Petroleum-based activated carbon and preparation method and application thereof

Abstract

The present application relates to a kind of petroleum-based activated carbon and its preparation method and application, the preparation method of the petroleum-based activated carbon includes the following steps: (1) uniformly mixed composite activating agent and petroleum-based raw material, sequentially through pre-activation, activation, washing and drying to obtain petroleum-based activated carbon precursor;(2) the petroleum-based activated carbon precursor obtained in step (1) is immersed in metal salt solution, after solid-liquid separation, drying obtains the petroleum-based activated carbon;Step (1) the composite activating agent includes potassium hydroxide, potassium chloride, potassium carbonate, potassium bicarbonate or the combination of at least two in organic potassium salt;Step (2) the metal salt solution is obtained by mixing metal salt and solvent and adjusting acid.The present application introduces composite activating agent to make petroleum-based activated carbon have higher microporosity;By loading metal in petroleum-based activated carbon, the adsorption capacity of the obtained petroleum-based activated carbon is enhanced, and the preparation process is simple and highly feasible.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, and relates to activated carbon, its preparation method and application, specifically to petroleum-based activated carbon, its preparation method and application. Background Technology

[0002] Volatile organic compounds (VOCs) are one of the main sources of air pollutants. Among them, chlorinated compounds are carcinogenic, mutagenic, and genotoxic. Currently, common methods for treating chlorinated compounds can be divided into non-destructive and destructive methods. Non-destructive methods mainly include absorption, adsorption, membrane separation, and condensation, while destructive methods include catalytic oxidation, biodegradation, and thermal oxidation. Adsorption methods have received widespread attention and application due to their wide applicability, low cost, simple operation, mild reaction conditions, and high recovery rates.

[0003] Among adsorption materials, high-microporous activated carbon with high specific surface area is particularly suitable for gas adsorption due to its well-developed pore structure, suitable pore size distribution, and large adsorption capacity. It can be used for adsorption of inorganic chlorine-containing compounds, such as in the purification of chlorosilanes. Petroleum-based activated carbon is prepared from petroleum coke and pitch coke, the high-temperature cracking products of heavy petroleum components such as petroleum residue and petroleum asphalt. These raw materials are characterized by stable yield, wide distribution, high carbon content, and low price, making them ideal carbon precursors for preparing high specific surface area activated carbon.

[0004] CN 1091073A discloses a method for preparing activated carbon for adsorbing and storing methane. This method uses petroleum coke or pitch coke as raw material and KOH as an activating agent to obtain powdered activated carbon with a high specific surface area. The powdered activated carbon is then mixed with a binder at a ratio of 1:0.30-0.60, pressed into shape at 20-130℃ and 50-320MPa pressure, carbonized at 700-1000℃, and then activated using steam or carbon dioxide at 700-1000℃ to obtain shaped activated carbon with a high specific surface area. This method yields activated carbon with a high specific surface area, but its applications have certain limitations.

[0005] CN 111377445A discloses a petroleum coke-based activated carbon material and its preparation method. The preparation method involves introducing ammonium phosphate into petroleum coke, drying it, and then pretreating it. The resulting sample is then mixed with an activating agent, uniformly mixed, and activated. Finally, the activated carbon is obtained by washing and drying. However, this method involves a complex and costly process for treating the petroleum coke material, and the microporous surface area ratio of the obtained activated carbon material needs further improvement.

[0006] In view of the shortcomings of existing technologies, there is an urgent need to provide a petroleum-based activated carbon with high specific surface area, high microporosity, low cost, and excellent adsorption and recycling performance. Summary of the Invention

[0007] The purpose of this invention is to provide a petroleum-based activated carbon, its preparation method, and its application. By introducing a composite activator and simultaneously performing reasonable metal modification, the resulting petroleum-based activated carbon exhibits excellent adsorption and recycling performance. The preparation method is simple to operate, low in cost, and suitable for industrial production.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing petroleum-based activated carbon, the method comprising the following steps:

[0010] (1) A composite activator and petroleum-based raw materials are uniformly mixed, and then pre-activated, activated, washed and dried to obtain a petroleum-based activated carbon precursor.

[0011] (2) The petroleum-based activated carbon precursor obtained in step (1) is immersed in a metal salt solution, and after solid-liquid separation, it is dried to obtain the petroleum-based activated carbon.

[0012] The composite activator in step (1) includes a combination of at least two of potassium hydroxide, potassium chloride, potassium carbonate, potassium bicarbonate, or organic potassium salts;

[0013] The metal salt solution in step (2) is obtained by mixing the metal salt with a solvent and adjusting the acidity.

[0014] The method for preparing petroleum-based activated carbon described in this invention can control the pore size distribution range of petroleum-based activated carbon by introducing a composite activator, thereby giving it a high microporosity. By loading metal onto activated carbon, the resulting modified activated carbon not only has its own physical adsorption capacity, but the loaded metal also interacts with the target adsorbent, enhancing the activated carbon's adsorption capacity for the adsorbent and increasing the adsorbate transport rate.

[0015] The composite activator includes a combination of at least two of potassium hydroxide, potassium chloride, potassium carbonate, potassium bicarbonate, or an organic potassium salt. Typical but non-limiting combinations include a combination of potassium hydroxide and potassium chloride, a combination of potassium carbonate and potassium bicarbonate, a combination of potassium hydroxide, potassium chloride, and potassium carbonate, a combination of potassium hydroxide, potassium chloride, potassium carbonate, and potassium bicarbonate, or a combination of potassium hydroxide, potassium chloride, potassium carbonate, potassium bicarbonate, and an organic potassium salt.

[0016] Preferably, the mass ratio of the composite activator to the petroleum-based raw material in step (1) is (3-6):1, for example, it can be 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1 or 6:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] If the amount of composite activator used during the activation process is too small, a good pore-forming effect cannot be achieved; if the amount of composite activator used is too large, its excessive activation effect will lead to the formation of a large number of mesoporous structures, making it impossible to achieve the high microporosity of the petroleum-based activated carbon. Therefore, this invention controls the ratio of composite activator to petroleum-based raw materials within a reasonable range.

[0018] Preferably, the composite activator in step (1) includes a combination of at least two of potassium hydroxide, potassium carbonate, potassium bicarbonate, or an organic potassium salt. Typical but non-limiting combinations include a combination of potassium hydroxide and potassium carbonate, a combination of potassium bicarbonate and an organic potassium salt, a combination of potassium hydroxide, potassium carbonate, and potassium bicarbonate, or a combination of potassium hydroxide, potassium carbonate, potassium bicarbonate, and an organic potassium salt.

[0019] Preferably, the organic potassium salt includes C1-C16 organic potassium salts, and more preferably potassium citrate.

[0020] Preferably, the composite activator in step (1) comprises a first activator and a second activator in a mass ratio of (1-5):1, wherein the first activator and the second activator have different compositions.

[0021] The mass ratio of the first activator to the second activator is (1-5):1, for example, it can be 1:1, 2:1, 3:1, 4:1 or 5:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] The use of the composite activator improves the problem of mesopores that are easily generated by single activators, making the pore distribution of petroleum-based activated carbon concentrated and avoiding excessive pore expansion.

[0023] Preferably, the petroleum-based raw material in step (1) includes any one or a combination of at least two of petroleum coke, pitch coke, or mesophase carbon microspheres. Typical but non-limiting combinations include a combination of petroleum coke and pitch coke, a combination of pitch coke and mesophase carbon microspheres, or a combination of petroleum coke, pitch coke, and mesophase carbon microspheres.

[0024] Preferably, the uniform mixing method described in step (1) includes solid-solid grinding mixing and solid-liquid immersion mixing.

[0025] Preferably, the pre-activation step in step (1) includes: heating to 300-500°C at a rate of 4-6°C / min under a protective atmosphere and holding at that temperature for 0.1-2 hours.

[0026] The activation heating rate is 4-6℃ / min, for example, it can be 4℃ / min, 4.5℃ / min, 5℃ / min, 5.5℃ / min or 6℃ / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] The endpoint of the temperature rise is 300-500℃, for example, it can be 300℃, 350℃, 400℃, 450℃ or 500℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] The heat preservation time is 0.1-2h, for example, it can be 0.1h, 0.5h, 1h, 1.5h or 2h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] The pre-activation step described in this invention enables petroleum-based raw materials to form an initial porous structure, which is beneficial for the subsequent formation of micropores.

[0030] Preferably, the activation step in step (1) includes: heating to 550-1000°C at a rate of 4-6°C / min under a protective atmosphere and holding at that temperature for 0.5-4 hours.

[0031] The activation heating rate is 4-6℃ / min, for example, it can be 4℃ / min, 4.5℃ / min, 5℃ / min, 5.5℃ / min or 6℃ / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] The endpoint of the temperature rise is 550-1000℃, for example, it can be 550℃, 600℃, 700℃, 800℃, 900℃ or 1000℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] The heat preservation time is 0.5-4h, for example, it can be 0.5h, 1h, 2h, 3h or 4h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] After the activation step described in step (1), the mixture is allowed to cool naturally to room temperature under a protective atmosphere.

[0035] Preferably, the protective atmosphere uses nitrogen and / or an inert gas.

[0036] Preferably, in the pre-activation step (1), the flow rate of the protective atmosphere gas is 90-110 mL / min, for example, it can be 90 mL / min, 95 mL / min, 100 mL / min, 105 mL / min or 110 mL / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] Preferably, in the activation step (1), the flow rate of the protective atmosphere gas is 90-110 mL / min, for example, it can be 90 mL / min, 95 mL / min, 100 mL / min, 105 mL / min or 110 mL / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0038] Preferably, the washing step (1) includes: the activated material is sequentially acid-washed and water-washed until the filtrate is neutral.

[0039] Preferably, the acid used for pickling includes any one or at least two combinations of nitric acid, hydrochloric acid, sulfuric acid, hypochlorous acid, or hydrogen peroxide. Typical but non-limiting combinations include combinations of nitric acid and hydrochloric acid, hypochlorous acid and hydrogen peroxide, combinations of nitric acid, hydrochloric acid, and sulfuric acid, combinations of hydrochloric acid, sulfuric acid, hypochlorous acid, and hydrogen peroxide, or combinations of nitric acid, hydrochloric acid, sulfuric acid, hypochlorous acid, and hydrogen peroxide.

[0040] Preferably, the concentration of the acid used for pickling is 0.01-5 mol / L, for example, it can be 0.01 mol / L, 0.1 mol / L, 0.5 mol / L, 1 mol / L or 5 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0041] Preferably, the water used for washing includes distilled water.

[0042] Preferably, the drying temperature in step (1) is 100-120°C, for example, it can be 100°C, 105°C, 110°C, 115°C or 120°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] Preferably, the drying time in step (1) is 1-12 hours, for example, 1 hour, 3 hours, 5 hours, 8 hours, 10 hours or 12 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0044] Preferably, the immersion temperature in step (2) is 20-50°C, for example, it can be 20°C, 25°C, 30°C, 40°C or 50°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0045] Preferably, the soaking time in step (2) is 22-26 hours, for example, 22 hours, 23 hours, 24 hours, 25 hours or 26 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0046] Preferably, the drying temperature in step (2) is 100-110℃, for example, it can be 100℃, 102℃, 105℃, 108℃ or 110℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0047] Preferably, the drying time in step (2) is 22-26 hours, for example, 22 hours, 23 hours, 24 hours, 25 hours or 26 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0048] Preferably, the mass-volume ratio of the petroleum-based activated carbon precursor to the metal salt solution in step (2) is 1g:(0.01-0.6)L, for example, it can be 1g:0.01L, 1g:0.05L, 1g:0.1L, 1g:0.3L or 1g:0.6L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0049] Preferably, the concentration of the metal salt in the metal salt solution in step (2) is 0.001-0.5 mol / L, for example, it can be 0.001 mol / L, 0.01 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0050] The concentration of the metal salt in the metal salt solution described in this invention is selected within a reasonable range to ensure that the petroleum-based activated carbon precursor is fully impregnated with the metal salt, thereby improving the adsorption of chlorine-containing compounds.

[0051] Preferably, the metal salt in the metal salt solution in step (2) includes any one or a combination of at least two of the metal nitrates, sulfates or chlorides. Typical but non-limiting combinations include combinations of nitrates and sulfates, combinations of sulfates and chlorides, or combinations of nitrates, sulfates and chlorides.

[0052] Preferably, the metal used includes any one or a combination of at least two of iron, aluminum, magnesium, zinc, lanthanum, cerium or yttrium. Typical but non-limiting combinations include combinations of iron and aluminum, magnesium, zinc and lanthanum, zinc, lanthanum, cerium and yttrium, iron, aluminum, magnesium, zinc and lanthanum, aluminum, magnesium, zinc, lanthanum, cerium and yttrium, or iron, aluminum, magnesium, zinc, lanthanum, cerium and yttrium.

[0053] This invention introduces metal-modified activated carbon, which has a smaller impact on pore blockage. At the same time, the addition of metal helps to improve the saturated adsorption capacity of petroleum-based activated carbon for chlorine-containing compounds.

[0054] Preferably, the solvent includes deionized water.

[0055] Preferably, the acid used for acid adjustment includes hydrochloric acid.

[0056] Preferably, the amount of hydrochloric acid added is such that the pH value of the mixed solution is 4.5-5.5, for example, it can be 4.5, 4.8, 5, 5.2 or 5.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0057] The acid-adjusting step prevents metal ions from hydrolyzing and forming precipitates, thereby avoiding metal blockage of the pore structure.

[0058] As a preferred embodiment of the preparation method described in the first aspect of the present invention, the preparation method includes the following steps:

[0059] (1) A composite activator and petroleum-based raw material with a mass ratio of (3-6):1 are uniformly mixed, and then pre-activated, activated, acid-washed and water-washed until the filtrate is neutral and dried at 100-120℃ for 1-12h to obtain a petroleum-based activated carbon precursor.

[0060] The composite activator comprises a combination of at least two of potassium hydroxide, potassium chloride, potassium carbonate, potassium bicarbonate, or organic potassium salts; the pre-activation step comprises: heating to 300-500℃ at a rate of 4-6℃ / min under a protective atmosphere and holding at that temperature for 0.1-2h; the activation step comprises: heating to 550-1000℃ at a rate of 4-6℃ / min under a protective atmosphere and holding at that temperature for 0.5-4h; in the pre-activation, the flow rate of the gas used in the protective atmosphere is 90-110mL / min; in the activation, the flow rate of the gas used in the protective atmosphere is 90-110mL / min.

[0061] (2) The petroleum-based activated carbon precursor obtained in step (1) is immersed in a metal salt solution at 20-50°C for 22-26 hours. After solid-liquid separation, it is dried at 100-110°C for 22-26 hours to obtain the petroleum-based activated carbon.

[0062] The mass-to-volume ratio of the petroleum-based activated carbon precursor to the metal salt solution is 1 g:(0.01-0.6) L; the metal salt solution is obtained by mixing the metal salt with a solvent and adjusting the pH; the concentration of the metal salt in the metal salt solution is 0.001-0.5 mol / L; the acid used for adjusting the pH includes hydrochloric acid; the amount of hydrochloric acid added is such that the pH of the mixed solution is 4.5-5.5.

[0063] Secondly, the present invention provides petroleum-based activated carbon obtained by the preparation method described in the first aspect, wherein the specific surface area of ​​the petroleum-based activated carbon is 2000-2600 m². 2 / g; microporosity 90-97%; pore size range 0.5-1.5nm.

[0064] The petroleum-based activated carbon of this invention is composed of micron-sized particles with a layered structure, which has a large specific surface area, high microporosity and excellent adsorption capacity. At the same time, it has a long cycle life and is suitable for industrial production.

[0065] The specific surface area of ​​the petroleum-based activated carbon is 2000-2600 m². 2 / g, for example, could be 2000m 2 / g、2100m 2 / g、2200m 2 / g、2300m 2 / g、2400m 2 / g、2500m 2 / g or 2600m 2 / g, but not limited to the listed values, other unlisted values ​​within the range also apply.

[0066] The microporosity of the petroleum-based activated carbon is 90-97%, for example, it can be 90%, 91%, 92%, 93%, 94%, 95%, 96% or 97%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0067] The pore size of the petroleum-based activated carbon is in the range of 0.5-1.5 nm, for example, it can be 0.5 nm, 0.8 nm, 1 nm, 1.2 nm or 1.5 nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0068] Thirdly, the present invention provides the application of petroleum-based activated carbon as described in the second aspect, wherein the petroleum-based activated carbon is used to adsorb chlorine-containing compounds.

[0069] The chlorine-containing compounds include inorganic chlorine-containing compounds and / or chlorine-containing volatile organic compounds.

[0070] Compared with the prior art, the present invention has the following beneficial effects:

[0071] (1) The method for preparing petroleum-based activated carbon described in this invention can control the pore size distribution range of petroleum-based activated carbon by introducing a composite activator, so that it has a high microporosity; by loading metal onto activated carbon, the adsorption capacity of the obtained petroleum-based activated carbon for adsorbates is enhanced, and the preparation process is simple and highly feasible.

[0072] (2) The petroleum-based activated carbon of the present invention has a large specific surface area, high microporosity and excellent adsorption capacity, with a specific surface area of ​​up to 2813 m². 2 With a microporosity of up to 99% and a saturated adsorption capacity of up to 627 mg / g, it is suitable for the adsorption treatment of chlorine-containing compounds. Attached Figure Description

[0073] Figure 1 This is a SEM image of the petroleum-based activated carbon provided in Example 1;

[0074] Figure 2 This is a SEM image of the petroleum-based activated carbon provided in Example 12;

[0075] Figure 3 This is a SEM image of the petroleum-based activated carbon provided in Example 13;

[0076] Figure 4 This is a SEM image of the petroleum-based activated carbon provided in Example 14;

[0077] Figure 5 The image shows a SEM image of the petroleum-based activated carbon provided in Comparative Example 1.

[0078] Figure 6 This is the nitrogen adsorption-desorption isotherm diagram of petroleum-based activated carbon provided in Example 1;

[0079] Figure 7 This is a pore size distribution diagram of the petroleum-based activated carbon provided in Example 1. Detailed Implementation

[0080] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0081] Example 1

[0082] This embodiment provides a petroleum-based activated carbon, the preparation method of which includes the following steps:

[0083] (1) A composite activator and petroleum coke with a mass ratio of 4:1 were uniformly mixed, and then pre-activated, activated, washed with hydrochloric acid and distilled water until the filtrate was neutral and dried at 110°C for 6 hours to obtain a petroleum-based activated carbon precursor.

[0084] The composite activator comprises potassium hydroxide and potassium carbonate in a mass ratio of 3:1; the pre-activation step includes: heating to 400°C at a rate of 5°C / min under nitrogen gas flow protection of 100 mL / min, and holding at this temperature for 1 h; the activation step includes: heating to 750°C at a rate of 5°C / min under nitrogen gas flow protection of 100 mL / min, and holding at this temperature for 2 h.

[0085] (2) The petroleum-based activated carbon precursor obtained in step (1) was immersed in ferric chloride solution at 30°C for 24 hours. After solid-liquid separation, it was dried at 105°C for 24 hours to obtain the petroleum-based activated carbon.

[0086] The mass-to-volume ratio of the petroleum-based activated carbon precursor to the ferric chloride solution is 1 g: 0.2 L; the ferric chloride solution is obtained by mixing ferric chloride and deionized water and adjusting the pH with hydrochloric acid; the concentration of ferric chloride in the ferric chloride solution is 0.1 mol / L; the amount of hydrochloric acid added is such that the pH of the mixed solution is 5.

[0087] The SEM image of the petroleum-based activated carbon is shown below. Figure 1 As shown in the figure, the petroleum-based activated carbon is composed of micron-sized particles with a layered structure, mainly featuring a slit-like pore structure. The sample surface is smooth and free of obvious metal particles, indicating that the modified metal particles are small in size and uniformly dispersed. The nitrogen adsorption-desorption isotherm and pore size distribution diagram of the petroleum-based activated carbon are shown in the figure. Figure 6 , Figure 7 As shown in the figure, the sample exhibits typical type I adsorption isotherm characteristics, and the pore structure of petroleum-based activated carbon is mainly micropores.

[0088] Example 2

[0089] This embodiment provides a petroleum-based activated carbon, the preparation method of which includes the following steps:

[0090] (1) A composite activator and petroleum coke with a mass ratio of 3.5:1 were uniformly mixed and then pre-activated, activated, washed with hydrochloric acid and distilled water until the filtrate was neutral and dried at 105℃ for 9 hours to obtain a petroleum-based activated carbon precursor.

[0091] The composite activator comprises potassium hydroxide and potassium carbonate in a mass ratio of 2:1; the pre-activation step includes: heating to 350°C at a rate of 4.5°C / min under nitrogen gas flow protection of 95 mL / min, and holding at this temperature for 1.5 h; the activation step includes: heating to 650°C at a rate of 4.5°C / min under nitrogen gas flow protection of 95 mL / min, and holding at this temperature for 3 h.

[0092] (2) The petroleum-based activated carbon precursor obtained in step (1) is immersed in ferric chloride solution at 25°C for 25 h, and after solid-liquid separation, it is dried at 102°C for 25 h to obtain the petroleum-based activated carbon.

[0093] The mass-to-volume ratio of the petroleum-based activated carbon precursor to the ferric chloride solution is 1 g: 0.1 L; the ferric chloride solution is obtained by mixing ferric chloride and deionized water and adjusting the pH with hydrochloric acid; the concentration of ferric chloride in the ferric chloride solution is 0.3 mol / L; the amount of hydrochloric acid added is such that the pH of the mixed solution is 4.8.

[0094] Example 3

[0095] This embodiment provides a petroleum-based activated carbon, the preparation method of which includes the following steps:

[0096] (1) A composite activator and petroleum coke with a mass ratio of 5:1 were uniformly mixed and then pre-activated, activated, washed with hydrochloric acid and distilled water until the filtrate was neutral and dried at 115°C for 3 hours to obtain a petroleum-based activated carbon precursor.

[0097] The composite activator comprises potassium hydroxide and potassium carbonate in a mass ratio of 4:1; the pre-activation step includes: heating to 450°C at a rate of 5.5°C / min under nitrogen gas flow protection of 105 mL / min, and holding at this temperature for 0.5 h; the activation step includes: heating to 900°C at a rate of 5.5°C / min under nitrogen gas flow protection of 105 mL / min, and holding at this temperature for 1 h.

[0098] (2) The petroleum-based activated carbon precursor obtained in step (1) was immersed in ferric chloride solution at 40°C for 23 hours. After solid-liquid separation, it was dried at 108°C for 23 hours to obtain the petroleum-based activated carbon.

[0099] The mass-to-volume ratio of the petroleum-based activated carbon precursor to the ferric chloride solution is 1 g: 0.4 L; the ferric chloride solution is obtained by mixing ferric chloride and deionized water and adjusting the pH with hydrochloric acid; the concentration of ferric chloride in the ferric chloride solution is 0.01 mol / L; the amount of hydrochloric acid added is such that the pH of the mixed solution is 5.2.

[0100] Example 4

[0101] This embodiment provides a petroleum-based activated carbon, the preparation method of which includes the following steps:

[0102] (1) A composite activator and petroleum coke with a mass ratio of 3:1 were uniformly mixed, and then pre-activated, activated, washed with hydrochloric acid and distilled water until the filtrate was neutral and dried at 100°C for 12 hours to obtain a petroleum-based activated carbon precursor.

[0103] The composite activator comprises potassium hydroxide and potassium carbonate in a mass ratio of 1:1; the pre-activation step includes: heating to 300°C at a rate of 4°C / min under nitrogen gas flow protection of 90 mL / min, and holding at this temperature for 2 h; the activation step includes: heating to 550°C at a rate of 4°C / min under nitrogen gas flow protection of 90 mL / min, and holding at this temperature for 4 h.

[0104] (2) The petroleum-based activated carbon precursor obtained in step (1) was immersed in ferric chloride solution at 20°C for 26 hours. After solid-liquid separation, it was dried at 100°C for 26 hours to obtain the petroleum-based activated carbon.

[0105] The mass-to-volume ratio of the petroleum-based activated carbon precursor to the ferric chloride solution is 1 g: 0.01 L; the ferric chloride solution is obtained by mixing ferric chloride and deionized water and adjusting the pH with hydrochloric acid; the concentration of ferric chloride in the ferric chloride solution is 0.5 mol / L; the amount of hydrochloric acid added is such that the pH of the mixed solution is 4.5.

[0106] Example 5

[0107] This embodiment provides a petroleum-based activated carbon, the preparation method of which includes the following steps:

[0108] (1) A composite activator and petroleum coke with a mass ratio of 6:1 were uniformly mixed and then pre-activated, activated, washed with hydrochloric acid and distilled water until the filtrate was neutral and dried at 120°C for 1 hour to obtain a petroleum-based activated carbon precursor.

[0109] The composite activator comprises potassium hydroxide and potassium carbonate in a mass ratio of 5:1; the pre-activation step includes: heating to 500°C at a rate of 6°C / min under nitrogen gas flow protection of 110 mL / min, and holding at that temperature for 0.1 h; the activation step includes: heating to 1000°C at a rate of 6°C / min under nitrogen gas flow protection of 110 mL / min, and holding at that temperature for 0.5 h.

[0110] (2) The petroleum-based activated carbon precursor obtained in step (1) was immersed in ferric chloride solution at 50°C for 22 h, and after solid-liquid separation, it was dried at 110°C for 22 h to obtain the petroleum-based activated carbon.

[0111] The mass-to-volume ratio of the petroleum-based activated carbon precursor to the ferric chloride solution is 1 g: 0.6 L; the ferric chloride solution is obtained by mixing ferric chloride and deionized water and adjusting the pH with hydrochloric acid; the concentration of ferric chloride in the ferric chloride solution is 0.001 mol / L; the amount of hydrochloric acid added is such that the pH of the mixed solution is 5.5.

[0112] Example 6

[0113] This embodiment provides a petroleum-based activated carbon. The difference between this embodiment and Embodiment 1 is that, except for adjusting the mass ratio of the composite activator to petroleum coke in step (1) to 2:1, everything else is the same as in Embodiment 1.

[0114] Example 7

[0115] This embodiment provides a petroleum-based activated carbon. The difference between this embodiment and Embodiment 1 is that, except for adjusting the mass ratio of the composite activator to petroleum coke in step (1) to 7:1, everything else is the same as in Embodiment 1.

[0116] Example 8

[0117] This embodiment provides a petroleum-based activated carbon. The difference between this embodiment and Embodiment 1 is that, except for adjusting the concentration of ferric chloride in the ferric chloride solution described in step (2) to 0.0005 mol / L, the rest is the same as in Embodiment 1.

[0118] Example 9

[0119] This embodiment provides a petroleum-based activated carbon. The difference between this embodiment and Embodiment 1 is that, except for adjusting the concentration of ferric chloride in the ferric chloride solution described in step (2) to 1 mol / L, the rest is the same as in Embodiment 1.

[0120] Example 10

[0121] This embodiment provides a petroleum-based activated carbon. The difference between this embodiment and Embodiment 1 is that, except for replacing potassium carbonate in the composite activator described in step (1) with potassium chloride, the rest is the same as in Embodiment 1.

[0122] Example 11

[0123] This embodiment provides a petroleum-based activated carbon. The difference between this embodiment and Embodiment 1 is that, except for replacing potassium carbonate in the composite activator described in step (1) with potassium isobutyrate, everything else is the same as in Embodiment 1.

[0124] Example 12

[0125] This embodiment provides a petroleum-based activated carbon. The difference between this embodiment and Embodiment 1 is that, except for replacing the ferric chloride in step (2) with copper chloride to obtain a copper chloride solution of equal concentration, the rest is the same as in Embodiment 1.

[0126] The SEM image of the petroleum-based activated carbon is shown below. Figure 2 As shown in the figure, the petroleum-based activated carbon is composed of micron-sized particles with a layered structure, mainly with a slit-like pore structure. The sample surface is smooth and there are no obvious metal particles, indicating that the modified metal particles are small in size and uniformly dispersed.

[0127] Example 13

[0128] This embodiment provides a petroleum-based activated carbon. The difference from Example 1 is that, except that the ferric chloride in step (2) is replaced with lanthanum nitrate to obtain a lanthanum nitrate solution of equal concentration, the rest is the same as in Example 1.

[0129] The SEM image of the petroleum-based activated carbon is shown below. Figure 3 As shown in the figure, the petroleum-based activated carbon is composed of micron-sized particles with a layered structure, mainly with a slit-like pore structure. The sample surface is smooth and there are no obvious metal particles, indicating that the modified metal particles are small in size and uniformly dispersed.

[0130] Example 14

[0131] This embodiment provides a petroleum-based activated carbon. The difference from Embodiment 1 is that, except for replacing the ferric chloride in step (2) with cerium nitrate to obtain a cerium nitrate solution of equal concentration, the rest is the same as in Embodiment 1.

[0132] The SEM image of the petroleum-based activated carbon is shown below. Figure 4 As shown in the figure, the petroleum-based activated carbon is composed of micron-sized particles with a layered structure, mainly cylindrical pore structure. The sample surface is smooth and there are no obvious metal particles, indicating that the modified metal particles are small in size and uniformly dispersed.

[0133] Comparative Example 1

[0134] This comparative example provides a petroleum-based activated carbon. The difference between this example and Example 1 is that step (2) is omitted in the preparation method, while the rest are the same as in Example 1.

[0135] The SEM image of the petroleum-based activated carbon is shown below. Figure 5 As shown in the figure, petroleum-based activated carbon is composed of micron-sized particles with a layered structure, mainly consisting of slit-like pores.

[0136] Comparative Example 2

[0137] This comparative example provides a petroleum-based activated carbon. The difference between this example and Example 1 is that, except for the composite activator in step (1) being changed to a single activator, potassium hydroxide, everything else is the same as in Example 1.

[0138] Comparative Example 3

[0139] This comparative example provides a petroleum-based activated carbon. The difference between this example and Example 1 is that the preparation method does not include a pre-activation step, while the rest is the same as Example 1.

[0140] Comparative Example 4

[0141] This comparative example provides a petroleum-based activated carbon. The difference between this example and Example 1 is that the ferric chloride solution in step (2) is obtained by mixing ferric chloride and deionized water, without the acid adjustment step. All other steps are the same as in Example 1.

[0142] The petroleum-based activated carbons provided in Examples 1-14 and Comparative Examples 1-4 were tested for specific surface area, pore structure parameters, and adsorption performance according to GB / T7702.20 "Test Methods for Coal-based Granular Activated Carbon - Determination of Pore Volume and Specific Surface Area". The results are shown in Table 1; where: S BET S is the specific surface area of ​​the sample. mic S represents the specific surface area of ​​the micropores. mic / S BET V represents the percentage of microporous specific surface area to the total specific surface area of ​​the sample. TolV is the total pore volume of the sample. mic V represents the micropore volume of the sample. mic / V Tol This represents the percentage of micropore volume to total pore volume.

[0143] Table 1

[0144]

[0145] As can be seen from Table 1, by comparing Example 1 with Examples 2-5, it can be seen that with a reasonable ratio of activator to petroleum-based raw materials and preparation process parameters, the resulting petroleum-based activated carbon has a higher specific surface area and porosity, and better adsorption performance.

[0146] A comparison of Examples 1 with Examples 6 and 7 shows that both excessively low and excessively high amounts of activator have an adverse effect on the pore structure of petroleum-based activated carbon. A comparison of Examples 1 with Examples 8 and 9 shows that excessively low or high concentrations of ferric chloride in the ferric chloride solution significantly reduce the adsorption capacity. A comparison of Examples 1 with Examples 10 and 11 shows that using potassium hydroxide in combination with other types of activators provided by this invention results in a decrease in the adsorption capacity of the obtained petroleum-based activated carbon. A comparison of Examples 1 with Examples 12-14 shows that using other types of metal salts provided by this invention to prepare metal salt solutions slightly reduces the adsorption performance of the modified activated carbon.

[0147] Comparing Example 1 with Comparative Example 1, it can be seen that the adsorption capacity of petroleum-based activated carbon without metal modification is significantly reduced, but the specific surface area and micropore area are larger. This may be because the modified metal ions occupy part of the pore space and fill the pores of the activated carbon. Comparing Example 1 with Comparative Example 2, it can be seen that the pore volume of petroleum-based activated carbon prepared with a single activator is significantly increased and the microporosity is reduced, with more mesopores. Comparing Example 1 with Comparative Example 3, it can be seen that the petroleum-based activated carbon prepared without a pre-activation step has a lower specific surface area and weaker adsorption performance. Comparing Example 1 with Comparative Example 4, it can be seen that impregnation of the petroleum-based activated carbon precursor with an unadjusted metal salt solution will cause pore blockage, resulting in a significant reduction in specific surface area and pore volume.

[0148] In summary, the method for preparing petroleum-based activated carbon of the present invention can control the pore size distribution range of petroleum-based activated carbon by introducing a composite activator, thereby giving it a high microporosity; by loading metal onto activated carbon, the adsorption capacity of the obtained petroleum-based activated carbon for adsorbates is enhanced, and the preparation process is simple and highly feasible.

[0149] The petroleum-based activated carbon of this invention has a large specific surface area, high microporosity, and excellent adsorption capacity, with a specific surface area reaching 2813 m². 2With a microporosity of up to 99% and a saturated adsorption capacity of up to 627 mg / g, it is suitable for the adsorption treatment of chlorine-containing compounds.

[0150] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing petroleum-based activated carbon for adsorbing chlorine-containing compounds, characterized in that, The preparation method includes the following steps: (1) A petroleum-based activated carbon precursor is obtained by uniformly mixing a composite activator and a petroleum-based raw material, followed by pre-activation, activation, washing and drying. The composite activator includes a first activator and a second activator in a mass ratio of (1-5):1, wherein the first activator and the second activator have different compositions. The composite activator includes a combination of at least two of potassium hydroxide, potassium chloride, potassium carbonate, potassium bicarbonate or organic potassium salts. The mass ratio of the composite activator to the petroleum-based raw material in step (1) is (3-6):1; the pre-activation step in step (1) includes: heating to 300-500℃ at a rate of 4-6℃ / min under a protective atmosphere and holding for 0.1-2h; the activation step in step (1) includes: heating to 550-1000℃ at a rate of 4-6℃ / min under a protective atmosphere and holding for 0.5-4h. (2) The petroleum-based activated carbon precursor obtained in step (1) is immersed in a metal salt solution, and after solid-liquid separation, it is dried to obtain the petroleum-based activated carbon, wherein the specific surface area of ​​the petroleum-based activated carbon is 2000-2600 m². 2 / g, with a microporosity of 90-97% and a pore size range of 0.5-1.5nm; the metal salt solution is obtained by mixing a metal salt with a solvent and adjusting the acidity, and the metal used includes any one or a combination of at least two of iron, aluminum, magnesium, zinc or yttrium.

2. The preparation method according to claim 1, characterized in that, The composite activator in step (1) includes a combination of at least two of potassium hydroxide, potassium carbonate, potassium bicarbonate, or organic potassium salts.

3. The preparation method according to claim 1, characterized in that, The organic potassium salts include C1-C16 organic potassium salts.

4. The preparation method according to claim 3, characterized in that, The organic potassium salt is potassium citrate.

5. The preparation method according to claim 1, characterized in that, The petroleum-based raw materials in step (1) include any one or a combination of at least two of petroleum coke, pitch coke, or mesophase carbon microspheres.

6. The preparation method according to claim 1, characterized in that, In step (1), the flow rate of the protective atmosphere gas used in the pre-activation process is 90-110 mL / min.

7. The preparation method according to claim 1, characterized in that, In step (1), the flow rate of the protective atmosphere gas used in the activation process is 90-110 mL / min.

8. The preparation method according to claim 1, characterized in that, The washing steps in step (1) include: the activated material is sequentially acid-washed and water-washed until the filtrate is neutral.

9. The preparation method according to claim 8, characterized in that, The acid used for pickling includes any one or a combination of at least two of nitric acid, hydrochloric acid, sulfuric acid, hypochlorous acid, or hydrogen peroxide.

10. The preparation method according to claim 8, characterized in that, The water used for the washing includes distilled water.

11. The preparation method according to claim 1, characterized in that, The drying temperature in step (1) is 100-120℃.

12. The preparation method according to claim 1, characterized in that, The drying time in step (1) is 1-12 hours.

13. The preparation method according to claim 1, characterized in that, The immersion temperature in step (2) is 20-50℃.

14. The preparation method according to claim 1, characterized in that, The soaking time in step (2) is 22-26 hours.

15. The preparation method according to claim 1, characterized in that, The drying temperature in step (2) is 100-110℃.

16. The preparation method according to claim 1, characterized in that, The drying time in step (2) is 22-26 hours.

17. The preparation method according to claim 1, characterized in that, The mass-volume ratio of the petroleum-based activated carbon precursor to the metal salt solution in step (2) is 1 g:(0.01-0.6) L.

18. The preparation method according to claim 1, characterized in that, The concentration of the metal salt in the metal salt solution in step (2) is 0.001-0.5 mol / L.

19. The preparation method according to claim 1, characterized in that, The metal salt in the metal salt solution in step (2) includes any one or a combination of at least two of the following: metal nitrate, sulfate or chloride salt.

20. The preparation method according to claim 1, characterized in that, The solvent includes deionized water.

21. The preparation method according to claim 1, characterized in that, The acid used for acid adjustment includes hydrochloric acid.

22. The preparation method according to claim 21, characterized in that, The amount of hydrochloric acid added is such that the pH value of the mixed solution is 4.5-5.

5.

23. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: (1) A composite activator with a mass ratio of (3-6):1 and a petroleum-based raw material are uniformly mixed, and then pre-activated, activated, acid-washed and washed with water until the filtrate is neutral and dried at 100-120℃ for 1-12 hours to obtain a petroleum-based activated carbon precursor. The composite activator comprises a combination of at least two of potassium hydroxide, potassium chloride, potassium carbonate, potassium bicarbonate, or organic potassium salts; the pre-activation step comprises: heating to 300-500℃ at a rate of 4-6℃ / min under a protective atmosphere and holding at that temperature for 0.1-2h; the activation step comprises: heating to 550-1000℃ at a rate of 4-6℃ / min under a protective atmosphere and holding at that temperature for 0.5-4h; in the pre-activation, the flow rate of the gas used in the protective atmosphere is 90-110mL / min; in the activation, the flow rate of the gas used in the protective atmosphere is 90-110mL / min. (2) The petroleum-based activated carbon precursor obtained in step (1) is immersed in a metal salt solution at 20-50°C for 22-26 hours. After solid-liquid separation, it is dried at 100-110°C for 22-26 hours to obtain the petroleum-based activated carbon. The mass-to-volume ratio of the petroleum-based activated carbon precursor to the metal salt solution is 1 g:(0.01-0.6) L; the metal salt solution is obtained by mixing the metal salt with a solvent and adjusting the pH; the concentration of the metal salt in the metal salt solution is 0.001-0.5 mol / L; the acid used for adjusting the pH includes hydrochloric acid; the amount of hydrochloric acid added is such that the pH of the mixed solution is 4.5-5.

5.

24. A petroleum-based activated carbon obtained by the preparation method according to any one of claims 1-23, characterized in that, The specific surface area of ​​the petroleum-based activated carbon is 2000-2600 m². 2 / g; microporosity 90-97%; pore size range 0.5-1.5nm.

25. An application of the petroleum-based activated carbon as described in claim 24, characterized in that, The petroleum-based activated carbon is used to adsorb chlorine-containing compounds.

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