Preparation method of composite adsorbent doped with high-temperature cracking insulator rubber powder

Abstract

The invention discloses a preparation method of a high-temperature cracking insulator rubber powder doped composite adsorbent, and belongs to the technical field of adsorption material preparation. The self-activation effect of a potassium citrate precursor is utilized, the magnesium oxide nanosheets with the space barrier effect are added, the magnesium oxide nanosheets can prevent carbon nanosheets derived from potassium citrate from being agglomerated, the PC-xMgO carbon material is synthesized in one step, and a micropore-mesopore structure is formed. The preparation method comprises the following steps: synthesizing gamma-Al2O3 containing a large amount of active sites by adopting a thermal decomposition method, doping gamma-Al2O3 and PC-xMgO into insulator powder subjected to high-temperature pyrolysis, and preparing a porous adsorbent for adsorbing SF6 gas by utilizing the insulator powder as a carrier, thereby achieving the purpose of efficiently adsorbing SF6. According to the invention, the waste insulator rubber is reasonably utilized to prepare the adsorbent with high adsorption performance, and the adsorbent can effectively adsorb SF6.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of adsorbent material preparation, and particularly relates to a preparation method of a high-temperature pyrolysis insulator rubber powder doped composite adsorbent. BACKGROUND

[0002] The composite insulator is composed of an outer sheath / umbrella skirt, an inner core rod and an end fitting. According to statistics, the number of composite insulators operating at a voltage level of 66 kV and above in China has exceeded 100 million, and the amount of silicone rubber waste has exceeded 700 million tons. By now, more than 4 million insulators have been in operation for more than 10 years, entering the middle and later stages of service life, and a large number of insulators will be retired in succession.

[0003] The insulator treatment and recycling methods mainly include physical methods and chemical methods. The chemical method can crack the insulating rubber through alkali catalysis, and the alkali can not only crack the Si-O-Si bond at high temperature, but also can crack a certain amount of Si-O bond, generating a cross-linked polymer structure in the linear siloxane alkali cracking process. The physical crushing method grinds the silicone rubber waste into powder through mechanical means, and uses the powder as a filler or a polymer to replace or partially replace the components in the original composite material, so as to effectively reduce the production cost and improve the added value of the silicone rubber waste. By optimizing the crushing process or surface modification treatment of the silicone rubber powder, the use amount of the powder can be further improved.

[0004] Sulfur hexafluoride (SF6) is an important insulating gas, which is widely used in high-voltage switch cabinets, circuit breakers and other electrical equipment. It has extremely high greenhouse effect potential and is one of the strongest greenhouse gases. Therefore, it is crucial to reduce its leakage and emission during production and use. Purifying SF6 by adsorbent can effectively dispose the leaked SF6 gas and reduce environmental pollution.

[0005] The commonly used SF6 adsorbents are mostly carbon-based adsorbents. The pore structure of activated carbon is relatively complex, the pore size distribution is wide, and the adsorption capacity of SF6 and its decomposition products is limited. The preparation process of carbon nanotubes is complex, and the cost is high, which limits its large-scale application. In addition, the carbon nanotubes are prone to agglomeration during preparation and use, which leads to a decrease in specific surface area and adsorption performance. The preparation process of graphene oxide is relatively complex, and needs to go through multiple steps such as oxidation and peeling, which is high in cost. The oxide of graphene oxide is prone to structural changes during adsorption, which leads to unstable adsorption performance. The silicon rubber material has a certain adsorption capacity, but the adsorption effect of some decomposition products (SO2, H2S, SOF2) is poor. The adsorption capacity of activated alumina to SF4 is strong, but after adsorbing a large amount of water, the adsorption capacity of activated alumina to low fluorides decreases. The adsorption performance of molecular sieve is good, and the adsorption capacity of water and low fluorides is large. Among them, the X-type molecular sieve has a certain adsorption capacity to SO2 and SO2F2, but after adsorbing SF4, the adsorption capacity of the X-type molecular sieve to SO2 and SO2F2 decreases. At present, there is no silicon rubber composite porous adsorbent with good adsorption effect in the prior art, especially the research on the preparation of adsorbents by using insulator rubber is less.

[0006] Therefore, there is an urgent need in the prior art for a new technical solution to solve this problem. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a preparation method of a high-temperature pyrolysis insulator rubber powder doped composite adsorbent, which is used to solve the technical problems of lack of adsorbents with high adsorption performance in the treatment of SF6 waste gas in the power industry and the need for recycling of waste insulator rubber in the prior art.

[0008] The technical solution adopted by the present application is to provide a preparation method of a high-temperature pyrolysis insulator rubber powder doped composite adsorbent, which comprises the following steps:

[0009] (1) Preparation of PC-xMgO carbon material:

[0010] A certain amount of MgO powder is weighed, and deionized water is added to boil and hydrolyze to generate Mg(OH)2, which is then dried and calcined at 300 DEG C to obtain activated MgO nanosheets. The MgO nanosheets and PC powder are weighed and mixed according to a predetermined molar ratio x, and then uniformly ground. The mixed powder is placed in a tube furnace, and the carbonization of PC and the in-situ self-activation process of potassium compounds are completed at high temperature under the protection of an inert atmosphere. At the same time, the MgO nanosheets play a role in space blocking to prevent the agglomeration of carbon nanosheets. After the reaction is completed, the furnace body is cooled to room temperature, and the product is taken out, soaked and washed with a dilute acid solution, and finally washed with deionized water until neutral and dried to obtain a porous PC-xMgO carbon material;

[0011] (2) Preparation of γ-Al2O3 nanopowder:

[0012] Under the condition of vigorous stirring, a certain concentration of aluminum ammonium sulfate aqueous solution was slowly added into ammonium bicarbonate aqueous solution, and aluminum ammonium carbonate precipitate was generated. In order to inhibit the agglomeration of ultra-fine particles, polyethylene glycol with a molecular weight of 6000 was added as a dispersant in the reaction system. After the reaction was completed, the obtained precipitate was aged, filtered, and washed with deionized water and anhydrous ethanol alternately for several times to remove impurity ions. Subsequently, the washed precursor was placed in a vacuum drying oven and dried at 50°C for 2 hours. Finally, the dried aluminum ammonium carbonate precursor was placed in a muffle furnace, and the temperature was programmed to rise to 850°C under air atmosphere, and calcined at this temperature for 2 hours. After natural cooling, the high-purity γ-Al2O3 nanopowder was obtained by grinding.

[0013] (3) Preparation of alkali-modified insulator-biochar composite porous carrier material by high-temperature calcination method:

[0014] After the waste silicone rubber insulator was crushed, it was placed in a ball mill with zirconia balls as the grinding medium. The ball-to-material ratio and rotation speed were controlled to grind the insulator rubber powder to a uniform particle size distribution in the 60-100 mesh interval. The insulator rubber powder, active biochar powder, and sodium hydroxide solid were accurately weighed according to a certain mass ratio and mixed uniformly in a mixer. The mixture was transferred to a corundum crucible and placed in a muffle furnace. The temperature was programmed to rise to 500-700°C under air atmosphere, and calcined at this temperature for 2 hours. After the reaction was completed, the product was naturally cooled to room temperature. After crushing, grinding, and sieving, the alkali-modified insulator-biochar composite porous carrier material was obtained.

[0015] (4) Preparation of insulator rubber powder doped with PC-xMgO@γ-Al2O3 composite adsorbent:

[0016] A certain amount of PC-xMgO carbon material, γ-Al2O3 nanopowder, and alkali-modified insulator-biochar composite porous carrier material were weighed into a beaker, and an appropriate amount of deionized water was added and stirred to form a uniform slurry. The slurry was placed in a 30°C constant-temperature water bath and reacted for 4 hours under magnetic stirring to ensure that the components were fully mixed and loaded. Subsequently, the mixture was dried at 100°C for 2 hours to remove water. The dried block product was ground into powder and transferred to a corundum crucible. The crucible was placed in a muffle furnace and programmed to rise to 400°C at a rate of 10°C / min under air atmosphere. The temperature was held at this value for 4 hours. This heat treatment process aimed to remove residual organic matter, strengthen the combination between components, and finally shape. After the calcination was completed, the furnace was naturally cooled to room temperature, and the product was removed. The product was ground again and sieved through a 200-mesh sieve to obtain the final insulator rubber powder doped with PC-xMgO@γ-Al2O3 porous adsorbent.

[0017] The value of x in step (1) is 0.5, 1, 1.5, respectively.

[0018] The conditions of carbonization and in-situ self-activation in step (1) are programmed to rise to 750 DEG C and keep for 1.5 hours.

[0019] The molar ratio of aluminum ammonium sulfate to ammonium bicarbonate in step (2) is 1:3.

[0020] The reaction temperature of aluminum ammonium sulfate and ammonium bicarbonate in step (2) is 30 DEG C.

[0021] The rotation speed of the ball mill for grinding the insulator rubber powder in step (3) is 500 r / min, and the forward and reverse rotation time is 30 min, respectively, and the repetition is 3 times.

[0022] The mass ratio of the insulator rubber powder, active biochar powder and sodium hydroxide solid in step (3) is 4:1:1.

[0023] The mass ratio of PC-xMgO carbon material, gamma-Al2O3 nano powder and alkali modified insulator-biochar composite porous carrier material in step (4) is 1:1:3.

[0024] Application of the high-temperature pyrolysis insulator rubber powder doped composite adsorbent prepared by the preparation method to SF6 waste gas treatment.

[0025] The above design scheme can bring the following beneficial effects:

[0026] 1. The self-activation of the potassium citrate (PC) precursor is utilized, and the magnesium oxide (MgO) nanosheet with a space blocking effect is added, the MgO can prevent the agglomeration of the PC derived carbon nanosheet, the PC-xMgO carbon material is synthesized in one step, the microporous-mesoporous structure is formed, the optimal balance between the gas adsorption capacity, the separation selectivity and the diffusion rate is realized by the combination of the limited effect of the micropore and the diffusion characteristics of the mesopore;

[0027] 2. The gamma-Al2O3 containing a large number of active sites is synthesized by the thermal decomposition method, and the polyethylene glycol is used as a dispersant to reduce the agglomeration of the superfine particles in the reaction;

[0028] 3. In the high-temperature pyrolysis process of the insulator powder, the NaOH is used as an activator, reacts with the silicone rubber and biochar in the insulator at high temperature, etches to generate water glass (Na2SiO3) and creates a large number of pores;

[0029] 4. The PC-xMgO@γ-Al2O3 is doped into the high-temperature pyrolysis insulator powder, and the porous adsorbent is prepared by using the insulator powder as a carrier to adsorb SF6 gas, so as to achieve the purpose of high-efficiency adsorption of SF6, and the adsorption capacity reaches 0.48 mg / g. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The infrared spectrum of the adsorbent of the preparation method of the high-temperature pyrolysis insulator rubber powder doped composite adsorbent of the application is shown in the figure;

[0031] Figure 2 The thermogravimetric analysis diagram of the adsorbent of the preparation method of the high-temperature pyrolysis insulator rubber powder doped composite adsorbent of the application is shown in the figure;

[0032] Figure 3 The BET diagram of the adsorbent of the preparation method of the high-temperature pyrolysis insulator rubber powder doped composite adsorbent of the application is shown in the figure;

[0033] Figure 4 The SEM diagram of the adsorbent of the preparation method of the high-temperature pyrolysis insulator rubber powder doped composite adsorbent of the application is shown in the figure. DETAILED DESCRIPTION

[0034] The application will be further described below in combination with the drawings and specific embodiments:

[0035] The adsorbent in the following examples is prepared on the spot.

[0036] Example 1: A preparation method of a high-temperature pyrolysis insulator rubber powder doped composite adsorbent, comprising the following steps:

[0037] (1) PC-xMgO carbon material is prepared by self-activation:

[0038] Mg(OH)2 is formed by boiling MgO powder, and then MgO nanosheets are prepared by calcining at 300°C to remove water. 5g of MgO nanosheets are mixed with 38.25g of potassium citrate (PC) powder, and after being fully ground, carbonization and in-situ self-activation are carried out at 750°C under an inert atmosphere. After acid washing, PC-1MgO (the molar ratio of MgO to PC is 1) carbon material is obtained.

[0039] (2) Preparation of γ-Al2O3 nano powder:

[0040] 0.5 L of 0.2 mol / L aluminum ammonium sulfate ((NH4)Al(SO4)2·12H2O) aqueous solution was dropped into 0.5 L of 0.6 mol / L ammonium bicarbonate (NH4HCO3) aqueous solution under vigorous stirring, and a magnetic stirrer was used for stirring. In order to reduce the agglomeration of ultra-fine particles generated in the reaction, 2.76 g of polyethylene glycol dispersant was added to the solution for reaction, and the reactant was washed with deionized water and anhydrous ethanol, and then vacuum dried at 50°C. The synthesized aluminum ammonium carbonate was used as raw material and placed in a muffle furnace at 850°C for 2h to obtain γ-Al2O3 nanopowder.

[0041] (3) Preparation of alkali-modified insulator-biochar composite porous carrier material by high-temperature calcination method:

[0042] The silicone rubber insulator was placed in a ball mill for ball milling to prepare insulator powder. The particle size of the insulator rubber powder after ball milling was 60-100 mesh. The insulator rubber powder, active biochar powder and NaOH were mixed in a mass ratio of 4:1:1 and placed in a muffle furnace at 850°C for 2h. After cooling to room temperature, the alkali-modified insulator-biochar composite porous carrier material was obtained after crushing, grinding and sieving.

[0043] (4) Preparation of PC-xMgO@γ-Al2O3 doped adsorbent:

[0044] A certain amount of PC-xMgO, γ-Al2O3 and insulator rubber powder was weighed into a beaker (PC-xMgO 2g, γ-Al2O3 2g, insulator powder 6g), and an appropriate amount of deionized water was measured and stirred to form a uniform slurry. The slurry was placed in a magnetic stirrer and stirred at 30°C for 4h. After stirring, the sample was dried at 100°C for 2h, ground, placed in a crucible, and calcined in a muffle furnace with a heating rate of 10°C / min, a calcination temperature of 400°C and a calcination time of 4h. After calcination, the product was taken out and ground in a mortar, and sieved using a 200 mesh sieve to obtain an insulator rubber powder doped PC-xMgO@γ-Al2O3 porous adsorbent.

[0045] Example 2: A method for preparing a high-temperature pyrolysis insulator rubber powder doped composite adsorbent, comprising the following steps:

[0046] (1) Preparation of PC-xMgO carbon material by self-activation:

[0047] MgO nanoplatelets were prepared by boiling MgO powder to form Mg(OH)2, and then calcining at 300 °C to remove water. 5 g of MgO nanoplatelets were mixed with 38.25 g of potassium citrate (PC) powder, and after grinding, carbonization and in-situ self-activation were carried out at 750 °C under an inert atmosphere. After acid washing, PC-1MgO (molar ratio of MgO to PC is 1) carbon material was obtained.

[0048] (2) Preparation of γ-Al2O3 nanopowder:

[0049] 0.5 L of 0.2 mol / L aluminum ammonium sulfate ((NH4)Al(SO4)2·12H2O) aqueous solution was dropped into 0.5 L of 0.6 mol / L ammonium bicarbonate (NH4HCO3) aqueous solution under vigorous stirring, and a magnetic stirrer was used for stirring. To reduce the agglomeration of ultra-fine particles generated in the reaction, 2.76 g of polyethylene glycol dispersant was added to the solution for reaction, and the reaction product was washed with deionized water and anhydrous ethanol, and then vacuum dried at 50 °C. The synthesized aluminum ammonium carbonate was used as raw material and placed in a muffle furnace for 2 h at 850 °C to obtain γ-Al2O3 nanopowder.

[0050] (3) Preparation of alkali-modified insulator-biochar composite porous carrier material by high-temperature calcination:

[0051] Silicone rubber insulators were placed in a ball mill for ball milling to prepare insulator powder, and the particle size of the ball-milled insulator rubber powder was 60-100 mesh. The insulator rubber powder, active biochar powder, and NaOH were mixed in a mass ratio of 3:1:1, and then placed in a muffle furnace for calcination at 850 °C for 2 h. After cooling to room temperature, the product was broken, ground, and sieved to obtain the alkali-modified insulator-biochar composite porous carrier material.

[0052] (4) Preparation of PC-xMgO@γ-Al2O3 doped adsorbent:

[0053] A certain amount of PC-xMgO, γ-Al2O3, and insulator rubber powder were weighed into a beaker (PC-xMgO 2 g, γ-Al2O3 2 g, and insulator powder 6 g), and an appropriate amount of deionized water was measured and stirred to form a uniform slurry. The slurry was placed in a magnetic stirrer and stirred at 30 °C for 4 h. After stirring, the sample was dried at 100 °C for 2 h, then ground and placed in a crucible. The muffle furnace was used for calcination, with a heating rate of 10 °C / min, a calcination temperature of 400 °C, and a calcination time of 4 h. After calcination, the furnace was naturally cooled to room temperature, and the product was removed. The product was ground using a mortar and sieved using a 200 mesh sieve to obtain the insulator rubber powder doped PC-xMgO@γ-Al2O3 porous adsorbent.

[0054] Example 3: A method for preparing a high-temperature pyrolysis insulator rubber powder doped composite adsorbent, comprising the following steps:

[0055] (1) Preparation of PC-xMgO carbon material by self-activation:

[0056] MgO powder was boiled to form Mg(OH)2, and then calcined at 300°C to remove water to prepare MgO nanosheets. 5 g of MgO nanosheets were mixed with 38.25 g of potassium citrate (PC) powder, and after being ground well, carbonization and in-situ self-activation were carried out at 750°C under an inert atmosphere. After acid washing, PC-1MgO (molar ratio of MgO to PC is 1) carbon material was obtained.

[0057] (2) Preparation of γ-Al2O3 nano powder:

[0058] 0.5 L of 0.2 mol / L aluminum ammonium sulfate ((NH4)Al(SO4)2·12H2O) aqueous solution was added dropwise into 0.5 L of 0.6 mol / L ammonium bicarbonate (NH4HCO3) aqueous solution under vigorous stirring, and a magnetic stirrer was used for stirring. To reduce the agglomeration of ultra-fine particles generated in the reaction, 2.76 g of polyethylene glycol dispersant was added to the solution for reaction, and the reaction product was washed with deionized water and anhydrous ethanol, and then vacuum dried at 50°C. The synthesized aluminum ammonium carbonate was used as raw material and placed in a muffle furnace for 2 h at 850°C to obtain γ-Al2O3 nano powder.

[0059] (3) Preparation of alkali-modified insulator-biochar composite porous carrier material by high-temperature calcination:

[0060] Silicone rubber insulators were placed in a ball mill for ball milling to prepare insulator powder, and the particle size of the insulator rubber powder after ball milling was 60-100 mesh. The insulator rubber powder, active biochar powder, and NaOH were mixed in a mass ratio of 5:1:1, and then placed in a muffle furnace for calcination at 850°C for 2 h. After cooling to room temperature, the alkali-modified insulator-biochar composite porous carrier material was obtained after crushing, grinding, and sieving.

[0061] (4) Preparation of PC-xMgO@γ-Al2O3 doped adsorbent:

[0062] A certain amount of PC-xMgO, γ-Al2O3 and insulator rubber powder is weighed into a beaker (PC-xMgO 2 g, γ-Al2O3 2 g, insulator powder 6 g), an appropriate amount of deionized water is measured and stirred to make a uniform slurry, and the slurry is placed in a magnetic stirrer and stirred at 30°C for 4 h. After stirring, the sample is dried at 100°C for 2 h, ground, placed in a crucible, and calcined in a muffle furnace with a heating rate of 10°C / min, a calcination temperature of 400°C, and a calcination time of 4 h. After calcination, the furnace is naturally cooled to room temperature, the product is removed, ground with a mortar, and sieved with a 200-mesh sieve to obtain an insulator rubber powder doped with PC-xMgO@γ-Al2O3 porous adsorbent.

[0063] Example 4: A method for preparing a high-temperature pyrolysis insulator rubber powder doped composite adsorbent, comprising the following steps:

[0064] (1) Preparation of PC-xMgO carbon material by self-activation:

[0065] MgO powder is boiled to form Mg(OH)2, which is then calcined at 300°C to remove water and prepare MgO nanosheets. 1 g of MgO nanosheets is mixed with 15.3 g of potassium citrate (PC) powder, ground thoroughly, and then carbonized and in-situ self-activated at 750°C under an inert atmosphere. After acid washing, PC-0.5MgO (MgO to PC molar ratio of 0.5) carbon material is obtained.

[0066] (2) Preparation of γ-Al2O3 nano powder:

[0067] 0.5 L of 0.2 mol / L aluminum sulfate ammonium ((NH4)Al(SO4)2·12H2O) aqueous solution is added dropwise to 0.5 L of 0.6 mol / L ammonium bicarbonate (NH4HCO3) aqueous solution under vigorous stirring, and a magnetic stirrer is used for stirring. To reduce the agglomeration of ultra-fine particles generated during the reaction, 2.76 g of polyethylene glycol dispersant is added to the solution for reaction, and the reaction product is washed with deionized water and anhydrous ethanol, and then vacuum dried at 50°C. The synthesized aluminum ammonium carbonate is used as raw material and placed in a muffle furnace for 2 h at 850°C to obtain γ-Al2O3 nano powder.

[0068] (3) Preparation of alkali-modified insulator-biochar composite porous carrier material by high-temperature calcination:

[0069] The silicone rubber insulator was put into a ball mill for ball milling to prepare insulator powder, and the particle size of the insulator rubber powder after ball milling was 60-100 mesh. The insulator rubber powder, activated biochar powder and NaOH were mixed in a mass ratio of 4:1:1, and then put into a muffle furnace and calcined at 850°C for 2h. After cooling to room temperature, the alkali-modified insulator-biochar composite porous carrier material was obtained after crushing, grinding and sieving.

[0070] (4) Preparation of adsorbent doped with PC-xMgO@γ-Al2O3:

[0071] A certain amount of PC-xMgO, γ-Al2O3 and insulator rubber powder were weighed and placed in a beaker (PC-xMgO 2g, γ-Al2O3 2g, insulator powder 6g). An appropriate amount of deionized water was measured and stirred to form a uniform slurry. The slurry was placed in a magnetic stirrer and stirred at 30°C for 4h. After stirring, the sample was dried at 100°C for 2h, then ground and placed in a crucible. The muffle furnace was used for calcination, with a heating rate of 10°C / min, a calcination temperature of 400°C and a calcination time of 4h. After calcination, the product was taken out and ground with a mortar. A 200 mesh sieve was used for sieving, and the insulator rubber powder doped with PC-xMgO@γ-Al2O3 porous adsorbent was obtained.

[0072] Example 5: A method for preparing a high-temperature pyrolysis insulator rubber powder doped composite adsorbent, comprising the following steps:

[0073] (1) Preparation of PC-xMgO carbon material by self-activation:

[0074] Mg(OH)2 was formed by boiling MgO powder, and then MgO nanosheets were prepared by calcining at 300°C to remove water. 2g of MgO nanosheets were mixed with 10.2g of potassium citrate (PC) powder, and then carbonized and in-situ self-activated at 750°C under an inert atmosphere. After acid washing, PC-1.5MgO (molar ratio of MgO to PC is 1.5) carbon material was obtained.

[0075] (2) Preparation of γ-Al2O3 nanoscale powder:

[0076] 0.5 L of 0.2 mol / L aluminum ammonium sulfate ((NH4)Al(SO4)2·12H2O) aqueous solution was dropped into 0.5 L of 0.6 mol / L ammonium bicarbonate (NH4HCO3) aqueous solution under vigorous stirring, and a magnetic stirrer was used for stirring. In order to reduce the agglomeration of ultra-fine particles generated in the reaction, 2.76 g of polyethylene glycol dispersant was added to the solution for reaction, and the reactant was washed with deionized water and anhydrous ethanol, and then vacuum dried at 50°C. The synthesized aluminum ammonium carbonate was used as raw material and placed in a muffle furnace for calcination at 850°C for 2h to obtain γ-Al2O3 nanopowder.

[0077] (3) Preparation of alkali-modified insulator-biochar composite porous carrier material by high-temperature calcination method:

[0078] The silicone rubber insulator was placed in a ball mill for ball milling to prepare insulator powder, and the particle size of the insulator rubber powder after ball milling was 60-100 mesh. The insulator rubber powder, active biochar powder and NaOH were mixed in a mass ratio of 4:1:1, placed in a muffle furnace and calcined at 850°C for 2h, then cooled to room temperature, crushed, ground and sieved to obtain the alkali-modified insulator-biochar composite porous carrier material.

[0079] (4) Preparation of PC-xMgO@γ-Al2O3 doped adsorbent:

[0080] A certain amount of PC-xMgO, γ-Al2O3 and insulator rubber powder was weighed into a beaker (PC-xMgO 2g, γ-Al2O3 2g, insulator powder 6g), an appropriate amount of deionized water was measured and stirred to form a uniform slurry, and the slurry was placed in a magnetic stirrer and stirred at 30°C for 4h. After stirring, the sample was dried at 100°C for 2h, ground, placed in a crucible, and calcined in a muffle furnace with a heating rate of 10°C / min, a calcination temperature of 400°C and a calcination time of 4h. After calcination, the furnace body was naturally cooled to room temperature, the product was taken out, ground with a mortar, and sieved with a 200 mesh sieve to obtain an insulator rubber powder doped PC-xMgO@γ-Al2O3 porous adsorbent.

[0081] Example 6: A preparation method of a high-temperature pyrolysis insulator rubber powder doped composite adsorbent, comprising the following steps:

[0082] (1) Preparation of PC-xMgO carbon material by self-activation:

[0083] MgO nanoplatelets were prepared by boiling MgO powder to form Mg(OH)2, and then calcining at 300 °C to remove water. 5 g of MgO nanoplatelets were mixed with 38.25 g of potassium citrate (PC) powder, and after grinding, carbonization and in-situ self-activation were carried out at 650 °C under an inert atmosphere. After acid washing, PC-1MgO (molar ratio of MgO to PC is 1) carbon material was obtained.

[0084] (2) Preparation of γ-Al2O3 nanopowder:

[0085] 0.5 L of 0.2 mol / L aluminum ammonium sulfate ((NH4)Al(SO4)2·12H2O) aqueous solution was dropped into 0.5 L of 0.6 mol / L ammonium bicarbonate (NH4HCO3) aqueous solution under vigorous stirring, and a magnetic stirrer was used for stirring. To reduce the agglomeration of ultra-fine particles generated in the reaction, 2.76 g of polyethylene glycol dispersant was added to the solution for reaction, and the reaction product was washed with deionized water and anhydrous ethanol, and then vacuum dried at 50 °C. The synthesized aluminum ammonium carbonate was used as raw material and placed in a muffle furnace for 2 h at 850 °C to obtain γ-Al2O3 nanopowder.

[0086] (3) Preparation of alkali-modified insulator-biochar composite porous carrier material by high-temperature calcination:

[0087] Silicone rubber insulators were placed in a ball mill for ball milling to prepare insulator powder, and the particle size of the ball-milled insulator rubber powder was 60-100 mesh. The insulator rubber powder, active biochar powder, and NaOH were mixed in a mass ratio of 4:1:1, and then placed in a muffle furnace for calcination at 850 °C for 2 h. After cooling to room temperature, the product was broken, ground, and sieved to obtain the alkali-modified insulator-biochar composite porous carrier material.

[0088] (4) Preparation of PC-xMgO@γ-Al2O3 doped adsorbent:

[0089] A certain amount of PC-xMgO, γ-Al2O3, and insulator rubber powder were weighed into a beaker (PC-xMgO 2 g, γ-Al2O3 2 g, and insulator powder 6 g), and an appropriate amount of deionized water was measured and stirred to form a uniform slurry. The slurry was placed in a magnetic stirrer and stirred at 30 °C for 4 h. After stirring, the sample was dried at 100 °C for 2 h, then ground and placed in a crucible. The muffle furnace was used for calcination, with a heating rate of 10 °C / min, a calcination temperature of 400 °C, and a calcination time of 4 h. After calcination, the furnace was naturally cooled to room temperature, and the product was removed. The product was ground using a mortar and sieved using a 200 mesh sieve to obtain the insulator rubber powder doped PC-xMgO@γ-Al2O3 porous adsorbent.

[0090] Example 7: A method for preparing a high-temperature pyrolysis insulator rubber powder doped composite adsorbent, comprising the following steps:

[0091] (1) Preparation of PC-xMgO carbon material by self-activation:

[0092] MgO nanoplates were prepared by boiling with MgO powder to form Mg(OH)2, and then calcining at 300°C to remove water. 5 g of MgO nanoplates were mixed with 38.25 g of potassium citrate (PC) powder, and after grinding, carbonization and in-situ self-activation were carried out at 850°C under an inert atmosphere. After acid washing, PC-1MgO (molar ratio of MgO to PC is 1) carbon material was obtained.

[0093] (2) Preparation of γ-Al2O3 nanopowder:

[0094] 0.5 L of 0.2 mol / L aluminum ammonium sulfate ((NH4)Al(SO4)2·12H2O) aqueous solution was added dropwise to 0.5 L of 0.6 mol / L ammonium bicarbonate (NH4HCO3) aqueous solution under vigorous stirring, and a magnetic stirrer was used for stirring. To reduce the agglomeration of ultrafine particles generated during the reaction, 2.76 g of polyethylene glycol dispersant was added to the solution for reaction, and the reaction product was washed with deionized water and anhydrous ethanol, and then vacuum dried at 50°C. The synthesized aluminum ammonium carbonate was used as raw material and placed in a muffle furnace for 2 h at 850°C to obtain γ-Al2O3 nanopowder.

[0095] (3) Preparation of alkali-modified insulator-biochar composite porous carrier material by high-temperature calcination:

[0096] Silicone rubber insulators were placed in a ball mill for ball milling to prepare insulator powder, and the particle size of the ball-milled insulator rubber powder was 60-100 mesh. The mass ratio of insulator rubber powder, activated biochar powder and NaOH was 4:1:1, and they were mixed uniformly and placed in a muffle furnace for calcination at 850°C for 2 h. After cooling to room temperature, the alkali-modified insulator-biochar composite porous carrier material was obtained after crushing, grinding and sieving.

[0097] (4) Preparation of PC-xMgO@γ-Al2O3 doped adsorbent:

[0098] A certain amount of PC-xMgO, γ-Al2O3 and insulator rubber powder was placed in a beaker (PC-xMgO 2 g, γ-Al2O3 2 g, insulator powder 6 g), and a suitable amount of deionized water was measured and stirred to form a uniform slurry. The slurry was placed in a magnetic stirrer and stirred at 30°C for 4 h. After stirring, the sample was dried at 100°C for 2 h, then ground, placed in a crucible, and calcined in a muffle furnace at a heating rate of 10°C / min, a calcination temperature of 400°C, and a calcination time of 4 h. After calcination, the furnace was allowed to cool to room temperature naturally, and the product was removed, ground in a mortar, and sieved using a 200-mesh sieve to obtain an insulator rubber powder doped with PC-xMgO@γ-Al2O3 porous adsorbent.

[0099] In Examples 1-7, carbonization and in-situ self-activation were carried out by adjusting the calcination temperature in step (1) under an inert atmosphere. The optimal porosity was determined by adjusting the mass ratio of insulator rubber powder to active biochar powder in step (3).

[0100] In Examples 1-7, the adsorption capacity of sulfur hexafluoride is shown in Table 1.

[0101] Table 1 Sulfur hexafluoride adsorption capacity table

[0102] Indicator Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Breakthrough time (h) 0.3 0.27 0.21 0.23 0.31 0.25 0.26 Dynamic adsorption capacity (mg / g) 0.46 0.42 0.33 0.36 0.48 0.40 0.41

[0103] From Figure 1 It can be seen that in the infrared spectrum of the silicone rubber / PC-xMgO, the absorption peaks at 3700 cm -1 , 1684 cm -1 , and 1318 cm -1 correspond to the stretching vibrations of -OH, C=O, and C-O. In the infrared spectrum of the silicone rubber / PC-xMgO@γ-Al2O3, the characteristic peaks at 1680 cm -1 and 1300 cm -1 correspond to the stretching vibrations of C-O, and the obvious characteristic peak at 2360 cm -1 corresponds to the stretching vibrations of Si-H. The absorption peak of PC-xMgO and PC-xMgO@γ-Al2O3 at 1680 cm -1 is stronger than that of the silicone rubber powder, which can be attributed to the stretching vibrations of the C=O bond of PC. In the infrared spectrum of the silicone rubber, there is a broad peak near 3000 cm -1 , which is related to the stretching vibrations of C-H. There are multiple peaks below 1500 cm -1 , which may be related to the vibrations of silicon-oxygen bonds (Si-O). Compared with pure silicone rubber, in the infrared spectrum of the silicone rubber / PC-MgO, the spectrum has a peak at 3000 cm -1The absorption peaks nearby show slight changes, possibly due to the introduction of MgO. At 1500 cm⁻¹ -1 The following changes in absorption peaks may be due to the interaction between MgO and the silicone rubber matrix. In the infrared spectrum of silicone rubber / PC-MgO@AL2O3, the peak value at 3000 cm⁻¹ is [missing value]. -1 The change in the nearby characteristic peaks may be due to the introduction of Al2O3.

[0104] Depend on Figure 2 It is evident that the adsorbent material exhibits significant thermal stability; its mass gradually decreases with increasing temperature, indicating decomposition or volatilization during heating. Between 0 and 183°C, the sample mass decreases rapidly, likely due to the evaporation of moisture or other low-boiling-point components. Between 183 and 453°C, the mass continues to decrease, but at a slower rate, possibly indicating the decomposition of organic components or other chemical reactions. Above 453°C, the sample mass decreases significantly again, possibly due to further decomposition of remaining organic components or other elements. At 600°C, the sample mass decreases to approximately 82%, representing a loss of about 18% of its mass at this temperature.

[0105] Depend on Figure 3 It can be seen that at lower relative pressures (P / P0 < 0.1), the adsorption capacity increases slowly, which is usually related to micropore filling. With increasing relative pressure, the adsorption capacity gradually increases, especially when the relative pressure approaches 1, where the adsorption capacity increases sharply, indicating that the material may have a large pore structure. The desorption and adsorption curves essentially overlap in the low relative pressure region; however, at higher relative pressures (P / P0 > 0.4), a significant hysteresis phenomenon begins to appear. This phenomenon is usually related to the size and shape of the pore structure, especially in mesoporous and macroporous materials. The hysteresis loop appears between relative pressures of 0.4 and 0.9, indicating the presence of mesopores (pore size between 2 and 50 nm) in the material. This indicates that the prepared adsorbent material is a porous material with a mesoporous structure.

[0106] Depend on Figure 4 As can be seen, the sample surface exhibits an irregular blocky structure, with particles of varying sizes and shapes. The particle surfaces are rough and porous, possibly due to the porous nature of the material or formed during the preparation process. On the scale, the larger particles may have diameters in the range of tens of micrometers, while the smaller particles and debris may range in size from a few micrometers to tens of micrometers.

[0107] The implementation of the present invention is not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and are included within the protection scope of the present invention.

Claims

1. A process for the preparation of a high temperature pyrolytic insulator rubber powder doped composite adsorbent, characterized by: Comprising the following steps: (1) Preparation of PC-xMgO carbon material: A certain mass of MgO powder is weighed, deionized water is added to boil and hydrolyze it to generate Mg(OH)2, and then after drying, calcination is carried out at 300°C to obtain activated MgO nanosheets. The MgO nanosheets are weighed and mixed with PC powder according to a preset molar ratio x, and after being fully ground and uniformly mixed, the mixed powder is placed in a tube furnace to complete the carbonization of PC and the in-situ self-activation process of potassium compounds at high temperature under the protection of an inert atmosphere. The MgO nanosheets play a role in spatial blocking to prevent the agglomeration of carbon nanosheets. After the reaction is completed, the furnace body is cooled to room temperature, the product is taken out, soaked and washed with a dilute acid solution, and finally washed with deionized water until neutral and dried to obtain a porous PC-xMgO carbon material; (2) Preparation of γ-Al2O3 nano powder: Under vigorous stirring, an aluminum ammonium sulfate aqueous solution of a certain concentration is slowly added to an ammonium bicarbonate aqueous solution. To inhibit the agglomeration of ultra-fine particles, a polyethylene glycol with a molecular weight of 6000 is added as a dispersant to the reaction system. After the reaction is completed, the obtained precipitate is aged, filtered, and washed several times with deionized water and anhydrous ethanol to remove impurity ions. Then, the washed precursor is placed in a vacuum drying oven and dried at 50°C for 2 hours. Finally, the dried ammonium aluminate precursor is placed in a muffle furnace, heated to 850°C in an air atmosphere, and calcined at this temperature for 2 hours. After natural cooling, the high-purity γ-Al2O3 nano powder is obtained by grinding; (3) Preparation of alkali-modified insulator-biochar composite porous carrier material by high-temperature sintering method: After the waste silicone rubber insulator is crushed, it is placed in a ball mill with zirconia balls as the grinding medium. The ball-to-material ratio and rotation speed are controlled to grind the powder to a uniform particle size distribution in the 60-100 mesh interval to obtain insulator rubber powder. The insulator rubber powder, activated biochar powder, and sodium hydroxide solid are accurately weighed and mixed in a mixer. The mixture is transferred to a corundum crucible and placed in a muffle furnace. The temperature is programmed to 500-700°C in an air atmosphere, and calcination is carried out at this temperature for 2 hours. After the reaction is completed, the product is naturally cooled to room temperature, crushed, ground, and sieved to obtain an alkali-modified insulator-biochar composite porous carrier material; (4) Preparation of insulator rubber powder doped with PC-xMgO@γ-Al2O3 composite adsorbent: A certain amount of PC-xMgO carbon material, γ-Al2O3 nanopowder and alkali-modified insulator-biochar composite porous carrier material were weighed into a beaker, an appropriate amount of deionized water was added and stirred to form a uniform slurry, the slurry was placed in a 30°C constant temperature water bath, and stirred under magnetic stirring for 4 hours to ensure that the components were fully mixed and loaded. Subsequently, the mixture was dried at 100°C for 2 hours to remove water, and the dried block product was ground into powder and transferred to a corundum crucible, which was placed in a muffle furnace and programmed to heat to 400°C at a heating rate of 10°C / min under an air atmosphere, and calcined at this temperature for 4 hours. The heat treatment process was designed to remove residual organic matter, strengthen the combination between components and finally shape. After calcination, the product was removed after the furnace body was naturally cooled to room temperature, ground again and passed through a 200 mesh sieve to obtain the final insulator rubber powder doped with PC-xMgO@γ-Al2O3 porous adsorbent.

2. A process for the preparation of a high temperature pyrolytic insulator rubber powder doped composite adsorbent as claimed in claim 1, wherein: In step (1), x is 0.5, 1, and 1.5, respectively.

3. The method for preparing a composite adsorbent doped with high-temperature pyrolysis insulator rubber powder according to claim 1, characterized in that: In step (1), the conditions for carbonization and in-situ self-activation are programmed to heat to 750°C and hold for 1.5 hours.

4. The method for preparing a composite adsorbent doped with high-temperature pyrolysis insulator rubber powder according to claim 1, characterized in that: In step (2), the molar ratio of aluminum ammonium sulfate to ammonium bicarbonate is 1:

3.

5. The method for preparing a composite adsorbent doped with high-temperature pyrolysis insulator rubber powder according to claim 1, characterized in that: In step (2), the reaction temperature of aluminum ammonium sulfate and ammonium bicarbonate is 30°C.

6. The method for preparing a composite adsorbent doped with high-temperature pyrolysis insulator rubber powder according to claim 1, characterized in that: In step (3), the rotation speed of the ball mill for grinding the insulator rubber powder is 500 r / min, and the forward and reverse rotation times are 30 min each, repeated 3 times.

7. The method for preparing a composite adsorbent doped with high-temperature pyrolysis insulator rubber powder according to claim 1, characterized in that: In step (3), the mass ratio of insulator rubber powder, activated biochar powder and sodium hydroxide solid is 4:1:

1.

8. The method for preparing a composite adsorbent doped with high-temperature pyrolysis insulator rubber powder according to claim 1, characterized in that: In step (4), the mass ratio of PC-xMgO carbon material, γ-Al2O3 nanopowder and alkali-modified insulator-biochar composite porous carrier material is 1:1:

3.

9. The application of the high-temperature pyrolysis insulator rubber powder doped composite adsorbent prepared by the preparation method of any one of claims 1-8 in SF6 waste gas treatment.

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