Preparation method of biomass-based nano-carbon deodorant

Abstract

The present application belongs to the field of preparation of deodorizing materials, and particularly relates to a preparation method of a nano-carbon deodorant for removing malodorous substances. The method first prepares a precursor by low-temperature pyrolysis of defatted rice straw; then obtains a nano-carbon aqueous solution through low-temperature hydrothermal reaction; and finally obtains the final product by freeze-drying technology. The nano-carbon deodorant has good deodorizing effect, the raw material of the nano-carbon is biomass rice straw, no high temperature and high pressure are required in the experiment process, the waste is realized as a resource, the energy consumption is reduced, the preparation cost of the nano-carbon is reduced, and the process is simple, controllable, safe, environmentally friendly, and has large-scale production potential.

Description

Technical Field

[0001] This invention belongs to the field of deodorizing material preparation, specifically relating to a method for preparing a nano-carbon deodorizer for removing malodorous substances. Background Technology

[0002] In recent years, the rise of nanotechnology has led to the significant development of nanocarbon materials. Due to their unique structure and high biocompatibility, nanocarbon is widely used in many fields such as adsorption, catalysis, electrochemistry, agriculture, medicine, and energy storage. In the adsorption field, biochar adsorbents have an adsorption capacity of 0.0018 mg / g for CO2, while nitrogen-rich nanocarbon adsorbents have an adsorption capacity of 186.12 mg / g for CO2. Nanocarbon adsorbents are effective against organic pollutants and heavy metal ions in water, such as phenols, organic dyes, and chromium. 6+ The adsorption capacities of these nanocarbons were also high, with adsorption capacities of 540.4 mg / g, 10.36 mg / g, and 336.7 mg / g, respectively. This demonstrates the significant potential of nanocarbon adsorbents in adsorption. Traditional nanocarbon preparation utilizes hydrothermal synthesis, but the resulting nanocarbons have small specific surface areas and poor adsorption performance. High-temperature activation pyrolysis requires activators such as KOH, FeCl3, and AlCl3, increasing costs and energy consumption. Template methods have high requirements for templates, and the template removal process is complex, making industrial scale-up difficult. Therefore, it is necessary to develop a low-energy, low-cost, simple, and environmentally friendly method for preparing highly adsorbent nanocarbons.

[0003] The following are some references regarding research on nano-carbon.

[0004] Chinese Patent 202111322654.2

[0005] Chinese Patent 202110544773.6

[0006] Chinese Patent 202010305033.2

[0007] Chinese Patent 202210074982.3

[0008] Chinese Patent 202210502979.7

[0009] Chinese Patent 202010305033.2

[0010] Chinese Patent 201910117866.3

[0011] Chinese Patent 201911067630.X

[0012] Chinese Patent 201810237978.8

[0013] Adsorption of organic pollutants in water by biomass nanocarbon materials. 2022, 38(8):11-14.

[0014] Review on recent advances of carbon based adsorbent for methyleneblue removal from waste water. 2020, 16: 100233.

[0015] Nanocarbons in different structural dimensions (0–3D) for phenoladsorption and metal-free catalytic oxidation. 2015, 179: 352-362. Summary of the Invention

[0016] The purpose of this invention is to overcome the shortcomings of existing nano-carbon adsorbent preparation and large-scale production, and to provide a method for preparing nano-carbon adsorbents at low temperature using rice straw as raw material without the addition of drugs. This method has a simple process, low preparation cost, good deodorization effect, realizes the resource utilization of waste, and is suitable for industrial-scale production.

[0017] To achieve the above objectives, the preparation method of the present invention includes a process of preparing a low-temperature pyrolysis precursor and preparing low-temperature hydrothermal nanocarbon, and consists of the following steps:

[0018] Step 1: Crush rice straw to 60 mesh, take 4g of straw powder into a Soxhlet extractor, and add 75 mL of solvent (V 乙醇 V 甲苯 = 1:2), defatted at 160℃ for 5 h, cooled to room temperature, washed with ethanol until no toluene residue was found, dried at 60℃ for 3 h, and then 3 g of defatted straw was placed in a tube furnace and pyrolyzed in a N2 atmosphere at 100~200℃ for 1~3 h. After natural cooling, the hydrothermal precursor was obtained.

[0019] Step 2: Add 2 g of hydrothermal precursor and distilled water to the reactor and hydrothermally heat for 10 h. After cooling to room temperature, remove the reactor.

[0020] Step 3: Pour the hydrothermal solution into the dialysis bag, place it in deionized water for dialysis, change the water every 8 hours, and dialysis for 72 hours;

[0021] Step 4: The hydrothermal solution after dialysis is filtered through a microporous membrane (pore size 220 nm) to obtain a yellow nano-carbon aqueous solution;

[0022] Step 5: Pour the nano-carbon aqueous solution into a petri dish and freeze it in a refrigerator until the liquid turns into a solid. Then, freeze-dry it in a freeze dryer to obtain dark brown nano-carbon.

[0023] In step one, the heating rate of the pyrolysis process is 5℃ / min;

[0024] In step two, the volume of distilled water is 60 mL, the volume of the reaction vessel is 150 mL, and the hydrothermal temperature is 170℃.

[0025] In step three, the dialysis bag has a molecular weight cutoff of 1000.

[0026] The advantages of this invention are as follows:

[0027] 1. Using waste biomass rice straw as raw material greatly reduces the preparation cost of nano-carbon adsorbents, realizes the resource utilization of waste, has little environmental pollution, and meets environmental protection requirements;

[0028] 2. Low-temperature pyrolysis and low-temperature hydrothermal methods can achieve low energy consumption, low cost, green and pollution-free operation, and simple operation, making them suitable for industrial-scale production;

[0029] 3. Biomass-based nano-carbon adsorbents have good deodorization effects, are easy to transport, and are suitable for industrial promotion. Attached Figure Description

[0030] Figure 1 The images show the H2S adsorption curve and SEM image of a biomass-based nano-charcoal deodorant prepared in Example 1 of this invention.

[0031] Figure 2 The images show the H2S adsorption curve and SEM image of a biomass-based nano-charcoal deodorant prepared in Example 2 of this invention. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to embodiments:

[0033] A method for preparing a biomass-based nano-carbon deodorizer, characterized by: low-temperature pyrolysis precursor preparation and low-temperature hydrothermal nano-carbon preparation, comprising the following steps:

[0034] Step 1: Crush rice straw to 60 mesh, take 4g of straw powder into a Soxhlet extractor, and add 75 mL of solvent (V 乙醇 V 甲苯 = 1:2), defatted at 160℃ for 5 h, cooled to room temperature, washed with ethanol until no toluene residue was found, dried at 60℃ for 3 h, and then 3 g of defatted straw was placed in a tube furnace and pyrolyzed in a N2 atmosphere at 100~200℃ for 1~3 h. After natural cooling, the hydrothermal precursor was obtained.

[0035] Step 2: Add 2 g of hydrothermal precursor and distilled water to the reactor and hydrothermally heat for 10 h. After cooling to room temperature, remove the reactor.

[0036] Step 3: Pour the hydrothermal solution into the dialysis bag, place it in deionized water for dialysis, change the water every 8 hours, and dialysis for 72 hours;

[0037] Step 4: The hydrothermal solution after dialysis is filtered through a microporous membrane (pore size 220 nm) to obtain a yellow nano-carbon aqueous solution;

[0038] Step 5: Pour the nano-carbon aqueous solution into a petri dish and freeze it in a refrigerator until the liquid turns into a solid. Then, freeze-dry it in a freeze dryer to obtain dark brown nano-carbon.

[0039] In step one, the heating rate of the pyrolysis process is 5℃ / min;

[0040] In step two, the volume of distilled water is 60 mL, the volume of the reaction vessel is 150 mL, and the hydrothermal temperature is 170℃.

[0041] In step three, the dialysis bag has a molecular weight cutoff of 1000.

[0042] Example 1

[0043] Crush rice straw to 60 mesh. Take 4g of straw powder into a Soxhlet extractor and add 75 mL of solvent (V). 乙醇 V 甲苯 = 1:2), defatted at 160℃ for 5 h, cooled to room temperature, washed with ethanol until no toluene residue was found, dried at 60℃ for 3 h, then 3 g of defatted straw was placed in a tube furnace and pyrolyzed at 150℃ under N2 atmosphere for 1 h, and naturally cooled to obtain a hydrothermal precursor; 2 g of hydrothermal precursor and 60 mL of distilled water were placed in a reaction vessel and hydrothermally heated at 170℃ for 10 h, and then cooled to room temperature; the hydrothermal solution was poured into a dialysis bag and dialyzed in deionized water, with the water changed every 8 h, for 72 h; after dialysis, the hydrothermal solution was filtered through a microporous membrane (pore size 220 nm) to obtain a yellow nano-carbon aqueous solution; this was poured into a petri dish and frozen until the liquid completely turned into a solid, then freeze-dried in a freeze dryer to obtain dark brown nano-carbon; 0.01 g of nano-carbon was placed in an adsorption detection tube and connected to a gas chromatograph, when the H2S inlet gas concentration was 100.0 ppm, space velocity of 15591 h -1 When the gas concentration does not exceed 20.0 ppm, the adsorption time of this product for H2S is 55 min.

[0044] like Figure 1The image shows the H2S adsorption curve and SEM image of the biomass-based nano-char deodorizer prepared in Example 1 of this invention. It can be observed that the nano-char deodorizer was successfully prepared and the H2S adsorption time was 55 min.

[0045] Example 2

[0046] Crush rice straw to 60 mesh. Take 4g of straw powder into a Soxhlet extractor and add 75 mL of solvent (V). 乙醇 V 甲苯 = 1:2), defatted at 160℃ for 5 h, cooled to room temperature, washed with ethanol until no toluene residue was found, dried at 60℃ for 3 h, then 3 g of defatted straw was placed in a tube furnace and pyrolyzed at 200℃ under N2 atmosphere for 3 h, and naturally cooled to obtain a hydrothermal precursor; 2 g of hydrothermal precursor and 60 mL of distilled water were placed in a reaction vessel and hydrothermally heated at 170℃ for 10 h, and then cooled to room temperature; the hydrothermal solution was poured into a dialysis bag and dialyzed in deionized water, with the water changed every 8 h, for 72 h; after dialysis, the hydrothermal solution was filtered through a microporous membrane (pore size 220 nm) to obtain a yellow nano-carbon aqueous solution; this was poured into a petri dish and frozen until the liquid completely turned into a solid, then freeze-dried in a freeze dryer to obtain dark brown nano-carbon; 0.01 g of nano-carbon was placed in an adsorption detection tube and connected to a gas chromatograph, when the H2S inlet gas concentration was 100.0 ppm, space velocity of 15591 h -1 When the gas concentration does not exceed 20.0 ppm, the adsorption time of this product for H2S is 85 min.

[0047] like Figure 2 The image shows the H2S adsorption curve and SEM image of the biomass-based nano-carbon deodorizer prepared in Example 2 of this invention. It can be observed that the nano-carbon deodorizer was successfully prepared and the H2S adsorption time was 85 min.

Claims

1. A method for preparing a biomass-based nano-carbon deodorizer, the method comprising the preparation processes of a precursor and nano-carbon, and the entire preparation method consisting of the following steps: Step 1: Crush rice straw to 60 mesh, take 4g of straw powder into a Soxhlet extractor, add 75mL of solvent (the solvent is composed of ethanol and toluene in a volume ratio of 1:2), defatt the straw at 160℃ for 5h, cool to room temperature, wash the sample with ethanol until no toluene residue remains, dry at 60℃ for 3h, then take 3g of defatted straw into a tube furnace and pyrolyze it in a N2 atmosphere at 100-200℃ for 1-3h, and obtain the hydrothermal precursor after natural cooling; Step 2: Add 2g of hydrothermal precursor and distilled water to the reaction vessel and hydrothermally heat for 10 hours. After cooling to room temperature, remove the mixture. Step 3: Pour the hydrothermal solution into the dialysis bag, place it in deionized water for dialysis, change the water every 8 hours, and dialysis for 72 hours; Step 4: The hydrothermal solution after dialysis is filtered through a microporous membrane with a pore size of 220 nm to obtain a yellow nano-carbon aqueous solution; Step 5: Pour the nano-carbon aqueous solution into a petri dish and freeze it in a refrigerator until the liquid turns into a solid. Then, freeze-dry it in a freeze dryer to obtain dark brown nano-carbon.

2. The method for preparing the nano-carbon deodorant according to claim 1, characterized in that: The heating rate in step one of the pyrolysis process is 5℃ / min.

3. The method for preparing the nano-carbon deodorant according to claim 1, characterized in that: The volume of distilled water mentioned in step two is 60 mL, the volume of the reaction vessel is 150 mL, and the hydrothermal temperature is 170 °C.

4. The method for preparing the nano-carbon deodorant according to claim 1, characterized in that: The dialysis bag described in step three has a molecular weight cutoff of 1000.

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