Biochemical sludge doped organic matter activated carbon and preparation method thereof

Abstract

The invention discloses activated carbon with biochemical sludge doped with organic matter and a preparation method thereof.The preparation method comprises the following steps that the biochemical sludge is subjected to dehydration pretreatment and fully mixed with the organic matter, then drying and smashing are conducted, and standby sludge particles are obtained; carbonizing the standby sludge particles at constant temperature, and grinding to obtain carbonized material powder; mixing the carbonized material powder with an activating agent, adding the mixture into deionized water, carrying out water-bath heating reaction, and filtering and drying a product; performing constant-temperature activation under the protection of inert gas to obtain an activated product; and placing the activated product in concentrated acid for ultrasonic treatment, and then washing, drying and crushing to obtain the product. According to the method, the biochemical sludge is prepared into the activated carbon, waste is turned into wealth, resource utilization of the biochemical sludge is achieved, the treatment cost of the biochemical sludge is saved, environmental benefits and economic benefits are achieved, and the obtained activated carbon is stable in structure, developed in pores, large in specific surface area and high in adsorbability.

Description

Technical Field

[0001] This invention relates to the field of biochemical sludge treatment technology, specifically to activated carbon made by doping biochemical sludge with organic matter and its preparation method. Background Technology

[0002] With the acceleration of urbanization in my country, the increase in urban industry and population is constantly testing the carrying capacity of the urban environment. To improve the urban living environment, a large number of new urban sewage treatment plants have been built, while older plants are being upgraded and renovated. This inevitably leads to a sharp increase in sludge. Sludge typically contains heavy metals and various pathogenic microorganisms, making direct reuse difficult. Considering the large amount of organic matter in sludge, using the carbonization of excess sludge to prepare sludge activated carbon with good adsorption properties can achieve sludge reduction, resource recovery, and harmlessness, thus achieving the goal of comprehensive utilization of hazardous waste.

[0003] Using sludge activated carbon to replace traditional activated carbon for the adsorption and removal of pollutants in water and the atmosphere has good economic and social benefits, and has attracted great attention from researchers at home and abroad.

[0004] Therefore, this invention proposes a method for preparing activated carbon by incorporating organic matter into biochemical sludge. The method involves dewatering and carbonizing the biochemical sludge, and then activating and modifying it by adding an activator to prepare sludge activated carbon. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide activated carbon doped with organic matter from biochemical sludge and its preparation method, thereby effectively producing an activated carbon material with stable structure, strong adsorption capacity, and large specific surface area.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing activated carbon mixed with organic matter from biochemical sludge includes the following steps:

[0008] (1) The biochemical sludge is dewatered and pretreated, then thoroughly mixed with organic matter, dried to constant weight, crushed and sieved to obtain sludge granules for later use.

[0009] Preferably, in step (1), the organic matter is one or more of straw, leaves, coconut shell, waste paper, and rice husk; the mass ratio of organic matter added to the dewatered pretreated biochemical sludge is 10-40:100.

[0010] Preferably, in step (1), the moisture content of the biochemical sludge after dewatering is maintained at 50-80 wt%; the drying conditions are drying in a drying oven at 100-105℃ for 12-24 hours; and pulverizing to 60-100 mesh.

[0011] (2) Place the spare sludge particles in a high-temperature tube furnace and carbonize them at a constant temperature under the protection of inert gas. After carbonization, cool them to room temperature under the protection of inert gas, take them out and grind them into powder to obtain carbonized material powder.

[0012] Preferably, in step (2), the carbonization conditions are to heat to 350-500℃ at a heating rate of 2-10℃ / min and carbonize at a constant temperature for 1-2 hours.

[0013] Preferably, in step (2), the inert gas is one or more of high-purity nitrogen, high-purity argon, and high-purity carbon dioxide.

[0014] (3) Mix the carbonized material powder with the activator, then add it to deionized water, disperse it evenly under ultrasonic action, fully wet it, heat it in a water bath to react, filter and dry the product;

[0015] Preferably, in step (3), the activator is one or more of zinc chloride, potassium hydroxide, and sodium hydroxide.

[0016] Preferably, in step (3), the mass ratio of carbonized material powder to activator is 1:1 to 5; the ratio of carbonized material powder to deionized water is 1g:50 to 150mL; the water bath heating reaction conditions are 60 to 80℃ for 10 to 15h; and the drying conditions are 100 to 105℃ for 2 to 4h.

[0017] (4) Place the product obtained in step (3) in a high-temperature tube furnace and activate it at a constant temperature under the protection of an inert gas. After activation, continue to cool it to room temperature under the protection of an inert gas to obtain the activated product.

[0018] Preferably, in step (4), the activation conditions are to heat to 600-800℃ at a heating rate of 2-10℃ / min and activate at a constant temperature for 1-2 hours.

[0019] Preferably, in step (4), the inert gas is one or more of high-purity nitrogen, high-purity argon, and high-purity carbon dioxide.

[0020] (5) The activated product is placed in concentrated acid and ultrasonically treated, then washed, dried, and then crushed and ground to obtain the activated carbon of the biochemical sludge mixed with organic matter.

[0021] Preferably, in step (5), the ultrasonic treatment time is 10-30 min, the washing is done with 80℃ deionized water, the drying conditions are drying at 105℃ for 10-15 h, and grinding is passed through a 100-200 mesh sieve.

[0022] Preferably, in step (5), the concentrated acid is concentrated hydrochloric acid and / or concentrated nitric acid, and the mass fraction of the concentrated acid is 15-40%.

[0023] This invention also claims protection for activated carbon made from biochemical sludge doped with organic matter, prepared using the aforementioned preparation method.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The activated carbon obtained by the method of the present invention has a stable structure, well-developed pores, large specific surface area and strong adsorption.

[0026] (2) This invention prepares activated carbon from biochemical sludge, turning waste into treasure, realizing the resource utilization of biochemical sludge, saving the treatment cost of biochemical sludge, and has environmental and economic benefits.

[0027] (3) The operation method of the present invention is simple and feasible, the reaction conditions are relatively mild, energy saving and environmental protection are environmentally friendly, the post-processing process is simple and highly repeatable. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some schematic diagrams of certain embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the process for preparing activated carbon according to the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0031] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0032] A method for preparing activated carbon mixed with organic matter from biochemical sludge includes the following steps:

[0033] (1) The biochemical sludge is dewatered and pretreated, then thoroughly mixed with organic matter, dried to constant weight, crushed and sieved to obtain sludge granules for later use.

[0034] In step (1), the organic matter is one or more of straw, leaves, coconut shells, waste paper, and rice husks; the mass ratio of organic matter added to the dewatered pretreated biochemical sludge is 10-40:100.

[0035] In step (1), the moisture content of the biochemical sludge after dewatering is maintained at 50-80 wt%; the drying conditions are drying in a drying oven at 100-105℃ for 12-24 hours; and pulverizing to 60-100 mesh.

[0036] (2) Place the spare sludge particles in a high-temperature tube furnace and carbonize them at a constant temperature under the protection of inert gas. After carbonization, cool them to room temperature under the protection of inert gas, take them out and grind them into powder to obtain carbonized material powder.

[0037] In step (2), the carbonization conditions are to heat to 350-500℃ at a heating rate of 2-10℃ / min and carbonize at a constant temperature for 1-2 hours.

[0038] In step (2), the inert gas is one or more of high-purity nitrogen, high-purity argon, and high-purity carbon dioxide.

[0039] (3) Mix the carbonized material powder with the activator, then add it to deionized water, disperse it evenly under ultrasonic action, fully wet it, heat it in a water bath to react, filter and dry the product;

[0040] In step (3), the activator is one or more of zinc chloride, potassium hydroxide, and sodium hydroxide.

[0041] In step (3), the mass ratio of carbonized material powder to activator is 1:1 to 5; the ratio of carbonized material powder to deionized water is 1g:50 to 150mL; the water bath heating reaction conditions are 60 to 80℃ for 10 to 15h; and the drying conditions are 100 to 105℃ for 2 to 4h.

[0042] (4) Place the product obtained in step (3) in a high-temperature tube furnace and activate it at a constant temperature under the protection of an inert gas. After activation, continue to cool it to room temperature under the protection of an inert gas to obtain the activated product.

[0043] In step (4), the activation conditions are to heat to 600-800℃ at a heating rate of 2-10℃ / min and activate at a constant temperature for 1-2 hours.

[0044] In step (4), the inert gas is one or more of high-purity nitrogen, high-purity argon, and high-purity carbon dioxide.

[0045] (5) The activated product is placed in concentrated acid and ultrasonically treated, then washed, dried, and then crushed and ground to obtain the activated carbon of the biochemical sludge mixed with organic matter.

[0046] In step (5), the ultrasonic treatment time is 10-30 min, the washing is done with 80℃ deionized water, the drying conditions are drying at 105℃ for 10-15 h, and grinding is passed through a 100-200 mesh sieve.

[0047] In step (5), the concentrated acid is concentrated hydrochloric acid and / or concentrated nitric acid, and the mass fraction of the concentrated acid is 15-40%.

[0048] The present invention will be further described below through specific embodiments.

[0049] Example 1

[0050] A method for preparing activated carbon mixed with organic matter from biochemical sludge includes the following steps:

[0051] (1) The biochemical sludge collected from a municipal sewage treatment plant was dewatered and pretreated to make the water content about 60%. It was then fully mixed with rice husks, with the rice husks accounting for 15% of the sludge mass. The mixture was then dried in a drying oven at 105°C for 15 hours until constant weight was achieved. The sludge was then crushed and passed through a 60-mesh sieve to obtain spare sludge particles.

[0052] (2) Place the spare sludge particles in a high-temperature tube furnace and heat them to 400°C at a heating rate of 5°C / min under the protection of inert gas. Carbonize them at a constant temperature for 2 hours. Then stop heating and continue to cool them to room temperature under the protection of nitrogen. Take them out and grind them into powder to obtain carbonized material powder.

[0053] (3) Mix the carbonized material powder and the activator zinc chloride at a mass ratio of 1:1, then add it to deionized water with a mass-volume ratio of 1g:100mL to the carbonized material powder, disperse it evenly under ultrasonic action, fully impregnate it, heat it in a water bath at 80℃ for 15h, and finally put it in a drying oven and dry it at 105℃ for 4h.

[0054] (4) The dried product was placed in a high-temperature tube furnace and heated to 800°C at a rate of 5°C / min under nitrogen protection. It was kept at a constant temperature for 2 hours. Then the heating was stopped and the product was cooled to room temperature under nitrogen protection to obtain the activated product.

[0055] (5) Place the activated product in concentrated hydrochloric acid and ultrasonically soak for 30 min. Then wash it with deionized water at 80°C until neutral. Place the product in a drying oven and dry it at 105°C for 15 h. Take it out and grind it. Pass it through a 100-mesh sieve to obtain powdered activated carbon.

[0056] The iodine value of the activated carbon prepared under these conditions can reach 956.27 mg / g. When used to treat wastewater effluent from wastewater treatment plants, it can achieve a COD removal rate of over 50%; and the decolorization rate of dye wastewater can reach 90%.

[0057] Example 2

[0058] A method for preparing activated carbon mixed with organic matter from biochemical sludge includes the following steps:

[0059] (1) The biochemical sludge collected from the sewage treatment plant in a certain industrial park was dewatered and pretreated to make the water content about 60%. It was then thoroughly mixed with chopped straw, with the straw accounting for 10% of the sludge mass. The mixture was then dried in a drying oven at 105℃ for 15 hours until constant weight was achieved. The mixture was then crushed and passed through a 60-mesh sieve to obtain spare sludge particles.

[0060] (2) Place the spare sludge particles in a high-temperature tube furnace and heat them to 400°C at a heating rate of 5°C / min under the protection of inert gas. Carbonize them at a constant temperature for 2 hours. Then stop heating and continue to cool them to room temperature under the protection of nitrogen. Take them out and grind them into powder to obtain carbonized material powder.

[0061] (3) Mix the carbonized material powder and the activator zinc chloride at a mass ratio of 1:1, then add it to deionized water with a mass-volume ratio of 1g:100mL to the carbonized material powder, disperse it evenly under ultrasonic action, fully impregnate it, heat it in a water bath at 80℃ for 15h, and finally put it in a drying oven and dry it at 105℃ for 4h.

[0062] (4) The dried product was placed in a high-temperature tube furnace and heated to 800°C at a rate of 5°C / min under nitrogen protection. It was kept at a constant temperature for 2 hours. Then the heating was stopped and the product was cooled to room temperature under nitrogen protection to obtain the activated product.

[0063] (5) Place the activated product in concentrated hydrochloric acid and ultrasonically soak for 30 min. Then wash it with deionized water at 80°C until neutral. Place the product in a drying oven and dry it at 105°C for 15 h. Take it out and grind it. Pass it through a 100-mesh sieve to obtain powdered activated carbon.

[0064] The iodine value of the activated carbon prepared under these conditions can reach 911.08 mg / g. When used to treat coking wastewater, it can remove part of the COD and ammonia nitrogen, and has a good color removal effect, with a decolorization rate of over 80%.

[0065] Comparative Example 1

[0066] A method for preparing activated carbon mixed with organic matter from biochemical sludge includes the following steps:

[0067] (1) The biochemical sludge collected from a municipal sewage treatment plant was dewatered and pretreated to make the water content about 60%. Then it was dried in a drying oven at 105℃ for 15 hours until constant weight. Then it was crushed and passed through a 60-mesh sieve to obtain sludge particles for use.

[0068] (2) Place the spare sludge particles in a high-temperature tube furnace and heat them to 400°C at a heating rate of 5°C / min under the protection of inert gas. Carbonize them at a constant temperature for 2 hours. Then stop heating and continue to cool them to room temperature under the protection of nitrogen. Take them out and grind them into powder to obtain carbonized material powder.

[0069] (3) Mix the carbonized material powder and the activator zinc chloride at a mass ratio of 1:1, then add it to deionized water with a mass-volume ratio of 1g:100mL to the carbonized material powder, disperse it evenly under ultrasonic action, fully impregnate it, heat it in a water bath at 80℃ for 15h, and finally put it in a drying oven and dry it at 105℃ for 4h.

[0070] (4) The dried product was placed in a high-temperature tube furnace and heated to 800°C at a rate of 5°C / min under nitrogen protection. It was kept at a constant temperature for 2 hours. Then the heating was stopped and the product was cooled to room temperature under nitrogen protection to obtain the activated product.

[0071] (5) Place the activated product in concentrated hydrochloric acid and ultrasonically soak for 30 min. Then wash it with deionized water at 80°C until neutral. Place the product in a drying oven and dry it at 105°C for 15 h. Take it out and grind it. Pass it through a 100-mesh sieve to obtain powdered activated carbon.

[0072] The iodine value of the activated carbon prepared under these conditions is 782.39 mg / g. It can achieve a COD removal rate of over 40% when treating wastewater effluent from wastewater treatment plants, and a decolorization rate of up to 75% when treating dye wastewater.

[0073] Comparative Example 2

[0074] A method for preparing activated carbon mixed with organic matter from biochemical sludge includes the following steps:

[0075] (1) The biochemical sludge collected from a municipal sewage treatment plant was dewatered and pretreated to make the water content about 60%. It was then fully mixed with rice husks, with the rice husks accounting for 15% of the sludge mass. The mixture was then dried in a drying oven at 105°C for 15 hours until constant weight was achieved. The sludge was then crushed and passed through a 60-mesh sieve to obtain spare sludge particles.

[0076] (2) Place the spare sludge particles in a high-temperature tube furnace and heat them to 400°C at a heating rate of 5°C / min under the protection of inert gas. Carbonize them at a constant temperature for 2 hours. Then stop heating and continue to cool them to room temperature under the protection of nitrogen. Take them out and grind them into powder to obtain carbon powder.

[0077] (3) Place the carbonized material powder in concentrated hydrochloric acid and ultrasonically soak for 30 minutes. Then wash it with deionized water at 80°C until neutral. Place the product in a drying oven and dry it at 105°C for 15 hours. Take it out and crush and grind it. Pass it through a 100-mesh sieve to obtain powdered carbonized material.

[0078] The carbonized powder prepared under these conditions has an iodine value of 231.92 mg / g. However, it is difficult to remove COD and ammonia nitrogen when treating coking wastewater, and the color removal effect is poor, with a decolorization rate of about 30%.

[0079] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing activated carbon mixed with organic matter from biochemical sludge, comprising the following steps: (1) The biochemical sludge is dewatered and pretreated, then thoroughly mixed with organic matter, dried to constant weight, crushed and sieved to obtain sludge granules for later use. (2) Place the spare sludge particles in a high-temperature tube furnace and carbonize them at a constant temperature under the protection of inert gas. After carbonization, cool them to room temperature under the protection of inert gas, take them out and grind them into powder to obtain carbonized material powder. (3) Mix the carbonized material powder with the activator, then add it to deionized water, disperse it evenly under ultrasonic action, fully wet it, heat it in a water bath to react, filter and dry the product; (4) Place the product obtained in step (3) in a high-temperature tube furnace and activate it at a constant temperature under the protection of an inert gas. After activation, continue to cool it to room temperature under the protection of an inert gas to obtain the activated product. (5) The activated product is placed in concentrated acid and ultrasonically treated, then washed, dried, and then crushed and ground to obtain the activated carbon of the biochemical sludge mixed with organic matter.

2. The preparation method according to claim 1, characterized in that, In step (1), the organic matter is one or more of straw, leaves, coconut shells, waste paper, and rice husks; the mass ratio of organic matter added to the dewatered pretreated biochemical sludge is 10-40:

100.

3. The preparation method according to claim 1, characterized in that, In step (1), the moisture content of the biochemical sludge after dewatering is maintained at 50-80 wt%; the drying conditions are drying in a drying oven at 100-105℃ for 12-24 hours; and pulverizing to 60-100 mesh.

4. The preparation method according to claim 1, characterized in that, In step (2), the carbonization conditions are to heat to 350-500℃ at a heating rate of 2-10℃ / min and carbonize at a constant temperature for 1-2 hours.

5. The preparation method according to claim 1, characterized in that, In step (3), the activator is one or more of zinc chloride, potassium hydroxide, and sodium hydroxide.

6. The preparation method according to claim 1, characterized in that, In step (3), the mass ratio of carbonized material powder to activator is 1:1 to 5; the ratio of carbonized material powder to deionized water is 1g:50 to 150mL; the water bath heating reaction conditions are 60 to 80℃ for 10 to 15h; and the drying conditions are 100 to 105℃ for 2 to 4h.

7. The preparation method according to claim 1, characterized in that, In step (4), the activation conditions are to heat to 600-800℃ at a heating rate of 2-10℃ / min and activate at a constant temperature for 1-2 hours.

8. The preparation method according to claim 1, characterized in that, In step (5), the ultrasonic treatment time is 10-30 min, the washing is done with 80℃ deionized water, the drying conditions are drying at 105℃ for 10-15 h, and grinding is passed through a 100-200 mesh sieve.

9. The preparation method according to claim 1, characterized in that, In step (5), the concentrated acid is concentrated hydrochloric acid and / or concentrated nitric acid, and the mass fraction of the concentrated acid is 15-40%.

10. An activated carbon made from biochemical sludge doped with organic matter, prepared by the method according to any one of claims 1 to 9.

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