Preparation method of photocatalytically active hydrophilic sponge

Abstract

The application discloses a preparation method of a photocatalytic active hydrophilic sponge, which comprises two steps of preparing a titanium-cobalt composite oxide photocatalyst powder and preparing a photocatalytic active hydrophilic sponge. The produced hydrophilic sponge has a large pore network structure and fast water absorption, and has excellent photocatalytic activity under visible light, and is an optimal material for water purification treatment. The photocatalytic active hydrophilic sponge prepared by the application is closely combined between a network structure and a photocatalytic active center, and does not have problems such as easy falling off of catalytic components and uneven distribution. The photocatalyst used is a titanium-cobalt composite oxide, which is a composite semiconductor material, has a band gap of about 2.25 eV, and has an absorption light wavelength of about 550 nm, can well respond to visible light, and has good photocatalytic activity.

Description

TECHNICAL FIELD

[0001] The application relates to the field of water purification materials, in particular to a preparation method of a photocatalytically active hydrophilic sponge. BACKGROUND

[0002] The applicant discloses a one-step method for preparing a hydrophilic sponge for water treatment in CN111040113A. The hydrophilic sponge can sink into water and has good adsorption and bearing capacity, and is commonly used for adsorption and collection of pollutants in the water treatment process. However, the hydrophilic sponge cannot directly degrade or convert pollutants, and further recovery treatment such as incineration is required after adsorbing pollutants, which limits the application range of the hydrophilic sponge. However, if photocatalytic materials are introduced into the production process of the hydrophilic sponge, an improved version of the hydrophilic sponge capable of photocatalytic decomposition of pollutants using natural light can undoubtedly expand the use range of the hydrophilic sponge.

[0003] Photocatalytic degradation has a broad spectrum of degradation capacity, and the degradation rate of organic pollutants can reach 90-99.9%, with less by-product and low energy consumption. Nano-TiO2 has good photocatalytic performance, good chemical stability, no toxicity and harm, and is widely used. The forbidden band width of anatase TiO2 is 3.2eV, and after absorbing ultraviolet light (wavelength <387nm), the energy level of electrons jumps, a hole-electron pair is generated, •OH is generated, and organic pollutants are catalytically degraded. CN101966469A and other patents disclose a method for loading a photocatalyst mainly composed of TiO2 on the surface of a network polyurethane sponge by impregnation to prepare a supported photocatalytic material. However, the photocatalytic sponge prepared by this method has a surface active component that is easy to fall off, poor mixing degree, and a complex preparation process, and the effect is not good if used for improvement of the hydrophilic sponge. In addition, nano-TiO2 has a defect, that is, an additional ultraviolet light source is required to meet the requirements of TiO2 photocatalytic reaction, so nano-TiO2 needs to be improved to realize red shift of light absorption and form photocatalytic effect by absorbing visible light. SUMMARY

[0004] The main purpose of the present application is to provide a preparation method of a photocatalytically active hydrophilic sponge, which uses a coprecipitation method to prepare a photocatalyst precursor as a powder raw material, synthesizes the photocatalyst precursor into a hydrophilic sponge structure in one step, and adds an opening agent to prepare a grid-shaped hydrophilic sponge with photocatalytic activity for photocatalytic treatment of wastewater.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows: a preparation method of a photocatalytically active hydrophilic sponge, comprising the following steps:

[0006] (1) Preparation of titanium cobalt composite oxide photocatalyst powder: titanium tetrachloride is dissolved in a mixed solvent of isopropyl alcohol and deionized water to obtain solution A; CoCl2·6H2O is dissolved in a mixed solvent of isopropyl alcohol and deionized water to obtain solution B; then under low speed stirring of 100-150 r / min, solution B is mixed uniformly with solution A. Maintain low speed stirring, and 10-15% ammonia water is added dropwise into the mixed solution until no precipitate is observed at the dropwise position, continue to stir for 5-6 minutes, stand, centrifugal filtration to obtain filter residue, wash the filter residue with 55-65% ethanol, compress to obtain solid filter residue cake, place the solid filter residue cake in a constant temperature oven, dry at 100-120°C for 3-5 hours, then calcine at 350-450°C for 4-6 hours, cool to room temperature, grind and sieve to obtain 300-400 mesh titanium cobalt composite oxide photocatalyst powder;

[0007] (2) Preparation of photocatalytically active hydrophilic sponge: the titanium cobalt composite oxide photocatalyst powder obtained in step (1) is mixed with polyether polyol to prepare a slurry, then under low speed stirring of 500-600 r / min, hydrophilic polyol, hydrophilic auxiliary agent, foam stabilizer, foaming agent, open cell agent and catalyst are sequentially added into the stirring barrel, then diisocyanate is quickly added, the stirring speed is increased to 4000-4500 r / min, and the slurry is stirred rapidly for 10-15 seconds, then the stirred sponge slurry is injected into a mold to form a sponge blank, and the sponge blank is cured at room temperature for 36-48 hours, and then cut into small pieces of photocatalytically active hydrophilic sponge.

[0008] Further, in step (1), in the solution A, the mass ratio of titanium tetrachloride, isopropyl alcohol and deionized water is 190: 50-80: 500; in the solution B, the mass ratio of CoCl2·6H2O, isopropyl alcohol and deionized water is 240: 50-80: 500.

[0009] Further, in step (1), solution B is mixed with solution A, and the molar ratio of titanium tetrachloride and CoCl2·6H2O in the obtained mixed solution is 1:1.5-1.5:1.

[0010] Further, in step (2), the mass fractions of each component are as follows: polyether polyol 40-60 parts, hydrophilic polyol 40-60 parts, hydrophilic auxiliary agent 10-15 parts, foam stabilizer 2-4 parts, composite photocatalyst precursor 15-25 parts, open cell agent 3-6 parts, foaming agent 2-4 parts, catalyst 1-2 parts, and diisocyanate 35-60 parts.

[0011] Further, in step (2), the hydrophilic polyether polyol is a polyether or polyester polyol with a ratio of monomer ethylene oxide (EO) to propylene oxide (PO) greater than 50% in synthesis, a functionality of 2-4, and an average molecular weight of 500-5000. Preferably, it is P-156 or LH-1623.

[0012] Further, in step (2), the polyether polyol is a common soft polyether, preferably PPG5616 or F-3156.

[0013] Further, in step (2), the hydrophilic auxiliary agent is a non-hydrolytic silicone oil with a polyether backbone and a silicon-based end cap, preferably HQ990.

[0014] Further, in step (2), the foam stabilizer is a combination of a hydrophilic silicone oil capped with silicone and a soft polyether with open pores, preferably one or two of 9205, HC8009, HC605, and L-580.

[0015] Further, in step (2), the foaming agent is deionized water.

[0016] Further, in step (2), the pore opener is a polyether polyol with an average molecular weight greater than 10000, preferably KXM-4.

[0017] Further, in step (2), the catalyst is composed of one or more of organotin catalysts, organobismuth catalysts, and amine catalysts. Preferably, the organotin catalyst is stannous octoate or dibutyltin dilaurate, the amine catalyst is triethylenediamine, bis(2-dimethylaminoethyl) ether, or a reactive amine catalyst derived from such amines, preferably triethylenediamine.

[0018] Further, in step (2), the diisocyanate is one or more of TD80I, modified MDI 8019, modified MDI 8223, and polymeric MDI PM200.

[0019] Further, the hydrophilic sponge preparation process in step (2) can also use horizontal foaming machines, vertical foaming machines, and other methods for foaming.

[0020] Further, in step (2), the hydrophilic sponge prepared has a pore size of 30-50 PPI, which can be adjusted by changing the amount of silicone oil and pore opener.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] One, the photocatalyst used in the present application is titanium cobalt composite oxide (main component is CoTiO3), which is a composite semiconductor material with a band gap of about 2.25eV and an absorption wavelength of about 550nm, and can respond to visible light well. Energy level transition can occur under visible light conditions to produce active groups, oxidize and degrade pollutants in water, and photocatalytic effect can be produced without absorbing ultraviolet light. Therefore, it has good photocatalytic activity under visible light.

[0023] Two, the present application prepares a hydrophilic sponge containing titanium cobalt composite oxide photocatalytic material. The sponge structure body serves as an adsorption and carrier material, has fast water absorption, can sink in water after saturated water absorption, does not float on the water surface, is beneficial to the continuous adsorption and catalytic degradation of impurities in water, and completely degrades into small molecular compounds such as carbon dioxide and water, thereby completely eliminating water pollution and being an optimal material for water treatment.

[0024] Three, in the present application, titanium cobalt composite oxide photocatalytic material is directly used as raw material and added to the foaming system, and the catalytic center is uniformly dispersed. The photocatalytic active center is closely combined on the sponge network structure, the structure is stable, the binding force is strong, and it will not be combined by adsorption like the supported photocatalyst prepared by the impregnation method. Therefore, the hydrophilic sponge with photocatalytic activity prepared by the present application does not have problems such as easy falling off of catalytic components and uneven activity of catalytic center.

[0025] Four, the photocatalytic active hydrophilic sponge prepared by the present application adjusts the pore size by adding an opening agent and changing the amount of silicone oil and opening agent, which is beneficial to improving the adsorption and desorption rate and speeding up the photocatalytic reaction, and is also beneficial to reducing the water flow resistance in the water treatment process without affecting the flow of water system. DETAILED DESCRIPTION

[0026] In order to make the technical means, purposes and effects achieved by the present application easy to understand, the present application will be further described below in combination with specific embodiments.

[0027] In the examples

[0028] Hydrophilic polyol: P-156 from Jiahua Chemical, LH-1623 from Jiangsu Lihong;

[0029] Polyether polyol: PPG5616 from China Shell, F-3156 from Wanhua Chemical;

[0030] Hydrophilic aid: HQ990 from Han Chuanxin Material;

[0031] Foam stabilizer: 9205 from Shoubobo Electronics, HC605 from Han Chuanxin Material;

[0032] Opening agent: KXM-4 from Huai'an Kaixin Company Example 1

[0033] Preparation of titanium cobalt composite oxide photocatalyst powder

[0034] In 250 grams of deionized water, 25 grams of isopropyl alcohol was added to make a mixed solvent, 94.5 grams of TiCl4(molar mass 189.7 grams / mole, about 0.50 moles) was added, and stirred to make solution A; in 375 grams of deionized water, 60 grams of isopropyl alcohol was added to make a mixed solvent, 179.1 grams of CoCl2•6H2O (molar mass 238.8 grams / mole, about 0.75 moles) was added, and stirred to make solution B; under low speed stirring at 100-150 r / min, solution B was mixed with solution A uniformly, the molar ratio of titanium tetrachloride and CoCl2•6H2O in the mixed solution was 1:1.5. Maintaining low speed stirring, 10% ammonia water was added dropwise to the mixed solution until no precipitate was observed at the dropping point, and continued to stir for 5 minutes, and then centrifuged after standing to obtain the filter residue, which was washed with 55% ethanol, and then compressed into a solid filter cake, which was placed in an oven and dried at 120°C for 4 hours, then placed in a muffle furnace and calcined at 450°C for 4 hours, cooled to room temperature, ground and sieved to obtain 82.5 grams of 400 mesh titanium cobalt composite oxide photocatalyst powder. Example 2

[0035] Preparation of titanium cobalt composite oxide photocatalyst powder

[0036] In 375 grams of deionized water, 60 grams of isopropyl alcohol was added to make a mixed solvent, 142.28 grams of TiCl4(molar mass 189.7 grams / mole, about 0.75 moles) was added, and stirred to make solution A; in 250 grams of deionized water, 25 grams of isopropyl alcohol was added to make a mixed solvent, 119.4 grams of CoCl2•6H2O (molar mass 238.8 grams / mole, about 0.5 moles) was added, and stirred to make solution B; under low speed stirring at 100-150 r / min, solution B was mixed with solution A uniformly, the molar ratio of titanium tetrachloride and CoCl2•6H2O in the mixed solution was 1.5:1. Maintaining low speed stirring, 15% ammonia water was added dropwise to the mixed solution until no precipitate was observed at the dropping point, and continued to stir for 5 minutes, and then centrifuged after standing to obtain the filter residue, which was washed with 65% ethanol, and then compressed into a solid filter cake, which was placed in an oven and dried at 120°C for 6 hours, then placed in a muffle furnace and calcined at 350°C for 6 hours, cooled to room temperature, ground and sieved to obtain 84.7 grams of 300 mesh titanium cobalt composite oxide photocatalyst powder. Example 3

[0037] Preparation of titanium cobalt composite oxide photocatalyst powder

[0038] In 300 g of deionized water, 40 g of isopropyl alcohol was added to make a mixed solvent, 113.8 g of TiCl4(molar mass 189.7 g / mol, about 0.6 mol) was added, and stirred to make solution A; in 250 g of deionized water, 30 g of isopropyl alcohol was added to make a mixed solvent, 119.4 g of CoCl2·6H2O (molar mass 238.8 g / mol, about 0.5 mol) was added, and stirred to make solution B; under low speed stirring at 100-150 r / min, solution B was mixed with solution A uniformly, and the molar ratio of titanium tetrachloride and CoCl2·6H2O in the mixed solution was 1.2:1. While maintaining low speed stirring, 13% ammonia water was added dropwise to the mixed solution until no precipitate was observed at the dropwise position, and continued to stir for 5 minutes, and after standing, centrifugal filtration was performed to obtain a filter residue, which was washed with 60% ethanol and compressed into a solid filter cake. The solid filter cake was placed in an incubator, dried at 120°C for 6 hours, then placed in a muffle furnace and calcined at 430°C for 5 hours, cooled to room temperature, ground and sieved to obtain 76.6 g of 350 mesh titanium-cobalt composite oxide photocatalyst powder.

[0039] The titanium-cobalt composite oxide photocatalyst powder prepared in Examples 1-3 was used to prepare photocatalytically active hydrophilic sponges in Examples 4-7. Example 4

[0040] Preparation of photocatalytically active hydrophilic sponges

[0041] 30 g of titanium-cobalt composite oxide photocatalyst powder prepared in Example 1 was mixed with 120 g of PPG5616 polyether polyol to make a slurry, then 80 g of P-156 hydrophilic polyol, 30 g of HQ990 hydrophilic auxiliary agent, 8 g of deionized water, 4 g of foam stabilizer (9205), 12 g of opening agent, 3 g of triethylene diamine catalyst, and 1 g of organic tin catalyst were sequentially added to the stirring tank under low speed stirring at 500-600 r / min, and then 70 g of diisocyanate (TDI80) was added quickly, the stirring speed was increased to 4000 r / min, and the slurry was stirred for 12 seconds. The sponge slurry was then poured into a mold to form a sponge blank, which was cured at room temperature for 36 h, and then cut into small pieces of photocatalytically active hydrophilic sponge material. The physical properties and photocatalytic performance of the product were detected by sampling. Example 5

[0042] Preparation of photocatalytically active hydrophilic sponges

[0043] The titanium cobalt composite oxide photocatalyst powder prepared in Example 2, 50 g, was mixed with PPG5616 polyether polyol, 80 g, to form a slurry, which was then stirred at a low speed of 500-600 r / min. Then, LH-1623 hydrophilic polyol, 120 g, HQ990 hydrophilic auxiliary agent, 20 g, deionized water, 4 g, foam stabilizer (HC605), 8 g, cell opener, 6 g, triethylene diamine catalyst, 1 g, and organic tin catalyst, 3 g, were sequentially added into the stirring barrel, and stirred uniformly. Then, diisocyanate (MDI8223), 120 g, was quickly added into the stirring barrel, and the stirring speed was increased to 4000 r / min for 10 seconds. The sponge slurry after stirring was injected into a mold to form a sponge blank, which was aged at room temperature for 48 h, and then cut into small pieces of photocatalytically active hydrophilic sponge material. The physical properties and photocatalytic performance of the product were detected. Example 6

[0044] Preparation of photocatalytically active hydrophilic sponge

[0045] The titanium cobalt composite oxide photocatalyst powder prepared in Example 3, 44 g, was mixed with PPG5616 polyether polyol, 95 g, to form a slurry, which was then stirred at a low speed of 500-600 r / min. Then, P-156 hydrophilic polyol, 105 g, HQ990 hydrophilic auxiliary agent, 30 g, deionized water, 5.6 g, foam stabilizer (9205), 5 g, cell opener, 8 g, triethylene diamine catalyst, 1.2 g, and organic tin catalyst, 1.4 g, were sequentially added into the stirring barrel, and stirred uniformly. Then, diisocyanate (MDI8223), 106 g, was quickly added into the stirring barrel, and the stirring speed was increased to 4000 r / min for 10 seconds. The sponge slurry after stirring was injected into a mold to form a sponge blank, which was aged at room temperature for 48 h, and then cut into small pieces of photocatalytically active hydrophilic sponge material. The physical properties and photocatalytic performance of the product were detected. Comparative Example 1

[0046] This comparative example is different from Example 6 in that the titanium cobalt composite oxide photocatalyst powder prepared in Example 3, 44 g, was replaced with the same amount of titanium cobalt composite oxide photocatalyst powder prepared in Example 1. Photocatalytically active hydrophilic sponge was prepared by the same method, and then aged. After aging, the photocatalytically active hydrophilic sponge material was cut into small pieces. The physical properties and photocatalytic performance of the product were detected. Comparative Example 2

[0047] This comparative example is different from Example 6 in that the titanium cobalt composite oxide photocatalyst powder prepared in Example 3, 44 g, was replaced with the same amount of titanium cobalt composite oxide photocatalyst powder prepared in Example 2. Photocatalytically active hydrophilic sponge was prepared by the same method, and then aged. After aging, the photocatalytically active hydrophilic sponge material was cut into small pieces. The physical properties and photocatalytic performance of the product were detected. Comparative Example 3

[0048] The comparative example is compared with example 6, the difference is that the titanium cobalt composite oxide photocatalyst powder 44 grams prepared in example 3 is replaced by the same mass and fineness, and the TiO2 photocatalyst commonly used in the prior art, and the hydrophilic sponge is prepared by the same method, and after aging, it is cut into small pieces. Sample detection of product physical properties and photocatalytic performance.

[0049] The photocatalytic active hydrophilic sponge prepared is sampled and detected, all examples and comparative examples have hydrophilic properties, and the hydrophilicity is relatively strong; compared with the hydrophilic sponge of comparative example 3 without adding the titanium cobalt composite oxide photocatalyst powder proposed in the application, all hydrophilic sponges added with the titanium cobalt composite oxide photocatalyst powder proposed in the application show good photocatalytic performance under visible light, and the tear strength, hydrophilicity and photocatalytic performance of the product are comprehensively considered, and example 6 is a preferred case.

[0050] The above shows and describes the basic principles and main features of the application and the advantages of the application. Those skilled in the art should understand that the application is not limited to the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the application, and various changes and improvements can be made without departing from the spirit and scope of the application, and these changes and improvements all fall within the scope of the application. The scope of protection of the application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a photocatalytically active hydrophilic sponge, characterized in that, Includes the following steps: (1) Preparation of titanium cobalt composite oxide photocatalyst powder: dissolve titanium tetrachloride in solvent to obtain solution A; dissolve CoCl2•6H2O in solvent to obtain solution B; then mix solution B and solution A evenly under low speed stirring at 100~150r / min; while maintaining low speed stirring, add 10~15% ammonia water dropwise to the mixture until no precipitate is visible at the drop point, continue stirring for 5~6 minutes, let stand, centrifuge and filter to obtain filter residue, wash the filter residue with 55~65% ethanol, compress to obtain solid filter cake, place the solid filter cake in a constant temperature oven, dry at 100~120℃ for 3~5 hours, then calcine at 350~450℃ for 4~6 hours, cool to room temperature, grind and sieve to obtain 300~400 mesh titanium cobalt composite oxide photocatalyst powder; (2) Preparation of photocatalytic active hydrophilic sponge: The titanium cobalt composite oxide photocatalyst powder obtained in step (1) is mixed with polyether polyol to form a slurry. Then, under stirring at 500~600r / min, hydrophilic polyol, hydrophilic additive, foam stabilizer, foaming agent, pore opener and catalyst are injected into the mixing tank in sequence and stirred evenly. Then, diisocyanate is added and stirred at 4000~4500r / min for 10~12 seconds. The mixture is then injected into a mold to form a sponge blank and matured at room temperature for 36~48h to obtain the product. In step (1), solution B is mixed with solution A, and the molar ratio of titanium tetrachloride and CoCl2•6H2O in the resulting mixed solution is 1:1.5 ~ 1.5:

1.

2. The method for preparing a photocatalytically active hydrophilic sponge according to claim 1, characterized in that: In step (1), the solvent is composed of isopropanol and deionized water. In solution A, the mass ratio of titanium tetrachloride, isopropanol and deionized water is 190:50 to 80:

500. In solution B, the mass ratio of CoCl2•6H2O, isopropanol and deionized water is 240:50 to 80:

500.

3. The method for preparing a photocatalytically active hydrophilic sponge according to claim 1, characterized in that: In step (2), the mass fractions of each component are as follows: 40-80 parts of polyether polyol, 20-60 parts of hydrophilic polyol, 10-15 parts of hydrophilic additive, 2-4 parts of foam stabilizer, 15-25 parts of titanium cobalt composite oxide photocatalyst powder, 3-6 parts of pore opener, 2-4 parts of foaming agent, 1-2 parts of catalyst, and 35-60 parts of diisocyanate.

4. The method for preparing a photocatalytically active hydrophilic sponge according to claim 1, characterized in that: In step (2), the hydrophilic polyol is a polyether or polyester polyol in which the ratio of monomer ethylene oxide to propylene oxide is greater than 50% in the synthesis, the functionality is 2 to 4, and the average molecular weight is 500 to 5000.

5. The method for preparing a photocatalytically active hydrophilic sponge according to claim 1, characterized in that: In step (2), the polyether polyol is a common flexible foam polyether.

6. The method for preparing a photocatalytically active hydrophilic sponge according to claim 1, characterized in that: In step (2), the hydrophilic additive is a non-hydrolyzed silicone oil with polyether as the main chain and silicon-terminated ends.

7. The method for preparing a photocatalytically active hydrophilic sponge according to claim 1, characterized in that: In step (2), the foam stabilizer is a combination of silicone-terminated hydrophilic silicone oil and open-cell flexible foam silicone oil; the foaming agent is deionized water.

8. The method for preparing a photocatalytically active hydrophilic sponge according to claim 1, characterized in that: In step (2), the catalyst is composed of one or more of organotin catalysts, organobismuth catalysts, and amine catalysts.

9. The method for preparing a photocatalytically active hydrophilic sponge according to claim 1, characterized in that: In step (2), the diisocyanate is one or more of TD80I, modified MDI8019, modified MDI8223, and polymeric MDIPM200.