Photocatalytic device with porous ceramic as carrier and preparation method and application thereof
阅读说明：本技术 一种以多孔陶瓷为载体的光催化器件及其制备方法和应用 (Photocatalytic device with porous ceramic as carrier and preparation method and application thereof ) 是由 李烨 刘儒平 赵慧庆 张会灵 肖莹莹 王梦珠 于 2021-01-11 设计创作，主要内容包括：本发明提供了一种以多孔陶瓷为载体的光催化器件及其制备方法和应用,涉及降解水中有机污染物用光催化器件技术领域。本发明提供的光催化器件,包括多孔陶瓷载体以及位于所述多孔陶瓷载体表面和内部微腔孔洞中的TiO-2/BiOCl复合薄膜光催化层。与常规TiO-2光催化相比,本发明提供的以多孔陶瓷为载体的光催化器件,多孔陶瓷载体表面和内部微腔孔洞中的TiO-2/BiOCl复合薄膜光催化层利用了层间空间较大的片状BiOCl纳米粉末掺杂,有利于TiO-2/BiOCl复合薄膜光催化层的光生电子和空穴对的分离,而且可以使吸收带发生红移,扩大光响应范围,提高光催化降解效率和太阳能利用率。催化反应后,器件易于从污水中分离、回收再利用。(The invention provides a photocatalytic device taking porous ceramic as a carrier, and a preparation method and application thereof, and relates to the technical field of photocatalytic devices for degrading organic pollutants in water. The invention provides a photocatalytic device, which comprises a porous ceramic carrier and TiO positioned on the surface of the porous ceramic carrier and in internal microcavity holes 2 the/BiOCl composite film photocatalysis layer. With conventional TiO 2 Compared with photocatalysis, the invention uses porous ceramics as carrierBulk photocatalytic device, porous ceramic support surface and TiO in internal microcavity pores 2 the/BiOCl composite film photocatalytic layer utilizes the doping of flaky BiOCl nano powder with larger interlayer space, and is beneficial to TiO 2 The separation of photo-generated electrons and hole pairs of the/BiOCl composite film photocatalytic layer can enable an absorption band to generate red shift, expand the photoresponse range and improve the photocatalytic degradation efficiency and the solar energy utilization rate. After the catalytic reaction, the device is easy to separate, recycle and reuse from the sewage.)
1. A photocatalytic device using porous ceramic as a carrier comprises a porous ceramic carrier and TiO positioned on the surface of the porous ceramic carrier and in internal micro-cavity holes2the/BiOCl composite film photocatalysis layer.
2. The photocatalytic device using porous ceramic as a carrier according to claim 1, wherein the porous ceramic carrier has a thickness of 30 to 700 μm; the volume density of the porous ceramic carrier is 0.5-1.6 g/cm3The pore volume of the porous ceramic carrier is 0.5-1.5 cm/g, and the pore diameter range of micro-cavity pores of the porous ceramic carrier is 150-3500 nm.
3. The porous ceramic supported photocatalytic device as set forth in claim 1, wherein the surface of the porous ceramic support and TiO in the micro-cavity pores inside the porous ceramic support2the/BiOCl composite film photocatalysis layerThe thickness is 50 to 1000 nm.
4. The photocatalytic porous-ceramic-supported device according to claim 1 or 3, wherein the surface of the porous ceramic support and TiO in the internal microcavity pores2The BiOCl mass fraction in the/BiOCl composite film photocatalysis layer is 0.1-6%.
5. The photocatalytic porous-ceramic-supported device according to claim 1 or 3, wherein the surface of the porous ceramic support and TiO in the internal microcavity pores2The particle size range of the flaky BiOCl nano powder in the/BiOCl composite film photocatalytic layer is 15-900 nm.
6. The method for preparing a photocatalytic device with porous ceramic as a carrier in any one of claims 1 to 5, comprising the steps of:
soaking the porous ceramic carrier in a titanium glue solution of flaky BiOCl nano powder to obtain a dipped porous ceramic; micro-cavity holes are formed on the surface and inside of the porous ceramic carrier;
and sintering the impregnated porous ceramic to obtain the photocatalytic device with the porous ceramic as a carrier.
7. The method according to claim 6, wherein the method for preparing the porous ceramic support comprises the steps of:
mixing silica gel and water, and carrying out hydrothermal reaction to obtain a porous ceramic carrier;
the pressure of the hydrothermal reaction is 20-1050 MPa, and the temperature of the hydrothermal reaction is 200-500 ℃; the time of the hydrothermal reaction is 10-240 min.
8. The preparation method according to claim 6, wherein the sintering temperature is 200-500 ℃, and the sintering time is 2-5 h.
9. Use of the porous ceramic supported photocatalytic device according to any one of claims 1 to 5 or the porous ceramic supported photocatalytic device obtained by the preparation method according to any one of claims 6 to 8 for removing organic pollutants from water.
Technical Field
The invention relates to the technical field of photocatalytic devices for removing organic matters in water, in particular to a photocatalytic device taking porous ceramic as a carrier and a preparation method and application thereof.
Background
The photocatalysis technology is widely applied to the treatment of organic pollutants in water environment. The solar energy is utilized to catalyze and degrade organic pollutants in water, and the sustainable development requirement of energy is met. Among the numerous semiconductor materials, TiO2Is the most commonly used photocatalyst, but TiO2Electron-hole pairs can be formed only under the irradiation of ultraviolet light, and the solar energy utilization rate is less than 5%; and TiO2The easy recombination of photogenerated electrons and holes results in low quantum yield and single TiO in the photocatalysis process2The use of photocatalysts has been limited, often by the incorporation of other nanomaterials with TiO2The modification is carried out by compounding, for example, the doping of the flaky nano material with larger interlayer space is utilized, so that the separation of photogenerated electrons and holes is facilitated, the red shift of an absorption band can be generated, the photoresponse range is expanded, and the photocatalytic degradation efficiency and the solar energy utilization rate are improved. In addition, the specific surface area and the porosity of the catalyst are also another effective way for improving the photocatalytic efficiency, the larger the specific surface area of the catalyst is, the more organic pollutants can be combined with the catalyst, the reaction speed is accelerated, and for the same catalyst, the catalytic activity of the porous material can be improved by several orders of magnitude compared with that of a common material. Most of the existing photocatalytic materials are powdery, and the powdery photocatalyst is difficult to separate and recycle after catalytic reaction. Therefore, a porous photocatalytic device easy to separate is researched and developed, the photocatalytic specific surface area is increased, the photoresponse range of a photocatalytic material is widened, and the photocatalysis is improvedThe efficiency and the solar energy utilization rate are the research hotspots in the field of photocatalytic degradation of organic pollutants.
Disclosure of Invention
The invention aims to provide a photocatalytic device taking porous ceramic as a carrier, and a preparation method and application thereof, compared with the conventional TiO2The invention provides a photocatalyst, and a photocatalytic device using porous ceramic as a carrier, which comprises a porous ceramic carrier and TiO positioned on the surface of the porous ceramic carrier and in micro-cavity holes inside the porous ceramic carrier2the/BiOCl composite film photocatalysis layer effectively reduces the recombination probability of electrons and holes, the photoresponse range can be expanded to visible light, the photocatalysis efficiency is improved, and devices are easy to recycle.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a photocatalytic device taking porous ceramic as a carrier, which comprises a porous ceramic carrier and TiO positioned on the surface of the porous ceramic carrier and in micro-cavity holes inside the porous ceramic carrier2the/BiOCl composite film photocatalysis layer.
Preferably, the thickness of the porous ceramic carrier is 30-700 μm; the volume density of the porous ceramic carrier is 0.5-1.6 g/cm3The pore volume of the porous ceramic carrier is 0.5-1.5 cm/g, and the pore diameter range of micro-cavity pores of the porous ceramic carrier is 150-3500 nm.
Preferably, TiO in the surface and the internal micro-cavity holes of the porous ceramic carrier2The thickness of the/BiOCl composite film photocatalysis layer is 50-1000 nm.
TiO on the surface of the porous ceramic carrier and in the internal microcavity holes2The BiOCl mass fraction in the/BiOCl composite film photocatalysis layer is 0.1-6%.
Preferably, TiO in the surface and the internal micro-cavity holes of the porous ceramic carrier2The particle size range of the flaky BiOCl nano powder in the/BiOCl composite film photocatalytic layer is 15-900 nm;
the invention provides a preparation method of a photocatalytic device with porous ceramic as a carrier, which comprises the following steps:
soaking the porous ceramic carrier in a titanium glue solution of flaky BiOCl nano powder to obtain a dipped porous ceramic; micro-cavity holes are formed on the surface and inside of the porous ceramic carrier;
and sintering the impregnated porous ceramic to obtain the photocatalytic device with the porous ceramic as a carrier.
Preferably, the preparation method of the porous ceramic carrier comprises the following steps:
mixing silica gel and water, and carrying out hydrothermal reaction to obtain a porous ceramic carrier;
the pressure of the hydrothermal reaction is 20-1050 MPa, and the temperature of the hydrothermal reaction is 200-500 ℃; the time of the hydrothermal reaction is 10-240 min.
Preferably, the sintering temperature is 200-500 ℃, and the sintering time is 2-5 h.
The invention provides an application of the photocatalytic device with porous ceramic as the carrier in the technical scheme or the photocatalytic device with porous ceramic as the carrier obtained by the preparation method in the technical scheme in removing organic pollutants in water.
The invention provides a photocatalytic device taking porous ceramic as a carrier, which comprises a porous ceramic carrier and TiO positioned on the surface of the porous ceramic carrier and the surface of an internal micro-cavity hole2the/BiOCl composite film photocatalysis layer. Pure TiO2The forbidden band width is 3.2eV, and generally, only ultraviolet light (< 400nm) can excite the material to generate photo-generated electrons and holes, thereby limiting the application of the material in the visible light range. The invention combines TiO2Characteristics of/BiOCl composite film and porous ceramics in TiO2The medium-composite BiOCl has the advantages that the characteristic that the larger interlayer space of the special three-layer structure of the BiOCl is beneficial to separation of photo-generated electrons and holes is utilized, so that the spectrum absorption range is expanded to a visible light region, the photoresponse capability is greatly improved, and sunlight can be effectively utilized for photocatalytic degradation; the photocatalytic device provided by the invention has a large number of micro-cavity holes, is favorable for adsorbing organic pollutants, and increases TiO2The specific surface area of the/BiOCl composite film photocatalysis layer improves the photocatalysis efficiency and can expandA construction scheme of a photocatalytic reaction device for organic pollutants in water; in addition, the photocatalytic reaction device provided by the invention is easy to separate and recycle from water, and the prepared device solves the problem that the conventional powdery catalyst is difficult to recycle and reuse.
Drawings
FIG. 1 is a view of a photocatalytic device using porous ceramic as a carrier, prepared in example 1 of the present invention; wherein 1 is a porous ceramic carrier, and 2 is TiO2the/BiOCl composite film photocatalysis layer 3 is a microcavity hole.
Detailed Description
The invention provides a photocatalytic device taking porous ceramic as a carrier, which comprises a porous ceramic carrier and TiO positioned on the surface of the porous ceramic carrier and in micro-cavity holes inside the porous ceramic carrier2the/BiOCl composite film photocatalysis layer. The photocatalytic device provided by the invention has the advantages of large specific surface area, wide photoresponse range, extremely strong photocatalytic activity and high catalytic efficiency.
The invention provides a photocatalyst device with porous ceramic as a carrier, which comprises a porous ceramic carrier. The surface and the interior of the porous ceramic carrier are provided with micro-cavity holes. The surface and the internal micro-cavity holes of the porous ceramic carrier are covered with TiO2the/BiOCl composite film photocatalysis layer. In the invention, the volume density of the porous ceramic carrier is preferably 0.5-1.6 g/cm3More preferably 0.8 to 1.4g/cm3(ii) a The pore volume of the porous ceramic carrier is preferably 0.5-1.5 cm/g, and more preferably 0.8-1.5 cm/g; the aperture range of the microcavity holes of the porous ceramic carrier is preferably 150-3500 nm, and more preferably 200-2500 nm.
In the present invention, the porous ceramic support is preferably a cube or a cuboid; the thickness of the porous ceramic carrier is preferably 30-700 μm, and more preferably 60-500 μm.
In the present invention, the method for preparing the porous ceramic support preferably comprises the steps of:
mixing silica gel and water, and carrying out hydrothermal reaction to obtain a porous ceramic carrier;
in the invention, the hardness of the silicone gel is preferably 80-140 g, the viscosity range is preferably 0.01-1.50 mJ, and the drawing length range is preferably 0.58-5.21 mm. In the invention, the mass ratio of the silica gel to the water is preferably (85-95): 5-15, and more preferably 90: 10. The present invention does not require any particular manner of mixing, and may be carried out by methods known to those skilled in the art.
In the invention, the pressure of the hydrothermal reaction is 20-1050 MPa, preferably 100-500 MPa; the temperature of the hydrothermal reaction is 200-500 ℃, and preferably 350-400 ℃; the time of the hydrothermal reaction is 10-240 min, and more preferably 60-120 min. In the hydrothermal reaction process, pores are formed by volatilization of water vapor, and the porous ceramic carrier is obtained.
The photocatalytic device provided by the invention comprises TiO covered on the surface of the porous ceramic carrier and in the internal micro-cavity holes2the/BiOCl composite film photocatalysis layer. In the invention, TiO in the micro-cavity holes on the surface and inside the porous ceramic carrier2The BiOCl mass fraction in the/BiOCl composite film photocatalytic layer is preferably 0.1-6%, and more preferably 1-5%. In the invention, TiO in the micro-cavity holes on the surface and inside the porous ceramic carrier2The thickness of the/BiOCl composite film photocatalytic layer is preferably 50-1000 nm.
In the invention, the photocatalytic device taking the porous ceramic as the carrier has the liquid-phase photocatalytic characteristic and is suitable for catalyzing and degrading organic pollutants in water; the photocatalytic device using the porous ceramic as the carrier is preferably a cuboid.
The invention also provides a preparation method of the photocatalytic device with the porous ceramic as the carrier, which comprises the following steps:
soaking the porous ceramic carrier in a titanium glue solution of flaky BiOCl nano powder to obtain a dipped porous ceramic; micro-cavity holes are formed on the surface and inside of the porous ceramic carrier;
and sintering the impregnated porous ceramic to obtain the photocatalytic device with the porous ceramic as a carrier.
The preparation method provided by the invention has the advantages of simple process, low cost and important application value.
In the present invention, the preparation method of the titanium dioxide solution of BiOCl preferably includes the following steps:
and mixing the flaky BiOCl nano powder with titanium glue to obtain a titanium glue solution of the flaky BiOCl nano powder.
In the invention, the mixing of the flaky BiOCl nano powder and the titanium glue is preferably carried out under the stirring condition, and the stirring speed is preferably 100-400 r/min, and more preferably 300 r/min; the stirring time is preferably 12-36 h, and more preferably 24 h.
In the invention, the particle size of the flaky BiOCl nano powder is preferably 15-900 nm, and more preferably 50-500 nm. In the present invention, the preparation method of the titanium glue preferably comprises the following steps:
mixing glacial acetic acid, water and ethanol to obtain a first solution;
mixing butyl titanate, glacial acetic acid and ethanol to obtain a second solution;
and mixing the first solution and the second solution to obtain the titanium glue.
In the present invention, the water is preferably distilled water; the ethanol is preferably anhydrous ethanol.
In the present invention, the volume ratio of the glacial acetic acid, water and ethanol in the first solution is preferably 3:1: 3. In the present invention, the volume ratio of the butyl titanate, the glacial acetic acid and the ethanol in the second solution is preferably 5:1: 6.
In the invention, the temperature for mixing the first solution and the second solution is preferably 60-110 ℃, and more preferably 90-100 ℃; the mixing is preferably carried out under water bath conditions; the volume ratio of the first solution to the second solution is preferably 1:2 to 1:0.5, and more preferably 1: 1. In the present invention, the method of mixing the first solution and the second solution is preferably: adding the first solution into the second solution under stirring; the stirring speed is preferably 200-400 r/min.
The porous ceramic carrier is soaked in the titanium glue solution of flaky BiOCl nano powder to obtain the impregnated porous ceramic. The invention has no special requirement on the dosage of the titanium glue solution of the flaky BiOCl nano powder, and is suitable for completely immersing the porous ceramic carrier. And drying and sintering the obtained impregnated porous ceramic to obtain the photocatalytic device taking the porous ceramic as a carrier. Preferably, the steps of soaking, drying and sintering are sequentially repeated, so that the surface and the internal micro-cavity holes of the porous ceramic carrier are covered with TiO2the/BiOCl composite film photocatalysis layer. Specifically, the number of times of repeating the steps of soaking, drying and sintering is preferably 2-3 times; the time of each soaking is preferably 5-20 min independently, and more preferably 10-15 min; the temperature of each drying is preferably 50-100 ℃ independently, and more preferably 80-90 ℃; the time for drying each time is preferably 10-40 min independently, and more preferably 20-30 min; the temperature of each sintering is preferably 200-500 ℃, and more preferably 300-400 ℃; the time for each sintering is preferably 2-5 h, and more preferably 3-4 h. In the present invention, the sintering is preferably performed under protective atmosphere conditions, and the gas providing the protective atmosphere preferably includes argon, helium or nitrogen. In the sintering process, the titanium glue solution of the flaky BiOCl nano powder is solidified to form TiO2the/BiOCl composite film photocatalysis layer.
According to the invention, preferably, after the sintering is finished, the obtained sample is naturally cooled to room temperature and then washed, so that the photocatalytic device with the porous ceramic as the carrier is obtained. In the present invention, the detergent for washing is preferably purified water.
In the present invention, TiO2the/BiOCl composite film photocatalytic layer is prepared by a sol-gel method and an extraction method and then is sintered, and has high bonding fastness with a porous ceramic carrier with microcavity holes.
The invention also provides the application of the photocatalytic device with the porous ceramic as the carrier in the technical scheme or the photocatalytic device with the porous ceramic as the carrier prepared by the preparation method in the technical scheme in removing organic pollutants in water. The photocatalytic device provided by the invention has a large number of micro-cavity holes, large specific surface area, strong adsorption capacity and better stability in cyclic use, and is more favorable for improving the degradation efficiency of organic pollutants in wastewater.
In the present invention, the method of application preferably comprises: and mixing the photocatalytic device taking the porous ceramic as the carrier with the wastewater to degrade organic pollutants in the wastewater. In the present invention, the mixing is preferably carried out in a photosensitive reactor, and particularly preferably: and suspending the photocatalytic device taking the porous ceramic as the carrier in a photosensitive reactor, and adding wastewater into the photosensitive reactor to immerse the photocatalytic device taking the porous ceramic as the carrier. In the invention, the mixing is preferably carried out under the condition of stirring, and the stirring speed is preferably 100-300 r/min, and more preferably 150-200 r/min; the stirring time is preferably 10-30 min, and more preferably 20-25 min; the stirring is preferably carried out in a dark condition so that the adsorption and desorption equilibrium is achieved.
In the invention, the catalytic degradation is preferably carried out under 200W-500W xenon lamp irradiation.
In the invention, the photocatalytic device taking porous ceramic as a carrier contacts organic pollutants in water to carry out photocatalytic reaction, and TiO with large specific surface area2O adsorption on surface of/BiOCl composite film2In TiO2Surface capture of photo-generated electrons to generate large amounts of O2-And carrying out oxidation reaction on the rhodamine B to produce carbon dioxide and water. At this time, a large number of holes (h) are generated+) Accumulated in TiO2TiO in/BiOCl composite film2Hydroxyl (-OH) is generated on the interface of the BiOCl and reacts with rhodamine B to produce carbon dioxide and water, so that photoproduction electrons and holes are continuously consumed and effectively separated, and the photocatalysis efficiency is improved.
In a specific embodiment of the present invention, the organic contaminant in the wastewater is preferably rhodamine B; the content of rhodamine B in the wastewater is preferably 5 g/mL.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
Growing a porous ceramic carrier in a reaction kettle by adopting a hydrothermal-hot static pressure method: mixing silica gel and water in a mass ratio of 9:1, setting the pressure of an autoclave at 110MPa, and carrying out hydrothermal reaction at 360 ℃ for 110 min; after the hydrothermal reaction is finished, obtaining a porous ceramic carrier; the obtained porous ceramic carrier has microcavity on its surface and inside, and volume density of 0.9g/cm3(ii) a The pore volume is 1.2 cm/g; the aperture range of the microcavity hole is 200-500 nm; the thickness of the porous ceramic carrier is 200 μm.
Mixing glacial acetic acid, distilled water and absolute ethyl alcohol according to the volume ratio of 3:1:3, and uniformly stirring to form a first solution; uniformly mixing butyl titanate, glacial acetic acid and absolute ethyl alcohol according to the volume ratio of 5:1:6 to form a second solution; slowly adding the first solution into the second solution under stirring in a water bath environment at 95 ℃, wherein the stirring speed is 250r/min, and the stirring time is 12min, so as to obtain titanium glue; weighing 2g of flaky BiOCl nano powder with the particle size range of 100-500 nm, adding the flaky BiOCl nano powder into 100mL of titanium glue, and violently stirring at the rotating speed of 300r/min for 24 hours to obtain a titanium glue solution of the flaky BiOCl nano powder. And soaking the porous ceramic carrier in the titanium glue solution of the flaky BiOCl nano powder for 12min, putting the porous ceramic carrier in a 85 ℃ oven for drying for 25min every time of soaking, sintering the prepared sample in a muffle furnace at 350 ℃ for 3.5h after the soaking and coating are finished, and naturally cooling to room temperature. The soaking-drying-sintering steps are repeated for 2 times; and then soaking and washing with purified water to obtain the photocatalytic device with the porous ceramic as the carrier.
The obtained photocatalytic device using porous ceramic as a carrier is shown in fig. 1. As can be seen from FIG. 1, the photocatalytic device prepared in this example comprises a porous ceramic support, and TiO coated on the surface and in the internal micro-cavity pores of the porous ceramic support2The porous ceramic carrier consists of a/BiOCl composite film photocatalytic layer, wherein micro-cavity holes are formed on the surface and inside the porous ceramic carrier; the surface of the microcavity hole is covered with TiO2the/BiOCl composite film photocatalysis layer.
The photocatalytic device prepared in this example was suspended in a photosensitive reactor, 300 fAdding the rhodamine B wastewater with the concentration of 5g/mL into the photosensitive reactor, stirring for 22min in a dark place, balancing solution adsorption and desorption, and simulating sunlight irradiation (20 KW/m) by using a 300W xenon lamp2) And after 4 hours of illumination, taking out the wastewater, centrifuging, taking out supernatant, testing absorbance by using an ultraviolet spectrophotometer, and calculating the degradation efficiency of the organic pollutants. According to Lambert-beer's law, the absorbance A is proportional to the concentration c of the light-absorbing substance in the low concentration range (dilute solutions with concentrations < 0.01 mol/L), i.e., the concentration ratio is equal to the ratio of absorbance. The calculation formula of the degradation efficiency is as follows: eta is 1-At/A0，A0Initial absorbance of rhodamine B, AtThe absorbance at the time t of light irradiation. The result shows that the spectral absorption range of the device is expanded to a visible light region, and the degradation rate of rhodamine B is 97.5%.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
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