A method for preparing a slow-release deodorizing material

Abstract

This invention relates to the preparation of environmental purification materials, aiming to provide a method for preparing a slow-release deodorizing material. The method includes: grinding sodium chlorite and a dispersant, dispersing the filter residue in an organic solvent to obtain a sodium chlorite dispersion; adding silver nitrate and reacting under stirring and heating; washing and filtering the reaction product to obtain nano-silver modified sodium chlorite; dissolving ethyl cellulose in an organic solvent, adding the nano-silver modified sodium chlorite, mixing well, and then adding it dropwise to an aqueous solution of chitosan and acetic acid; reacting, heating and stirring, filtering, and drying to obtain the slow-release deodorizing material. The deodorizing material particles prepared by this invention can be stacked at intervals or dispersed in a solvent to form a spray product for spraying. Then, in conjunction with the use of external acidic liquids, a reaction occurs, releasing chlorine dioxide to dissolve ammonia and hydrogen sulfide generated in the site, thereby achieving application in the field of waste deodorization.

Description

Technical Field

[0001] This invention relates to the preparation of environmental purification materials, and particularly to a method for preparing a slow-release deodorizing material. Background Technology

[0002] Currently, landfills and leachate treatment sites produce malodorous gases such as ammonia and hydrogen sulfide due to the easy decomposition and fermentation of organic compounds (e.g., proteins, amino acids) in kitchen waste, which contain nitrogen and sulfur. This affects the lives of nearby residents. Spraying deodorizers is a relatively economical and convenient technical solution for effectively eliminating odors. Suitable deodorizers can be mainly divided into masking deodorizers, biological deodorizers, and chemically reactive deodorizers. Plant-based deodorizers mostly use the masking effect of fragrances and other odor compounds to reduce the discomfort caused by odors, but they do not have the ability to remove odor components. Biological deodorizers mainly use microorganisms or enzymes to catalyze the degradation of odor components, but require strict control of environmental temperature and humidity, making their application conditions relatively harsh. Chemically reactive deodorizers utilize the active ingredients in the deodorizer to react chemically with odor molecules to reduce odor concentration, and are currently the mainstream application. Among many chemically reactive deodorizers, chlorine dioxide has been widely studied and applied due to its outstanding advantages of high efficiency, safety, and environmental friendliness. The typical application method involves preparing a sodium chlorite aqueous solution on-site, then reacting it with acid to obtain a chlorine dioxide aqueous solution. However, the stability of the chlorine dioxide aqueous solution is poor, significantly reducing its service life and application effectiveness. Therefore, slow-release chlorine dioxide deodorizers have become a research hotspot.

[0003] Currently, there are two main technical approaches for preparing chlorine dioxide slow-release deodorizers: One approach involves using a porous carrier to adsorb chlorine dioxide, achieving a slow release. However, adsorbed solid chlorine dioxide slow-release agents have poor release performance and are difficult to control, being greatly affected by external conditions. The second approach involves treating the precursors that generate chlorine dioxide (mainly sodium chlorite), relying on slowing down or controlling the reaction between sodium chlorite and acid to achieve slow release. Currently, these slow-release materials are mainly made into gels and films, finding applications in applications such as placement-type air purification and packaging, but their use is still rare in areas such as garbage deodorizing sprays.

[0004] Furthermore, the on-site environment in the field of waste deodorization is quite complex, which places higher demands on the deodorization performance of chlorine dioxide slow-release materials. Therefore, there is an urgent need to develop a high-performance slow-release deodorization material based on chlorine dioxide suitable for waste deodorization. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for preparing a slow-release deodorizing material.

[0006] To solve the above-mentioned technical problems, the solution of the present invention is:

[0007] A method for preparing a slow-release deodorizing material is provided, comprising the following steps:

[0008] (1) Take 1 part by mass of sodium chlorite, 0.01 to 0.1 parts by mass of dispersant and 5 to 10 parts by mass of organic solvent A, add them to the feed cylinder and stir; pour the obtained slurry into the sand mill jar of the sand mill for sanding treatment; after sand milling treatment, filter the slurry to obtain filter residue, and disperse it in organic solvent B at a concentration of 5% by mass to obtain sodium chlorite dispersion;

[0009] (2) Add 0.05 to 0.5 parts by mass of silver nitrate to 1 part by mass of sodium chlorite dispersion, and react for 0.5 to 3 hours under stirring and water bath conditions of 60 to 90°C; the reaction product is washed with anhydrous ethanol and filtered to obtain nano-silver modified sodium chlorite.

[0010] (3) Dissolve 1 part by mass of ethyl cellulose in 30-50 parts by mass of organic solvent C, then add the nano-silver modified sodium chlorite prepared in step (2), mix well to obtain mixture A; dissolve 0.5-1 part by mass of chitosan in 80-100 parts by mass of acetic acid aqueous solution with a mass fraction of 2-5% to obtain mixture B; add mixture A dropwise to mixture B under stirring, react for 30-90 min; then continue stirring for 2-5 h under 70℃ water bath conditions, filter and dry to obtain slow-release deodorizing material.

[0011] As a preferred embodiment of the present invention, the dispersant mentioned in step (1) is at least one of polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, and sodium laurylate.

[0012] As a preferred embodiment of the present invention, the organic solvent A mentioned in step (1) is at least one of propylene glycol methyl ether, ethanol, and isopropanol.

[0013] As a preferred embodiment of the present invention, the organic solvent B mentioned in step (1) is at least one of ethanol and isopropanol.

[0014] As a preferred embodiment of the present invention, the stirring rate in step (1) is 1000 r / min and the stirring time is 30 to 90 min.

[0015] As a preferred embodiment of the present invention, the rotation speed of the grinding head in the grinding jar in step (1) is 800-1500 r / min, the abrasive used is zirconium beads with a particle size of 0.1-0.5 mm, the temperature inside the jar is 25-35℃, and the processing time is 4-8 h.

[0016] As a preferred embodiment of the present invention, the slurry after sand milling in step (1) is filtered sequentially with 5000 mesh and 10000 mesh filter cloths to obtain filter residue with a sieve aperture of less than 5000 mesh and greater than 10000 mesh.

[0017] As a preferred embodiment of the present invention, in step (3), the mixture A is added dropwise to the mixture B at a rate of 2 ml / min under a stirring rate of 1200 r / min; and the mixture is continuously stirred at a rate of 100 r / min under water bath conditions.

[0018] As a preferred embodiment of the present invention, the organic solvent C mentioned in step (3) is at least one of dichloromethane, methanol, and acetone.

[0019] The present invention further provides a method for using the aforementioned slow-release deodorizing material, characterized in that the powder of the slow-release deodorizing material is filled into a box with ventilation holes or a breathable cloth bag, and a 5% mass fraction of citric acid aqueous solution is sprayed onto the surface of the material to ensure saturation; then multiple filled boxes or cloth bags are placed alternately in a landfill or leachate treatment site to achieve deodorization by dissolving the ammonia and hydrogen sulfide generated in the site.

[0020] The implementation principle of this invention:

[0021] 1. This invention uses ball milling and two-stage filtration to prepare sodium chlorite particles with a narrow size distribution. By using a surface dispersant on the sodium chlorite particles to bind silver ions, sites for the growth of silver nanoparticles in the subsequent hot ethanol solvent are constructed, achieving uniform loading of silver nanoparticles on the surface of the sodium chlorite particles.

[0022] 2. This invention disperses nano-silver modified sodium chlorite particles in an organic solvent of ethyl cellulose to form an oil phase; dissolves chitosan in an aqueous acetic acid solution to form an aqueous phase; under high-speed stirring, the oil phase is emulsified into the aqueous phase to form an oil-in-water emulsion. Heating promotes the preferential evaporation of the low-boiling-point solvent in the oil phase, while the water-insoluble ethyl cellulose forms a porous shell coating the surface of the nano-silver modified sodium chlorite particles. During use, additional external acidic liquid can slowly penetrate into the interior through the porous shell and react with the sodium chlorite particles, thereby releasing chlorine dioxide to oxidize and remove odors. Furthermore, the nano-silver inside the shell also releases silver ions, killing microorganisms that cause the decomposition and fermentation of kitchen waste in the environment, thus reducing odor generation at the source.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. Compared with traditional slow-release materials in the form of gels and films, the deodorizing material prepared by this invention is in the form of micron-sized slow-release particles, which can be dispersed in solvents to form spray products for spraying, or stacked at intervals in landfills or leachate treatment sites; then reacting with the use of external acidic liquids, releasing chlorine dioxide to dissolve ammonia and hydrogen sulfide generated in the site, thereby realizing its application in the field of waste deodorization.

[0025] 2. The slow-release deodorizing material prepared by this invention has both active and passive deodorizing functions: on the one hand, it can kill microorganisms through silver ions, reducing the generation of odors at the source; on the other hand, it can oxidize and decompose existing odors through the slow release of chlorine dioxide. Therefore, it has a more efficient and longer-lasting deodorizing ability. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to specific embodiments.

[0027] The preparation method of the slow-release deodorizing material of the present invention includes the following steps:

[0028] (1) Take 1 part by mass of sodium chlorite, 0.01-0.1 parts by mass of dispersant and 5-10 parts by mass of organic solvent A, add them to the mixing tank and stir at a speed of 1000 r / min for 30-90 min. Pour the obtained slurry into the sand mill jar of a sand mill for sand milling treatment; the rotation speed of the grinding head in the sand mill jar is 800-1500 r / min, and the abrasive used is zirconium beads with a particle size of 0.1-0.5 mm; the temperature inside the jar is 25-35℃, and the treatment time is 4-8 h. The slurry after sand milling treatment is filtered through 5000 mesh and 10000 mesh filter cloths in sequence to obtain filter residue with a sieve aperture of less than 5000 mesh and greater than 10000 mesh. Disperse it in organic solvent B at a mass fraction of 5% to obtain sodium chlorite dispersion.

[0029] The dispersant is at least one selected from polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, and sodium laurate. Organic solvent A is at least one selected from propylene glycol methyl ether, ethanol, and isopropanol. Organic solvent B is at least one selected from ethanol and isopropanol.

[0030] (2) Add 0.05 to 0.5 parts by mass of silver nitrate to 1 part by mass of sodium chlorite dispersion, and react for 0.5 to 3 hours under stirring and water bath conditions of 60 to 90°C; the reaction product is washed with anhydrous ethanol and filtered to obtain nano-silver modified sodium chlorite.

[0031] (3) Dissolve 1 part by mass of ethyl cellulose in 30-50 parts by mass of organic solvent C, wherein organic solvent C is at least one of dichloromethane, methanol, and acetone. Then add the nano-silver modified sodium chlorite prepared in step (2), mix well to obtain mixture A; dissolve 0.5-1 part by mass of chitosan in 80-100 parts by mass of 2-5% aqueous acetic acid solution to obtain mixture B; add mixture A dropwise to mixture B at a rate of 2 ml / min under a stirring rate of 1200 r / min, and react for 30-90 min; then stir continuously at a rate of 100 r / min for 2-5 h under a water bath at 70℃, filter, and dry to obtain a slow-release deodorizing material. The product is in the form of a dispersed powder.

[0032] In practical use, the slow-release deodorizing material powder is filled into a ventilated box or breathable cloth bag. A 5% (by mass) citric acid aqueous solution is sprayed onto the material surface, ensuring complete saturation. Multiple filled boxes or bags are then placed alternately in the landfill or leachate treatment site. Deodorization is achieved by slowly releasing chlorine dioxide to dissolve ammonia and hydrogen sulfide generated within the site. Alternatively, the deodorizing material powder can be dispersed in a solvent to form a spray product for application in the landfill or leachate treatment site. This product then reacts with external acidic liquids to slowly release chlorine dioxide.

[0033] The following embodiments are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way. Slow-release deodorizing materials were successfully prepared through eight embodiments, and the experimental data for each embodiment are shown in Table 1 below.

[0034] Table 1. Data Table for Embodiments

[0035]

[0036]

[0037] Test methods for slow-release deodorizing materials:

[0038] (1) Experimental materials and apparatus

[0039] A sample cell measuring 45cm × 45cm; a glove box measuring 60cm × 60cm × 80cm with a downward-blowing fan on top; a gas injector; and a Riken GX-6000 gas detector from Japan.

[0040] (2) Test Procedure

[0041] ① The slow-release deodorizing material is placed in the sample cell. A 5% (by mass) citric acid aqueous solution, equal in mass to the material, is sprayed onto the surface of the material. This solution slowly penetrates through the porous shell of the slow-release deodorizing material and reacts with the sodium chlorite particles encapsulated inside, thereby releasing chlorine dioxide. The sample cell is then placed in a glove box, which is sealed. A certain amount of target gas is injected into the glove box using a gas sampler, maintaining the initial concentration of the target gas in the glove box at a certain value a0 (approximately 200 ppm for ammonia and approximately 50 ppm for hydrogen sulfide).

[0042] ② Turn on the fan and direct it towards the sample cell. After the reaction has been going on for 2 hours, test the concentration 'a' of the target gas inside the glove box. t The target gas removal rate P can be calculated using the following formula, which characterizes the purification performance of the slow-release deodorizing material.

[0043]

[0044] ③ The test of the 10-day removal rate of the target gas is to soak the slow-release deodorizing material in a 5% (w / w) citric acid aqueous solution for 10 days, and then conduct the test according to steps ① and ② above.

[0045] The data on purification performance are shown at the end of Table 1.

[0046] Comparison with existing slow-release deodorizing materials:

[0047] Under the same test conditions, the ammonia removal rate of existing commercially available gel-type slow-release chlorine dioxide products is 84.2% and the hydrogen sulfide removal rate is 78.5%, while the ammonia removal rate after 10 days is 44.7% and the hydrogen sulfide removal rate after 10 days is 37.7%. Therefore, it can be seen that the purification performance of the slow-release deodorizing materials prepared in each embodiment of the present invention is superior to that of existing commercially available gel-type slow-release chlorine dioxide products.

[0048] Finally, it should be noted that the above examples are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this invention should be considered within the scope of protection of this invention.

Claims

1. A method for preparing a slow-release deodorizing material, characterized in that, Includes the following steps: (1) Take 1 part by weight of sodium chlorite, 0.01~0.1 parts by weight of dispersant and 5~10 parts by weight of organic solvent A, add them to the material barrel and stir; The obtained slurry is poured into the grinding jar of a sand mill for grinding treatment; the rotation speed of the grinding head in the grinding jar is 800~1500 r / min, and the abrasive used is zirconium beads with a particle size of 0.1~0.5 mm; the temperature inside the jar is 25~35℃, and the treatment time is 4~8h; after the sand milling treatment, the slurry is filtered to obtain filter residue, and then dispersed in organic solvent B at a mass fraction of 5% to obtain sodium chlorite dispersion; (2) Add 0.05~0.5 parts by mass of silver nitrate to 1 part by mass of sodium chlorite dispersion, and react for 0.5~3 h under stirring and 60~90℃ water bath conditions; the reaction product is washed with anhydrous ethanol and filtered to obtain nano-silver modified sodium chlorite. (3) Dissolve 1 part by mass of ethyl cellulose in 30-50 parts by mass of organic solvent C, then add the nano-silver modified sodium chlorite prepared in step (2), mix well to obtain mixture A; dissolve 0.5-1 part by mass of chitosan in 80-100 parts by mass of 2-5% aqueous acetic acid solution to obtain mixture B; add mixture A dropwise to mixture B at a stirring rate of 2 ml / min at a stirring rate of 1200 r / min; stir continuously at a rate of 100 r / min under water bath conditions for 30-90 min; then stir continuously under water bath conditions of 70℃ for 2-5 h, filter and dry to obtain slow-release deodorizing material.

2. The preparation method according to claim 1, characterized in that, The dispersant mentioned in step (1) is at least one of polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, and sodium laurylate.

3. The preparation method according to claim 1, characterized in that, The organic solvent A mentioned in step (1) is at least one of propylene glycol methyl ether, ethanol, and isopropanol.

4. The preparation method according to claim 1, characterized in that, The organic solvent B mentioned in step (1) is at least one of ethanol and isopropanol.

5. The preparation method according to claim 1, characterized in that, The stirring rate in step (1) is 1000 r / min, and the stirring time is 30~90 min.

6. The preparation method according to claim 1, characterized in that, In step (1), the slurry after sand milling is filtered sequentially with 5000 mesh and 10000 mesh filter cloths to obtain filter residue with a sieve aperture of less than 5000 mesh and greater than 10000 mesh.

7. The preparation method according to claim 1, characterized in that, The organic solvent C mentioned in step (3) is at least one of dichloromethane, methanol, and acetone.

8. A method of using the slow-release deodorizing material prepared by the preparation method according to any one of claims 1 to 7, characterized in that, The slow-release deodorizing material powder is filled into a box with ventilation holes or a breathable cloth bag, and a 5% citric acid aqueous solution of equal mass fraction is sprayed onto the material surface to ensure saturation. Then, multiple filled boxes or cloth bags are placed alternately in a landfill or leachate treatment site to achieve deodorization by dissolving the ammonia and hydrogen sulfide generated in the site.

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