CN115634679A - Chitosan-based biochar with porous structure and high specific surface area, and preparation method and application thereof - Google Patents
Chitosan-based biochar with porous structure and high specific surface area, and preparation method and application thereof Download PDFInfo
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- JRKICGRDRMAZLK-UHFFFAOYSA-L peroxydisulfate Chemical compound [O-]S(=O)(=O)OOS([O-])(=O)=O JRKICGRDRMAZLK-UHFFFAOYSA-L 0.000 claims abstract description 39
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- XMEVHPAGJVLHIG-FMZCEJRJSA-N chembl454950 Chemical compound [Cl-].C1=CC=C2[C@](O)(C)[C@H]3C[C@H]4[C@H]([NH+](C)C)C(O)=C(C(N)=O)C(=O)[C@@]4(O)C(O)=C3C(=O)C2=C1O XMEVHPAGJVLHIG-FMZCEJRJSA-N 0.000 claims description 2
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Images
Abstract
The invention discloses chitosan-based biochar with a porous structure and a high specific surface area, and a preparation method and application thereof, wherein the method comprises the following steps: firstly preparing chitosan hydrogel and chitosan aerogel, then heating the chitosan aerogel to 600-650 ℃ for calcining, washing, and then heating to 800-850 ℃ for calcining to obtain the chitosan-based biochar with a porous structure and a high specific surface area. The chitosan-based biochar prepared by the invention contains a large number of micropores, mesopores and macropores, has the advantages of high specific surface area, rich pore structure, good catalytic performance, strong anti-interference performance, environmental protection and the like, can be used for activating persulfate to degrade organic pollutants in water, shows excellent removal effect and high-efficiency removal efficiency, and has good application prospect. The preparation method has the advantages of simple process, low cost, no secondary pollution and the like, is suitable for large-scale preparation, and is beneficial to industrial application.
Description
Technical Field
The invention belongs to the technical field of catalytic materials, and particularly relates to chitosan-based biochar with a porous structure and a high specific surface area, and a preparation method and application thereof.
Background
Organic pollutants such as phenolic pollutants, antibiotics, dyes and the like are detected in a large amount in water environment, and pose threats to the ecological environment and human health. Advanced oxidation technologies based on catalysts to activate persulfate have shown great application prospects in water pollution remediation, where the properties of the catalyst are key factors influencing the technical effect. Biochar is a new type of carbon catalyst which has emerged in recent years and has the following advantages: (1) the price is low, the preparation method is simple, and the resource utilization and carbonization reduction of wastes can be realized; (2) the environment is friendly, no secondary pollution risk exists, and the method can be popularized and applied in a large area; (3) the pore structure is rich and adjustable, and the specific surface area is larger; (4) the surface oxygen-containing functional group and carbon configuration are rich, and the functional modification is easy to realize. In the practical application process, when the biochar is used for activating the persulfate to treat the organic pollutant water body, a good removing effect and practical application advantages are shown, namely, the biochar can achieve the effect comparable to that of graphene and a metal catalyst. However, in the practical application process, due to the limitation of the physical and chemical properties of biomass, the preparation method and the regulation method of the biochar are not highly targeted, so that the catalytic activation effect of the biochar catalyst is limited, the removal effect and the removal efficiency of organic pollutants are not ideal, and the treatment time is too long. Therefore, how to select a proper biomass material and adopt a proper method to prepare the biochar catalyst with high catalytic performance is very important for the practical application of a biochar-persulfate system. In addition, the advanced oxidation technology based on the activation of persulfate by the biochar catalyst is easily interfered by organic matters, common anions, halogen ions and other substances in a water treatment system, so that the removal effect of organic pollutants is greatly reduced. In addition, in the practical research process of the inventor of the application, the defects of small specific surface area, single pore structure, poor catalytic performance and the like of the existing chitosan-based biochar are also found, so that the chitosan-based biochar is difficult to effectively and quickly remove organic pollutants in water. Therefore, the obtained chitosan-based biochar catalyst has the advantages of high specific surface area, rich pore structure, good catalytic performance, strong anti-interference performance, greenness and environmental protection, and has very important significance for effectively activating persulfate and realizing efficient degradation of organic pollutants.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide the chitosan-based biochar which has the advantages of high specific surface area, rich pore structure, good catalytic performance, strong anti-interference performance, green and environment-friendly porous structure and high specific surface area, and the preparation method and the application thereof.
In order to solve the technical problems, the invention adopts the following technical scheme.
A preparation method of chitosan-based biochar with a porous structure and a high specific surface area comprises the following steps:
s1, dissolving chitosan in an alkaline solution to obtain a chitosan solution, performing freezing-unfreezing circulation treatment on the chitosan solution, stirring, and drying to obtain chitosan hydrogel; the alkaline solution is a mixed solution containing potassium hydroxide and a nitrogen source;
s2, carrying out freeze drying treatment on the chitosan hydrogel obtained in the S1 to obtain chitosan aerogel;
s3, heating the chitosan aerogel obtained in the S2 to 600-650 ℃, calcining, washing and drying;
and S4, heating the product obtained after drying in the S3 to 800-850 ℃ for calcining to obtain the chitosan-based biochar with a porous structure and a high specific surface area.
In the above method, it is further preferable that in S1, the alkaline solution is prepared by dissolving potassium hydroxide and a nitrogen source into a solvent, the mass ratio of the chitosan, the potassium hydroxide, the nitrogen source and the solvent is 4-5: 11-12: 7-8: 77-80, and the nitrogen source is at least one of urea, cyanamide and melamine; the solvent is water.
In the method, it is further preferable that in S1, the freezing-thawing cycle processing is to sequentially freeze and thaw the chitosan solution, and the freezing and thawing processing is repeated for a number of cycles of not less than 3; the freezing treatment is carried out at the temperature of-20 ℃ to-40 ℃; the time of single freezing treatment is 12-24 h; the unfreezing treatment is carried out at the temperature of 4-6 ℃; the time of single unfreezing treatment is 12-24 h.
In the above method, it is further preferable that in S3, the calcination is performed in an inert atmosphere, the inert atmosphere is nitrogen, the temperature rise rate in the calcination process is 5 ℃/min to 10 ℃/min, and the calcination time is 2h to 2.5h.
In the above method, it is further preferable that, in S4, the calcination is performed in an inert atmosphere, the inert atmosphere is nitrogen, the temperature rise rate in the calcination process is 5 ℃/min to 10 ℃/min, and the calcination time is 2h to 2.5h.
In the method, it is further preferable that in S1, the stirring is performed at 0 ℃, the stirring time is 2h to 3h, the drying is performed under a vacuum condition, the drying temperature is 15 ℃ to 35 ℃, and the drying time is 4h to 6h.
In the above method, it is further preferable that in S2, the freeze-drying is performed under vacuum.
In the above method, it is further preferable that in S3, the drying temperature is 80 to 120 ℃, and the drying time is 6 to 10 hours.
As a general inventive concept, the present invention also provides a chitosan-based biochar having a porous structure and a high specific surface area, which is prepared by the above-described preparation method.
In the chitosan-based biochar with the porous structure and the high specific surface area, it is further preferable that the chitosan-based biochar comprises three pore structures of micro pores, meso pores and macro pores, and the BET specific surface area of the chitosan-based biochar is 1600m 2 /g～2400m 2 Per g, the pore volume of the chitosan-based biochar is 0.8cm 3 /g～1.2cm 3 /g。
The present invention also provides, as a general inventive concept, an application of the chitosan-based biochar having a porous structure and a high specific surface area described above in treating organic pollutant wastewater.
The above application, further preferably, comprises the steps of: mixing chitosan-based biochar with a porous structure and a high specific surface area, persulfate and the water containing organic pollutants, and carrying out degradation reaction to finish the degradation of the organic pollutants in the water.
In the above application, it is further preferable that the addition amount of the chitosan-based biochar is 0.05g to 0.125g of chitosan-based biochar added to each liter of water containing organic pollutants, the addition amount of the persulfate is 0.15mmol to 0.75mmol added to each liter of water containing organic pollutants, the persulfate is sodium persulfate, the initial concentration of the organic pollutants in the water containing organic pollutants is 50mg/L to 100mg/L, the initial pH value of the water containing organic pollutants is 3 to 11, the organic pollutants in the water containing organic pollutants include at least one of a phenolic compound, a dye and an antibiotic, the phenolic compound is at least one of 2, 4-dichlorophen and phenol, the dye is at least one of methyl orange and methylene blue, the antibiotic is at least one of oxytetracycline and tetracycline hydrochloride, the degradation reaction is performed under an oscillation condition, the rotation speed of the oscillation is 120r/min to 200r/min, the degradation reaction temperature is 15 ℃ to 35 ℃, and the degradation reaction time is 5min to 60min.
Compared with the prior art, the invention has the advantages that:
(1) Aiming at the defects of small specific surface area, small number of active sites, low catalytic activity, poor removal effect on organic pollution, slow mass transfer, low removal efficiency and the like of the existing charcoal catalyst, the invention provides a preparation method of chitosan-based charcoal with a porous structure and high specific surface area, which takes chitosan as a raw material, firstly dissolves the chitosan into a mixed solution (alkaline solution) containing potassium hydroxide and a nitrogen source, continuously shrinks and swells the chitosan through freezing-unfreezing circulation treatment to coat the potassium hydroxide and the nitrogen source into the chitosan, forms a chitosan gel solution in the stirring process, further removes a small amount of bubbles in the drying process and generates chemical crosslinking reaction to form chitosan hydrogel coated with the potassium hydroxide and the nitrogen source, and then carries out freeze drying treatment on the chitosan hydrogel, in the freeze drying process, solvent (such as water) molecules in the chitosan hydrogel are directly gasified and removed to form loose and porous chitosan aerogel, which is beneficial to the formation of a porous structure in the subsequent calcining process, particularly the formation of a macroporous structure, and finally, the loose and porous chitosan aerogel is sequentially calcined at the temperature of 600-650 ℃ and the temperature of 800-850 ℃ for two times, wherein the calcining is firstly carried out at the temperature of 600-650 ℃, the chitosan can be converted into a carbon material on the premise of keeping the original structure, and in the process, potassium hydroxide is used as a pore-forming agent and a solvent, so that the formation of the porous structure can be further promoted, and nitrogen elements can be doped into biological carbon, thereby being more beneficial to the formation of the porous structure containing a large number of mesopores, mesopores and macropores, the chitosan-based biochar has higher specific surface area, more active sites and better catalytic activity, and meanwhile, after the calcining is finished at the temperature of 600-650 ℃, residual impurities (including K) in the biochar are cleaned 2 CO 3 、K 2 O, KOH, etc.),the original porous structure of the biochar can not be damaged in the subsequent calcining process at 800-850 ℃, and the graphitization degree of the biochar can be further improved, so that the biochar has more excellent catalytic activity. Compared with the chitosan-based biochar prepared by the conventional method, the chitosan-based biochar prepared by the preparation method disclosed by the invention comprises a large number of micropores, mesopores and macropores, wherein the proportion of the mesopores (2-50 nm) is the largest, the pore structure is rich, the specific surface area and the number of active sites of the chitosan-based biochar can be obviously improved, the transfer of substances in a catalytic degradation system can be accelerated, and meanwhile, the graphitization degree of the chitosan-based biochar is higher, so that the rapid degradation of organic pollutants can be realized, the high-efficiency activation of persulfate can also be realized, and the chitosan-based biochar has the advantages of high specific surface area, rich pore structure, good catalytic performance, strong anti-interference performance, environmental friendliness and the like, can be used for activating the persulfate to degrade the organic pollutants in a water body, and shows excellent removal effect and high removal efficiency, and has a good application prospect. In addition, the preparation method has the advantages of simple process, low cost, no secondary pollution and the like, is suitable for large-scale preparation, and is beneficial to industrial application.
(2) According to the preparation method, the mass ratio of the chitosan to the potassium hydroxide to the nitrogen source to the solvent (such as water) is optimized to be 4-5: 11-12: 7-8: 77-80, so that the chitosan can be rapidly dissolved in a framework, more holes can be formed, the pore structure of the chitosan-based biochar can be optimized, a higher specific surface area can be obtained, and organic pollutants in a water body can be rapidly degraded by the chitosan-based biochar. In addition, the potassium hydroxide used in the present invention is used as both a solvent and a pore-forming agent, and cannot be replaced by other conventional pore-forming agents (such as zinc chloride and phosphoric acid), and substances with high nitrogen content, such as urea, cyanamide, melamine, etc., can be used as a nitrogen source, but considering the factors of cost, environmental friendliness, etc., urea is an optimal nitrogen source because it is water-soluble, cheap, and non-toxic.
(3) The invention also provides application of the chitosan-based biochar with the porous structure and the high specific surface area in treating organic pollutants, the degradation of the organic pollutants in the water body can be realized by mixing the chitosan-based biochar with the porous structure and the high specific surface area, persulfate and the water body containing the organic pollutants for degradation reaction, and the chitosan-based biochar has the advantages of simple process, convenience in operation, low treatment cost, high treatment efficiency, good removal effect and the like, and has important significance for effectively removing the organic pollutants in the water body and realizing effective treatment of the polluted water body. According to the invention, when chitosan-based biochar activated persulfate with a porous structure and a high specific surface area is used for degrading organic pollutants, the organic pollutants are efficiently degraded through a non-free radical path, and in the degradation process, no sulfate radical and hydroxyl radical are generated, and the existence of singlet oxygen is not detected, so that the constructed catalytic system has good anti-interference performance, the catalytic degradation reaction process is hardly influenced by the change of pH value, common anions and natural organic matters in a water body have little influence on the degradation effect, and the method has the advantage of wide application range. By taking 2, 4-dichlorophen and methyl orange as examples, when the chitosan-based biochar with a porous structure and a high specific surface area is adopted to activate persulfate so as to degrade organic pollutants, the removal rate can reach over 90 percent in 5min of reaction, and the chitosan-based biochar has a good removal effect on the 2, 4-dichlorophen in a water body within the range of pH value of 3-11, so that the chitosan-based biochar has a good practical application prospect.
Drawings
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.
Fig. 1 is SEM and TEM images of chitosan-based biochar having a porous structure and a high specific surface area, which was prepared in example 1 of the present invention.
FIG. 2 is a graph showing adsorption and desorption of chitosan-based biochar (BC-800) having a porous structure and a high specific surface area obtained in example 1 of the present invention and chitosan-based biochar (BC-700) obtained in comparative example 1.
FIG. 3 is a pore size distribution diagram of chitosan-based biochar (BC-800) having a porous structure and a high specific surface area obtained in example 1 of the present invention and chitosan-based biochar (BC-700) obtained in comparative example 1.
FIG. 4 is a Raman spectrum of chitosan-based biochar (BC-800) having a porous structure and a high specific surface area according to example 1 of the present invention and chitosan-based biochar (BC-700) according to comparative example 1.
FIG. 5 is a graph showing the effect of chitosan-based biochar (BC-800) having a porous structure and a high specific surface area on the removal of 2, 4-dichlorophen when persulfate is activated in example 2 of the present invention.
FIG. 6 is a graph showing the effect of chitosan-based biochar (BC-700) on the removal of 2, 4-dichlorophen when persulfate is activated in example 2 of the present invention.
FIG. 7 is a graph showing the effect of chitosan-based biochar having a porous structure and a high specific surface area on the removal of 2, 4-dichlorophen when persulfate is activated under different pH conditions in example 3 of the present invention.
FIG. 8 is a graph showing the effect of chitosan-based biochar having a porous structure and a high specific surface area on the removal of 2, 4-dichlorophen when persulfate is activated under different ion conditions in example 4 of the present invention.
Fig. 9 is a graph showing the effect of chitosan-based biochar having a porous structure and a high specific surface area on removing methyl orange and oxytetracycline when persulfate is activated in examples 5 and 6 of the present invention.
Detailed Description
The invention is further described below with reference to the drawings and the specific preferred embodiments, without thereby limiting the scope of protection of the invention. The materials and equipment used in the following examples are commercially available. Unless otherwise stated, the initial pH of the organic contaminant water used in the present invention is 7.
Example 1:
the invention relates to a preparation method of chitosan-based biochar with a porous structure and a high specific surface area, which comprises the following steps:
(1) Dispersing chitosan in a mixed solvent of potassium hydroxide, urea and water, wherein the mass ratio of the chitosan to the potassium hydroxide to the urea to the water is 4: 11.04: 7.68: 77.28, fully stirring to dissolve the chitosan and the urea to obtain a chitosan solution, and then sequentially freezing and unfreezing the chitosan solution, specifically: freezing at-24 deg.C for 18h, thawing at 4 deg.C for 18h, performing circulation treatment for 4 times to obtain light yellow viscous solution, magnetically stirring at 0 deg.C in water bath for 2h to obtain chitosan gel solution, drying at 30 deg.C for 6h in vacuum drying oven, removing a few bubbles, and performing chemical crosslinking reaction to obtain chitosan hydrogel. In this step, if the chitosan solution is not subjected to freezing treatment and thawing treatment, it cannot be effectively dissolved.
(2) Freezing and drying the chitosan hydrogel, namely freezing the chitosan hydrogel in an ultra-low temperature refrigerator, transferring the chitosan hydrogel to a vacuum freeze dryer, and drying at the temperature of minus 30 ℃ to minus 45 ℃ to obtain loose chitosan aerogel.
(3) Putting the chitosan aerogel into a tubular calcining furnace for pyrolysis (calcining), specifically: at N 2 Heating to 600 ℃ from room temperature at the heating rate of 5 ℃/min under the atmosphere, preserving heat for 2h, taking out a product, washing the product to be neutral by using water, and drying at 80 ℃ for 6h to obtain the Biochar Biochar-600.
(4) Putting the Biochar Biochar-600 into a tubular calcining furnace for pyrolysis (calcining), which specifically comprises the following steps: in N 2 Heating to 800 ℃ from room temperature at the heating rate of 5 ℃/min under the atmosphere, preserving heat for 2h, taking out and grinding to obtain the chitosan-based biochar with a porous structure and a high specific surface area, and recording as BC-800.
The method adopts a two-step calcination method, forms the biochar with a porous structure after one-time calcination, and then washes away the K remained on the surface of the biochar 2 CO 3 、K 2 And substances such as O, KOH and the like are subjected to secondary calcination, and if the substances are directly subjected to secondary calcination without washing, the residual substances are attached to the vicinity of the pore structure, so that the porosity of the material is remarkably reduced, and finally, chitosan-based biochar with large specific surface area and rich pore structure cannot be obtained. In addition, if the chitosan aerogel is directly heated to 800 ℃ for calcination, the temperature of the chitosan aerogel is not increasedThe process yields a carbon product, but rather forms a white alkaline solid that is readily soluble in water due to: the residual potassium hydroxide in the chitosan aerogel is thermally decomposed and activated at high temperature, namely KOH + C → K is mainly generated 2 CO 3 +K 2 O+H 2 The reaction, that is, potassium hydroxide etches away part of the carbon to form a porous carbon material, and the reaction proceeds faster at higher temperatures. Therefore, the chitosan-based biochar with large specific surface area and rich pore structure can be obtained by adopting a two-step calcination method.
The chitosan-based biochar with the porous structure and the high specific surface area prepared in the embodiment 1 of the invention has rich pore structures including three structures of micropores, mesopores and macropores, wherein the mesopore proportion is the highest, the average pore diameter is 3.43nm, and the BET specific surface area is 1748m 2 Per g, wherein the specific surface area of the micropores was 73.24m 2 (ii) the specific surface area of the mesopores is 1674.9m 2 Per g, pore volume of 0.976cm 3 (ii)/g, wherein the pore volume of the micropores is 0.0059cm 3 (g) the pore volume of the mesopores is 0.97cm 3 The proportion of mesopores is the largest, as can be seen in the/g.
Fig. 1 is SEM and TEM images of chitosan-based biochar having a porous structure and a high specific surface area, which was prepared in example 1 of the present invention. As can be seen from FIG. 1, the material has a large number of macropores, and the pore diameter is concentrated between 1 and 3 μm. In addition, the formation of graphitized carbon can be observed in a TEM image at a high magnification.
Comparative example 1:
a method for preparing chitosan-based biochar, which is different from the preparation method in example 1 in that only one pyrolysis is performed, comprising the following steps:
the loose chitosan aerogel prepared in example 1 was put into a tubular calciner for pyrolysis (calcination), specifically: at N 2 Heating to 700 ℃ from room temperature at the heating rate of 5 ℃/min under the atmosphere, preserving heat for 2h, taking out a product, washing to be neutral by adopting water, and drying at 80 ℃ for 6h to obtain chitosan-based biochar, which is recorded as BC-700.
FIG. 2 is a graph showing adsorption and desorption curves of chitosan-based biochar (BC-800) having a porous structure and a high specific surface area, which is manufactured in example 1 of the present invention, and chitosan-based biochar (BC-700) manufactured in comparative example 1. FIG. 3 is a pore size distribution diagram of chitosan-based biochar (BC-800) having a porous structure and a high specific surface area obtained in example 1 of the present invention and chitosan-based biochar (BC-700) obtained in comparative example 1. As can be seen from fig. 2 and 3, the pores of the chitosan-based biochar (BC-800) having a porous structure and a high specific surface area according to the present invention are mainly distributed in the mesoporous range, and the pore structure mainly including mesopores is more advantageous for rapid transfer of a substance. As can be seen from fig. 1, 2 and 3, the chitosan-based biochar having a porous structure and a high specific surface area of the present invention has a three-level pore structure of micropore-mesopore-macropore, and is mainly based on mesopores of 2-50 nm.
FIG. 4 is a Raman spectrum of chitosan-based biochar (BC-800) having a porous structure and a high specific surface area obtained in example 1 of the present invention and chitosan-based biochar (BC-700) obtained in comparative example 1. From the raman analysis of fig. 4, it was found that the ID/IG =0.967 for BC-800 in example 1 and the ID/IG =0.982 for BC-700 in comparative example 1, it was seen that the degree of graphitization of the material was increased after two-step calcination compared to one-step calcination. The chitosan-based biochar with the porous structure and the high specific surface area is used for activating persulfate to degrade organic pollutants through a non-free radical path, namely the chitosan-based biochar serves as a transmission medium to transfer electrons from the pollutants to the persulfate, so that the high graphitization degree is favorable for the degradation reaction.
As can be seen from FIGS. 2, 3 and 4, the specific surface area of BC-800 in example 1 is 1748m 2 Per g, the specific surface area of BC-700 in comparative example 1 is only 275.23m 2 Per g, total pore volume of only 0.1802cm 3 (ii) in terms of/g. Therefore, the carbon material can be further pyrolyzed by the two-step calcining method, the graphitization degree of the material is improved, the number and the volume of pores of the material are increased, and the specific surface area and the volume of the pores are obviously increased, so that the chitosan-based biochar with better catalytic activity is obtained.
Example 2:
an application of chitosan-based biochar with a porous structure and a high specific surface area in treating organic pollutants, in particular to a method for degrading 2, 4-dichlorophen in a water body by activating persulfate through the chitosan-based biochar with the porous structure and the high specific surface area, which comprises the following steps:
0.003g and 0.005g of chitosan-based biochar with a porous structure and a high specific surface area prepared in example 1 are added into 40mL and 50mg/L of 2, 4-dichlorophenol solution respectively, 0.3mL and 0.1mol/L of sodium persulfate solution are added, and degradation reaction is carried out for 90min under the oscillating condition of 30 ℃ and 150r/min of rotation speed, so that the degradation of 2, 4-dichlorophenol in the water body is finished.
Control group one: only the chitosan-based biochar having a porous structure and a high specific surface area prepared in example 1 was added, and sodium persulfate was not added, and the other conditions were the same as in example 2.
Control group two: the chitosan-based biochar obtained in comparative example 1 was substituted for the chitosan-based biochar having a porous structure and a high specific surface area obtained in example 1, and the other conditions were the same as in example 2.
Control group three: the 2, 4-dichlorophen in the water body is degraded by adding only the chitosan-based biochar prepared in the comparative example 1, and sodium persulfate is not added, and other conditions are the same as those of the example 2.
In the oscillating treatment process, samples are taken at 5min, 15min, 30min, 45min, 60min and 90min to measure the concentration of the 2, 4-dichlorophen, and the removal rate of the 2, 4-dichlorophen is calculated.
FIG. 5 is a graph showing the effect of chitosan-based biochar (BC-800) having a porous structure and a high specific surface area on the removal of 2, 4-dichlorophen when persulfate is activated in example 2 of the present invention. FIG. 6 is a graph showing the effect of chitosan-based biochar (BC-700) on the removal of 2, 4-dichlorophen when persulfate is activated in example 2 of the present invention. As can be seen from fig. 5 and 6, the chitosan-based biochar prepared by the two-step calcination method is superior to biochar obtained by pyrolysis at 700 ℃ in both adsorption effect and catalytic effect because: the specific surface area and the pore volume of the chitosan-based biochar prepared by the two-step calcination method are obviously increased, and the graphitization degree of the biochar is improved through pyrolysis at a higher temperature, so that the transfer of electrons is facilitated.
Example 3:
the method is used for investigating the influence of chitosan-based biochar with a porous structure and a high specific surface area on the degradation effect of organic pollutants under different pH conditions, and specifically comprises the following steps of activating persulfate to degrade 2, 4-dichlorophen in water bodies with different pH values by using the chitosan-based biochar with the porous structure and the high specific surface area:
taking 5 parts of 40mL and 50 mg/L2, 4-dichlorophenol solution, adjusting the pH values of the solution to be 3, 5, 7, 9 and 11 respectively, adding 0.005g of chitosan-based biochar with a porous structure and a high specific surface area prepared in example 1, adding 0.3mL and 0.1mol/L sodium persulfate solution, and carrying out degradation reaction for 45min under the oscillation condition of 30 ℃ and 150r/min of rotation speed to finish the degradation of the 2, 4-dichlorophenol in the water body.
In the oscillating treatment process, samples are taken at 5min, 15min, 30min and 45min to measure the concentration of the 2, 4-dichlorophen, and the removal rate of the 2, 4-dichlorophen is calculated.
FIG. 7 is a graph showing the effect of chitosan-based biochar having a porous structure and a high specific surface area on the removal of 2, 4-dichlorophen when persulfate is activated under different pH conditions in example 3 of the present invention. As can be seen from FIG. 7, after 5min of treatment, the chitosan-based biochar with a porous structure and a high specific surface area has the removal efficiency of more than 80% for the 2, 4-dichlorophen when the persulfate is activated under the acidic, neutral and alkaline conditions, and after 45min of treatment, the chitosan-based biochar with a porous structure and a high specific surface area has the removal efficiency of more than 90% for the 2, 4-dichlorophen when the persulfate is activated under the acidic, neutral and alkaline conditions, which indicates that the chitosan-based biochar with a porous structure and a high specific surface area has an excellent pH adaptation range and has a good application prospect in the aspect of treating phenolic wastewater.
Example 4:
the method is used for investigating the influence of chitosan-based biochar with a porous structure and a high specific surface area on the degradation effect of organic pollutants under different ion conditions, and specifically comprises the following steps of activating persulfate to degrade 2, 4-dichlorophen in water containing different ions by using the chitosan-based biochar with the porous structure and the high specific surface area, wherein the method comprises the following steps:
4 parts of a 40mL 50 mg/L2, 4-dichlorophenol solution, 2 parts of which are addedAdding NaCl to make Cl in the solution - The concentrations were 10mM, 400mM, respectively, and 2 additional portions of NaHCO were added 3 To make HCO in solution 3 - The concentrations are respectively 10mM and 400mM, then 0.005g of chitosan-based biochar with a porous structure and high specific surface area prepared in the example 1 is respectively added, 0.3mL of 0.1mol/L sodium persulfate solution is added, the degradation reaction is carried out for 45min under the oscillating condition of 30 ℃ and the rotating speed of 150r/min, and the degradation of the 2, 4-dichlorophen in the water body is completed.
In the oscillating treatment process, samples are taken at 5min, 15min, 30min and 45min to measure the concentration of 2, 4-dichlorophenol, and the removal rate of the 2, 4-dichlorophenol is calculated.
FIG. 8 is a graph showing the effect of chitosan-based biochar having a porous structure and a high specific surface area on the removal of 2, 4-dichlorophen when persulfate is activated under different ion conditions in example 4 of the present invention. As can be seen from FIG. 8, when Cl is present - 、HCO 3 - Even if Cl is present - And HCO 3 - The concentration is as high as 400mM, and the removal efficiency of the chitosan-based biochar with the porous structure and the high specific surface area to 2, 4-dichlorophen is over 94 percent when the persulfate is activated by the chitosan-based biochar, which indicates that the chitosan-based biochar with the porous structure and the high specific surface area has good anti-interference capability and good practical application prospect while the high degradation efficiency is maintained.
Example 5:
an application of chitosan-based biochar with a porous structure and a high specific surface area in treating organic pollutants, in particular to a method for degrading methyl orange in a water body by activating persulfate through the chitosan-based biochar with the porous structure and the high specific surface area, which comprises the following steps:
taking 2 parts of 50mg/L methyl orange solution, wherein the volumes of the methyl orange solution are 60mL and 80mL respectively, adding 0.005g of chitosan-based biochar with a porous structure and a high specific surface area prepared in example 1, adding 0.3mL of 0.1mol/L sodium persulfate solution, and carrying out degradation reaction for 90min under the oscillation condition of 30 ℃ and the rotation speed of 150r/min to finish the degradation of the methyl orange in the water body.
In the oscillating treatment process, samples are taken at 15min, 30min, 45min, 60min and 90min to determine the concentration of methyl orange, and the removal rate of the methyl orange is calculated.
Example 6:
an application of chitosan-based biochar with a porous structure and a high specific surface area in treating organic pollutants, in particular to application of chitosan-based biochar with a porous structure and a high specific surface area in activating persulfate to degrade oxytetracycline in a water body, which comprises the following steps:
taking 2 parts of 50mg/L oxytetracycline solution, wherein the oxytetracycline solution has the volume of 40mL and 60mL respectively, adding 0.005g of chitosan-based biochar with a porous structure and a high specific surface area prepared in example 1, adding 0.3mL of sodium persulfate solution and 0.1mol/L of sodium persulfate solution, and performing degradation reaction for 150min under the oscillation condition of 30 ℃ and 150r/min of rotation speed to finish the degradation of oxytetracycline in a water body.
In the oscillation treatment process, samples are taken at 5min, 15min, 30min, 45min, 90min and 150min to determine the concentration of the oxytetracycline, and the removal rate of the oxytetracycline is calculated.
Fig. 9 is a graph showing the effect of chitosan-based biochar having a porous structure and a high specific surface area on removing methyl orange and oxytetracycline when persulfate is activated in examples 5 and 6 of the present invention. As can be seen from fig. 9, the method of the present invention can rapidly remove methyl orange, and the removal rate decreases with the increase of the content of the pollutant, because: the amount of the biochar serving as the activator is limited, so that the activation sites provided by the biochar are also limited, and as the degradation reaction progresses, part of degradation products are attached to the surface of the biochar, and the catalytic activity of the biochar is also reduced. When the chitosan-based biochar with a porous structure and a high specific surface area is used for removing 2, 4-dichlorophen, the removal efficiency is reduced as the concentration of pollutants is increased. In addition, the reaction system has a certain removal effect on oxytetracycline, which shows that the chitosan-based biochar with the porous structure and the high specific surface area has a wide application range. However, under the same conditions, the chitosan-based biochar with a porous structure and a high specific surface area of the invention has lower removal efficiency on oxytetracycline than 2, 4-dichlorophen and methyl orange, and has a degradation time significantly longer than that of the two, which may be caused by: the electron donating ability of terramycin is lower than that of 2, 4-dichlorophen and methyl orange, so that electrons are difficult to be transferred to persulfate through biochar.
From the above results, compared with the chitosan-based biochar prepared by the conventional method, the chitosan-based biochar prepared by the preparation method disclosed by the invention comprises a large number of micropores, mesopores and macropores, wherein the proportion of the mesopores (2-50 nm) is the largest, the pore structure is rich, the specific surface area and the number of active sites of the chitosan-based biochar can be obviously improved, the transfer of substances in a catalytic degradation system can be accelerated, and meanwhile, the graphitization degree of the chitosan-based biochar is higher, so that the rapid degradation of organic pollutants can be realized, the high-efficiency activation of persulfate can also be realized, and the chitosan-based biochar has the advantages of high specific surface area, rich pore structure, good catalytic performance, strong anti-interference performance, environmental friendliness and the like, can be used for activating persulfate to degrade the organic pollutants in a water body, and shows excellent removal effect and high-efficiency removal efficiency, and has a good application prospect. In addition, the preparation method has the advantages of simple process, low cost, no secondary pollution and the like, is suitable for large-scale preparation, and is beneficial to industrial application.
The foregoing is illustrative of the preferred embodiments of the present invention and is not to be construed as limiting the invention in any way. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make many possible variations and modifications to the disclosed embodiments, or equivalent modifications, without departing from the spirit and scope of the invention, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention.
Claims (10)
1. A preparation method of chitosan-based biochar with a porous structure and a high specific surface area is characterized by comprising the following steps:
s1, dissolving chitosan in an alkaline solution to obtain a chitosan solution, performing freezing-unfreezing circulation treatment on the chitosan solution, stirring, and drying to obtain chitosan hydrogel; the alkaline solution is a mixed solution containing potassium hydroxide and a nitrogen source;
s2, carrying out freeze drying treatment on the chitosan hydrogel obtained in the S1 to obtain chitosan aerogel;
s3, heating the chitosan aerogel obtained in the S2 to 600-650 ℃, calcining, washing and drying;
and S4, heating the product obtained after drying in the S3 to 800-850 ℃ for calcining to obtain the chitosan-based biochar with a porous structure and a high specific surface area.
2. A method for preparing a chitosan-based biochar having a porous structure and a high specific surface area as claimed in claim 1, wherein in S1, the alkaline solution is prepared by dissolving potassium hydroxide and a nitrogen source into a solvent, the mass ratio of the chitosan, the potassium hydroxide, the nitrogen source and the solvent is 4-5: 11-12: 7-8: 77-80, and the nitrogen source is at least one of urea, cyanamide and melamine; the solvent is water.
3. A method for preparing a chitosan-based biochar having a porous structure and a high specific surface area as claimed in claim 2, wherein in S1, the freezing-thawing cycle treatment is to sequentially perform freezing treatment and thawing treatment on a chitosan solution, and the freezing treatment and the thawing treatment are repeated for not less than 3 times; the freezing treatment is carried out at the temperature of-20 ℃ to-40 ℃; the time of single freezing treatment is 12-24 h; the unfreezing treatment is carried out at the temperature of 4-6 ℃; the time of single unfreezing treatment is 12-24 h.
4. A preparation method of a chitosan-based biochar having a porous structure and a high specific surface area as claimed in any one of claims 1 to 3, wherein in S3, the calcination is performed under an inert atmosphere, the inert atmosphere is nitrogen, the temperature rise rate during the calcination is 5-10 ℃/min, and the calcination time is 2-2.5 h;
and/or in S4, the calcination is carried out in an inert atmosphere, the inert atmosphere is nitrogen, the heating rate in the calcination process is 5-10 ℃/min, and the calcination time is 2-2.5 h.
5. A method for preparing a chitosan-based biochar having a porous structure and a high specific surface area according to any one of claims 1-3, wherein in the S1, the stirring is performed at 0 ℃, the stirring time is 2-3 h, the drying is performed under vacuum condition, the drying temperature is 15-35 ℃, and the drying time is 4-6 h;
and/or, in the S2, the freeze-drying is performed under vacuum conditions;
and/or in the S3, the drying temperature is 80-120 ℃, and the drying time is 6-10 h.
6. A chitosan-based biochar having a porous structure and a high specific surface area, characterized in that it is produced by the production method according to any one of claims 1 to 5.
7. The chitosan-based biochar having a porous structure and a high specific surface area according to claim 6, wherein the chitosan-based biochar comprises three pore structures of micro-pores, meso-pores and macro-pores, and the BET specific surface area of the chitosan-based biochar is 1600m 2 /g～2400m 2 Per g, the pore volume of the chitosan-based biochar is 0.8cm 3 /g～1.2cm 3 /g。
8. Use of the chitosan-based biochar having a porous structure and a high specific surface area as set forth in claim 6 or 7 for treating organic pollutant wastewater.
9. Use according to claim 8, characterized in that it comprises the following steps: mixing chitosan-based biochar with a porous structure and a high specific surface area, persulfate and the water containing organic pollutants, and carrying out degradation reaction to finish the degradation of the organic pollutants in the water.
10. The use according to claim 9, wherein the chitosan-based biochar is added in an amount of 0.05 to 0.125g per liter of water containing organic pollutants, the persulfate is added in an amount of 0.15 to 0.75mmol per liter of water containing organic pollutants, the persulfate is sodium persulfate, the initial concentration of the organic pollutants in the water containing organic pollutants is 50 to 100mg/L, the initial pH value of the water containing organic pollutants is 3 to 11, the organic pollutants in the water containing organic pollutants comprise at least one of a phenolic compound, a dye and an antibiotic, the phenolic compound is at least one of 2, 4-dichlorophenol and phenol, the dye is at least one of methyl orange and methylene blue, the antibiotic is at least one of oxytetracycline and tetracycline hydrochloride, the degradation reaction is carried out under oscillation conditions, the rotation speed of the oscillation is 120 to 200r/min, the degradation reaction temperature is 15 ℃ to 200 ℃, and the degradation reaction time is 5 to 60min.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116272926A (en) * | 2023-05-15 | 2023-06-23 | 成都达奇科技股份有限公司 | Preparation method of dye wastewater decolorizing active carbon, product and dye wastewater decolorizing method |
| CN116371419A (en) * | 2023-04-21 | 2023-07-04 | 中南大学 | Microbial carbon-supported manganese-cobalt catalyst and preparation method and application thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103922328A (en) * | 2014-04-18 | 2014-07-16 | 山东大学 | Method for preparing nitrogenous hierarchical pore three-dimensional graphene by using chitosan |
| CN109292883A (en) * | 2018-10-23 | 2019-02-01 | 湖南大学 | A method of graphitization charcoal and its degradation Organic Pollutants In Water |
| US20190077664A1 (en) * | 2016-03-16 | 2019-03-14 | The Regents Of The University Of California | Three-dimensional hierarchical porous carbon foams for supercapacitors |
| CN111282549A (en) * | 2020-02-28 | 2020-06-16 | 上海电力大学 | Preparation method and application of adsorption degradation material |
| CN111389358A (en) * | 2020-03-25 | 2020-07-10 | 武汉科技大学 | Preparation method of modified nitrogen-doped carbon aerogel |
| CN114272895A (en) * | 2021-12-09 | 2022-04-05 | 湖南大学 | Nitrogen-sulfur-phosphorus co-doped ordered porous biochar and preparation method and application thereof |
| CN115043479A (en) * | 2022-05-17 | 2022-09-13 | 山西财经大学 | Nitrogen-doped biochar as well as preparation method and application thereof |
-
2022
- 2022-09-23 CN CN202211167489.2A patent/CN115634679B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103922328A (en) * | 2014-04-18 | 2014-07-16 | 山东大学 | Method for preparing nitrogenous hierarchical pore three-dimensional graphene by using chitosan |
| US20190077664A1 (en) * | 2016-03-16 | 2019-03-14 | The Regents Of The University Of California | Three-dimensional hierarchical porous carbon foams for supercapacitors |
| CN109292883A (en) * | 2018-10-23 | 2019-02-01 | 湖南大学 | A method of graphitization charcoal and its degradation Organic Pollutants In Water |
| CN111282549A (en) * | 2020-02-28 | 2020-06-16 | 上海电力大学 | Preparation method and application of adsorption degradation material |
| CN111389358A (en) * | 2020-03-25 | 2020-07-10 | 武汉科技大学 | Preparation method of modified nitrogen-doped carbon aerogel |
| CN114272895A (en) * | 2021-12-09 | 2022-04-05 | 湖南大学 | Nitrogen-sulfur-phosphorus co-doped ordered porous biochar and preparation method and application thereof |
| CN115043479A (en) * | 2022-05-17 | 2022-09-13 | 山西财经大学 | Nitrogen-doped biochar as well as preparation method and application thereof |
Non-Patent Citations (1)
| Title |
|---|
| KEREN LU等: "Preparation of nitrogen self-doped hierarchical porous carbon with rapid-freezing support for cooperative pollutant adsorption and catalytic oxidation of persulfate", 《SCIENCE OF THE TOTAL ENVIRONMENT》, vol. 752, pages 142282 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116371419A (en) * | 2023-04-21 | 2023-07-04 | 中南大学 | Microbial carbon-supported manganese-cobalt catalyst and preparation method and application thereof |
| CN116272926A (en) * | 2023-05-15 | 2023-06-23 | 成都达奇科技股份有限公司 | Preparation method of dye wastewater decolorizing active carbon, product and dye wastewater decolorizing method |
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