Preparation method of high-temperature wet ammonia-argon mixed gas modified coconut shell activated carbon

Abstract

According to the technical scheme, the method comprises the following steps that S1, activated carbon is added into deionized water to be heated and stirred, suction filtration is carried out after stirring, then a sample is collected and dried, and activated carbon AC is obtained; S2, the sample is put into a tubular furnace, argon is introduced, and heating is carried out; s3, after the target temperature is reached, argon passes through an ammonia water solution, activated carbon is subjected to secondary activation in a high-temperature tubular furnace, and the modified activated carbon is obtained. The activated carbon is modified by adopting a high-temperature wet ammonia-argon mixed gas activation method, so that the activated carbon has a relatively large specific surface area and is high in activation efficiency and high in reaction rate; the high-temperature wet ammonia-argon mixed gas modified coconut shell activated carbon prepared by the method disclosed by the invention has a good specific surface area, and the adsorption capacity of the high-temperature wet ammonia-argon mixed gas modified coconut shell activated carbon is increased.

Description

Technical Field

[0001] This invention relates to the field of activated carbon activation and specific surface area expansion technology, and more specifically, to a method for preparing coconut shell activated carbon modified by high-temperature wet ammonia-argon mixed gas. Background Technology

[0002] Activated carbon, with its highly developed pore structure and huge specific surface area, is widely used in water treatment, air purification, food decolorization, and other fields as a highly efficient adsorbent to remove various organic pollutants, heavy metal ions, and odor molecules. Its core adsorption performance largely depends on its specific surface area—the larger the specific surface area, the more adsorption sites a unit mass of activated carbon can provide, and the higher the adsorption capacity is generally. However, commercially available activated carbon with extremely high specific surface areas (such as certain super-activated carbons or carbon prepared by specific processes) often comes with complex production processes (such as deep activation, the use of special template agents, etc.) and higher raw material costs, resulting in a significantly higher market price than conventional commercial activated carbon. This high cost limits its widespread use in some large-scale applications (such as municipal water treatment and deep industrial wastewater treatment) or cost-sensitive fields.

[0003] Therefore, we propose a method for preparing coconut shell activated carbon modified by high-temperature humid ammonia-argon mixed gas to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies, such as complex processes, high costs, and environmental pollution, as mentioned in the background section, and to propose a simple, low-cost, and environmentally friendly method for modifying coconut shell activated carbon with a high-temperature humid ammonia-argon mixture.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing coconut shell activated carbon modified by a high-temperature humid ammonia-argon mixture includes the following steps:

[0007] S1, Activated carbon pretreatment;

[0008] Coconut shell activated carbon was added to water and heated and stirred. After stirring, the mixture was filtered, and the sample was collected and dried to obtain activated carbon AC.

[0009] S2, prepared with ammonia solution;

[0010] Dilute concentrated ammonia solution with a mass concentration of 25%-28% to obtain ammonia solution, stir at room temperature to obtain ammonia solution, and pour into a gas washing bottle;

[0011] S3. Activation of coconut shell activated carbon with high-temperature humid ammonia-argon mixed gas at different temperatures;

[0012] The cleaned and dried AC was placed in a tube furnace and heated to 800℃-1100℃ at a heating rate of 5℃ / min-10℃ / min. At the target temperature, the AC was activated and modified by argon gas carrying some ammonia water for 2 hours. After cooling, the sample ACa*℃ was obtained.

[0013] S4. Activation of coconut shell activated carbon with high-temperature humid ammonia-argon mixture for different heat preservation times;

[0014] The cleaned and dried AC was sent into a tube furnace and heated to the optimal temperature in step S3 at a heating rate of 5℃ / min-10℃ / min. The AC was modified by changing the ammonia activation time. After cooling, sample ACa*℃-*h was obtained.

[0015] S5. Activation of coconut shell activated carbon with high-temperature humid ammonia-argon mixture at different ammonia concentrations;

[0016] The cleaned and dried AC was sent into a tube furnace and heated to the optimal temperature and activation time in step S4 at a heating rate of 5℃ / min-10℃ / min. The AC was modified by changing the ammonia concentration. After cooling, the sample ACa*℃-*h-*% was obtained.

[0017] In a preferred embodiment, step S1 includes: immersing a certain amount of coconut shell activated carbon with low specific surface area in deionized water, heating and stirring at 80℃-100℃ for 2 hours, filtering, and then drying.

[0018] Step S1 also includes drying the coconut shell activated carbon from step S1 at 80℃-120℃ for 6h-8h.

[0019] In a preferred embodiment, step S2 includes: preparing concentrated ammonia solution with a mass concentration of 25%-28% into dilute ammonia solution with a mass concentration of 1%-15%, and filling it into a gas washing bottle.

[0020] In a preferred embodiment, step S3 includes: sending the cleaned and dried AC into a tube furnace, heating it to 800℃-1100℃ at a heating rate of 5℃ / min-10℃ / min under an argon atmosphere, and holding it at that temperature for 2 hours under the condition of ammonia vapor.

[0021] In a preferred embodiment, step S3 further includes: argon gas is introduced in a long-in, short-out manner, with a gas flow rate of 5-50 ml / min.

[0022] In a preferred embodiment, step S4 includes: the optimal activation temperature is the optimal temperature in S3.

[0023] In a preferred embodiment, step S4 further includes: an activation time of 1-4 hours.

[0024] In a preferred embodiment, step S5 includes: modifying activated carbon by introducing ammonia water of different concentrations at the optimal temperature of S3 and the optimal heat preservation time of S4.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. This invention prepares modified activated carbon by modifying coconut shell activated carbon with a high-temperature humid ammonia-argon mixed gas, which can increase its specific surface area and is a simple activation method.

[0027] 2. The wet ammonia-argon mixed gas modification method of activated carbon in this invention improves performance through relatively simple and inexpensive subsequent modification steps, which greatly reduces the overall cost of high-performance adsorbents.

[0028] 3. The method of this invention is a modified version of the high-temperature steam activation method, which is currently the most economical and efficient modification method.

[0029] 4. The activation method in this invention is simple and easy to implement in mechanized production, which is of great significance to industrial production. Attached Figure Description

[0030] Figure 1 This is a SEM image of the activated sample in this invention.

[0031] Figure 2 This is the N2 adsorption curve of the activated sample in the BET test of this invention. Detailed Implementation

[0032] The invention will be more readily understood by referring to the following detailed description of preferred embodiments and included examples. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the definitions in this specification shall prevail.

[0033] As used herein, the terms “prepared from” and “comprising” are synonymous. The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0034] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0035] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including the ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0036] The singular form includes the plural objects of discussion unless the context clearly indicates otherwise. "Optional" or "any one" means that the matter or event described thereafter may or may not occur, and the description includes both the possibility that the event occurs and the possibility that the event does not occur.

[0037] Approximate terms used in the specification and claims to modify quantities indicate that the invention is not limited to that specific quantity, but also includes acceptable modifications close to that quantity that do not alter the relevant essential function. Correspondingly, the use of "about," "approximately," etc., to modify a numerical value means that the invention is not limited to that precise value. In some instances, approximate terms may correspond to the precision of the instrument used to measure the value. In this application's specification and claims, scope definitions can be combined and / or interchanged, unless otherwise stated, these scopes include all subscopes contained therein.

[0038] Furthermore, the indefinite articles “a” and “an” preceding the elements or components of this invention do not impose any limitation on the quantity requirement (i.e., the number of times) of the elements or components. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers to the singular form.

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings and examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0040] Reference Figure 1-2 A method for preparing coconut shell activated carbon modified by a high-temperature humid ammonia-argon mixed gas includes the following steps:

[0041] Step S1: Activated carbon pretreatment;

[0042] Coconut shell activated carbon is added to water and heated and stirred at a temperature of 80℃-100℃ for 1-3 hours. After stirring, the sample is filtered and dried at a temperature of 80℃-120℃ for 6-8 hours to obtain activated carbon AC.

[0043] Step S2: Preparation of ammonia solution;

[0044] Dilute concentrated ammonia solution with a mass concentration of 25%-28% to ammonia solution with a mass concentration of 1%-15%, stir at room temperature to obtain an ammonia solution, and put it into a gas washing bottle;

[0045] Step S3: Activate coconut shell activated carbon with a high-temperature humid ammonia-argon mixture at different temperatures;

[0046] The washed and dried activated carbon AC was fed into a tube furnace. The mass of AC was 2-4g. The temperature was increased to 800℃-1100℃ at a heating rate of 5℃ / min-10℃ / min. At the target temperature, the activated carbon AC was activated and modified by argon gas carrying some ammonia water for 2 hours. After cooling, the sample ACa*℃ was obtained. The gas introduced during heating was pure Ar.

[0047] Step S4: Activating coconut shell activated carbon with high-temperature humid ammonia-argon mixture for different heat preservation times;

[0048] The washed and dried activated carbon AC was fed into a tube furnace and heated to the optimal temperature in step S3 at a heating rate of 5℃ / min-10℃ / min. The temperature was then maintained for 1h-4h. The AC was modified by changing the activation time of ammonia water. After cooling, sample ACa*℃-*h was obtained.

[0049] Step S5: Activate coconut shell activated carbon with a high-temperature humid ammonia-argon mixture of different ammonia concentrations;

[0050] The washed and dried activated carbon AC was fed into a tube furnace and heated to the optimal temperature and activation time of step S4 at a heating rate of 5℃ / min-10℃ / min. The AC was modified by changing the ammonia concentration, which ranged from 1% to 15%. After cooling, the sample ACa*℃-*h-* was obtained.

[0051] Reference Figure 1-2 The method of the present invention also includes the following embodiments:

[0052] Example 1:

[0053] Step S1: Place 100g of coconut shell activated carbon with a particle size of 30-60 mesh into a beaker, add deionized water, heat it in a water bath to 100℃ and boil for 2 hours, filter it and dry it in an oven at 110℃ for 6 hours to obtain the sample, denoted as AC.

[0054] Step S2: Prepare 250ml of 9% dilute ammonia solution from 160ml of concentrated ammonia solution with a mass concentration of 25-28%, and put it into a gas washing bottle. Connect the argon gas pipeline with the long end in and the short end out to ensure that the gas and ammonia solution are in full contact.

[0055] Step S3: Place 2g AC into a ceramic boat and send it into a tube furnace. Heat the furnace to 1000℃ at a heating rate of 10℃ / min under an Ar atmosphere. After reaching 1000℃, convert the gas into Ar with a concentration of 9% dilute ammonia water and keep it at that temperature for 2 hours. When cooling begins, convert the furnace to a dry Ar atmosphere.

[0056] In summary, the obtained high-temperature wet ammonia-argon mixed gas modified coconut shell activated carbon has a smaller particle size and a significantly smaller mass. In the BET test, the nitrogen adsorption capacity in its N2 adsorption curve is significantly increased, and its specific surface area increases from 926 m2 / g to 1285 m2 / g.

[0057] Example 2:

[0058] Step S1: Place 100g of coconut shell activated carbon with a particle size of 30-60 mesh into a beaker, add deionized water, heat it in a water bath to 100℃ and boil for 2 hours, filter it and dry it in an oven at 110℃ for 6 hours to obtain the sample, denoted as AC.

[0059] Step S2: Prepare 250ml of 9% dilute ammonia solution from 160ml of concentrated ammonia solution with a mass concentration of 25-28%, and put it into a gas washing bottle. Connect the argon gas pipeline with the long end in and the short end out to ensure that the gas and ammonia solution are in full contact.

[0060] Step S3: Place 2g AC into a ceramic boat and send it into a tube furnace. Heat the furnace to 1000℃ at a heating rate of 10℃ / min under an Ar atmosphere. After reaching 1000℃, convert the gas into Ar with a concentration of 9% dilute ammonia water and keep it at that temperature for 3 hours. When cooling begins, convert the furnace to a dry Ar atmosphere.

[0061] In summary, the mass of the coconut shell activated carbon modified by the high-temperature wet ammonia-argon mixture was significantly reduced. In the BET test, the nitrogen adsorption amount in its N2 adsorption curve was significantly increased, and its specific surface area increased from 926 m2 / g to 1349 m2 / g.

[0062] Example 3:

[0063] Step S1: Place 100g of coconut shell activated carbon with a particle size of 30-60 mesh into a beaker, add deionized water, heat it in a water bath to 100℃ and boil for 2 hours, filter it and dry it in an oven at 110℃ for 6 hours to obtain the sample, denoted as AC.

[0064] Step S2: Prepare 250ml of dilute ammonia solution with a mass concentration of 11% from 160ml of concentrated ammonia solution with a mass concentration of 25-28%, and put it into a gas washing bottle. Connect the argon gas pipeline with the long end in and the short end out to ensure that the gas and ammonia solution are in full contact.

[0065] Step S3: Place 2g AC into a ceramic boat and send it into a tube furnace. Heat the furnace to 1000℃ at a heating rate of 10℃ / min under an Ar atmosphere. After reaching 1000℃, convert the gas into Ar with a concentration of 11% dilute ammonia water and keep it at that temperature for 3 hours. When cooling begins, convert the furnace to a dry Ar atmosphere.

[0066] In summary, the mass of the coconut shell activated carbon modified by the high-temperature wet ammonia-argon mixture was significantly reduced. In the BET test, the nitrogen adsorption amount in its N2 adsorption curve was significantly increased, and its specific surface area increased from 926 m2 / g to 1555 m2 / g.

[0067] The examples described herein are merely illustrative, intended to explain some features of the methods described herein. The appended claims are intended to claim the broadest possible scope, and the embodiments presented herein are merely illustrative of selected implementations based on combinations of all possible embodiments. Therefore, the applicant intends that the appended claims are not limited by the selection of examples illustrating the features of the invention. Some numerical ranges used in the claims also include sub-ranges within them, and variations within these ranges should be interpreted, where possible, as covered by the appended claims.

Claims

1. A method for preparing high temperature wet ammonia-argon gas modified coconut shell activated carbon, characterized in that, The method comprises the following steps: S1, pretreating the coconut shell activated carbon: comprising hydrothermal stirring, suction filtration and drying to obtain the pretreated activated carbon AC; S2, preparing an ammonia water solution with a specified concentration: diluting concentrated ammonia water into ammonia water and placing it in a gas washing device; S3, activating the coconut shell activated carbon under different temperature conditions of high-temperature wet ammonia-argon mixed gas: in a tube furnace, the activated carbon is heated to 800-1100 DEG C under an argon atmosphere, ammonia water vapor carried by argon is introduced for activation and cooling to obtain modified activated carbon ACa*℃; S4, activating the coconut shell activated carbon under different holding time conditions of high-temperature wet ammonia-argon mixed gas: under the optimal temperature condition, the activation time is adjusted for modification to obtain the sample ACa*℃-*h; S5, activating the coconut shell activated carbon under different ammonia water concentration conditions of high-temperature wet ammonia-argon mixed gas: under the optimal temperature and time conditions, the ammonia water concentration is further adjusted for modification to obtain the sample ACa*℃-*h-*%.

2. The method for preparing high-temperature wet ammonia-argon mixed gas modified coconut shell active carbon according to claim 1, characterized in that, In S1, the coconut shell activated carbon is added into water and heated and stirred, suction filtration is performed after the stirring is completed, the sample is collected and dried to obtain the activated carbon AC.

3. The method for preparing high-temperature wet ammonia-argon mixed gas modified coconut shell active carbon according to claim 2, characterized in that, In S1, the heating and stirring temperature is 80-100 DEG C, the stirring time is 1-3 h, the drying temperature is 80-120 DEG C and the drying time is 6-8 h.

4. The method for preparing high-temperature wet ammonia-argon mixed gas modified coconut shell active carbon according to claim 1, characterized in that, In S2, the concentrated ammonia water with a mass concentration of 25-28% is diluted into ammonia water, the ammonia water solution with a concentration of 1-15% is obtained after stirring at room temperature and is loaded into a gas washing bottle.

5. The method for preparing high-temperature wet ammonia-argon mixed gas modified coconut shell active carbon according to claim 1, characterized in that, In S3, the washed and dried activated carbon AC is sent into a tube furnace, the temperature is raised to 800-1100 DEG C at a temperature raising speed of 5-10 DEG C / min, the AC is modified by activation for 2 h through argon carrying part of the ammonia water at the target temperature, and the sample ACa*℃ is obtained after cooling.

6. The method for preparing high-temperature wet ammonia-argon mixed gas modified coconut shell active carbon according to claim 5, characterized in that, In S3, the temperature range is 800-1100 DEG C, the mass of the activated carbon AC is 2-4 g, and pure Ar is introduced during temperature rising.

7. The method for preparing high-temperature wet ammonia-argon mixed gas modified coconut shell active carbon according to claim 1, characterized in that, In S4, the washed and dried activated carbon AC is sent into a tube furnace, the temperature is raised to the optimal temperature of step S3 at a temperature raising speed of 5-10 DEG C / min, the AC is modified by changing the ammonia water activation time, and the sample ACa*℃-*h is obtained after cooling.

8. The method for preparing high-temperature wet ammonia-argon mixed gas modified coconut shell active carbon according to claim 7, characterized in that, In S4, the holding time is 1-4 h.

9. The method for preparing high-temperature wet ammonia-argon mixed gas modified coconut shell active carbon according to claim 1, characterized in that, The washed and dried activated carbon AC is sent into a tube furnace, the temperature is raised to the optimal temperature and optimal activation time of step S4 at a temperature raising speed of 5-10 DEG C / min, the AC is modified by changing the ammonia water concentration, the ammonia water concentration is 1-15%, and the sample ACa*℃-*h-*% is obtained after cooling.

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