Post-treatment method and application of activated carbon carrier

Abstract

The invention discloses a post-treatment method of an activated carbon carrier. The post-treatment method comprises the following steps: S1, pretreatment of activated carbon: washing and drying the activated carbon, and roasting to obtain a first activated carbon carrier; s2, post-treatment of activated carbon: mixing a fluoride aqueous solution with the first activated carbon carrier, stirring, washing, drying and roasting to obtain a second activated carbon carrier. According to the post-treatment method, the ash content can be effectively reduced, and the specific surface area and pore connectivity of the activated carbon are improved.

Description

Technical Field

[0001] This invention relates to the field of catalysts, specifically to a post-treatment method and application of activated carbon supports. Background Technology

[0002] Activated carbon is a black carbonaceous porous material with a well-developed pore structure and a large specific surface area. It possesses advantages such as excellent adsorption performance, good chemical stability, acid and alkali resistance, and ease of preparation, and is widely used in adsorption, chemical, and biomedical fields. However, when activated carbon is used as a catalyst support, three main problems remain: ① It is predominantly microporous with a wide micropore distribution and small pore volume, making mass transfer and diffusion difficult; ② Its surface properties are complex, with few metal bonding sites, making them difficult to control and study. Therefore, activated carbon needs to be activated to optimize the pore structure, increase porosity, and improve chemical properties and defect levels, thereby enhancing its catalytic performance as a catalyst support; ③ Activated carbon has a complex composition, mainly composed of carbon and small amounts of ash, such as silicon, calcium, sulfur, and carbonates, which are difficult to remove simultaneously during processing.

[0003] Activated carbon activation commonly employs physical and chemical methods. Compared to physical activation, chemical activation requires lower activation temperatures, shorter activation times, and lower energy consumption, while also producing higher yields of activated carbon and allowing for more precise control of the pore structure and surface properties. By impregnating activated carbon with acidic or alkaline chemical reagents, acid- and alkali-soluble substances on its surface are removed, altering the number of oxygen- or nitrogen-containing functional groups and surface chemical properties to improve adsorption performance (International Journal of Environmental Science and Technology, 2021, 19: 4987-4996).

[0004] Most research on the activation of activated carbon with acidic reagents focuses on the use of HNO3 and H2SO4. According to relevant literature (Applied Surface Science, 2019, 471:633-644) and patent (CN105268738A), acid modification introduces O and N functional groups into the activated carbon surface by oxidizing the carbon on the micropore surface. This results in a wider micropore size distribution, increased specific surface area and micropore volume, significantly improving the adsorption performance of activated carbon for reactants. However, during acid treatment, some ash that is insoluble in acid is still retained (China Petroleum and Chemical Standards and Quality, 2020, 19:161-163). In addition, it changes the inherent chemical properties of the carbon surface and introduces strong acid sites, which become carbon deposition centers for catalytic reactions, thus affecting the stability of the reaction (Nature Catalysis, 2022, 5:854-866).

[0005] Most research on the activation of activated carbon with alkaline reagents focuses on the use of NaOH, KOH, etc. According to relevant literature (Environmental Chemistry Letters, 2020, 18:393-415) and patent (CN108097243B), after activation by impregnation with alkaline solution, soluble oxides in the pores of activated carbon are dissolved, reducing the ash content of activated carbon, increasing porosity, and significantly enhancing its adsorption performance. Alkali activation of activated carbon can not only increase its porosity and specific surface area, but also introduce some basic nitrogen and oxygen groups on the surface of activated carbon. However, it will still retain some ash that is insoluble in alkali (China Petroleum and Chemical Standards and Quality, 2020, 19:161-163), which cannot be removed at the same time. In addition, it will reduce the inherent acidic sites, reduce the interaction between the activated carbon and the metal active phase, and reduce the initial activity of the reaction (Catalysis Today, 2022, 405:168-181).

[0006] Furthermore, a patent (CN113353953A) reports that fluorine treatment can non-selectively dissolve unstable structural units. Therefore, for the parent carbon support, without changing the surface chemical properties and introducing additional strong acidic sites, direct fluorine chemical modification can indiscriminately dissolve unstable ash components, effectively reduce the ash content of activated carbon, improve the pore structure of activated carbon, introduce defect sites, expose more acidic sites, and improve the conversion rate and stability of the reaction. Summary of the Invention

[0007] The inventors of this invention aimed to simultaneously obtain the advantages of both acid- and alkaline-activated carbon. They creatively used fluorination reagents to treat activated carbon, which can indiscriminately dissolve ash that is insoluble in acids and alkalis, effectively improve porosity, expose more weak acid sites, and further destroy part of the graphitized structure, introducing defect sites to the maximum extent, resulting in higher catalytic activity compared to the parent carbon.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention provides a post-treatment method for activated carbon carriers, the post-treatment method comprising the following steps:

[0010] S1: Pretreatment of activated carbon: The activated carbon is washed with water, dried and then calcined to obtain the first activated carbon carrier;

[0011] S2: Post-treatment of activated carbon: After mixing and stirring the fluoride aqueous solution with the first activated carbon carrier, the second activated carbon carrier is obtained by washing, drying and calcining.

[0012] Furthermore, in step S1, deionized water is preferred for washing, and the washing method can be vacuum filtration, washing until there are no floating objects.

[0013] Further, in step S1, the drying temperature is 50–100℃, and the drying time is 0.5–12 h; the calcination temperature is 200–500℃, the heating rate is 2–10℃ / min, and the calcination time is 0.5–4 h. Preferably, the drying temperature is 80–100℃, the drying time is 2–12 h, the calcination temperature is 350–400℃, the heating rate is 5–10℃ / min, and the calcination time is 2–4 h.

[0014] Further, the concentration of the fluoride aqueous solution is 0.1–50.0 wt. / %. Preferably, the concentration of the fluoride aqueous solution is 0.1–40.0 wt. / %.

[0015] Furthermore, the fluoride is selected from at least one of hydrogen fluoride, fluorosilicic acid, potassium fluoride, ammonium fluoride, sodium fluoride, zinc fluoride, and zirconium fluoride.

[0016] Further, in step S2, the temperature during mixing and stirring of the fluoride aqueous solution and the first activated carbon carrier is 50–120°C, and the stirring time is 0.5–5 h. Preferably, the temperature during mixing and stirring is 70–100°C, and the stirring time is 0.5–2 h.

[0017] Further, the volume ratio of the first activated carbon carrier to the fluoride aqueous solution is 1:10 to 1:40. Preferably, the volume ratio of the first activated carbon carrier to the fluoride aqueous solution is 1:10 to 1:30.

[0018] Further, in step S2, the drying temperature is 50–100℃, and the drying time is 0.5–12 h; the calcination temperature is 200–500℃, the heating rate is 2–10℃ / min, and the calcination time is 0.5–3 h. Preferably, the drying temperature is 80–100℃, and the drying time is 2–12 h; the calcination temperature is 300–400℃, the heating rate is 5–10℃ / min, and the calcination time is 2–3 h.

[0019] The roasting described in this invention can be carried out in a roasting apparatus, preferably in a muffle furnace.

[0020] The present invention also provides an application of an activated carbon support, wherein the second activated carbon support serves as a catalyst support for loading catalyst active components.

[0021] The present invention also provides an application of an activated carbon support, wherein the second activated carbon support serves as a catalyst support for loading the active components of a catalyst for a hydrodehalogenation reaction.

[0022] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0023] (1) The post-treatment method of the present invention has no selectivity for the dissolution of ash (such as Al, Ca, S, Si, etc.), effectively reducing the ash content and improving the specific surface area and pore connectivity of activated carbon.

[0024] (2) The treated activated carbon has abundant weak acid sites;

[0025] (3) The post-processing method of the present invention can destroy the graphitized structure of the activated carbon support, which has abundant defect sites;

[0026] (4) The support treated by the post-treatment method of the present invention has excellent catalytic activity and good stability in the hydrodehalogenation reaction;

[0027] (5) The post-processing method of the present invention is simple and easy to apply on a large scale. Attached Figure Description

[0028] Figure 1 The XRD patterns of activated carbon A2 as described in this invention and activated carbon prepared in Example 2 and Comparative Examples 1-4. Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments, but the invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternatives, improvements, and equivalents that may be included within the scope of the claims.

[0030] The activated carbon carrier is named ACX-rSTt, where A is the concentration of the fluoride solution, X is the reagent abbreviation, S is the solid-liquid ratio, r is the treatment rotation speed, T is the treatment temperature, and t is the treatment time.

[0031] Example 1

[0032] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon A1.

[0033] Prepare 150g of a 0.1wt. / % hydrogen fluoride solution and stir thoroughly until homogeneous.

[0034] After heating the hydrogen fluoride solution to 70°C in an oil bath, 5g of activated carbon Al was added at a solid-liquid ratio of 1:10. The treatment time was 0.5h, and the rotation speed was 400r·pm. After thorough stirring and reaction, the mixture was washed until neutral and dried at 100°C for 10h. Then, it was calcined in a muffle furnace at a heating rate of 5°C / min to 300°C for 2h. The calcined activated carbon was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 0.1%CFH-400-10-70-0.5.

[0035] Example 2

[0036] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon A2.

[0037] Prepare 150g of a 40wt.% hydrogen fluoride solution and stir thoroughly until homogeneous.

[0038] After heating the hydrogen fluoride solution to 70°C in an oil bath, 5g of activated carbon A2 was added at a solid-liquid ratio of 1:30. The treatment time was 0.5h, and the rotation speed was 600r·pm. After thorough stirring and reaction, the mixture was washed until neutral and dried at 100°C for 10h. Then, it was calcined in a muffle furnace at a heating rate of 5°C / min to 300°C for 2h. The calcined activated carbon was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 40%CFH-600-30-70-0.5.

[0039] Example 3

[0040] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon A3.

[0041] Prepare 150g of a 40wt.% potassium fluoride solution and stir thoroughly until the potassium fluoride solid is completely dissolved.

[0042] After heating the potassium fluoride solution to 70°C in an oil bath, 5g of activated carbon A3 was added at a solid-liquid ratio of 1:30. The treatment time was 0.5h, and the rotation speed was 600r·pm. After thorough stirring and reaction, the mixture was washed until neutral and dried at 100°C for 10h. Then, it was calcined in a muffle furnace at a heating rate of 5°C / min to 300°C for 2h. The calcined activated carbon was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 40%CFK-600-30-70-0.5.

[0043] Example 4

[0044] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon A4.

[0045] Prepare 150g of a 40wt.% potassium fluoride solution and stir thoroughly until the potassium fluoride solid is completely dissolved.

[0046] After heating the potassium fluoride solution to 70°C in an oil bath, 5g of activated carbon A4 was added at a solid-liquid ratio of 1:30. The treatment time was 1.0h, and the rotation speed was 600r·pm. After thorough stirring and reaction, the mixture was washed until neutral and dried at 100°C for 10h. Then, it was calcined in a muffle furnace at a heating rate of 5°C / min to 300°C for 2h. The calcined activated carbon was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 40%CFK-600-30-70-1.0.

[0047] Example 5

[0048] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon A5.

[0049] Prepare 150g of a 40wt.% potassium fluoride solution and stir thoroughly until the potassium fluoride solid is completely dissolved.

[0050] After heating the potassium fluoride solution to 70°C in an oil bath, 5g of activated carbon A5 was added at a solid-liquid ratio of 1:30. The treatment time was 2.0h, and the rotation speed was 600r·pm. After thorough stirring and reaction, the mixture was washed until neutral and dried at 100°C for 10h. Then, it was calcined in a muffle furnace at a heating rate of 5°C / min to 300°C for 2h. The calcined activated carbon was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 40%CFK-600-30-70-2.0.

[0051] Example 6

[0052] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon A6.

[0053] Prepare 150g of a 40wt.% ammonium fluoride solution and stir thoroughly until the solid ammonium fluoride is completely dissolved.

[0054] After heating the ammonium fluoride solution to 70°C in an oil bath, 5g of activated carbon A6 was added at a solid-liquid ratio of 1:30. The treatment time was 0.5h, and the rotation speed was 600r·pm. After thorough stirring and reaction, the mixture was washed until neutral and dried at 100°C for 10h. Then, it was calcined in a muffle furnace at a heating rate of 5°C / min to 300°C for 2h. The calcined activated carbon was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 40%CFA-600-30-70-0.5.

[0055] Example 7

[0056] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon A7.

[0057] Prepare 150g of a 40wt.% ammonium fluoride solution and stir thoroughly until the solid ammonium fluoride is completely dissolved.

[0058] After heating the ammonium fluoride solution to 100℃ in an oil bath, 5g of activated carbon A7 was added at a solid-liquid ratio of 1:30. The treatment time was 0.5h, the rotation speed was 600r·pm, and the reaction was stirred thoroughly. After washing until neutral, the activated carbon carrier was dried at 100℃ for 10h, then heated to 300℃ in a muffle furnace at a heating rate of 5℃ / min and calcined for 2h. The activated carbon carrier was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 40%CFA-600-30-100-0.5.

[0059] Example 8

[0060] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon A8.

[0061] Prepare 150g of a saturated sodium fluoride solution with a concentration of 4.0 wt. / % and stir thoroughly until the sodium fluoride solid is completely dissolved.

[0062] After heating a saturated sodium fluoride solution to 70°C in an oil bath, 5g of activated carbon A8 was added at a solid-liquid ratio of 1:30. The treatment time was 2.0h, and the rotation speed was 600r·pm. After thorough stirring and reaction, the solution was washed until neutral and dried at 100°C for 10h. Then, the solution was calcined in a muffle furnace at a heating rate of 5°C / min to 300°C for 2h. The solution was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 4.0%CFNA-600-30-70-2.0.

[0063] Example 9

[0064] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon A9.

[0065] Prepare 150g of a saturated zinc fluoride solution with a concentration of 6.0 wt. / % and stir thoroughly until the zinc fluoride solid is completely dissolved.

[0066] After heating the saturated zinc fluoride solution to 70°C in an oil bath, 5g of activated carbon A9 was added at a solid-liquid ratio of 1:30. The treatment time was 0.5h, and the rotation speed was 600r·pm. After thorough stirring and reaction, the solution was washed until neutral and dried at 100°C for 10h. Then, the solution was calcined in a muffle furnace at a heating rate of 5°C / min to 300°C for 2h. The solution was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 6.0%CFZN-600-30-70-2.0.

[0067] Example 10

[0068] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon A10.

[0069] Prepare 150g of a saturated zirconium fluoride solution with a concentration of 1.4wt. / %, and stir thoroughly until the zirconium fluoride solid is completely dissolved.

[0070] After heating a saturated zirconium fluoride solution to 100°C in an oil bath, 5g of activated carbon A10 was added at a solid-liquid ratio of 1:30. The treatment time was 0.5h, and the rotation speed was 600r·pm. After thorough stirring and reaction, the solution was washed until neutral and dried at 100°C for 10h. Then, the solution was calcined in a muffle furnace at a heating rate of 5°C / min to 300°C for 2h. The solution was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 1.4%CFZR-600-30-100-0.5.

[0071] Example 11

[0072] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon A11.

[0073] Prepare 150g of a 22wt.% saturated fluorosilicic acid solution and stir thoroughly until fully mixed.

[0074] After heating the saturated fluorosilicic acid solution to 100℃ in an oil bath, 5g of activated carbon Al1 was added at a solid-liquid ratio of 1:30. The treatment time was 0.5h, the rotation speed was 600r·pm, and the reaction was stirred thoroughly. After washing until neutral, the solution was dried at 100℃ for 10h, then calcined in a muffle furnace at a heating rate of 5℃ / min to 300℃ for 2h. The solution was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 22%CFHSI-600-30-100-0.5.

[0075] Comparative Example 1

[0076] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon B1.

[0077] Weigh 150g of deionized water into a polytetrafluoroethylene bottle.

[0078] After heating deionized water to 70℃ in an oil bath, 5g of activated carbon B1 was added at a solid-liquid ratio of 1:30. The treatment time was 0.5h, the rotation speed was 600r·pm, and the reaction was stirred thoroughly. After washing until neutral, the activated carbon carrier was dried at 100℃ for 10h, then heated to 300℃ in a muffle furnace at a heating rate of 5℃ / min and calcined for 2h. The activated carbon carrier was then sieved into 10-20 mesh particles to obtain the activated carbon carrier after deionized water treatment, named OCW-600-30-70-0.5.

[0079] Comparative Example 2

[0080] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon B2.

[0081] Prepare 150g of a 40wt.% sodium hydroxide solution and stir thoroughly until the sodium hydroxide solid is completely dissolved.

[0082] S3: Post-treatment of activated carbon

[0083] After heating the sodium hydroxide solution to 70°C in an oil bath, 5g of activated carbon B2 was added at a solid-liquid ratio of 1:30. The treatment time was 0.5h, and the rotation speed was 600r·pm. After thorough stirring and reaction, the mixture was washed until neutral and dried at 100°C for 10h. Then, it was calcined in a muffle furnace at a heating rate of 5°C / min to 300°C for 2h. The calcined activated carbon was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 40%CNA-600-30-70-0.5.

[0084] Comparative Example 3

[0085] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon B4.

[0086] Prepare 150g of a 40wt.% nitric acid solution and stir thoroughly until homogeneous.

[0087] After heating the nitric acid solution to 70°C in an oil bath, 5g of activated carbon B4 was added at a solid-liquid ratio of 1:30. The treatment time was 0.5h, and the rotation speed was 600r·pm. After thorough stirring and reaction, the mixture was washed until neutral and dried at 100°C for 10h. Then, it was calcined in a muffle furnace at a heating rate of 5°C / min to 300°C for 2h. The calcined activated carbon was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 40%CHN-600-30-70-0.5.

[0088] Comparative Example 4

[0089] Coconut shell activated carbon was selected and cleaned with deionized water. The activated carbon was repeatedly filtered and washed three times until no floating matter was found, thus removing impurities. After drying at 100℃ for 10 hours, it was calcined in a muffle furnace at a heating rate of 5℃ / min to 350℃ for 2 hours to obtain activated carbon B6.

[0090] Prepare 150g of a 40wt.% zinc chloride solution and stir thoroughly until the zinc chloride solid is completely dissolved.

[0091] After heating the zinc chloride solution to 70°C in an oil bath, 5g of activated carbon B6 was added at a solid-liquid ratio of 1:30. The treatment time was 0.5h, and the rotation speed was 600r·pm. After thorough stirring and reaction, the solution was washed until neutral and dried at 100°C for 10h. Then, the solution was calcined in a muffle furnace at a heating rate of 5°C / min to 300°C for 2h. The solution was then sieved into 10-20 mesh particles to obtain the treated activated carbon carrier, named 40%CZNCL-600-30-70-0.5.

[0092] Application Example 1

[0093] This application example uses the hydrodehalogenation reaction of tetrachlorofluoroethane (R124) with Ni as the active catalyst component to evaluate the performance of the activated carbon catalyst supports prepared in the examples and comparative examples. However, the application of the activated carbon catalyst supports provided by this invention is not limited to this, and can also be applied to other hydrodehalogenation and dehydrohalogenation reactions.

[0094] Take 0.3g of the catalyst from the above examples and comparative examples and place it in a quartz tube with a length of 380mm and an inner diameter of 8mm. Place the catalyst on the copper grid in the middle of the reaction tube. After the reaction system is leak-tested, the catalyst is reduced and evaluated.

[0095] After purging with N2 atmosphere at 30 ml / min for 30 min, the catalyst pretreatment was started by introducing a mixture of N2 and H2 at 20 ml / min and reducing to 400℃ for 2 h at a heating rate of 10℃ / min.

[0096] After the catalyst completes its reduction, the temperature is lowered to the required reaction temperature, N2 is shut off, and feed gas and hydrogen are introduced to carry out the hydrodehalogenation reaction. The feed composition is 99.96 wt. / % R124, the reaction temperature is 350℃, and the R124 feed rate is 8 g·h. -1 The H2 flow rate is 35 mL·min -1 The products after the reaction were separated by condensation, washed with water and alkali, and analyzed by FID (Table 1).

[0097] Table 1. Content of reaction products from Ni-supported activated carbon used in the R124 hydrodehalogenation reaction.

[0098]

[0099]

[0100] As can be seen from Table 1, after treatment with fluoride or acid, both showed high conversion rates (reaching around 8%), but the stability after acid treatment was poor.

[0101] ICP composition analysis was performed on the activated carbon support after calcination (Table 2).

[0102] Table 2. ICP composition analysis after calcination treatment of activated carbon support.

[0103]

[0104] As can be seen from Table 2, fluoride treatment can effectively dissolve the content of various species in ash, especially for S and Ca species, the content is significantly reduced, which is difficult to dissolve by acid and alkali treatment.

[0105] The nitrogen adsorption-desorption test was performed on the activated carbon support (Table 3).

[0106] Table 3. Nitrogen adsorption-desorption tests on activated carbon carriers.

[0107]

[0108]

[0109] As can be seen from Table 3, the specific surface area and pore volume of the activated carbon carrier increased significantly after treatment, and it has a rich secondary pore structure, while the micropore structure was also preserved.

[0110] XRD testing (see appendix) Figure 1 The intensities of the two broad graphite peaks decreased significantly after fluoride treatment, indicating that fluoride treatment can disrupt the graphitization structure of the carbon support and increase its disorder. Simultaneously, Raman spectroscopy revealed that I... D / I G The increase in the ratio (Table 3) indicates an increase in the number of defect sites on the carbon support and a decrease in the degree of graphitization, which is consistent with the XRD results.

[0111] The NH3-TPD results (Table 3, with parent acid sites as 100%) show that the content of weak acid sites on the carbon support increased significantly after fluoride treatment; the content of acid sites on the carbon support decreased after alkali treatment; and in addition to the increase in weak acid sites, a small number of strong acid sites were also generated on the carbon support after acid treatment.

[0112] In summary, treating activated carbon catalyst supports with fluorides can effectively remove ash, generate abundant secondary pore structures, increase pore connectivity, and provide more weak acid sites and defect sites, which is beneficial for improving the initial conversion rate and stability of the hydrodehalogenation reaction. Moreover, the preparation process is simple and easy to prepare on a large scale.

Claims

1. A post-treatment method for activated carbon carriers, characterized in that: The post-processing method includes the following steps: S1: Pretreatment of activated carbon: The activated carbon is washed with water, dried and then calcined to obtain the first activated carbon carrier; S2: Post-treatment of activated carbon: After mixing and stirring the fluoride aqueous solution with the first activated carbon carrier, the second activated carbon carrier is obtained by washing, drying and calcining.

2. The post-treatment method for the activated carbon carrier according to claim 1, characterized in that: In step S1, the drying temperature is 50-100℃ and the drying time is 0.5-12h; the calcination temperature is 200-500℃, the heating rate is 2-10℃ / min, and the calcination time is 0.5-4h.

3. The post-treatment method for the activated carbon carrier according to claim 1, characterized in that: The concentration of the fluoride aqueous solution is 0.1–50.0 wt. / %.

4. The post-treatment method for the activated carbon carrier according to claim 3, characterized in that: The fluoride is selected from at least one of hydrogen fluoride, fluorosilicic acid, potassium fluoride, ammonium fluoride, sodium fluoride, zinc fluoride, and zirconium fluoride.

5. The post-treatment method for the activated carbon carrier according to claim 1, characterized in that: In step S2, the temperature during mixing and stirring of the fluoride aqueous solution and the first activated carbon carrier is 50–120°C, and the stirring time is 0.5–5 h.

6. The post-treatment method for the activated carbon carrier according to claim 1, characterized in that: The volume ratio of the first activated carbon carrier to the fluoride aqueous solution is 1:10 to 1:

40.

7. The post-treatment method for the activated carbon carrier according to claim 1, characterized in that: In step S2, the calcination temperature is 200-500℃, the heating rate is 2-10℃ / min, and the calcination time is 0.5-3h.

8. The post-treatment method for the activated carbon carrier according to claim 1, characterized in that: The activated carbon is selected from at least one of coal-based carbon, wood-based carbon, or fruit shell / kernel activated carbon.

9. An application of an activated carbon carrier, characterized in that: The second activated carbon support of any one of claims 1-8 is used as a catalyst support to load the catalyst active component.

10. The application of the activated carbon carrier according to claim 9, characterized in that: The second activated carbon support of any one of claims 1-8 is used as a catalyst support to support the active components of the catalyst for the hydrodehalogenation reaction.

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