Spartina alterniflora modified charcoal for deodorizing kitchen waste and preparation method of spartina alterniflora modified charcoal

Abstract

The invention belongs to the technical field of biochar modification, and particularly relates to spartina alterniflora modified biochar for deodorizing kitchen waste and a preparation method of the spartina alterniflora modified biochar. The preparation method comprises the following steps: selecting a biomass raw material, and pretreating the biomass raw material to obtain dry biomass; putting the dried biomass into a high-temperature tube furnace, heating to 300-600 DEG C under an anoxic condition, carbonizing for 2 hours, pyrolyzing the biomass to form biochar, naturally cooling to room temperature, grinding, sieving, and storing for later use; biochar is soaked in an acid solution, and modified biochar is obtained after treatment. The spartina alterniflora modified charcoal can be applied to kitchen waste degradation equipment to remove volatile organic compounds in odor. The invention provides a new thought for realizing resource utilization and ecological environment protection of spartina alterniflora, and provides a theoretical basis and data support for odor pollution control in the operation process of kitchen waste degradation equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of biochar modification, and specifically relates to a Spartina alterniflora modified biochar, a preparation method and application thereof in removing volatile odors from kitchen waste. Background Art

[0002] With the rapid development of industrialization and urbanization, the odor pollution problem generated in industrial production, sewage treatment, landfill and agricultural activities is becoming increasingly serious. These odors are mainly composed of volatile organic compounds (VOCs), which not only seriously affect the quality of life and working environment of residents, but also may cause long-term harm to the ecological environment and human health. Therefore, the development of efficient, economical and environmentally friendly odor control technology has become an important issue that needs to be solved urgently.

[0003] Traditionally, activated carbon has been widely used in odor treatment due to its good adsorption performance. However, when dealing with complex odor components, especially low-concentration, highly toxic organic odor gases, traditional activated carbon has problems such as limited adsorption capacity, slow adsorption rate, easy saturation and difficult regeneration. These shortcomings limit the further application and development of traditional activated carbon in the field of odor treatment.

[0004] In order to overcome the above defects, researchers have begun to explore ways to improve the adsorption performance of activated carbon through modification in recent years. Modified biochar, as a new adsorption material made from biomass and processed through a specific process, has gradually become a research hotspot in the field of odor control due to its wide source of raw materials, strong renewability, diverse modification methods and good environmental protection.

[0005] In the prior art, some methods of modifying activated carbon require expensive chemical reagents or complex processes, which limits their large-scale application. In addition, the limited availability of certain biomass raw materials affects the sustainability of modified biochar. Although modified activated carbon can improve adsorption performance, existing methods cannot achieve efficient selective adsorption of specific odor components, resulting in low adsorption efficiency. By precisely regulating the pore structure and surface functional groups, the modified biochar with specific adsorption affinity can be developed to improve the selective adsorption efficiency of target odor components.

[0006] Therefore, it is crucial to provide a biochar that has a simple preparation method, is environmentally friendly, and can effectively remove odorous organic volatile components. Summary of the invention

[0007] In view of this, the purpose of the present invention is to provide a modified Spartina alterniflora biochar for deodorizing kitchen waste and a preparation method thereof. By selecting suitable biomass raw materials and combining innovative modification processes, a modified biochar with high adsorption performance, low cost and environmental protection is prepared to achieve efficient removal of organic components in odor.

[0008] It should be noted that modified biochar adjusts its pore structure, specific surface area and surface chemical properties through physical, chemical or biological methods, thereby significantly improving its adsorption capacity and selectivity for odorous organic components. For example, through acid washing, alkali washing, heat treatment, loading of metals or metal oxides, etc., rich functional groups can be formed on the surface of biochar, enhancing its adsorption affinity for specific organic matter; at the same time, optimizing the pore structure helps to increase the adsorption sites and improve the adsorption capacity and rate.

[0009] In order to achieve the above object, the present invention adopts the following technical solution:

[0010] The first technical purpose of the present invention is to provide a method for preparing Spartina alterniflora modified biochar, comprising the following steps:

[0011] 1) selecting a biomass raw material and pretreating the biomass raw material to obtain dry biomass;

[0012] 2) Put the dried biomass into a high-temperature tube furnace, heat it to 300-600℃ under anaerobic conditions, and carbonize it for 2 hours to pyrolyze the biomass to form biochar, cool it naturally to room temperature, grind it, sieve it, and store it for later use;

[0013] 3) The biochar is immersed in an acidic solution to obtain modified biochar after treatment.

[0014] Preferably, the biomass is Spartina alterniflora, and the pretreatment includes washing, removing impurities and drying the biomass.

[0015] Preferably, the pyrolysis conditions are nitrogen gas introduction and a heating rate of 5°C / min.

[0016] Preferably, the acidic solution is nitric acid, hydrogen peroxide, sulfuric acid, or sulfuric acid-hydrogen peroxide.

[0017] Preferably, the immersion conditions are placing in a magnetic stirrer and fully vibrating and stirring for 6 h to 8 h, filtering and drying, and drying at 60° C. to 80° C. for 24 h to 48 h.

[0018] The second technical purpose of the present invention is to provide a Spartina alterniflora modified biochar prepared by the above method.

[0019] The third technical purpose of the present invention is to provide an application of Spartina alterniflora modified biochar prepared by the above method in waste treatment and environmental management.

[0020] Furthermore, the Spartina alterniflora modified biochar is used in removing odorous volatile organic compounds in food waste degradation equipment.

[0021] Furthermore, the volatile organic compounds include α-terpineol, limonene and ethyl acetate.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The modified biochar prepared by the invention can be applied to a kitchen waste degradation device to remove volatile organic compounds in odor. The invention provides a new idea for realizing the resource utilization of Spartina alterniflora and ecological environment protection, and provides a theoretical basis and data support for the prevention and control of odor pollution during the operation of kitchen waste degradation equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0025] Figure 1 HNO 3 Removal of main odor components from kitchen waste by modified biochar.

[0026] Figure 2 H 2 O 2 Removal of main odor components from kitchen waste by modified biochar.

[0027] Figure 3 H 2 SO 4 Removal of main odor components from kitchen waste by modified biochar.

[0028] Figure 4 H 2 SO 4 -H 2 O 2 Removal of main odor components from kitchen waste by modified biochar.

[0029] Figure 5 The removal of the main components of kitchen waste odor by biochar using different types of biomass raw materials.

[0030] Figure 6 The removal of the main components of kitchen waste odor by biochar at different pyrolysis temperatures.

[0031] Figure 7 The removal of the main components of kitchen waste odor by biochar under different modification methods.

[0032] Figure 8Sensory analysis of the removal of odor from kitchen waste by biochar modified with Spartina alterniflora.

[0033] Fig. 9 SEM surface morphology of biochar modified by Spartina alterniflora.

[0034] Fig.10 FT-IR (a) and XPS (b) characterization analysis of Spartina alterniflora modified biochar. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The word "embodiment" used here as an "exemplary" does not necessarily mean that any embodiment described is superior to or better than other embodiments. Unless otherwise specified, the performance index tests in the embodiments of this application are performed using conventional test methods in the art. It should be understood that the terms described in this application are only used to describe specific implementation methods and are not used to limit the content disclosed in this application.

[0037] Unless otherwise specified, the technical and scientific terms used in this document have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0038] In order to better illustrate the content of the present application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0039] Under the premise of no conflict, the technical features disclosed in the embodiments of the present application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present application.

[0040] The present invention discloses a method for preparing Spartina alterniflora modified biochar for deodorizing kitchen waste, comprising the following steps:

[0041] 1) Selecting biomass raw materials and pre-treating the biomass raw materials (cleaning, removing impurities and drying) to obtain dry biomass;

[0042] 2) Put the dried biomass into a high-temperature tube furnace, heat it to 300-600°C under anaerobic conditions, and carbonize it for 2 hours to pyrolyze the biomass to form biochar, cool it naturally to room temperature, grind it, sieve it, and store it for later use;

[0043] 3) The biochar is immersed in an acidic solution to obtain modified biochar after treatment.

[0044] In the present invention, biochar is prepared in a tubular furnace. The tubular furnace is first evacuated, and nitrogen is filled at a rate of 80 mL / min before heating and during heating to continuously maintain the volume of nitrogen in the furnace to create anoxic and oxygen-limited conditions. The heating rate of the vacuum tubular furnace is set to 5 ° C / min. A certain mass of biochar sample is weighed in a quartz boat, placed in a high-temperature tubular furnace, maintained at 300-600 ° C, carbonized for 2 h, and naturally cooled to room temperature.

[0045] In the present invention, 5 g of Spartina alterniflora biochar was placed in a beaker, and 50 mL of different types of modified solutions (HNO 3 , H 2 SO 4 , H 2 O 2 , H 2 SO 4 -H 2 O 2 ), placed in a magnetic stirrer and fully vibrated and stirred for 6 hours, filtered and dried, and dried in an oven at 60°C for 24 hours.

[0046] In the present invention, the mass of Spartina alterniflora modified biochar is 1g, and the time for adsorbing odorous volatile organic components is 1 to 5 hours, specifically 1 hour, 2 hours, 3 hours, 4 hours and 5 hours.

[0047] In the present invention, the volatile organic compounds removed include: α-terpineol, limonene, and ethyl acetate.

[0048] In the present invention, a gas sampling pump is used to collect gas samples with a sampling flow rate of 500 mL / min. The samples are collected for 2 min into a 1 L aluminum foil composite film gas sampling bag. Each sample is measured in parallel 3 times. The analysis is completed within 48 hours after sample collection. The analysis uses a gas phase ion mobility spectrometer (GC-IMS) from GAS, Germany.

[0049] In order to better understand the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as a limitation of the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above invention content are also considered to fall within the protection scope of the present invention.

[0050] Example 1

[0051] Preparation conditions: Place Spartina alterniflora in a nitrogen tube furnace, heat to 400 °C and maintain for 2 h for pyrolysis to obtain Spartina alterniflora biochar; take 5 g of Spartina alterniflora biochar and add it to 50 mL of nitric acid (HNO 3 ) solution for 6 h, dried in an oven at 60 °C for 24 h, and then rinsed with deionized water three times to remove easily leached pollutants, and dried in an oven at 60 °C for another 24 h to obtain modified Spartina alterniflora biochar (HNO 3 -C).

[0052] Sample testing: Collect the gas around the equipment for 1h~5h, and analyze the removal of α-pineneol, limonene and ethyl acetate by nitric acid-modified Spartina alterniflora biochar.

[0053] HNO 3 Effect of modified biochar on the removal of main odor components of kitchen waste Figure 1 .

[0054] Example 2

[0055] Preparation conditions: Place Spartina alterniflora in a nitrogen tube furnace, heat to 400 °C and maintain for 2 h for pyrolysis to obtain Spartina alterniflora biochar; take 5 g of Spartina alterniflora biochar and add it to 50 mL of hydrogen peroxide (H 2 O 2 ) solution for 6 h, and then the material was dried in an oven at 60 °C for 24 h, and then rinsed with deionized water for 3 times to remove easily leached pollutants, and then dried in an oven at 60 °C for 24 h to obtain modified Spartina alterniflora biochar (H 2 O 2 -C).

[0056] Sample testing: Collect the gas around the equipment for 1h~5h, and analyze the removal of α-pineneol, limonene and ethyl acetate by hydrogen peroxide-modified Spartina alterniflora biochar.

[0057] H 2 O 2 Effect of modified biochar on the removal of main odor components of kitchen waste Figure 2 .

[0058] Example 3

[0059] Preparation conditions: Place Spartina alterniflora in a nitrogen tube furnace, heat to 400 °C and maintain for 2 h for pyrolysis to obtain Spartina alterniflora biochar; take 5 g of Spartina alterniflora biochar and add it to 50 mL of sulfuric acid (H 2 SO 4 ) solution for 6 h, and then the material was dried in an oven at 60 °C for 24 h, and then rinsed with deionized water for 3 times to remove easily leached pollutants, and then dried in an oven at 60 °C for 24 h to obtain modified Spartina alterniflora biochar (H 2SO 4 -C).

[0060] Sample testing: Collect the gas around the equipment for 1h~5h, and analyze the removal of α-pineneol, limonene and ethyl acetate by sulfuric acid-modified Spartina alterniflora biochar.

[0061] H 2 SO 4 Effect of modified biochar on the removal of main odor components of kitchen waste Figure 3 .

[0062] Example 4

[0063] Preparation conditions: Place Spartina alterniflora in a nitrogen tube furnace, heat to 400 °C and maintain for 2 h for pyrolysis to obtain Spartina alterniflora biochar; take 5 g of Spartina alterniflora biochar and add it to 50 mL of sulfuric acid (H 2 SO 4 ) solution with magnetic stirring for 6 h, the material was dried in an oven at 60 °C for 24 h, and then added to 50 mL of hydrogen peroxide (H 2 O 2 ) solution for 6 h, and then the material was dried in an oven at 60 °C for 24 h, and then rinsed with deionized water for 3 times to remove easily leached pollutants, and then dried in an oven at 60 °C for 24 h to obtain modified Spartina alterniflora biochar (H 2 SO 4 / H 2 O 2 -C).

[0064] Sample testing: Collect the gas around the equipment for 1h~5h, and analyze the removal of α-pineneol, limonene and ethyl acetate by sulfuric acid / hydrogen peroxide modified Spartina alterniflora biochar.

[0065] H 2 SO 4 -H 2 O 2 Effect of modified biochar on the removal of main odor components of kitchen waste Figure 4 .

[0066] In order to further demonstrate the beneficial effects of the present invention and to better understand the present invention, the following comparative examples and experimental examples are used to further illustrate the technical features disclosed in the present invention, but they should not be understood as limiting the present invention. Other improvements made by those skilled in the art based on the above invention content without creative work are also considered to fall within the scope of protection of the present invention.

[0067] Experimental Example 1

[0068] In this experiment, Spartina alterniflora, apple sawdust, coconut shells and corn cobs were selected as raw materials to prepare raw biochar. The odor removal effects of different types of biochar were compared, and the biochar with the best removal effect was selected.

[0069] Preparation conditions: Spartina alterniflora, apple sawdust, coconut shell, and corn cob were placed in a nitrogen tubular furnace, heated to 400°C and maintained for 2 hours for pyrolysis to obtain Spartina alterniflora biochar, apple sawdust biochar, coconut shell biochar, and corn cob biochar.

[0070] Sample testing: 1g of biochar was put into a tea bag and hung above the food waste mixing equipment. The gas around the equipment was collected at the same time and point, and GC-IMS was used to analyze the removal of α-pineneol, limonene and ethyl acetate by different types of biochar.

[0071] Effect of different types of biomass raw materials on the removal of main components of kitchen waste odor Figure 5 .

[0072] Experimental Example 2

[0073] In this experiment, Spartina alterniflora was selected as the raw material to prepare the original biochar. The odor removal effect of Spartina alterniflora biochar at 300℃~600℃ was compared, and the biochar with the optimal pyrolysis temperature was screened out.

[0074] Preparation conditions: The tube furnace was first evacuated, and nitrogen was filled at a rate of 80 ml / min before heating and during heating to continuously maintain the volume of nitrogen in the furnace to create anoxic and oxygen-limited conditions. The heating rate of the vacuum tube furnace was set to 5 °C / min. A certain mass of Spartina alterniflora biochar sample was weighed into a quartz boat, placed in a high-temperature tube furnace, maintained at 300 °C, carbonized for 2 h, cooled naturally to room temperature, ground and sieved for storage. According to this step, Spartina alterniflora biochar was also prepared at 400 °C, 500 °C, and 600 °C, and the Spartina alterniflora biochar under the optimal temperature conditions was selected.

[0075] Sample testing: 1g of Spartina alterniflora biochar was put into a tea bag and hung above the food waste mixing equipment. The gas around the equipment was collected at the same time and point, and GC-IMS was used to analyze the removal of α-pineneol, limonene and ethyl acetate by different types of biochar.

[0076] Removal of main odor components of kitchen waste by biochar at different pyrolysis temperatures Figure 6 .

[0077] Experimental Example 3

[0078] In the experiment, Spartina alterniflora was selected as raw material to prepare raw biochar, which was modified with acid, alkali and oxidant. The acid solution was sulfuric acid, the alkali solution was sodium hydroxide, and the oxidant was potassium permanganate. The odor removal effect of Spartina alterniflora biochar under different modification methods was compared, and the biochar with the best modification method was screened out.

[0079] Preparation conditions: Place Spartina alterniflora in a nitrogen tube furnace, heat to 400℃ and keep for 2h for pyrolysis to obtain Spartina alterniflora biochar; take 5g of Spartina alterniflora biochar and add it to 50mL of sulfuric acid solution and stir it magnetically for 6h, dry the material in a 60℃ oven for 24h, then rinse it with deionized water 3 times to remove easily leached pollutants, and continue to dry it in a 60℃ oven for 24h to obtain acid-modified Spartina alterniflora biochar. According to this step, Spartina alterniflora biochar under alkali modification (sodium hydroxide) and oxidant modification (potassium permanganate) was also prepared.

[0080] Sample testing: 1g of modified biochar was put into a tea bag and hung above the food waste mixing equipment. The gas around the equipment was collected at the same time and point, and GC-IMS was used to analyze the removal of α-pineneol, limonene and ethyl acetate by different types of biochar.

[0081] Effect of biochar on the removal of main odor components of kitchen waste under different modification methods Figure 7 .

[0082] Experimental Example 4

[0083] Establish an olfactory identification team: The olfactory identification team is composed of more than 3 people, and the number of people is generally an odd number; the olfactory identifiers are required to have a normal sense of smell and not have symptoms such as rhinitis and colds that affect the sense of smell.

[0084] Requirements: Do not eat foods with strong odors or irritating tastes, and do not use perfume on the day of the olfactory identification.

[0085] Experimental Procedure

[0086] (1) The odorants rate the odor intensity on a scale of 0-12 according to the "Description and Instructions for Odor Intensity" (Table 1) without discussion and independently give the results and record them in a table.

[0087] (2) Omnivores judge the odor characteristics of the sample based on the odor characteristic description. More than one description is allowed for a sample, and finally a consensus is reached through group discussion.

[0088] (3) The odor description that more than 50% of the panelists can identify is recorded as the sample's odor feature. The intensity of this feature is the average of the odor intensities of all members smelling the sample. If the intensity value of this feature is not given, it will be recorded as 0.

[0089] (4) If less than 50% of the panelists identify a particular odor type, the odor description is not included as the odor characteristic of the sample and no intensity value is assigned to it.

[0090] (5) Finally, the odor intensity and odor type characteristics of the sample can be obtained. The odor description with a higher intensity value is the main odor characteristic of the sample, and the odor description with a lower intensity value is regarded as a secondary odor to be characterized.

[0091] Table 1 Description and explanation of the odor intensity of volatile odors from kitchen waste

[0092]

[0093] Sensory analysis of the removal of main odor components from kitchen waste by biochar modified with Spartina alterniflora Figure 8 .

[0094] Experimental Example 5

[0095] The Spartina alterniflora modified biochar with the best adsorption performance was selected for SEM characterization under 400℃ pyrolysis conditions. The microscopic morphology was observed and it was found that the surface of the biochar was uneven and the number of micropores was huge. The microporous structure was seen under 500 times magnification, and the porosity was high, which greatly increased the specific surface area of ​​the material and provided a large number of active sites for the attachment of the adsorbate. The material has a rich irregular pore structure. The biochar itself has the characteristics of many pores, large specific surface area, stable properties and strong cation exchange capacity, which determines that biochar has broad application prospects in the adsorption of atmospheric organic pollutants.

[0096] SEM surface morphology of Spartina alterniflora modified biochar Fig. 9 .

[0097] Experimental Example 6

[0098] The biochar modified by Spartina alterniflora was selected for infrared spectroscopy (FT-IR) and XPS analysis.

[0099] FT-IR analysis can identify functional groups on the surface of biochar, such as hydroxyl (-OH), carboxyl (-COOH), carbonyl (C=O), etc. These functional groups play a key role in the adsorption and catalysis of VOCs. For example, hydroxyl and carboxyl groups can interact with VOCs molecules (such as ethyl acetate) through hydrogen bonds or electrostatic interactions to enhance the adsorption effect. Carbonyl and aromatic ring structures may participate in the redox reaction of VOCs and promote their degradation. Nitrogen- or sulfur-containing functional groups are introduced during the biochar modification process, which can undergo specific chemical reactions with VOCs molecules to improve the removal efficiency.

[0100] Through XPS analysis, high-resolution C1s were attributed to CC, CO, and C=O. There are oxygen-containing functional groups on the carbon surface. The surface functional groups on porous carbon materials are responsible for the chemical adsorption of volatile organic compounds, among which oxygen groups are considered to be the most important species for adsorption. The surface of modified biochar may contain more oxygen-containing functional groups (such as CO and C=O), which can remove VOCs through chemical adsorption or catalysis.

[0101] FT-IR (a) and XPS (b) characterization analysis of Spartina alterniflora modified biochar Fig.10 .

[0102] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing Spartina alterniflora modified biochar, characterized in that: The following steps are involved: 1) selecting a biomass raw material and pretreating the biomass raw material to obtain dry biomass; 2) Put the dried biomass into a high-temperature tube furnace, heat it to 300-600℃ under anaerobic conditions, and carbonize it for 2 hours to pyrolyze the biomass to form biochar, cool it naturally to room temperature, grind it, sieve it, and store it for later use; 3) The biochar is immersed in an acidic solution to obtain modified biochar after treatment.

2. The method for preparing modified biochar of Spartina alterniflora according to claim 1, characterized in that: The pretreatment includes washing, removing impurities and drying the biomass.

3. The method for preparing Spartina alterniflora modified biochar according to claim 1, characterized in that: The pyrolysis conditions are as follows: nitrogen is introduced and the heating rate is 5°C / min.

4. The method for preparing Spartina alterniflora modified biochar according to claim 1, characterized in that: The acidic solution is nitric acid, hydrogen peroxide, sulfuric acid, or sulfuric acid-hydrogen peroxide.

5. The method for preparing Spartina alterniflora modified biochar according to claim 1 or 4, characterized in that: The immersion conditions are as follows: placing the mixture in a magnetic stirrer and fully vibrating and stirring for 6 h to 8 h, filtering and drying the mixture, and drying the mixture at 60° C. to 80° C. for 24 h to 48 h.

6. A Spartina alterniflora modified biochar prepared by the method according to any one of claims 1 to 5.

7. Use of the modified Spartina alterniflora biochar as claimed in claim 6 in waste treatment and environmental management.

8. The use according to claim 7, characterized in that: The application of the modified Spartina alterniflora biochar in removing odorous volatile organic compounds in a kitchen waste degradation device.

9. The use according to claim 8, characterized in that: The volatile organic matter includes α-terpineol, limonene and ethyl acetate.

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