Bamboo activated carbon and preparation method thereof

Abstract

The invention relates to the technical field of biomass activated carbon, in particular to bamboo activated carbon and a preparation method thereof. The bamboo activated carbon is bamboo activated carbon raw powder of which the surface is loaded with N-doped titanium dioxide, and the N-doped titanium dioxide is added in a gel form. The bamboo activated carbon provided by the invention has a more excellent adsorption treatment effect on ammonia gas.

Description

Technical Field

[0001] The present application relates to the technical field of biomass activated carbon, and more specifically, to bamboo activated carbon and a preparation method thereof. Background Art

[0002] Activated carbon is a type of porous material that is crushed into blocks from coal or biomass materials and prepared through carbonization and activation. It is widely used in the field of gas and liquid adsorption purification because of its certain strength, high specific surface area, good thermal stability, rich pore structure and reusability.

[0003] Biomass activated carbon is a type of activated carbon prepared from industrial or agricultural waste as raw materials. Therefore, it can effectively reduce the pollution of industrial or agricultural waste to the environment, and at the same time realize the secondary utilization of waste resources. At the same time, biomass activated carbon also has similar properties to coal-based activated carbon. In addition, with the depletion of fossil fuels, the rising cost of coal and the intensification of the greenhouse effect, coal-based activated carbon is gradually being replaced by biomass activated carbon.

[0004] Bamboo is a widely available, fast-growing, renewable biomass material, but the utilization rate of bamboo resources is not sufficient. Bamboo activated carbon can make use of discarded bamboo, thereby further expanding the utilization rate of bamboo resources. However, bamboo activated carbon mostly adsorbs harmful gases, and the harmful gases are not actually effectively treated. After long-term use of bamboo activated carbon, as the amount of harmful gases adsorbed increases, the adsorption effect of bamboo activated carbon on harmful gases will gradually deteriorate. Therefore, there is an urgent need for a bamboo activated carbon that can adsorb and treat harmful gases. Summary of the invention

[0005] In order to improve the defect that conventional bamboo activated carbon is difficult to effectively treat harmful gases, the present application provides a bamboo activated carbon and a preparation method thereof.

[0006] In the first aspect, the present application provides a bamboo activated carbon, which adopts the following technical solution: The invention discloses bamboo activated carbon, which is raw bamboo activated carbon powder with N-doped titanium dioxide loaded on the surface, and the N-doped titanium dioxide is added in the form of gel.

[0007] When titanium dioxide is loaded on bamboo activated carbon, since titanium dioxide has a certain photocatalytic effect, when it is exposed to light, the electrons in titanium dioxide will cross the forbidden band from the valence band and then jump to the conduction band, thereby generating corresponding holes in the valence band. These photogenerated electrons and holes with redox activity convert oxygen and water molecules into highly oxidizing ·O2 and ·OH, respectively, thereby quickly reacting the ammonia adsorbed on the bamboo activated carbon to generate NO, NO2 or N2, thereby achieving the effect of purifying ammonia.

[0008] However, since the place where ammonia is treated is basically an indoor environment such as a bathroom, and the light in the indoor environment is mainly reflected light and scattered light, the lighting effect is not good, which leads to insufficient photocatalytic effect of titanium dioxide. When titanium dioxide is loaded with N, N can cause more defects in titanium dioxide. At the same time, nitrogen can also replace oxygen to form nitrogen oxide in the form of bonds, so that titanium dioxide can capture more charge carriers and inhibit the recombination of electrons and holes, thereby enhancing the photocatalytic effect of titanium dioxide.

[0009] Preferably, the preparation method of the N-doped titanium dioxide gel is: first, 10 g of titanium tetrachloride is added dropwise to 100 g of deionized water, and after the solution becomes clear and transparent, ammonia water is slowly added dropwise until the pH value of the solution is neutral, to obtain the N-doped titanium dioxide gel.

[0010] Preferably, the raw bamboo activated carbon powder is subjected to microporation treatment.

[0011] Preferably, the microporation treatment comprises the following steps: Preparation of raw material powder: crush and grind the bamboo raw material, and sieve to obtain 60-80 mesh bamboo raw material powder; Primary deashing: The bamboo raw material powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 30-50°C for 50-70 minutes, then washed with deionized water at 30-50°C until neutral and dried to obtain primary deashing powder; Primary carbonization: placing the primary deashing powder in an argon protective atmosphere, heating it to 400-600°C at a rate of 7-8°C / min, then carbonizing it for 100-120min, and finally cooling it to room temperature to obtain primary carbonized powder; Secondary carbonization: the primary carbonized powder is mixed with sodium hydroxide in a mass ratio of 5:1, then placed in an argon protective atmosphere, heated to 900-1200°C at a rate of 5-10°C / min, then carbonized for 50-70min, and finally cooled to room temperature to obtain secondary carbonized powder; Secondary deashing: The secondary carbonized powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 30-50°C for 50-70 min, then washed with deionized water and water at 30-50°C until neutral and dried to obtain secondary deashed powder; Activation: Place the secondary deashing powder in a steam activation device and activate it at 700-900℃ for 2-4h to obtain the raw bamboo activated carbon powder.

[0012] Although loading N-doped titanium dioxide on bamboo activated carbon can give bamboo activated carbon the function of purifying ammonia, N-doped titanium dioxide is usually loaded on the micropores of bamboo activated carbon, and the reduction of micropores will significantly reduce the adsorption of ammonia by bamboo activated carbon.

[0013] In the microporation treatment, the raw materials are deashed multiple times through acid washing and deionized water treatment, and the alkalinity fully removes the impurity elements in the raw materials, so as to further form pores in the subsequent activation process, thereby compensating for the problem of decreased adsorption after bamboo activated carbon is loaded with N-doped titanium dioxide.

[0014] Preferably, the microporation treatment comprises the following steps: Preparation of raw material powder: crush and grind the bamboo raw material, and sieve to obtain 60-80 mesh bamboo raw material powder; Primary deashing: The bamboo raw material powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 30-50°C for 50-70 minutes, then washed with deionized water at 30-50°C until neutral and dried to obtain primary deashing powder; Primary carbonization: placing the primary deashing powder in an argon protective atmosphere, heating it to 400-600°C at a rate of 7-8°C / min, then carbonizing it for 100-120min, and finally cooling it to room temperature to obtain primary carbonized powder; Organic solvent attachment: soak the primary carbonized powder in o-xylene solvent at a ratio of 1g:10ml for 1-3h, and then dry it to obtain the pre-treated powder; Secondary carbonization: The pretreated powder is mixed with sodium hydroxide in a mass ratio of 5:1, and then placed in an argon protective atmosphere, heated to 900-1200°C at a rate of 5-10°C / min, and then carbonized for 50-70 minutes, and finally cooled to room temperature to obtain secondary carbonized powder; Carbon black separation: Place the secondary carbonized powder in ethanol at a ratio of 1g:10ml, heat it to 180-220℃ at a rate of 4-6℃ / min, and evaporate and stir at a stirring speed of 400-600r / min to obtain post-treated secondary carbonized powder; Secondary deashing: the post-treated secondary carbonized powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 30-50°C for 50-70 min, then washed with deionized water and water at 30-50°C until neutral and dried to obtain secondary deashed powder; Activation: Place the secondary deashing powder in a steam activation device and activate it at 700-900℃ for 2-4h to obtain the raw bamboo activated carbon powder.

[0015] In the microporation treatment, an organic solvent is first attached after the primary carbonization, and then the organic solvent is cracked under high temperature to produce carbon black, which is then removed with ethanol to obtain more micropores, further improving the adsorption performance of bamboo activated carbon.

[0016] Preferably, after the surface of the raw bamboo activated carbon powder is loaded with N-doped titanium dioxide, it is also modified with citric acid.

[0017] Preferably, the citric acid modification step is: first, the raw powder of bamboo activated carbon loaded with N-doped titanium dioxide is placed in an environment of 100-120°C for drying, then immersed in a 50-70% citric acid aqueous solution at a ratio of 1g:2ml, shaken and immersed at a temperature of 20-40°C for 40-50h, and finally filtered and dried to obtain bamboo activated carbon.

[0018] Ammonia, as an alkaline gas, can combine with acidic sites. Therefore, constructing acidic sites on the surface of bamboo activated carbon can further enhance the adsorption effect of bamboo activated carbon on ammonia. As the number and strength of acidic sites increase, the adsorption effect becomes stronger.

[0019] Generally speaking, there are two main ways for ammonia to combine with acidic sites. One is that the metal cation of the metal oxide accepts the lone pair of electrons of the nitrogen atom and acts as a Lewis acid site on the surface. The other is that ammonia is protonated by the surface oxygen-containing functional groups or water protons, and then adsorbed on the surface through acid-base interactions with Brønsted acid sites. Therefore, constructing oxygen-containing functional groups on the surface of bamboo activated carbon can further enhance the adsorption effect of bamboo activated carbon on ammonia.

[0020] Organic acid modification can promote the formation of a large number of carboxyl functional groups on the surface of bamboo activated carbon, and the carboxyl functional groups can react chemically with ammonia to achieve the effect of adsorbing ammonia. The types of organic acids include citric acid, acetic acid, etc., but because the molecular formula of citric acid contains three carboxyl groups, the carboxyl content per mol of citric acid is higher, so compared with acetic acid modification, citric acid-modified bamboo activated carbon has a better ammonia adsorption effect.

[0021] In a second aspect, the present application provides a method for preparing bamboo activated carbon, which adopts the following technical scheme: A method for preparing bamboo activated carbon comprises the following steps: Preparation of N-doped titanium dioxide gel: First, 10 g of titanium tetrachloride was added dropwise to 100 g of deionized water. After the solution became clear and transparent, ammonia was slowly added dropwise until the pH value of the solution was neutral. Finally, 20 g of N-doped titanium dioxide gel was obtained by concentration. Preparation of activated carbon solution: Add 0.12 g thiourea and 0.2 g bamboo activated carbon powder into 100 ml deionized water, mix and stir evenly, then slowly add hydrochloric acid until the pH value of the mixture is 2.5 to obtain an activated carbon solution; Preparation of bamboo activated carbon: N-doped titanium dioxide gel was added dropwise to the activated carbon solution for mixing at a mixing temperature of 75°C for 24 hours, followed by drying at 100-120°C for 6-18 hours, and then calcining at 300-400°C for 2-4 hours, and finally grinding to obtain bamboo activated carbon.

[0022] A method for preparing bamboo activated carbon comprises the following steps: Preparation of N-doped titanium dioxide gel: First, 10 g of titanium tetrachloride was added dropwise to 100 g of deionized water. After the solution became clear and transparent, ammonia was slowly added dropwise until the pH value of the solution was neutral. Finally, 20 g of N-doped titanium dioxide gel was obtained by concentration. Preparation of bamboo activated carbon powder: Preparation of raw material powder: crush and grind the bamboo raw material, and sieve to obtain 60-80 mesh bamboo raw material powder; Primary deashing: The bamboo raw material powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 30-50°C for 50-70 minutes, then washed with deionized water at 30-50°C until neutral and dried to obtain primary deashing powder; Primary carbonization: placing the primary deashing powder in an argon protective atmosphere, heating it to 400-600°C at a rate of 7-8°C / min, then carbonizing it for 100-120min, and finally cooling it to room temperature to obtain primary carbonized powder; Organic solvent attachment: soak the primary carbonized powder in o-xylene solvent at a ratio of 1g:10ml for 1-3h, and then dry it to obtain the pre-treated powder; Secondary carbonization: The pretreated powder is mixed with sodium hydroxide in a mass ratio of 5:1, and then placed in an argon protective atmosphere, heated to 900-1200°C at a rate of 5-10°C / min, and then carbonized for 50-70 minutes, and finally cooled to room temperature to obtain secondary carbonized powder; Carbon black separation: Place the secondary carbonized powder in ethanol at a ratio of 1g:10ml, heat it to 180-220℃ at a rate of 4-6℃ / min, and evaporate and stir at a stirring speed of 400-600r / min to obtain post-treated secondary carbonized powder; Secondary deashing: the post-treated secondary carbonized powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 30-50°C for 50-70 min, then washed with deionized water and water at 30-50°C until neutral and dried to obtain secondary deashed powder; Activation: Place the secondary deashing powder in a steam activation device and activate it at 700-900℃ for 2-4h to obtain the raw bamboo activated carbon powder; Preparation of activated carbon solution: Add 0.12 g thiourea and 0.2 g bamboo activated carbon powder into 100 ml deionized water, mix and stir evenly, then slowly add hydrochloric acid until the pH value of the mixture is 2.5 to obtain an activated carbon solution; Preparation of pretreated bamboo activated carbon: N-doped titanium dioxide gel is added dropwise to the activated carbon solution for mixing at a mixing temperature of 75°C for 24 hours, followed by drying at 100-120°C for 6-18 hours, and then calcining at 300-400°C for 2-4 hours, and finally grinding to obtain pretreated bamboo activated carbon; Preparation of bamboo activated carbon: First, the pretreated bamboo activated carbon is placed in an environment of 100-120°C for drying, then immersed in a 10-20% citric acid aqueous solution at a ratio of 1g:2ml, shaken and immersed at a temperature of 20-40°C for 40-50h, and finally filtered and dried to obtain bamboo activated carbon.

[0023] In summary, this application has the following beneficial effects: 1. When titanium dioxide is loaded on bamboo activated carbon, since titanium dioxide has a certain photocatalytic effect, when it is exposed to light, the electrons in titanium dioxide will cross the forbidden band from the valence band and then jump to the conduction band, thereby generating corresponding holes in the valence band. These photogenerated electrons and holes with redox activity convert oxygen and water molecules into highly oxidizing ·O2 and ·OH, respectively, thereby quickly reacting the ammonia adsorbed on the bamboo activated carbon to generate NO, NO2 or N2, thereby achieving the effect of purifying ammonia.

[0024] 2. Since the place where ammonia is treated is basically an indoor environment such as a bathroom, and the light in the indoor environment is mainly reflected light and scattered light, the lighting effect is not good, which leads to insufficient photocatalytic effect of titanium dioxide. When titanium dioxide is loaded with N, N can cause more defects in titanium dioxide. At the same time, nitrogen can also replace oxygen to form nitrogen oxide in the form of bonds, so that titanium dioxide can capture more charge carriers and inhibit the recombination of electrons and holes, thereby enhancing the photocatalytic effect of titanium dioxide.

[0025] 3. Ammonia, as an alkaline gas, can combine with acidic sites. Therefore, constructing acidic sites on the surface of bamboo activated carbon can further enhance the adsorption effect of bamboo activated carbon on ammonia. As the number and strength of acidic sites increase, the adsorption effect becomes stronger. Organic acid modification can promote the formation of a large number of carboxyl functional groups on the surface of bamboo activated carbon, and the carboxyl functional groups can react chemically with ammonia to achieve the effect of adsorbing ammonia. The types of organic acids include citric acid, acetic acid, etc., but because the molecular formula of citric acid contains three carboxyl groups, the carboxyl content per mol of citric acid is higher, so compared with acetic acid modification, citric acid-modified bamboo activated carbon has a better ammonia adsorption effect. DETAILED DESCRIPTION

[0026] The present application is further described in detail below in conjunction with Examples 1-5 and Comparative Examples 1-2.

[0027] raw material Bamboo materials: Jingxi Bamboo Industry; Titanium tetrachloride CAS: 7550-45-0; Ammonia CAS: 13767-16-3; Hydrochloric acid CAS: 7647-01-0; Sodium hydroxide CAS: 1310-73-2; O-xylene CAS: 95-47-6; Ethanol CAS: 64-17-5; Citric acid CAS: 77-92-9; Acetic acid CAS: 64-19-7; Thiourea CAS: 62-56-6.

[0028] A bamboo activated carbon, the preparation of which comprises the following steps: Preparation of raw material powder: crush and grind the bamboo raw material, and sieve to obtain 80-mesh bamboo raw material powder; Deashing: The bamboo raw material powder was acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 40°C for 60 min, then washed with deionized water and water at 40°C until neutral and dried to obtain deashed powder; Carbonization: The primary deashing powder is placed in an argon protective atmosphere, the temperature is raised to 500°C at a rate of 8°C / min, and then carbonized for 110 minutes, and finally cooled to room temperature to obtain carbonized powder; Activation: The carbonized powder was placed in a steam activation device with a steam flow rate of 10 ml / min and activated at 800°C for 3 h to obtain bamboo activated carbon raw powder; Preparation of N-doped titanium dioxide gel: First, 10 g of titanium tetrachloride was added dropwise to 100 g of deionized water. After the solution became clear and transparent, ammonia was slowly added dropwise until the pH value of the solution was neutral. Finally, 20 g of N-doped titanium dioxide gel was obtained by concentration. Preparation of activated carbon solution: Add 0.12 g thiourea and 0.2 g bamboo activated carbon powder into 100 ml deionized water, mix and stir evenly, then slowly add hydrochloric acid until the pH value of the mixture is 2.5 to obtain an activated carbon solution; Preparation of bamboo activated carbon: N-doped titanium dioxide gel was added dropwise to the activated carbon solution for mixing at a mixing temperature of 75°C for 24 hours, followed by drying at 110°C for 12 hours, and then calcining at 400°C for 3 hours, and finally grinding to obtain bamboo activated carbon.

[0029] A bamboo activated carbon, the preparation of which comprises the following steps: Preparation of raw material powder: crush and grind the bamboo raw material, and sieve to obtain 80-mesh bamboo raw material powder; Primary deashing: The bamboo raw material powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 40°C for 60 min, then washed with deionized water at 40°C until neutral and dried to obtain primary deashed powder; Primary carbonization: the primary deashing powder is placed in an argon protective atmosphere, heated to 500°C at a rate of 8°C / min, and then carbonized for 110 minutes, and finally cooled to room temperature to obtain primary carbonized powder; Secondary carbonization: the primary carbonized powder was mixed with sodium hydroxide in a mass ratio of 5:1, and then placed in an argon protective atmosphere, heated to 1100°C at a rate of 8°C / min, and then carbonized for 60 minutes, and finally cooled to room temperature to obtain secondary carbonized powder; Secondary deashing: the secondary carbonized powder was acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 40°C for 60 min, then washed with deionized water at 40°C until neutral and dried to obtain secondary deashed powder; Activation: Place the secondary deashing powder in a steam activation device with a steam flow rate of 10 ml / min and activate at 800 ° C for 3 hours to obtain bamboo activated carbon raw powder; Preparation of N-doped titanium dioxide gel: First, 10 g of titanium tetrachloride was added dropwise to 100 g of deionized water. After the solution became clear and transparent, ammonia was slowly added dropwise until the pH value of the solution was neutral. Finally, 20 g of N-doped titanium dioxide gel was obtained by concentration. Preparation of activated carbon solution: Add 0.12 g thiourea and 0.2 g bamboo activated carbon powder into 100 ml deionized water, mix and stir evenly, then slowly add hydrochloric acid until the pH value of the mixture is 2.5 to obtain an activated carbon solution; Preparation of bamboo activated carbon: N-doped titanium dioxide gel was added dropwise to the activated carbon solution for mixing at a mixing temperature of 75°C for 24 hours, followed by drying at 110°C for 12 hours, and then calcining at 400°C for 3 hours, and finally grinding to obtain bamboo activated carbon.

[0030] A bamboo activated carbon, the preparation of which comprises the following steps: Preparation of raw material powder: crush and grind the bamboo raw material, and sieve to obtain 80-mesh bamboo raw material powder; Primary deashing: The bamboo raw material powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 40°C for 60 min, then washed with deionized water at 40°C until neutral and dried to obtain primary deashed powder; Primary carbonization: the primary deashing powder is placed in an argon protective atmosphere, heated to 500°C at a rate of 8°C / min, and then carbonized for 110 minutes, and finally cooled to room temperature to obtain primary carbonized powder; Organic solvent attachment: soak the primary carbonized powder in toluene solvent at a ratio of 1g:10ml for 1-3h, and then dry it to obtain the pretreated powder; Secondary carbonization: the primary carbonized powder was mixed with sodium hydroxide in a mass ratio of 5:1, and then placed in an argon protective atmosphere, heated to 1100°C at a rate of 8°C / min, and then carbonized for 60 minutes, and finally cooled to room temperature to obtain secondary carbonized powder; Carbon black separation: Place the secondary carbonized powder in ethanol at a ratio of 1g:10ml, heat it to 180-220℃ at a rate of 4-6℃ / min, and evaporate and stir at a stirring speed of 400-600r / min to obtain post-treated secondary carbonized powder; Secondary deashing: The secondary carbonized powder was acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 40°C for 60 min, then washed with deionized water and water at 40°C until neutral and dried to obtain secondary deashed powder; Activation: Place the secondary deashing powder in a steam activation device with a steam flow rate of 10 ml / min and activate at 800 ° C for 3 hours to obtain bamboo activated carbon raw powder; Preparation of N-doped titanium dioxide gel: First, 10 g of titanium tetrachloride was added dropwise to 100 g of deionized water. After the solution became clear and transparent, ammonia was slowly added dropwise until the pH value of the solution was neutral. Finally, 20 g of N-doped titanium dioxide gel was obtained by concentration. Preparation of activated carbon solution: Add 0.12 g thiourea and 0.2 g bamboo activated carbon powder into 100 ml deionized water, mix and stir evenly, then slowly add hydrochloric acid until the pH value of the mixture is 2.5 to obtain an activated carbon solution; Preparation of bamboo activated carbon: N-doped titanium dioxide gel was added dropwise to the activated carbon solution for mixing at a mixing temperature of 75°C for 24 hours, followed by drying at 110°C for 12 hours, and then calcining at 400°C for 3 hours, and finally grinding to obtain bamboo activated carbon.

[0031] Comparative Example 4 After the surface of the raw bamboo activated carbon powder was loaded with N-doped titanium dioxide, it was also modified with citric acid; The steps of citric acid modification are as follows: first, the raw powder of bamboo activated carbon loaded with N-doped titanium dioxide is placed in an environment of 110°C for drying, then immersed in a 60% citric acid aqueous solution at a ratio of 1g:2ml, shaken and immersed at a temperature of 30°C for 50h, and finally filtered and dried to obtain bamboo activated carbon.

[0032] Comparative Example 5 After the surface of the raw bamboo activated carbon powder was loaded with N-doped titanium dioxide, it was also modified with acetic acid; The steps of acetic acid modification are as follows: first, the raw powder of bamboo activated carbon loaded with N-doped titanium dioxide is placed in an environment of 110°C for drying, then immersed in a 60% acetic acid aqueous solution at a ratio of 1g:2ml, shaken and immersed at a temperature of 30°C for 50h, and finally filtered and dried to obtain bamboo activated carbon.

[0033] Comparative Example Comparative Example 1 A bamboo activated carbon, the preparation method of which comprises the following steps: Preparation of raw material powder: crush and grind the bamboo raw material, and sieve to obtain 80-mesh bamboo raw material powder; Deashing: The bamboo raw material powder was acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 40°C for 60 min, then washed with deionized water and water at 40°C until neutral and dried to obtain deashed powder; Carbonization: The primary deashing powder is placed in an argon protective atmosphere, the temperature is raised to 500°C at a rate of 8°C / min, and then carbonized for 110 minutes, and finally cooled to room temperature to obtain carbonized powder; Activation: The carbonized powder was placed in a steam activation device with a steam flow rate of 10 ml / min and activated at 800°C for 3 h to obtain bamboo activated carbon.

[0034] Comparative Example 2 A bamboo activated carbon, the preparation of which comprises the following steps: Preparation of raw material powder: crush and grind the bamboo raw material, and sieve to obtain 60-80 mesh bamboo raw material powder; Preparation of raw material powder: crush and grind the bamboo raw material, and sieve to obtain 80-mesh bamboo raw material powder; Deashing: The bamboo raw material powder was acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 40°C for 60 min, then washed with deionized water and water at 40°C until neutral and dried to obtain deashed powder; Carbonization: The primary deashing powder is placed in an argon protective atmosphere, the temperature is raised to 500°C at a rate of 8°C / min, and then carbonized for 110 minutes, and finally cooled to room temperature to obtain carbonized powder; Activation: The carbonized powder was placed in a steam activation device with a steam flow rate of 10 ml / min and activated at 800°C for 3 h to obtain bamboo activated carbon raw powder; Preparation of titanium dioxide treatment solution: First, add 10g of titanium tetrachloride dropwise into 100g of deionized water, and when the solution becomes clear and transparent, slowly add sodium hydroxide until the pH value of the solution is neutral, and finally concentrate to obtain 20g of titanium dioxide treatment solution; Preparation of activated carbon solution: Add 0.12 g thiourea and 0.2 g bamboo activated carbon powder into 100 ml deionized water, mix and stir evenly, then slowly add hydrochloric acid until the pH value of the mixture is 2.5 to obtain an activated carbon solution; Preparation of bamboo activated carbon: Add titanium dioxide treated liquid dropwise into the activated carbon solution and mix them at a mixing temperature of 75°C for 24 hours. Then dry them at 110°C for 12 hours, and then calcine them at 400°C for 3 hours. Finally, grind them to obtain bamboo activated carbon.

[0035] Performance testing Detection Methods Ammonia adsorption treatment performance test Three samples were taken from Examples 1-5 and Comparative Examples 1-2, respectively, and 10 g of each sample was placed in a closed space of 250 mm × 200 mm × 100 mm. Ammonia gas was injected into the closed space at an initial concentration of 80 mg / m 3 , and then let it stand still in the room for 1 hour, then measure the real-time concentration of ammonia in the enclosed space, and finally calculate the ammonia removal rate.

[0036] The experimental temperature is 25℃, the experimental humidity is 50%, and the detection method refers to HJ533-2009 "Nessler's reagent spectrophotometric method for determination of ammonia in ambient air and waste gas"; Ammonia removal rate = (original ammonia concentration - real-time ammonia concentration) / original ammonia concentration × 100%.

[0037] The test data are shown in Table 1.

[0038] Table 1 Ammonia removal rate of Examples 1-5 and Comparative Examples 1-2 / % Ammonia removal rate / % Ammonia removal rate / % Example 1 92.1% Example 5 96.0% Example 2 93.6% Comparative Example 1 20.3% Example 3 94.4% Comparative Example 2 83.9% Example 4 96.8% Referring to Comparative Examples 1-2 and in combination with Table 1, it can be seen that compared with Comparative Example 1, the ammonia removal rate of Comparative Example 2 is significantly improved, which shows that the doping of titanium dioxide can effectively improve the ammonia adsorption treatment performance of bamboo activated carbon.

[0039] The reason is that when bamboo activated carbon is loaded with titanium dioxide, since titanium dioxide has a certain photocatalytic effect, when it is exposed to light, the electrons in titanium dioxide will cross the forbidden band from the valence band and then jump to the conduction band, thereby generating corresponding holes in the valence band. These photogenerated electrons and holes with redox activity convert oxygen and water molecules into highly oxidizing ·O2 and ·OH, respectively, thereby quickly reacting the ammonia adsorbed on the bamboo activated carbon to generate NO, NO2 or N2, thereby achieving the effect of purifying ammonia.

[0040] Referring to Example 1 and Comparative Example 2 and in combination with Table 1, it can be seen that, relative to Comparative Example 2, the ammonia removal rate of Example 1 is further improved, which indicates that, relative to the use of sodium hydroxide for alkali neutralization, the use of ammonia for alkali neutralization can promote the bamboo activated carbon to have better ammonia adsorption treatment performance.

[0041] The reason is that when ammonia is used for alkaline neutralization, the surface of titanium dioxide will be doped with N elements. Since the light in the indoor environment is mainly reflected light and scattered light, the illumination effect is not good, which leads to insufficient photocatalytic effect of titanium dioxide. However, when N is loaded on titanium dioxide, N can cause more defects in titanium dioxide. At the same time, nitrogen can also replace oxygen to form nitrogen oxide in the form of bonds, so that titanium dioxide can capture more charge carriers and inhibit the recombination of electrons and holes, thereby enhancing the photocatalytic effect of titanium dioxide.

[0042] With reference to Examples 1-2 and in combination with Table 1, it can be seen that, relative to Example 1, the ammonia removal rate of Example 2 is further improved, which indicates that the microporous treatment can further improve the ammonia adsorption treatment capacity of the bamboo activated carbon.

[0043] The reason is that although loading N-doped titanium dioxide on bamboo activated carbon can give bamboo activated carbon the function of purifying ammonia, N-doped titanium dioxide is usually loaded on the micropores of bamboo activated carbon, and the reduction of micropores will significantly reduce the adsorption of ammonia by bamboo activated carbon.

[0044] In the microporation treatment, the raw materials are deashed multiple times through acid washing and deionized water treatment, and the alkalinity fully removes the impurity elements in the raw materials, so as to further form pores in the subsequent activation process, thereby compensating for the problem of decreased adsorption after bamboo activated carbon is loaded with N-doped titanium dioxide.

[0045] Referring to Examples 2-3 and in combination with Table 1, it can be seen that, relative to Example 2, the ammonia removal rate of Example 3 is further improved, which indicates that the operation of organic solvent attachment and carbon black separation can further improve the ammonia adsorption treatment performance of bamboo activated carbon.

[0046] The reason is that after the first carbonization, the organic solvent is first attached, and then under high temperature, the organic solvent is cracked to produce carbon black, and then the carbon black is removed with ethanol, thereby obtaining more micropores and further improving the adsorption performance of bamboo activated carbon.

[0047] Referring to Examples 3-5 and in combination with Table 1, it can be seen that, relative to Example 3, the ammonia removal rates of Examples 4-5 are further improved, which indicates that treating the surface of bamboo activated carbon with organic acid can further improve the ammonia adsorption treatment performance of bamboo activated carbon.

[0048] The reason is that ammonia, as an alkaline gas, can combine with acidic sites. Therefore, constructing acidic sites on the surface of bamboo activated carbon can further enhance the adsorption effect of bamboo activated carbon on ammonia, and as the number and strength of acidic sites increase, the adsorption effect is stronger; organic acid modification can promote the formation of a large number of carboxyl functional groups on the surface of bamboo activated carbon, and the carboxyl functional groups can react chemically with ammonia, thereby achieving the effect of adsorbing ammonia.

[0049] Among them, compared with Example 5, the ammonia removal rate of Example 4 is relatively higher, which shows that compared with acetic acid modification, citric acid modification can further improve the ammonia adsorption treatment performance of bamboo activated carbon.

[0050] The reason may be that the molecular formula of citric acid contains three carboxyl groups, which leads to a higher carboxyl content per mol of citric acid. Therefore, compared with acetic acid modification, citric acid-modified bamboo activated carbon has a better ammonia adsorption effect.

[0051] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A bamboo activated carbon, characterized in that: The bamboo activated carbon is raw bamboo activated carbon powder with N-doped titanium dioxide loaded on the surface, and the N-doped titanium dioxide is added in the form of gel.

2. The bamboo activated carbon according to claim 1, characterized in that: The preparation method of the N-doped titanium dioxide gel is as follows: first, 10 g of titanium tetrachloride is dropped into 100 g of deionized water, and after the solution becomes clear and transparent, ammonia water is slowly added until the pH value of the solution is neutral, so as to obtain the N-doped titanium dioxide gel.

3. The bamboo activated carbon according to claim 1, characterized in that: The raw bamboo activated carbon powder is processed into micropores.

4. The bamboo activated carbon according to claim 3, characterized in that: The microporation treatment comprises the following steps: Preparation of raw material powder: crush and grind the bamboo raw material, and sieve to obtain 60-80 mesh bamboo raw material powder; Primary deashing: The bamboo raw material powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 30-50°C for 50-70 minutes, then washed with deionized water at 30-50°C until neutral and dried to obtain primary deashing powder; Primary carbonization: placing the primary deashing powder in an argon protective atmosphere, heating it to 400-600°C at a rate of 7-8°C / min, then carbonizing it for 100-120min, and finally cooling it to room temperature to obtain primary carbonized powder; Secondary carbonization: the primary carbonized powder is mixed with sodium hydroxide in a mass ratio of 5:1, then placed in an argon protective atmosphere, heated to 900-1200°C at a rate of 5-10°C / min, then carbonized for 50-70min, and finally cooled to room temperature to obtain secondary carbonized powder; Secondary deashing: The secondary carbonized powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 30-50°C for 50-70 min, then washed with deionized water and water at 30-50°C until neutral and dried to obtain secondary deashed powder; Activation: Place the secondary deashing powder in a steam activation device and activate it at 700-900°C for 2-4 hours to obtain bamboo activated carbon raw powder.

5. The bamboo activated carbon according to claim 4, characterized in that: The microporation treatment comprises the following steps: Preparation of raw material powder: crush and grind the bamboo raw material, and sieve to obtain 60-80 mesh bamboo raw material powder; Primary deashing: The bamboo raw material powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 30-50°C for 50-70 minutes, then washed with deionized water at 30-50°C until neutral and dried to obtain primary deashing powder; Primary carbonization: placing the primary deashing powder in an argon protective atmosphere, heating it to 400-600°C at a rate of 7-8°C / min, then carbonizing it for 100-120min, and finally cooling it to room temperature to obtain primary carbonized powder; Organic solvent attachment: soak the primary carbonized powder in o-xylene solvent at a ratio of 1g:10ml for 1-3h, and then dry it to obtain the pre-treated powder; Secondary carbonization: The pretreated powder is mixed with sodium hydroxide in a mass ratio of 5:1, and then placed in an argon protective atmosphere, heated to 900-1200°C at a rate of 5-10°C / min, and then carbonized for 50-70 minutes, and finally cooled to room temperature to obtain secondary carbonized powder; Carbon black separation: Place the secondary carbonized powder in ethanol at a ratio of 1g:10ml, heat it to 180-220℃ at a rate of 4-6℃ / min, and evaporate and stir at a stirring speed of 400-600r / min to obtain post-treated secondary carbonized powder; Secondary deashing: the post-treated secondary carbonized powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 30-50°C for 50-70 min, then washed with deionized water and water at 30-50°C until neutral and dried to obtain secondary deashed powder; Activation: Place the secondary deashing powder in a steam activation device and activate it at 700-900°C for 2-4 hours to obtain bamboo activated carbon raw powder.

6. The bamboo activated carbon according to claim 5, characterized in that: After the surface of the raw bamboo activated carbon powder is loaded with N-doped titanium dioxide, it is also modified with citric acid.

7. The bamboo activated carbon according to claim 6, characterized in that: The steps of citric acid modification are as follows: firstly, the raw powder of bamboo activated carbon loaded with N-doped titanium dioxide is placed in an environment of 100-120° C. for drying, then immersed in a 50-70% citric acid aqueous solution at a ratio of 1 g:2 ml, and shaken and immersed at a temperature of 20-40° C. for 40-50 hours, and finally filtered and dried to obtain bamboo activated carbon.

8. A method for preparing bamboo activated carbon according to any one of claims 1 to 7, characterized in that: The following steps are involved: Preparation of N-doped titanium dioxide gel: First, 10 g of titanium tetrachloride was added dropwise to 100 g of deionized water. After the solution became clear and transparent, ammonia was slowly added dropwise until the pH value of the solution was neutral. Finally, 20 g of N-doped titanium dioxide gel was obtained by concentration. Preparation of activated carbon solution: Add 0.12 g thiourea and 0.2 g bamboo activated carbon powder into 100 ml deionized water, mix and stir evenly, then slowly add hydrochloric acid until the pH value of the mixture is 2.5 to obtain an activated carbon solution; Preparation of bamboo activated carbon: N-doped titanium dioxide gel was added dropwise to the activated carbon solution for mixing at a mixing temperature of 75°C for 24 hours, followed by drying at 100-120°C for 6-18 hours, and then calcining at 300-400°C for 2-4 hours, and finally grinding to obtain bamboo activated carbon.

9. A method for preparing bamboo activated carbon according to any one of claims 6 to 7, characterized in that: The following steps are involved: Preparation of N-doped titanium dioxide gel: First, 10 g of titanium tetrachloride was added dropwise to 100 g of deionized water. After the solution became clear and transparent, ammonia was slowly added dropwise until the pH value of the solution was neutral. Finally, 20 g of N-doped titanium dioxide gel was obtained by concentration. Preparation of bamboo activated carbon powder: Preparation of raw material powder: crush and grind the bamboo raw material, and sieve to obtain 60-80 mesh bamboo raw material powder; Primary deashing: The bamboo raw material powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 30-50°C for 50-70 minutes, then washed with deionized water at 30-50°C until neutral and dried to obtain primary deashing powder; Primary carbonization: placing the primary deashing powder in an argon protective atmosphere, heating it to 400-600°C at a rate of 7-8°C / min, then carbonizing it for 100-120min, and finally cooling it to room temperature to obtain primary carbonized powder; Organic solvent attachment: soak the primary carbonized powder in o-xylene solvent at a ratio of 1g:10ml for 1-3h, and then dry it to obtain the pre-treated powder; Secondary carbonization: The pretreated powder is mixed with sodium hydroxide in a mass ratio of 5:1, and then placed in an argon protective atmosphere, heated to 900-1200°C at a rate of 5-10°C / min, and then carbonized for 50-70 minutes, and finally cooled to room temperature to obtain secondary carbonized powder; Carbon black separation: Place the secondary carbonized powder in ethanol at a ratio of 1g:10ml, heat it to 180-220℃ at a rate of 4-6℃ / min, and evaporate and stir at a stirring speed of 400-600r / min to obtain post-treated secondary carbonized powder; Secondary deashing: the post-treated secondary carbonized powder is acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 30-50°C for 50-70 min, then washed with deionized water and water at 30-50°C until neutral and dried to obtain secondary deashed powder; Activation: Place the secondary deashing powder in a steam activation device and activate it at 700-900℃ for 2-4h to obtain the raw bamboo activated carbon powder; Preparation of activated carbon solution: Add 0.12 g thiourea and 0.2 g bamboo activated carbon powder into 100 ml deionized water, mix and stir evenly, then slowly add hydrochloric acid until the pH value of the mixture is 2.5 to obtain an activated carbon solution; Preparation of pretreated bamboo activated carbon: N-doped titanium dioxide gel is added dropwise to the activated carbon solution for mixing at a mixing temperature of 75°C for 24 hours, followed by drying at 100-120°C for 6-18 hours, and then calcining at 300-400°C for 2-4 hours, and finally grinding to obtain pretreated bamboo activated carbon; Preparation of bamboo activated carbon: First, the pretreated bamboo activated carbon is placed in an environment of 100-120°C for drying, then immersed in a 10-20% citric acid aqueous solution at a ratio of 1g:2ml, shaken and immersed at a temperature of 20-40°C for 40-50h, and finally filtered and dried to obtain bamboo activated carbon.