. The surface area and pore volume of this sample are both higher than the surface area (16.77 m ^2. g ^-1 ) and pore volume of the sample obtained when phosphoric acid was directly batched in Example 1. (0.074 cm ^3. g ^-1 ) increases, which facilitates the adsorption of dyes and facilitates subsequent photocatalysis.

The obtained porous material was calcined at a high temperature of 750°C for 0.5 h. The SEM image is shown in Figure 4. It can be seen that the calcined sample still maintains the original porous structure, and the surface of the nanosheets becomes rough, and new particles appear on some nanosheets. of holes.

The recovered acid-treated phosphoric acid solution is used to synthesize the glass melt again, which greatly reduces the high cost of recycling the acidic waste liquid and realizes the recycling of materials; at the same time, the functional crystal phase of the obtained material is consistent with the embodiment 1, but its nanosheets are more numerous, thinner, and have a larger surface area, which is undoubtedly beneficial for improving material performance.

Comparative ratio

Obtain heat-treated glass according to the method of Example 1. Add the heat-treated glass and 3 mol/L hydrochloric acid solution into a beaker at a ratio of 1g:100ml. Use a three-layer polyethylene film to seal the mouth of the beaker, and then place the beaker into a 100°C oven. Acid treatment in dry box for 13h and 48h respectively. After the acid treatment, pour out the hydrochloric acid solution, soak the glass sample with an equal volume of distilled water as the hydrochloric acid solution for 2 hours, rinse the glass sample with distilled water three times, and dry it to obtain a porous material sample. The sample treated with acid for 13 hours is Comparative Example 1, and the sample treated with acid for 48 hours is Comparative Example 2.

XRD analysis of the obtained porous materials showed that the samples of Comparative Examples 1 and 2 only contained one photocatalytic functional crystal phase, namely anatase TiO ₂ as the main crystal phase, and also contained Ti(HPO ₄ ) _2• 2H ₂ O crystal phase (see Figure 2). The SEM image of the sample is shown in Figure 3. It can be seen that a large number of nanosheets grow on the surface of the sample, and the nanosheets are connected to each other to form a porous structure.

The porous material of Comparative Example 1 was calcined at a high temperature of 750°C for 0.5 h, and then the calcined sample was subjected to SEM analysis. The results are shown in Figure 4. It can be seen from the figure that after calcining, due to Ti(HPO ₄ ) With the decomposition of _{the 2•} 2H ₂ O crystal phase, the nanosheets constituting the porous structure completely collapse and the pores disappear. The disappearance of pore channels will cause the specific surface area and pore volume of porous materials to be greatly reduced, affecting its application.

Application examples

In order to verify the performance of the porous material prepared by the present invention, the samples prepared in Example 2 and Comparative Example 2 are selected below to conduct experiments on adsorption and photocatalytic degradation of organic dye methylene blue solution. A spectrophotometer was used to measure the absorbance of the methylene blue solution before and after the porous material adsorbed and photocatalytically degraded the methylene blue solution at a wavelength of 665 nm, and the concentration of methylene blue in the solution was calculated based on the standard curve. The experimental process is as follows:

Take 50 mg of the products prepared in Example 2 and Comparative Example 2 (ground through a standard sieve of 50 to 140 mesh), and place them in 50 mL of a methylene blue solution with a concentration of 10 mg/L. Stir and adsorb under dark conditions until the sample reaches adsorption equilibrium. After the sample reaches adsorption equilibrium, turn on the UV lamp (300W) for irradiation and continue magnetic stirring, so that the sample can degrade the methylene blue molecules in the solution under light conditions. The adsorption efficiency of the sample to methylene blue in the methylene blue solution, according to the formula calculate. In the formula, A _t is the adsorption efficiency at time t, C ₀ is the concentration of the original solution, and C _t is the concentration of the solution at time t.

The results show that after stirring for 1.5 hours under dark conditions, the products of Example 2 and Comparative Example 2 both reached adsorption equilibrium for the methylene blue solution, and the adsorption rates were 52.04% and 47.2% respectively. The adsorption effect of the Example 2 sample was better than that of the Comparative Example. 2. After stirring under UV lamp irradiation for 6.5 hours, the methylene blue solutions in the products of Example 2 and Comparative Example 2 were both close to clear solutions. The total degradation rates of methylene blue dye molecules in the products of Example 2 and Comparative Example 2 were similar, which were 95.43% and 95.43% respectively. 95.87%.

The above descriptions are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included in the protection scope of this application.

Claims (10)

1. A green and environmentally friendly preparation method of porous materials, which is characterized by comprising the following steps: (1) According to the glass composition of MgO-CuO-TiO ₂ -P ₂ O ₅ , weigh each raw material and mix each raw material evenly to obtain a glass batch; (2) Melt the glass batch material at high temperature to obtain a glass melt, then quench and dry the glass melt to obtain the parent glass; (3) Heat-treat the parent glass sequentially to its glass transition temperature and near the first crystallization peak temperature of the glass to obtain heat-treated glass; (4) Put the heat-treated glass into a phosphoric acid solution for acid treatment. After acid treatment, wash with water and dry to obtain a porous material. 2. The green and environmentally friendly preparation method according to claim 1, characterized in that: in step (4), the concentration of the phosphoric acid solution is 2~5 mol/L; preferably, in step (4), the quality of the heat-treated glass is equal to that of the phosphoric acid. The volume ratio of the solution is 1g:50ml~1g:200ml. 3. The green and environmentally friendly preparation method according to claim 1, characterized in that: in step (4), the mixture of heat-treated glass and phosphoric acid solution is acid-treated in a closed container; preferably, the acid treatment temperature is 50~ 100℃, treatment time is 24-96h. 4. The green and environmentally friendly preparation method according to claim 1, characterized in that: in step (4), the water washing operation is: adding the acid-treated glass sample into water of the same volume as the phosphoric acid solution, and soaking the glass sample for 2~ 3 hours, then rinse the glass sample with water 3-5 times. 5. The green and environmentally friendly preparation method according to claim 1, characterized in that: in step (1), MgO, CuO, and TiO ₂ are introduced by their corresponding oxides, and P ₂ O ₅ is introduced by a phosphoric acid solution; preferably In step (1), in the glass formula, the molar content of MgO is 15~25%, the molar content of CuO is 20~30%, the molar content of _TiO2 is 30~38%, P The molar content of ₂ O ₅ is 20~30%, and the sum of the molar contents of these four is 100%. 6. The green and environmentally friendly preparation method according to claim 1 or 5, characterized in that: in step (4), after the acid treatment, the acid-treated glass sample and the phosphoric acid waste liquid are separated, and the phosphoric acid waste liquid is reused in step (4). 1), as a raw material for glass. 7. The green and environmentally friendly preparation method according to claim 5, characterized in that: in step (1), the mixing sequence of the raw materials is: first, mix the magnesium oxide, copper oxide, and titanium dioxide powder evenly, and then slowly add the phosphoric acid solution to mix. into a slurry. If the mixture cannot become into a slurry, add water to make the mixture into a slurry; after mixing evenly, process the mixture at 150~250℃ until the water evaporates to dryness, then crush and mix thoroughly to obtain a glass compound material. 8. The green and environmentally friendly preparation method according to claim 1, characterized in that: in step (2), the step of high-temperature melting of the glass batch is: the glass batch is heated from room temperature at a heating rate of 3 to 8°C/min. Rise to 1200~1500℃, and then keep it at 1200~1500℃ for 1~2 hours, so that the batch materials are completely melted and the glass melt is obtained. 9. The green and environmentally friendly preparation method according to claim 1, characterized in that: in step (3), the parent glass after water quenching and drying is heat-treated to its glass transition temperature at a heating rate of 4~5°C/min for 1~ 2 hours, and then continue to heat up to a temperature near the first crystallization peak temperature of the glass for 2 to 3 hours, and then cool with the furnace to obtain heat-treated glass; where the temperature near the first crystallization peak temperature of the glass is the first crystallization peak temperature of the glass Or a temperature 20°C or less higher than the first crystallization peak of glass. 10. Porous materials prepared according to the green and environmentally friendly preparation method of porous materials according to any one of claims 1 to 9, and the use of the porous materials as adsorbents, photocatalysts, photothermal catalysts or high-temperature catalyst carriers.