Method for evaluating co2 adsorption performance of waste tire-based adsorbent

Abstract

The present application relates to the technical field of tire rubber recycling, and particularly relates to a method for evaluating the CO2 adsorption performance of a waste tire-based adsorbent, which uses waste tires as a raw material, combines the complex characteristics of waste tire components, and selectively uses an activation test. A two-step activation method of chemical activation and physical activation is used to prepare a waste tire-based adsorbent for adsorbing CO2, which has low cost, high adsorption capacity and good regeneration performance. Then, the highest limit of the waste tire-based adsorbent adsorbing CO2 under standard conditions (1 atm, 0 DEG C) is judged by the thermodynamic parameter Gibbs free energy. Meanwhile, the present application proposes a thermodynamic excellent index delta of the adsorbent adsorbing CO2, which is a thermodynamic index for evaluating the adsorption capacity of the waste tire-based adsorbent adsorbing CO2. The present application can effectively and accurately analyze the adsorption performance of the prepared tire-based adsorbent, so as to select the optimal production process and improve the production efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tire rubber recycling, and particularly relates to a method for evaluating the CO2 adsorption performance of a waste tire-based adsorbent. BACKGROUND

[0002] Automobiles are commonly used as a means of transportation, and are increasingly popular due to their excellent performance. As a result, the production of automobiles is increasing year by year. At the same time, the number of discarded automobiles is also gradually increasing. Tires are one of the parts of automobiles, and the recycling of discarded tires has become a problem that is widely concerned by society.

[0003] At present, the utilization of waste tires in China mainly has the following ways: 1, direct utilization of waste tires; 2, waste tire retreading; 3, waste tire heat energy utilization; 4, rubber regeneration; 5, waste tire rubber powder mixed asphalt for road paving materials; 6, waste tire pyrolysis for hydrocarbons and carbon residue. Among them, the pyrolysis recycling method is widely used due to its high resource recovery rate and low secondary pollution. In Chinese patent application CN106829955A, the above-mentioned pyrolysis recycling method is adopted, and the following technical features are disclosed: "A method for preparing activated carbon by using waste tire rubber in a vacuum microwave, comprising the following steps: removing the iron wire of the waste tire rubber, cutting it into small pieces and washing it, and then drying and treating; removing the oil substances on the rubber pieces; placing them in a microwave vacuum drying box for pyrolysis, collecting the solid substances; treating the collected solid substances with hydrogen peroxide and drying to obtain coke; placing the coke in a muffle furnace, heating the solid substances to 880-920 DEG C under a nitrogen atmosphere, keeping for 4-6 h, and then naturally cooling to room temperature; grinding the obtained sample into particles, sieving, and then immersing the sample particles in HNO3 solution, and then immersing them in NaOH solution to obtain activated carbon particles." Due to the high efficiency and low pollution of the above-mentioned treatment method, it has been widely used in the field of waste tire recycling technology. However, some problems have been exposed in the long-term use process. The above-mentioned prior art produces activated carbon particles through a series of pyrolysis processes, but does not effectively and accurately evaluate the adsorption performance of the activated carbon particles. This will result in that, although a series of treatment processes are adopted, it is impossible to qualitatively analyze each operation process, and thus it is impossible to accurately determine which operation process is the most effective. Without finding the most effective operation process, the staff still produces activated carbon particles according to different operation processes before, resulting in that the adsorption performance of the produced activated carbon particles is uneven, the production process cannot be unified and standardized, and thus the maximization of production efficiency cannot be realized, which is a problem to be solved. SUMMARY

[0004] In order to avoid and overcome the technical problems existing in the prior art, the application provides an evaluation method for CO2 adsorption performance of a waste tire-based adsorbent.

[0005] In order to achieve the above-mentioned purpose, the application provides the following technical scheme.

[0006] An evaluation method for CO2 adsorption performance of a waste tire-based adsorbent, comprising the following steps:

[0007] S1, decomposing and processing waste tires to produce a tire-based adsorbent;

[0008] S2, using a physical adsorption instrument to measure the corresponding CO2 adsorption amount of each group of tire-based adsorbents at different temperatures, and calculating the corresponding molar adsorption enthalpy change ΔH of each group of tire-based adsorbents at different temperatures 0 and the entropy change ΔS of the tire-based adsorbent under standard conditions 0 , saving the calculated data;

[0009] S3, importing the data in S2 into the definition formula of Gibbs free energy, and calculating the Gibbs free energy ΔG of each group of tire-based adsorbents when adsorbing CO2 under different temperature conditions 0 ;

[0010] S4, importing the data in S2 into the Clausius-Clapeyron equation, and calculating the equivalent adsorption heat Q of each group of tire-based adsorbents when adsorbing CO2 under different temperature conditions st ;

[0011] S5, importing the corresponding Gibbs free energy ΔG of each group of tire-based adsorbents 0 and the equivalent adsorption heat Q st into the calculation formula of the thermodynamic excellent index δ, and calculating the corresponding thermodynamic excellent index δ of each group of tire-based adsorbents; the thermodynamic excellent index δ and the adsorption performance of the tire-based adsorbent are positively correlated, and the tire-based adsorbent with the optimal adsorption performance is determined through the thermodynamic excellent index δ.

[0012] As a further scheme of the application, the calculation formula of the thermodynamic excellent index δ is as follows:

[0013]

[0014] Wherein, Q st represents the equivalent adsorption heat of the tire-based adsorbent, ΔQ st represents the equivalent adsorption heat change amount of the tire-based adsorbent; θ represents the possibility coefficient of the adsorbent engineering application.

[0015] CO2 adsorption amount of the tire-based adsorbent, CO2 adsorption amount of the tire-based adsorbent is a mmol / g, CO2 adsorption amount of the tire-based adsorbent is b mmol / g; the difference between the adsorption amount equal to a and the CO2 adsorption amount when the adsorption amount is equal to b;

[0016] AG 0 Gibbs free energy of the tire-based adsorbent;

[0017] Gibbs free energy AG of the tire-based adsorbent 0 when the CO2 adsorption amount is equal to 0;

[0018] f(T e ) indicates a function of the working environment temperature T e of the tire-based adsorbent when adsorbing CO2.

[0019]

[0020] The difference between the loading amount equal to a and the CO2 adsorption amount when the loading amount is equal to b in this formula. As a further aspect of the present application: the calculation formula of the Gibbs free energy AG 0 is as follows:

[0021] AG 0 = AH 0 -TAS 0

[0022]

[0023] The calculation formula of the equivalent adsorption heat Q st is as follows:

[0024]

[0025] wherein, AH 0 represents the molar adsorption enthalpy change of the tire-based adsorbent;

[0026] AS 0 represents the entropy change of the tire-based adsorbent under standard conditions;

[0027] R represents the ideal gas constant;

[0028] P represents the equilibrium pressure of the adsorbed CO2 gas;

[0029] ​CO2 adsorption amount of the tire-based adsorbent;

[0030] T represents the absolute temperature of the tire-based adsorbent.

[0031] As a further scheme of the present application, the step S1 is specifically as follows:

[0032] S11, selecting and cleaning waste tires, crushing the cleaned waste tires, removing steel wires, and sending the waste tires into a pyrolysis furnace for pyrolysis;

[0033] S12, collecting the waste tire coke produced by pyrolysis, and screening out waste tire coke of a target particle size through wet screening;

[0034] S13, grinding and mixing the screened waste tire coke with a first activating agent, then sending the mixture into a tubular furnace, and heating and activating the mixture by using a tubular furnace activation process;

[0035] S14, collecting the activated mixture, placing the mixture in an acid pickling agent to perform acid pickling and filtering by using an acid pickling process, and then adjusting the pH of the acid-pickled mixture to neutral;

[0036] S15, sending the mixture with the adjusted pH to the tubular furnace, and activating the mixture by using a second activating agent, to finally obtain a waste tire-based adsorbent.

[0037] As a further scheme of the present application, the first activating agent is KOH solid powder, and the mass ratio of the waste tire coke to the KOH solid powder is 1:3.

[0038] As a further scheme of the present application, the tubular furnace activation process is as follows: N2 with a flow rate of 300 mL / min is blown to the mixture, the activation time is 60 minutes, the activation temperature is 700°C, and the heating rate is 10°C / min.

[0039] As a further scheme of the present application, the second activating agent is CO2 gas, the CO2 gas is blown to the mixture through a gas inlet pipe, the gas flow rate of the CO2 is 100-300 mL / min, the activation time is 30-90 minutes, and the activation temperature is 700-900°C.

[0040] As a further scheme of the present application, the acid pickling agent is an HCl solution, and the acid pickling process is that the mixture is placed in 50 mL of 2M HCl solution for acid pickling for 5 hours.

[0041] As a further scheme of the present application, the wet screening uses a 140-mesh and 600-mesh screen, and the target particle size is 23-104 μm.

[0042] As a further scheme of the present application, the acid-pickled mixture is adjusted to neutral by using a NaOH solution.

[0043] Compared with the prior art, the present application has the beneficial effects that:

[0044] 1、 The present application uses waste tires as raw materials, realizing the resource recycling and utilization of solid waste. And as raw materials, it is low in price, widely sourced, and not affected by region and environment. Waste tires as raw materials use their own complexity to enhance the activation effect. It contains rich metal elements such as iron, sodium, calcium, etc., which will have a positive effect on the activation process.

[0045] 2、 The waste tire-based adsorbent of the present application is from the perspective of thermodynamic performance, compared with the engineering applicability and the temperature limit of the application, the larger the delta represents the better thermodynamic performance of activated carbon, and it has good renewable adsorption performance and spontaneous adsorption CO2 reaction at high temperature. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 It is the flowchart of the adsorption performance evaluation of the waste tire-based adsorbent of the present application.

[0047] Figure 2 It is the isotherm adsorption line graph of waste tire coke and waste tire-based adsorbent.

[0048] Figure 3 It is the pore volume pore size distribution graph of waste tire coke and waste tire-based adsorbent.

[0049] Figure 4 It is the thermodynamic excellent index comparison graph between waste tire adsorbents.

[0050] Figure 5 It is the surface morphology graph of waste tire-based adsorbent 2. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0052] The present application takes waste tires as a raw material, combines the characteristics of complex components of waste tires, and selectively selects an activation test. A waste tire-based adsorbent with low cost, high adsorption capacity, and good regeneration performance for adsorbing CO2 is prepared by adopting a two-step activation method of chemical activation and physical activation. Then, the highest limit of the waste tire-based adsorbent for adsorbing CO2 under standard conditions (1 atm, 0℃) is judged by the thermodynamic parameter Gibbs free energy. Meanwhile, the present application proposes a thermodynamic excellent index δ of the adsorbent for adsorbing CO2, which is a thermodynamic index for evaluating the adsorption capacity of the waste tire-based adsorbent for adsorbing CO2.

[0053] The production process of the waste tire-based adsorbent is as follows:

[0054] 1. The tire is washed, crushed and the steel wire is removed, and then sent into a pyrolysis furnace for pyrolysis, and the solid pyrolysis product, i.e. waste tire coke, is collected.

[0055] 2. The collected waste tire coke is sieved by wet screening to obtain waste tire coke within the range of 140-600 meshes, and at this time, the target particle size of the waste tire coke is between 23-104 μm.

[0056] 3. The sieved waste tire coke is ground and mixed with the first activator according to a certain mass ratio. The first activator can be KOH solid powder, and the mass ratio of the waste tire coke to KOH is 1:3.

[0057] The mixture is sent into a tubular furnace and activated by a tubular furnace activation process. The tubular furnace activation process is as follows: N2 provided by an N2 gas supply machine is blown to the mixture at a flow rate of 300 mL / min, the continuous activation time is 60 minutes, the activation temperature in the tubular furnace is 700℃, and the temperature rising rate is 10℃ / min, and the temperature is finally raised to 760℃.

[0058] 4. After the tubular furnace activation is completed, the mixture is placed in a 2M HCl solution for acid washing for 5 hours. Then the mixture is filtered out, and deionized water is used to wash the mixture until the acid substances on the surface of the mixture are washed clean, and finally the washed liquid is neutral, so that the mixture is washed clean. The washed mixture is dried and collected.

[0059] 5. The collected mixture is again placed in a tubular furnace and activated again by a second activator. This activation adopts a CO2 activation process, i.e. the second activator is CO2 gas. The CO2 gas is blown to the mixture by a CO2 generator through a gas inlet pipe for 30-90 minutes; and the gas flow rate of CO2 is 100-300 mL / min, and the activation temperature is 700-900℃. After the CO2 activation process, the tire-based adsorbent is prepared.

[0060] Once the tire-based adsorbent is prepared, its adsorption performance can be tested.

[0061] First, a Micromeritics ASAP2020 physical adsorption instrument was used to measure the CO2 adsorption capacity of each group of tire-based adsorbents at different temperatures, and the data were saved.

[0062] Next, the saved data was imported into the definition of Gibbs free energy to calculate the Gibbs free energy ΔG of each group of tire-based adsorbents when adsorbing CO2 under different temperature conditions. 0 .

[0063] The saved data was then imported back into the Clausius-Clapeyron equation to calculate the isotropic heat of adsorption Q of each group of tire-based adsorbents when adsorbing CO2 under different temperature conditions. st .

[0064] Finally, the Gibbs free energy ΔG corresponding to each group of tire-based adsorbents was calculated. 0 and equal adsorption heat Q st The thermodynamic excellence index δ is imported into the calculation formula to calculate the thermodynamic excellence index δ corresponding to each group of tire-based adsorbents. The thermodynamic excellence index δ is positively correlated with the adsorption performance of the tire-based adsorbent. The tire-based adsorbent with the best adsorption performance is determined by the thermodynamic excellence index δ.

[0065] Gibbs free energy ΔG 0 The calculation formula is as follows:

[0066] ΔG 0 =ΔH 0 -TΔS 0

[0067] Equal adsorption heat Q st The calculation formula is as follows:

[0068]

[0069] The formula for calculating the thermodynamic excellence index δ is as follows:

[0070]

[0071] Wherein, δ is the thermodynamic excellence index of the tire-based adsorbent;

[0072] ΔH 0 The molar adsorption enthalpy change of the tire-based adsorbent is expressed in kJ / mol.

[0073] ΔS 0 This represents the entropy change of the tire-based adsorbent under standard conditions, expressed in kJ / mol.

[0074] R represents the ideal gas constant, with a value of 8.314 J·mol⁻¹. -1 ·K -1 ;

[0075] P represents the equilibrium pressure of the adsorbed CO2 gas, in atm;

[0076] The CO2 adsorption capacity of the tire-based adsorbent is expressed in mmol / g.

[0077] T represents the absolute temperature of the tire-based adsorbent, in K.

[0078] Q st This represents the heat of adsorption of the tire-based adsorbent.

[0079] θ represents the probability coefficient of the adsorbent's engineering application, which is proportional to the probability of engineering application, and θ∈[1,2].

[0080] The values ​​represent the CO2 adsorption capacity of the tire-based adsorbent, where a represents the minimum CO2 adsorption capacity of the tire-based adsorbent and b represents the maximum CO2 adsorption capacity of the tire-based adsorbent.

[0081] ΔG 0 This represents the Gibbs free energy of the tire-based adsorbent.

[0082] The Gibbs free energy ΔG represents the energy of the tire-based adsorbent. 0 The temperature at which the temperature equals 0;

[0083] f(T e T represents the ambient temperature function when the tire-based adsorbent adsorbs CO2. e The operating temperature for tire-based adsorbents to adsorb CO2. When T e At ≤90℃, f(T) e ) = 1, when T e At >90℃, f(T) e =2.

[0084] Example 1:

[0085] First, waste tires are cleaned, crushed, and the steel wire is recycled. Then, they are fed into a pyrolysis furnace for pyrolysis, and the solid products from the pyrolysis are collected. The waste tire coke is wet-sieved, passing through a 140-mesh sieve but not a 600-mesh sieve, collecting products of the target particle size. The waste tire coke is then ground and mixed with KOH at a mass ratio of 1:3. The ground mixture is then activated in a tube furnace with the following parameters: heating rate 10℃ / min, activation temperature 700℃, and activation time 60min. After activation is complete and the temperature drops to room temperature, the mixture is removed. The mixture is acid-washed with 50mL of 2M HCl solution for 5 hours. Then, it is rinsed with deionized water and filtered multiple times until the pH of the filtrate is neutral. The filtered product is dried in a drying oven at 105℃. The product is collected and then sent to a tube furnace for CO2 activation with a CO2 flow rate of 100mL / min, an activation temperature of 700℃, an activation time of 30min, and a heating rate of 10℃ / min. After the process is completed and the temperature drops to room temperature, the product is collected to obtain waste tire-based adsorbent 1.

[0086] Example 2:

[0087] First, waste tires are cleaned, crushed, and the steel wire is recycled. Then, they are fed into a pyrolysis furnace for pyrolysis, and the solid products from the pyrolysis are collected. The waste tire coke is wet-sieved, passing through a 140-mesh sieve but not a 600-mesh sieve, collecting products of the target particle size. The waste tire coke is then ground and mixed with KOH at a mass ratio of 1:3. The ground mixture is then activated in a tube furnace with the following parameters: heating rate 10℃ / min, activation temperature 700℃, and activation time 60min. After activation is complete and the temperature drops to room temperature, the mixture is removed. The mixture is acid-washed with 50mL of 2M HCl solution for 5 hours. Then, it is rinsed with deionized water and filtered multiple times until the pH of the filtrate is neutral. The filtered product is dried in a drying oven at 105℃. The product is collected and then sent to a tube furnace for CO2 activation at a CO2 flow rate of 100mL / min, an activation temperature of 750℃, an activation time of 60min, and a heating rate of 10℃ / min. After the process is completed and the temperature drops to room temperature, the product is collected to obtain waste tire-based adsorbent 2.

[0088] Example 3:

[0089] First, waste tires are cleaned, crushed, and the steel wire is recycled. Then, they are fed into a pyrolysis furnace for pyrolysis, and the solid products from the pyrolysis are collected. The waste tire coke is wet-sieved, passing through a 140-mesh sieve but not a 600-mesh sieve, collecting products of the target particle size. The waste tire coke is then ground and mixed with KOH at a mass ratio of 1:3. The ground mixture is then activated in a tube furnace with the following parameters: heating rate 10℃ / min, activation temperature 700℃, and activation time 60min. After activation is complete and the temperature drops to room temperature, the mixture is removed. The mixture is acid-washed with 50mL of 2M HCl solution for 5 hours. Then, it is rinsed with deionized water and filtered multiple times until the pH of the filtrate is neutral. The filtered product is dried in a drying oven at 105℃. The product is collected and then sent to a tube furnace for CO2 activation with a CO2 flow rate of 100mL / min, an activation temperature of 800℃, an activation time of 90min, and a heating rate of 10℃ / min. After the process is completed and the temperature drops to room temperature, collect the product to obtain waste tire-based adsorbent 3.

[0090] Example 4:

[0091] First, waste tires are cleaned, crushed, and the steel wire is recycled. Then, they are fed into a pyrolysis furnace for pyrolysis, and the solid products from the pyrolysis are collected. The waste tire coke is wet-sieved, passing through a 140-mesh sieve but not a 600-mesh sieve, collecting products of the target particle size. The waste tire coke is then ground and mixed with KOH at a mass ratio of 1:3. The ground mixture is then activated in a tube furnace with the following parameters: heating rate 10℃ / min, activation temperature 700℃, and activation time 60min. After activation is complete and the temperature drops to room temperature, the mixture is removed. The mixture is acid-washed with 50mL of 2M HCl solution for 5 hours. Then, it is rinsed with deionized water and filtered multiple times until the pH of the filtrate is neutral. The filtered product is dried in a drying oven at 105℃. The product is collected and then sent to a tube furnace for CO2 activation at a CO2 flow rate of 200mL / min, an activation temperature of 700℃, an activation time of 60min, and a heating rate of 10℃ / min. After the process is completed and the temperature drops to room temperature, collect the product to obtain waste tire-based adsorbent 4.

[0092] Example 5:

[0093] First, waste tires are cleaned, crushed, and the steel wire is recycled. Then, they are fed into a pyrolysis furnace for pyrolysis, and the solid products from the pyrolysis are collected. The waste tire coke is wet-sieved, passing through a 140-mesh sieve but not a 600-mesh sieve, collecting products of the target particle size. The waste tire coke is then ground and mixed with KOH at a mass ratio of 1:3. The ground mixture is then activated in a tube furnace with the following parameters: heating rate 10℃ / min, activation temperature 700℃, and activation time 60min. After activation is complete and the temperature drops to room temperature, the mixture is removed. The mixture is acid-washed with 50mL of 2M HCl solution for 5 hours. Then, it is rinsed with deionized water and filtered multiple times until the pH of the filtrate is neutral. The filtered product is dried in a drying oven at 105℃. The product is collected and then sent to a tube furnace for CO2 activation at a CO2 flow rate of 200mL / min, an activation temperature of 750℃, an activation time of 90min, and a heating rate of 10℃ / min. After the process is completed and the temperature drops to room temperature, collect the product to obtain waste tire-based adsorbent 5.

[0094] Example 6:

[0095] First, waste tires are cleaned, crushed, and the steel wire is recycled. Then, they are fed into a pyrolysis furnace for pyrolysis, and the solid products from the pyrolysis are collected. The waste tire coke is wet-sieved, passing through a 140-mesh sieve but not a 600-mesh sieve, collecting products of the target particle size. The waste tire coke is then ground and mixed with KOH at a mass ratio of 1:3. The ground mixture is then activated in a tube furnace with the following parameters: heating rate 10℃ / min, activation temperature 700℃, and activation time 60min. After activation is complete and the temperature drops to room temperature, the mixture is removed. The mixture is acid-washed with 50mL of 2M HCl solution for 5 hours. Then, it is rinsed with deionized water and filtered multiple times until the pH of the filtrate is neutral. The filtered product is dried in a drying oven at 105℃. The product is collected and then sent to a tube furnace for CO2 activation with a CO2 flow rate of 200mL / min, an activation temperature of 800℃, an activation time of 30min, and a heating rate of 10℃ / min. After the process is completed and the temperature drops to room temperature, collect the product to obtain waste tire-based adsorbent 6.

[0096] Example 7:

[0097] First, waste tires are cleaned, crushed, and the steel wire is recycled. Then, they are fed into a pyrolysis furnace for pyrolysis, and the solid products from the pyrolysis are collected. The waste tire coke is wet-sieved, passing through a 140-mesh sieve but not a 600-mesh sieve, collecting products of the target particle size. The waste tire coke is then ground and mixed with KOH at a mass ratio of 1:3. The ground mixture is then activated in a tube furnace with the following parameters: heating rate 10℃ / min, activation temperature 700℃, and activation time 60min. After activation is complete and the temperature drops to room temperature, the mixture is removed. The mixture is acid-washed with 50mL of 2M HCl solution for 5 hours. Then, it is rinsed with deionized water and filtered multiple times until the pH of the filtrate is neutral. The filtered product is dried in a drying oven at 105℃. The product is collected and then sent to a tube furnace for CO2 activation at a CO2 flow rate of 300mL / min, an activation temperature of 700℃, an activation time of 90min, and a heating rate of 10℃ / min. After the process is completed and the temperature drops to room temperature, collect the product to obtain waste tire-based adsorbent 7.

[0098] Example 8:

[0099] First, waste tires are cleaned, crushed, and the steel wire is recycled. Then, they are fed into a pyrolysis furnace for pyrolysis, and the solid products from the pyrolysis are collected. The waste tire coke is wet-sieved, passing through a 140-mesh sieve but not a 600-mesh sieve, collecting products of the target particle size. The waste tire coke is then ground and mixed with KOH at a mass ratio of 1:3. The ground mixture is then activated in a tube furnace with the following parameters: heating rate 10℃ / min, activation temperature 700℃, and activation time 60min. After activation is complete and the temperature drops to room temperature, the mixture is removed. The mixture is acid-washed with 50mL of 2M HCl solution for 5 hours. Then, it is rinsed with deionized water and filtered multiple times until the pH of the filtrate is neutral. The filtered product is dried in a drying oven at 105℃. The product is collected and then sent to a tube furnace for CO2 activation with a CO2 flow rate of 300mL / min, an activation temperature of 750℃, an activation time of 30min, and a heating rate of 10℃ / min. After the process is completed and the temperature drops to room temperature, collect the product to obtain waste tire-based adsorbent 8.

[0100] Example 9:

[0101] First, waste tires are cleaned, crushed, and the steel wire is recycled. Then, they are fed into a pyrolysis furnace for pyrolysis, and the solid products from the pyrolysis are collected. The waste tire coke is wet-sieved, passing through a 140-mesh sieve but not a 600-mesh sieve, collecting products of the target particle size. The waste tire coke is then ground and mixed with KOH at a mass ratio of 1:3. The ground mixture is then activated in a tube furnace with the following parameters: heating rate 10℃ / min, activation temperature 700℃, and activation time 60min. After activation is complete and the temperature has cooled to room temperature, the mixture is removed. The mixture is acid-washed with 50mL of 2M HCl solution for 5 hours. Then, it is rinsed with deionized water and filtered multiple times until the pH of the filtrate is neutral. The filtered product is dried in a drying oven at 105℃. The product is collected and then sent to a tube furnace for CO2 activation at a CO2 flow rate of 300mL / min, an activation temperature of 800℃, an activation time of 60min, and a heating rate of 10℃ / min. After the process is completed and the temperature drops to room temperature, collect the product to obtain waste tire-based adsorbent 9.

[0102] The waste tire-based adsorbents 1-9 obtained in Examples 1-9 and waste tire coke were analyzed using a gas adsorption analyzer to determine the N2 adsorption-desorption isotherms. The specific surface area and pore size distribution were calculated using the BET method and DFT model, respectively. The pore structure characteristics data are summarized in Table 1.

[0103] Table 1. Pore physical structure data of waste tire coke and waste tire-based adsorbents 1-9

[0104]

[0105] The N2 adsorption / desorption isotherms are shown below. Figure 1 Aperture distribution diagram is shown below. Figure 2 .from Figure 2 As can be seen, the waste tire-based adsorbent has a rich microporous and mesoporous structure, which can enhance the storage and transport performance of CO2 molecules.

[0106] CO2 adsorption tests were conducted on the waste tire-based adsorbents 1-9 and waste tire coke obtained in Examples 1-9 using a physical adsorption apparatus. The samples were degassed for 2 hours at 200°C under vacuum before testing. The waste tire coke was tested at 30°C; the waste tire-based adsorbents 1-9 were also tested for CO2 adsorption at 30°C; additionally, waste tire-based adsorbents 2, 4, 6, and 8 were tested for CO2 adsorption at 40, 50, and 70°C, respectively. The adsorption results are summarized in Tables 2 and 3.

[0107] Table 2. Results of CO2 adsorption by waste tire coke and waste tire-based adsorbent at 30℃

[0108]

[0109] Table 3. CO2 adsorption capacity of waste tire adsorbents 2, 4, 6, and 8 at different temperatures.

[0110]

[0111] From Tables 1, 2, and 3, we can conclude that:

[0112] The total specific surface area of ​​the waste tire-based adsorbent is 592.129-762.172 m2 / g.

[0113] The average pore size of the waste tire-based adsorbent is 7.362-7.718 nm.

[0114] The total pore volume of the waste tire-based adsorbent is 0.57391-0.76136 cm3 / g.

[0115] When the specific surface area of ​​the waste tire-based adsorbent is 762.172 m² / g, the CO₂ adsorption capacity is 0.83-1.42 mmol / g, and the CO₂ loading is 0 and 0.8 mmol / g, the difference in heat of adsorption is 10.49 kJ / mol. When the Gibbs free energy is 0,

[0116] The heat of adsorption of the waste tire-based adsorbent is 10.49 kJ / mol. f(T e Given that ) = 1, and considering industrial applicability, θ is chosen as 1.5, at which point the thermodynamic excellence index δ is 106.25.

[0117] The adsorption isotherm Qst of waste tire-based adsorbent 2, waste tire-based adsorbent 4, waste tire-based adsorbent 6 and waste tire-based adsorbent 8 was calculated using adsorption data at different temperatures. The results are shown in Table 4. The calculation results prove that they have excellent regenerability.

[0118] Table 4. Calculation results of the thermodynamic excellence index of waste tire adsorbents 2, 4, 6, and 8.

[0119]

[0120] We calculated the thermodynamic excellence index δ for CO2 adsorption of tire-based adsorbent 2, waste tire-based adsorbent 4, waste tire-based adsorbent 6, and waste tire-based adsorbent 8. Through the above characterization and calculations, we know that the isochoric adsorption heat difference values ​​are shown in Table 4 when the CO2 loading is between 0 and 0.8 mmol / g; while when the Gibbs free energy is equal to 0, They are also summarized in Table 4; taking into account their industrial applicability and the ambient temperature for CO2 adsorption, f(T) e When ) = 1 and θ = 1.5, the thermodynamic excellence index δ results are shown in Table 4, and the results are compared in [the table below].Figure 3 The results showed that waste tire-based adsorbent 2 had a higher thermodynamic performance index.

[0121] A field emission scanning electron microscope (FE-SEM, CA-241) was used to test the surface morphology of waste tire-based adsorbent 2. The test results are shown in [Figure 1]. Figure 4 It can be seen from Figure 4 As observed, the waste tire-based adsorbent has a rich microporous and mesoporous structure, and the whole is composed of multiple carbon cluster spheres connected together.

[0122] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for evaluating the CO2 adsorption performance of a waste tire-based adsorbent, characterized in that, Includes the following steps: S1. Use a physical adsorption apparatus to measure the CO2 adsorption capacity of each group of tire-based adsorbents at different temperatures, and calculate the molar adsorption enthalpy change Δ of each group of tire-based adsorbents at these different temperatures. H 0 Entropy change ΔS of tire-based adsorbent under standard conditions 0 Save the calculated data; S2. Import the data from S1 into the definition of Gibbs free energy to calculate the Gibbs free energy Δ for each group of tire-based adsorbents adsorbing CO2 under different temperature conditions. G 0 ; S3. Import the data from S1 into the Clausius-Clapeyron equation to calculate the isotropic heat of adsorption of CO2 by each group of tire-based adsorbents under the different temperature conditions. Q st ; S4. The Gibbs free energy Δ corresponding to each group of tire-based adsorbents G 0 and equal amount of adsorption heat Q st Importing the thermodynamic excellence index δ The calculation formula is used to calculate the thermodynamic excellence index of each group of tire-based adsorbents. δ Thermodynamic Excellence Index δ The adsorption performance of tire-based adsorbents is positively correlated with the selection of thermodynamic excellence index. δ The largest tire-based adsorbent is considered the tire-based adsorbent with the best adsorption performance; the thermodynamic excellence index... δ The calculation formula is as follows: in, Q st Δ represents the heat of adsorption of the tire-based adsorbent. Q st This represents the change in heat of adsorption of tire-based adsorbents at equal amounts; θ Indicates the probability coefficient of the adsorbent's engineering application; This indicates the CO2 adsorption capacity of the tire-based adsorbent. = a This indicates that the CO2 adsorption capacity of the tire-based adsorbent is... a mmol / g = b This indicates that the CO2 adsorption capacity of the tire-based adsorbent is... b mmol / g; This indicates that the adsorption capacity of the waste tire-based adsorbent is equal to the difference between the CO2 adsorption capacity when a is equal to b. Δ G 0 This represents the Gibbs free energy of the tire-based adsorbent. The Gibbs free energy Δ of the tire-based adsorbent G 0 The temperature at which =0; f ( T e The expression represents the working environment temperature function when the tire-based adsorbent adsorbs CO2. T e The operating temperature for the tire-based adsorbent to adsorb CO2; the Gibbs free energy Δ G 0 The calculation formula is as follows: The equal amount of adsorption heat Q st The calculation formula is as follows: Where, Δ H 0 Indicates the molar adsorption enthalpy change of the tire-based adsorbent; ΔS 0 This represents the entropy change of the tire-based adsorbent under standard conditions; R Represents the ideal gas constant; P This indicates the equilibrium pressure of the adsorbed CO2 gas. This indicates the amount of CO2 adsorbed by the tire-based adsorbent; T This indicates the absolute temperature of the tire-based adsorbent.

2. The method for evaluating the CO2 adsorption performance of a waste tire-based adsorbent according to claim 1, characterized in that, The specific steps of S1 are as follows: S11. Select waste tires and clean them. Crush the cleaned waste tires, remove the steel wires, and send them into the pyrolysis furnace for pyrolysis. S12. Collect the waste tire coke produced by pyrolysis and screen the waste tire coke to the target particle size through wet screening. S13. Grind and mix the screened waste tire coke with the first activator, then send the mixture to a tubular furnace and heat and activate it using the tubular furnace activation process. S14. Collect the activated mixture, place the mixture in the pickling agent and pickle it using the pickling process, then filter it. Next, adjust the pH of the pickled mixture to neutral. S15. The mixture after adjusting the pH to neutral is sent to a tubular furnace and activated with a second activator to finally obtain the waste tire-based adsorbent.

3. The method for evaluating the CO2 adsorption performance of a waste tire-based adsorbent according to claim 2, characterized in that, The first activator is KOH solid powder, and the mass ratio of waste tire coke to KOH solid powder is 1:

3.

4. The method for evaluating the CO2 adsorption performance of a waste tire-based adsorbent according to claim 3, characterized in that, The tube furnace activation process is as follows: N2 is blown onto the mixture at a flow rate of 300 mL / min, the activation time is 60 minutes, the activation temperature is 700℃, and the heating rate is 10℃ / min.

5. The method for evaluating the CO2 adsorption performance of a waste tire-based adsorbent according to claim 4, characterized in that, The second activator is CO2 gas, which is blown into the mixture through an inlet pipe. The CO2 gas flow rate is 100-300 mL / min, the activation time is 30-90 minutes, and the activation temperature is 700-900℃.

6. The method for evaluating the CO2 adsorption performance of a waste tire-based adsorbent according to claim 5, characterized in that, The pickling agent is an HCl solution, and the pickling process is as follows: the mixture is placed in 50 mL of 2M HCl solution and pickled for 5 hours.

7. The method for evaluating the CO2 adsorption performance of a waste tire-based adsorbent according to claim 6, characterized in that, The wet screening used 140-mesh and 600-mesh sieves, with a target particle size of 23-104 µm.

8. The method for evaluating the CO2 adsorption performance of a waste tire-based adsorbent according to claim 2, characterized in that, The solution of the acid-washed mixture was prepared to be neutral using NaOH solution.

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