Ion-functionalized biochar material as well as preparation method and application thereof

Abstract

The invention discloses an ion functionalized biochar material and a preparation method and application thereof, and relates to the field of biochar-based materials, biomass charcoal and sodium amide are mixed and subjected to primary antipyresis for 5-30 min in a protective atmosphere at the temperature of 450-750 DEG C, and sodium amide modified biochar is obtained; mixing the sodium amide modified biochar with chloride and deionized water, carrying out dipping treatment, taking out the sodium amide modified biochar after dipping treatment, and carrying out secondary pyrolysis for 5-30 minutes in a protective atmosphere at the temperature of 450-750 DEG C, so as to obtain the ion functionalized biochar material. Through the short-time pyrolysis and impregnation processing technology, the processing process is simple and convenient to operate, the preparation period is greatly shortened, and the energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the field of biochar-based materials, in particular to an ion-functionalized biochar material and a preparation method and application thereof. Background Art

[0002] As an adsorption material with a rich pore structure and large specific surface area, biochar has shown great application potential in wastewater treatment and CO2 gas adsorption, and is also a potential raw material for the preparation of supercapacitor materials. However, the pore structure and specific surface area of biochar directly obtained by burning raw materials still need to be improved, resulting in limited adsorption capacity for pollutants and CO2 gas in wastewater. In terms of supercapacitor material application, biochar cannot meet the performance requirements of high specific surface area and good pore structure.

[0003] At present, in order to improve the adsorption performance and related physical and chemical properties of biochar, it is usually necessary to modify and activate biochar. The main purpose is to increase the specific surface area of biochar and optimize the pore structure, while further enriching its surface functional groups and mineral binding sites.

[0004] For example, the Chinese invention patent application number CN202111283499.8 discloses a method for preparing and applying lees-based biochar for deep dechromization of wet-process phosphoric acid. Specifically, the carbonized product and the activator are fully mixed according to a mass ratio, the mixture is spread evenly in a covered porcelain boat, and the covered porcelain boat is placed in the quartz tube constant temperature zone of a tube furnace, the heating rate is increased to 600-1000°C, and the temperature is kept constant for 2-5 hours, and then naturally cooled to room temperature to obtain an activated product; the prepared lees-based biochar has a high specific surface area of 1000-3800m 2 ·g -1 , and there are rich oxygen-containing functional groups on the surface, which can achieve high chromium adsorption capacity and excellent adsorption performance.

[0005] However, existing biochar modification methods have limitations. The modification time is long and it is difficult to fully tap the application potential of biochar. It is impossible to efficiently and stably prepare high-performance biochar materials that meet diverse application needs. Summary of the Invention

[0006] The present invention provides an ion-functionalized biochar material, a preparation method and an application thereof, so as to prepare a high-performance biochar material that meets diverse application requirements within a relatively short pyrolysis time.

[0007] In order to achieve the above-mentioned purpose, the specific scheme adopted by the present invention is: a method for preparing an ion-functionalized biochar material, wherein biochar is mixed with sodium amide and pyrolyzed for 5 to 30 minutes in a protective atmosphere at a temperature of 450 to 750°C to obtain sodium amide-modified biochar; the sodium amide-modified biochar is mixed with chloride and deionized water for impregnation treatment, and after the impregnation is completed, the sodium amide-modified biochar is taken out and pyrolyzed for a second time for 5 to 30 minutes in a protective atmosphere at a temperature of 450 to 750°C to obtain the ion-functionalized biochar material.

[0008] As a further optimization of the above technical solution, the mass ratio of biochar to sodium amide is 1:1-5.

[0009] As a further optimization of the above technical solution, the impregnation ratio of sodium amide modified biochar to metal ions is 3-20%, and the mass ratio of chloride to deionized water is 0.2-1.5%.

[0010] As a further optimization of the above technical solution, the metal ion is at least one of barium, iron, ammonium, zinc, lanthanum and zirconium.

[0011] As a further optimization of the above technical solution, the biochar and sodium amide are acid-washed with 5-20 wt.% HCl to neutrality after the primary pyrolysis, and the solid matter is separated and dried to obtain sodium amide-modified biochar.

[0012] As a further optimization of the above technical solution, biochar is produced by primary pyrolysis of biomass raw materials at a temperature of 400 to 800° C. for 2 to 40 minutes.

[0013] As a further optimization of the above technical solution, the biomass raw material is at least one of bamboo branches, bamboo leaves, and bamboo nodes, which is washed, dried at a temperature of 80 to 120° C., crushed, and sieved through a 30 to 140 mesh screen.

[0014] The ion-functionalized biochar material is prepared by the above-mentioned preparation method.

[0015] The application of ion-functionalized biochar materials as CO2 gas adsorbents, supercapacitor positive electrode materials, supercapacitor negative electrode materials and high molecular organic adsorbents in active dyes in printing and dyeing wastewater.

[0016] As a further optimization of the above technical solution, the high molecular organic matter in the reactive dyes in printing and dyeing wastewater is at least one of Congo red, methylene blue, malachite green, tetracycline, rhodamine B or reactive black.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The method for preparing ion-functionalized biochar materials provided by the present invention has a simple processing process through a short-time pyrolysis and impregnation process, which greatly shortens the preparation cycle and reduces energy consumption. By virtue of the short-time pyrolysis-sodium amide modification-ion loading synergistic process, the biochar material can achieve structural optimization and functional improvement in a short time. After sodium amide modification and ion loading, the specific surface area and pore structure of the biochar are significantly improved, and the surface functional groups and mineral binding sites are more abundant, which significantly enhances the material's adsorption performance for pollutants in wastewater and CO2 gas, as well as its application potential in the field of supercapacitors. In addition, the preparation method of the present invention has a simple process, low equipment requirements, and is easy to mass produce. It can stably produce high-performance ion-functionalized biochar materials to meet the needs of industrial production.

[0019] The present invention uses cheap biomass solid waste as the base material, which not only effectively solves the problem of waste disposal, but also realizes the recycling of resources, broadens the source channels of raw materials, greatly reduces production costs, and meets the needs of circular economic development.

[0020] The ion-functionalized biochar material provided by the present invention uses a biochar material with rich pore structure, large specific surface area and rich polar groups as the matrix material, and is modified with a large number of inorganic salt ions in its pores and surface. The ion-functionalized biochar material exhibits a good adsorption effect on various active dyes, tetracycline and CO2 gas, and has excellent capacity and cycle stability as a supercapacitor material.

[0021] The ion-functionalized biochar material provided by the present invention can be widely used as an adsorption material for the adsorption of high-molecular organic compounds in reactive dyes from printing and dyeing wastewater, demonstrating high adsorption performance. After 10 minutes of adsorption, the adsorption rates for methylene blue reached 88.93%, rhodamine B 88.23%, Congo red 90.85%, tetracycline 99.73%, malachite green 98.42%, and reactive black 89.69%. This achieves highly efficient adsorption of high-molecular organic compounds in printing and dyeing wastewater, and after regeneration, the adsorption efficiency reached 84.28%, demonstrating excellent cyclic stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The modified carbons obtained by mixing bamboo charcoal and sodium amide in a mass ratio of 1:1 to 5 in the present invention are as follows from left to right: unmodified, GN-1-BC, GN-2-BC, GN-3-BC, GN-4-BC, GN-5-BC;

[0023] Figure 2Ion-functionalized biochar materials obtained with different loading ions and different impregnation ratios in Examples 1 to 6 of the present invention, from left to right: Fe-10%-2BC, Co-10%-3BC, La-10%-1BC, Zn-5%-2BC, Ba-5%-4BC, Zr-10%-4BC;

[0024] Figure 3 Comparative diagrams of the effects of adsorbing different high-molecular organic compounds in reactive dyes on the ion-functionalized biochar materials prepared in Examples 1 to 6 of the present invention. In Figures i-vi, the left conical flask contains the solution after adsorption by unmodified bamboo charcoal, and the right conical flask contains the solution after adsorption by metal ion-loaded biochar.

[0025] Figure ⅰ corresponds to Example 1, that is, when the carbon dosage is 0.02 g, the adsorption of Rhodamine B by the obtained ion-functionalized biochar material;

[0026] Figure ⅱ corresponds to Example 2, i.e., when the carbon dosage is 0.01 g, the adsorption of methylene blue by the obtained ion-functionalized biochar material;

[0027] Figure ⅲ corresponds to Example 3, i.e., when the carbon dosage is 0.02 g, the adsorption of Congo red by the obtained ion-functionalized biochar material;

[0028] Figure ⅳ corresponds to Example 4, i.e., when the carbon dosage is 0.01 g, the adsorption of tetracycline by the obtained ion-functionalized biochar material;

[0029] Figure V corresponds to Example 5, i.e., when the carbon dosage is 0.02 g, the adsorption of malachite green by the obtained ion-functionalized biochar material;

[0030] Figure ⅵ corresponds to Example 6, that is, when the carbon dosage is 0.03 g, the adsorption of active black by the obtained ion-functionalized biochar material. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further elaborated in detail below in conjunction with specific embodiments. Parts not described and disclosed in detail in the following embodiments of the present invention should be understood as existing technologies known or should be known to those skilled in the art.

[0032] A method for preparing an ion-functionalized biochar material comprises the following steps:

[0033] S1. Place the biomass raw material in a tubular furnace, and under a protective atmosphere, heat it to 400-800°C at a rate of 5-20°C / min for primary pyrolysis. The primary pyrolysis time is 2-40 minutes to obtain biochar (BC).

[0034] The biomass raw material is at least one of bamboo branches, bamboo leaves, and bamboo joints, which is prepared by washing, drying at 80-120°C, crushing, and sieving through a 30-140 mesh sieve. The particle size of the biomass raw material is 30-140 mesh, preferably 40-100 mesh.

[0035] S2. Mix biochar and sodium amide (NaNH2) in a mass ratio of 1:1 to 5, hand-mill or ball-mill for 1 to 30 minutes, transfer to a tube furnace, heat to 450 to 750°C at a rate of 5 to 20°C / min under a protective atmosphere, and perform a primary pyrolysis for 5 to 30 minutes. After the primary pyrolysis, acid wash to neutrality, ultrasonicate, filter, and dry to obtain sodium amide-modified biochar; wherein, 5 to 30 wt.% HCl is used for acid washing, the ultrasonic exhaust time is 10 to 60 minutes, the drying temperature is 50 to 120°C, and the drying time is 5 to 15 hours.

[0036] Preferably, the mass ratio of biochar to sodium amide is 1:2-4, the temperature condition of the primary pyrolysis is 500-700°C, and the time of the primary pyrolysis is 5-20 minutes; 10-2 wt.% HCl is used for pickling, and the time of ultrasonic exhaust is 20-40 minutes; the drying temperature is 70-110°C, and the drying time is 7-9 hours.

[0037] S3. Mix the sodium amide modified biochar with chloride and deionized water for impregnation treatment, ultrasonicate, let it stand, dry, and then heat it to 450-750°C at a rate of 5-20°C / min for secondary pyrolysis. The secondary pyrolysis time is 5-30 minutes, and the ion functionalized biochar material is obtained. The ultrasonic exhaust time is 30-90 minutes, and the standing time is 4-12 hours. The impregnation ratio of sodium amide modified biochar to metal ions is 3-20%, and the metal ions are at least one of barium, iron, ammonium, zinc, lanthanum, and zirconium. The mass ratio of chloride to deionized water is 0.2-1.5%,

[0038] Preferably, the impregnation ratio is 5-15%; the ultrasonic degassing time is 40-70 minutes, and the standing time is 8-10 hours; the secondary pyrolysis conditions are 500-700° C., and the secondary pyrolysis time is 5-20 minutes.

[0039] It should be noted that the impregnation ratio described in the present invention is the impregnation ratio of metal ions in chloride to sodium amide modified biochar.

[0040] The present invention also discloses the use of ion-functionalized biochar materials as adsorbents for high-molecular-weight organic matter in reactive dyes from printing and dyeing wastewater. The high-molecular-weight organic matter in the reactive dyes from printing and dyeing wastewater is at least one of Congo red, methylene blue, malachite green, tetracycline, rhodamine B, or reactive black.

[0041] The ion-functionalized biochar material prepared by the present invention can also be used as a CO2 gas adsorbent.

[0042] The ion-functionalized biochar material prepared by the present invention can also be applied to supercapacitors, which include a positive electrode, a negative electrode, a diaphragm and an electrolyte; the ion-functionalized biochar material serves as the positive electrode material and the negative electrode material of the supercapacitor.

[0043] The present invention uses agricultural waste bamboo branches, bamboo leaves, bamboo joints and other biomass raw materials, and prepares a functional material with rich active sites and developed pore structure through a collaborative process of short-time pyrolysis-sodium amide modification-ion loading. The specific surface area of the material is as high as 3200m 2 / g, and exhibits excellent selective adsorption performance for active dye molecules and tetracycline in printing and dyeing wastewater, with an adsorption efficiency of more than 85% within 10 minutes. At the same time, the material has a good adsorption effect on CO2 gas, with an adsorption capacity of up to 3.52mmol / g. In addition, the material has excellent capacity and cycle stability when used as a supercapacitor electrode material. The green and pollution-free preparation process of the biochar material, with a simple and convenient process, is highly consistent with the current concept of green development in the chemical industry. It only requires a short period of pyrolysis and impregnation to obtain it. It is simple to operate, saves energy, and can be mass-produced.

[0044] In order to avoid repetition, some of the raw materials used in the following examples are described as follows:

[0045] In the following Examples 1-6, the biomass raw materials were prepared by washing bamboo branches, drying at 100° C., crushing, and sieving through a 60-mesh sieve;

[0046] In the following Examples 1-6, the protective atmosphere during pyrolysis (including primary pyrolysis, primary pyrolysis, and secondary pyrolysis) is N2.

[0047] Example 1

[0048] A method for preparing an ion-functionalized biochar material comprises the following steps:

[0049] S1. Place the biomass raw material in a tubular furnace under a protective atmosphere, heat it to 600°C at a rate of 20°C / min for primary pyrolysis, and pyrolysis for 20 min to produce biochar;

[0050] S2. Biochar and sodium amide were mixed in a mass ratio of 1:2, ball-milled for 30 min, transferred to a tube furnace, heated to 700°C at a rate of 10°C / min under a protective atmosphere, and pyrolyzed for 10 min. The mixture was acid-washed with 5 wt.% HCl until neutral, ultrasonically degased for 20 min, filtered, and dried at 110°C for 7 h to obtain sodium amide-modified biochar GN-2-BC.

[0051] S3. According to the impregnation ratio of 10%, 0.2g of the obtained sodium amide modified biochar GN-2-BC was mixed with 0.106g of ferric chloride hexahydrate and 10g of deionized water for impregnation treatment, ultrasonically degassing for 50min, standing for 4h, and drying. The dried solid was subjected to secondary pyrolysis at a pyrolysis temperature of 700℃ and a pyrolysis time of 10min to finally obtain an ion-functionalized biochar material, recorded as Fe-10%-2BC.

[0052] Example 2

[0053] A method for preparing an ion-functionalized biochar material comprises the following steps:

[0054] S1. placing the biomass raw material in a tubular furnace under a protective atmosphere, heating it to 550°C at a rate of 20°C / min for a primary pyrolysis time of 20 min to produce biochar;

[0055] S2. Biochar and sodium amide were mixed in a mass ratio of 1:3, ball-milled for 30 min, transferred to a tube furnace, and pyrolyzed at 600°C at a rate of 10°C / min under a protective atmosphere for 10 min. The mixture was acid-washed with 10 wt.% HCl until neutral, ultrasonically degased for 20 min, filtered, and dried at 100°C for 8 h to obtain sodium amide-modified biochar GN-3-BC.

[0056] S3. According to the impregnation ratio of 10%, 0.1g of the obtained sodium amide modified biochar GN-3-BC was mixed with 0.044g of cobalt chloride hexahydrate and 5g of deionized water for impregnation treatment, ultrasonic exhaust was performed for 90min, the mixture was allowed to stand for 4h, and dried. The dried solid was heated to 550℃ at a rate of 10℃ / min and subjected to secondary pyrolysis for 10min. Finally, the ion functionalized biochar material was obtained, which was recorded as Co-10%-3BC.

[0057] Example 3

[0058] A method for preparing an ion-functionalized biochar material comprises the following steps:

[0059] S1. Place the biomass raw material in a tubular furnace under a protective atmosphere, heat it to 550°C at a rate of 20°C / min, and perform primary pyrolysis for 10 min to produce biochar;

[0060] S2. Biochar and sodium amide were mixed in a mass ratio of 1:1, ball-milled for 30 min, transferred to a tube furnace, and heated to 600°C at a rate of 15°C / min under a protective atmosphere for a pyrolysis time of 10 min. The mixture was acid-washed with 3 wt.% HCl until neutral, ultrasonically degased for 20 min, filtered, and dried at 90°C for 7 h to obtain sodium amide-modified biochar GN-1-BC;

[0061] S3. According to the impregnation ratio of 10%, 0.2g of the obtained sodium amide modified biochar GN-1-BC was mixed with 0.059g of lanthanum chloride heptahydrate and 8g of deionized water, ultrasonically degased for 90min, allowed to stand for 4h, and dried. The dried solid was heated to 600℃ at 10℃ / min for secondary pyrolysis, and the pyrolysis time was 10min to finally obtain the ion functionalized biochar material La-10%-1BC.

[0062] Example 4

[0063] A method for preparing an ion-functionalized biochar material comprises the following steps:

[0064] S1. placing the biomass raw material in a tubular furnace under a protective atmosphere, heating it to 550°C at a rate of 20°C / min for a primary pyrolysis time of 20 min to produce biochar;

[0065] S2. Biochar and sodium amide were mixed in a mass ratio of 1:2, ball-milled for 30 min, transferred to a tube furnace, and heated to 600°C at a rate of 10°C / min under a protective atmosphere for a pyrolysis time of 10 min. The mixture was acid-washed with 2 wt.% HCl until neutral, ultrasonically degased for 20 min, filtered, and dried at 110°C for 7 h to obtain sodium amide-modified biochar GN-2-BC;

[0066] S3. According to the impregnation ratio of 5%, 0.2g of the obtained sodium amide modified biochar GN-2-BC was mixed with 0.013g of zinc chloride aqueous solution and 5g of deionized water, ultrasonically degased for 40min, allowed to stand for 4h, and dried. The dried solid was heated to 600℃ at 10℃ / min for secondary pyrolysis, and the pyrolysis time was 10min. Finally, the ion functionalized biochar material was obtained, which was recorded as Zn-5%-2BC.

[0067] Example 5

[0068] A method for preparing an ion-functionalized biochar material comprises the following steps:

[0069] S1. placing the biomass raw material in a tubular furnace under a protective atmosphere, heating it to 500°C at a rate of 20°C / min for 10 min to perform primary pyrolysis, and producing biochar;

[0070] S2. Biochar and sodium amide were mixed in a mass ratio of 1:4, ball-milled for 30 min, transferred to a tube furnace, heated to 650°C at 10°C / min under a protective atmosphere for a pyrolysis time of 8 min, acid-washed with 10 wt.% HCl until neutral, ultrasonically degased for 20 min, filtered, and dried at 80°C for 7 h to obtain sodium amide-modified biochar GN-4-BC;

[0071] S3. According to the impregnation ratio of 5%, 0.2g of the obtained sodium amide modified biochar GN-4-BC was mixed with 0.023g of barium chloride dihydrate and 6g of deionized water, ultrasonically degased for 40min, allowed to stand for 4h, and dried. The dried solid was heated to 650℃ at a rate of 10℃ / min for secondary pyrolysis, and the pyrolysis time was 8min. Finally, the ion functionalized biochar material was obtained, which was recorded as Ba-5%-4BC.

[0072] Example 6

[0073] A method for preparing an ion-functionalized biochar material comprises the following steps:

[0074] S1. placing the biomass raw material in a tubular furnace under a protective atmosphere, heating it to 500°C at a rate of 20°C / min for 10 min to perform primary pyrolysis, and producing biochar;

[0075] S2. Biochar and sodium amide were mixed in a mass ratio of 1:2, ball-milled for 30 min, transferred to a tube furnace, and heated to 650°C at 15°C / min under a protective atmosphere for a pyrolysis time of 8 min. The mixture was acid-washed with 3 wt.% HCl until neutral, ultrasonically degased for 20 min, filtered, and dried at 110°C for 7 h to obtain sodium amide-modified biochar GN-2-BC;

[0076] S3. According to the impregnation ratio of 10%, 0.2g of the obtained sodium amide modified biochar GN-2-BC was mixed with 0.056g of zirconium chloride and 5g of deionized water, and ultrasonic exhaust was carried out for 90min. The mixture was allowed to stand for 4h and dried. The dried solid was heated to 650℃ at 15℃ / min for secondary pyrolysis. The pyrolysis time was 8min. Finally, the ion functionalized biochar material was obtained, which was recorded as Zr-10%-4BC.

[0077] Application Example 1

[0078] Rhodamine B Adsorption: 0.02 g of the ion-functionalized biochar material prepared in Example 1 was placed in 50 mL of a 100 mg / L rhodamine B solution. Adsorption occurred for 15 minutes in a constant-temperature oscillating chamber at 200 rpm and a temperature of 25°C. Based on the standard curve and relevant instrumental analysis, the adsorption rate of rhodamine B by the ion-functionalized biochar material prepared in Example 1 was 88.23%.

[0079] Application Example 2

[0080] Methylene blue adsorption: 0.01 g of the ion-functionalized biochar material prepared in Example 2 was placed in 50 mL of a methylene blue solution with an initial concentration of 100 mg / L. The adsorption was incubated in a constant temperature shaker at 200 rpm at 25°C for 10 minutes. Based on the standard curve and relevant instrumental analysis, the adsorption rate of methylene blue by the ion-functionalized biochar material prepared in Example 2 was 88.93%.

[0081] Application Example 3

[0082] Congo Red Adsorption: 0.02 g of the ion-functionalized biochar material prepared in Example 3 was placed in 50 mL of Congo Red (initial concentration: 100 mg / L). Adsorption was incubated in a constant temperature shaker at 200 rpm and 25°C for 10 minutes. Based on the standard curve and relevant instrumental analysis, the adsorption rate of methylene blue by the ion-functionalized biochar material prepared in Example 3 was 90.85%.

[0083] Application Example 4

[0084] Tetracycline adsorption: 0.01 g of the ion-functionalized biochar material prepared in Example 4 was placed in 50 mL of a tetracycline solution with an initial concentration of 100 mg / L. Adsorption was incubated in a constant-temperature oscillating chamber at 200 rpm at 25°C for 10 minutes. Based on the standard curve and relevant instrumental analysis, the adsorption rate of tetracycline by the ion-functionalized biochar material prepared in Example 4 was 99.73%.

[0085] Application Example 5

[0086] Malachite Green Adsorption: 0.02 g of the ion-functionalized biochar material prepared in Example 5 was placed in 50 mL of a malachite green solution with an initial concentration of 100 mg / L. Adsorption was carried out for 20 minutes in a constant-temperature oscillating chamber at 200 rpm and a temperature of 25°C. Based on the standard curve and relevant instrumental analysis, the adsorption rate of malachite green by the ion-functionalized biochar material prepared in Example 5 was 98.42%.

[0087] Application Example 6

[0088] Reactive Black Adsorption: 0.03 g of the ion-functionalized biochar material prepared in Example 6 was placed in 50 mL of a 100 mg / L reactive black solution. The adsorption was incubated in a constant-temperature oscillating chamber at 200 rpm and 25°C for 20 minutes. Based on the standard curve and relevant instrumental analysis, the adsorption rate of reactive black by the ion-functionalized biochar material prepared in Example 6 was 89.69%.

[0089] Application Example 7

[0090] Tetracycline adsorption: 0.03 g of the ion-functionalized biochar material prepared in Example 6 was placed in 50 mL of a tetracycline solution with an initial concentration of 100 mg / L. Adsorption was incubated in a constant-temperature oscillating chamber at 200 rpm at 25°C for 30 minutes. Based on the standard curve and relevant instrumental analysis, the adsorption rate of tetracycline by the ion-functionalized biochar material prepared in Example 6 was 67.23%.

[0091] Application Example 8

[0092] CO2 adsorption: 0.003 g of the ion-functionalized biochar material prepared in Example 6 was placed in a thermogravimetric crucible at an initial temperature of 313 K. N2 purge gas was introduced at a flow rate of 30 mL / min, and N2 shielding gas was introduced at a flow rate of 30 mL / min. The temperature was raised at a rate of 10 K / min to 373 K and held at this temperature for 1 h. The temperature was then lowered and raised to the adsorption temperature at a rate of 5 K / min. CO2 purge gas was introduced at a flow rate of 50 mL / min, and N2 shielding gas was set at 10 mL / min. The temperature was then held at this temperature for 1 h. The adsorption capacity of CO2 was 3.52 mmol / g.

[0093] Application Example 9

[0094] As a supercapacitor material, the electrode slurry consisted of 83 wt.% of the ion-functionalized biochar material from Example 4, 10 wt.% of acetylene black (conductive agent), and 10 wt.% of PVFD (binder) (mass ratio of 8:1:1). The slurry was evenly coated on copper foil using a coater, and the electrodes were then dried in a vacuum oven at 80°C for 8 to 20 hours to obtain the supercapacitor positive and negative electrode materials. The supercapacitor retained 90% of its capacity (capacity retention rate reached 92%) after 10,000 cycles at a high current density of 20 A / g, demonstrating its good cycling stability.

[0095] Figure 3Specifically presents a comparison of the effects of the present invention using the ion-functionalized biochar materials prepared according to whether or not carbon is added in Examples 1-6 to adsorb different high-molecular organic substances in the active dyes. The left side of the figure is unmodified bamboo charcoal, and the right side is metal ion-loaded biochar. Figure ⅰ corresponds to Example 1, that is, when the carbon dosage is 0.02g, the colloid of the obtained ion-functionalized biochar material after adsorbing Rhodamine B is light pink; Figure ⅱ corresponds to Example 2, that is, when the carbon dosage is 0.01g, the colloid of the obtained ion-functionalized biochar material after adsorbing methylene blue is lake blue; Figure ⅲ corresponds to Example 3, that is, when the carbon dosage is 0.02g, the colloid of the obtained ion-functionalized biochar material after adsorbing Congo red is rose red; Figure ⅳ corresponds to Example 4, that is, when the carbon dosage is 0.01g, the colloid of the obtained ion-functionalized biochar material after adsorbing After the carbon material adsorbs tetracycline, the colloid is light yellow; Figure V corresponds to Example 5, that is, when the carbon dosage is 0.01g, the colloid of the obtained ion-functionalized biochar material after adsorbing malachite green is dark green; Figure ⅵ corresponds to Example 6, that is, when the carbon dosage is 0.03g, the colloid of the obtained ion-functionalized biochar material after adsorbing active black is dark gray; the results show that the ion-functionalized biochar material exhibits significant adsorption capacity for a variety of dyes and antibiotics, and the color difference of the colloid after adsorption is obvious, which intuitively reflects its excellent pollutant removal performance.

[0096] Figure 3 The present invention specifically presents the prediction of the adsorption mechanism of different high molecular organic matter in reactive dyes using the ion-functionalized biochar materials in Examples 1-6.

[0097] Figure ⅰ corresponds to the cooperative adsorption mechanism of sodium amide and ferric chloride in Example 1. 3+ Coordination is dominant, supplemented by NH2 - Modification enhances surface activity, electrostatic attraction and possible π-π interaction. NaNH2 reacts with FeCl3 to produce NH2 - Modified iron species (such as Fe-NH2), whose surface Fe 3+ with RhB-COO - Coordination, while NH2 - With -OH or -N of RhB + Form hydrogen bonds, Fe 3+ It may bridge multiple RhB molecules to form [Fe(RhB) n ] 3+n- The Fe-NH2 / Fe(OH)3 composite material generated under alkaline conditions significantly improved the adsorption capacity of rhodamine.

[0098] Figure ⅱ corresponds to Example 2, the synergistic adsorption of sodium amide and cobalt chloride. 2+ Coordination is dominant, supplemented by NH2 -Modification enhances surface activity, electrostatic attraction and π-π interaction. NaNH2 hydrolyzes to generate NaOH and NH3, cobalt chloride (CoCl2) generates Co(OH)2 or Co3O4 under alkaline conditions, and NaNH2 reacts with CoCl2 to generate NH2 - Modified cobalt species (such as Co-NH2), whose surface Co 2+ Coordinated with the nitrogen / sulfur atoms of MB, its high specific surface area and surface hydroxyl groups (≡Co-OH) can bind to the -N(CH3)2 of MB through hydrogen bonds. The Co-NH2 / Co3O4 composite material generated under alkaline conditions significantly improves the adsorption capacity of MB.

[0099] Figure ⅲ corresponds to Example 3, the synergistic adsorption of sodium amide and lanthanum chloride with La 3+ Coordination is dominant, supplemented by NH2 - Modification enhances surface activity, electrostatic attraction and π-π interaction. NaNH2 reacts with LaCl3 to produce NH2 - Modified lanthanum species (such as La-NH2), whose surface La 3+ Coordinate with the azo or sulfonic acid group of CR, and NH2 - With CR -NH2 or -SO3 - Congo red (CR) forms hydrogen bonds under alkaline conditions. - ) is completely deprotonated, and the azo bond (—N=N—) may be partially reduced to —NH—NH—, enhancing its affinity with La 3+ The coordination ability of La-NH2 / La(OH)3 composite materials generated under alkaline conditions significantly improves the adsorption capacity of Congo red.

[0100] Figure IV corresponds to the potential mechanism of the synergistic adsorption of tetracycline (TC) by sodium amide (NaNH2) and zinc chloride (ZnCl2) in Example 4. The core of the synergistic effect between the two is dominated by metal ion coordination, supplemented by amino modification to enhance surface activity. NaNH2 reacts with ZnCl2 to produce NH2 - Modified zinc species (such as Zn-NH2), whose surface Zn 2+ Coordinate with -O- or -C=O of TC, and NH2 - It forms hydrogen bonds with the -OH or -NH2 of TC. TC is deprotonated under alkaline conditions (phenolic hydroxyl group -OH→-O-, enol group -C=O→-CO - ), forming a multivalent anion (TC n- ), enhanced with Zn 2+ The coordination ability of TC n- With positively charged ≡Zn-OH2 +The Zn(OH)2 surface localized protonation sites are bound by electrostatic interactions. The Zn-NH2 / Zn(OH)2 or ZnO composites generated under alkaline conditions significantly enhance the adsorption capacity of TC.

[0101] Figure V corresponds to the mechanism of synergistic adsorption of malachite green by sodium amide and barium chloride in Example 5. 2+ Coordination and electrostatic attraction are dominant, supplemented by NH2 - Modification enhances surface activity and hydrogen bonding / π-π interaction. NaNH2 reacts with BaCl2 to produce NH2 - Modified barium species (such as Ba-NH2), whose surface Ba 2+ With MG's-N + (CH3)2 coordination (may actually form outer layer coordination or bridging structure), while NH2 - It forms hydrogen bonds with the benzene ring or -N(CH3)2 of MG to enhance adsorption stability.

[0102] Figure ⅵ corresponds to the mechanism of the synergistic adsorption of reactive black by sodium amide and zirconium chloride in Example 6. 4+ Strong coordination as the core, through NH2 - Modification improves surface activity and combines electrostatic attraction, hydrogen bonding and π-π interaction to achieve efficient adsorption. Reactive black is a sulfonic acid group (-SO3 - ) and anionic dyes with azo bonds (-N=N-), sulfonic acid groups (-SO3 - ) is completely deprotonated, and the azo bond (-N=N-) may be partially reduced to -NH-NH- under strong alkaline conditions, improving the affinity with Zr 4+ NaNH2 reacts with ZrCl4 to produce NH2 - Modified zirconium species (such as Zr-NH2), whose surface Zr 4+ With RB-SO3 - Or -N=N- coordination, while NH2 - It forms hydrogen bonds with the -NH-NH- of RB, promoting adsorption.

[0103] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing ion-functionalized biochar material, characterized in that: The biochar is mixed with sodium amide and subjected to a primary pyrolysis for 5 to 30 minutes in a protective atmosphere at a temperature of 450 to 750° C. to obtain the sodium amide-modified biochar; the sodium amide-modified biochar is mixed with chloride and deionized water for impregnation treatment. After the impregnation is completed, the sodium amide-modified biochar is taken out and subjected to a secondary pyrolysis for 5 to 30 minutes in a protective atmosphere at a temperature of 450 to 750° C. to obtain the ion-functionalized biochar material.

2. The method for preparing an ion-functionalized biochar material according to claim 1, characterized in that: The mass ratio of biochar to sodium amide is 1:1-5.

3. The method for preparing an ion-functionalized biochar material according to claim 1, characterized in that: The impregnation ratio of sodium amide modified biochar to metal ions is 3-20%, and the mass ratio of chloride to deionized water is 0.2-1.5%.

4. The method for preparing an ion-functionalized biochar material according to claim 1, wherein: The chloride is at least one of barium chloride, ferric chloride, ammonium chloride, zinc chloride, lanthanum chloride, and zirconium chloride.

5. The method for preparing an ion-functionalized biochar material according to claim 1, characterized in that: After the biomass charcoal and sodium amide are pyrolyzed once, the biochar is acid-washed with 5-20 wt.% HCl until neutrality is achieved, and the solid matter is separated and dried to obtain sodium amide-modified biochar.

6. The method for preparing an ion-functionalized biochar material according to claim 1, characterized in that: Biochar is produced by primary pyrolysis of biomass raw materials at a temperature of 400 to 800°C for 2 to 40 minutes.

7. The method for preparing an ion-functionalized biochar material according to claim 6, characterized in that: The biomass raw material is at least one of bamboo branches, bamboo leaves and bamboo joints, which is prepared after being washed, dried at a temperature of 80-120 DEG C, crushed and sieved through a 30-140 mesh screen.

8. The ion-functionalized biochar material obtained by the preparation method according to any one of claims 1 to 7.

9. Use of the ion-functionalized biochar material according to claim 8 as a CO2 gas adsorbent, a supercapacitor positive electrode material, a supercapacitor negative electrode material, and an adsorbent for high molecular organic matter in reactive dyes in printing and dyeing wastewater.

10. The use according to claim 9, characterized in that The high molecular organic matter in the reactive dye in the printing and dyeing wastewater is at least one of Congo red, methylene blue, malachite green, tetracycline, rhodamine B or reactive black.

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