Al / C composite material based on elm template and preparation method thereof, and application of Al / C composite material to adsorption of copper ions in sewage
The Al/C composite material prepared by using elm seed templates, which combines a porous carbon framework and active aluminum sites, solves the problems of high cost and low efficiency of existing adsorbents, achieves efficient removal of copper ions from water, and realizes the dual benefits of waste utilization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-05
- Publication Date
- 2026-03-27
AI Technical Summary
Existing adsorbents are costly, inefficient, and complex to treat copper-containing wastewater. Biochar and activated alumina each have problems such as poor adsorption selectivity and difficulty in regeneration, making it difficult to meet the needs of deep treatment of high-concentration copper-containing wastewater.
Al/C composite materials were prepared using elm seed templates. The elm seeds were carbonized at high temperature to form a porous carbon skeleton, which was then mixed with aluminum chloride and calcined at high temperature to form a synergistic structure between the porous carbon skeleton and active aluminum sites, thereby enhancing the adsorption performance.
It achieves low-cost and high-efficiency copper ion adsorption, with a small adsorption dose and strong adsorption capacity, and a removal rate of up to 91.3%, meeting the needs of industrial applications, while solving the environmental pollution problem of elm leaves.
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Figure CN121732136A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of environmental protection and water treatment, and particularly relates to an Al / C composite material based on yuxian templates and a preparation method and application thereof in adsorbing copper ions in wastewater. BACKGROUND
[0002] Urbanization, industrialization and agricultural activities have led to more and more metal resources being mined, processed and used. Copper is one of the most valuable and most commonly used heavy metals. Mining, steel, metallurgy, chemical manufacturing, electroplating, printing, circuit, paint, plastic and etching, chemical fertilizer, pesticide and other industries will produce a large amount of copper-containing wastewater. Copper ions are soluble, easy to complex, and can undergo redox reactions and cannot be degraded, thus having environmental persistence, biological toxicity and accumulation and amplification along the food chain. Untreated copper-containing wastewater directly or indirectly discharged into the environment will seriously pollute the water environment, threaten the safety of water resources and water ecology, and cause harm to human health. Like other heavy metals, copper exists in the form of hydrated ions in river water and other water environments. Although copper is one of the essential nutrients for organisms, excessive exposure or intake of copper by organisms will cause toxicity. High concentrations of copper will interfere with the sensory system of fish, affecting the predation, growth and migration of fish. Copper can also cause toxic symptoms in humans, such as nausea, vomiting, stomach cramps, gastrointestinal discomfort, convulsions, seizures, diarrhea, jaundice, etc. Heavy metal copper has the risk of causing cancer, which can cause damage to the nervous system, kidney failure and gastrointestinal bleeding, and high concentrations of copper are even fatal.
[0003] Current copper-containing wastewater treatment technologies include traditional treatment processes and new treatment methods. The former includes chemical precipitation, complexation, flotation, ion exchange and coagulation flocculation. New treatment methods include membrane filtration technology, adsorption method, electrochemical method, photocatalytic process and the integration of nanotechnology. Compared with the above technologies, adsorption stands out due to its selective adsorption, low cost, simplicity, recyclability and strong adsorption capacity. The adsorbent plays a crucial role in the adsorption process.
[0004] Biochar is a kind of carbon derived from biomass pyrolysis, which has been widely studied due to its low cost and environmental friendliness. Biochar has many advantages as a carrier. First, biochar has well-developed pores, certain activity, and adsorption capacity, which meet the general characteristics of an excellent carrier. Second, biochar is widely available and low-cost, mainly using waste, which is eco-friendly. Various biomass resources such as crop straw, rice husk, tea residue, bone, bagasse, vegetables, and other biological waste can be utilized. Third, the carrier has strong loading capacity and can effectively combine with aluminum and other doping elements to form a carbon-loaded multi-doped copper removal agent, which can play various synergies and enhance its copper removal performance. Therefore, biochar loaded with aluminum-based doped materials has become a research hotspot in the development of environmentally friendly materials for removing copper ions and other harmful substances in water.
[0005] Celtis tetrandra is not only a common greening tree species, but also a seasonal delicacy that people love to eat, often made into steamed dishes and porridge. At the same time, Celtis tetrandra fruit can also be processed into jam and preserved fruit. However, these processing processes often produce a large amount of by-product - Celtis tetrandra leaves, which account for about 30% to 40% of the available part of the whole plant. Chemical analysis shows that fresh Celtis tetrandra leaves are rich in protein, vitamins, minerals and other nutrients, and also contain flavonoids, polysaccharides and other functional compounds, as well as various antioxidant active substances. However, Celtis tetrandra leaves are prone to rot and spoilage, and if not properly handled, they will become a source of environmental pollution. From another perspective, fine utilization of Celtis tetrandra leaves is expected to develop high-value products or raw materials in the fields of food additives, natural medicines, and biological materials.
[0006] With the continuous development of Celtis tetrandra fruit processing industry, a large amount of Celtis tetrandra leaves are produced due to the lack of stable and effective disposal methods, which has become a difficult problem to be solved. Currently, the disposal methods of Celtis tetrandra leaves are mainly direct incineration, random disposal or simple composting, which not only causes air pollution and soil pollution, but also breeds mosquitoes and spreads bacteria. Although some researchers have explored the application of Celtis tetrandra leaves in biological feed and plant fertilizer, the related achievements have not formed large-scale and industrialization, and the application of Celtis tetrandra leaves in environmental remediation such as adsorption of heavy metals and purification of water is even less reported.
[0007] Activated carbon can capture copper ions by physical adsorption due to its developed pore structure and large specific surface area. The functional groups on its surface can also undergo ion exchange and complexation reactions with copper ions, improving the adsorption effect. However, ordinary activated carbon has poor selectivity for copper ions, and it is difficult to regenerate after adsorption saturation, usually requiring high-temperature or chemical reagent treatment, which is costly and limits large-scale application. Activated alumina is often used in industrial wastewater copper removal due to its good chemical stability and high mechanical strength. However, this technology has high cost and low adsorption capacity, and the preparation process requires high-temperature calcination and acid-base activation, which consumes a lot of energy. Moreover, the adsorption rate is slow, and secondary pollution may occur during regeneration, limiting its popularization. Ion exchange resins contain specific functional groups that can undergo selective ion exchange reactions with copper ions. Strongly acidic cation exchange resins have strong affinity for copper ions and can efficiently remove low-concentration copper-containing wastewater. However, the resin is expensive, susceptible to interference from other ions in the solution, and requires frequent regeneration, consuming a large amount of acid and base reagents, resulting in high operating costs.
[0008] Although simple biochar materials have abundant pore structure and large specific surface area, their adsorption capacity for copper is not satisfactory. Due to the limited types of surface functional groups and active sites, the combination of biochar and copper ions mainly relies on physical adsorption, with weak chemical adsorption, resulting in generally low adsorption capacity, which cannot meet the demand for deep treatment of high-concentration copper-containing wastewater. In addition, biochar has poor selectivity for copper ions and is easily interfered by other coexisting ions in the solution, greatly reducing the actual application effect.
[0009] Many biochar materials modified by conventional metal salts have improved adsorption capacity for copper ions to some extent, but the improvement in adsorption capacity still cannot meet the stringent standards of industrial wastewater treatment. During conventional modification, the combination efficiency of metal salts and biochar surface functional groups is low, and a large number of metal ions cannot be effectively loaded, resulting in resource waste. At the same time, the stability of the modified material is poor, and metal ions are easily dissolved during adsorption and regeneration, which not only affects the adsorption effect but also may cause secondary pollution. In addition, the existing modification process adopts a step-by-step operation process of high-temperature pyrolysis carbonization-metal modification, which requires multiple high-temperature treatments and complex chemical reagent addition, consuming a large amount of energy and chemical reagents, prolonging the preparation period, and greatly increasing the production cost. These defects seriously restrict the large-scale application of modified biochar materials in copper-containing wastewater treatment.
[0010] Therefore, in view of the existing adsorption Cu 2+ The technical cost is high, the efficiency is low, and the process is complex. Therefore, it is an urgent problem to provide a new composite material for adsorbing copper ions in wastewater. SUMMARY
[0011] In view of this, the Al / C composite material based on elm money template and a preparation method and application thereof for adsorbing copper ions in sewage are provided to construct a porous carbon framework-active aluminum site synergistic structure, and realize low-cost, low-energy consumption and high adsorption performance synergistic optimization.
[0012] The technical scheme provided by the present application is: a preparation method of an Al / C composite material based on an elm money template, comprising:
[0013] The biological charcoal powder is prepared by carbonizing fresh elm money at high temperature, grinding and sieving;
[0014] The biological charcoal powder, aluminum chloride powder and deionized water are stirred and mixed, and then subjected to centrifugal treatment, and after the centrifugal treatment is completed, the supernatant is removed, and the sample is repeatedly washed.
[0015] After washing, the sample is dried, and then subjected to high-temperature calcination to obtain the Al / C composite material.
[0016] Preferably, the fresh elm money is carbonized at a high temperature of 600 DEG C, and the obtained biological charcoal is ground and sieved to obtain biological charcoal powder with a particle size of less than 74 microns.
[0017] Preferably, the biological charcoal powder, aluminum chloride powder and deionized water are mixed at a mass ratio of 3.5:0.3:100.
[0018] Preferably, the centrifugal treatment has a parameter of 8000 r / min for 15 min.
[0019] Preferably, the washing process is: first washing once with deionized water, and then washing twice with anhydrous ethanol.
[0020] Preferably, after washing, the sample is placed in a constant-temperature drying box at 80 DEG C for drying, and then subjected to high-temperature calcination at 600 DEG C to obtain the Al / C composite material.
[0021] The present application also provides an Al / C composite material based on an elm money template prepared by the above preparation method.
[0022] Finally, the Al / C composite material provided by the present application is also applied to remove Cu 2+ from sewage.
[0023] The preparation method of the Al / C composite material based on the elm money template provided by the present application has controllable preparation process, shorter preparation time, lower energy consumption, and adjustable components of the prepared adsorbent;
[0024] The Al / C composite material prepared by the present application has excellent adsorption performance, high Cu 2+ removal efficiency and low use cost, and the adsorbent of the present application can remove Cu2+ The removal rate is up to 91.3%, which meets the general Cu removal 2+ Compared with traditional alumina, the Al / C composite material has a smaller dosage and a stronger adsorption capacity. The Al / C composite material is a synergistic structure of "porous carbon framework + active aluminum sites". The porous carbon framework formed by the carbonization of yumei nuts provides a large number of adsorption sites and increases the contact area. The active aluminum converted during the sintering of aluminum chloride can not only adsorb Cu 2+ by electrostatic adsorption, but also can combine Cu 2+ by coordination complexation and ion exchange. The adsorption mechanism of the combination of the two is more abundant than the adsorption mode of single alumina, and has a stronger adsorption capacity. BRIEF DESCRIPTION OF DRAWINGS
[0025] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate an embodiment consistent with the present application and, together with the description, serve to explain the principles of the application.
[0026] Figure 1 An SEM image of the Al / C composite material based on yumei nut templates provided by the present application; DETAILED DESCRIPTION
[0027] The present application will be further explained in conjunction with specific embodiments, but is not limited to the present application.
[0028] The present application is directed to the existing adsorption Cu 2+ removal technology, which has high cost, low efficiency and complex process. The present embodiment first provides a preparation method of Al / C composite material using yumei nuts as templates, which comprises the following steps:
[0029] Step 1: Fresh yumei nuts are washed clean in a beaker with deionized water, dried, and then placed in a muffle furnace for high-temperature carbonization at 550-650℃. Then the obtained biochar is ground and sieved through a 200-mesh sieve to obtain a powder. Preferably, the particle size of the biochar powder is less than 74μm. The carbonization temperature is preferably 600℃, which can balance the "carbon framework pore development" and "aluminum site activity", and can ensure the material structure and adsorption performance at the same time. If the temperature is too low, the yumei nuts will not be carbonized sufficiently, the pore structure of the carbon framework will be less, and the active sites will be insufficient. If the temperature is too high, the carbon framework will be easy to collapse, and the active sites of the aluminum-based compound may be reduced due to excessive sintering.
[0030] Step 2: The obtained biochar powder and aluminum chloride powder are mixed with deionized water in a mass ratio of 3.5:0.3:100, and then stirred and mixed for 12h. The proportion of deionized water is adjusted according to the solid-liquid mixing requirements. The above proportion can avoid the following situations:
[0031] Too much biochar: insufficient loading of aluminum sites, and few active groups for adsorbing copper ions;
[0032] Too much aluminum chloride: easy to agglomerate and block the pores of the carbon skeleton, thereby reducing the contact area;
[0033] The optimal ratio of the carbon skeleton pores and the aluminum site loading is preferably 3.5:0.3:100 (mass ratio) of the biochar powder, the aluminum chloride powder and the deionized water, which can maximize the adsorption efficiency.
[0034] The elm nuts are widely available: in spring, elm trees are widely distributed in urban and rural areas, whether they are urban green belts, rural forests, or courtyard-planted elm trees, a large number of elm nuts can be easily obtained, fully realizing efficient recycling of natural resources, the aluminum source is also common and low in cost, fully reducing the production cost, and realizing high-value utilization of biological waste.
[0035] Step 3: The uniformly stirred mixed solution obtained in step 2 is transferred to a centrifugal device for centrifugal treatment; preferably, centrifugation is performed at a speed of 8000 r / min for 15 min.
[0036] Step 4: After centrifugation, the supernatant is removed, and the sample is repeatedly washed with deionized water and ethanol; preferably, the washing step is washing once with deionized water and twice with anhydrous ethanol.
[0037] Step 5: The washed sample in step 4 is transferred to a clean container and placed in a drying oven at 80℃ for 12h.
[0038] Step 6: The dried product is placed in a muffle furnace and calcined at 600℃ to obtain the Al / C composite material.
[0039] First, the elm nuts are carbonized to decompose the organic matter in the elm nuts and form a porous carbon skeleton, providing a large number of adsorption sites; after mixing and stirring, the aluminum chloride is dissolved, and the aluminum ions therein are adsorbed on the surface of the carbon skeleton; combined with the subsequent secondary calcination, the aluminum ions are converted into active aluminum-based compounds at high temperature, and the carbon skeleton is further stabilized; finally, a structure of "porous carbon (physical adsorption) + active aluminum (chemical adsorption / complexation)" is formed, and the two adsorption mechanisms work together, so the adsorption effect is better.
[0040] The composite material prepared by the above preparation method can effectively treat Cu 2+ pollution problems while effectively avoiding environmental pollution problems caused by natural decay of elm nuts, turning waste into treasure to produce high-value adsorption materials, and achieving targeted treatment of copper pollution in water bodies, achieving dual benefits of ecological protection and pollution treatment. In order to further illustrate the present application, the present application will be further described in detail in conjunction with the examples.
[0041] Example 1
[0042] Step 1: Take fresh elm money and clean it, dry it and put it in the muffle furnace at 600℃ for carbonization, grind the obtained biochar and pass it through a 200 mesh sieve to obtain a powder;
[0043] Step 2: Mix the obtained biochar powder (particle size < 74 μm) and aluminum chloride powder with deionized water in a mass ratio of 3.5:0.3:100, then stir for 12 h;
[0044] Step 3: Transfer the mixed solution obtained in step 2 to a centrifuge device and centrifuge at a speed of 8000 r / min for 15 min;
[0045] Step 4: After centrifugation, remove the supernatant, wash the sample once with deionized water, and then wash twice with anhydrous ethanol;
[0046] Step 5: Transfer the washed sample in step 4 to a clean culture dish and place it in an 80℃ oven for drying for 12 h;
[0047] Step 6: Put the dried product in step 5 into a muffle furnace at 600℃ for high-temperature firing to obtain an Al / C composite material P01 using elm money as a biological template.
[0048] The application of an Al / C composite material using elm money as a template in copper removal in water treatment, the P01 sample prepared by the above method was placed in a solution with an initial concentration of 300 mg / L, 500 mg / L, and 700 mg / L of copper ions, respectively, for adsorption determination, under the condition of an adsorbent dosage of 0.18 g / L, the copper removal rate of the sample can reach 91.3%, 88.9%, and 88.7%, respectively, and the experimental adsorption capacity can reach 1512.67 mg / g, 2469.44 mg / g, and 3449.44 mg / g, respectively.
[0049] Traditional alumina adsorbs Cu 2+ Mainly by surface electrostatic adsorption, but the Al / C composite material of the present embodiment is a synergistic structure of "porous carbon skeleton + active aluminum sites":
[0050] The porous carbon skeleton formed by carbonization of elm money provides a large number of adsorption sites and increases the contact area;
[0051] The active aluminum converted in the firing of aluminum chloride not only can electrostatically adsorb Cu 2+ , but also can combine Cu 2+ through coordination complexation and ion exchange;
[0052] The combined adsorption mechanism is more abundant than the adsorption mode of single alumina, so the adsorption capacity is stronger.
[0053] For example, Figure 1The SEM image shows that there are abundant pores, wrinkles and uneven textures on the surface of the material, which directly proves that the loose carbon skeleton structure is successfully constructed after the yuxian template carbonization, which is the structural basis for the material to provide a large number of adsorption sites.
[0054] The inherent microstructure of yuxian leaf endows biochar with high surface energy, and the composite material forms a micro-porous hierarchical structure after sintering. Such complex porous hierarchical structure greatly improves the effective surface exposure of the material, proving that the composite material has a high specific surface area and surface energy. High surface energy significantly improves the activity of the material surface atoms, reduces the adsorption energy barrier of Cu 2+ , and provides thermodynamic and kinetic convenience for the rapid adsorption and retention of pollutant ions. The synergistic effect of porous skeleton and uniform active sites together builds the core structural conditions for high-efficiency adsorption of the material.
[0055] At the same time, no agglomerated particles of aluminum-based components are observed in the SEM image, indicating that the active aluminum sites are uniformly dispersed on the surface of the carbon skeleton, avoiding the reduction of adsorption efficiency caused by site aggregation. The microstructure of "porous carbon skeleton + active site" is the core reason why the material can achieve high adsorption capacity and high removal rate.
[0056] In this embodiment, fresh yuxian is used as raw material, carbonized at 600℃, and ground through a 200 mesh sieve (particle size < 74μm) to ensure a large specific surface area of the carbon skeleton. In the step, the biochar and aluminum chloride are directly mixed and stirred, and the active aluminum sites are loaded after one centrifugation, washing and two sintering processes. The process is simple and uniform.
[0057] Comparative Example 1
[0058] The application of a nitrogen-modified biochar for the adsorption of copper ions in wastewater specifically includes the following steps:
[0059] Step 1: Wash the rice straw to remove surface impurities, dry it, and then weigh a certain amount into a quartz boat and place it in a 700℃ tube furnace for pyrolysis. The entire pyrolysis process is protected by nitrogen gas. After cooling to room temperature, take it out;
[0060] Step 2: Weigh 5g of pyrolyzed straw biochar and 6g of urea into a beaker, add 100mL of pure water, and stir in a magnetic stirrer for 24h. After drying at 80℃, a mixture is obtained;
[0061] Step 3: Place the mixture in a muffle furnace and pyrolyze at 700℃ for 2h. After cooling to room temperature, take out the nitrogen-modified biochar;
[0062] Step 4: Wash the nitrogen-modified biochar with pure water until it is neutral, then dry it and ball mill for 1min to obtain a uniformly granulated biochar with a particle size range of 180~125μm.
[0063] The application of the composite material obtained in Comparative Example 1 in water treatment for removing copper ions, with initial concentrations of copper ions being 10 mg / L, 30 mg / L, and 50 mg / L, respectively, and the adsorbent dosage being 0.15 g / L, the copper removal rates are 90.5%, 58.83%, and 60.94%, respectively, and the experimental adsorption capacities are 60.33 mg / g, 117 mg / g, and 203.13 mg / g, respectively.
[0064] In Comparative Example 1, the straw biochar modified by nitrogen: only relying on the physical adsorption of the carbon skeleton + weak complexation of a small amount of nitrogen-containing functional groups, and the nitrogen modification does not introduce specific adsorption of Cu 2+ active components, and the copper removal rate is only 60.94%;
[0065] In addition, in the preparation steps in Comparative Example 1, 700°C tube furnace pyrolysis + nitrogen protection is required, which has high energy consumption compared to Example 1, and the biochar particle size is 180-125 μm, and the specific surface area is small.
[0066] Comparative Example 2
[0067] A preparation method of a pomelo peel biochar adsorbent, specifically comprising the following steps:
[0068] Step 1: The pomelo peel is cut into pieces, dried and crushed, and then passed through a 20-mesh sieve to obtain pomelo peel powder;
[0069] Step 2: The pomelo peel powder obtained in Step 1 is placed in a ceramic crucible and carbonized at 300°C for 6 hours in a muffle furnace;
[0070] Step 3: After carbonization, the muffle furnace is naturally cooled, and the pomelo peel is taken out and soaked in dilute hydrochloric acid for 12 hours;
[0071] Step 4: The pomelo peel is washed with distilled water until it is neutral, and then dried to obtain a pomelo peel biochar adsorbent;
[0072] The application of the composite material obtained in Comparative Example 2 in water treatment for removing copper, with an initial concentration of copper ions being 20 mg / L and an adsorbent dosage being 2.5 g / L, the copper removal rate is 34.14%, and the experimental adsorption capacity is only 2.7312 mg / g.
[0073] In Comparative Example 2, the pomelo peel is used as biochar: the surface functional groups of the unmodified biochar are single, only relying on physical adsorption, and the pore development is poor, and the adsorption capacity is only 2.7312 mg / g.
[0074] In the above preparation steps, 300°C carbonization is used, and dilute hydrochloric acid soaking is also required, which has high process complexity.
[0075] Comparative Example 3
[0076] A preparation method of a potassium permanganate modified biochar material adsorbent, specifically comprising the following steps:
[0077] Step 1: Clean the corncob with deionized water and dry it, and then crush the dried corncob into small particles as much as possible;
[0078] Step 2: Put the small particles of corncob obtained in the first step into a muffle furnace, and carbonize them at 400°C for 2h under nitrogen protection;
[0079] Step 3: After the carbonization is completed, wait for the muffle furnace to cool down naturally, and then take out the biochar and wash it with a large amount of deionized water;
[0080] Step 4: Add potassium permanganate and biochar to deionized water in a mass ratio of 1:1, and stir at 100°C for 24h;
[0081] Step 5: Wash the precipitate with a large amount of deionized water, and dry it in a drying oven to obtain a potassium permanganate-modified biochar material adsorbent;
[0082] The composite material obtained in Comparative Example 3 was applied in copper removal in water treatment, and under the adsorption conditions of an initial copper ion concentration of 50mg / L and an adsorbent dosage of 0.1g / L, the copper removal rate was 45.87%, and the experimental adsorption capacity was 229.35mg / g.
[0083] In addition, the above steps require 100°C stirring for 24h, which is time-consuming.
[0084] Comparative Example 4
[0085] A method for preparing a magnetic biochar material adsorbent, specifically comprising the following steps:
[0086] Step 1: Add 1g of potassium permanganate-modified biochar, 1g of FeCl3•6H2O and 0.75g of FeC l3 •4H2O to deionized water;
[0087] Step 2: Take the mixture solution obtained in the first step, and adjust the pH value to 9.0 with 30% NH3•H2O;
[0088] Step 3: Stir the mixed solution at 90°C under nitrogen protection for 3h;
[0089] Step 4: Wash the suspension with a large amount of deionized water and vacuum dry to obtain a magnetic biochar adsorbent material;
[0090] The composite material obtained in Comparative Example 4 was applied in copper removal in water treatment, and under the adsorption conditions of an initial copper ion concentration of 50mg / L and an adsorbent dosage of 0.1g / L, the copper removal rate was 38.98%, and the experimental adsorption capacity was 194.9mg / g.
[0091] Comparative Example 4 needs to adjust pH to 9.0 + nitrogen protection, the operation is complex, and the modified component has weak binding force with the carbon skeleton, which is easy to lose in adsorption, resulting in performance decline.
[0092] Comparative Example 3 uses potassium permanganate to modify corn cob biochar, and Comparative Example 4 uses magnetic biochar: the main role of the modified component is to enhance the activity of the carbon skeleton or realize magnetic separation, and the adsorption capacity of Cu² + There is no specific adsorption capacity, and the adsorption is still mainly physical adsorption of the carbon skeleton, and the copper removal rate is only 45.87%.
[0093] From the perspective of raw materials, elm seeds are plant samaras, which naturally have a loose and porous microstructure, and after carbonization, uniform pores can be formed without additional activation, and they have a microstructure advantage:
[0094] Straw fibers are dense, and pomelo peels have loose and disordered structures, which need special treatment to improve porosity. After carbonization, the pores are easy to collapse or unevenly distributed, and additional activators such as urea in Comparative Example 1 and dilute hydrochloric acid in Comparative Example 2 need to be added, increasing the cost.
[0095] Elm seeds contain a small amount of lignin and pectin, which can help stabilize active aluminum sites during carbonization; straw cellulose has a high content, which is easy to shrink excessively at high temperatures; and pomelo peels contain a large amount of water and sugar, which are easy to produce tar and block pores during carbonization, all of which are not conducive to the loading of active components.
[0096] Elm seeds do not need complex pretreatment and can be directly carbonized after cleaning; straw needs to remove impurities and be crushed, and pomelo peels need to remove the pulp and degrease, which has many pretreatment steps and takes a long time.
[0097] After the active aluminum sites are combined with the carbon skeleton of elm seeds, both "high adsorption capacity" and "fast adsorption rate" can be met.
[0098] Straw-based biochar needs to be modified with nitrogen and potassium permanganate to improve adsorption, and pomelo peel-based biochar even after modification, the adsorption capacity is still very low, which cannot meet the demand of high-concentration copper-containing wastewater treatment.
[0099] The carbonization temperature of elm seeds is consistent with the secondary firing temperature, and there is no need to adjust the equipment parameters, which is low in energy consumption; while straw needs a higher carbonization temperature, and pomelo peels need low-temperature carbonization + acid washing, which has poor process compatibility, and both raw materials will increase the difficulty of industrial application.
[0100] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to include the preferred embodiments and all changes and modifications falling within the scope of the present application.
[0101] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.
Claims
1. A method for preparing Al / C composite materials based on elm seed templates, characterized in that, include: Fresh elm seeds were used as raw material. They were carbonized at high temperature, ground and sieved to obtain biochar powder. After mixing biochar powder, aluminum chloride powder, and deionized water, the mixture was centrifuged. After centrifugation, the supernatant was removed, and the sample was washed repeatedly. After washing, the sample is dried, and then fired again at high temperature to obtain the Al / C composite material.
2. The method for preparing Al / C composite material based on elm seed template according to claim 1, characterized in that, Fresh elm seeds were carbonized at 600℃, and the resulting biochar powder, after grinding and sieving, had a particle size of <74μm.
3. The method for preparing Al / C composite material based on elm seed template according to claim 1, characterized in that, The biochar powder, aluminum chloride powder, and deionized water are mixed in a mass ratio of 3.5:0.3:
100.
4. The method for preparing Al / C composite material based on elm seed template according to claim 1, characterized in that, The parameters for the centrifugation process are: centrifugation at 8000 r / min for 15 min.
5. The method for preparing Al / C composite material based on elm seed template according to claim 1, characterized in that, The washing process is as follows: first wash with deionized water once, then wash twice with anhydrous ethanol.
6. The method for preparing Al / C composite material based on elm seed template according to claim 1, characterized in that, After washing, the sample was placed in an 80℃ constant temperature drying oven to dry, and then fired at 600℃ to obtain the Al / C composite material.
7. The Al / C composite material based on elm seed template prepared by any one of the preparation methods according to claims 1-6.
8. The application of the composite material according to claim 7, characterized in that, The Al / C composite material is used in wastewater treatment to remove Cu. 2+ .