A furfural residue derived carbon material with an open pore structure and a preparation method and application thereof

Abstract

The application discloses a furfural residue derived carbon material with an open pore structure and a preparation method and application thereof. The preparation method uses furfural residue and nano-magnesium oxide as raw materials, disperses the two in an aqueous solution through ultrasonic, removes water by heating, and in the process, the nano-magnesium oxide is hydrated to generate small flake diameter magnesium hydroxide nanosheets, meanwhile, the pH of the aqueous solution increases, the furfural residue swells, and through hydrogen bonding, the furfural residue is attached to the surface of the magnesium hydroxide nanosheet, and the nanosheets cross to form an open macroporous structure; then through high-temperature calcination, the magnesium hydroxide is decomposed to generate MgO nanoparticles and water vapor, the water vapor has a gas phase stripping effect, and the MgO is attached to the surface of the furfural residue derived carbon nanosheet, and further dilute acid washing removes the MgO to obtain an open microporous structure. The carbon material has a large number of open pore structures, and in a simulated fixed bed device, as an adsorbent material, the carbon material shows excellent adsorption capacity for macromolecular and small molecular organic pollutants in water.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomass charcoal materials, in particular to a furfural residue derived carbon material with an open pore structure, a preparation method and applications thereof. BACKGROUND

[0002] Industrial and agricultural production wastewater, hospital wastewater, domestic sewage and the like all contain a large amount of organic pollutants, most of which are macromolecular refractory organic matters such as polychlorinated biphenyls and polycyclic aromatic hydrocarbons, which seriously threaten the water ecological environment and human health. The use of adsorption technology can effectively remove organic pollutants in water, without secondary pollution, and is simple to operate and has good practical application prospects. Among them, the preparation of adsorbent materials is an important link in this technology, and the adsorbent not only has excellent adsorption performance, but also has the characteristics of wide raw material sources and low cost.

[0003] Furfural is an important platform compound, which is mainly obtained by acid hydrolysis of hemicellulose in biomass (including corn cob, corn straw, wheat straw, sugarcane residue, waste wood and the like). At present, most of the furfural residue is directly burned as low-energy fuel or discarded, which not only causes a certain burden on the environment, but also causes waste of resources. The main components of furfural residue are cellulose and lignin, and the carbon content is as high as 50%, which is an ideal precursor for preparing carbon materials. Using furfural residue as raw material to prepare porous carbon adsorbent materials and for removing organic pollutants in water can not only realize the high-value application of furfural residue and produce certain economic and social benefits, but also provide a new idea for preparing cheap and easily obtained adsorbent materials.

[0004] Furfural residue has a complex structure, and lignin and cellulose are interwoven together through various connection bonds (ether bond, ester bond, hydrogen bond and the like) to form a complex network structure. If direct pyrolysis carbonization is performed, serious polycondensation will occur, resulting in less pore structure of the obtained carbon material, which limits its application in the adsorption field. At present, there are many studies on preparing carbon adsorbent materials using furfural residue as a precursor, which are mostly focused on the construction of pore structure. Hu Xun et al. studied the influence of different potassium compounds (KCl, KOH, K2CO3 and K2C2O4) on the formation of pores in the process of pyrolysis carbonization of furfural residue, and the results showed that K2CO3 and K2C2O4 had good activation and pore-forming effects, and the specific surface area of the derived carbon could reach more than 1000 m 2 / g. Ma Pengyong et al. prepared furfural residue derived carbon using phosphoric acid as an activation and pore-forming agent, and the specific surface area of the prepared furfural residue derived carbon could reach 1769.4 m 2 / g, and the adsorption capacity of methylene blue could reach 486 mg / g. Han Xiuli et al. prepared furfural residue derived porous carbon by using steam activation to form pores, and the specific surface area of the prepared furfural residue derived porous carbon could reach 1662.41 m 2 / g. Chinese invention patent CN105174254A discloses a method for preparing activated carbon and furfural from corncob. The method comprises the following steps: preparing furfural from corncob by sulfuric acid hydrolysis, and then directly immersing the furfural residue into KOH solution, drying and carbonizing to obtain furfural residue derived porous carbon.

[0005] In summary, there are many methods for preparing furfural residue derived carbon adsorbent materials at present, and the obtained carbon materials have high specific surface area, but the pore structure is complex. The complex pore structure will greatly affect the mass transfer of organic matter in water, increase the mass transfer resistance, especially for macromolecular organic matter in water, such as macromolecular dyes and antibiotics, which is the main reason why the adsorption performance of the current furfural residue derived carbon for macromolecular organic matter is not ideal. On the other hand, in practical application, the adsorbent material is usually filled into a fixed bed device, and then the wastewater containing organic pollutants flows through the fixed bed to remove the pollutants in the water through the adsorption process. The contact time between the adsorbent material and the pollutants is short in this process, and the mass transfer resistance of the adsorbent material has a great influence on the removal effect. SUMMARY

[0006] The purpose of the present application is to solve the problem of complex pore structure of furfural residue derived carbon adsorbent material in the prior art, which leads to unsatisfactory adsorption performance for macromolecular organic matter, and to provide a furfural residue derived carbon material with an open pore structure and a preparation method and application thereof.

[0007] To solve the above technical problems, the technical solution adopted by the present application is: a preparation method of a furfural residue derived carbon material with an open pore structure, comprising the following steps:

[0008] S1. Disperse furfural residue and nano-MgO into an aqueous solution to obtain a mixed solution;

[0009] S2. Remove the water in the mixed solution to obtain a furfural residue / Mg(OH)2 composite;

[0010] S3. Calcine the furfural residue / Mg(OH)2 in an inert gas atmosphere to obtain a carbon / MgO composite;

[0011] S4. Acid wash the carbon / MgO composite to obtain a furfural residue derived carbon material with an open pore structure.

[0012] As a further optimization of the preparation method of the furfural residue derived carbon material with an open pore structure, the method specifically comprises the following steps:

[0013] S1. Add furfural residue and nano-MgO to an aqueous solution, and ultrasonically disperse to obtain a uniformly dispersed mixed solution;

[0014] S2: heating and stirring the mixed solution, stopping stirring when the mixed solution becomes viscous, and obtaining a solid powder of furfural residue / Mg(OH)2 composite through drying;

[0015] S3: calcining the solid powder of furfural residue / Mg(OH)2 composite under an inert gas atmosphere at high temperature to obtain a furfural residue-derived carbon / MgO composite;

[0016] S4: acid washing the carbon / MgO composite with a dilute acid solution, and obtaining a furfural residue-derived carbon material with an open pore structure through filtration, water washing and drying.

[0017] As a further optimization of the preparation method of the furfural residue-derived carbon material with an open pore structure, the mass ratio of furfural residue to nano-MgO in step S1 is 1:0.5-1:5, and the mass concentration of the mixed solution is 50 mg / mL.

[0018] As a further optimization of the preparation method of the furfural residue-derived carbon material with an open pore structure, the temperature of heating and stirring in step S2 is 50-80℃, the stirring rate is 100-500 r / min, and the drying temperature is 90-110℃.

[0019] As a further optimization of the preparation method of the furfural residue-derived carbon material with an open pore structure, the process conditions of calcination in step S3 are as follows: the heating rate is 5-20℃ / min, the temperature is raised to 500-900℃, and the carbonization time is 0.5-5 h.

[0020] As a further optimization of the preparation method of the furfural residue-derived carbon material with an open pore structure, the process conditions of calcination in step S3 are as follows: the heating rate is 8-15℃ / min, the temperature is raised to 600-800℃, and the carbonization time is 1-3 h.

[0021] As a further optimization of the preparation method of the furfural residue-derived carbon material with an open pore structure, the dilute acid solution in step S4 is a nitric acid solution or a hydrochloric acid solution, the concentration of the dilute acid solution is 0.1-2 mol / L, and the drying temperature is 100℃.

[0022] A furfural residue-derived carbon material with an open pore structure is prepared by the above preparation method.

[0023] The furfural residue-derived carbon material with an open pore structure is used for removing small molecule and large molecule organic pollutants in water.

[0024] The present application has the following advantages:

[0025] The furfural residue derived carbon material has macropores formed by the cross of two-dimensional carbon nanosheets and a large number of micropores and mesopores on the carbon nanosheets, the pore channel structure can not only give the material a high specific surface area, but also has the characteristics of openness because the pore channels are exposed to the external environment, as an adsorbent material, the mass transfer resistance of pollutants can be greatly reduced, and the macromolecular organic matter can still exhibit extremely high adsorption capacity in the fixed bed column adsorption, and the application prospect is broad.

[0026] The furfural residue is used as a precursor to prepare the carbon material, the characteristics of the nanometer MgO in the aqueous solution and the hydration of the small flake diameter Mg(OH)2 nanosheet under heating conditions are utilized, the furfural residue derived carbon material with open pore structure is prepared based on the volatile induced self-assembly process, the method is simple and easy to operate, has no corrosiveness to the equipment, and has universality. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The scanning electron microscope graph of the furfural residue derived carbon with open pore structure obtained in Example 1;

[0028] Figure 2 The transmission electron microscope graph of the furfural residue derived carbon with open pore structure obtained in Example 1;

[0029] Figure 3 The nitrogen adsorption-desorption isotherm of the furfural residue derived carbon with open pore structure obtained in Example 1;

[0030] Figure 4 The pore size distribution curve of the furfural residue derived carbon with open pore structure obtained in Example 1;

[0031] Figure 5 The Raman spectrum graph of the furfural residue derived carbon with open pore structure obtained in Example 1;

[0032] Figure 6 The X-ray diffraction graph of the furfural residue derived carbon with open pore structure obtained in Example 1;

[0033] Figure 7 The dynamic column adsorption experiment results of the furfural residue derived carbon with open pore structure obtained in Example 1 on small molecule rhodamine B and macromolecule tylosin. DETAILED DESCRIPTION

[0034] In order to better understand the present application, the content of the present application is further illustrated below in combination with examples, but the content of the present application is not limited to the following examples.

[0035] A preparation method of a furfural residue derived carbon material with open pore structure, specifically comprising the following steps:

[0036] (1) The furfural residue and nano-MgO are added into an aqueous solution according to a mass ratio of 1:0.5-1:5 to configure a mixture aqueous solution with a mass concentration of 50 mg / mL, and ultrasonic dispersion is performed for 5-30 min to obtain a uniformly dispersed mixture aqueous solution.

[0037] In this step, the nano-MgO is not only a pH regulator, but also a structure directing agent and a template agent. If the mass ratio of the furfural residue to the nano-MgO is higher than 2, the pH of the aqueous solution is too low, the furfural residue cannot be well swelled, and the active functional groups are exposed too little, which affects the subsequent self-assembly process. In addition, if the amount of the nano-MgO is too small, the amount of the structure directing agent and the template agent is affected, and thus the improvement of the pore structure and the specific surface area of the carbon material is affected. If the mass ratio of the furfural residue to the nano-MgO is lower than 0.2, the concentration of MgO in the aqueous solution is too high, which leads to the agglomeration of Mg(OH)2 in the hydration process, and is not conducive to the formation of the open macroporous structure.

[0038] In this step, the mass concentration of the mixture aqueous solution is 50 mg / mL. If the concentration is too high, the subsequent volatile-induced self-assembly process is affected. If the concentration is too low, the pH of the aqueous solution is small after the hydration process, which is not conducive to the swelling of the furfural residue and the exposure of the active functional groups.

[0039] (2) The mixture aqueous solution is transferred to a heating stirring table, heated and stirred at 50-80℃, the stirring rate is 100-500 r / min, most of the water is removed by evaporation, the mixture solution becomes viscous, and then the stirring is stopped. Subsequently, the mixture is placed in an oven and dried at 90-110℃ to obtain a furfural residue / Mg(OH)2 composite solid powder.

[0040] In this step, MgO is first hydrated to form Mg(OH)2 in the volatile-induced self-assembly process, which increases the pH of the aqueous solution, swells the furfural residue, and exposes more active functional groups. In addition, the Mg(OH)2 formed by hydration is a small-particle-diameter nanosheet, and the surface contains a large number of hydroxyl groups. As a structure directing agent, the Mg(OH)2 nanosheet is combined with the furfural residue through hydrogen bonding to obtain an open macroporous structure formed by the cross of the nanosheets.

[0041] In this step, the mixture aqueous solution is heated at 50-80℃, so that the nano-MgO can be better hydrated to form small-particle-diameter Mg(OH)2 nanosheets. The increase in the pH of the solution and the generation of the structure directing agent are achieved at the same time. If the heating temperature is lower than 50℃, the nano-MgO is not completely hydrated, which affects the increase in the pH of the solution and the generation of the structure directing agent. If the heating temperature is higher than 80℃, the nano-MgO is hydrated too quickly, and the Mg(OH)2 nanosheets are easily agglomerated, which is not conducive to the generation of the structure directing agent and the subsequent self-assembly process.

[0042] In this step, the stirring rate is controlled at 100-500 r / min, and suitable stirring is conducive to uniform dispersion of the furfural residue and Mg(OH)2 nanosheets, and uniform self-assembly together with the volatilization of water.

[0043] (3) The furfural residue / Mg(OH)2 composite solid powder is transferred into a tube furnace, high-temperature carbonization is carried out under an inert gas atmosphere, the gas flow rate is controlled at 50-100 mL / min, the temperature rising rate is controlled at 8-15 ℃ / min, the temperature is raised to 600-800 ℃, and the carbonization time is 1-3 h. A furfural residue-derived carbon / MgO composite is obtained, and the composite obtained by carbonization is further added to a dilute acid solution with a concentration of 0.1-2 mol / L, stirred for several hours, then filtered, washed with water for multiple times, and dried in an oven at 100 ℃ for 8 h to obtain a furfural residue-derived carbon material with an open pore structure.

[0044] In this step, the furfural residue / Mg(OH)2 composite is calcined, the furfural residue is attached to the Mg(OH)2 nanosheets, a large pore structure of carbon nanosheet intersections is obtained after carbonization, Mg(OH)2 is decomposed to obtain MgO, which is attached to the carbon nanosheets as a hard template, and a large number of open microporous channels are left after acid washing; in addition, the water vapor generated by the decomposition of Mg(OH)2 has the effect of gas phase stripping, preventing the furfural residue from polycondensing during pyrolysis and being conducive to the formation of pores.

[0045] In this step, the carbonization temperature is required to be in the range of 600-800 ℃, and the time is 1-3 h. If the temperature is too low or the time is too short, the furfural residue may not be completely carbonized, and if the temperature is too high or the time is too long, the cost is increased, and more surface functional groups of the carbon material are decomposed, which is not conducive to the adsorption of organic matter.

[0046] In this step, the concentration of the dilute acid solution is required to be in the range of 0.1-2 mol / L, and the acid washing time is controlled to be more than 1 h. If the acid concentration is too low or the time is too short, too much MgO residue will be left, and the pore structure will be less, which is not conducive to the application as an adsorbent, and if the acid concentration is too high, the cost is increased.

[0047] The furfural residue-derived carbon material with an open pore structure prepared by the method of the present application has a specific surface area in the range of 800-1700 m 2 / g, and a wide pore size distribution, with a large number of pores from 0.1 nm to 100 nm, showing an obvious open pore structure formed by the intersection of two-dimensional porous nanosheets.

[0048] The furfural residue-derived carbon material with an open pore structure prepared by the method of the present application can be used to remove organic pollutants in water, especially macromolecular organic pollutants, and also has good adsorption performance.

[0049] MgO is hydrated to Mg(OH)2, which increases the pH of the solution, and the lignin and cellulose in the furfural residue swell, exposing a large number of active functional groups such as methoxyl groups and phenolic hydroxyl groups; the Mg(OH)2 generated by hydration is a small piece of nanosheet, and the surface contains a large number of hydroxyl functional groups, which can form strong hydrogen bonds with the active functional groups in the furfural residue; in the process of water evaporation, the furfural residue is attached to the nanosheet and further cross-linked to form an open macroporous structure; after carbonization, a carbon nanosheet cross-linked pore structure is obtained, and at the same time, the Mg(OH)2 is decomposed into nano-MgO particles and water vapor, which has a gas-phase stripping effect, and the MgO nano-particles are attached to the carbon nanosheet, and after acid washing, a large number of open microporous structures are obtained.

[0050] Example 1

[0051] (1) Take 1.0 g of furfural residue and 5.0 g of nano-MgO, add 120 mL of deionized water, and prepare a mixture aqueous solution, ultrasonic dispersion for 30 min to obtain a uniformly dispersed mixture aqueous solution; further place the mixture aqueous solution on a heating and stirring platform, heat and stir at 80°C, control the stirring rate at 500 r / min, evaporate most of the water, stop stirring when the mixture solution becomes viscous, then put it into an oven and dry at 90°C, grind thoroughly after removing the remaining water to obtain a furfural residue / Mg(OH)2 composite solid powder.

[0052] (2) Place the above furfural residue / Mg(OH)2 composite solid powder in a magnetic boat and transfer it to a tube furnace, and perform high-temperature carbonization under a nitrogen (99.9%) atmosphere, with a gas flow rate of 50 mL / min and a heating rate of 10°C / min, heat to 600°C, and carbonize for 1 h, then cool to room temperature to obtain a furfural residue-derived carbon / MgO composite solid powder.

[0053] (3) Add the above-prepared furfural residue-derived carbon / MgO composite to a 2.0 mol / L dilute hydrochloric acid solution, stir for several hours, then filter, wash with water several times, and dry in an oven at 100°C for 8 h to obtain a furfural residue-derived carbon material with an open pore structure.

[0054] Performance test: take an organic glass column with an inner diameter of 10 mm and a length of 10 cm, fill it with absorbent cotton, 0.1 g of furfural residue-derived carbon, and absorbent cotton in sequence, and connect the two ends of the organic glass column to the outside through rubber plugs connected with plastic tubes, flow a simulated pollutant aqueous solution with a concentration of 150 mg / L into one end, and flow out from the other end, with a flow rate controlled by a peristaltic pump at 2 mL / min. The concentration of the remaining pollutants in the aqueous solution is determined by a UV-visible spectrophotometer, and the adsorption capacity is further calculated.

[0055] Example 2

[0056] (1) Take 1.0 g of furfural residue and 4.0 g of nano-MgO, add 100 mL of deionized water to prepare a mixture aqueous solution, ultrasonic dispersion for 25 min to obtain a uniformly dispersed mixture aqueous solution; further place the mixture aqueous solution on a heating stirring table, heat and stir at 70°C, control the stirring rate at 400 r / min, evaporate most of the water, stop stirring when the mixture solution becomes viscous, then put it into an oven, dry at 100°C, grind thoroughly after removing the remaining water to obtain furfural residue / Mg(OH)2 composite solid powder.

[0057] (2) Place the above furfural residue / Mg(OH)2 composite solid powder in a magnetic boat, transfer it to a tube furnace, and perform high-temperature carbonization under an argon (99.99%) atmosphere, control the gas flow rate at 80 mL / min, control the heating rate at 15°C / min, heat to 700°C, carbonization time is 3h, after carbonization, reduce to room temperature to obtain furfural residue derived carbon / MgO composite solid powder.

[0058] (3) Add the above prepared furfural residue derived carbon / MgO composite to a 1.5 mol / L dilute hydrochloric acid solution, stir for several hours, then filter, wash with water several times, and dry in an oven at 100°C for 8h to obtain a furfural residue derived carbon material with open pore structure.

[0059] Performance test: take an organic glass column with an inner diameter of 10 mm and a length of 10 cm, fill it with degreasing cotton, 0.1 g of furfural residue derived carbon and degreasing cotton in turn, connect the two ends of the organic glass column with plastic tubes through rubber plugs to communicate with the outside world, pour a simulated pollutant aqueous solution with a concentration of 150 mg / L into one end, and let it flow out from the other end, control the flow rate at 2 mL / min by peristaltic pump. Determine the concentration of the remaining pollutants in the aqueous solution by ultraviolet-visible spectrophotometer, and further calculate the adsorption capacity.

[0060] Example 3

[0061] (1) Take 1.0 g of furfural residue and 3.0 g of nano-MgO, add 80 mL of deionized water to prepare a mixture aqueous solution, ultrasonic dispersion for 20 min to obtain a uniformly dispersed mixture aqueous solution; further place the mixture aqueous solution on a heating stirring table, heat and stir at 60°C, control the stirring rate at 300 r / min, evaporate most of the water, stop stirring when the mixture solution becomes viscous, then put it into an oven, dry at 110°C, grind thoroughly after removing the remaining water to obtain furfural residue / Mg(OH)2 composite solid powder.

[0062] (2) The above furfural residue / Mg(OH)2 composite solid powder was placed in a magnetic boat and transferred to a tube furnace for high-temperature carbonization under an argon (99.99%) atmosphere, with a gas flow rate controlled at 90 mL / min and a heating rate controlled at 20°C / min. The temperature was raised to 750°C, and the carbonization time was 2.5 h. After carbonization, the temperature was lowered to room temperature to obtain furfural residue-derived carbon / MgO composite solid powder.

[0063] (3) The above prepared furfural residue-derived carbon / MgO composite was added to a 1.0 mol / L dilute hydrochloric acid solution, stirred for several hours, then filtered, washed with water several times, and dried in an oven at 100°C for 8 h to obtain a furfural residue-derived carbon material with an open pore structure.

[0064] Performance test: An organic glass column with an inner diameter of 10 mm and a length of 10 cm was filled with degreasing cotton, 0.1 g of furfural residue-derived carbon, and degreasing cotton in sequence. The organic glass column was connected to the outside through rubber plugs with plastic tubes at both ends. A simulated pollutant aqueous solution with a concentration of 150 mg / L flowed in from one end, and flowed out from the other end, with a flow rate controlled at 2 mL / min by a peristaltic pump. The concentration of the remaining pollutants in the aqueous solution was measured by a UV-visible spectrophotometer, and the adsorption capacity was further calculated.

[0065] Example 4

[0066] (1) 1.0 g of furfural residue and 2.0 g of nano-MgO were added to 60 mL of deionized water to prepare a mixture aqueous solution, which was ultrasonically dispersed for 20 min to obtain a uniformly dispersed mixture aqueous solution. The mixture aqueous solution was further placed on a heating and stirring platform and heated and stirred at 65°C with a stirring rate controlled at 300 r / min. Most of the water was evaporated, and the mixture solution became viscous. The stirring was stopped, and then the mixture was placed in an oven and dried at 100°C. After the remaining water was removed, the mixture was thoroughly ground to obtain a furfural residue / Mg(OH)2 composite solid powder.

[0067] (2) The above furfural residue / Mg(OH)2 composite solid powder was placed in a magnetic boat and transferred to a tube furnace for high-temperature carbonization under a nitrogen (99.9%) atmosphere, with a gas flow rate controlled at 100 mL / min and a heating rate controlled at 15°C / min. The temperature was raised to 800°C, and the carbonization time was 2.0 h. After carbonization, the temperature was lowered to room temperature to obtain furfural residue-derived carbon / MgO composite solid powder.

[0068] (3) The above prepared furfural residue-derived carbon / MgO composite was added to a 1.5 mol / L dilute nitric acid solution, stirred for several hours, then filtered, washed with water several times, and dried in an oven at 100°C for 8 h to obtain a furfural residue-derived carbon material with an open pore structure.

[0069] Performance test: take a 10 mm inner diameter, length of 10 cm organic glass column, filled with cotton, 0.1 g of furfural residue derived carbon and cotton, organic glass column through the rubber plug with plastic tube connected with the outside world, concentration of 150 mg / L of simulated pollutants aqueous solution from one end, the other end out, flow rate by peristaltic pump control at 2 mL / min. Determined by UV-visible spectrophotometer to determine the concentration of the remaining pollutants in aqueous solution, and further calculate the adsorption capacity.

[0070] Example 5

[0071] (1) take 1.0 g of furfural residue and 1.0 g of nano-MgO, add 40 mL of deionized water, configure into a mixture aqueous solution, ultrasonic dispersion for 15 min, get a uniform dispersion of the mixture aqueous solution; further the mixture aqueous solution is placed on a heating and stirring platform, heated and stirred at 50℃, the stirring rate is controlled at 200 r / min, most of the water is removed by evaporation, when the mixture solution becomes viscous, stop stirring, then put into the oven, dry at 110℃, after removing the remaining water, grind thoroughly, get furfural residue / Mg(OH)2 composite solid powder.

[0072] (2) the above furfural residue / Mg(OH)2 composite solid powder is placed in a magnetic boat and transferred to a tube furnace for high-temperature carbonization under nitrogen (99.9%) atmosphere, the gas flow rate is controlled at 80 mL / min, the heating rate is controlled at 10℃ / min, the temperature is raised to 600℃, and the carbonization time is 3.0 h, then the temperature is lowered to room temperature, to obtain furfural residue derived carbon / MgO composite solid powder.

[0073] (3) the above prepared furfural residue derived carbon / MgO composite is added to a 0.5 mol / L dilute nitric acid solution, stirred for several hours, then filtered, washed with water several times, and dried in an oven at 100℃ for 8 h, to obtain furfural residue derived carbon material with open pore structure.

[0074] Performance test: take a 10 mm inner diameter, length of 10 cm organic glass column, filled with cotton, 0.1 g of furfural residue derived carbon and cotton, organic glass column through the rubber plug with plastic tube connected with the outside world, concentration of 150 mg / L of simulated pollutants aqueous solution from one end, the other end out, flow rate by peristaltic pump control at 2 mL / min. Determined by UV-visible spectrophotometer to determine the concentration of the remaining pollutants in aqueous solution, and further calculate the adsorption capacity.

[0075] Comparative example 1

[0076] The adsorption performance of commercially purchased coconut shell activated carbon as adsorbent material is tested.

[0077] Performance test: take a organic glass column with inner diameter of 10 mm and length of 10 cm, fill in the degreasing cotton, 0.1 g of commercial activated carbon and degreasing cotton in turn, the organic glass column is connected with the outside through the rubber plug with plastic tube at both ends, the simulated pollutant aqueous solution with concentration of 150 mg / L flows into one end, and flows out from the other end, the flow rate is controlled at 2 mL / min by peristaltic pump. The concentration of residual pollutants in the aqueous solution is determined by ultraviolet visible spectrophotometer, and the adsorption capacity is further calculated.

[0078] Comparative example 2

[0079] (1) Take 1.0 g of furfural residue and 1.0 g of potassium hydroxide, add 50 mL of deionized water to prepare a mixture aqueous solution, ultrasonic dispersion for 20 min to obtain a uniformly dispersed mixture aqueous solution; further place the mixture aqueous solution on a heating stirring table, heat and stir at 70℃, the stirring rate is controlled at 200 r / min, evaporate most of the water, stop stirring when the mixture solution becomes viscous, then put it into an oven and dry at 100℃, after removing the remaining water, grind thoroughly to obtain a furfural residue / KOH composite solid powder.

[0080] (2) Place the above furfural residue / KOH composite solid powder in a magnetic boat and transfer it to a tube furnace, carbonize under nitrogen (99.9%) atmosphere, the gas flow rate is controlled at 80 mL / min, the heating rate is controlled at 10℃ / min, heat to 800℃, the carbonization time is 2 h, after carbonization, cool to room temperature to obtain a composite solid powder; further add the above prepared solid powder to a dilute hydrochloric acid solution with a concentration of 1.0 mol / L, stir for several hours, then filter, wash with water several times, and put it into an oven and dry at 100℃ for 8 h to obtain a furfural residue derived porous carbon material.

[0081] Performance test: take a organic glass column with inner diameter of 10 mm and length of 10 cm, fill in the degreasing cotton, 0.1 g of commercial activated carbon and degreasing cotton in turn, the organic glass column is connected with the outside through the rubber plug with plastic tube at both ends, the simulated pollutant aqueous solution with concentration of 150 mg / L flows into one end, and flows out from the other end, the flow rate is controlled at 2 mL / min by peristaltic pump. The concentration of residual pollutants in the aqueous solution is determined by ultraviolet visible spectrophotometer, and the adsorption capacity is further calculated.

[0082] Comparative example 3

[0083] (1) Take 1.0 g of furfural residue and 1.0 g of zinc chloride, add 50 mL of deionized water to prepare a mixture aqueous solution, ultrasonic dispersion for 20 min to obtain a uniformly dispersed mixture aqueous solution; further place the mixture aqueous solution on a heating stirring table, heat and stir at 80°C, control the stirring rate at 200 r / min, evaporate most of the water, stop stirring when the mixture solution becomes viscous, then put it into an oven, dry at 100°C, grind thoroughly after removing the remaining water to obtain a furfural residue / ZnCl2 composite solid powder.

[0084] (2) Place the above furfural residue / ZnCl2 composite solid powder in a magnetic boat, transfer it to a tube furnace, and perform high-temperature carbonization under an argon (99.99%) atmosphere, with a gas flow rate of 60 mL / min and a heating rate of 15°C / min, heat to 600°C, and carbonize for 2 h, then cool to room temperature to obtain a composite solid powder; further add the above prepared solid powder to a 2.0 mol / L dilute hydrochloric acid solution, stir for several hours, then filter, wash with water several times, and dry in an oven at 100°C for 8 h to obtain a furfural residue-derived porous carbon material.

[0085] Performance test: Take an organic glass column with an inner diameter of 10 mm and a length of 10 cm, fill it with degreasing cotton, 0.1 g of furfural residue-derived carbon, and degreasing cotton in sequence, connect the two ends of the organic glass column to the outside through rubber plugs with plastic tubes, flow a simulated pollutant aqueous solution with a concentration of 150 mg / L into one end, and flow out from the other end, control the flow rate by a peristaltic pump at 2 mL / min. Use a UV-visible spectrophotometer to measure the concentration of the remaining pollutants in the aqueous solution, and further calculate the adsorption capacity.

[0086] Comparative Example 4

[0087] (1) Take 1.0 g of furfural residue and 2.0 g of nano-silicon dioxide, add 50 mL of deionized water to prepare a mixture aqueous solution, ultrasonic dispersion for 30 min to obtain a uniformly dispersed mixture aqueous solution; further place the mixture aqueous solution on a heating stirring table, heat and stir at 90°C, control the stirring rate at 300 r / min, evaporate most of the water, stop stirring when the mixture solution becomes viscous, then put it into an oven, dry at 100°C, grind thoroughly after removing the remaining water to obtain a furfural residue / SiO2 composite solid powder.

[0088] (2) The above furfural residue / SiO2 composite solid powder is placed in a magnetic boat and transferred to a tube furnace for high-temperature carbonization under a nitrogen (99.9%) atmosphere, with a gas flow rate controlled at 80 mL / min and a heating rate controlled at 15°C / min. The temperature is raised to 700°C, and the carbonization time is 2 h. After carbonization, the temperature is lowered to room temperature to obtain a composite solid powder. The above prepared solid powder is further added to a 2.0 mol / L hydrofluoric acid solution, stirred for several hours, then filtered, washed with water multiple times, and placed in an oven at 100°C for drying for 8 h to obtain a furfural residue-derived porous carbon material.

[0089] Performance test: Take an organic glass column with an inner diameter of 10 mm and a length of 10 cm, and fill it with degreasing cotton, 0.1 g of furfural residue-derived carbon, and degreasing cotton in sequence. The organic glass column is connected to the outside through rubber plugs with plastic tubes at both ends. A simulated pollutant aqueous solution with a concentration of 150 mg / L is flowed into one end, and the other end is flowed out, with the flow rate controlled at 2 mL / min by a peristaltic pump. The concentration of the remaining pollutants in the aqueous solution is measured by a UV-visible spectrophotometer, and the adsorption capacity is further calculated.

[0090] Comparative Example 5

[0091] (1) Take 1.0 g of phenol and 5.0 g of nano-MgO, add 120 mL of deionized water to prepare a mixture aqueous solution, and ultrasonic disperse for 30 min to obtain a uniformly dispersed mixture aqueous solution. Further, the mixture aqueous solution is placed on a heating stirring table and heated and stirred at 70°C, with a stirring rate controlled at 400 r / min. Most of the water is evaporated, and the mixture solution becomes viscous. The stirring is stopped, and then the mixture is placed in an oven and dried at 90°C. After the remaining water is removed, the mixture is thoroughly ground to obtain a phenol / Mg(OH)2 composite solid powder.

[0092] (2) The above phenol / Mg(OH)2 composite solid powder is placed in a magnetic boat and transferred to a tube furnace for high-temperature carbonization under a nitrogen (99.9%) atmosphere, with a gas flow rate controlled at 30 mL / min and a heating rate controlled at 15°C / min. The temperature is raised to 600°C, and the carbonization time is 2 h. After carbonization, the temperature is lowered to room temperature to obtain a composite solid powder. The above prepared solid powder is further added to a 2.0 mol / L dilute hydrochloric acid solution, stirred for several hours, then filtered, washed with water multiple times, and placed in an oven at 100°C for drying for 8 h to obtain a phenol-derived porous carbon material.

[0093] Performance test: take a 10mm inner diameter, length 10cm organic glass column, filled with cotton, 0.1g phenol derived carbon and cotton, organic glass column through the rubber plug connected with plastic tube and the outside communication, concentration of 150mg / L of simulated pollutants aqueous solution from one end into, the other end out, flow rate by peristaltic pump control at 2mL / min. The concentration of the remaining pollutants in the aqueous solution was determined by UV-visible spectrophotometer, and the adsorption capacity was further calculated.

[0094] Comparative example 6

[0095] (1) 1.0g chitosan and 4.0g nano MgO were taken and added into 100ml deionized water to prepare a mixture aqueous solution, which was ultrasonically dispersed for 30min to obtain a uniformly dispersed mixture aqueous solution; further, the mixture aqueous solution was placed on a heating stirring table, heated and stirred at 70℃, the stirring rate was controlled at 400r / min, most of the water was removed by evaporation, and when the mixture solution became viscous, the stirring was stopped, then it was placed in an oven and dried at 90℃, after the remaining water was removed, it was fully ground to obtain a chitosan / Mg(OH)2 composite solid powder.

[0096] (2) the above chitosan / Mg(OH)2 composite solid powder was placed in a magnetic boat and transferred to a tube furnace, and high-temperature carbonization was carried out under argon (99.99%) atmosphere, the gas flow rate was controlled at 30mL / min, the heating rate was controlled at 15℃ / min, the temperature was raised to 600℃, and the carbonization time was 2h, then the temperature was lowered to room temperature to obtain a composite solid powder; further, the above prepared solid powder was added into a 2.0mol / L dilute hydrochloric acid solution, stirred for several hours, then filtered, washed with water for several times, placed in an oven and dried at 100℃ for 8h to obtain a chitosan derived porous carbon material.

[0097] Performance test: take a 10mm inner diameter, length 10cm organic glass column, filled with cotton, 0.1g chitosan derived carbon and cotton, organic glass column through the rubber plug connected with plastic tube and the outside communication, concentration of 150mg / L of simulated pollutants aqueous solution from one end into, the other end out, flow rate by peristaltic pump control at 2mL / min. The concentration of the remaining pollutants in the aqueous solution was determined by UV-visible spectrophotometer, and the adsorption capacity was further calculated.

[0098] <adsorption performance comparison>

[0099] The implementation effect is explained: table 1 is the adsorption performance evaluation data of rhodamine B and tylosin of the examples and comparative examples of the application.

[0100]

[0101] As can be seen from the data of Examples 1-5 and Comparative Example 1 in Table 1, in the simulated fixed bed adsorption experiment, the furfural residue derived carbon with open pore structure prepared in the examples of the present application has better adsorption performance on rhodamine B and tylosin than the commercial activated carbon. Especially for the macromolecular pollutant tylosin, the adsorption capacity of the furfural residue derived carbon obtained in Example 1 is 10 times that of the carbon material in Comparative Example 1. This is because the furfural residue derived carbon obtained in the examples has an open porous structure, which can not only give the carbon material a high specific surface area to provide a large number of adsorption sites, but also facilitate mass transfer. The specific surface area of the commercial activated carbon is small, and the pore channel is complex, which is not conducive to the adsorption of organic matter in water, especially macromolecular organic matter.

[0102] As can be seen from the data of Examples 1-5 and Comparative Examples 2 and 3 in Table 1, in the simulated fixed bed adsorption experiment, the furfural residue derived carbon with open pore structure prepared in the examples of the present application has better adsorption performance on rhodamine B and tylosin than the common furfural residue derived porous carbon prepared by KOH and zinc chloride activation method. This is because the furfural residue derived carbon prepared by the common activation method is mainly microporous. Although it has a high specific surface area and can provide adsorption sites, the mass transfer resistance is large compared with the furfural residue derived carbon with open pore structure.

[0103] As can be seen from the data of Examples 1-5 and Comparative Example 4 in Table 1, in the simulated fixed bed adsorption experiment, the furfural residue derived carbon with open pore structure prepared in the examples of the present application has better adsorption performance on rhodamine B and tylosin than the furfural residue derived mesoporous carbon prepared by hard template method. This is because the furfural residue derived carbon prepared by the hard template method is mainly uniform mesoporous. The single mesoporous structure cannot provide a high specific surface area, resulting in insufficient adsorption sites, and part of the pore structure is embedded in the material, which has a large mass transfer resistance.

[0104] As can be seen from the data of Examples 1-5 and Comparative Examples 5 and 6 in Table 1, in the simulated fixed bed adsorption experiment, the furfural residue derived carbon with open pore structure prepared in the examples of the present application has better adsorption performance on rhodamine B and tylosin than the porous carbon prepared by using phenol and chitosan as carbon source. This is because the lignin and cellulose in the furfural residue are intertwined to form a three-dimensional network structure. During the hydration of nanometer magnesium oxide, the swelling occurs with the increase of pH, which exposes a large number of hydroxyl functional groups, and further self-assembles with the magnesium hydroxide nanosheets obtained by hydration, and the open porous structure is obtained after carbonization and washing away the template. Phenol and chitosan do not have such structural characteristics and cannot form similar open porous structure.

[0105] The specific embodiments of the present application are described above. It needs to be understood that the present application is not limited to the specific embodiments described above, and various modifications or changes can be made by those skilled in the art within the scope of the claims, which do not affect the essence of the present application.

Claims

1. A process for the preparation of a furfural residue derived carbon material having an open pore structure, characterized by: Specifically comprising the following steps: S1: adding furfural residue and nano-MgO into an aqueous solution, and obtaining a uniformly dispersed mixture after ultrasonic dispersion, wherein the mass ratio of furfural residue to nano-MgO is 1:0.5-1:5, and the total mass concentration of furfural residue and nano-MgO in the mixture is 50 mg / mL; S2: heating and stirring the mixture, stopping stirring when the mixture becomes viscous, and obtaining a furfural residue / Mg(OH)2 composite solid powder after drying; wherein Mg(OH)2 is a nanosheet, the heating and stirring temperature is 50-80℃, the stirring rate is 100-500 r / min, and the drying temperature is 90-110℃; S3: high-temperature calcining the furfural residue / Mg(OH)2 composite solid powder in an inert gas atmosphere to obtain a furfural residue-derived carbon / MgO composite; the calcining process conditions are: a heating rate of 5-20℃ / min, heating to 500-900℃, and a carbonization time of 0.5-5 h; S4: acid washing the carbon / MgO composite with a dilute acid solution, and then filtering, washing with water, and drying to obtain a furfural residue-derived carbon material with an open pore structure.

2. The process for the preparation of furfural residue derived carbon material with open pore structure as claimed in claim 1 wherein: The calcining process conditions in step S3 are: a heating rate of 8-15℃ / min, heating to 600-800℃, and a carbonization time of 1-3 h.

3. The process for the preparation of furfural residue derived carbon material with open pore structure as claimed in claim 1 wherein: The dilute acid solution in step S4 is a nitric acid solution or a hydrochloric acid solution, the concentration of the dilute acid solution is 0.1-2 mol / L, and the drying temperature is 100℃.

4. A furfural residue derived carbon material having an open pore structure, characterized by: Prepared by the preparation method of any one of claims 1-3.

5. The application of the furfural residue-derived carbon material of claim 4 in removing small molecule and large molecule organic pollutants in water.

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