A method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 surface loading

Abstract

The application belongs to the field of photocatalysis, and particularly relates to a preparation method of ethylene tar-based composite photocatalytic spherical activated carbon loaded with TiO2. The spherical activated carbon is prepared by using high-temperature ethylene tar pitch and / or high-temperature coal tar as raw materials, adding one or more of cracked naphthalene distillate, anthracene oil, phenanthrene oil and indene oil as a blending solvent, and then performing the steps of mixing, crushing, Soxhlet extraction, mixing with polyvinyl alcohol solution, ultrasonic treatment, heating and stirring, shaping, drying, non-melting treatment, carbonization and KOH activation. The obtained spherical activated carbon is then impregnated with TiO2 to obtain the finished product. The blending solvent effectively reduces the viscosity of the system, optimizes the spheroidization and non-melting process, promotes the crosslinking reaction, and avoids sintering and excessive oxidation of the spherical body. The product has the characteristics of good sphericity, uniform particle size, high strength, large specific surface area, developed pore structure and excellent adsorption performance, and is suitable for high-end adsorption and catalysis fields.

Description

Technical Field

[0001] This invention belongs to the field of photocatalysis, and particularly relates to a method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 supported on its surface. Background Technology

[0002] Traditional powdered and granular activated carbon is increasingly facing bottlenecks in high-end industrial applications. Its irregular and angular shape leads to low packing density, high fluid resistance, and easy abrasion and pulverization. This not only easily clogs pipes and contaminates systems, but its poor mechanical strength also makes it difficult to withstand frequent adsorption-desorption cycles or harsh operating conditions, easily resulting in breakage and failure. In addition, its wide pore size distribution also limits its ability to efficiently and selectively adsorb molecules of specific sizes.

[0003] Therefore, the industry urgently needs a new type of activated carbon that combines high mechanical strength, regular morphology, and controllable pore size to achieve technological breakthroughs. Spherical activated carbon, due to its perfect geometric shape, can achieve high packing density, low flow resistance, excellent wear resistance, and uniform fluid distribution, making it an ideal research direction. However, traditional preparation processes often use high-softening-point pitch, which generally suffers from problems such as high impurities in raw materials, high viscosity, difficult processing, and low pelleting rate, hindering its industrial application. Furthermore, spherical activated carbon prepared from traditional coal tar pitch has a chemically inert surface and is predominantly microporous, which is detrimental to light absorption and reaction mass transfer. The impurities it contains may interfere with the catalytic process, and it is also easily photocorroded. These inherent characteristics make it difficult for it to serve as a highly efficient photocatalytic material as an adsorption carrier.

[0004] Against this backdrop, a novel process using ethylene tar pitch and anthracene oil blends as precursors demonstrates significant advantages. Viscosity regulation and plasticization modification of the pitch system with anthracene oil significantly improves the processing performance of the raw materials, resulting in a more stable pelletizing process and a significantly increased pelletizing rate. Simultaneously, the synergistic effect of the two helps form a more regular pore structure during subsequent activation, enabling directional control of pore size distribution and thus enhancing the adsorption selectivity for target molecules. Compared to traditional coal tar pitch, ethylene tar pitch is rich in easily graphitized spinnable components. When combined with anthracene oil, it further optimizes rheological properties and carbonization yield, significantly improving the mechanical strength and adsorption performance of the final product. Furthermore, the ethylene tar pitch and anthracene oil blend system contains more aromatic structures and fewer impurities than the coal tar pitch system, making it easier to form an ordered structure during carbonization, promoting the development of graphite crystals, constructing a conductive network with fewer defects and a denser structure, reducing recombination centers for photogenerated carriers, and facilitating the formation of uniformly sized, porous, and highly conductive spherical structures. This not only benefits light scattering and reactant mass transfer, but more importantly, it enables efficient electron separation and transport when used as a support, and its surface and band structure are more controllable when used as a catalyst. Therefore, it achieves superior charge separation efficiency, mass transport capability, and performance consistency in photocatalytic applications, making it a more ideal high-performance, designable platform. This approach not only optimizes the preparation efficiency and product quality of spherical activated carbon, but also provides a reliable material basis for promoting its large-scale application in high-end adsorption, catalysis, and energy storage. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 surface loading, which optimizes the raw material system, improves the processing performance and reactivity of asphalt, thereby enhancing the controllability and overall efficiency of the preparation process, and obtaining spherical activated carbon with high strength, high yield and high efficiency photocatalytic function.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 surface loading includes the following steps: 1) Using ethylene tar pitch with a softening point of 200-250℃ and / or coal tar pitch with a softening point of 200-250℃ as raw material pitch, a blending solvent is added to the raw material pitch to obtain blended pitch; 2) After crushing the blended asphalt, pass it through a 100-mesh sieve to obtain asphalt particles. Then, perform Soxhlet extraction on the blended asphalt with pyridine solution. Cool the extracted solution and collect the filtrate by filtration. 3) Mix polyvinyl alcohol 1788 type, anhydrous ethanol solution, and deionized water in a flask, heat and stir in a water bath until the polyvinyl alcohol is completely dissolved, cool to room temperature to obtain PVA solution; 4) Mix the filtrate obtained in step 2) and the PVA solution obtained in step 3), and then sonicate the resulting mixture. 5) Heat and stir the mixed solution at 80℃~95℃, then keep it at a constant temperature and stir for 30~60 minutes; 6) After stirring, the solution is cooled to room temperature and then filtered to obtain blended asphalt balls; 7) Place the obtained blended asphalt balls in a vacuum drying oven and dry them at 80℃~120℃ for more than 12 hours; 8) Non-melting treatment of the dried blended asphalt balls: Mix the obtained blended asphalt balls with 1 to 2 times the mass of KNO3, place them in a tube furnace, heat them to 290 to 320°C in an air atmosphere, and keep them at this temperature for 120 to 240 minutes. Let them cool naturally and then take them out. 9) Wash the sample obtained in step 8) with water to remove soluble KNO3 and obtain non-melting blended asphalt balls; 10) Place the sample obtained in step 9) in a tube furnace and heat it to 490–520°C under a nitrogen atmosphere, then hold it at this temperature for 120–240 min. After cooling, carbonized blended asphalt balls are obtained. 11) The sample obtained in step 10) is dissolved in deionized water with KOH at a mass ratio of 1:1 to 1.5:1. After stirring evenly, the mixture is transferred to a nickel boat and dried in a forced-air drying oven at 80 to 100°C. After the water has completely evaporated, the nickel boat is placed in a tube furnace and heated to 400 to 430°C under a nitrogen atmosphere and held for 60 to 120 minutes. Then the temperature is increased to 750°C and held at that temperature for 60 to 120 minutes. 12) After cooling, wash off the KOH with dilute hydrochloric acid, dry and collect at 80-100℃ to obtain blended pitch spherical activated carbon; 13) According to the proportion of TiO2 to TiO2 / blended pitch spherical activated carbon, nano-titanium dioxide is loaded onto the surface of blended pitch composite spherical activated carbon by impregnation method. After vacuum drying, it is placed in a vacuum tube furnace and heated from room temperature to 480-520℃ at a heating rate of 3-5℃ / min under nitrogen protection. It is then calcined for 100-140min. After natural cooling, TiO2 / blended pitch pitch-based spherical activated carbon is obtained.

[0007] The blending solvent accounts for 1 wt% to 60 wt% of the raw material asphalt.

[0008] The blending solvent is one or more of the following: cracked naphthalene fraction, anthracene oil, phenanthrene oil, and indene oil.

[0009] In step 1), the raw material asphalt and the blending solvent are stirred at 30-150℃ for 0.5-2 hours to obtain blended asphalt.

[0010] In step 3), the following steps are required: 3-5g of polyvinyl alcohol 1788; 25-35ml of anhydrous ethanol solution; and 150-250ml of deionized water.

[0011] The heating temperature mentioned in step 3) is 80-100℃.

[0012] The filtrate and PVA solution described in step 4) are mixed at a volume ratio of 1:(0.9 to 1.2); the mixed solution is ultrasonically vibrated for 15 to 30 minutes.

[0013] In step 11), the amount of deionized water is 40-60 mL.

[0014] The Soxhlet extraction described in step 2) is carried out at 120–130°C.

[0015] The specific surface area of ​​the obtained blended pitch spherical activated carbon is 2300–2500 m². 2 / g; Total pore volume 1.38–1.45 cm³ 3 / g; Iodine adsorption value is 2700~3000mg / g.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention, in the preparation of asphalt-based spherical activated carbon, adds a blending solvent to high-softening-point asphalt. Its core advantage lies in significantly improving the efficiency, controllability, and final product quality of the entire production process by optimizing the processing performance and reactivity of the raw materials. Specifically, the added blending solvent, acting as an excellent diluent and hydrogen donor, effectively reduces the viscosity of the raw material system, making it easier to form microspheres with perfect sphericity and uniform particle size. Simultaneously, the blending solvent significantly optimizes the critical infusible process, making it faster, gentler, and easier to control by initiating and promoting cross-linking reactions. This avoids sintering and excessive oxidation of the spheres, increases the yield of intermediate products, and lays a solid foundation for obtaining high-strength, high-yield, high-quality spherical activated carbon. The modified spherical activated carbon can achieve a specific surface area of ​​2300–2500 m². 2 ·g -1 The iodine adsorption value can reach 2700-3000 mg·g. -1 Its strength can reach over 99%, which is a significant improvement compared to traditional coal tar pitch-based spherical activated carbon.

[0017] This invention uses high-temperature ethylene tar pitch and / or high-temperature coal tar pitch as raw materials, with the addition of a blending solvent. High-temperature ethylene tar pitch and high-temperature coal tar pitch are ideal raw material choices for preparing high-performance pitch-based spherical activated carbon due to their excellent sphericity, high residual carbon, easily controllable pore structure, high purity, and high strength. The blending solvent is selected from one or more of cracked naphthalene fraction, anthracene oil, phenanthrene oil, and indene oil as a diluent and hydrogen donor. The released active hydrogen can control the free radical reaction pathway of pitch pyrolysis, achieving ordered carbonization, thereby directionally preparing spherical activated carbon with high strength, specific pore size, and high yield.

[0018] The pitch-based spherical activated carbon prepared by this invention has the characteristics of good sphericity, uniform particle size, high strength, large specific surface area, well-developed pore structure, and excellent adsorption performance, and is suitable for high-end adsorption and catalysis fields.

[0019] This invention uses pitch-based spherical activated carbon as a carrier to load nano-TiO2, a photocatalytic material, to form a composite bactericidal material. Through the synergistic effect of bacterial adsorption and enrichment and photocatalytic decomposition, it achieves highly efficient sterilization under light irradiation, with a sterilization rate of up to 99.9% within 120 minutes, outperforming traditional photocatalytic bactericidal materials. Attached Figure Description

[0020] Figure 1 This is a flowchart of the preparation process of the present invention.

[0021] Figure 2 This is a scanning electron microscope image of a blended pitch-based spherical activated carbon composite material.

[0022] Figure 3 Scanning electron microscope image of the surface-loaded TiO2 composite photocatalytic spherical activated carbon prepared according to the present invention.

[0023] Figure 4 The image shows the bactericidal performance evaluation of the composite photocatalytic spherical activated carbon with surface-loaded TiO2 prepared in this invention.

[0024] In the figures, (a) is a blank sample without treatment; (b) is a bacterial culture of wastewater simulating sunlight irradiation; (c) is a bacterial culture of wastewater simulating sunlight irradiation of TiO2 / blended pitch-based spherical activated carbon in Example 1; (d) is a bacterial culture of wastewater simulating sunlight irradiation of TiO2 / blended pitch-based spherical activated carbon in Example 2; and (e) is a bacterial culture of wastewater simulating sunlight irradiation of TiO2 / blended pitch-based spherical activated carbon in Example 3.

[0025] Figure 5 The impedance performance diagrams are shown for coal tar pitch-based spherical activated carbon and blended pitch pitch-based spherical activated carbon.

[0026] Figure 6 The image shows the XRD pattern of pitch-based composite activated carbon balls with TiO2 loaded on the surface. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0028] Example 1: like Figure 1 As shown, this embodiment is a blended pitch-based spherical activated carbon composite material, which is prepared by the following steps: (1) Mix ethylene tar pitch with anthracene oil at a mass ratio of 1:1 in a three-necked flask, mix at 150°C for 1 hour, pour out and cool to obtain blended pitch.

[0029] (2) Crush the blended asphalt and pass it through a 100-mesh sieve to obtain blended asphalt particles. Weigh 1g of the blended asphalt and place it in a funnel-shaped filter paper, then place the filter paper into a Soxhlet extractor. Add two boiling stones and a small amount of pyridine to a round-bottom flask and sonicate for 2 minutes to rinse the inner wall. After rinsing, discard the solution. Then, measure 100mL of pyridine and add it to the round-bottom flask. Connect the Soxhlet extractor to the condenser and fix the extraction device. After introducing cooling water, heat the round-bottom flask with an electric furnace and start the extraction. When the liquid in the Soxhlet extractor gradually becomes clear, it indicates that the soluble components have been fully dissolved, and stop the extraction. Cool the extract for later use.

[0030] (3) Weigh 3g of polyvinyl alcohol (PVA-1788 type) into a round-bottom flask and add a magnetic stir bar. Mix 28mL of anhydrous ethanol with 150mL of deionized water and pour the mixture into the flask. Place the flask on a water bath with a magnetic stirrer, install a condenser and circulate cooling water. Set the water bath temperature to 90℃ and turn on the magnetic stirrer until the polyvinyl alcohol is completely dissolved. Cool and set aside.

[0031] (4) Filter the extract from step (2), collect the filtrate and transfer it to a round-bottom flask. Add the surfactant solution prepared in step (3) and mix thoroughly by ultrasonication. Place the round-bottom flask in a water bath at 87°C and stir with a top stirrer at 400 rpm.

[0032] (5) When the water bath temperature reaches 87°C, continue stirring for 40 minutes, then stop heating and cool the liquid.

[0033] (6) Pour out the supernatant, collect the lower suspension, and filter it to obtain uniform asphalt balls.

[0034] (7) Place the obtained blended asphalt balls into a vacuum drying oven and dry at 120°C for 12 hours.

[0035] (8) Non-melting treatment of the dried blended asphalt balls: The obtained asphalt balls are thoroughly mixed with twice the mass of KNO3 and spread evenly on a glass plate. Then, they are placed in a tube furnace and slowly heated to 300°C at a heating rate of 0.5°C / min in an air atmosphere, and held at this temperature for 180 min.

[0036] (9) Wash the sample obtained in step (8) with water to remove soluble KNO3 and obtain non-melting blended asphalt balls; (10) Place the sample obtained in step (9) in a tube furnace and heat it to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere, and carbonize it at this temperature for 180 min. After cooling, carbonized asphalt balls are obtained.

[0037] (11) Weigh the sample obtained in step (10) and dissolve it in 10 mL of deionized water with 1.5 times its mass of KOH. After stirring evenly, transfer the mixture to a nickel boat and dry it in an 80°C forced-air drying oven. After the water has completely evaporated, place the nickel boat in a tube furnace and heat it to 400°C at a rate of 5°C / min under a nitrogen atmosphere, and hold it at that temperature for 120 min. Then, heat it to 750°C at a rate of 3°C / min and hold it at that temperature for 120 min.

[0038] (12) After cooling, wash off KOH with dilute hydrochloric acid, dry at 100℃ for 12h and collect to obtain blended pitch spherical activated carbon.

[0039] Example 2: like Figure 1 As shown, this embodiment is a blended pitch-based spherical activated carbon composite material, which is prepared by the following steps: (1) The refined coal tar pitch with a softening point of 200℃ and anthracene oil were mixed in a mass ratio of 1:1 and added to a three-necked flask. After mixing at 150℃ for 1 hour, the mixture was poured out and cooled to obtain the blended pitch.

[0040] (2) Crush the blended asphalt and pass it through a 100-mesh sieve to obtain blended asphalt particles. Weigh 1g of the blended asphalt and place it in a funnel-shaped filter paper, then place the filter paper into a Soxhlet extractor. Add two boiling stones and a small amount of pyridine to a round-bottom flask and sonicate for 2 minutes to rinse the inner wall. After rinsing, discard the solution. Then, measure 100mL of pyridine and add it to the round-bottom flask. Connect the Soxhlet extractor to the condenser and fix the extraction device. After introducing cooling water, heat the round-bottom flask with an electric furnace and start the extraction. When the liquid in the Soxhlet extractor gradually becomes clear, it indicates that the soluble components have been fully dissolved, and stop the extraction. Cool the extract for later use.

[0041] (3) Weigh 3g of polyvinyl alcohol (PVA-1788 type) into a round-bottom flask and add a magnetic stir bar. Mix 28mL of anhydrous ethanol with 150mL of deionized water and pour the mixture into the flask. Place the flask on a water bath with a magnetic stirrer, install a condenser and circulate cooling water. Set the water bath temperature to 90℃ and turn on the magnetic stirrer until the polyvinyl alcohol is completely dissolved. Cool and set aside.

[0042] (4) Filter the extract from step (2), collect the filtrate and transfer it to a round-bottom flask. Add the surfactant solution prepared in step (3) and mix thoroughly by ultrasonication. Place the round-bottom flask in a water bath at 87°C and stir with a top stirrer at 400 rpm.

[0043] (5) When the water bath temperature reaches 87°C, continue stirring for 40 minutes, then stop heating and cool the liquid.

[0044] (6) Pour out the supernatant, collect the lower suspension, and filter it to obtain uniform asphalt balls.

[0045] (7) Place the obtained blended asphalt balls into a vacuum drying oven and dry at 120°C for 12 hours.

[0046] (8) Non-melting treatment of the dried blended asphalt balls: The obtained asphalt balls are thoroughly mixed with twice the mass of KNO3 and spread evenly on a glass plate. Then, they are placed in a tube furnace and slowly heated to 300°C at a heating rate of 0.5°C / min in an air atmosphere, and held at this temperature for 180 min.

[0047] (9) Wash the sample obtained in step (8) with water to remove soluble KNO3 and obtain non-melting blended asphalt balls; (10) Place the sample obtained in step (9) in a tube furnace and heat it to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere, and carbonize it at this temperature for 180 min. After cooling, carbonized asphalt balls are obtained.

[0048] (11) Weigh the sample obtained in step (10) and dissolve it in 10 mL of deionized water with 1.5 times its mass of KOH. After stirring evenly, transfer the mixture to a nickel boat and dry it in an 80°C forced-air drying oven. After the water has completely evaporated, place the nickel boat in a tube furnace and heat it to 400°C at a rate of 5°C / min under a nitrogen atmosphere, and hold it at that temperature for 120 min. Then, heat it to 750°C at a rate of 3°C / min and hold it at that temperature for 120 min.

[0049] (12) After cooling, wash off KOH with dilute hydrochloric acid, dry at 100℃ for 12h and collect to obtain blended pitch spherical activated carbon.

[0050] Example 3: like Figure 1 As shown, this embodiment is a blended pitch-based spherical activated carbon composite material, which is prepared by the following steps: (1) The refined coal tar pitch with a softening point of 200℃, the ethylene tar pitch with a softening point of 200℃, the anthracene oil and the phenanthrene oil were mixed in a weight ratio of 1:1:1:1 and added to a three-necked flask. After mixing at 150℃ for 1 hour, the mixture was poured out and cooled to obtain the blended pitch.

[0051] (2) Crush the blended asphalt and pass it through a 100-mesh sieve to obtain blended asphalt particles. Weigh 1g of the blended asphalt and place it in a funnel-shaped filter paper, then place the filter paper into a Soxhlet extractor. Add two boiling stones and a small amount of pyridine to a round-bottom flask and sonicate for 2 minutes to rinse the inner wall. After rinsing, discard the solution. Then, measure 100mL of pyridine and add it to the round-bottom flask. Connect the Soxhlet extractor to the condenser and fix the extraction device. After introducing cooling water, heat the round-bottom flask with an electric furnace and start the extraction. When the liquid in the Soxhlet extractor gradually becomes clear, it indicates that the soluble components have been fully dissolved, and stop the extraction. Cool the extract for later use.

[0052] (3) Weigh 3g of polyvinyl alcohol (PVA-1788 type) into a round-bottom flask and add a magnetic stir bar. Mix 28mL of anhydrous ethanol with 150mL of deionized water and pour the mixture into the flask. Place the flask on a water bath with a magnetic stirrer, install a condenser and circulate cooling water. Set the water bath temperature to 90℃ and turn on the magnetic stirrer until the polyvinyl alcohol is completely dissolved. Cool and set aside.

[0053] (4) Filter the extract from step (2), collect the filtrate and transfer it to a round-bottom flask. Add the surfactant solution prepared in step (3) and mix thoroughly by ultrasonication. Place the round-bottom flask in a water bath at 87°C and stir with a top stirrer at 400 rpm.

[0054] (5) When the water bath temperature reaches 87°C, continue stirring for 40 minutes, then stop heating and cool the liquid.

[0055] (6) Pour out the supernatant, collect the lower suspension, and filter it to obtain uniform asphalt balls.

[0056] (7) Place the obtained blended asphalt balls into a vacuum drying oven and dry at 120°C for 12 hours.

[0057] (8) Non-melting treatment of the dried blended asphalt balls: The obtained asphalt balls are thoroughly mixed with twice the mass of KNO3 and spread evenly on a glass plate. Then, they are placed in a tube furnace and slowly heated to 300°C at a heating rate of 0.5°C / min in an air atmosphere, and held at this temperature for 180 min.

[0058] (9) Wash the sample obtained in step (8) with water to remove soluble KNO3 and obtain non-melting blended asphalt balls; (10) Place the sample obtained in step (9) in a tube furnace and heat it to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere, and carbonize it at this temperature for 180 min. After cooling, carbonized asphalt balls are obtained.

[0059] (11) Weigh the sample obtained in step (10) and dissolve it in 10 mL of deionized water with 1.5 times its mass of KOH. After stirring evenly, transfer the mixture to a nickel boat and dry it in an 80°C forced-air drying oven. After the water has completely evaporated, place the nickel boat in a tube furnace and heat it to 400°C at a rate of 5°C / min under a nitrogen atmosphere, and hold it at that temperature for 120 min. Then, heat it to 750°C at a rate of 3°C / min and hold it at that temperature for 120 min.

[0060] (12) After cooling, wash off KOH with dilute hydrochloric acid, dry at 100℃ for 12h and collect to obtain blended pitch spherical activated carbon.

[0061] Comparative Example 1: This comparative example illustrates a method for preparing an asphalt-based spherical activated carbon composite material, which is obtained through the following steps: (1) Pulverize the ethylene tar pitch with a softening point of 200℃ and then pass it through a 100-mesh sieve to obtain ethylene tar pitch particles.

[0062] (2) Weigh 1g of ethylene tar pitch and place it in a funnel-shaped filter paper, then place the filter paper into a Soxhlet extractor. Add two boiling chips and a small amount of pyridine to a round-bottom flask, and sonicate for 2 minutes to rinse the inner wall. Discard the solution after rinsing. Then, measure 100mL of pyridine and add it to the round-bottom flask, connect the Soxhlet extractor to the condenser, and fix the extraction device. After introducing cooling water, heat the round-bottom flask with an electric furnace and start the extraction. When the liquid in the Soxhlet extractor gradually becomes clear, it indicates that the soluble components have been fully dissolved, and stop the extraction. Cool the extract for later use.

[0063] (3) Weigh 3g of polyvinyl alcohol (PVA-1788 type) into a round-bottom flask and add a magnetic stir bar. Mix 28mL of anhydrous ethanol with 150mL of deionized water and pour the mixture into the flask. Place the flask on a water bath with a magnetic stirrer, install a condenser and circulate cooling water. Set the water bath temperature to 90℃ and turn on the magnetic stirrer until the polyvinyl alcohol is completely dissolved. Cool and set aside.

[0064] (4) Filter the extract from step (2), collect the filtrate and transfer it to a round-bottom flask. Add the surfactant solution prepared in step (3) and mix thoroughly by ultrasonication. Place the round-bottom flask in a water bath at 87°C and stir with a top stirrer at 400 rpm.

[0065] (5) When the water bath temperature reaches 87°C, continue stirring for 40 minutes, then stop heating and cool the liquid.

[0066] (6) Pour out the supernatant, collect the lower suspension, and filter it to obtain uniform asphalt balls.

[0067] (7) Place the obtained asphalt balls in a vacuum drying oven and dry at 120°C for 12 hours.

[0068] (8) Non-melting treatment of dried asphalt balls: The obtained asphalt balls are thoroughly mixed with twice the mass of KNO3 and spread evenly on a glass plate. Then, they are placed in a tube furnace and slowly heated to 300°C at a heating rate of 0.5°C / min in an air atmosphere, and held at this temperature for 180 min.

[0069] (9) Wash the sample obtained in step (8) with water to remove soluble KNO3 and obtain non-melting asphalt balls; (10) Place the sample obtained in step (9) in a tube furnace and heat it to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere, and carbonize it at this temperature for 180 min. After cooling, carbonized asphalt balls are obtained.

[0070] (11) Weigh the sample obtained in step (10) and dissolve it in 10 mL of deionized water with 1.5 times its mass of KOH. After stirring evenly, transfer the mixture to a nickel boat and dry it in an 80°C forced-air drying oven. After the water has completely evaporated, place the nickel boat in a tube furnace and heat it to 400°C at a rate of 5°C / min under a nitrogen atmosphere, and hold it at that temperature for 120 min. Then, heat it to 750°C at a rate of 3°C / min and hold it at that temperature for 120 min.

[0071] (12) After cooling, wash off KOH with dilute hydrochloric acid, dry at 100℃ for 12h and collect to obtain pitch-based spherical activated carbon.

[0072] Comparative Example 2: This comparative example illustrates a method for preparing an asphalt-based spherical activated carbon composite material, which is obtained through the following steps: (1) Pulverize refined coal tar pitch with a softening point of 200℃ and then pass it through a 100-mesh sieve to obtain ethylene tar pitch particles.

[0073] (2) Weigh 1g of refined coal tar pitch and place it in a funnel-shaped filter paper, then place the filter paper into a Soxhlet extractor. Add two boiling stones and a small amount of pyridine to a round-bottom flask, and sonicate for 2 minutes to rinse the inner wall. Discard the solution after rinsing. Then, measure 100mL of pyridine and add it to the round-bottom flask, connect the Soxhlet extractor to the condenser, and fix the extraction device. After introducing cooling water, heat the round-bottom flask with an electric furnace and start the extraction. When the liquid in the Soxhlet extractor gradually becomes clear, it indicates that the soluble components have been fully dissolved, and the extraction is stopped. Cool the extract for later use.

[0074] (3) Weigh 3g of polyvinyl alcohol (PVA-1788 type) into a round-bottom flask and add a magnetic stir bar. Mix 28mL of anhydrous ethanol with 150mL of deionized water and pour the mixture into the flask. Place the flask on a water bath with a magnetic stirrer, install a condenser and circulate cooling water. Set the water bath temperature to 90℃ and turn on the magnetic stirrer until the polyvinyl alcohol is completely dissolved. Cool and set aside.

[0075] (4) Filter the extract from step (2), collect the filtrate and transfer it to a round-bottom flask. Add the surfactant solution prepared in step (3) and mix thoroughly by ultrasonication. Place the round-bottom flask in a water bath at 87°C and stir with a top stirrer at 400 rpm.

[0076] (5) When the water bath temperature reaches 87°C, continue stirring for 40 minutes, then stop heating and cool the liquid.

[0077] (6) Pour out the supernatant, collect the lower suspension, and filter it to obtain uniform asphalt balls.

[0078] (7) Place the obtained asphalt balls in a vacuum drying oven and dry at 120°C for 12 hours.

[0079] (8) Non-melting treatment of dried asphalt balls: The obtained asphalt balls are thoroughly mixed with twice the mass of KNO3 and spread evenly on a glass plate. Then, they are placed in a tube furnace and slowly heated to 300°C at a heating rate of 0.5°C / min in an air atmosphere, and held at this temperature for 180 min.

[0080] (9) Wash the sample obtained in step (8) with water to remove soluble KNO3 and obtain non-melting asphalt balls; (10) Place the sample obtained in step (9) in a tube furnace and heat it to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere, and carbonize it at this temperature for 180 min. After cooling, carbonized asphalt balls are obtained.

[0081] (11) Weigh the sample obtained in step (10) and dissolve it in 10 mL of deionized water with 1.5 times its mass of KOH. After stirring evenly, transfer the mixture to a nickel boat and dry it in an 80°C forced-air drying oven. After the water has completely evaporated, place the nickel boat in a tube furnace and heat it to 400°C at a rate of 5°C / min under a nitrogen atmosphere, and hold it at that temperature for 120 min. Then, heat it to 750°C at a rate of 3°C / min and hold it at that temperature for 120 min.

[0082] (12) After cooling, wash off KOH with dilute hydrochloric acid, dry at 100℃ for 12h and collect to obtain pitch-based spherical activated carbon.

[0083] Comparative Example 3: This comparative example illustrates a method for preparing an asphalt-based spherical activated carbon composite material, which is obtained through the following steps: (1) Mix and crush ethylene tar pitch with softening point 200℃ and refined coal pitch with softening point 200℃ in a 1:1 ratio, and then pass through a 100-mesh sieve to obtain mixed pitch particles.

[0084] (2) Weigh 1g of mixed asphalt and place it in a funnel-shaped filter paper, then place the filter paper into a Soxhlet extractor. Add two boiling stones and a small amount of pyridine to a round-bottom flask, and sonicate for 2 minutes to rinse the inner wall. Discard the solution after rinsing. Then, measure 100mL of pyridine and add it to the round-bottom flask, connect the Soxhlet extractor to the condenser, and fix the extraction device. After introducing cooling water, heat the round-bottom flask with an electric furnace and start the extraction. When the liquid in the Soxhlet extractor gradually becomes clear, it indicates that the soluble components have been fully dissolved, and stop the extraction. Cool the extract for later use.

[0085] (3) Weigh 3g of polyvinyl alcohol (PVA-1788 type) into a round-bottom flask and add a magnetic stir bar. Mix 28mL of anhydrous ethanol with 150mL of deionized water and pour the mixture into the flask. Place the flask on a water bath with a magnetic stirrer, install a condenser and circulate cooling water. Set the water bath temperature to 90℃ and turn on the magnetic stirrer until the polyvinyl alcohol is completely dissolved. Cool and set aside.

[0086] (4) Filter the extract from step (2), collect the filtrate and transfer it to a round-bottom flask. Add the surfactant solution prepared in step (3) and mix thoroughly by ultrasonication. Place the round-bottom flask in a water bath at 87°C and stir with a top stirrer at 400 rpm.

[0087] (5) When the water bath temperature reaches 87°C, continue stirring for 40 minutes, then stop heating and cool the liquid.

[0088] (6) Pour out the supernatant, collect the lower suspension, and filter it to obtain uniform asphalt balls.

[0089] (7) Place the obtained asphalt balls in a vacuum drying oven and dry at 120°C for 12 hours.

[0090] (8) Non-melting treatment of dried asphalt balls: The obtained asphalt balls are thoroughly mixed with twice the mass of KNO3 and spread evenly on a glass plate. Then, they are placed in a tube furnace and slowly heated to 300°C at a heating rate of 0.5°C / min in an air atmosphere, and held at this temperature for 180 min.

[0091] (9) Wash the sample obtained in step (8) with water to remove soluble KNO3 and obtain non-melting asphalt balls; (10) Place the sample obtained in step (9) in a tube furnace and heat it to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere, and carbonize it at this temperature for 180 min. After cooling, carbonized asphalt balls are obtained.

[0092] (11) Weigh the sample obtained in step (10) and dissolve it in 10 mL of deionized water with 1.5 times its mass of KOH. After stirring evenly, transfer the mixture to a nickel boat and dry it in an 80°C forced-air drying oven. After the water has completely evaporated, place the nickel boat in a tube furnace and heat it to 400°C at a rate of 5°C / min under a nitrogen atmosphere, and hold it at that temperature for 120 min. Then, heat it to 750°C at a rate of 3°C / min and hold it at that temperature for 120 min.

[0093] (12) After cooling, wash off KOH with dilute hydrochloric acid, dry at 100℃ for 12h and collect to obtain pitch-based spherical activated carbon.

[0094] The performance of the high-strength, high-efficiency pitch-based spherical activated carbon in Examples 1-3 and Comparative Examples 1-3 was tested, and the test results are shown below: Referring to the data in the table above, and based on the comparison between Examples 1-3 and Comparative Examples 1-3, it can be seen that the modification treatment with the addition of one or more of the following as diluents and hydrogen donors—cracking naphthalene fraction, anthracene oil, phenanthrene oil, and indene oil—can effectively improve its specific surface area and adsorption performance.

[0095] The asphalt-based spherical activated carbons of Examples 1-3 and Comparative Examples 1-3 were analyzed by scanning electron microscopy. The results are as follows: Figure 2 As shown: Compared with Comparative Examples 1-3, the spherical activated carbon with added anthracene oil or phenanthrene oil in Examples 1-3 showed a significantly higher spherical formation rate and smoother surface than the spherical activated carbon without added anthracene oil or pyrolyzed naphthalene. This is because the addition of anthracene oil and phenanthrene oil effectively reduced the viscosity of the raw material system, making it easier to form microspheres with perfect sphericity and uniform particle size. At the same time, it significantly optimized the key non-melting process, making the process faster, gentler, and easier to control by initiating and promoting the cross-linking reaction, thereby avoiding sintering and excessive oxidation of the spheres and improving the yield of intermediate products.

[0096] Using the blended pitch spherical activated carbon from Examples 1-3 as raw materials, and with TiO2 accounting for 10 wt% of the total weight of TiO2 / blended pitch spherical activated carbon, nano-titanium dioxide was loaded onto the surface of the blended pitch composite spherical activated carbon using an impregnation method. After vacuum drying, it was placed in a vacuum tube furnace and calcined at a rate of 3 °C / min from room temperature to 500 °C under gas protection, and held at that temperature for 120 min. After natural cooling, TiO2 / blended pitch pitch-based spherical activated carbon was prepared. Its scanning electron microscope image is shown below. Figure 3 To evaluate its bactericidal performance, such as Figure 4 .

[0097] The impedance performance of the blended pitch spherical activated carbon from Example 1 and the coal pitch-based spherical activated carbon from Comparative Example 2 was evaluated. Figure 5 Compared to coal tar pitch, the ethylene tar pitch and anthracene oil blend system contains more aromatic structures and fewer impurities. During the carbonization process, it is easier to form an ordered structure, promote the development of graphite microcrystals, and construct a conductive network with fewer defects and a denser structure. Therefore, the spherical activated carbon prepared by the blend pitch has better conductivity.

[0098] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0099] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 supported on its surface, characterized in that, Includes the following steps: 1) Using ethylene tar pitch with a softening point of 200-250℃ and / or coal tar pitch with a softening point of 200-250℃ as raw material pitch, a blending solvent is added to the raw material pitch to obtain blended pitch; 2) After crushing the blended asphalt, pass it through a 100-mesh sieve to obtain asphalt particles. Then, perform Soxhlet extraction on the blended asphalt with pyridine solution. Cool the extracted solution and collect the filtrate by filtration. 3) Mix polyvinyl alcohol 1788 type, anhydrous ethanol solution, and deionized water in a flask, heat and stir in a water bath until the polyvinyl alcohol is completely dissolved, cool to room temperature to obtain PVA solution; 4) Mix the filtrate obtained in step 2) and the PVA solution obtained in step 3), and then sonicate the resulting mixture. 5) Heat and stir the mixed solution at 80℃~95℃, then keep it at a constant temperature and stir for 30~60 minutes; 6) After stirring, the solution is cooled to room temperature and then filtered to obtain blended asphalt balls; 7) Place the obtained blended asphalt balls in a vacuum drying oven and dry them at 80℃~120℃ for more than 12 hours; 8) Non-melting treatment of the dried blended asphalt balls: Mix the obtained blended asphalt balls with 1 to 2 times the mass of KNO3, place them in a tube furnace, heat them to 290 to 320°C in an air atmosphere, and keep them at this temperature for 120 to 240 minutes. Let them cool naturally and then take them out. 9) Wash the sample obtained in step 8) with water to remove soluble KNO3 and obtain non-melting blended asphalt balls; 10) Place the sample obtained in step 9) in a tube furnace, heat it to 490-520°C under a nitrogen atmosphere, and hold it at this temperature for 120-240 min; after cooling, carbonized blended asphalt balls are obtained. 11) The sample obtained in step 10) is dissolved in deionized water with KOH at a mass ratio of 1:1 to 1.5:

1. After stirring evenly, the mixture is transferred to a nickel boat and dried in a forced-air drying oven at 80 to 100°C. After the water has completely evaporated, the nickel boat is placed in a tube furnace and heated to 400 to 430°C under a nitrogen atmosphere and held for 60 to 120 minutes. Then the temperature is increased to 750°C and held at that temperature for 60 to 120 minutes. 12) After cooling, wash off the KOH with dilute hydrochloric acid, dry and collect at 80-100℃ to obtain blended pitch spherical activated carbon; 13) According to the proportion of TiO2 to TiO2 / blended pitch spherical activated carbon, nano-titanium dioxide is loaded onto the surface of blended pitch composite spherical activated carbon by impregnation method. After vacuum drying, it is placed in a vacuum tube furnace and heated from room temperature to 480-520℃ at a heating rate of 3-5℃ / min under nitrogen protection. It is then calcined for 100-140min. After natural cooling, TiO2 / blended pitch pitch-based spherical activated carbon is obtained.

2. The method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 surface loading according to claim 1, characterized in that, The blending solvent accounts for 1 wt% to 60 wt% of the raw material asphalt.

3. The method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 surface loading according to claim 1, characterized in that, The blending solvent is one or more of the following: cracked naphthalene fraction, anthracene oil, phenanthrene oil, and indene oil.

4. The method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 surface loading according to claim 1, characterized in that, In step 1), the raw material asphalt and the blending solvent are stirred at 30-150℃ for 0.5-2 hours to obtain blended asphalt.

5. The method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 surface loading according to claim 1, characterized in that, In step 3), the following steps are required: 3-5g of polyvinyl alcohol 1788; 25-35ml of anhydrous ethanol solution; and 150-250ml of deionized water.

6. The method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 surface loading according to claim 1, characterized in that, The heating temperature mentioned in step 3) is 80-100℃.

7. The method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 surface loading according to claim 1, characterized in that, The filtrate and PVA solution described in step 4) are mixed at a volume ratio of 1:(0.9 to 1.2); the mixed solution is ultrasonically vibrated for 15 to 30 minutes.

8. The method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 surface loading according to claim 1, characterized in that, In step 11), the amount of deionized water is 40-60 mL.

9. The method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 surface loading according to claim 1, characterized in that, The Soxhlet extraction described in step 2) is carried out at 120–130°C.

10. The method for preparing ethylene tar-based composite photocatalytic spherical activated carbon with TiO2 surface loading according to claim 1, characterized in that, The specific surface area of ​​the obtained blended pitch spherical activated carbon is 2300–2500 m². 2 / g; Total pore volume 1.38–1.45 cm³ 3 / g; Iodine adsorption value is 2700~3000mg / g.

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