Biochar composition as well as preparation method and application thereof

Abstract

The invention discloses a biochar composition as well as a preparation method and application thereof, and belongs to the technical field of water treatment. The biochar composition comprises the following components: 0.5-4 parts of straw, 1-3 parts of corncob and 1-7 parts of bagasse, after crushing treatment, the straw and the corncob are soaked in quicklime and water, the bagasse is soaked in zinc chloride, the pH is adjusted to be slightly alkaline, then solids are sieved out, two parts of solids are carbonized at high temperature, and the carbonized solids are put into sewage for use. As a novel external carbon source, the biochar composition disclosed by the invention applies agricultural wastes, is wide in raw material source, realizes waste reutilization, is environment-friendly, contains abundant carbon sources, and is beneficial to being applied to a later denitrification link; meanwhile, the unique pore structure of the biochar composition obtained at low temperature and low energy consumption provides a place for microorganism breeding, and the denitrification rate is remarkably improved, so that the denitrification efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a biochar composition and a preparation method and application thereof. Background Art

[0002] As one of the world's major agricultural countries, China has huge reserves of straw and corn cobs. The use of discarded straw and corn cobs to prepare biochar not only realizes the waste utilization of straw and corn cobs, but also can prepare biochar as an additional carbon source for sewage treatment. Bagasse is the residue after sugarcane is squeezed to extract juice. Its main components include cellulose, hemicellulose and lignin, which can all be used as raw materials for the preparation of carbon sources. Biochar is the residual carbon-rich product after high-temperature pyrolysis of biomass under anaerobic or oxygen-limited conditions. Biochar is a multi-carbon substance containing a variety of surface functional groups, with a developed pore structure and a highly chemically stable molecular structure. External carbon source technology has become an important means to improve denitrification efficiency. By adding external organic carbon sources, such as sodium acetate, the supply of carbon sources required in the denitrification reaction can be effectively increased, thereby accelerating the nitrogen conversion process and achieving the purpose of denitrification. At present, the preparation of biochar from corn cobs mostly uses a mixture of multiple strains or a mixture of multiple reagents or a mixture of strains and reagents, which has the disadvantages of high cost, complex composition, and relatively low safety factor. For example, CN114645000B provides a microbial-biochar composition and its preparation method and application, but this technology uses multiple strains for treatment, the reaction is relatively strict and the requirements on the environment are relatively strict. Patent CN117361748B provides a carbon source, preparation method and application for wastewater denitrification treatment, but the raw materials used in this technology are relatively complex and require multiple equipment assistance. Patent CN108786730B provides a method for preparing a corn straw biochar-based composite adsorbent, but this technology uses organic reagents for treatment, which is prone to side reactions. Summary of the invention

[0003] One purpose of the present invention is to provide a biochar composition, which is prepared by using straw, corn cobs and sugarcane bagasse to provide a rich external carbon source for denitrification treatment of sewage, greatly improve the denitrification efficiency, have low cost and realize the recycling of agricultural waste; another purpose is to provide a method for preparing a biochar composition, which has a simple process and easy-to-control conditions.

[0004] To achieve the above object, the present invention provides the following technical solutions: A biochar composition, comprising the following components by weight: 0.5-4 parts of straw; 1-3 servings of corn cobs; 1-7 parts of bagasse; Among them, the carbonization ratio of the biochar composition reaches 30%.

[0005] Preferably, the biochar composition comprises the following components by weight: 1-1.5 parts of straw; 1.5-2 servings of corn cobs; 2-3 parts of sugarcane bagasse.

[0006] As a more preferred embodiment, the biochar composition comprises the following components by weight: 1 portion of straw; 2 portions of corn cobs; 3 parts of bagasse.

[0007] The particle size of the straw is 1-2 cubic centimeters, the size of the corn cob is 1-2 cubic centimeters, and the length of the bagasse is 1-3 centimeters.

[0008] The present invention also provides another technical solution: A method for preparing a biochar composition comprises the following steps: a. Composition treatment: soak the straw and corn cobs with 8-9 parts of quicklime and water and let stand for 18-24h; soak the bagasse with 20% zinc chloride solution at a ratio of 1:50g / ml for 18-24h; b. Adjust pH value: Use water to adjust the pH value of the alkaline solution to 7-9; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: the composition is placed in a nitrogen-protected tubular furnace and treated at 200-250°C for 0.8-1.5 hours to achieve carbonization of part of the composition; e. Drying: Let stand for 24 hours and dry.

[0009] Preferably, the amount of quicklime in step a is 8 parts.

[0010] Preferably, the pH value of the solution in step b is 8.

[0011] Preferably, in step d, the heating rate is 10°C·min-1 from room temperature to the set temperature.

[0012] Preferably, in step d, the carbonization temperature is 200° C. and the treatment time is 1 hour.

[0013] The biochar composition is applied to sewage denitrification treatment and is used as an external carbon source to control TN in the water body to 10-13 mg / L.

[0014] The added amount of the biochar composition is 10%-35%.

[0015] The biochar prepared by the present invention is a multi-carbon substance containing multiple surface functional groups, having a developed pore structure and a highly chemically stable molecular structure. The completely carbonized part of the biochar composition has a high specific surface area and a rich microporous structure, and can effectively adsorb organic matter, heavy metal ions and nutrients in sewage; the incompletely carbonized part can be gradually decomposed during the microbial metabolism process, providing a continuous carbon source for the microorganisms. It helps to maintain the activity of microorganisms, especially in long-term sewage treatment systems, and can effectively improve the stability and treatment efficiency of the system. The main components of sugarcane bagasse include cellulose, hemicellulose and lignin, which can all be used as raw materials for the preparation of carbon sources. Biochar provides a good attachment and growth environment for denitrifying bacteria. Denitrifying bacteria can form a biofilm on the surface of biochar, thereby enhancing the ability to degrade organic pollutants and improving denitrification efficiency.

[0016] Therefore, the present invention has the following beneficial effects: agricultural waste straw, corn cobs, and bagasse are used to prepare a semi-carbonized biochar composition under a state of low energy consumption, the raw material source is wide, waste recycling is achieved, and it is environmentally friendly, and it contains rich carbon sources, which provides an additional carbon source for the denitrification link, and its unique pore structure provides a place for microbial reproduction, greatly improving the denitrification efficiency; the preparation method is simple, the process conditions are easy to control, and the cost is low. DETAILED DESCRIPTION

[0017] The present invention is further described below by means of specific embodiments, but the protection scope of the present invention is not limited thereto.

[0018] Example 1 A biochar composition comprises the following components: 1 part of straw, 2 parts of corn cobs and 3 parts of sugarcane bagasse.

[0019] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0020] The specific operations of this embodiment are: a. Composition treatment: Take 1 part of straw, 2 parts of corn cobs, and 3 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0021] Example 2 A biochar composition comprises the following components: 0.5 parts of straw, 1 part of corn cob and 1 part of sugarcane bagasse.

[0022] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0023] The specific operations of this embodiment are: a. Composition treatment: Take 0.5 parts of straw, 1 part of corn cob, and 1 part of bagasse, soak the straw and corn cob with 8 parts of quicklime and water, and let it stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1 Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0024] Example 3 A biochar composition comprises the following components: 4 parts of straw, 3 parts of corn cobs and 7 parts of sugarcane bagasse.

[0025] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0026] The specific operations of this embodiment are: a. Composition treatment: Take 4 parts of straw, 3 parts of corn cobs, and 7 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1 Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0027] Example 4 A biochar composition comprises the following components: 1 part of straw, 1.5 parts of corn cobs and 2 parts of sugarcane bagasse.

[0028] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0029] The specific operations of this embodiment are: a. Composition treatment: Take 1 part of straw, 1.5 parts of corn cobs, and 2 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1 Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0030] Example 5 A biochar composition comprises the following components: 0.5 parts of straw, 2 parts of corn cobs and 3 parts of sugarcane bagasse.

[0031] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0032] The specific operations of this embodiment are: a. Composition treatment: Take 0.5 parts of straw, 2 parts of corn cobs, and 3 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1 Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0033] Example 6 A biochar composition comprises the following components: 1.5 parts of straw, 2 parts of corn cobs and 3 parts of sugarcane bagasse.

[0034] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0035] The specific operations of this embodiment are: a. Composition treatment: Take 1 part of straw, 2 parts of corn cobs, and 3 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1 Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0036] Example 7 A biochar composition comprises the following components: 4 parts of straw, 2 parts of corn cobs and 3 parts of sugarcane bagasse.

[0037] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0038] The specific operations of this embodiment are: a. Composition treatment: Take 4 parts of straw, 2 parts of corn cobs, and 3 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1 Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0039] Example 8 A biochar composition comprises the following components: 1 part of straw, 1 part of corn cob and 3 parts of sugarcane bagasse.

[0040] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0041] The specific operations of this embodiment are: a. Composition treatment: Take 1 part of straw, 1 part of corn cob, and 3 parts of bagasse, soak the straw and corn cob with 8 parts of quicklime and water, and let it stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1 Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0042] Example 9 A biochar composition comprises the following components: 1 part of straw, 1.5 parts of corn cobs and 3 parts of sugarcane bagasse.

[0043] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0044] The specific operations of this embodiment are: a. Composition treatment: Take 1 part of straw, 1.5 parts of corn cobs, and 3 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1 Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0045] Example 10 A biochar composition comprises the following components: 1 part of straw, 3 parts of corn cobs and 3 parts of sugarcane bagasse.

[0046] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0047] The specific operations of this embodiment are: a. Composition treatment: Take 1 part of straw, 3 parts of corn cobs, and 3 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1 Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0048] Embodiment 11 A biochar composition comprises the following components: 1 part of straw, 2 parts of corn cobs and 1 part of sugarcane bagasse.

[0049] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0050] The specific operations of this embodiment are: a. Composition treatment: Take 1 part of straw, 2 parts of corn cobs, and 1 part of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1 Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0051] Example 12 A biochar composition comprises the following components: 1 part of straw, 2 parts of corn cobs and 2 parts of sugarcane bagasse.

[0052] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0053] The specific operations of this embodiment are: a. Composition treatment: Take 1 part of straw, 2 parts of corn cobs, and 2 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1 Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0054] Example 13 A biochar composition comprises the following components: 1 part of straw, 2 parts of corn cobs and 7 parts of sugarcane bagasse.

[0055] A method for preparing a biochar composition comprises the following steps: composition treatment, pH adjustment, screening, high-temperature carbonization, and drying.

[0056] The specific operations of this embodiment are: a. Composition treatment: Take 1 part of straw, 2 parts of corn cobs, and 7 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composite was placed in a nitrogen-protected tubular furnace at 10°C min -1 Heating from room temperature to a set temperature, treating at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0057] Comparative Example 1 This comparative example provides a method for preparing a biochar composition, comprising the following steps: The composition is treated, pH is adjusted, sieving, high temperature carbonization and drying are performed.

[0058] The specific operation of this comparative example is: a. Composition treatment: Take 4 parts of straw and 2 parts of corn cobs, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24h; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composition was placed in a nitrogen-protected tubular furnace, heated from room temperature to a set temperature at 10°C min-1, and treated at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0059] Comparative Example 2 This comparative example provides a method for preparing a biochar composition, comprising the following steps: The composition is treated, pH is adjusted, sieving, high temperature carbonization and drying are performed.

[0060] The specific operation of this comparative example is: a. Composition treatment: Take 2 parts of corn cobs and 4 parts of bagasse, soak the corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composition was placed in a nitrogen-protected tubular furnace, heated from room temperature to a set temperature at 10°C min-1, and treated at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0061] Comparative Example 3 This comparative example provides a method for preparing a biochar composition, comprising the following steps: The composition is treated, pH is adjusted, sieving, high temperature carbonization and drying are performed.

[0062] The specific operation of this comparative example is: a. Composition treatment: Take 1 part of straw and 5 parts of bagasse, soak the straw with 8 parts of quicklime and water, and let it stand for 24h; soak the bagasse with 20% zinc chloride solution at a ratio of 1:50g / ml for 24h; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composition was placed in a nitrogen-protected tubular furnace, heated from room temperature to a set temperature at 10°C min-1, and treated at 200°C for 1 hour to achieve 30% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0063] Comparative Example 4 This comparative example provides a method for preparing a biochar composition, comprising the following steps: The composition is treated, pH is adjusted, sieving, high temperature carbonization and drying are performed.

[0064] The specific operation of this comparative example is: a. Composition treatment: Take 5 parts of straw, 2 parts of corn cobs and 3 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composition was placed in a nitrogen-protected tubular furnace, heated from room temperature to a set temperature at 10°C min-1, and treated at 200°C for 1 hour to achieve carbonization of 22.1% of the composition; e. Drying: Let stand for 24 hours.

[0065] Comparative Example 5 This comparative example provides a method for preparing a biochar composition, comprising the following steps: The composition is treated, pH is adjusted, sieving, high temperature carbonization and drying are performed.

[0066] The specific operation of this comparative example is: a. Composition treatment: Take 1 part of straw, 5 parts of corn cobs and 3 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with a 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composition was placed in a nitrogen-protected tubular furnace, heated from room temperature to a set temperature at 10°C min-1, and treated at 200°C for 1 hour to achieve carbonization of 19.8% of the composition; e. Drying: Let stand for 24 hours.

[0067] Comparative Example 6 This comparative example provides a method for preparing a biochar composition, comprising the following steps: The composition is treated, pH is adjusted, sieving, high temperature carbonization and drying are performed.

[0068] The specific operation of this comparative example is: a. Composition treatment: Take 1 part of straw, 2 parts of corn cobs and 8 parts of bagasse, soak the straw and corn cobs with 8 parts of quicklime and water, and let stand for 24 hours; soak the bagasse with 20% zinc chloride solution at a ratio of 1:50g / ml for 24 hours; b. Adjust pH: Use water to adjust the pH value of the alkaline solution to 8; c. Sieve: Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. High temperature carbonization: The composition was placed in a nitrogen-protected tubular furnace, heated from room temperature to a set temperature at 10°C min-1, and treated at 200°C for 1 hour to achieve 17% carbonization of the composition; e. Drying: Let stand for 24 hours.

[0069] Performance Testing The prepared biochar composition was put into sewage to measure its reverse digestion rate, total nitrogen removal rate and TN of effluent water quality. The test results are shown in Table 1.

[0070] As shown in Table 1, the denitrification rates of the wastewater in Examples 1-13 were all higher than 0.30 kg NO - 3 -N / (kg·MLSS·d), Example 1 has the best effect, up to 0.39kgNO - 3 -N / (kg·MLSS·d), which are all higher than those of comparative examples 1-6, and the denitrification rate is increased by more than 20%; the total nitrogen removal rates of embodiments 1-13 are all higher than 90%, and embodiment 1 has the best effect, up to 98%, which are all higher than those of comparative examples 1-6, and the total nitrogen removal rate is increased by more than 10%; the effluent water quality TN of embodiments 1-13 is stable at 10-13 mg / L, meeting the 15 mg / l index required by the first-level A standard. Therefore, the present invention uses straw, corn cobs and bagasse in a specific ratio range as raw materials to prepare a 30% carbonized biochar composition as an added carbon source, which has a high total nitrogen removal rate and a fast denitrification rate.

Claims

1. A biochar composition, characterized in that: By weight, it includes the following components: 0.5-4 parts of straw; 1-3 servings of corn cobs; 1-7 parts of bagasse; Among them, the carbonization ratio of the biochar composition reaches 30%.

2. A biochar composition according to claim 1, characterized in that: The composition comprises the following components by weight: 1-1.5 parts of straw; 1.5-2 servings of corn cobs; 2-3 parts of sugarcane bagasse.

3. A biochar composition according to claim 1, characterized in that: The composition comprises the following components by weight: 1 part of straw; 2 portions of corn cobs; 3 parts of bagasse.

4. A biochar composition according to claim 1 or 3, characterized in that: The particle size of the straw is 1-2 cubic centimeters, the size of the corn cob is 1-2 cubic centimeters, and the length of the bagasse is 1-3 centimeters.

5. A method for preparing a biochar composition, characterized in that: The following steps are involved: a. Soak the straw and corn cobs with 8-9 parts of quicklime and water and let stand for 18-24 hours; soak the bagasse with 20% zinc chloride solution at a ratio of 1:50g / ml for 18-24 hours; b. Use water to adjust the pH value of the alkaline solution to 7-9; c. Sieve the two solutions, remove the solids, and dry at 60°C for 30 minutes; d. The composition is placed in a nitrogen-protected tubular furnace and treated at 200-250° C. for 0.8-1.5 hours to achieve carbonization of part of the composition; e. Let stand for 24 hours and dry.

6. The method for preparing a biochar composition according to claim 5, characterized in that: In the step a, the amount of quicklime is 8 parts.

7. The method for preparing a biochar composition according to claim 5, characterized in that: The pH value of the solution in step b is 8.

8. The method for preparing a biochar composition according to claim 5, characterized in that: The heating rate in step d is 10°C·min -1 Heat from room temperature to set temperature.

9. The method for preparing a biochar composition according to claim 5, characterized in that: In the step d, the carbonization temperature is 200° C. and the treatment time is 1 hour.

10. Use of the biochar composition according to any one of claims 1 to 4 in sewage treatment, characterized in that: The addition amount is 10%-35%.

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