A porous biochar adsorption material for water purification, a preparation method, and a method for treating pharmaceutical wastewater using the same

Abstract

A porous biochar adsorption material for water purification, a preparation method and a method for using the same to treat pharmaceutical wastewater. A porous biochar adsorption material for water purification, comprising porous biochar particles with a porosity of 70-85%, wherein the porous biochar particles comprise porous biochar particles doped with Zn ions and Mn ions. The present application clarifies the porosity of the porous biochar adsorption material for water purification and the doping of Zn ions and Mn ions. The high porosity gives the biochar material a huge specific surface area, providing ample space for the adsorption and reaction of substances. This means that when treating pharmaceutical wastewater, more drug molecules can contact the biochar surface, thereby improving the adsorption efficiency. Zn ion and Mn ion doping form special active sites inside the biochar, which can activate persulfate and generate free radicals with strong oxidizing properties, thereby efficiently degrading pollutants in the pharmaceutical wastewater.

Description

Technical Field

[0001] The present application relates to the field of porous biochar materials, and in particular to a porous biochar adsorption material for water purification, a preparation method, and a method for treating pharmaceutical wastewater using the same. Background Art

[0002] With the acceleration of industrialization and the improvement of people's living standards, various pollutants pose an increasingly severe threat to the environment. Among them, the residual problem of antibiotic pollutants in water bodies has attracted much attention. Levofloxacin (LEVO), a widely used antibiotic, is difficult to degrade naturally when it enters the aquatic environment in large quantities. This not only damages aquatic ecosystems but can also be transmitted through the food chain, threatening human health. Traditional wastewater treatment methods, such as physical filtration and chemical precipitation, have limited effectiveness in removing low-concentration, highly stable antibiotic pollutants. Therefore, the development of efficient antibiotic wastewater treatment technologies is urgent.

[0003] Biochar, a carbon-based material with a rich pore structure and large specific surface area, has shown great potential in wastewater treatment. It can effectively remove a variety of pollutants through physical adsorption and chemical reactions of surface functional groups.

[0004] In response to the above-mentioned prior art, the inventors discovered that the pore structure of biochar prepared using a single-material pore-forming agent is relatively simple, and the mass transfer efficiency and active site utilization efficiency during interaction with pollutants need to be improved. Furthermore, for some pollutant degradation processes requiring specific catalytic activity, the catalytic performance of single-template biochar is insufficient, making it unable to efficiently activate oxidants and achieve deep degradation of pollutants. Summary of the Invention

[0005] In order to improve the above technical problems, the present application provides a water purification porous biochar adsorption material, a preparation method and a method for using the same to treat pharmaceutical wastewater.

[0006] In a first aspect, the present application provides a porous biochar adsorption material for water purification, which adopts the following technical solution:

[0007] A porous biochar adsorption material for water purification includes porous biochar particles with a porosity of 70-85%, wherein the porous biochar particles include porous biochar particles doped with Zn ions and Mn ions.

[0008] Through the above technical solution, this application clarifies the porosity of the porous biochar adsorption material for water purification and the embedded Zn ions and Mn ions. The high porosity gives the biochar material a huge specific surface area, providing ample space for the adsorption and reaction of substances. This means that when treating pharmaceutical wastewater, more drug molecules can contact the biochar surface, thereby improving the adsorption efficiency. The embedded Zn ions and Mn ions form special active sites inside the biochar, which can activate persulfate and produce free radicals with strong oxidizing properties, thereby efficiently degrading pollutants in pharmaceutical wastewater.

[0009] Compared with the pore-forming agent materials in traditional technical solutions, a single template reagent can only simply serve as a pore-forming agent to perform a single pore-forming treatment on the carbon material, and cannot form a good pore-through structure. The present application further improves the pore structure of the porous biochar adsorption material for water purification prepared in the present application by embedding Zn ions and Mn ions inside the biochar material and etching pores through Zn ions. At the same time, the porous biochar adsorption material for water purification prepared in the present application contains Zn and Mn elements. When it subsequently comes into contact with persulfate, it can quickly attack the drug molecules in the pharmaceutical wastewater through electron transfer and other means, and oxidize and decompose them into small molecular substances, thereby achieving efficient treatment of pharmaceutical wastewater.

[0010] Furthermore, the relative proportion of the C element in the porous biochar adsorption material for water purification is ≤93.15%, and the relative proportion of the O element is ≥5.46%.

[0011] Through the above technical solution, this application defines the relative ratios of carbon and oxygen in porous biochar adsorption materials for water purification. This defined ratio allows the presence of a certain number of oxygen-containing functional groups in the material. These oxygen-containing functional groups can form hydrogen bonds, electrostatic interactions, and other interactions with drug molecules, promoting their adsorption.

[0012] In a second aspect, the present application provides a method for preparing a porous biochar adsorption material for water purification, comprising the following preparation steps:

[0013] Primary heat treatment: washing and drying the biochar raw material, mixing it with the template reagent A and placing it in a pyrolysis device, and collecting the primary pyrolysis biochar after the primary pyrolysis treatment;

[0014] Secondary heat treatment: take the primary pyrolysis biochar, mix it with the template reagent B, and place it in a pyrolysis device. The secondary pyrolysis biochar is collected for secondary pyrolysis treatment;

[0015] Washing and drying: The secondary pyrolysis biochar material is washed to remove soluble metal elements and then dried to prepare a porous biochar adsorption material for water purification.

[0016] Through the above technical solution, the present application uses a dual template reagent to prepare biochar material. Compared with the biochar particles prepared from a single template reagent material, the present application uses a pyrolysis reaction in the biomass raw material under the action of template reagent A during the preparation process. Template reagent A will react chemically with the organic matter in the biomass, or volatilize and decompose during the pyrolysis process, thereby forming an initial pore structure in the biochar. During the secondary heat treatment, template reagent B further modifies the primary pyrolysis biochar, fills it into the existing pores, and forms new active sites on the surface of the biochar. At the same time, the high temperature conditions of the secondary heat treatment also contribute to the further carbonization and structural optimization of the biochar. The washing and drying steps are to remove impurities such as soluble metal salts remaining in the biochar, to avoid these impurities from having an adverse effect on the subsequent wastewater treatment process, and to prevent excess soluble metal salts from reacting with persulfates.

[0017] Furthermore, the template reagent A includes MnCl2 powder, and the C in the primary pyrolysis biochar is MnCl2·4H2O=(1:0-1.0).

[0018] Furthermore, the template reagent B includes ZnCl2 powder, and the secondary pyrolysis biochar contains C:ZnCl2·4H2O=(1:0-2).

[0019] Through the above technical solution, the application optimizes the addition ratio of zinc and manganese elements in template reagent A and template reagent B, thereby greatly improving the activation efficiency of persulfate through the synergistic work of the active sites formed by the two. Compared with a single template reagent, the biochar modified with a dual template reagent can produce more strong oxidizing free radicals. The biochar under the synergistic effect has been improved in both adsorption and catalytic performance, achieving a synergistic effect of physical adsorption and chemical catalysis. When treating pharmaceutical wastewater, it can not only quickly adsorb drug molecules, but also efficiently degrade them, improving the treatment effect and processing speed.

[0020] On this basis, the present application further adjusted the order of adding ZnCl2 and MnCl2. Through the addition order of "manganese first and zinc later", MnCl2 was introduced at the low temperature stage. Although no pores were directly formed, the carbon skeleton was pre-softened through the coordination effect of Mn with the hydroxyl (-OH) in the biomass. At the same time, part of the MnCl2 was converted into MnO crystal phase and embedded in the carbon layer, laying the structural foundation for subsequent pore formation. Subsequently, ZnCl2 was introduced at a high temperature stage to deeply etch the pre-softened carbon skeleton to form a multi-level pore structure, while the high temperature simultaneously promoted the further removal of Mn species. The step-by-step strategy enables the synergistic realization of MnCl2 pre-regulation of the skeleton, ZnCl2 directional pore expansion and demetallization: the carbon layer pretreated with Mn is more easily etched by Zn to produce rich defects, and the defect density is strongly correlated with the catalytic activity, ultimately further improving the activation efficiency of the dual-template biochar compared to the single template.

[0021] Furthermore, the template reagent A and the template reagent B are both provided with a dispersion coating carrier, and the dispersion coating carrier includes three-dimensional porous graphene foam particles.

[0022] Furthermore, the template reagent A is prepared using the following scheme:

[0023] After surface activation treatment of three-dimensional porous graphene foam particles, they are washed, dried, and immersed in a MnCl2-N,N-dimethylformamide solution. After magnetic stirring, they are vacuum-dried and placed in a reaction furnace. Under the protection of inert gas, the temperature is increased and kept warm, and the particles are ground and sieved to prepare a template reagent A.

[0024] Furthermore, the template reagent B is prepared using the following scheme:

[0025] After surface activation treatment of three-dimensional porous graphene foam particles, they are washed, dried, and immersed in a ZnCl2-N,N-dimethylformamide solution. After magnetic stirring, they are vacuum-dried and placed in a reaction furnace. Under the protection of inert gas, the temperature is increased and kept warm, and the particles are ground and sieved to prepare template reagent B.

[0026] Furthermore, the three-dimensional porous graphene foam particles are made using the following technical solutions:

[0027] A graphene oxide dispersion and polystyrene microspheres are stirred and mixed, hydrazine hydrate is added dropwise and stirred, the temperature is increased and pressure is applied, the filter cake is filtered and collected, the filter cake is placed in a toluene solution, stirred and mixed, and rinsed with deionized water, vacuum dried, ground and dispersed to prepare three-dimensional porous graphene foam particles.

[0028] Through the above technical solution, the present application optimizes the structure of template reagent A and template reagent B, and selects three-dimensional porous graphene foam particles as dispersed coating carriers to provide a stable and high specific surface area support carrier for the load of zinc chloride and manganese chloride in biochar materials. In the primary heat treatment stage of biochar preparation, when the three-dimensional graphene foam is mixed with the biomass carbon raw material and manganese chloride, its three-dimensional network can disperse the biomass carbon raw material and manganese chloride to avoid local agglomeration. This allows biomass carbon to grow around the three-dimensional graphene foam during pyrolysis to form a more uniform pore structure. At the same time, manganese chloride is more evenly distributed in the biochar matrix under the support of the three-dimensional graphene foam, which helps to form a more stable interaction with biochar in the future.

[0029] Before the secondary pyrolysis, the primary pyrolysis products already contain MnCl2 pyrolysis derivatives. When biochar is directly mixed with zinc chloride powder, the Mn-containing carbon skeleton formed by the previous pyrolysis serves as a structural support. The residual Mn-O active sites on its surface physically adsorb and fix the ZnCl2 particles, forming a spatially dispersed Zn-Mn system. During the secondary pyrolysis process, the ZnCl2 first melts and penetrates the interstices of the carbon layer, then volatilizes at high temperature to produce a gaseous etchant. At this point, the residual Mn species from the primary pyrolysis play a dual role: first, they act as anchors to inhibit localized ZnCl2 aggregation and promote uniform etchant release; second, they form transient Zn-Mn-O intermediates with the volatilized Zn species. These intermediates then simultaneously detach from the carbon matrix during subsequent pyrolysis, maintaining the structural stability of the carbon skeleton while avoiding metal residues. This step-by-step loading strategy, through the spatiotemporal synergy of "Mn pre-dispersion-Zn dynamic etching," achieves a gradient release of the bimetallic reagent and the targeted construction of carbon defects, significantly improving the uniformity of active sites compared to traditional blending methods.

[0030] In a third aspect, the present application provides a method for treating pharmaceutical wastewater using a water purification porous biochar adsorption material, using the following technical solutions:

[0031] A method for treating pharmaceutical wastewater using a water purification porous biochar adsorption material comprises the following steps:

[0032] After adding persulfate to the wastewater to be treated, add the water purification porous biochar adsorption material and stir at room temperature;

[0033] After adding a quenching agent for quenching treatment, the wastewater degradation treatment can be completed.

[0034] Through the above technical solution, the porous biochar adsorption material for water purification has a rich pore structure and active sites, which can adsorb drug molecules to the surface of the biochar through physical adsorption and chemical adsorption. The added persulfate undergoes a decomposition reaction under the action of the active sites on the biochar surface, producing strong oxidizing substances such as sulfate radicals and hydroxyl radicals. These free radicals are extremely reactive and can quickly attack the chemical bonds in the drug molecules, oxidizing them and decomposing them into small molecules. Stirring at room temperature can evenly disperse the biochar material in the wastewater, increase the contact opportunities between the biochar and the drug molecules and persulfate, and improve the reaction efficiency. The addition of a quencher can react with the free radicals, terminate the chain reaction of the free radicals, and prevent the continued oxidation of other substances, thereby accurately measuring the residual amount of drugs in the treated wastewater and evaluating the treatment effect.

[0035] In summary, this application has the following beneficial effects:

[0036] First, this application clarifies the porosity of porous biochar adsorption materials for water purification and the embedded Zn ions and Mn ions. The high porosity gives the biochar material a huge specific surface area, providing ample space for the adsorption and reaction of substances. This means that when treating pharmaceutical wastewater, more drug molecules can contact the biochar surface, thereby improving the adsorption efficiency. The embedded Zn ions and Mn ions form special active sites inside the biochar, which can activate persulfate and produce free radicals with strong oxidizing properties, thereby efficiently degrading pollutants in pharmaceutical wastewater.

[0037] Compared to conventional pore-forming materials, a single template agent can only serve as a simple pore-forming agent for the carbon material, failing to form a well-defined, interconnected pore structure. This application further adjusts the order of ZnCl2 and MnCl2 addition, introducing MnCl2 at a low temperature. While this does not directly form pores, it pre-softens the carbon skeleton through the coordination of Mn with hydroxyl (-OH) groups in the biomass. Simultaneously, some MnCl2 is converted into MnO crystals and embedded in the carbon layer, laying the structural foundation for subsequent pore formation. Subsequently, ZnCl2 is introduced at a high temperature to deeply etch the pre-softened carbon skeleton, forming a multi-level pore structure. The high temperature also promotes the further removal of Mn species. This step-by-step strategy enables the synergistic effects of MnCl2 pre-modulation of the skeleton, ZnCl2-directed pore expansion, and demetallization. The Mn-pretreated carbon layer is more susceptible to Zn etching, generating a rich defect population. The defect density is strongly correlated with catalytic activity, ultimately improving the activation efficiency of the dual-template biochar compared to a single template.

[0038] Second, by optimizing the structure of template reagent A and template reagent B, and selecting three-dimensional porous graphene foam particles as a dispersion coating carrier, a stable and high specific surface area support carrier is provided for the loading of zinc chloride and manganese chloride in biochar materials. During the primary heat treatment stage of biochar preparation, when the three-dimensional graphene foam is mixed with the biomass carbon raw material and manganese chloride, its three-dimensional network can disperse the biomass carbon raw material and manganese chloride to avoid local agglomeration. This allows the biomass carbon to grow around the three-dimensional graphene foam during the pyrolysis process, forming a more uniform pore structure. At the same time, manganese chloride, supported by the three-dimensional graphene foam, is more evenly distributed in the biochar matrix, which helps to form a more stable interaction with the biochar later.

[0039] Before the secondary heat treatment, when the three-dimensional graphene foam loaded with zinc chloride and manganese chloride is mixed with the secondary pyrolysis biochar, the network structure of the three-dimensional graphene foam acts as a skeleton, evenly dispersing the zinc chloride and manganese chloride within the biochar system. During the secondary pyrolysis process, even though the three-dimensional graphene foam may undergo some structural changes at high temperatures, it still maintains the structural stability of the system to a certain extent, allowing the zinc chloride and manganese chloride to interact more fully with the biochar during pyrolysis, promoting the formation of stable chemical bonding or physical adsorption between the three, and improving the overall structural stability and loading uniformity of the biochar material.

[0040] Third, the present application purifies porous biochar adsorption materials through water bodies with rich pore structures and active sites, which can adsorb drug molecules to the biochar surface through physical adsorption and chemical adsorption. At the same time, the large specific surface area and rich pore structure of the three-dimensional graphene foam give it certain adsorption properties. When loaded with zinc ions and manganese ions in the biochar material, the three produce a synergistic effect in adsorbing pollutants in pharmaceutical wastewater. The pore structure of the three-dimensional graphene foam can serve as a preliminary adsorption site to physically adsorb large molecular pollutants in the wastewater. At the same time, the loaded zinc ions and manganese ions can undergo chemical adsorption or complex reaction with the pollutants. The synergistic effect of this physical adsorption and chemical adsorption greatly improves the adsorption capacity of biochar materials for pollutants in pharmaceutical wastewater. Moreover, the presence of three-dimensional graphene foam can also promote the rapid achievement of adsorption equilibrium, shorten the adsorption time, and improve treatment efficiency, further reflecting its synergistic effect with zinc ions and manganese ions in adsorption properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a SEM image of the porous biochar adsorption material for water purification prepared in Example 1 of the present application;

[0042] Figure 2 This is a SEM image of the porous biochar adsorption material for water purification prepared in Example 2 of the present application;

[0043] Figure 3 This is a TEM image of the porous biochar adsorption material for water purification prepared in Example 1 of the present application;

[0044] Figure 4 This is a SEM image of the porous biochar material prepared in Comparative Example 1 of this application;

[0045] Figure 5 This is the SEM image of the porous biochar material prepared in Comparative Example 2 of this application.

[0046] Figure 6 This is an EDS mapping diagram of the porous biochar adsorption material for water purification prepared in Example 1 of the present application;

[0047] Figure 7 LEVO curves of the degradation of the biochar materials prepared in Examples 1-3 and Comparative Examples 1-2 of the present application. DETAILED DESCRIPTION

[0048] The present application is further described in detail below with reference to the embodiments.

[0049] Preparation Example 1

[0050] Preparation of three-dimensional porous graphene foam particles:

[0051] 5 g / L of graphene oxide dispersion was ultrasonically treated in a 200 W ultrasonic cleaner for 45 min. 10 g of polystyrene microspheres with a diameter of 5 μm were added to 10 L of the ultrasonically treated graphene oxide dispersion, stirred for 30 min, and the mixture was collected.

[0052] To 5L of the mixed solution, 5g of hydrazine hydrate was added dropwise with continuous stirring. Upon completion, the mixture was transferred to a reactor, sealed, and reacted in an oven at 180°C for 12 hours. After the reaction, the product was repeatedly washed with anhydrous ethanol and deionized water to remove surface impurities and unreacted reagents. The product was then immersed in a toluene solution and stirred at 80°C for 12 hours to dissolve the polystyrene microsphere template. The product was then washed several times with anhydrous ethanol and deionized water, frozen at -80°C for 12 hours, and dried under a vacuum of 10-3 Pa for 24 hours to obtain a dry three-dimensional graphene foam.

[0053] Preparation Example 2

[0054] Template Reagent A

[0055] 20 g of the three-dimensional porous graphene foam particles prepared in Preparation Example 1 were surface activated in 5% hydrochloric acid for 30 min, rinsed with deionized water until the washing liquid was neutral, and then dried in an oven for 3 h. 10 g of the surface-activated three-dimensional porous graphene foam particles were collected and immersed in 2 L of 10% MnCl2-N,-dimethylformamide solution. After magnetic stirring at room temperature for 12 h, the mixture was filtered, vacuum dried, and placed in a reactor. Under nitrogen protection, the mixture was heated to 500°C at a rate of 3°C / min and kept warm for 1.5 h. The mixture was then ground and sieved to prepare template reagent A.

[0056] Preparation Example 3

[0057] Template Reagent B

[0058] 20 g of the three-dimensional porous graphene foam particles prepared in Preparation Example 1 were surface activated in 5% hydrochloric acid for 30 min, rinsed with deionized water until the washing liquid was neutral, and then dried in an oven for 3 h. 10 g of the surface-activated three-dimensional porous graphene foam particles were collected and immersed in 2 L of 10% ZnCl2-N,-dimethylformamide solution. After magnetic stirring at room temperature for 12 h, the mixture was filtered, vacuum dried, and placed in a reactor. Under nitrogen protection, the mixture was heated to 500°C at a rate of 3°C / min and kept warm for 1.5 h. The mixture was then ground and sieved to prepare template reagent B.

[0059] Example 1

[0060] A method for preparing a porous biochar adsorption material for water purification comprises the following steps:

[0061] Primary heat treatment: Wash wolfberries three times with deionized water and dry them in a vacuum drying oven at 60°C overnight. Mix wolfberries and MnCl2·4H2O powder evenly and place them in a crucible. Transfer the mixture to a tube furnace and heat the mixture to 680°C at a rate of 5°C / min under a nitrogen atmosphere. Pyrolysis is then carried out for 45 minutes. It should be noted that during the primary heat treatment, the amount of MnCl2 powder added must be controlled to ensure that the ratio of C to MnCl2·4H2O in the primary pyrolysis biochar is 1:1.

[0062] Secondary heat treatment: The primary pyrolysis biochar obtained in the first step was allowed to cool to room temperature, then mixed evenly with ZnCl2·4H2O and placed in a crucible. The mixture was then transferred to a tube furnace and heated to 880°C at a rate of 5°C / min under a nitrogen atmosphere. The mixture was then pyrolyzed for 100 min. It should be noted that during the secondary heat treatment, the amount of ZnCl2 powder added needed to be controlled so that the C:ZnCl2·4H2O ratio in the secondary pyrolysis biochar was (1:0.2).

[0063] Washing and drying: The material after secondary heat treatment and calcination was washed with deionized water and 1 mol / L hydrochloric acid respectively to remove residual Zn and Mn until the pH of the supernatant was neutral, and then dried in a vacuum oven at 60°C overnight to prepare a porous biochar adsorption material for water purification with a porosity of 74.7%.

[0064] A method for treating pharmaceutical wastewater using a water purification porous biochar adsorption material comprises the following steps:

[0065] 150 mg of potassium persulfate was added to 1000 mL of 20 mg / L levofloxacin solution, and the mixture was stirred to obtain a mixed solution. Then, the water purification porous biochar adsorption material was added to the mixed solution at an addition amount of 45 mg / L, and the mixture was stirred and quenched with 2 mL of methanol to complete the treatment steps of the pharmaceutical wastewater.

[0066] Example 2

[0067] A method for preparing a porous biochar adsorption material for water purification comprises the following steps:

[0068] Primary heat treatment: Wash wolfberries three times with deionized water and dry them in a vacuum drying oven at 60°C overnight. Mix wolfberries and MnCl2·4H2O powder evenly and place them in a crucible. Then transfer them to a tube furnace and heat them to 700°C at a rate of 5°C / min under a nitrogen atmosphere. Pyrolysis is then carried out for 60 minutes. It should be noted that during the primary heat treatment, the amount of MnCl2 powder added must be controlled to ensure that the ratio of C:MnCl2·4H2O in the primary pyrolysis biochar is (1:0.4).

[0069] Secondary heat treatment: The primary pyrolysis biochar obtained in the first step was allowed to cool to room temperature, then mixed evenly with ZnCl2·4H2O and placed in a crucible. The mixture was then transferred to a tube furnace and heated to 900°C at a rate of 5°C / min under a nitrogen atmosphere. The mixture was then pyrolyzed for 100 min. It should be noted that during the secondary heat treatment, the amount of ZnCl2 powder added needed to be controlled so that the ratio of C to ZnCl2·4H2O in the secondary pyrolysis biochar was (1:1.5).

[0070] Washing and drying: The material after secondary heat treatment and calcination was washed with deionized water and 1 mol / L hydrochloric acid respectively to remove residual Zn and Mn until the pH of the supernatant was neutral, and then dried in a vacuum oven at 60°C overnight to prepare a porous biochar adsorption material for water purification with a porosity of 73.6%.

[0071] A method for treating pharmaceutical wastewater using a water purification porous biochar adsorption material comprises the following steps:

[0072] Take 1000mL of 20mg / L levofloxacin solution, add 200mg of potassium persulfate, stir and mix to obtain a mixed solution, then add 50mg / L of water purification porous biochar adsorption material to the mixed solution, stir and mix, and quench with 2mL of methanol to complete the treatment steps of pharmaceutical wastewater.

[0073] Example 3

[0074] A method for preparing a porous biochar adsorption material for water purification comprises the following steps:

[0075] Primary heat treatment: Wash wolfberries three times with deionized water and dry them in a vacuum drying oven at 60°C overnight. Mix wolfberries and MnCl2·4H2O powder evenly and place them in a crucible. Transfer the mixture to a tube furnace and heat at 5°C / min to 720°C under a nitrogen atmosphere. Pyrolysis is then carried out for 45 minutes. It should be noted that during the primary heat treatment, the amount of MnCl2 powder added must be controlled to achieve a C:MnCl2·4H2O ratio of 1:0.6 in the primary pyrolysis biochar.

[0076] Secondary heat treatment: The primary pyrolysis biochar obtained in the first step was allowed to cool to room temperature, then mixed evenly with ZnCl2·4H2O and placed in a crucible. The mixture was then transferred to a tube furnace and heated to 920°C at a rate of 5°C / min under a nitrogen atmosphere. The mixture was then pyrolyzed for 100 min. It should be noted that during the secondary heat treatment, the amount of ZnCl2 powder added needed to be controlled so that the ratio of C to ZnCl2·4H2O in the secondary pyrolysis biochar was (1:2).

[0077] Washing and drying: The material after secondary heat treatment and calcination was washed with deionized water and 1 mol / L hydrochloric acid respectively to remove residual Zn and Mn until the pH of the supernatant was neutral, and then dried in a vacuum oven at 60°C overnight to prepare a porous biochar adsorption material for water purification with a porosity of 75.3%.

[0078] A method for treating pharmaceutical wastewater using a water purification porous biochar adsorption material comprises the following steps:

[0079] Take 1000mL of 20mg / L levofloxacin solution, add 250mg of potassium persulfate, stir and mix to obtain a mixed solution, then add the water purification porous biochar adsorption material to the mixed solution at an addition amount of 55mg / L, stir and mix, and quench with 2mL of methanol to complete the treatment steps of pharmaceutical wastewater.

[0080] Example 4

[0081] A method for preparing a porous biochar adsorption material for water purification comprises the following steps:

[0082] Primary heat treatment: Wash wolfberries three times with deionized water and then dry them in a vacuum drying oven at 60°C overnight. Mix wolfberries and the template reagent A prepared in Preparation Example 2, place them in a crucible, and then transfer them to a tube furnace. Under a nitrogen atmosphere, heat the mixture at a rate of 5°C / min to 680°C and pyrolyze for 45 minutes. It should be noted that during the primary heat treatment, the amount of MnCl2 added to the template reagent A needs to be controlled so that the ratio of C:MnCl2·4H2O in the primary pyrolyzed biochar is (1:1).

[0083] Secondary heat treatment: The primary pyrolysis biochar obtained in the first step was allowed to cool to room temperature, and then mixed evenly with the template reagent B prepared in Preparation Example 3 and placed in a crucible. The mixture was then transferred to a tube furnace and heated to 880°C at a rate of 5°C / min under a nitrogen atmosphere. The mixture was then pyrolyzed for 100 min. It should be noted that during the secondary heat treatment, the amount of ZnCl2 added to the template reagent B needed to be controlled so that the ratio of C:ZnCl2·4H2O in the secondary pyrolysis biochar was (1:0.2).

[0084] Washing and drying: The material after secondary heat treatment and calcination was washed with deionized water and 1 mol / L hydrochloric acid respectively to remove residual Zn and Mn until the pH of the supernatant was neutral, and then dried in a vacuum oven at 60°C overnight to prepare a porous biochar adsorption material for water purification with a porosity of 75.8%.

[0085] A method for treating pharmaceutical wastewater using a water purification porous biochar adsorption material comprises the following steps:

[0086] Take 1000mL of 20mg / L levofloxacin solution, add 150mg of potassium persulfate, stir and mix to obtain a mixed solution, then add the water purification porous biochar adsorption material to the mixed solution at an addition amount of 45mg / L, stir and mix, and quench with 2mL of methanol to complete the treatment steps of pharmaceutical wastewater.

[0087] Example 5

[0088] A method for preparing a porous biochar adsorption material for water purification comprises the following steps:

[0089] Primary heat treatment: Wash wolfberries three times with deionized water and then dry them in a vacuum drying oven at 60°C overnight. Mix wolfberries and the template reagent A prepared in Preparation Example 2, place them in a crucible, and then transfer them to a tube furnace. Under a nitrogen atmosphere, heat the mixture at a rate of 5°C / min to 680°C and pyrolyze for 45 minutes. It should be noted that during the primary heat treatment, the amount of MnCl2 added to the template reagent A needs to be controlled so that the ratio of C:MnCl2·4H2O in the primary pyrolyzed biochar is (1:1).

[0090] Secondary heat treatment: The primary pyrolysis biochar obtained in the first step was allowed to cool to room temperature, then mixed evenly with ZnCl2·4H2O and placed in a crucible. The mixture was then transferred to a tube furnace and heated to 880°C at a rate of 5°C / min under a nitrogen atmosphere. The mixture was then pyrolyzed for 100 min. It should be noted that during the secondary heat treatment, the amount of ZnCl2 powder added needed to be controlled so that the C:ZnCl2·4H2O ratio in the secondary pyrolysis biochar was (1:0.2).

[0091] Washing and drying: The material after secondary heat treatment and calcination was washed with deionized water and 1 mol / L hydrochloric acid respectively to remove residual Zn and Mn until the pH of the supernatant was neutral, and then dried in a vacuum oven at 60°C overnight to prepare a porous biochar adsorption material for water purification with a porosity of 75.8%.

[0092] A method for treating pharmaceutical wastewater using a water purification porous biochar adsorption material comprises the following steps:

[0093] 150 mg of potassium persulfate was added to 1000 mL of 20 mg / L levofloxacin solution, and the mixture was stirred to obtain a mixed solution. Then, the water purification porous biochar adsorption material was added to the mixed solution at an addition amount of 45 mg / L, and the mixture was stirred and quenched with 2 mL of methanol to complete the treatment steps of the pharmaceutical wastewater.

[0094] Example 6

[0095] Primary heat treatment: Wash wolfberries three times with deionized water and dry them in a vacuum drying oven at 60°C overnight. Mix wolfberries and MnCl2·4H2O powder evenly and place them in a crucible. Transfer the mixture to a tube furnace and heat the mixture to 680°C at a rate of 5°C / min under a nitrogen atmosphere. Pyrolysis is then carried out for 45 minutes. It should be noted that during the primary heat treatment, the amount of MnCl2 powder added must be controlled to ensure that the ratio of C to MnCl2·4H2O in the primary pyrolysis biochar is 1:1.

[0096] Secondary heat treatment: The primary pyrolysis biochar obtained in the first step was allowed to cool to room temperature, and then mixed evenly with the template reagent B prepared in Preparation Example 3 and placed in a crucible. The mixture was then transferred to a tube furnace and heated to 880°C at a rate of 5°C / min under a nitrogen atmosphere. The mixture was then pyrolyzed for 100 min. It should be noted that during the secondary heat treatment, the amount of ZnCl2 added to the template reagent B needed to be controlled so that the ratio of C:ZnCl2·4H2O in the secondary pyrolysis biochar was (1:0.2).

[0097] Washing and drying: The material after secondary heat treatment and calcination was washed with deionized water and 1 mol / L hydrochloric acid respectively to remove residual Zn and Mn until the pH of the supernatant was neutral, and then dried in a vacuum oven at 60°C overnight to prepare a porous biochar adsorption material for water purification with a porosity of 75.8%.

[0098] A method for treating pharmaceutical wastewater using a water purification porous biochar adsorption material comprises the following steps:

[0099] Take 1000mL of 20mg / L levofloxacin solution, add 150mg of potassium persulfate, stir and mix to obtain a mixed solution, then add the water purification porous biochar adsorption material to the mixed solution at an addition amount of 45mg / L, stir and mix, and quench with 2mL of methanol to complete the treatment steps of pharmaceutical wastewater.

[0100] Example 7

[0101] A method for preparing a porous biochar adsorption material for water purification comprises the following steps:

[0102] Primary heat treatment: Wash wolfberries three times with deionized water and then dry them in a vacuum drying oven at 60°C overnight. Mix wolfberries and the template reagent B prepared in Preparation Example 3, place them in a crucible, and then transfer them to a tube furnace. Under a nitrogen atmosphere, heat the mixture to 680°C at a rate of 5°C / min and pyrolyze for 45 minutes. It should be noted that during the primary heat treatment, the amount of ZnCl2 added to the template reagent A needs to be controlled so that the ratio of C:ZnCl2·4H2O in the primary pyrolysis biochar is (1:1).

[0103] Secondary heat treatment: The primary pyrolysis biochar obtained in the first step was allowed to cool to room temperature, and then mixed evenly with the template reagent A prepared in Preparation Example 2 and placed in a crucible. The mixture was then transferred to a tube furnace and heated to 880°C at a rate of 5°C / min under a nitrogen atmosphere. The mixture was then pyrolyzed for 100 min. It should be noted that during the secondary heat treatment, the amount of MnCl2 added to the template reagent B needed to be controlled so that the ratio of C:MnCl2·4H2O in the secondary pyrolysis biochar was (1:0.2).

[0104] Washing and drying: The material after secondary heat treatment and calcination was washed with deionized water and 1 mol / L hydrochloric acid respectively to remove residual Zn and Mn until the pH of the supernatant was neutral, and then dried in a vacuum oven at 60°C overnight to prepare a porous biochar adsorption material for water purification with a porosity of 75.8%.

[0105] A method for treating pharmaceutical wastewater using a water purification porous biochar adsorption material comprises the following steps:

[0106] Take 1000mL of 20mg / L levofloxacin solution, add 150mg of potassium persulfate, stir and mix to obtain a mixed solution, then add the water purification porous biochar adsorption material to the mixed solution at an addition amount of 45mg / L, stir and mix, and quench with 2mL of methanol to complete the treatment steps of pharmaceutical wastewater.

[0107] Comparative Example 1

[0108] A method for preparing a porous biochar adsorption material for water purification comprises the following steps:

[0109] The wolfberry was washed three times with deionized water and then dried in a vacuum drying oven at 60°C overnight. The wolfberry and MnCl2·4H2O powder were mixed evenly and placed in a crucible. The mixture was then transferred to a tube furnace and heated to 680°C at a rate of 5°C / min under a nitrogen atmosphere. The mixture was then pyrolyzed for 45 minutes. It should be noted that during the heat treatment process, the amount of MnCl2 powder added needed to be controlled so that the C:MnCl2·4H2O ratio in the pyrolyzed biochar was (1:1).

[0110] Washing and drying: The heat-treated and calcined material was washed with deionized water and 1 mol / L hydrochloric acid respectively to remove residual Mn until the pH of the supernatant was neutral, and then dried in a vacuum oven at 60°C overnight to prepare a porous biochar material.

[0111] A method for treating pharmaceutical wastewater using porous biochar material comprises the following steps:

[0112] 150 mg of potassium persulfate was added to 1000 mL of 20 mg / L levofloxacin solution, and the mixture was stirred to obtain a mixed solution. Then, the water purification porous biochar adsorption material was added to the mixed solution at an addition amount of 45 mg / L, and the mixture was stirred and quenched with 2 mL of methanol to complete the treatment steps of the pharmaceutical wastewater.

[0113] Comparative Example 2

[0114] A method for preparing a porous biochar adsorption material for water purification comprises the following steps:

[0115] The wolfberries were washed three times with deionized water and then dried overnight in a vacuum drying oven at 60°C. The wolfberries and ZnCl2·4H2O were mixed evenly and placed in a crucible. The mixture was then transferred to a tube furnace and heated to 880°C at a rate of 5°C / min under a nitrogen atmosphere. The mixture was then pyrolyzed for 100 minutes. It should be noted that the amount of ZnCl2 powder added during the heat treatment process was controlled to achieve a C:MnCl2·4H2O ratio of 1:0.2 in the pyrolyzed biochar.

[0116] Washing and drying: The heat-treated and calcined material was washed with deionized water and 1 mol / L hydrochloric acid respectively to remove residual Zn until the pH of the supernatant was neutral, and then dried in a vacuum oven at 60°C overnight to prepare the biochar material.

[0117] A method for treating pharmaceutical wastewater using biochar material comprises the following steps:

[0118] 150 mg of potassium persulfate was added to 1000 mL of 20 mg / L levofloxacin solution, and the mixture was stirred to obtain a mixed solution. Then, the water purification porous biochar adsorption material was added to the mixed solution at an addition amount of 45 mg / L, and the mixture was stirred and quenched with 2 mL of methanol to complete the treatment steps of the pharmaceutical wastewater.

[0119] Comparing the technical solutions of Examples 1-3 and Comparative Examples 1-2, the following viewpoints can be further illustrated with reference to the accompanying drawings:

[0120] Combined with Comparative Examples 1-2 Figure 4-5 , first in Figure 4 and Figure 5 It can be seen that the biochar material prepared in Comparative Example 1 presents an irregular and smooth surface flower-like morphology, and the surface of the biochar material prepared in Comparative Example 2 is a pore structure of uniform size, indicating that the single template reagent ZnCl2 has the etching pore-forming performance, while the single template reagent MnCl2 has no etching pore-forming ability.

[0121] Combined with Examples 1-3 and Figure 1-2 It can be seen that the biochar material prepared in this application shows a significant increase in the number of pores, and is accompanied by the presence of pores / cavities with different radii, indicating that this application can effectively improve the surface porosity of the biochar material after embedding the dual template reagent into the biochar. Figure 3 It can be seen that the graphene layers are disordered, uneven in thickness, and have obvious oriented multilayer regions, which is a unique graphite microcrystal morphology. In addition, there are circular gaps in multiple regions, which are attributed to the macroporous structure caused by the combined action of the dual template reagents. Finally, combined with Figure 6 The EDS mapping results are shown, indicating that C, O, Cl, Mn, and Zn are uniformly distributed.

[0122] Combine Figure 7 It can be seen from the technical solutions of Examples 1-3 and Comparative Examples 1-2 that Example 1 of the present application has a higher activation efficiency, indicating that the addition of the dual-template reagent greatly improves the effect of biochar and can achieve 92.7% LEVO degradation within 60 minutes.

[0123] Combine Figure 7 Compared with Examples 5, 6 and 7, Example 5 does not use template reagent B, and the directly mixed ZnCl2 powder lacks graphene confinement during secondary pyrolysis, resulting in Zn volatilization and agglomeration, increased metal residue, and reduced degradation efficiency;

[0124] In Example 6, because Mn was not pre-loaded onto graphene during the primary pyrolysis, the MnO2 particles generated by direct pyrolysis of MnCl2 mixed with biomass were too large, hindering the penetration of the Zn etchant, resulting in a single pore structure and poor degradation efficiency.

[0125] In Example 7, ZnCl2 is loaded first and then MnCl2 is introduced. In the secondary high-temperature stage, Zn preferentially volatilizes and etches the carbon layer, destroying the anchoring points of subsequent Mn species, resulting in Mn volatilization loss. At the same time, the lack of Zn-Mn synergistic effect leads to a decrease in defect density and a significant reduction in degradation efficiency.

[0126] Finally, a comparison was made between the technical solutions of Examples 1-3 and Example 4. The degradation efficiency of the biochar materials prepared by the template reagents A and template reagents B prepared in Example 4 was significantly improved, and 95.4% LEVO degradation was achieved within 60 minutes. This further illustrates that the technical solution of the present application optimizes the structures of template reagents A and template reagents B, and selects three-dimensional porous graphene foam particles as dispersed coating carriers to uniformly disperse zinc chloride and manganese chloride in the biochar system. The porous biochar adsorption material has rich pore structures and active sites through water purification, and can adsorb drug molecules to the biochar surface through physical adsorption and chemical adsorption, thereby promoting the rapid achievement of adsorption equilibrium, shortening the adsorption time, and improving the treatment efficiency, further reflecting its synergistic effect with zinc ions and manganese ions in adsorption performance.

[0127] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A porous biochar adsorption material for water purification, characterized in that: The porous biochar particles include porous biochar particles with a porosity of 70-85%, wherein the porous biochar particles include porous biochar particles doped with Zn ions and Mn ions; The method for preparing the porous biochar adsorption material for water purification comprises the following preparation steps: Primary heat treatment: washing and drying the biochar raw material, mixing it with the template reagent A and placing it in a pyrolysis device, and collecting the primary pyrolysis biochar after the primary pyrolysis treatment; Secondary heat treatment: take the primary pyrolysis biochar, mix it with the template reagent B, and place it in a pyrolysis device. The secondary pyrolysis biochar is collected for secondary pyrolysis treatment; Washing and drying: washing the secondary pyrolysis biochar material to remove soluble metal elements, and then drying to prepare a porous biochar adsorption material for water purification; The template reagent A includes MnCl2 powder, and the C in the primary pyrolysis biochar is MnCl 2· 4H2O=(1:0-1.0), where MnCl 2· 4H2O cannot take 0; The template reagent B includes ZnCl2 powder, and the secondary pyrolysis biochar contains C:ZnCl2·4H2O=(1:0-2), wherein ZnCl2·4H2O cannot be 0; The template reagent A and the template reagent B are both provided with a dispersion coating carrier, and the dispersion coating carrier includes three-dimensional porous graphene foam particles.

2. The porous biochar adsorption material for water purification according to claim 1, characterized in that: The relative proportion of the C element in the porous biochar adsorption material for water purification is ≤93.15%, and the relative proportion of the O element is ≥5.46%.

3. The method for preparing a porous biochar adsorption material for water purification according to claim 1, characterized in that: The template reagent A is prepared using the following scheme: After surface activation treatment of three-dimensional porous graphene foam particles, they are washed, dried, and immersed in a MnCl2-N,N-dimethylformamide solution. After magnetic stirring, they are vacuum-dried and placed in a reaction furnace. Under the protection of inert gas, the temperature is increased and kept warm, and the particles are ground and sieved to prepare a template reagent A.

4. The method for preparing a porous biochar adsorption material for water purification according to claim 1, characterized in that: The template reagent B is prepared using the following scheme: After surface activation treatment of three-dimensional porous graphene foam particles, they are washed, dried, and immersed in a ZnCl2-N,N-dimethylformamide solution. After magnetic stirring, they are vacuum-dried and placed in a reaction furnace. Under the protection of inert gas, the temperature is increased and kept warm, and the particles are ground and sieved to prepare template reagent B.

5. The method for preparing a porous biochar adsorption material for water purification according to claim 1, characterized in that: The three-dimensional porous graphene foam particles are made using the following technical solution: A graphene oxide dispersion and polystyrene microspheres are stirred and mixed, hydrazine hydrate is added dropwise and stirred, the temperature is increased and pressure is applied, the filter cake is filtered and collected, the filter cake is placed in a toluene solution, stirred and mixed, and rinsed with deionized water, vacuum dried, ground and dispersed to prepare three-dimensional porous graphene foam particles.

6. A method for treating pharmaceutical wastewater using the porous biochar adsorption material for water purification according to any one of claims 1-2, characterized in that: The following steps are involved: After adding persulfate to the wastewater to be treated, add the water purification porous biochar adsorption material and stir at room temperature; After adding a quenching agent for quenching treatment, the wastewater degradation treatment can be completed.

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