Carbon-based functional materials for adsorbing / catalyzing volatile malodorous organic matters in field and application

Abstract

The present application relates to carbon-based functional materials for adsorbing / catalyzing volatile odor organic compounds (VOOCs) in the field and application thereof. Biomass and phenolic resin are uniformly mixed in proportion, doped with a certain amount of manganese and cerium, and then mixed, granulated, dried, carbonized and activated to obtain a new type of carbon-based functional material. The carbon-based functional material can realize efficient purification of VOOCs in the field through adsorption / catalysis at a relatively low temperature (50-250 DEG C).

Description

Technical fields:

[0001] This invention belongs to the field of site volatile odor organic pollutant treatment technology, specifically involving a carbon-based functional material for adsorbing / catalyzing site volatile odor organic compounds and its application, which is used in the treatment of site volatile odor organic compounds. Background technology:

[0002] Volatile odorous organic compounds (VOOCs) released during the excavation and remediation of contaminated sites can cause olfactory irritation at low concentrations (ppb), becoming an environmental hazard. During the excavation and remediation process, a canopy is typically used to collect the released VOOCs, which are then transported under negative pressure to a purification reactor for removal. The key to VOOCs purification technology lies in the purification materials.

[0003] Carbon-based functional materials, due to their large specific surface area and abundant porous structure, hold promise for developing VOOCs purification materials with both strong adsorption and rapid degradation functions through the design of active functional structures. Studies have reported that biochar materials prepared from single biomass sources such as straw, when loaded with metal active components, suffer from the problem of easy agglomeration of the metal active components, leading to sintering deactivation. However, carbon materials prepared by adding phenolic resin components are beneficial for enhancing the dispersibility of active components, thereby improving the catalytic activity of the functional materials.

[0004] Functional materials obtained by using biomass and phenolic resin as raw materials, doping with active metal components, and undergoing granulation, carbonization, and activation treatment, are expected to effectively purify site VOOCs under relatively low temperature (50-250℃) conditions. However, no relevant reports have been found to date. Summary of the Invention:

[0005] The purpose of this invention is to provide a carbon-based functional material for adsorbing / catalyzing volatile organic compounds (VOCs) in a site and its application. Biomass and phenolic resin are uniformly mixed in a certain proportion, with a certain amount of manganese and cerium added. After mixing, granulation, drying, carbonization, and activation, a novel carbon-based functional material is obtained. This material can effectively purify VOOCs in a site through adsorption / catalysis at relatively low temperatures (50-250℃), effectively preventing odor penetration.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A carbon-based functional material for adsorbing / catalyzing volatile organic compounds from a site is disclosed. The material is prepared by uniformly mixing biomass and phenolic resin, and doping with manganese and cerium. The process involves mixing, granulation, drying, carbonization, and activation. The mass percentages of the components are: biomass 30-70 wt%, phenolic resin 30-60 wt%, and the total loading of manganese and cerium is 1-10 wt%, with a manganese / cerium molar ratio of 0.5:1 to 4:1.

[0008] The carbonization temperature is 300-600℃; the activation temperature is 600-950℃; the activation atmosphere is an atmosphere with N2 as the carrier gas and CO2 with a volume content of 5-15%.

[0009] The biomass is one or more of the following: corn stalks, wheat stalks, rice stalks, sugarcane bagasse, cotton stalks, etc.; preferably, the particle size of the biomass is 80-160 μm.

[0010] The preparation method of the above-mentioned carbon-based functional material for adsorbing / catalyzing volatile odorous organic compounds in the above-mentioned environment, wherein the specific steps of the preparation method are as follows:

[0011] Step 1, Mixing: Crush the biomass through an 80-150 mesh sieve, mix it evenly with a certain amount of phenolic resin, add it to a certain amount of mixed solution containing manganese salt and cerium salt, stir for 30-120 minutes, and dry at 80-100℃.

[0012] Step 2, Granulation: Granulate the material from Step 1 under a pressure of 1-10 MPa to obtain cylindrical samples with a diameter of 4-8 mm and a length of 5-12 mm.

[0013] Step 3, Drying: Place the cylindrical sample prepared in step 2 in an oven and dry for 4-12 hours at a temperature of 50-100℃.

[0014] Step 4, carbonization: The dried cylindrical sample is heated to 300-600℃ at a rate of 2-10℃ / min under N2 atmosphere and carbonized for 30-90min.

[0015] Step 5, Activation: Under a N2 atmosphere, heat to 600-950℃ at a rate of 5-15℃ / min, using N2 as the carrier gas, and introduce CO2 with a volume content of 5-15% for 30-90 min to prepare a carbon-based functional material for adsorbing / catalyzing volatile odorous organic compounds from the site. Excessive activation time can easily lead to a decrease in strength and poor purification activity.

[0016] The manganese salt is at least one of manganese chloride, manganese nitrate, manganese sulfate, potassium permanganate, etc.

[0017] The cerium salt is at least one of cerium chloride, cerium nitrate, cerium sulfate, cerium sulfate, etc.

[0018] The application conditions for the above-mentioned carbon-based functional materials for adsorbing / catalyzing volatile organic compounds (VOCs) in the site are as follows: VOCs are collected under a canopy and transported under negative pressure to a purification reactor for removal; the adsorption / catalytic reaction temperature is 50-250℃; the VOOCs concentration is 50-500ppm; the O2 volume content is 5-30%; and the mass hourly space velocity (WHSV) is 3600-72000 mL (g / g). -1 ·h -1 ).

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] The carbon-based functional material prepared by this invention has higher purification efficiency than commercial vanadium-tungsten-titanium catalysts, and the purified exhaust gas is odorless, which can effectively prevent malodor penetration (see Table 1).

[0021] Table 1 Comparison of Performance Indicators of Carbon-Based Functional Materials

[0022]

[0023] Experimental conditions: reaction temperature 250℃, toluene concentration (a representative VOOC compound) 60 ppm, O2 volume content 10%, mass hourly space velocity (WHSV) 36000 mL (g) -1 ·h -1 ).

[0024] In this invention, phenolic resin synergistically interacts with biomass and active components during carbonization and activation, effectively regulating the composition and structure of the carrier, the valence state of the metal active components, and their dispersibility, thereby controlling the adsorption and catalytic performance of the material. By controlling the ratio of biomass, phenolic resin, and manganese and cerium salts, as well as the carbonization and activation temperatures and times, carbon-based functional materials with high mechanical strength and good purification efficiency can be obtained. Experimental results show that the carbon-based functional materials prepared in this invention achieve a site VOOCs removal rate >99% within the temperature range of 200-250℃, effectively preventing odor penetration, with a compressive strength of 350-550N and an abrasion resistance of 90%-99%. Detailed implementation method:

[0025] To better understand the content of this invention, the following description, in conjunction with embodiments, further illustrates the invention. However, the examples given do not limit the scope of protection of this invention.

[0026] Example 1

[0027] (1) Carbon-based functional materials for adsorbing / catalyzing volatile organic compounds (VOOCs) from a site. The preparation steps of this carbon-based functional material are as follows:

[0028] Step 1, Mixing: Crush corn stalks and pass them through an 80-mesh sieve. Weigh 55 wt% of corn stalks and mix them evenly with 45 wt% of phenolic resin. Add this mixture to a mixed solution of manganese nitrate and cerium nitrate with a manganese / cerium molar ratio of 3:1. Stir for 60 minutes and dry at 80°C. The total loading of manganese and cerium is 3 wt%.

[0029] Step 2, Granulation: The mixed material is granulated under a pressure of 3MPa to obtain a cylindrical sample with a diameter of 5mm and a length of 7mm;

[0030] Step 3, Drying: Place the cylindrical sample prepared in step 2 in an oven and dry for 8 hours at a temperature of 80°C.

[0031] Step 4, carbonization: The dried cylindrical sample is heated to 400℃ at a rate of 5℃ / min under N2 atmosphere and carbonized for 60min.

[0032] Step 5, Activation: Under N2 atmosphere, heat to 800℃ at a rate of 10℃ / min, use N2 as carrier gas, introduce CO2 with a content of 10%, and activate for 60min.

[0033] (2) Adsorption / catalytic performance of carbon-based functional materials for site VOOCs

[0034] The experimental conditions for evaluating the adsorption / catalytic performance of carbon-based functional materials on toluene, a representative compound of hydrocarbon site-emitted VOOCs, were as follows: site-emitted VOOCs were collected under a canopy and transported under negative pressure to a purification reactor; the reaction temperature was 50-250℃; the toluene concentration was 60 ppm; the O2 volume content was 10%; and the mass hourly space velocity (WHSV) was 36000 mL / g. -1 ·h -1 The toluene content in the tail gas after the reaction was detected by gas chromatography, and the toluene removal rate was calculated. The odor intensity was determined according to the "Three-point Comparison Odor Bag Method" (GB / T 14675-93). The compressive strength and abrasion resistance of the carbon-based functional materials were tested using a compressive strength tester and an abrasion resistance tester, respectively. The results are shown in Table 2.

[0035] Table 3. Toluene removal rate, exhaust gas odor intensity, and pressure and abrasion resistance values ​​of carbon-based functional materials.

[0036]

[0037] Example 2

[0038] (1) The carbon-based functional material for adsorbing / catalyzing VOOCs in this embodiment uses the same raw materials and preparation process as in Example 1. The difference is that the mixing conditions in this embodiment are as follows: corn stalks are weighed and mixed evenly with phenolic resin, then added to a mixed solution of manganese nitrate and cerium nitrate with a manganese / cerium molar ratio of 1.5:1, stirred for 60 min, and dried at 80°C. The total loading of manganese and cerium is 2 wt%.

[0039] (2) Adsorption / catalytic performance of carbon-based functional materials for site VOOCs

[0040] The experimental conditions for evaluating the adsorption / catalytic performance of carbon-based functional materials on methanethiol, a representative compound of VOOCs from sulfur-containing sites, were as follows: VOOCs escaping from the site were collected under a canopy and transported under negative pressure to a purification reactor; the reaction temperature was 50-250℃; the methanethiol concentration was 60 ppm; the O2 volume content was 10%; and the mass hourly space velocity (WHSV) was 36000 mL / g. -1 ·h -1 The content of methanethiol in the tail gas after the reaction was detected by gas chromatography, and the methanethiol removal rate was calculated. The odor intensity was determined according to the "Three-point Comparison Odor Bag Method" (GB / T 14675-93). The compressive strength and abrasion resistance of the carbon-based functional materials were tested using a compressive strength tester and an abrasion resistance tester, respectively. The results are shown in Table 3.

[0041] Table 3. Removal rate of methanethiol, odor intensity of exhaust gas, and pressure and abrasion resistance values ​​of carbon-based functional materials.

[0042]

[0043] Example 3

[0044] (1) The carbon-based functional material for adsorbing / catalyzing VOOCs in this embodiment is the same as that in Example 1 in terms of raw materials and preparation process. The difference is that the mixing conditions in this embodiment are: weigh 60wt% corn straw and mix 40wt% phenolic resin evenly.

[0045] (2) Adsorption / catalytic performance of carbon-based functional materials for site VOOCs

[0046] The experimental conditions for evaluating the adsorption / catalytic performance of carbon-based functional materials on methylamine, a representative compound of nitrogen-containing VOOCs from nitrogen-containing sites, were as follows: VOOCs escaping from the site were collected under a canopy and transported under negative pressure to a purification reactor; the reaction temperature was 50-250℃; the methylamine concentration was 60 ppm; the O2 volume content was 10%; and the mass hourly space velocity (WHSV) was 36000 mL / g. -1 ·h -1The methylamine content in the tail gas after the reaction was detected by gas chromatography, and the methylamine removal rate was calculated. The odor intensity was determined according to the "Three-point Comparison Odor Bag Method" (GB / T 14675-93). The compressive strength and abrasion resistance of the carbon-based functional materials were tested using a compressive strength tester and an abrasion resistance tester, respectively. The results are shown in Table 4.

[0047] Table 4. Removal rate of methylamine, exhaust odor intensity, and pressure and abrasion resistance values ​​of carbon-based functional materials.

[0048]

[0049] Example 4

[0050] (1) The carbon-based functional material for adsorbing / catalyzing VOOCs in this embodiment is the same as that in Example 1 in terms of raw materials and preparation process. The difference is that the carbonization conditions in this embodiment are: the temperature is increased to 600℃ at a rate of 5℃ / min and carbonized for 30min.

[0051] (2) Adsorption / catalytic performance of carbon-based functional materials for site VOOCs

[0052] The experimental conditions for evaluating the adsorption / catalytic performance of carbon-based functional materials on trichloroethylene, a representative compound of VOOCs from chlorine-containing sites, were as follows: VOOCs escaping from the site were collected under a canopy and transported under negative pressure to a purification reactor; the reaction temperature was 50-250℃; the trichloroethylene concentration was 60 ppm; the O2 volume content was 10%; and the mass hourly space velocity (MSV) was 36000 mL / g. -1 ·h -1 The trichloroethylene content in the tail gas after the reaction was detected by gas chromatography, and the trichloroethylene removal rate was calculated. The odor intensity was determined according to the "Three-point Comparison Odor Bag Method" (GB / T14675-93). The compressive strength and abrasion resistance of the carbon-based functional materials were tested using a compressive strength tester and an abrasion resistance tester, respectively. The results are shown in Table 5.

[0053] Table 5. Removal rate of trichloroethylene, exhaust gas odor intensity, and pressure and abrasion resistance values ​​of carbon-based functional materials.

[0054]

[0055] Comparative Example 1

[0056] Only the biomass, manganese salt, and cerium salt described in Example 1 of this application are added, and the mixture is processed according to the mixing, granulation, drying, carbonization, and activation conditions of Example 1.

[0057] Comparative Example 2

[0058] Asphalt (a macromolecular organic compound) was added to replace the phenolic resin in this application, and the mixture was processed according to the mixing, granulation, drying, carbonization, and activation conditions of Example 1.

[0059] Comparative Example 3

[0060] Iron salts were added to replace the manganese and cerium salts in this application, and the mixture was processed according to the mixing, granulation, drying, carbonization, and activation conditions of Example 1.

[0061] Comparative Example 4

[0062] Only the biomass and phenolic resin described in this application are added, and the mixture is processed according to the mixing, granulation, drying, carbonization, and activation conditions of Example 1.

[0063] Comparative Example 5

[0064] Only one type of commercial granular activated carbon was used.

[0065] Comparative Example 6

[0066] Only one commercial vanadium-tungsten-titanium catalyst is used.

[0067] The adsorbent materials obtained in Comparative Examples 1-6 were all tested under the site VOOCs purification experimental conditions of Example 1. The toluene removal rate results are shown in Table 6, the exhaust gas odor intensity results are shown in Table 7, and the intensity values ​​are shown in Table 8.

[0068] Table 6 compares the toluene removal rates of the comparative examples and Example 1.

[0069]

[0070] Table 7 Comparison of exhaust odor intensity between the comparative example and Example 1

[0071]

[0072] Sensory description: 0 - Odorless, 1 - Odor is faint, 2 - Odor is faint but can be identified, 3 - Odor can be clearly perceived, 4 - Odor is relatively strong.

[0073] Table 8 Comparison of strength values ​​between the comparative example and Example 1

[0074]

[0075] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A carbon-based functional material for adsorbing / catalyzing volatile odorous organic compounds from a site, characterized in that, Biomass and phenolic resin are uniformly mixed, and the metal elements manganese and cerium are doped. After mixing, granulation, drying, carbonization and activation, carbon-based functional materials are obtained. The mass percentage of each component is: biomass 30-70 wt%, phenolic resin 30-60 wt%; the total loading of manganese and cerium is 1-10 wt%, and the manganese / cerium molar ratio is 0.5:1~4:

1. The carbonization temperature is 300-600℃; the activation temperature is 600-950℃; the activation atmosphere is an atmosphere with N2 as the carrier gas and CO2 with a volume content of 5-15% introduced. The mixing process is as follows: the biomass is crushed and passed through an 80-150 mesh sieve, the biomass and phenolic resin are mixed evenly in proportion, added to a mixed solution containing manganese salt and cerium salt, stirred for 30-120 min, and dried at 80-100℃. The mixed material is granulated under a pressure of 1-10 MPa. The biomass is one or more of the following: corn stalks, wheat stalks, rice stalks, sugarcane bagasse, or cotton stalks; The carbon-based functional material has a site VOOCs removal rate of >99% within a temperature range of 200-250℃, and the odor intensity is 0 when measured according to GB / T 14675-93 "Three-point comparison odor bag method", effectively preventing malodor penetration, and the compressive strength is 350-550 N.

2. The carbon-based functional material for adsorbing / catalyzing volatile organic compounds in a site according to claim 1, characterized in that, The biomass has a particle size of 80-160 micrometers.

3. The carbon-based functional material for adsorbing / catalyzing volatile organic compounds in a site according to claim 1, characterized in that, The metal element manganese is introduced in at least one of manganese chloride, manganese nitrate, manganese sulfate, or potassium permanganate; the metal element cerium is introduced in at least one of cerium chloride, cerium nitrate, cerium sulfate, or cerium sulfate.

4. The carbon-based functional material for adsorbing / catalyzing volatile organic compounds in a site according to claim 1, characterized in that, The preparation steps of the carbon-based functional material are as follows: Step 1, Mixing: Crush the biomass through an 80-150 mesh sieve, mix the biomass and phenolic resin in a uniform ratio, add it to a mixed solution containing manganese salt and cerium salt, stir for 30-120 min, and dry at 80-100℃. Step 2, Granulation: Granulate the material from Step 1 under a pressure of 1-10 MPa to obtain cylindrical samples with a diameter of 4-8 mm and a length of 5-12 mm. Step 3, Drying: Place the cylindrical sample prepared in step 2 in an oven and dry for 4-12 hours at a temperature of 50-100℃. Step 4, carbonization: The dried cylindrical sample is heated to 300-600℃ at a rate of 2-10℃ / min under N2 atmosphere and carbonized for 30-90 min. Step 5, Activation: Under N2 atmosphere, heat to 600-950℃ at a rate of 5-15℃ / min, use N2 as carrier gas, introduce CO2 with a volume content of 5-15%, and activate for 30-90min to prepare carbon-based functional materials that adsorb / catalyze volatile odorous organic compounds from the site.

5. The application of a carbon-based functional material for adsorbing / catalyzing volatile odorous organic compounds in a site, as described in any one of claims 1-4, characterized in that... VOOCs are collected under a canopy and transported under negative pressure to a purification reactor for removal. The adsorption / catalytic reaction temperature is 50-250℃, the VOOCs concentration is 50-500 ppm, the O2 volume content is 5-30%, and the mass hourly space velocity is 3600-72000 mL (g). -1 h -1 ).

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