Biochar and photocatalytic material composite coating and drainage pipeline

Abstract

The invention provides a biochar and photocatalytic material composite coating and a drainage pipeline, and belongs to the technical field of water environment treatment and drainage pipelines. The biochar in the composite coating provided by the invention has a rich pore structure and a relatively large specific surface area, and can adsorb pollutants in water, and the photocatalytic material can generate free radicals with strong oxidizing property under an illumination condition, so that the pollutants adsorbed on the surface of the biochar are decomposed into harmless substances such as carbon dioxide and water, and the photocatalytic effect is good. Meanwhile, bacteria and viruses can be killed, and after the surface of the drainage pipeline is coated with the coating, the drainage pipeline has the effects of resisting bacteria and purifying a water body. The result of the embodiment shows that after the inner surface of the drainage pipeline is coated with the biochar and photocatalytic material composite coating, the degradation rate of organic pollutants in sewage is 80% or above, and the total number of bacteria is reduced by 90% or above.

Description

Technical Field

[0001] The present invention belongs to the technical field of water environment treatment and drainage pipes, and particularly relates to a composite coating of biochar and photocatalytic material and a drainage pipe. Background Art

[0002] As urbanization continues to advance, drainage pipes, as a key part of urban infrastructure, are responsible for discharging large quantities of sewage and rainwater. During use, drainage pipes are not only prone to bacterial growth and odor generation, but can also become a secondary source of pollutants, adversely affecting the surrounding water environment. To improve this situation, antibacterial drainage pipes have appeared on the market, coated with antibacterial coatings. However, existing antibacterial drainage pipes can only inhibit bacterial growth to a certain extent and lack effective purification methods for organic pollutants, making it difficult to fundamentally improve water quality. Summary of the Invention

[0003] The present invention aims to provide a biochar and photocatalytic material composite coating and a drainage pipe. When the biochar and photocatalytic material composite coating provided by the present invention is applied to the drainage pipe, it not only has an antibacterial effect but also can degrade organic pollutants.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides a biochar and photocatalytic material composite coating, which comprises the following components by weight: 10-20 parts of biochar, 5-10 parts of photocatalytic material, 2-5 parts of binder and 50-100 parts of water; The particle size of the biochar is 0.1-0.5 mm, and the specific surface area of ​​the biochar is ≥300 m 2 / g; The biochar is obtained by carbonizing agricultural waste; the agricultural waste includes one or more of rice husks, straw, plant branches, plant leaves, peanut shells, sugarcane bagasse, bamboo and coconut shells; The photocatalytic material includes one or more of titanium dioxide, zinc oxide, tin oxide, zirconium dioxide, ferrous oxide, ferric oxide, cobalt oxide, nickel oxide, cuprous oxide and cupric oxide.

[0005] Preferably, the carbonization temperature is 300-700° C., and the carbonization time is 1-3 hours.

[0006] Preferably, the particle size of the photocatalytic material is 10-50 nm.

[0007] Preferably, the binder comprises polyvinyl alcohol and / or sodium silicate.

[0008] Preferably, the number average molecular weight of the polyvinyl alcohol is 8,000-120,000.

[0009] Preferably, the modulus of the sodium silicate is 2.0-3.5.

[0010] The present invention also provides a drainage pipe, comprising a cement drainage pipe and a composite coating coated on the surface of the cement drainage pipe; the composite coating is obtained by curing the biochar and photocatalytic material composite coating described in the above technical solution.

[0011] The present invention provides a biochar and photocatalytic material composite coating, which comprises the following components by weight: 10-20 parts of biochar, 5-10 parts of photocatalytic material, 2-5 parts of binder and 50-100 parts of water. The particle size of the biochar is 0.1-0.5 mm, and the specific surface area of ​​the biochar is ≥300 m 2 / g; the biochar is obtained by carbonizing agricultural waste; the agricultural waste includes one or more of rice husks, straw, plant branches, plant leaves, peanut shells, sugarcane bagasse, bamboo, and coconut shells; the photocatalytic material includes one or more of titanium dioxide, zinc oxide, tin oxide, zirconium dioxide, ferrous oxide, ferric oxide, cobalt oxide, nickel oxide, cuprous oxide, and cupric oxide. The biochar in the composite coating provided by the present invention has a rich pore structure and a large specific surface area, which can absorb pollutants in water. The photocatalytic material can generate strong oxidizing free radicals under light conditions, decomposing pollutants adsorbed on the surface of the biochar into harmless substances such as carbon dioxide and water, while also killing bacteria and viruses. After being applied to the surface of a drainage pipe, the drainage pipe has both antibacterial and water purification functions. The results of the examples show that after the biochar and photocatalytic material composite coating provided by the present invention is applied to the inner surface of a drainage pipe, the degradation rate of organic pollutants in sewage is over 80%, and the total number of bacteria is reduced by over 90%. DETAILED DESCRIPTION

[0012] The invention provides a biochar and photocatalytic material composite coating, which comprises the following components in parts by weight: 10-20 parts of biochar, 5-10 parts of photocatalytic material, 2-5 parts of binder and 50-100 parts of water.

[0013] Unless otherwise specified, the present invention has no particular limitation on the sources of the components, and commercially available products known to those skilled in the art may be used.

[0014] The biochar and photocatalytic material composite coating provided by the present invention includes 10 to 20 parts of biochar by weight. As an embodiment, the weight of the biochar can specifically be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, or 20 parts. The biochar in the composite coating provided by the present invention has a rich pore structure and a large specific surface area, which can adsorb pollutants in water. The present invention controls the amount of biochar within the above range, which can provide more adsorption sites and effectively adsorb pollutants in water.

[0015] In the present invention, the particle size of the biochar is 0.1-0.5 mm; the specific surface area of ​​the biochar is ≥300 m 2 / g. As an embodiment, the specific surface area of ​​the biochar can be specifically 300m 2 / g、320m 2 / g、330m 2 / g、350m 2 / g、360m 2 / g、370m 2 / g、380m 2 / g, 400m 2 / g、410m 2 / g or 420m 2 The present invention controls the particle size and specific surface area of ​​biochar within the above ranges, which can further improve the adsorption performance of pollutants in water bodies.

[0016] In the present invention, the biochar is obtained by carbonizing agricultural waste.

[0017] In the present invention, the agricultural waste includes one or more of rice husks, straws, plant branches, plant leaves, peanut shells, sugarcane bagasse, bamboo and coconut shells.

[0018] The present invention does not particularly limit the specific types of the straw, plant branches, and plant leaves, and any straw, plant branches, and plant leaves known to those skilled in the art can be used. As an embodiment, the straw can be wheat straw, corn straw, or cotton straw; and the plant branches can be willow branches.

[0019] The present invention adopts the above-mentioned agricultural waste. The plant branches are rich in lignin. The biochar obtained by carbonization has a high carbon content and a stable structure, a moderate pH value, can effectively adsorb organic pollutants or heavy metal ions, has a strong synergistic effect with photocatalytic materials, and has a good purification effect; the straw is rich in cellulose and hemicellulose, and can form rich pore structures and active sites after carbonization, with outstanding adsorption performance, and has a good adsorption effect on organic pollutants and heavy metal ions. It can quickly degrade pollutants in combination with photocatalytic materials, has high purification efficiency, and is more suitable for water bodies dominated by organic pollutants; at the same time, the use of agricultural waste is low in cost, wide in source, and economical.

[0020] In the present invention, the agricultural waste is preferably pulverized before carbonization. The present invention has no particular limitation on the pulverization operation, and any pulverization technique known to those skilled in the art can be used.

[0021] In the present invention, the carbonization temperature is preferably 300-700°C; the carbonization time is preferably 1-3 hours; and the rate of heating to the carbonization temperature is preferably 3-10°C / min. As an embodiment, the carbonization temperature may be specifically 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C or 700°C; the carbonization time may be specifically 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours; the rate of heating to the carbonization temperature may be specifically 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min or 10°C / min; and the carbonization is preferably carried out under air, oxygen or nitrogen atmosphere. If the carbonization time is too short or the temperature is too low, the specific surface area and porosity of the biochar will be relatively low, the adsorption capacity will be limited, the adsorption amount of organic pollutants and heavy metal ions will be small, and the purification effect will be poor. The present invention controls the carbonization temperature and time within the above range, which can make the biochar have a larger specific surface area, rich surface functional groups, strong adsorption capacity, stronger synergy with photocatalytic materials, and better water purification effect.

[0022] Based on the weight of biochar being 10 to 20 parts, the biochar and photocatalytic material composite coating provided by the present invention also includes 5 to 10 parts of photocatalytic material. As an embodiment, the weight of the photocatalytic material can specifically be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts. In the present invention, the photocatalytic material can generate strong oxidizing free radicals under light conditions, decomposing pollutants adsorbed on the surface of biochar into harmless substances such as carbon dioxide and water, while also being able to kill bacteria and viruses. After being coated on the surface of the drainage pipe, the drainage pipe has both antibacterial and water purification functions. The present invention controls the amount of photocatalytic material within the above range, which can fully decompose the pollutants adsorbed by biochar.

[0023] In the present invention, the photocatalytic material includes one or more of titanium dioxide, zinc oxide, tin oxide, zirconium dioxide, ferrous oxide, ferric oxide, cobalt oxide, nickel oxide, cuprous oxide and cupric oxide, and more preferably includes two or more of titanium dioxide, zinc oxide, tin oxide, zirconium dioxide, ferrous oxide, ferric oxide, cobalt oxide, nickel oxide, cuprous oxide and cupric oxide. The present invention uses a variety of photocatalytic materials, different photocatalytic materials have different band gaps and photocatalytic properties, and a variety of photocatalytic materials can work synergistically to further improve the decomposition performance of pollutants. For example, when titanium dioxide and zinc oxide are used in combination, titanium dioxide has strong photocatalytic activity in the ultraviolet region, while zinc oxide has a smaller band gap (about 3.37 eV) and also has certain photocatalytic activity in the visible light region. The combination of the two can broaden the spectral response range and improve the utilization rate of light energy. The two can produce a synergistic effect, promote the separation of photogenerated electrons and holes through the formation of a heterojunction, reduce the recombination rate of photogenerated carriers, and enhance the photocatalytic activity. , which can more efficiently degrade various organic pollutants, and its ability to degrade complex organic matter is also significantly enhanced; for example, titanium dioxide, zinc oxide, tin oxide and copper oxide are used in combination. Tin oxide has a moderate band gap width (about 3.6eV). When used in combination with titanium dioxide and zinc oxide, it can further broaden the spectral response range, cover the ultraviolet light region and visible light region, and improve the utilization rate of light energy. The introduction of copper oxide further broadens the spectral response range and enhances the photocatalytic activity. Copper oxide can effectively degrade organic matter and participate in the conversion process of nitrogen and phosphorus, so that the coating has excellent performance in degrading organic matter, removing ammonia nitrogen, total nitrogen and total phosphorus, and the water purification effect is better. As an embodiment, the photocatalytic material may be specifically zinc oxide, or may be specifically titanium dioxide, or may be specifically titanium dioxide and copper oxide in a mass ratio of 2:1, or may be specifically zinc oxide and cuprous oxide in a mass ratio of 4:1, or may be specifically tin oxide and ferric oxide in a mass ratio of 1.5:1, or may be specifically zirconium dioxide and cobalt oxide in a mass ratio of 4:1, or may be specifically nickel oxide and copper oxide in a mass ratio of 7:3, or may be specifically cuprous oxide and ferrous oxide in a mass ratio of 1:1, or may be specifically zinc oxide and copper oxide in a mass ratio of 4:1, or may be specifically titanium dioxide and cuprous oxide in a mass ratio of 7:3.

[0024] In the present invention, the particle size of the photocatalytic material is preferably 10 to 50 nm.

[0025] The biochar and photocatalytic material composite coating provided herein also includes 2 to 5 parts of a binder, based on 10 to 20 parts by weight of biochar. In one embodiment, the binder may be present in 2, 3, 4, or 5 parts by weight. In the present invention, the binder is used to bond the composite coating to the surface of the drainage pipe. By controlling the binder dosage within the aforementioned range, the present invention can further enhance the bond strength between the composite coating and the drainage pipe.

[0026] In the present invention, the binder preferably includes polyvinyl alcohol and / or sodium silicate.

[0027] In the present invention, the number average molecular weight of the polyvinyl alcohol is preferably 8,000 to 120,000; the modulus of the sodium silicate is preferably 2.0 to 3.5. In one embodiment, the modulus of the sodium silicate can be specifically 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, or 3.5.

[0028] The biochar and photocatalytic material composite coating provided by the present invention also includes 50-100 parts by weight of water, based on 10-20 parts by weight of biochar. In one embodiment, the water content can be 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 parts by weight. By controlling the amount of water within the above range, the present invention can fully dissolve or disperse the components to form the composite coating.

[0029] In the present invention, the water is preferably distilled water and / or deionized water.

[0030] The biochar in the composite coating provided by the present invention can adsorb pollutants and heavy metal ions in water. The photocatalytic material generates free radicals with strong oxidizing properties under light conditions, which can decompose pollutants and kill bacteria and viruses at the same time, inhibit the growth of microorganisms in drainage pipes, reduce odor generation, improve water quality, and extend the service life of drainage pipes. The biochar is derived from agricultural waste, realizing the resource utilization of agricultural waste, with a wide source and low cost. The photocatalytic material does not generate harmful substances during use and is pollution-free to the environment, which is in line with the concept of green development.

[0031] The present invention has no particular limitation on the preparation method of the biochar and photocatalytic material composite coating. The components can be uniformly mixed using a preparation method well known to those skilled in the art.

[0032] As an embodiment, the preparation method of the biochar and photocatalytic material composite coating is: adding biochar, photocatalytic material and binder into water, and stirring at 40-60° C. for 10 min-1 h.

[0033] The present invention has no particular limitation on the stirring method and rate. The components may be stirred and mixed uniformly using a stirring technique well known to those skilled in the art.

[0034] The present invention also provides a drainage pipe, comprising a cement drainage pipe and a composite coating coated on the surface of the cement drainage pipe; the composite coating is obtained by curing the biochar and photocatalytic material composite coating described in the above technical solution.

[0035] The present invention does not have any special restrictions on the source and size of the cement drainage pipe. Commercially available cement drainage pipes familiar to those skilled in the art can be used, and the size can be selected according to actual needs. In the present invention, the length of the cement drainage pipe is preferably 15 to 30 meters, and the inner diameter is preferably 0.3 to 0.8 meters. In the present invention, the cement drainage pipe can be obtained by connecting multiple cement drainage pipes end to end in sequence. The present invention does not have any special restrictions on the specific number of the cement drainage pipes, and the length can be selected according to the actual required length. The present invention does not have any special restrictions on the connection method of the multiple cement drainage pipes, and the connection method familiar to those skilled in the art can be used.

[0036] In the present invention, the composite coating can be applied to the inner surface and / or outer surface of the cement drainage pipe.

[0037] In the present invention, the method for preparing the drainage pipe is preferably as follows: coating a composite coating of biochar and photocatalytic material on the surface of a cement drainage pipe, and then curing the coating to obtain the drainage pipe.

[0038] In the present invention, the cement drainage pipe is preferably cleaned and dried before use. The present invention has no special restrictions on the cleaning operation, and a cleaning technique well known to those skilled in the art can be used to ensure that the surface of the cement drainage pipe is clean and free of oil and dust.

[0039] The present invention has no special limitation on the drying operation. A drying technical solution well known to those skilled in the art can be used to ensure that the surface of the cement drainage pipe is free of moisture.

[0040] In the present invention, the coating preferably includes spray coating, brush coating, dipping coating or cloth dipping coating.

[0041] As an embodiment, when spraying or brushing, the thickness of the composite coating is preferably 0.1 to 0.5 mm. The present invention has no particular limitation on the spraying or brushing operation, and a spraying or brushing technique well known to those skilled in the art may be employed to ensure that the thickness of the composite coating is uniform and within the above range.

[0042] In the present invention, the dipping process is preferably performed by completely immersing the cement drainage pipe in the biochar and photocatalytic material composite coating. In the present invention, the dipping process is preferably performed for 25 to 35 minutes, more preferably 30 minutes.

[0043] In the present invention, the fabric dipping coating is preferably performed by dipping the fabric in a composite coating of biochar and photocatalytic material, and then laminating the fabric impregnated with the composite coating on the surface of a cement drainage pipe and pressing the fabric. More preferably, the fabric is dipped in a composite coating of biochar and photocatalytic material, and then laminating the fabric impregnated with the composite coating on the inner surface of a cement drainage pipe and pressing the fabric.

[0044] In the present invention, the fabric is preferably non-woven or woven; the density of the fabric is preferably 30-100 g / m 2 The thickness of the fabric is preferably ≤ 10% of the inner diameter of the cement drainage pipe. The dimensions of the fabric are preferably the same as the inner surface dimensions of the cement drainage pipe. The present invention does not specifically limit the specific material of the fabric; either non-woven or woven fabrics of materials familiar to those skilled in the art may be used. When the dimensions of the fabric differ from the inner surface dimensions of the cement drainage pipe, the present invention preferably cuts the fabric. The present invention does not specifically limit the cutting operation; a cutting technique familiar to those skilled in the art may be used to ensure that the dimensions of the cut fabric are the same as the inner surface dimensions of the cement drainage pipe.

[0045] In the present invention, the immersion temperature is preferably room temperature; the immersion time is preferably 5 to 60 minutes.

[0046] The present invention has no special limitation on the laminating operation. The cloth impregnated with the composite coating can be laminated to the surface of the cement drainage pipe using a technical solution well known to those skilled in the art.

[0047] The present invention does not specifically limit the pressing operation. A pressing method familiar to those skilled in the art can be employed to ensure that the composite coating-impregnated fabric adheres tightly to the surface of the cement drainage pipe and to expel air bubbles. The present invention utilizes a fabric dip coating to further enhance the bonding strength with the cement drainage pipe, making the composite coating more secure and less susceptible to detachment, thereby increasing the service life and reliability of the drainage pipe.

[0048] In the present invention, the curing is preferably carried out by air-drying or drying; the drying temperature is preferably 40-60° C.; and the drying time is preferably 2-4 hours.

[0049] The drainage pipe provided by the present invention has antibacterial and water purification functions.

[0050] The preparation method of the drainage pipe of the present invention is simple and easy, the coating method is flexible and diverse, and can be adjusted according to the specifications and shapes of different cement drainage pipes, and has good adaptability.

[0051] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0052] Example 1 A biochar and photocatalytic material composite coating, comprising, by weight, 15 parts of biochar, 7.5 parts of a photocatalytic material (titanium dioxide, 20-30 nm), 3.5 parts of a binder (polyvinyl alcohol, number average molecular weight 40,000), and 75 parts of deionized water; The biochar preparation method is as follows: placing rice husks in a tube furnace, heating to 500°C at 5°C / min under a nitrogen atmosphere for 2 hours, and cooling to obtain biochar; the specific surface area of ​​the biochar is 350m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 50° C. for 30 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0053] Application Example 1 A drainage pipe comprising a cement drainage pipe (20 m in length and 0.3 m in inner diameter) and a composite coating applied to the inner surface of the cement drainage pipe, wherein the composite coating is obtained by curing the biochar and photocatalytic material composite coating of Example 1; The preparation method of the drainage pipe is as follows: the cement drainage pipe is cleaned and dried in sequence, and then the biochar and photocatalytic material composite coating in Example 1 is sprayed onto the inner surface of the cement drainage pipe. After the spraying is completed, the composite coating is dried at 50° C. for 3 hours to obtain the drainage pipe. The thickness of the composite coating is 0.5 mm.

[0054] Prepare simulated sewage (COD is 70 mg / L), and then continuously pass the simulated sewage from the inside of the drainage pipe through the drainage pipe in Application Example 1 under outdoor natural sunlight conditions at a flow rate of 0.3 m / s. Then, according to the "Water Quality - Determination of Chemical Oxygen Demand - Dichromate Method" (GB / T 11914-1989), the COD in the simulated sewage before and after passing through the drainage pipe was tested, and the pollutant degradation rate was calculated to be 85%.

[0055] Water samples were collected at the outlet of the drainage pipe and inoculated on nutrient agar plates together with simulated sewage. The samples were cultured for 48 hours and then counted. The results showed that the total number of bacteria decreased by 92% after passing through the drainage pipe.

[0056] Example 2 A biochar and photocatalytic material composite coating, comprising, by weight, 20 parts of biochar, 10 parts of photocatalytic material (zinc oxide, 20-30 nm), 5 parts of binder (sodium silicate, modulus 3.0), and 100 parts of deionized water; The biochar preparation method comprises the following steps: crushing wheat straw and placing it in a tube furnace, heating it to 600°C at a rate of 10°C / min in an air atmosphere, carbonizing it for 1.5 hours, and cooling it to obtain biochar; the specific surface area of ​​the biochar is 400m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 40° C. for 40 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0057] Application Example 2 A drainage pipe comprising a cement drainage pipe (15 m in length and 0.5 m in inner diameter) and a composite coating applied to the inner surface of the cement drainage pipe, wherein the composite coating is obtained by curing the biochar and photocatalytic material composite coating of Example 2; The preparation method of the drainage pipe is as follows: (1) cleaning and drying the cement drainage pipe in sequence; (2) Woven glass fiber cloth (thickness 0.5mm, density 80g / m 2 ) was cut into the same size as the inner surface of the cement drainage pipe, and then immersed in the biochar and photocatalytic material composite coating of Example 2 for 30 minutes. Then, the glass fiber woven cloth impregnated with the composite coating was attached to the inner surface of the cement drainage pipe, pressed with a rubber roller to expel bubbles, and dried at 50°C for 3 hours to obtain a drainage pipe.

[0058] According to the same test method as in Application Example 1, the degradation rate of pollutants in the drainage pipe in Application Example 2 was 88%, and the total number of bacteria was reduced by 94%.

[0059] Example 3 A biochar and photocatalytic material composite coating, comprising, by weight, 10 parts of biochar, 7.5 parts of a photocatalytic material (5 parts of titanium dioxide, 2.5 parts of copper oxide, with the particle sizes of titanium dioxide and copper oxide being 20-30 nm, respectively), 3 parts of a binder (polyvinyl alcohol and sodium silicate in a mass ratio of 1:1, with the number average molecular weight of the polyvinyl alcohol being 50,000 and the modulus of the sodium silicate being 2.0), and 50 parts of deionized water; The biochar preparation method comprises the following steps: crushing corn stalks and placing them in a tube furnace; heating them to 300°C at a rate of 5°C / min under a nitrogen atmosphere for carbonization for 3 hours; and cooling them to obtain biochar; the specific surface area of ​​the biochar is 300m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 60° C. for 20 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0060] Application Example 3 A drainage pipe comprising a cement drainage pipe (20 m in length and 0.8 m in inner diameter) and a composite coating applied to the inner surface of the cement drainage pipe, wherein the composite coating is obtained by curing the biochar and photocatalytic material composite coating of Example 3; The preparation method of the drainage pipe is as follows: (1) cleaning and drying the cement drainage pipe in sequence; (2) Polypropylene non-woven fabric (thickness 0.4mm, density 50g / m 2 ) was cut into the same size as the inner surface of the cement drainage pipe, and then immersed in the biochar and photocatalytic material composite coating of Example 3 for 30 minutes. Then, the polypropylene non-woven fabric impregnated with the composite coating was attached to the inner surface of the cement drainage pipe, pressed with a rubber roller to expel bubbles, and dried at 50°C for 3 hours to obtain a drainage pipe.

[0061] According to the same test method as in Application Example 1, the degradation rate of pollutants in the drainage pipe in Application Example 3 was 82%, and the total number of bacteria was reduced by 90%.

[0062] Example 4 A biochar and photocatalytic material composite coating, comprising, by weight, 18 parts of biochar, 10 parts of photocatalytic material (8 parts of zinc oxide, 2 parts of cuprous oxide, with the particle sizes of zinc oxide and cuprous oxide being 10-20 nm, respectively), 4 parts of a binder (polyvinyl alcohol, with a number average molecular weight of 40,000), and 60 parts of deionized water; The biochar preparation method comprises the following steps: crushing willow branches and placing them in a tube furnace, heating them to 400°C at a rate of 5°C / min in an oxygen atmosphere, carbonizing them for 2.5 hours, and cooling them to obtain biochar; the specific surface area of ​​the biochar is 380 m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 45° C. for 35 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0063] Application Example 4 A drainage pipe comprising a cement drainage pipe (20 m in length and 0.5 m in inner diameter) and a composite coating applied to the inner surface of the cement drainage pipe, wherein the composite coating is obtained by curing the biochar and photocatalytic material composite coating of Example 4; The preparation method of the drainage pipe is as follows: (1) cleaning and drying the cement drainage pipe in sequence; (2) Aramid woven fabric (thickness 0.6mm, density 100g / m 2 ) was cut into the same size as the inner surface of the cement drainage pipe, and then immersed in the biochar and photocatalytic material composite coating of Example 4 for 30 minutes. Then, the aramid woven fabric impregnated with the composite coating was attached to the inner surface of the cement drainage pipe, pressed with a rubber roller to expel bubbles, and dried at 55°C for 3.5 hours to obtain a drainage pipe.

[0064] According to the same test method as in Application Example 1, the degradation rate of pollutants in the drainage pipe in Application Example 4 was 90%, and the total number of bacteria was reduced by 95%.

[0065] Example 5 A biochar and photocatalytic material composite coating, comprising, by weight, 12 parts of biochar, 10 parts of photocatalytic material (6 parts of tin oxide, 4 parts of ferric oxide, with particle sizes of tin oxide and ferric oxide of 10-20 nm, respectively), 3 parts of a binder (sodium silicate, modulus 2.5), and 60 parts of deionized water; The biochar preparation method comprises the following steps: crushing peanut shells and placing them in a tube furnace, heating them to 550°C at 8°C / min under a nitrogen atmosphere, carbonizing them for 2 hours, and cooling them to obtain biochar; the specific surface area of ​​the biochar is 420 m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 55° C. for 25 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0066] Application Example 5 A drainage pipe comprising a cement drainage pipe (15 m in length and 0.6 m in inner diameter) and a composite coating applied to the inner surface of the cement drainage pipe, the composite coating being obtained by curing the biochar and photocatalytic material composite coating of Example 5; The preparation method of the drainage pipe is as follows: (1) cleaning and drying the cement drainage pipe in sequence; (2) Polyester non-woven fabric (thickness 0.3mm, density 65g / m 2) was cut into the same size as the inner surface of the cement drainage pipe, and then immersed in the biochar and photocatalytic material composite coating of Example 5 for 30 minutes. Then, the polyester non-woven fabric impregnated with the composite coating was attached to the inner surface of the cement drainage pipe, pressed with a rubber roller to expel bubbles, and dried at 45°C for 3.5 hours to obtain a drainage pipe.

[0067] According to the same test method as in Application Example 1, the degradation rate of pollutants in the drainage pipe in Application Example 5 was 87%, and the total number of bacteria was reduced by 93%.

[0068] Example 6 A biochar and photocatalytic material composite coating, comprising, by weight, 16 parts of biochar, 10 parts of a photocatalytic material (8 parts of zirconium dioxide, 2 parts of cobalt oxide, with particle sizes of zirconium dioxide and cobalt oxide of 10 to 20 nm, respectively), 3.5 parts of a binder (polyvinyl alcohol and sodium silicate in a mass ratio of 1:1, with a number average molecular weight of the polyvinyl alcohol of 50,000 and a modulus of the sodium silicate of 2.5), and 70 parts of deionized water; The biochar preparation method comprises the following steps: crushing cotton straw and placing it in a tube furnace, heating it to 350°C at 5°C / min under a nitrogen atmosphere, carbonizing it for 2.5 hours, and cooling it to obtain biochar; the specific surface area of ​​the biochar is 320 m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 45° C. for 30 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0069] Application Example 6 A drainage pipe comprising a cement drainage pipe (15 m in length and 0.5 m in inner diameter) and a composite coating applied to the inner surface of the cement drainage pipe, wherein the composite coating is obtained by curing the biochar and photocatalytic material composite coating of Example 6; The preparation method of the drainage pipe is as follows: (1) cleaning and drying the cement drainage pipe in sequence; (2) Polypropylene non-woven fabric (thickness 0.2mm, density 50g / m 2 ) was cut into the same size as the inner surface of the cement drainage pipe, and then immersed in the biochar and photocatalytic material composite coating of Example 6 for 30 minutes. Then, the polyester non-woven fabric impregnated with the composite coating was attached to the inner surface of the cement drainage pipe, pressed with a rubber roller to expel bubbles, and dried at 50°C for 3 hours to obtain a drainage pipe.

[0070] According to the same test method as in Application Example 1, the degradation rate of pollutants in the drainage pipe in Application Example 6 was 89%, and the total number of bacteria was reduced by 94%.

[0071] Example 7 A biochar and photocatalytic material composite coating, comprising, by weight, 14 parts of biochar, 10 parts of photocatalytic material (7 parts of nickel trioxide, 3 parts of copper oxide, with the particle sizes of nickel trioxide and copper oxide being 20-30 nm, respectively), 4 parts of a binder (polyvinyl alcohol, with a number average molecular weight of 40,000), and 80 parts of deionized water; The biochar preparation method comprises the following steps: crushing coconut shells and placing them in a tube furnace, heating them to 450°C at a rate of 6°C / min in an oxygen atmosphere, carbonizing them for 2 hours, and cooling them to obtain biochar; the specific surface area of ​​the biochar is 360 m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 50° C. for 35 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0072] Application Example 7 A drainage pipe comprising a cement drainage pipe (30 m in length and 0.8 m in inner diameter) and a composite coating applied to the inner surface of the cement drainage pipe, the composite coating being obtained by curing the biochar and photocatalytic material composite coating of Example 7; The preparation method of the drainage pipe is as follows: (1) cleaning and drying the cement drainage pipe in sequence; (2) The biochar and photocatalytic material composite coating of Example 7 was sprayed on a cement drainage pipe and dried at 60° C. for 2 h to obtain a drainage pipe. The thickness of the composite coating was 0.5 mm.

[0073] According to the same test method as in Application Example 1, the degradation rate of pollutants in the drainage pipe in Application Example 7 was 91%, and the total number of bacteria was reduced by 96%.

[0074] Example 8 A biochar and photocatalytic material composite coating, comprising, by weight, 10 parts of biochar, 10 parts of photocatalytic material (5 parts of cuprous oxide, 5 parts of ferrous oxide, with particle sizes of cuprous oxide and ferrous oxide being 10-20 nm, respectively), 2 parts of a binder (sodium silicate, with a modulus of 3.5), and 50 parts of deionized water; The biochar preparation method comprises the following steps: crushing sugarcane bagasse and placing it in a tube furnace, heating it to 400°C at a rate of 5°C / min under a nitrogen atmosphere, carbonizing it for 3 hours, and cooling it to obtain biochar; the specific surface area of ​​the biochar is 330 m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 40° C. for 40 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0075] Application Example 8 A drainage pipe comprising a cement drainage pipe (20 m in length and 0.5 m in inner diameter) and a composite coating applied to the inner surface of the cement drainage pipe, wherein the composite coating is obtained by curing the biochar and photocatalytic material composite coating of Example 8; The preparation method of the drainage pipe is as follows: (1) cleaning and drying the cement drainage pipe in sequence; (2) The biochar and photocatalytic material composite coating of Example 8 was brush-coated on a cement drainage pipe and naturally dried in a ventilated and dry place for 8 hours to obtain a drainage pipe. The thickness of the composite coating was 0.5 mm.

[0076] According to the same test method as in Application Example 1, the degradation rate of pollutants in the drainage pipe in Application Example 8 was 86%, and the total number of bacteria was reduced by 95%.

[0077] Example 9 A biochar and photocatalytic material composite coating, comprising, by weight, 16 parts of biochar, 10 parts of photocatalytic material (8 parts of zinc oxide, 2 parts of copper oxide, with the particle sizes of copper oxide and zinc oxide being 20-30 nm, respectively), 3.5 parts of a binder (polyvinyl alcohol, with a number average molecular weight of 40,000), and 70 parts of deionized water; The biochar preparation method comprises the following steps: crushing bamboo and placing it in a tube furnace, heating it to 550°C at 5°C / min under a nitrogen atmosphere, carbonizing it for 2 hours, and cooling it to obtain biochar; the specific surface area of ​​the biochar is 410 m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 45° C. for 30 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0078] Application Example 9 A drainage pipe comprising a cement drainage pipe (15 m in length and 0.4 m in inner diameter) and a composite coating applied to the inner surface of the cement drainage pipe, the composite coating being obtained by curing the biochar and photocatalytic material composite coating of Example 9; The preparation method of the drainage pipe is as follows: (1) cleaning and drying the cement drainage pipe in sequence; (2) Glass fiber non-woven fabric (thickness 0.3mm, density 55g / m 2) was cut into the same size as the inner surface of the cement drainage pipe, and then immersed in the biochar and photocatalytic material composite coating of Example 9 for 30 minutes. Then, the glass fiber non-woven fabric impregnated with the composite coating was attached to the inner surface of the cement drainage pipe, pressed with a rubber roller to expel bubbles, and dried at 50°C for 3 hours to obtain a drainage pipe.

[0079] According to the same test method as in Application Example 1, the degradation rate of pollutants in the drainage pipe in Application Example 9 was 90%, and the total number of bacteria was reduced by 95%.

[0080] Example 10 A biochar and photocatalytic material composite coating, comprising, by weight, 14 parts of biochar, 10 parts of a photocatalytic material (7 parts of titanium dioxide, 3 parts of cuprous oxide, with the particle sizes of titanium dioxide and cuprous oxide being 10-20 nm, respectively), 3 parts of a binder (polyvinyl alcohol and sodium silicate in a mass ratio of 1:1, with the number average molecular weight of the polyvinyl alcohol being 40,000 and the modulus of the sodium silicate being 2.5), and 60 parts of deionized water; The biochar preparation method comprises the following steps: crushing coconut shells and placing them in a tube furnace, heating them to 350°C at a rate of 4°C / min under a nitrogen atmosphere, carbonizing them for 2.5 hours, and cooling them to obtain biochar; the specific surface area of ​​the biochar is 370 m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 50° C. for 25 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0081] Application Example 10 A drainage pipe comprising a cement drainage pipe (20 m in length and 0.5 m in inner diameter) and a composite coating applied to the inner surface of the cement drainage pipe, the composite coating being obtained by curing the biochar and photocatalytic material composite coating of Example 10; The preparation method of the drainage pipe is as follows: (1) cleaning and drying the cement drainage pipe in sequence; (2) Polyester non-woven fabric (thickness 0.3mm, density 65g / m 2 ) was cut into the same size as the inner surface of the cement drainage pipe, and then immersed in the biochar and photocatalytic material composite coating of Example 10 for 30 minutes. Then, the polyester non-woven fabric impregnated with the composite coating was attached to the inner surface of the cement drainage pipe, pressed with a rubber roller to expel bubbles, and dried at 50°C for 3 hours to obtain a drainage pipe.

[0082] According to the same test method as in Application Example 1, the degradation rate of pollutants in the drainage pipe in Application Example 10 was 91%, and the total number of bacteria was reduced by 96%.

[0083] Example 11 A biochar and photocatalytic material composite coating, comprising, by weight, 12 parts of biochar, 10 parts of photocatalytic material (6 parts of tin oxide, 4 parts of ferric oxide, with particle sizes of tin oxide and ferric oxide of 10-20 nm, respectively), 3 parts of a binder (sodium silicate, modulus 2.5), and 60 parts of deionized water; The biochar preparation method comprises the following steps: crushing peanut shells and placing them in a tube furnace, heating them to 550°C at 8°C / min under a nitrogen atmosphere, carbonizing them for 2 hours, and cooling them to obtain biochar; the specific surface area of ​​the biochar is 420 m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 55° C. for 25 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0084] Application Example 11 A drainage pipe comprising a cement drainage pipe (20 m in length and 0.6 m in inner diameter) and a composite coating applied to the surface of the cement drainage pipe, wherein the composite coating is obtained by curing the biochar and photocatalytic material composite coating of Example 11; The preparation method of the drainage pipe is as follows: the cement drainage pipe is cleaned and dried in sequence, and then the cement drainage pipe is completely immersed in a container containing the biochar and photocatalytic material composite coating of Example 11 for 30 minutes, and then the cement drainage pipe is lifted up to allow excess composite coating to flow back into the container, and then dried at 45° C. for 3.5 hours to obtain the drainage pipe.

[0085] According to the same test method as in Application Example 1, the degradation rate of pollutants in the drainage pipe in Application Example 11 was 87%, and the total number of bacteria was reduced by 93%.

[0086] Example 12 A biochar and photocatalytic material composite coating, comprising, by weight, 16 parts of biochar, 10 parts of photocatalytic material (8 parts of zinc oxide, 2 parts of copper oxide, with the particle sizes of zinc oxide and copper oxide being 20-30 nm, respectively), 3.5 parts of a binder (polyvinyl alcohol, with a number average molecular weight of 30,000), and 70 parts of deionized water; The biochar preparation method comprises the following steps: crushing bamboo and placing it in a tube furnace, heating it to 550°C at 5°C / min under a nitrogen atmosphere, carbonizing it for 2 hours, and cooling it to obtain biochar; the specific surface area of ​​the biochar is 410 m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 45° C. for 30 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0087] Application Example 12 A drainage pipe comprising a cement drainage pipe (16 m in length and 0.5 m in inner diameter) and a composite coating applied to the surface of the cement drainage pipe, wherein the composite coating is obtained by curing the biochar and photocatalytic material composite coating of Example 12; The preparation method of the drainage pipe is as follows: the cement drainage pipe is cleaned and dried in sequence, and then the cement drainage pipe is completely immersed in a container containing the biochar and photocatalytic material composite coating of Example 12 for 25 minutes, and then the cement drainage pipe is lifted to allow excess composite coating to flow back into the container, and then dried at 55° C. for 3 hours to obtain the drainage pipe.

[0088] According to the same test method as in Application Example 1, the degradation rate of pollutants in the drainage pipe in Application Example 12 was 90%, and the total number of bacteria was reduced by 95%.

[0089] Example 13 A biochar and photocatalytic material composite coating, comprising, by weight, 14 parts of biochar, 10 parts of a photocatalytic material (7 parts of titanium dioxide, 3 parts of cuprous oxide, with the particle sizes of titanium dioxide and cuprous oxide being 10-20 nm, respectively), 3 parts of a binder (polyvinyl alcohol and sodium silicate in a mass ratio of 1:1, with the number average molecular weight of the polyvinyl alcohol being 30,000 and the modulus of the sodium silicate being 3.0), and 60 parts of deionized water; The biochar preparation method comprises the following steps: crushing coconut shells and placing them in a tube furnace, heating them to 350°C at a rate of 5°C / min under a nitrogen atmosphere, carbonizing them for 2.5 hours, and cooling them to obtain biochar; the specific surface area of ​​the biochar is 370 m 2 / g, particle size is 0.1~0.5mm; The preparation method of the biochar and photocatalytic material composite coating comprises the following steps: adding biochar, photocatalytic material and binder into deionized water, stirring at 50° C. for 25 minutes, and obtaining the biochar and photocatalytic material composite coating.

[0090] Application Example 13 A drainage pipe comprising a cement drainage pipe (20 m in length and 0.4 m in inner diameter) and a composite coating applied to the surface of the cement drainage pipe, wherein the composite coating is obtained by curing the biochar and photocatalytic material composite coating of Example 13; The preparation method of the drainage pipe is as follows: the cement drainage pipe is cleaned and dried in sequence, and then the cement drainage pipe is completely immersed in a container containing the biochar and photocatalytic material composite coating of Example 13 for 30 minutes, and then the cement drainage pipe is lifted to allow the excess composite coating to flow back into the container, and then dried at 50°C for 3.5 hours to obtain the drainage pipe.

[0091] According to the same test method as in Application Example 1, the degradation rate of pollutants in the drainage pipe in Application Example 13 was 91%, and the total number of bacteria was reduced by 96%.

[0092] In summary, the biochar and photocatalytic material composite coating provided by the present invention is applied to the surface of the cement drainage pipe to obtain a drainage pipe with a degradation rate of more than 80% for organic pollutants in water and a reduction of more than 90% in the total number of bacteria, showing good water environment purification effect and antibacterial and antibacterial properties, and has broad application prospects.

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A biochar and photocatalytic material composite coating, characterized in that: The composition comprises the following components by weight: 10-20 parts of biochar, 5-10 parts of photocatalytic material, 2-5 parts of binder and 50-100 parts of water; The particle size of the biochar is 0.1-0.5 mm, and the specific surface area of ​​the biochar is ≥300 m 2 / g; The biochar is obtained by carbonizing agricultural waste; the agricultural waste includes one or more of rice husks, straw, plant branches, plant leaves, peanut shells, sugarcane bagasse, bamboo and coconut shells; The photocatalytic material includes one or more of titanium dioxide, zinc oxide, tin oxide, zirconium dioxide, ferrous oxide, ferric oxide, cobalt oxide, nickel oxide, cuprous oxide and cupric oxide.

2. The biochar and photocatalytic material composite coating according to claim 1, characterized in that: The carbonization temperature is 300-700° C., and the carbonization time is 1-3 hours.

3. The biochar and photocatalytic material composite coating according to claim 1, characterized in that: The particle size of the photocatalytic material is 10-50 nm.

4. The biochar and photocatalytic material composite coating according to claim 1, characterized in that: The binder includes polyvinyl alcohol and / or sodium silicate.

5. The biochar and photocatalytic material composite coating according to claim 4, characterized in that: The number average molecular weight of the polyvinyl alcohol is 8,000-120,000.

6. The biochar and photocatalytic material composite coating according to claim 4, characterized in that: The modulus of the sodium silicate is 2.0-3.

5.

7. A drainage pipe comprising a cement drainage pipe and a composite coating applied to the surface of the cement drainage pipe; the composite coating is obtained by curing the biochar and photocatalytic material composite coating according to any one of claims 1 to 6.