Photocatalyst for efficiently removing printing and dyeing VOCs (Volatile Organic Compounds) as well as preparation method and application of photocatalyst

Abstract

The invention belongs to the technical field of air purification materials, and particularly relates to a photocatalyst for efficiently removing printing and dyeing VOCs and a preparation method and application thereof.The method comprises the steps that tantalum salt, an organic solvent, polyether 123 and silver salt are evenly mixed according to a certain proportion to form a sol solution, the formed sol solution is aged in air to generate a sol-gel sample, and the sol-gel sample is placed in a drying oven to be dried; the tantalum salt is one of tantalum ethoxide, tantalum chloride and tantalum oxalate, the organic solvent is one or more of methyl alcohol, ethyl alcohol, propyl alcohol, n-butyl alcohol and isobutyl alcohol, and the silver salt is one of silver nitrate and silver acetate. The prepared catalyst is high in visible light response and mild in reaction condition, has good activity of photocatalytic degradation of VOCs, and can effectively improve the degradation rate of VOCs.

Description

Technical Field

[0001] The present invention belongs to the technical field of air purification materials, and in particular relates to a photocatalyst for efficiently removing VOCs from printing and dyeing, and a preparation method and application thereof. Background Art

[0002] The printing and dyeing industry emits a large amount of volatile organic compounds (VOCs) during the production process. These compounds mainly come from the organic solvents used in the printing and dyeing process, such as cloth pre-treatment, dyeing, printing, finishing and finished product packaging. VOCs emissions involve almost all links. The types and compositions of VOCs pollutants emitted by the printing and dyeing industry are complex, mainly including benzene, toluene, xylene, formaldehyde, acetone, etc. These substances have potential hazards to human health and the environment. Therefore, the governance of VOCs in the printing and dyeing industry has become one of the important areas of concern for scientific researchers.

[0003] Nowadays, photocatalysis is considered a green and clean indoor purification technology because it can deeply oxidize pollutants into more environmentally friendly substances such as CO2 and H2O. Tantalum-based catalysts can effectively generate photogenerated electrons and holes due to their suitable band gap, and show good catalytic performance and application prospects in solar water decomposition to produce hydrogen. However, the application of tantalum in VOCs treatment is not involved in the existing technology. Summary of the invention

[0004] The purpose of the present invention is to solve the defects and shortcomings existing in the prior art, and to provide a photocatalyst for efficiently removing printing and dyeing VOCs and a preparation method and application thereof in order to better degrade printing and dyeing VOCs. The catalyst prepared by this method has a strong visible light response, mild reaction conditions, good photocatalytic degradation activity of VOCs, and can effectively improve the degradation rate of VOCs.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a photocatalyst for efficiently removing VOCs in printing and dyeing, comprising the following steps:

[0006] (1) mixing tantalum salt, organic solvent, polyether 123 and silver salt uniformly to form a sol solution;

[0007] (2) aging the sol solution to form a sol-gel sample;

[0008] (3) By heating and calcining the sol-gel sample, a photocatalyst that can efficiently remove VOCs from printing and dyeing can be obtained.

[0009] Preferably, the tantalum salt in step (1) is one of tantalum ethoxide, tantalum chloride and tantalum oxalate.

[0010] Preferably, the organic solvent in step (1) is one or more of methanol, ethanol, propanol, n-butanol and isobutanol.

[0011] Preferably, the silver salt in step (1) is one of silver nitrate and silver acetate.

[0012] Preferably, in step (1), the mass ratio of tantalum salt to organic solvent is 1:10-1:50.

[0013] Preferably, in step (1), the mass ratio of the organic solvent to the polyether 123 is 1:10-1:100.

[0014] Preferably, the molar ratio of tantalum salt to silver salt in step (1) is 20:1-100:1.

[0015] Preferably, in step (2), the aging temperature is 20-70° C., and the aging time is 24-96 h. In step (3), the calcination temperature is 300-700° C., and the calcination time is 3-8 h.

[0016] A photocatalyst for efficiently removing printing and dyeing VOCs prepared by the above preparation method, the catalyst is evenly dispersed, has good visible light response performance, and the oxygen vacancies introduced into the catalyst structure can be used as active sites, which is beneficial to the degradation and removal of VOCs.

[0017] Preferably, the space to which the above-mentioned chemical is applicable includes but is not limited to the printing and dyeing factory environment, and can also be used for the removal of outdoor VOCs.

[0018] After adopting the above technical solution, the photocatalyst for efficiently removing printing and dyeing VOCs and its preparation method and application provided by the present invention have the following beneficial effects:

[0019] (1) The preparation method provided by the present invention adopts a simple sol-gel method, is simple to operate, has high purity of the target product, and can achieve large-scale synthesis;

[0020] (2) The silver-doped tantalum-based catalyst provided by the present invention can effectively improve the response capability to visible light and improve the carrier separation efficiency;

[0021] (3) The silver doped in the present invention has a suitable band gap and adjustable photoelectric properties, so that the catalytic performance of the obtained photocatalytic material is effectively enhanced, thereby improving the degradation efficiency of VOCs.

[0022] (4) The preparation method provided by the present invention is simple, and the obtained material is easy to use, environmentally friendly, and is conducive to promotion in industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1XRD spectra of materials prepared in Examples 1 and 2 of the present invention;

[0024] Figure 2 These are the SEM images of samples of Examples 1 and 2 of the present invention (a: Ag-Ta2O5-1, b: Ag-Ta2O5-2). DETAILED DESCRIPTION

[0025] The present invention is further described clearly and completely below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that any process not specifically described below can be implemented or understood by a person skilled in the art with reference to the prior art. Reagents or instruments used without indicating the manufacturer are considered to be conventional products that can be purchased commercially.

[0027] Example 1

[0028] Take 5g of polyether P123 and dissolve it in 50g of ethanol, add 0.005mol of tantalum chloride and 0.04g of silver nitrate, stir at room temperature, and after it is dissolved, age the obtained sol solution at 40°C for 48h, then calcine at 400°C for 4h, and then further calcine at 600°C for 1h to obtain silver-doped Ag-Ta2O5-1.

[0029] Figure 1-2 The XRD spectrum and SEM image of the sample in Example 1 are included respectively.

[0030] Example 2

[0031] Take 2.5g of polyether P123 and dissolve it in 50g of ethanol, stir for 0.5h, add 0.005mol of tantalum chloride and 0.06g of silver nitrate, stir at room temperature for 1.5h, after it is dissolved, the obtained sol solution is aged at 40℃ for one week to obtain a transparent gel, and then the gel is kept at 250℃ for 12h, and then further calcined at 450℃ for 4h to obtain silver-doped mesoporous Ag-Ta2O5-2.

[0032] Figure 1-2 The XRD spectrum and SEM image of the sample in Example 2 are included respectively.

[0033] Example 3

[0034] Take 5g of polyether P123 and dissolve it in 50g of ethanol, stir for 0.5h, add 0.01mol of tantalum ethanol and 0.2g of silver nitrate, stir at room temperature for 2.0h to obtain a transparent sol solution, age it at room temperature for 48h to obtain a transparent gel, then calcine the gel at 400℃ for 4h and then at 600℃ for 0.5h to obtain silver-doped Ag-Ta2O5-3.

[0035] Example 4

[0036] Take 5g of polyether P123 and dissolve it in 50g of isopropanol, stir for 0.5h, add 0.01mol of tantalum ethanol and 0.2g of silver nitrate, stir at room temperature for 2.0h to obtain a transparent sol solution, age it at room temperature for 48h to obtain a transparent gel, then calcine the gel at 400℃ for 4h and then at 600℃ for 0.5h to obtain silver-doped Ag-Ta2O5-4.

[0037] Example 5

[0038] Take 5g of polyether P123 and dissolve it in 50g of isopropanol, stir for 1.0h, add 0.01mol of tantalum ethanol and 0.4g of silver nitrate, stir at room temperature for 2.0h to obtain a transparent sol solution, age it at room temperature for 36h to obtain a transparent gel, then calcine the gel at 400℃ for 4h and then at 700℃ for 0.5h to obtain silver-doped Ag-Ta2O5-5.

[0039] The photocatalytic activity of the catalyst was analyzed by photocatalytic degradation of specific VOCs. The representative pollutants used in the experiment were toluene, formaldehyde and ethyl acetate. The photocatalytic reaction vessel was 12.5×2×4cm 3 (100mL) quartz colorimetric cell, spread an appropriate amount of photocatalyst on the bottom of the colorimetric cell, use a microinjector to take the prepared pollutant solution of the selected concentration and inject it into the colorimetric cell, seal the colorimetric cell with high vacuum silicone grease, and treat it in the dark for 30 minutes to allow the pollutants to fully evaporate into the gas phase and reach adsorption-desorption equilibrium with the catalyst.

[0040] The photocatalytic process uses a 300W xenon lamp to simulate sunlight, the current is constant at 15A, the illumination time is 1h, the sampling interval is 10min, and toluene, methanol and ethyl acetate have optimal absorption wavelengths at 204nm, 415nm and 210nm, respectively. Using this characteristic, ultraviolet spectrophotometry is used to detect changes in the absorbance of gaseous pollutants in real time, and the removal rate of pollutants is calculated based on the Lambert-Beer law.

[0041] The colorimetric cell was placed under a xenon lamp for 1 hour, and the concentration changes of toluene were measured every 10 minutes. Without adding a catalyst, the concentration of gas phase toluene basically did not change, and it dropped by 6% after 1 hour. After adding Ag-Ta2O5-1, the concentration of gas phase toluene dropped rapidly, and the degradation rate of toluene was 90% after 1 hour, and the degradation rate could reach 98% after 2 hours, indicating that the Ag-Ta2O5-1 catalyst has a good degradation effect on gas phase toluene.

[0042] The same method was used to measure the degradation performance of formaldehyde. Without adding a catalyst, the concentration of gaseous formaldehyde did not change significantly, and decreased by 8% after 1 hour. When Ag-Ta2O5-1 was added, the concentration of gaseous formaldehyde decreased rapidly, and the formaldehyde degradation rate was 85% after 0.5 hours, and the degradation rate could reach 98% after 1.5 hours, indicating that the Ag-Ta2O5-1 catalyst also showed a good degradation effect on gaseous formaldehyde.

[0043] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a photocatalyst for efficiently removing VOCs from printing and dyeing, characterized in that: The steps include: (1) mixing tantalum salt, organic solvent, polyether 123 and silver salt uniformly to form a sol solution; (2) aging the sol solution to form a sol-gel sample; (3) By heating and calcining the sol-gel sample, a photocatalyst that can efficiently remove VOCs from printing and dyeing can be obtained.

2. The method for preparing a photocatalyst for efficiently removing VOCs in printing and dyeing according to claim 1, characterized in that: In the step (1), the tantalum salt is one of tantalum ethoxide, tantalum chloride and tantalum oxalate.

3. The method for preparing a photocatalyst for efficiently removing VOCs in printing and dyeing according to claim 1, characterized in that: The organic solvent in step (1) is one or more of methanol, ethanol, propanol, n-butanol and isobutanol.

4. The method for preparing a photocatalyst for efficiently removing VOCs in printing and dyeing according to claim 1, characterized in that: The silver salt in step (1) is one of silver nitrate and silver acetate.

5. The method for preparing a photocatalyst for efficiently removing VOCs in printing and dyeing according to claim 1, characterized in that: In the step (1), the mass ratio of tantalum salt to organic solvent is 1:10-1:

50.

6. The method for preparing a photocatalyst for efficiently removing VOCs in printing and dyeing according to claim 1, characterized in that: In the step (1), the mass ratio of the organic solvent to the polyether 123 is 1:10-1:

100.

7. The method for preparing a photocatalyst for efficiently removing VOCs in printing and dyeing according to claim 1, characterized in that: The molar ratio of tantalum salt to silver salt in step (1) is 20:1-100:

1.

8. The method for preparing a photocatalyst for efficiently removing VOCs in printing and dyeing according to claim 1, characterized in that: In the step (2), the aging temperature is 20-70° C., and the aging time is 24-96 hours. In the step (3), the roasting temperature is 300-700° C., and the roasting time is 3-8 hours.

9. A photocatalyst for efficiently removing VOCs in printing and dyeing prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the photocatalyst for efficiently removing VOCs in printing and dyeing as claimed in claim 9 in removing VOCs.

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