Method for preparing carbon molecular sieve with adjustable pore by binary activation of heavy oil and application thereof

Abstract

The application discloses a method for preparing a carbon molecular sieve with adjustable pores from heavy oil by binary activation and application thereof, and belongs to the technical field of biomass resource utilization and water treatment. The method comprises the following steps: (1) mixing heavy oil and a binary activation agent, and forming a carbon-containing precursor mixture after standing; wherein the binary activation agent is calcium citrate and potassium oxalate; (2) pyrolyzing and activating the carbon-containing precursor mixture under an inert atmosphere, and obtaining bio-activated carbon after cooling; and (3) washing and drying the bio-activated carbon to obtain a carbon molecular sieve. The application has the advantages of green environmental protection, convenient process and efficient production. The carbon molecular sieve has developed pore structure, concentrated pore size distribution and good adsorption characteristics, has a wide application prospect in water treatment, and realizes comprehensive disposal of resource utilization of two kinds of pollutants, namely, waste heavy oil and dye wastewater.

Description

Technical Field

[0001] This invention relates to the fields of biomass resource utilization and water treatment technology, and to a method for preparing tunable-pore carbon molecular sieves by binary activation of heavy oil and its application. Background Technology

[0002] Industrial wastewater containing complex organic macromolecular dyes, especially typical pollutants such as methyl orange, Congo red, and methylene blue (MB), poses a serious threat to aquatic environments. MB has received particular attention due to its unique physicochemical properties; this substance not only exhibits significant environmental persistence and bioaccumulation but can also cause multiple toxic effects on organisms through the food chain. Studies have confirmed that MB exposure can trigger oxidative stress in aquatic organisms, leading to DNA damage and reproductive dysfunction. More alarmingly, MB pollution has spread from aquatic environments to soil systems, forming a complex pollution pattern that poses potential risks to farmland ecological security and groundwater quality. Therefore, the effective purification and treatment of dye wastewater has attracted widespread attention.

[0003] In the field of water treatment technology, porous activated carbon materials are widely used in wastewater treatment and purification due to their low cost, high specific surface area, large pore volume, renewability, and excellent adsorption properties. The most commonly used activating agents in traditional activated carbon material production processes are KOH and K₂CO₃.

[0004] For example, the document (Wang K, Xu S. Preparation of High Specific Surface Area Activated Carbon from Petroleum Coke by KOH Activation in a Rotary Kiln [J]. Processes, 2024, 12(2). DOI: 10.3390 / pr12020241.) developed a new method for preparing activated carbon (AC) from petroleum coke (PC) by KOH activation using a rotary kiln equipped with steel balls. It uses molten KOH to cause the reaction mixture to expand at lower activation temperatures, while molten K2O causes particle agglomeration at higher temperatures. Steel balls alleviate expansion and agglomeration by promoting heat and mass transfer in the reactor, promoting the development of the pore structure of AC. Introduce CO2 during the activation process, further reduce the agglomeration of particles by converting K2O to thermosetting K2CO3, and form more mesopores in AC. In addition, the document (Wu C, Liu J, Wang Y, et al. A clean method for controlling pore structure development in potassium activation systems to improve CO2 adsorption properties of biochar [J]. Science of the Total Environment, 2024, 954. DOI: 10.1016 / j.scitotenv.2024.176429.) uses a KCl-assisted activation process to prepare CO2 adsorbents with high specific surface area and excellent adsorption performance using three activators (KOH, KHCO3, K2CO3). However, these methods are corrosive, not only causing serious corrosion to equipment, but also causing heavy metal pollution risks. From the analysis of the microstructure of carbon materials, the activated carbon produced by these methods has a developed pore structure and a large pore volume, but the pore size structure is relatively dispersed, and most of the pores do not effectively play a role, thereby limiting the overall performance of the activated carbon. Based on this, the development of binary activation technology based on the concept of green chemistry to construct a hierarchical pore system through a synergistic physical-chemical activation mechanism to realize precise regulation of pore size distribution has become a key research direction to break through the performance bottleneck of carbon molecular sieve materials, which has important engineering application value for promoting the development of environmental functional material science.

[0005] Heavy oil is a non-water-soluble liquid, which is mainly generated by macromolecular deposition in the process of biomass pyrolysis or gasification. Heavy oil has the characteristics of complex composition, high carbon content, low ash content, high viscosity, good thermal plasticity and easy polymerization, which makes it difficult to be directly purified into high value-added chemicals and liquid fuels by purification methods such as distillation and extraction. If a new processing and utilization process is developed, the waste heavy oil is converted into carbon-based molecular sieve adsorbent material with highly concentrated pore structure by thermochemical method, and as high-performance adsorbent material, it can remove pollutants by water treatment, which not only realizes waste recycling, but also effectively solves the problem of direct utilization of heavy oil, and provides a new way for environmental pollution control. SUMMARY

[0006] In view of the above defects of the prior art, in the first aspect of the present application, a process convenient and efficient heavy oil binary activation method for preparing carbon molecular sieve with adjustable pore is provided, comprising the following steps:

[0007] (1) mixing heavy oil and binary activator, and forming carbon-containing precursor mixture after standing; wherein the binary activator is calcium citrate and potassium oxalate;

[0008] (2) pyrolysis activation of the carbon-containing precursor mixture under inert atmosphere, and obtaining bioactive carbon after cooling after pyrolysis is completed;

[0009] (3) washing and drying the bioactive carbon to obtain carbon molecular sieve.

[0010] Preferably, in step (1), the mass ratio of heavy oil, calcium citrate and potassium oxalate is 2:1:0.25-2.

[0011] The component ratio of heavy oil and binary activator should be controlled within the preferred range of the present application. If the proportion of calcium citrate is too low, the ordered arrangement process of carbon microcrystal will be weakened, which is not conducive to the formation of carbon with high graphitization degree, and will weaken the subsequent K + or CO2 molecule reaction on the carbon skeleton. If the proportion of calcium citrate is too high, CaO template will be generated by pyrolysis, more space-occupying pore-forming reactions will occur, and the mesoporous structure of the produced active carbon will be greatly increased, which is not conducive to the formation of active carbon adsorbent material with highly concentrated pore size distribution. If the overall amount of binary activator continues to increase, it is not conducive to environmental / economic sustainability. Therefore, the binary activator with appropriate mass mixing ratio can benefit from the synergistic effect between the binary activators, so as to form active carbon with molecular sieve characteristics and highly concentrated pore size distribution.

[0012] Preferably, in step (1), the mixing time is 5-30 min, and the standing time is 5-30 min.

[0013] Mixing and standing can help ensure that the components are mixed evenly.

[0014] Preferably, in the step (2), the initial temperature of pyrolysis is room temperature, the heating rate is 5-10 ℃ / min, the pyrolysis temperature is 600-800 ℃, and the holding time is 10-60 min.

[0015] Preferably, in the step (2), the type of gas in the inert atmosphere includes at least one of nitrogen, argon and helium; and the gas flow rate is 50-100 mL / min.

[0016] The person skilled in the art can select a suitable pyrolysis device based on actual conditions, such as a pyrolysis furnace. Common pyrolysis furnaces include fluidized bed reactors and fixed bed reactors, and the fixed bed reactor has certain advantages compared with the fluidized bed reactor, i.e. the activator can fully contact with the heavy oil to react.

[0017] Preferably, in the step (3), the bioactive carbon is washed with dilute acid and water, and then dried at 100-150 ℃ to obtain the carbon molecular sieve.

[0018] Further preferably, the type of dilute acid includes at least one of hydrochloric acid, nitric acid and sulfuric acid; and the concentration of the dilute acid is 0.1-1 mol / L.

[0019] In the second aspect of the present application, a carbon molecular sieve with developed pore structure and concentrated pore size distribution is provided, which is prepared by the method provided in the first aspect of the present application.

[0020] In the third aspect of the present application, the carbon molecular sieve provided in the second aspect of the present application is used as an adsorption material in water treatment.

[0021] Preferably, the carbon molecular sieve is used as an adsorption material to remove dye pollutants in wastewater.

[0022] Based on the above technical solutions, the design concept and principle of the present application are as follows:

[0023] This invention proposes a method for preparing activated carbon materials by thermally polymerizing heavy components in heavy oil through a simple thermochemical conversion (pyrolysis activation). In this process, the complex composition, high carbon content, low ash content, good thermoplasticity, and ease of polymerization of heavy oil are utilized to overcome its drawbacks of high viscosity, poor flowability, and difficulty in direct utilization. This allows for the efficient conversion of waste heavy oil for use in water purification. Simultaneously, the synergistic coupling effect between the binary green activators is fully utilized to promote the efficient activation reaction. The biomass-derived heavy oil used is widely available, has a high carbon content and high viscosity, and is in a semi-liquid state, perfectly dissolving the binary organic salt activators. This allows the large molecular components in the heavy oil to fully contact the activator molecules, facilitating the efficient functioning of the activators and promoting the efficient activation reaction.

[0024] Traditional methods for selecting activators in thermochemical conversion processes often involve inorganic salts such as KOH and K₂CO₃, which are highly corrosive and not environmentally friendly. This invention selects relatively mild organic salts such as calcium citrate and potassium oxalate as activators, which are not only environmentally friendly but also produce carbon materials with molecular sieve properties.

[0025] The pyrolysis activation process of heavy oil is relatively complex. During pyrolysis, calcium citrate activator generates metal oxide (CaO) and releases CO2 gas. CaO acts as a template agent, guiding the ordered arrangement of carbon microcrystals to form highly graphitized carbon materials, while the released CO2 contributes to the formation of microporous carbon structures. Furthermore, during activation, calcium citrate activator can dissociate calcium ions (CaO) in solution. 2+ ), Ca 2+ Because its high charge density can promote cross-linking between molecules, it connects the macromolecules of heavy components in heavy oil to form macromolecular backbone bridges, which is conducive to the polymerization reaction of macromolecules.

[0026] Potassium oxalate activator forms potassium oxide and releases CO2 during pyrolysis. At high temperatures, the potassium oxide reacts with small carbon molecules in the heavier components through a gasification reaction (C + K2O → CO↑ + 2K), while the generated CO2 can etch the carbon framework (CO2 + C → 2CO), contributing to the formation of microporous carbon. Furthermore, during activation, potassium oxalate activator dissociates into potassium ions (K+) in solution. + ), K + It can promote the generation of free radicals and accelerate chain cleavage reactions. K + The presence of [certain substances] promotes chain pyrolysis reactions, forming more aromatic free radicals, and this process contributes to the formation of Ca[substances]. 2+The free radicals generated by the cleavage are captured, and the synergistic effect between the two promotes the polycondensation reaction to form polycyclic aromatic hydrocarbons. In addition, the synergistic effect between the binary activators helps to dynamically adjust the pore structure.

[0027] Therefore, the method is advantageous in forming carbon molecular sieves with uniform pore structures and concentrated pore size distribution, and greatly improves the quality of carbon products. When the carbon molecular sieves are applied to efficient water treatment, the dye wastewater is treated and purified simultaneously while the waste heavy oil is effectively treated, so that the comprehensive disposal of the two pollutants, i.e., waste heavy oil and dye wastewater, is realized.

[0028] Compared with the prior art, the method has the following advantages and beneficial effects:

[0029] The method for preparing carbon molecular sieves with adjustable pore channels from heavy oil by binary activation has the advantages of green environmental protection, convenient process and high production efficiency.

[0030] The carbon molecular sieves provided by the application have developed pore channel structures and concentrated pore size distribution, and have good adsorption properties.

[0031] The application of the carbon molecular sieves as adsorption materials in water treatment has broad application prospects. DETAILED DESCRIPTION

[0032] Figure 1 The flowchart of the method for preparing carbon molecular sieves with adjustable pore channels from heavy oil by binary activation and the application thereof;

[0033] Figure 2 The micro-morphology comparison chart of the carbon molecular sieve adsorbents prepared in the examples; wherein, (a)-(f) correspond to the observation results of HBAC-0 to HBAC-5, respectively;

[0034] Figure 3 The X-ray diffraction comparison chart of the carbon molecular sieve adsorbents prepared in the examples;

[0035] Figure 4 The physical parameter characterization results of the carbon molecular sieve adsorbents prepared in the examples; wherein, (a) is the nitrogen adsorption and desorption curve of each carbon molecular sieve adsorbent, (b) is the total pore specific surface area of each carbon molecular sieve adsorbent, (c) is the micropore specific surface area of each carbon molecular sieve adsorbent, and (d)-(i) correspond to the pore size distribution curve comparison charts of HBAC-0 to HBAC-5, respectively;

[0036] Figure 5 The adsorption rate and removal rate comparison chart of the adsorbent samples under different experimental conditions in the application of the application;

[0037] Figure 6It is a comparison chart of the influence of the adsorbent sample on the adsorption of MB under different experimental conditions in the application of the application; wherein, (a) is a graph of the relationship between the initial concentration of MB and the adsorption amount, (b) is a graph of the relationship between the adsorption time and the adsorption amount. DETAILED DESCRIPTION

[0038] The application will be further described in the following examples, but the application is not limited to the scope of the examples. The experimental methods in the following examples are not specified, which are selected according to the conventional methods and conditions, or according to the product instructions.

[0039] In the following examples:

[0040] The commercial source of the commercial activated carbon is Huazhen Activated Carbon Co., Ltd., and the product type is coconut shell water purification carbon.

[0041] The biomass heavy oil is obtained by condensing the lower viscous liquid phase of the bio-oil after pyrolysis of pine wood powder under an inert atmosphere (nitrogen atmosphere, purity 99.999%) and at a temperature of 500 ℃ for 1 h.

[0042] Example 1

[0043] The method for preparing a carbon molecular sieve with adjustable pore channel by binary activation of heavy oil is as follows:

[0044] (1) The heavy component obtained by pyrolysis of pine wood is selected as the heavy oil sample, and the heavy oil, calcium citrate and potassium oxalate activator are weighed according to the mass ratio of 2:1:0.125 and mixed thoroughly, and then a carbon-containing precursor mixture is formed after standing;

[0045] (2) The mixed carbon precursor is transferred to a fixed bed reactor for pyrolysis, nitrogen is introduced as the reaction atmosphere, the flow rate of nitrogen is 100 mL / min, the heating rate is 10 ℃ / min, the temperature is raised to 800 ℃, and the temperature is kept for 60 min; after pyrolysis, the bio-activated carbon is obtained after cooling;

[0046] (3) After collecting the bio-activated carbon, it is washed with dilute acid and deionized water for several times until it is neutral, and then it is dried in a blast drying oven to obtain a carbon molecular sieve adsorbent, which is denoted as HBAC-1

[0047] Example 2

[0048] The method for preparing a carbon molecular sieve with adjustable pore channel by binary activation of heavy oil is as follows: Figure 1

[0049] (1) The heavy component obtained by pyrolysis of pine wood is selected as the heavy oil sample, and the heavy oil, calcium citrate and potassium oxalate activator are weighed according to the mass ratio of 2:1:0.25 and mixed thoroughly, and then a carbon-containing precursor mixture is formed after standing; ​

[0050] (2) The mixed carbon precursor is transferred to a fixed bed reactor for pyrolysis, nitrogen is introduced as a reaction atmosphere, the flow rate of nitrogen is 100 mL / min, the heating rate is 10 ℃ / min, the temperature is raised to 800 ℃, and the temperature is kept for 60 min; after pyrolysis is completed, cooling is performed, and bioactive carbon is obtained;

[0051] (3) After the bioactive carbon is collected, dilute acid and deionized water are used for multiple washing until neutral, and after drying in a blast drying oven, a carbon molecular sieve adsorbent is obtained, which is recorded as HBAC-2.

[0052] Example 3

[0053] The method for preparing a carbon molecular sieve with adjustable pores by binary activation of heavy oil is as follows:

[0054] (1) The heavy component obtained by pyrolysis of pine wood is selected as a heavy oil sample, calcium citrate and potassium oxalate activators are respectively weighed according to a mass ratio of 2:1:0.5, and are fully mixed to form a carbon-containing precursor mixture;

[0055] (2) The mixed carbon precursor is transferred to a fixed bed reactor for pyrolysis, nitrogen is introduced as a reaction atmosphere, the flow rate of nitrogen is 100 mL / min, the heating rate is 10 ℃ / min, the temperature is raised to 800 ℃, and the temperature is kept for 60 min; after pyrolysis is completed, cooling is performed, and bioactive carbon is obtained;

[0056] (3) After the bioactive carbon is collected, dilute acid and deionized water are used for multiple washing until neutral, and after drying in a blast drying oven, a carbon molecular sieve adsorbent is obtained, which is recorded as HBAC-3.

[0057] Example 4

[0058] The method for preparing a carbon molecular sieve with adjustable pores by binary activation of heavy oil is as follows:

[0059] (1) The heavy component obtained by pyrolysis of pine wood is selected as a heavy oil sample, calcium citrate and potassium oxalate activators are respectively weighed according to a mass ratio of 2:1:1, and are fully mixed to form a carbon-containing precursor mixture;

[0060] (2) The mixed carbon precursor is transferred to a fixed bed reactor for pyrolysis, nitrogen is introduced as a reaction atmosphere, the flow rate of nitrogen is 100 mL / min, the heating rate is 10 ℃ / min, the temperature is raised to 800 ℃, and the temperature is kept for 60 min; after pyrolysis is completed, cooling is performed, and bioactive carbon is obtained;

[0061] (3) After the bioactive carbon is collected, dilute acid and deionized water are used for multiple washing until neutral, and after drying in a blast drying oven, a carbon molecular sieve adsorbent is obtained, which is recorded as HBAC-4.

[0062] Example 5

[0063] The method for preparing a carbon molecular sieve adsorbent with adjustable pore size by binary activation of heavy oil is as follows:

[0064] (1) The heavy component obtained by pyrolysis of pine wood was selected as the heavy oil sample, and the heavy oil, calcium citrate and potassium oxalate activators were weighed according to a mass ratio of 2:1:2 and mixed thoroughly to form a carbon-containing precursor mixture after standing;

[0065] (2) The mixed carbon precursor was transferred to a fixed bed reactor for pyrolysis, and nitrogen was introduced as the reaction atmosphere at a flow rate of 100 mL / min, the heating rate was 10 ℃ / min, and the temperature was raised to 800 ℃ and maintained for 60 min; after pyrolysis, the bioactive carbon was obtained after cooling;

[0066] (3) After collecting the bioactive carbon, the carbon molecular sieve adsorbent was obtained after washing with dilute acid and deionized water until neutral and drying in a blast drying oven, and was recorded as HBAC-5.

[0067] Comparative Example 1

[0068] In this comparative example, a commercial activated carbon (CAC) was selected as the blank control adsorbent.

[0069] Comparative Example 2

[0070] The preparation steps of the heavy oil-based activated carbon with unary activation in this comparative example are as follows:

[0071] (1) The heavy component obtained by pyrolysis of pine wood was selected as the heavy oil sample, and the heavy oil and potassium oxalate activator were weighed according to a mass ratio of 1:1 and mixed thoroughly to form a carbon-containing precursor mixture after standing;

[0072] (2) The mixed carbon precursor was transferred to a fixed bed reactor for pyrolysis, and nitrogen was introduced as the reaction atmosphere at a flow rate of 100 mL / min, the heating rate was 10 ℃ / min, and the temperature was raised to 800 ℃ and maintained for 60 min; after pyrolysis, the bioactive carbon was obtained after cooling;

[0073] (3) After collecting the bioactive carbon, the heavy oil-based activated carbon with unary activation was obtained after washing with dilute acid and deionized water until neutral and drying in a blast drying oven, and was recorded as HBAC-0.

[0074] Test Example 1

[0075] The microstructure of the carbon molecular sieve adsorbent was observed by a cold field emission scanning electron microscope, and the results are shown in Figure 2The micro-morphology of HBAC-0 is shown in Figure 1. Figure 2 (a), HBAC-0 is irregular granular, and there is a certain pore structure on the surface. The micro-morphology of HBAC-1 to HBAC-5 is shown in Figures 1 Figure 2 (b)-(f), which are all irregular granular structures. In addition, as the dosage of potassium oxalate activator increases, the pore structure on the surface is more developed.

[0076] The crystal structure of the carbon molecular sieve adsorbent was tested by an X-ray diffractometer, and the results are shown in Figure 2. Figure 3 As can be seen from the figure, the crystal structure of HBAC-0 can observe the existence of two typical crystal faces (002) and (100) of carbon. HBAC-1 to HBAC-5 can also observe the existence of two typical crystal faces (002) and (100) of carbon materials.

[0077] The pore structure of the carbon molecular sieve adsorbent was analyzed by a full-automatic specific surface and pore structure analyzer, and the results are shown in Figure 3. Figure 4 The nitrogen adsorption-desorption and pore size distribution curves of HBAC-0 adsorbent are shown in Figures 3 Figure 4 (a) and Figure 4 (d), and the specific surface area of the total pore and the specific surface area of the micropore are 1147 m 2 / g and 1050 m 2 / g, respectively, as shown in Figures 3 Figure 4 (b) and Figure 4 (c). The nitrogen adsorption-desorption and pore size distribution curves of the carbon molecular sieve adsorbent (HBAC-1 to HBAC-5) are shown in Figures 3 Figure 4 (a) and Figure 4 (e)-(i), it can be clearly found that the pore size is mainly concentrated around 0.8 nm, which has obvious molecular sieve structure characteristics. The specific surface area of the carbon molecular sieve is shown in Figures 3 Figure 4 (b) and Figure 4 (c), in which the specific surface area of the total pore and the specific surface area of the micropore of HBAC-5 are 1857 m 2 / g and 1559 m 2 / g, respectively.

[0078] Test Example 2

[0079] This test example tests the adsorption performance of each sample in practical application, and the steps are as follows:

[0080] 1) 50 mg of sample was weighed and added to a conical flask with 50 mL of MB with a specific concentration (25-1000 mg / L), and transferred to a shaker to adsorb for a certain time (0-1440 min) at room temperature;

[0081] 2) After the end of the adsorption process, the solution was subjected to solid-liquid separation to obtain a liquid phase without solids;

[0082] 3) The pure liquid phase was transferred to a cuvette and its absorbance was tested using a UV spectrophotometer, with a UV wavelength of 664 nm.

[0083] Figure 5 The equilibrium adsorption capacity and removal rate of MB of each adsorbent sample (CAC, HBAC-0 to HBAC-5) when the initial concentration of MB was 1000 mg / L are shown in the figure. It can be seen from the figure that the equilibrium adsorption capacity of CAC can reach 428.9 mg / g, and the removal rate of MB is 42.9%. The equilibrium adsorption capacity of HBAC-0 adsorbent obtained by activating heavy oil with a monobasic activator is only 356.7 mg / g, and the removal rate of MB is 35.7%. The adsorption capacity of the carbon molecular sieve adsorbent (HBAC-1 to HBAC-5) obtained by activating heavy oil with a binary activator is greatly improved. Among them, the adsorption capacity and removal rate of HBAC-5 reached the maximum, which were 819.3 mg / g and 81.9% respectively, which were 1.91 times of the commercial activated carbon and 2.30 times of the monobasic activated HBAC-0 adsorbent.

[0084] The adsorption capacity of each adsorbent sample for MB at different initial concentrations of MB is shown in Figure 6 (a), it can be seen that with the increase of the initial concentration of MB, the adsorption capacity of each adsorbent for MB also shows a gradually increasing trend. When the initial concentration of MB reaches 800 mg / L, the adsorption capacity of HBAC-5 reaches 724.5 mg / g, which is 1.70 times and 1.97 times of CAC (425.8 mg / g) and HBAC-0 (368.3 mg / g) respectively. Figure 6 (b), the results show that with the increase of adsorption time, the adsorption capacity of each adsorbent for MB also shows a gradually increasing trend. Among them, the adsorption capacities of HBAC-3, HBAC-4 and HBAC-5 adsorbents after 24 h of adsorption are 674.6 mg / g, 676.3 mg / g and 724.5 mg / g respectively, which are much higher than those of CAC (425.9 mg / g) and HBAC-0 (356.7 mg / g).

[0085] Compared with the prior art, the method for preparing a carbon molecular sieve with adjustable pores by activating heavy oil in a binary green way has the characteristics of complex composition, high carbon content, low ash content, good thermal plasticity and easy polymerization of heavy oil, which makes up for the disadvantages of high viscosity, poor flowability and difficulty in direct utilization, so that the waste heavy oil can be efficiently converted and used for water purification; at the same time, the synergistic coupling effect between the binary green activators is fully utilized to promote the efficient activation reaction. The biomass-derived heavy oil used in the application has a wide source, high carbon content and high viscosity, and is in a semi-liquid state, which can perfectly dissolve the binary organic salt activator, so that the macromolecular components in the heavy oil can fully contact with the activator molecules, which is beneficial to the efficient activation of the activator and promotes the efficient activation reaction, which is beneficial to the formation of carbon molecular sieve with uniform pore structure and concentrated pore size distribution, and greatly improves the quality of carbon products. Then, the carbon molecular sieve is applied to efficient water treatment, which effectively treats waste heavy oil and simultaneously purifies dye wastewater, realizing the resource utilization of the two pollutants of waste heavy oil and dye wastewater.

[0086] In summary, the application innovatively uses a two-component green activator to compound with waste heavy oil, and successfully prepares a carbon-based molecular sieve material with a directional pore structure through a programmed temperature pyrolysis activation coupling post-treatment process. The obtained material has a remarkable three-dimensional hierarchical pore system, and the pore size distribution is highly concentrated compared with traditional carbon materials. The material exhibits excellent adsorption performance for typical organic pollutants in water, methylene blue, with a maximum adsorption capacity of 819 mg / g, which is 91% higher than that of commercial activated carbon, and has excellent adsorption kinetic properties. The technology has the advantages of simple preparation process, green environmental protection and low cost, and not only realizes the resource utilization of agricultural and forestry waste, but also provides an innovative solution for the development of efficient water treatment adsorption materials, with significant environmental and economic benefits.

[0087] The above describes the preferred embodiments of the application in detail. It should be understood that those skilled in the art can make many modifications and changes without creative labor according to the concept of the application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment based on the prior art according to the concept of the application shall be within the protection scope determined by the claims.

Claims

1. A method for preparing a carbon molecular sieve with adjustable pore by binary activation of heavy oil, characterized in that, The method comprises the following steps: (1) selecting heavy oil from pine pyrolysis as heavy oil, mixing the heavy oil and a binary activator, and standing to form a carbon-containing precursor mixture; wherein the binary activator is calcium citrate and potassium oxalate; the mass ratio of the heavy oil, the calcium citrate and the potassium oxalate is 2:1:0.25-2; (2) pyrolysis and activation of the carbon-containing precursor mixture under an inert atmosphere, cooling after pyrolysis, and obtaining bioactive carbon; the initial temperature of pyrolysis is room temperature, the heating rate is 5-10 ℃ / min, the pyrolysis temperature is 600-800 ℃, and the holding time is 10-60 min; (3) washing and drying the bioactive carbon to obtain carbon molecular sieves.

2. The method for preparing a carbon molecular sieve with adjustable pore size by binary activation of heavy oil according to claim 1, characterized in that: In the step (1), the mixing time is 5-30 min, and the standing time is 5-30 min.

3. The method for preparing a carbon molecular sieve with adjustable pore size by binary activation of heavy oil according to claim 1, characterized in that: In the step (2), the gas type of the inert atmosphere includes at least one of nitrogen, argon and helium; and the gas flow rate is 50-100 mL / min.

4. The method for preparing a carbon molecular sieve with adjustable pore size by binary activation of heavy oil according to claim 1, characterized in that: In the step (3), the bioactive carbon is washed with dilute acid and water, and then dried at 100-150 ℃ to obtain carbon molecular sieves.

5. The method for preparing a carbon molecular sieve with adjustable pore size by binary activation of heavy oil according to claim 4, characterized in that: The type of the dilute acid includes at least one of hydrochloric acid, nitric acid and sulfuric acid; and the concentration of the dilute acid is 0.1-1 mol / L.

6. A carbon molecular sieve characterized by: The carbon molecular sieves are prepared by the method according to any one of claims 1-5.

7. Use of the carbon molecular sieves according to claim 6 as adsorbent materials in water treatment.

8. Use according to claim 7, characterized in that: The carbon molecular sieves are used as adsorbent materials to remove dye pollutants in wastewater.

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