Porous carbon / ceramic composite functional material for removing odor organic pollutants in sites

Abstract

The present application relates to a kind of porous carbon / ceramic composite functional materials for removing site odor organic pollutants.Industrial solid waste iron tailings, bentonite, forestry solid waste source biomass are used as raw materials, and through mixing-granulation-impregnation-drying-calcination process, the porous carbon / ceramic composite functional material with high mechanical strength and loaded with manganese and samarium double active components is prepared.The functional material can efficiently remove site odor organic pollutants at 300-350 DEG C, and the tail gas after purification has no odor.

Description

Technical fields:

[0001] This invention belongs to the field of site odor organic pollutant treatment technology, specifically relating to a porous carbon / ceramic composite functional material for removing site odor organic pollutants. The porous carbon / ceramic composite functional material is used to purify site odor organic pollutants. Background technology:

[0002] Typical odor-contaminated sites from industries such as chemical manufacturing, pharmaceutical production, and landfills release odorous organic pollutants during excavation and remediation. These pollutants not only pose environmental hazards but can also cause olfactory irritation at low concentrations (ppb), making remediation technology a hot research topic. Currently, odorous organic pollutants released from these sites can be collected under a canopy and transported under negative pressure to a remediation reactor for removal. The key to the removal efficiency lies in the remediation materials. Recent studies have shown that coupling the adsorption and catalytic oxidation functions of materials yields better remediation results for odorous organic pollutants.

[0003] The key to adsorption / catalytic oxidation functional materials lies in the assembly design of carrier materials with broad-spectrum adsorption properties and active components for the efficient catalytic oxidation of odorous organic pollutants. Studies have reported that natural clays such as bentonite and industrial solid wastes such as iron tailings can be used as inexpensive raw materials to prepare carriers with certain mechanical strength. Loading these carriers with active components yields functional materials for the catalytic oxidation of odorous organic pollutants. However, their purification efficiency is poor below 350℃, and the purified exhaust gas still retains an odor. Research indicates that carbon-based functional materials, due to their large specific surface area and abundant pore structure, can improve the purification efficiency of odorous organic pollutants through adsorption. However, single carbon-based materials only possess adsorption capabilities and their purification performance for odorous gases is unsatisfactory.

[0004] This invention uses industrial solid waste iron tailings, bentonite, and agricultural and forestry solid waste biomass as raw materials, and loads manganese and samarium active components to prepare a novel porous carbon / ceramic composite functional material with high mechanical strength. It can purify site odor organic pollutants through adsorption / catalysis, effectively solving the odor problem after purification. No related research has been reported. Summary of the Invention:

[0005] The purpose of this invention is to provide a porous carbon / ceramic composite functional material for removing odorous organic pollutants from sites. This porous carbon / ceramic composite functional material uses industrial solid waste iron tailings as a carrier material, bentonite as a binder, and agricultural and forestry solid waste-derived biomass as a pore-forming agent. After granulation and pore formation, it is loaded with manganese / samarium dual active components via impregnation, and then dried and calcined. Its compressive strength is 420–500 N, and its abrasion resistance is 90%–99%. It can efficiently remove odorous organic pollutants from sites at 300–350℃.

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

[0007] A porous carbon / ceramic composite functional material for removing odorous organic pollutants from a site is prepared by using industrial solid waste iron tailings as a carrier material, bentonite as a binder, and agricultural and forestry solid waste biomass as a pore-forming agent. After granulation and calcination in an air atmosphere, a porous carbon / ceramic carrier is obtained. The porous carbon / ceramic carrier is then impregnated in a mixed solution containing manganese salt and samarium salt, and manganese / samarium dual active components are loaded by impregnation. After drying and calcination, the porous carbon / ceramic composite functional material is obtained.

[0008] The calcination temperature in the air atmosphere is 500–950°C, preferably 600–800°C, and the calcination time in the air atmosphere is 30–90 min.

[0009] The roasting temperature during drying and roasting is 300–500℃, preferably 300–450℃, and the roasting atmosphere is N2.

[0010] The mass percentages of each component in the raw materials of the porous carbon / ceramic composite functional material are as follows: 30-60 wt% iron tailings, 30-60 wt% bentonite, 5-15 wt% agricultural and forestry solid waste biomass, and 5-20 wt% total manganese / samarium loading, wherein the manganese / samarium molar ratio is 1:1 to 9:1, and the total manganese / samarium loading refers to the percentage of the mass of manganese and samarium in the total mass of the functional material.

[0011] The agricultural and forestry solid waste source biomass is one or more of the following: corn stalks, wheat stalks, rice stalks, sugarcane bagasse, cotton stalks, coconut shells, and fruit shells; the manganese salt is at least one of the following: manganese chloride, manganese nitrate, manganese sulfate, and potassium permanganate; and the samarium salt is at least one of the following: samarium chloride, samarium nitrate, samarium sulfate, and samarium acetate.

[0012] The specific preparation process of the aforementioned porous carbon / ceramic composite functional material for removing site odors and organic pollutants is as follows:

[0013] Step 1, Mixing: Crush iron tailings, bentonite, and agricultural and forestry solid waste biomass through an 80-120 mesh sieve. Weigh the iron tailings, bentonite, and agricultural and forestry solid waste biomass and mix them evenly. Add water and stir evenly at a rate of 60-120 r / min for 2-5 min. The amount of water added is 5-20 wt% of the total mass of iron tailings, bentonite, and agricultural and forestry solid waste biomass.

[0014] Step 2, Granulation: Place the material obtained in Step 1 in a disc granulator and granulate it at a speed of 30-80 r / min to obtain pellets with a diameter of 5-30 mm; after drying, heat the pellets to 500-950℃ at a rate of 5-10℃ / min and calcine them in air atmosphere for 30-90 min to obtain porous carbon / ceramic carrier.

[0015] Step 3, Impregnation: The porous carbon / ceramic support obtained in step 2 is impregnated in a mixed solution of manganese salt and samarium salt for 30 to 90 minutes;

[0016] Step 4, Drying: Dry the sample obtained in step 3 at 60-100℃ to constant weight;

[0017] Step 5, calcination: Under a nitrogen atmosphere, the temperature is increased to 300-500℃ at a rate of 5-10℃ / min, and calcined for 1-3 hours to obtain porous carbon / ceramic composite functional materials.

[0018] The application conditions for the porous carbon / ceramic composite functional material for removing site odor organic pollutants are as follows: odorous gases are collected under a canopy and transported under negative pressure to a purification reactor to remove odor organic pollutants; the reaction temperature is 50–350℃; the concentration of odor organic pollutants is 50–500 ppm; the O2 content is 5–30%; and the mass hourly space velocity is 3600–72000 mL (g). -1 ·h -1 ).

[0019] The site odor organic pollutants include hydrocarbons and volatile organic compounds containing sulfur, nitrogen, chlorine, and oxygen, preferably toluene, methanethiol, methylamine, trichloroethylene, etc.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] The porous carbon / ceramic 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 odor penetration (see Table 1).

[0022] Table 1 Comparison of Performance Indicators of Porous Carbon / Ceramic Functional Materials

[0023]

[0024] Experimental conditions: reaction temperature 350℃, toluene concentration (a representative organic pollutant of hydrocarbon sites) 60 ppm, O2 volume content 10%, mass hourly space velocity (WHSV) 36000 mL (g) -1 ·h -1 ).

[0025] The pellets used in the granulation process of this invention need to be calcined in an air atmosphere for a period of time to obtain a porous carbon / ceramic carrier with high strength. After that, impregnation and calcination are carried out to effectively adjust the valence state of the active components on the carrier, so that the functional material can achieve excellent odor purification effect. According to the "Three-point Comparison Odor Bag Method" (GB / T 14675-93), the exhaust gas was found to be odorless. Detailed implementation method:

[0026] 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.

[0027] Example 1

[0028] (1) A porous carbon / ceramic composite functional material for removing organic pollutants and odors from a site (hereinafter referred to as porous carbon / ceramic composite functional material). The preparation steps of the porous carbon / ceramic composite functional material are as follows:

[0029] Step 1, Mixing: Crush iron tailings, bentonite and corn stalks through an 80-mesh sieve. Weigh 40wt% iron tailings, 50wt% bentonite and 10wt% corn stalks and mix them evenly. Add 15wt% water and stir at 100r / min for 3min.

[0030] Step 2, Granulation: Place the material obtained in Step 1 in a disc granulator and granulate it at a speed of 50 r / min to obtain material balls with a diameter of 5 mm; after drying, heat the material balls to 800℃ at a rate of 10℃ / min and calcine them in air atmosphere for 60 min to obtain porous carbon / ceramic carrier.

[0031] Step 3, Impregnation: The porous carbon / ceramic support from Step 2 is impregnated in a mixed solution of manganese nitrate and samarium nitrate with a manganese / samarium molar ratio of 3:1 for 60 min, wherein the total manganese / samarium loading is 15 wt%.

[0032] Step 4, Drying: Dry the sample prepared in step 3 at 80℃ to constant weight;

[0033] Step 5, calcination: Heat to 400℃ at a rate of 10℃ / min and calcine in a nitrogen atmosphere for 1 hour to obtain porous carbon / ceramic composite functional material.

[0034] (2) Purification performance of porous carbon / ceramic composite functional materials for site odor organic pollutants

[0035] The experimental conditions for evaluating the performance of porous carbon / ceramic composite materials in purifying toluene, a representative compound of hydrocarbon-based organic pollutants causing odors in polluted sites, were as follows: odorous gases were collected under a canopy and transported under negative pressure to the purification reactor; the reaction temperature was 50–350 °C; 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 -1The toluene content in the tail gas after the reaction was detected by gas chromatography, and the toluene removal rate was calculated. The compressive strength and abrasion resistance of the porous carbon / ceramic composite functional material were tested using a compressive strength tester and an abrasion resistance tester, respectively. The results are shown in Table 2. Under the condition of 300-350℃, the toluene removal rate was >99%, and the purified tail gas was found to be odorless according to the "Three-Point Comparison Odor Bag Method" (GB / T 14675-93).

[0036] Table 2. Toluene removal rate and pressure and abrasion resistance values ​​of porous carbon / ceramic composite functional materials.

[0037]

[0038] Example 2

[0039] (1) The porous carbon / ceramic composite functional material for removing site odors and organic pollutants in this embodiment is the same as that in Example 1. The difference is that the mixing conditions in this embodiment are: weigh 35wt% iron tailings, 45wt% bentonite and 20wt% corn straw and mix them evenly.

[0040] (2) Purification performance of porous carbon / ceramic composite functional materials for site odor organic pollutants

[0041] The experimental conditions for evaluating the performance of porous carbon / ceramic composite materials in purifying methanethiol, a representative compound of organic pollutants causing odors in sulfur-containing sites, were as follows: odorous gases were collected under a canopy and transported under negative pressure to the purification reactor; the reaction temperature was 50–350 °C; the methanethiol 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 methanethiol content in the tail gas after the reaction was detected by gas chromatography, and the methanethiol removal rate was calculated. The compressive strength and abrasion resistance of the porous carbon / ceramic composite functional material were tested using a compressive strength tester and an abrasion resistance tester, respectively. The results are shown in Table 3. Under the condition of 300-350℃, the methanethiol removal rate was >99%, and the tail gas was found to be odorless according to the "Three-Point Comparison Odor Bag Method" (GB / T 14675-93).

[0042] Table 3. Removal rate of methanethiol and compressive and abrasion resistance values ​​of porous carbon / ceramic composite functional materials.

[0043]

[0044] Example 3

[0045] (1) The porous carbon / ceramic composite functional material for removing site odor organic pollutants in this embodiment is the same as that in Example 1 in terms of raw materials and preparation process. The difference is that the granulation conditions in this embodiment are: after the material balls are dried, the temperature is raised to 600°C at a rate of 10°C / min and calcined in air atmosphere for 40 min to obtain porous carbon / ceramic carrier.

[0046] (2) Purification performance of porous carbon / ceramic composite functional materials for site odor organic pollutants

[0047] The experimental conditions for evaluating the performance of porous carbon / ceramic composite materials in purifying methylamine, a representative compound of nitrogen-containing organic pollutants causing odors in nitrogen-containing sites, were set as follows: odorous gases were collected under a canopy and transported under negative pressure to the purification reactor; the reaction temperature was 50–350 °C; 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 -1 The methylamine content in the tail gas after the reaction was detected by gas chromatography, and the methylamine removal rate was calculated. The compressive strength and abrasion resistance of the porous carbon / ceramic composite functional material were tested using a compressive strength tester and an abrasion resistance tester, respectively. The results are shown in Table 4. Under the condition of 300-350℃, the methylamine removal rate was >99%, and the tail gas was found to be odorless according to the "Three-Point Comparison Odor Bag Method" (GB / T 14675-93).

[0048] Table 4. Removal rate of methylamine and compressive strength and abrasion resistance values ​​of porous carbon / ceramic composite functional materials.

[0049]

[0050] Example 4

[0051] (1) The porous carbon / ceramic composite functional material for removing site odor organic pollutants in this embodiment has the same raw materials and preparation process as in Example 1. The difference is that the impregnation conditions in this embodiment are: the porous carbon / ceramic carrier is impregnated in a mixed solution of manganese nitrate and samarium nitrate with a manganese / samarium molar ratio of 9:1 for 40 min, and the total manganese / samarium loading is 10 wt%.

[0052] (2) Purification performance of porous carbon / ceramic composite functional materials for site odor organic pollutants

[0053] The experimental conditions for evaluating the performance of porous carbon / ceramic composite materials in purifying trichloroethylene, a representative compound of organic pollutants causing odor in chlorine-containing sites, were as follows: odorous gases were collected under a canopy and transported under negative pressure to the purification reactor; the reaction temperature was 50–350 °C; 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 -1The trichloroethylene content in the exhaust gas after the reaction was detected by gas chromatography, and the trichloroethylene removal rate was calculated. The compressive strength and abrasion resistance of the porous carbon / ceramic composite functional material were tested using a compressive strength tester and an abrasion resistance tester, respectively. The results are shown in Table 5. At 350℃, the trichloroethylene removal rate was >99%, and the exhaust gas was found to be odorless according to the "Three-Point Comparison Odor Bag Method" (GB / T 14675-93).

[0054] Table 5. Removal rate of trichloroethylene and compressive and abrasion resistance values ​​of porous carbon / ceramic composite functional materials.

[0055]

[0056] Comparative Example 1

[0057] Only iron tailings, agricultural and forestry solid waste biomass, manganese salt, and samarium salt as described in Example 1 of this application are added, and the mixture is processed according to the mixing, granulation, drying, impregnation, and roasting conditions of Example 1.

[0058] Comparative Example 2

[0059] Only the iron tailings, agricultural and forestry solid waste biomass, and bentonite described in this application are added, and the mixture is processed according to the mixing, granulation, drying, impregnation, and roasting conditions of Example 1.

[0060] Comparative Example 3

[0061] Only attapulgite was added to replace bentonite, and the mixture was processed according to the mixing, granulation, drying, impregnation, and calcination conditions of Example 1.

[0062] Comparative Example 4

[0063] Only one type of commercial granular activated carbon was used.

[0064] Comparative Example 5

[0065] Only one commercial vanadium-tungsten-titanium catalyst is used.

[0066] The functional materials obtained in Comparative Examples 1 to 5 were all tested under the site odor organic pollutant purification experimental conditions of Example 1. The toluene removal rate results are shown in Table 7, and the intensity results are shown in Table 8. Under the condition of 300-350℃, the odor intensity was measured according to the "Three-Point Comparison Odor Bag Method" (GB / T 14675-93). It was found that the exhaust gas purified by the comparative materials still had an odor, while the exhaust gas purified by the porous carbon / ceramic composite functional material prepared in this invention had no odor.

[0067] Table 7 Comparison of toluene removal rates between the comparative example and Example 1

[0068]

[0069] Table 8 Comparison of strength values ​​between the comparative example and Example 1

[0070]

[0071] The results in the table above show that the porous carbon / ceramic composite functional material prepared by this invention has an excellent removal rate of organic pollutants causing odors in the site compared with other purification functional materials. In particular, under the condition of 350℃, the removal rate of organic pollutants causing odors in the site is >99%, the purified exhaust gas is odorless, and it also has high mechanical strength.

[0072] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A porous carbon / ceramic composite functional material for removing odorous organic pollutants from a site, characterized in that: Using industrial solid waste iron tailings as carrier material, bentonite as binder, and agricultural and forestry solid waste biomass as pore-forming agent, porous carbon / ceramic carriers are obtained by granulation and calcination in air atmosphere. The porous carbon / ceramic carriers are then impregnated in a mixed solution containing manganese salt and samarium salt, and manganese / samarium dual active components are loaded by impregnation method. After drying and calcination, porous carbon / ceramic composite functional materials are prepared. The mass percentages of each component in the raw materials of the porous carbon / ceramic composite functional material are as follows: iron tailings 30-60 wt%, bentonite 30-60 wt%, agricultural and forestry solid waste biomass 5-15 wt%, and manganese / samarium total loading 5-20 wt%, wherein the manganese / samarium molar ratio is 1:1 to 9:1; the manganese / samarium total loading refers to the percentage of the mass of manganese and samarium in the total mass of the functional material; The calcination temperature in the air atmosphere is 500~950℃, and the calcination time in the air atmosphere is 30~90 min; The porous carbon / ceramic composite functional material has a compressive strength of 420~500 N and an abrasion resistance of 90%~97%. The porous carbon / ceramic composite functional material is used to remove odorous organic pollutants from the site. After the reaction, the intensity of the exhaust gas odor is evaluated according to the sensory description of the "Three-Point Comparison Odor Bag Method". Under the condition of 300~350℃, the purified exhaust gas has no odor. The site odor organic pollutant is at least one of toluene, methanethiol, methylamine, or trichloroethylene.

2. The porous carbon / ceramic composite functional material for removing odorous organic pollutants from a site according to claim 1, characterized in that: The agricultural and forestry solid waste source biomass is one or more of the following: corn stalks, wheat stalks, rice stalks, sugarcane bagasse, cotton stalks, coconut shells, or fruit shells. The manganese salt is at least one of manganese chloride, manganese nitrate, manganese sulfate, or potassium permanganate; The samarium salt is at least one of samarium chloride, samarium nitrate, samarium sulfate, or samarium acetate.

3. The porous carbon / ceramic composite functional material for removing odorous organic pollutants from a site according to claim 1, characterized in that: The roasting temperature during drying and roasting is 300-500℃, and the roasting atmosphere is N2.

4. The porous carbon / ceramic composite functional material for removing odorous organic pollutants from a site according to claim 1, characterized in that: The specific preparation steps for the porous carbon / ceramic composite functional material are as follows: Step 1, Mixing: Crush iron tailings, bentonite, and agricultural and forestry solid waste biomass through an 80-120 mesh sieve. Weigh out the iron tailings, bentonite, and agricultural and forestry solid waste biomass, mix them evenly, add water, and stir evenly at a rate of 60-120 r / min; the amount of water added is 5-20 wt% of the total mass of the iron tailings, bentonite, and agricultural and forestry solid waste biomass. Step 2, Granulation: Place the material obtained in Step 1 in a disc granulator and granulate it at a speed of 30~80 r / min to obtain pellets with a diameter of 5~30 mm; after drying, heat the pellets to 500~950℃ at a rate of 5~10℃ / min and calcine them in air atmosphere for 30~90 min to obtain porous carbon / ceramic carrier. Step 3, Impregnation: The porous carbon / ceramic support obtained in step 2 is impregnated in a mixed solution of manganese salt and samarium salt for 30 to 90 minutes. Step 4, Drying: Dry the sample obtained in step 3 at 60~100℃ to constant weight; Step 5, calcination: Under a nitrogen atmosphere, the temperature is increased to 300-500℃ at a rate of 5-10℃ / min, and calcined for 1-3 h to obtain porous carbon / ceramic composite functional materials.

5. The porous carbon / ceramic composite functional material for removing odorous organic pollutants from a site according to claim 1, characterized in that: The porous carbon / ceramic composite functional material purifies the organic pollutants and odors in the site. 90% <350℃.

6. The porous carbon / ceramic composite functional material for removing odorous organic pollutants from a site according to claim 1, characterized in that: The porous carbon / ceramic composite functional material is used to remove odorous organic pollutants from the site. Odorous gases are collected under a canopy and transported under negative pressure to a purification reactor for removal of the odorous organic pollutants. The reaction temperature is 50–350℃, the concentration of odorous organic pollutants 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 ); After the reaction was completed, the intensity of the exhaust odor was evaluated according to the sensory description of the "Three-Point Comparison Odor Bag Method". Under the condition of 300~350℃, the purified exhaust gas had no odor.

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