Photocatalytic self-cleaning glass and preparation method thereof
阅读说明：本技术 一种光催化自清洁玻璃及其制备方法 (Photocatalytic self-cleaning glass and preparation method thereof ) 是由 鲁福身 游耿书 陈冬青 刘宇星 杨文欣 夏红 于 2020-11-06 设计创作，主要内容包括：本发明公开了一种光催化自清洁玻璃的制备方法,包括如下工艺步骤：1)将g-C-3N-4和强碱分散于去离子水中,得CNNS白色分散液,过滤、洗涤、真空干燥；2)在容器A中加入去离子水和CNNS,配制成A溶液,在容器B中加入去离子水和PDDA,制成B溶液；3)取经表面羟基化处理后的玻璃基材,依次经过B溶液浸泡、去离子水洗涤、A溶液浸泡,实现一层PDDA-CNNS纳米薄膜堆积；多次重复堆积形成多层PDDA-CNNS纳米薄膜。本发明通过层层静电自组装方式在玻璃基材上构建多层PDDA-CNNS纳米薄膜,有利于该自清洁表面光生电子与空穴的分离,进一步提高了g-C-3N-4材料的光催化能力,且制备过程中不含有过渡金属,其工艺步骤简单、环保无毒。(The invention discloses a preparation method of photocatalytic self-cleaning glass, which comprises the following process steps: 1) g to C 3 N 4 Dispersing strong base in deionized water to obtain CNNS white dispersion, filtering, washing, and vacuum drying; 2) adding deionized water and CNNS into a container A to prepare a solution A, and adding deionized water and PDDA into a container B to prepare a solution B; 3) taking the glass substrate subjected to surface hydroxylation treatment, and sequentially soaking the glass substrate in a solution B, washing the glass substrate with deionized water and soaking the glass substrate in a solution A to realize the accumulation of a layer of PDDA-CNNS nano film; and repeatedly stacking for multiple times to form a multilayer PDDA-CNNS nano film. The invention constructs a plurality of layers of PDDA-CNNS nano films on the glass substrate in a layer-by-layer electrostatic self-assembly mode, is beneficial to the separation of the photoproduction electrons and the holes on the self-cleaning surface, and further improves the g-C 3 N 4 The material has photocatalysis capacity, and the preparation process does not contain transition metal, and the process has simple steps, environmental protection and no toxicity.)
1. A preparation method of photocatalytic self-cleaning glass is characterized by comprising the following process steps:
1) preparing CNNS: g to C3N4Dispersing with strong base in deionized water, ultrasonically stirring, refluxing for 3-5 hr to obtain uniformly dispersed white CNNS dispersion, filtering, washing, and vacuum drying to obtain CNNS;
2) preparing A, B solution: adding deionized water and the CNNS obtained in the step 1) into a container A, carrying out ultrasonic treatment and mixing to prepare a solution A with the CNNS concentration of 1-5g/L, adding deionized water and PDDA into a container B, and mixing to prepare a solution B with the PDDA concentration of 1-5 g/L;
3) constructing a composite material: placing the glass substrate subjected to surface hydroxylation treatment in the solution B for 15-20min, washing with deionized water, and placing in the solution A for 15-20min to realize the accumulation of a layer of PDDA-CNNS nano film; repeatedly piling for many times to form a plurality of layers of PDDA-CNNS nano films, and then drying to obtain the photocatalytic self-cleaning glass.
2. The method for preparing the photocatalytic self-cleaning glass as claimed in claim 1, wherein the method comprises the following steps: in the step 3), the surface hydroxylation treatment is to soak the glass substrate in a mixed solution prepared from concentrated sulfuric acid and 30% hydrogen peroxide according to the volume ratio of (2.3-9):1 at the temperature of 80-100 ℃ for 1-2 h.
3. The method for preparing the photocatalytic self-cleaning glass as claimed in claim 1, wherein the method comprises the following steps: the number of the layers repeatedly stacked to form the multiple layers of PDDA-CNNS nano films in the step 3) is 8.
4. The method for preparing the photocatalytic self-cleaning glass as claimed in claim 1, wherein the method comprises the following steps: g to C in step 1)3N4And the addition amount of the strong base is 1 (3-4) in mass ratio.
5. The method for preparing the photocatalytic self-cleaning glass as claimed in claim 1, wherein the method comprises the following steps: g to C in step 1)3N4The preparation method comprises the steps of placing melamine in a muffle furnace, controlling the heating rate to be 3-5 ℃/min, calcining for 3-5h at the temperature of 500-550 ℃, and cooling to obtain a light yellow solid.
6. A photocatalytic self-cleaning glass, characterized by being prepared by the preparation method of any one of claims 1 to 5.
Technical Field
The invention belongs to the field of composite materials, and particularly relates to a photocatalytic self-cleaning composite material.
Background
The photocatalyst, such as common oxide sulfide semiconductors like titanium dioxide, zinc oxide, tin oxide, zirconium dioxide, cadmium sulfide, etc., generates photo-generated electron-hole pairs in situ in the photocatalyst under the action of light, and the photo-generated holes can be in the medium (O)2、H2O) or directly acts on various organic matters to carry out oxidative decomposition on the organic matters. Therefore, the photocatalyst is widely applied to photocatalytic degradation, sterilization, deodorization, antifouling and self-cleaning.
At present, the photocatalysis self-cleaning glass is mainly formed by constructing a doped or undoped titanium dioxide nano film on the surface of glass by methods such as chemical vapor deposition, evaporation and the like. The nanometer surface constructed by the method inevitably causes coexistence of a plurality of titanium dioxide crystal forms, wherein only anatase type titanium dioxide has photocatalytic activity and low photocatalytic efficiency, and the relatively complex process also causes higher cost.
Graphite-like phase carbonitrides, i.e. g-C3N4And is a typical polymer semiconductor having a monoatomic layer structure and a suitable forbidden band width. In recent years g-C3N4Has received increasing attention in the field of photocatalysis, as compared to conventional titanium dioxide, g-C3N4Can effectively activate molecular oxygen to generate superoxide radical for photocatalytic degradation of organic pollutants, and g-C3N4The compound has the characteristic of low biological toxicity, and tests show that the acute oral toxicity LD50 of SPF-grade KM mice is more than 5000mg/kg & BW, belongs to an actual nontoxic material, is environment-friendly, and has no secondary pollution.
With the development of society, the photocatalytic self-cleaning material is gradually known and applied by human beings, and based on the fact that metal oxides such as titanium dioxide and sulfide semiconductors are easy to cause secondary pollution to the environment in the practical application and production process, and semiconductor materials such as cadmium sulfide have high biotoxicity and harm the health of users, the g-C is used3N4The photocatalytic material is hopeful to become a self-cleaning composite material by replacing the traditional transition metal semiconductor photocatalytic materialThe research trend of materials. However, the polymer semiconductor cannot be surface-coated by a method such as vapor deposition as in the case of the transition metal semiconductor. Therefore, how to utilize g-C3N4The self-cleaning composite material with excellent photocatalytic effect is prepared in a simple and environment-friendly manner, and has great significance and practical value.
Disclosure of Invention
The invention aims to provide photocatalytic self-cleaning glass and a preparation method thereof, aiming at overcoming the defects of the prior art.
The technical scheme adopted by the invention is as follows: a preparation method of photocatalytic self-cleaning glass comprises the following process steps:
1) preparation of CNNS (carbon nitride nanosheet): g to C3N4Dispersing with strong base in deionized water, ultrasonically stirring, refluxing for 3-5 hr to obtain uniformly dispersed white CNNS dispersion, filtering, washing, and vacuum drying to obtain CNNS;
2) preparing A, B solution: adding deionized water and the CNNS obtained in the step 1) into a container A, performing ultrasonic treatment, mixing and preparing into a solution A with the CNNS concentration of 1-5g/L, adding deionized water and PDDA (poly diallyl dimethyl ammonium chloride) into a container B, and mixing and preparing into a solution B with the PDDA concentration of 1-5 g/L;
3) constructing a composite material: placing the glass substrate subjected to surface hydroxylation treatment in the solution B for 15-20min, washing with deionized water, and placing in the solution A for 15-20min to realize the accumulation of a layer of PDDA-CNNS nano film; repeatedly piling for many times to form a plurality of layers of PDDA-CNNS nano films, and then drying to obtain the photocatalytic self-cleaning glass.
The g-C can be controlled by fully ultrasonic stirring and refluxing in the step 1)3N4The degree of exfoliation, and thus its degradability. The proper A, B solution soaking time in the step 3) ensures the adsorption effect of CNNS and PDDA.
As a further improvement of the scheme, the step 3) of surface hydroxylation treatment is to soak the glass substrate in a mixed solution of concentrated sulfuric acid and 30% hydrogen peroxide at a temperature of 80-100 ℃ for 1-2h according to a volume ratio of (2.3-9): 1. Specifically, after hydroxylation treatment, quartz glass is anionized and is more likely to be electrostatically adsorbed by polycation PDDA. The temperature of the mixed solution is well controlled in the hydroxylation treatment process, the reaction is too slow due to too low temperature, and the solution is easy to boil and splash due to too high temperature. Meanwhile, the soaking needs to ensure sufficient duration, so as to avoid incomplete hydroxylation.
As a further improvement of the above scheme, the number of the layers repeatedly stacked in the step 3) to form the multilayer PDDA-CNNS nano-film is 8. Specifically, the ultraviolet absorption spectrum characterization shows that the increase and change of the absorption capacity are not obvious when more than 8 layers are stacked, and 8 layers are obtained to be the most economical and have the near-optimal self-cleaning degradation capacity.
As a further improvement of the above, said g-C in step 1)3N4And the addition amount of the strong base is 1 (3-4) in mass ratio. Specifically, when the alkali concentration is too low, sufficient peeling is difficult, and as the alkali concentration increases, the peeling effect is better. However, the excessive alkali concentration not only causes the wastewater in the production process to be difficult to treat, but also can destroy the structure of carbon nitride and influence the performance of the nano-sheets. Among them, the strong base is preferably sodium hydroxide. In particular, potassium hydroxide can be used in the experimental process, but is expensive compared with sodium hydroxide, and is difficult to be widely used in the production process.
As a further improvement of the above, said g-C in step 1)3N4The preparation method comprises the steps of placing melamine in a muffle furnace, controlling the heating rate to be 3 ℃/min, calcining for 3h at the temperature of 550 ℃, and cooling to obtain a light yellow solid. Specifically, at this temperature rise rate, calcination temperature and calcination time, the resulting carbon nitride has optimum release properties.
The other technical scheme adopted by the invention is as follows: the photocatalytic self-cleaning glass is prepared by the preparation method.
The invention has the beneficial effects that:
the invention constructs a multilayer PDDA-CNNS nano film on a glass substrate in a layer-by-layer electrostatic self-assembly mode, wherein the PDDA not only plays the role ofThe accumulation effect improves the hydrophilic ability of the self-cleaning surface, is beneficial to the separation of the photoproduction electrons and the holes of the self-cleaning surface, and further improves the g-C3N4The material has photocatalysis capacity, and the preparation process does not contain transition metal, and the process has simple steps, environmental protection and no toxicity.
The photocatalytic self-cleaning glass prepared by the method has excellent degradation capability on common color pollution in life and excellent photocatalytic self-cleaning performance.
Drawings
FIG. 1 shows the result of the photocatalytic self-cleaning performance test of example 1;
FIG. 2 is a test result of the photocatalytic self-cleaning performance test of comparative example 1;
FIG. 3 is a test result of the photocatalytic self-cleaning performance test of comparative example 2;
FIG. 4 shows the result of the photocatalytic self-cleaning performance test of example 2;
FIG. 5 shows the result of the photocatalytic self-cleaning performance test of example 3.
Detailed Description
The present invention is specifically described below with reference to examples in order to facilitate understanding of the present invention by those skilled in the art. It should be particularly noted that the examples are given solely for the purpose of illustration and are not to be construed as limitations on the scope of the invention, as non-essential improvements and modifications to the invention may occur to those skilled in the art, which fall within the scope of the invention as defined by the appended claims. Meanwhile, the raw materials mentioned below are not specified in detail and are all commercial products; the process steps or preparation methods not mentioned in detail are all process steps or preparation methods known to the person skilled in the art.
Example 1
A preparation method of photocatalytic self-cleaning glass comprises the following process steps:
1) preparing CNNS: g to C3N4Dispersing in deionized water at a mass ratio of 1:4 with sodium hydroxide, ultrasonically stirring and refluxing for 3h to obtain dispersionFiltering, washing and vacuum drying the uniform CNNS white dispersion liquid to obtain CNNS;
2) preparing A, B solution: adding deionized water and the CNNS obtained in the step 1) into a container A, carrying out ultrasonic treatment and mixing to prepare a solution A with the CNNS concentration of 3.2g/L, adding deionized water and PDDA into a container B, and mixing to prepare a solution B with the PDDA concentration of 1 g/L;
3) constructing a composite material: and (3) placing the glass substrate subjected to surface hydroxylation treatment in the solution B for 15min, washing with deionized water, placing in the solution A for 15min, finishing the accumulation of the first layer of PDDA-CNNS nano film, repeatedly accumulating to form 8 layers of PDDA-CNNS nano films, and drying to obtain the photocatalytic self-cleaning glass in the embodiment 1.
Wherein, in this example, g-C is described in step 1)3N4The preparation method comprises placing melamine in a muffle furnace, controlling the heating rate at 3 deg.C/min, calcining at 550 deg.C for 3 hr, and cooling to obtain light yellow g-C3N4A solid; in the step 3) of this embodiment, the surface hydroxylation treatment is to immerse the glass substrate in a mixed solution of concentrated sulfuric acid and 30% hydrogen peroxide at 85 ℃ in a volume ratio of 2.33:1 for 2 hours.
Three samples of the photocatalytic self-cleaning glass in the embodiment 1 are taken to carry out a photocatalytic self-cleaning performance test, specifically, 10ml of rhodamine solution, 10ml of methyl orange solution and 10ml of orange juice are respectively dripped on the surfaces of the three samples, then the polluted samples are simultaneously moved to the sunlight of ten points in the morning, the absorbance change of dye pollutants is measured every three hours, the relative intensity of the absorbance represents the change of the pollutant concentration, and the obtained test result is shown in the attached figure 1, wherein the ordinate is the relative intensity of the absorbance, and the unit is 100%; the abscissa is the interval time in hours. Test results show that the photocatalytic self-cleaning glass prepared by the method can be used for photocatalytic degradation of common organic dyes in life under sunlight, and the photocatalytic self-cleaning glass is excellent in photocatalytic self-cleaning performance.
Comparative example 1
Ordinary quartz glass was used as comparative example 1
Taking three quartz glass samples to carry out photocatalytic self-cleaning performance test, specifically dropping 10ml of rhodamine solution, 10ml of methyl orange solution and 10ml of orange juice on the surfaces of the three samples respectively, then moving the polluted samples to the sunlight of ten points in the morning simultaneously, measuring the absorbance change of dye pollutants every three hours, wherein the relative intensity of absorbance represents the change of pollutant concentration, and the obtained test result is shown in figure 2, wherein the ordinate is the relative intensity of absorbance, and the unit is 100%; the abscissa is the interval time in hours.
Comparative example 2
Single-layer PDDA-CNNS glass as comparative example 2
1) Preparing CNNS: g to C3N4Dispersing the CNNS and sodium hydroxide in deionized water according to the mass ratio of 1:4, ultrasonically stirring and refluxing for 3 hours to obtain uniformly dispersed CNNS white dispersion, and filtering, washing and vacuum drying to obtain CNNS;
2) preparing A, B solution: adding deionized water and the CNNS obtained in the step 1) into a container A, carrying out ultrasonic treatment and mixing to prepare a solution A with the CNNS concentration of 3.2g/L, adding deionized water and PDDA into a container B, and mixing to prepare a solution B with the PDDA concentration of 1 g/L;
3) constructing a composite material: and (3) taking the glass substrate subjected to surface hydroxylation treatment, sequentially placing the glass substrate in the solution B for 15min, washing the glass substrate with deionized water, placing the glass substrate in the solution A for 15min to finish the first layer of PDDA-CNNS nano film accumulation, and drying the film to obtain the photocatalytic self-cleaning glass in the practical example 2.
Wherein, g to C are as described in step 1) of this comparative example3N4The preparation method comprises the steps of placing melamine in a muffle furnace, controlling the heating rate to be 3 ℃/min, calcining for 3h at the temperature of 550 ℃, and cooling to obtain light yellow g-C3N4 solid; in the step 3) of this embodiment, the surface hydroxylation treatment is to immerse the glass substrate in a mixed solution of concentrated sulfuric acid and 30% hydrogen peroxide at 85 ℃ in a volume ratio of 2.33:1 for 2 hours.
Taking three samples of the photocatalytic self-cleaning glass in the comparative example 2 for testing the photocatalytic self-cleaning performance, specifically dropping 10ml of rhodamine solution, 10ml of methyl orange solution and 10ml of orange juice on the surfaces of the three samples, then moving the polluted samples to the sunlight of ten points in the morning simultaneously, measuring the absorbance change of dye pollutants every three hours, wherein the relative intensity of the absorbance represents the change of the concentration of the pollutants, and the obtained test result is shown in the attached figure 3, wherein the ordinate is the relative intensity of the absorbance, and the unit is 100%; the abscissa is the interval time in hours.
Example 2
A preparation method of photocatalytic self-cleaning glass comprises the following process steps:
1) preparing CNNS: g to C3N4Dispersing the CNNS and strong base in deionized water according to the mass ratio of 1:3, ultrasonically stirring and refluxing for 3.5h to obtain uniformly dispersed CNNS white dispersion, and filtering, washing and vacuum drying to obtain CNNS;
2) preparing A, B solution: adding deionized water and the CNNS obtained in the step 1) into a container A, carrying out ultrasonic treatment and mixing to prepare a solution A with the CNNS concentration of 4g/L, adding deionized water and PDDA into a container B, and mixing to prepare a solution B with the PDDA concentration of 1 g/L;
3) constructing a composite material: and (3) placing the glass substrate subjected to surface hydroxylation treatment in the solution B for 20min, washing with deionized water, and placing in the solution A for 20min in sequence to finish the stacking of the first layer of PDDA-CNNS nano film, repeatedly stacking to form 12 layers of PDDA-CNNS nano films, and drying to obtain the photocatalytic self-cleaning glass in the embodiment 2.
Wherein, in this example, g-C is described in step 1)3N4The preparation method comprises placing melamine in a muffle furnace, controlling the heating rate at 5 deg.C/min, calcining at 500 deg.C for 5 hr, and cooling to obtain yellowish g-C3N4A solid; in the step 3) of this embodiment, the surface hydroxylation treatment is to immerse the glass substrate in a mixed solution of concentrated sulfuric acid and 30% hydrogen peroxide at 80 ℃ in a volume ratio of 9:1 for 1 hour.
Three samples of the photocatalytic self-cleaning glass in the embodiment 2 are taken for photocatalytic self-cleaning performance test, specifically, 10ml of rhodamine solution, 10ml of methyl orange solution and 10ml of orange juice are respectively dripped on the surfaces of the three samples, then the polluted samples are simultaneously moved to the sunlight of ten points in the morning, the absorbance change of the polluted samples is measured every three hours, and the obtained test result is shown in the attached figure 4, wherein the ordinate is the relative intensity of absorbance, and the unit is 100%; the abscissa is the interval time in hours. Test results show that the photocatalytic self-cleaning glass prepared by the method can be used for photocatalytic degradation of common organic dyes in life under sunlight, and the photocatalytic self-cleaning glass is excellent in photocatalytic self-cleaning performance.
Example 3
A preparation method of photocatalytic self-cleaning glass comprises the following process steps:
1) preparing CNNS: g to C3N4Dispersing the CNNS and strong base in deionized water according to the mass ratio of 1:3.5, ultrasonically stirring and refluxing for 5 hours to obtain uniformly dispersed CNNS white dispersion, and filtering, washing and vacuum drying to obtain CNNS;
2) preparing A, B solution: adding deionized water and the CNNS obtained in the step 1) into a container A, carrying out ultrasonic treatment and mixing to prepare a solution A with the CNNS concentration of 5g/L, adding deionized water and PDDA into a container B, and mixing to prepare a solution B with the PDDA concentration of 2 g/L;
3) constructing a composite material: and (3) placing the glass substrate subjected to surface hydroxylation treatment in the solution B for 20min, washing with deionized water, and placing in the solution A for 20min in sequence to finish the stacking of the first layer of PDDA-CNNS nano film, repeatedly stacking to form 10 layers of PDDA-CNNS nano films, and drying to obtain the photocatalytic self-cleaning glass in the embodiment 3.
Wherein, in this example, g-C is described in step 1)3N4The preparation method comprises placing melamine in a muffle furnace, controlling the heating rate at 4 deg.C/min, calcining at 520 deg.C for 4 hr, and cooling to obtain light yellow g-C3N4A solid; in the step 3) of this embodiment, the surface hydroxylation treatment is to immerse the glass substrate in a mixed solution of concentrated sulfuric acid and 30% hydrogen peroxide at 80 ℃ for 1.5 hours in a volume ratio of 5: 1.
Three samples of the photocatalytic self-cleaning glass in the embodiment 3 are taken to carry out a photocatalytic self-cleaning performance test, specifically, 10ml of rhodamine solution, 10ml of methyl orange solution and 10ml of orange juice are respectively dripped on the surfaces of the three samples, then the polluted samples are simultaneously moved to the sunlight of ten points in the morning, the absorbance change of the polluted samples is measured every three hours, and the obtained test result is shown in the attached figure 5, wherein the ordinate is the relative intensity of absorbance, and the unit is 100%; the abscissa is the interval time in hours. Test results show that the photocatalytic self-cleaning glass prepared by the method can be used for photocatalytic degradation of common organic dyes in life under sunlight, and the photocatalytic self-cleaning glass is excellent in photocatalytic self-cleaning performance.
The above embodiments are preferred embodiments of the present invention, and all similar processes and equivalent variations to those of the present invention should fall within the scope of the present invention.