Preparation method of slow-release deodorization material

Abstract

The invention relates to preparation of an environment purification material, and aims to provide a preparation method of a slow-release deodorization material. Comprising the following steps: grinding sodium chlorite and a dispersing agent, and dispersing filter residues into an organic solvent to obtain a sodium chlorite dispersion liquid; continuing to add silver nitrate, and reacting under stirring and heating; washing and filtering a reaction product to obtain nano-silver modified sodium chlorite; dissolving ethyl cellulose in an organic solvent, adding nano-silver modified sodium chlorite, uniformly mixing, continuously dropwise adding into an acetic acid aqueous solution of chitosan, reacting, heating, stirring, filtering, and drying to obtain the slow-release deodorizing material. The prepared deodorization material particles can be stacked at intervals and can also be dispersed into a solvent to form a spray product for spraying, then the spray product is combined with external acid liquid to react, and ammonia gas and hydrogen sulfide generated in a place are digested by releasing chlorine dioxide, so that the application in the field of garbage deodorization is realized.

Description

Technical Field

[0001] The invention relates to the preparation of an environment purification material, and in particular to a method for preparing a slow-release deodorizing material. Background Art

[0002] At present, landfills and leachate treatment sites produce foul-smelling gases such as ammonia and hydrogen sulfide due to the easy decay and fermentation of organic compounds such as nitrogen and sulfur (such as proteins and amino acids) in kitchen waste, which affects the lives of surrounding residents. Spraying deodorants is a relatively economical and convenient technical solution to effectively eliminate odors. The types of deodorants suitable for spraying are mainly divided into masking deodorants, biological deodorants and chemical reaction deodorants. Among them, plant-based deodorants mostly use the masking effect of odor compounds such as flavors to reduce the discomfort caused by odors, and have no ability to remove odor components; biological deodorants mainly use microorganisms or biological enzymes to catalyze the degradation of odor components, but require strict control of environmental temperature / humidity, and the application conditions are relatively harsh; chemical reaction deodorants use the active ingredients in the deodorant to react chemically with odor molecules to reduce the odor concentration, which is the mainstream of current applications. Among many chemically reactive deodorants, chlorine dioxide has been widely studied and applied due to its outstanding advantages of high efficiency, safety and environmental friendliness. Its typical application method is to prepare sodium chlorite aqueous solution on site, and then add acid to react with sodium chlorite to obtain chlorine dioxide aqueous solution, but the stability of chlorine dioxide aqueous solution is poor, which greatly reduces the service life and application effect. Therefore, chlorine dioxide slow-release deodorant has become a research hotspot.

[0003] At present, there are two main technical solutions for preparing chlorine dioxide slow-release deodorants: one is to use a porous carrier to adsorb chlorine dioxide to achieve the slow release of chlorine dioxide. However, the sustained-release effect of adsorbed solid chlorine dioxide slow-release agents is poor, difficult to control, and greatly affected by external conditions. The second is to treat the precursor (mainly sodium chlorite) that produces chlorine dioxide, and rely on slowing down or controlling the reaction between sodium chlorite and acid to achieve the slow release of chlorine dioxide. At present, this type of slow-release material is mainly made into gels, films, etc., and is used in the fields of placement air purification, packaging, etc., but is rarely used in the fields of garbage deodorant sprays.

[0004] In addition, the on-site environment in the field of garbage deodorization is relatively complex, and higher requirements are also placed on the deodorization performance of chlorine dioxide slow-release materials. Therefore, it is urgent to develop a high-performance slow-release deodorization material based on chlorine dioxide that is suitable for the field of garbage deodorization. Summary of the invention

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

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

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

[0008] (1) 1 part by mass of sodium chlorite, 0.01 to 0.1 parts by mass of a dispersant, and 5 to 10 parts by mass of an organic solvent A are added into a barrel and stirred; the obtained slurry is poured into a sand mill tank of a sand mill for sand grinding; the sand milled slurry is filtered to obtain a filter residue, which is dispersed in an organic solvent B at a concentration of 5% by mass to obtain a sodium chlorite dispersion;

[0009] (2) adding 0.05 to 0.5 parts by weight of silver nitrate to 1 part by weight of sodium chlorite dispersion, and reacting for 0.5 to 3 hours under stirring and 60 to 90° C. water bath conditions; washing the reaction product with anhydrous ethanol and filtering to obtain nanosilver-modified sodium chlorite;

[0010] (3) dissolving 1 part by mass of ethyl cellulose in 30 to 50 parts by mass of an organic solvent C, then adding the nanosilver-modified sodium chlorite prepared in step (2), and mixing to obtain a mixed solution A; dissolving 0.5 to 1 part by mass of chitosan in 80 to 100 parts by mass of an acetic acid aqueous solution having a mass fraction of 2 to 5%, to obtain a mixed solution B; adding the mixed solution A dropwise to the mixed solution B under stirring, and reacting for 30 to 90 minutes; then continuously stirring for 2 to 5 hours in a 70° C. water bath, filtering, and drying to obtain a sustained-release deodorant material.

[0011] As a preferred embodiment of the present invention, the dispersant in step (1) is at least one of polyvinyl pyrrolidone, sodium dodecylbenzene sulfonate and sodium laurate.

[0012] As a preferred embodiment of the present invention, the organic solvent A 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 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 sand mill tank 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 in the tank is 25-35°C, and the processing time is 4-8 hours.

[0016] As a preferred embodiment of the present invention, the slurry after sand milling in step (1) is filtered with filter cloths of 5000 mesh and 10000 mesh in turn to obtain filter residues with sieve openings smaller than 5000 mesh and larger than 10000 mesh.

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

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

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

[0020] The implementation principle of the present invention:

[0021] 1. The present invention adopts a ball milling process and a two-stage filtration method to prepare sodium chlorite particles with a narrow size distribution range. Through the combination of a dispersant on the surface of the sodium chlorite particles with silver ions, a site for the subsequent growth of nanosilver in a hot ethanol solvent is constructed, and the uniform loading of nanosilver on the surface of the sodium chlorite particles is achieved.

[0022] 2. The present invention disperses the nano-silver modified sodium chlorite particles into an organic solvent of ethyl cellulose to form an oil phase; dissolves chitosan into an acetic acid aqueous 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, and the low-boiling point solvent in the oil phase is preferentially evaporated by heating, and the water-insoluble ethyl cellulose forms a porous shell layer to coat the surface of the nano-silver modified sodium chlorite particles. When in use, the additionally added external acidic liquid can slowly penetrate into the interior through the porous shell layer to react with the sodium chlorite particles, thereby releasing chlorine dioxide and achieving oxidative removal of odors. In addition, the nano-silver inside the spherical shell will also release silver ions, killing microorganisms in the environment that cause the rotting and fermentation of kitchen waste, thereby reducing the generation of odors at the source.

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

[0024] 1. Compared with the traditional sustained-release materials in the form of gels, films, etc., the deodorizing material prepared by the present invention is in the form of micron-sized sustained-release particles, which can be dispersed in a solvent to form a spray product for spraying, or stacked at intervals in a landfill or leachate treatment site; then combined with the use of an external acidic liquid to react, the ammonia and hydrogen sulfide generated in the chlorine dioxide digestion site are released, thereby realizing the application in the field of garbage deodorization.

[0025] 2. The slow-release deodorizing material prepared by the present invention has active and passive deodorizing functions: on the one hand, it can kill microorganisms by silver ions, thus reducing the generation of odor from the source; on the other hand, it can oxidize and decompose the generated odor by slow-release chlorine dioxide. Therefore, it has a more efficient and lasting deodorizing ability. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with specific implementation modes.

[0027] The method for preparing the sustained-release deodorant material of the present invention comprises 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 into a barrel and stir at a stirring rate of 1000 r / min for 30-90 min. Pour the obtained slurry into the sand mill of a sand mill for sanding treatment; the rotation speed of the grinding head in the sand mill is 800-1500 r / min, and the abrasive used is zirconium beads with a particle size of 0.1-0.5 mm; the temperature in the tank is 25-35°C, and the treatment time is 4-8 h. The slurry after sand milling is filtered with 5000 mesh and 10000 mesh filter cloths in turn to obtain a filter residue with a sieve opening smaller than 5000 mesh and larger than 10000 mesh, which is dispersed in an organic solvent B at a concentration of 5% by mass to obtain a sodium chlorite dispersion;

[0029] Wherein, the dispersant is at least one of polyvinyl pyrrolidone, sodium dodecylbenzene sulfonate and sodium laurate. The organic solvent A is at least one of propylene glycol methyl ether, ethanol and isopropanol. The organic solvent B is at least one of ethanol and isopropanol.

[0030] (2) adding 0.05 to 0.5 parts by weight of silver nitrate to 1 part by weight of sodium chlorite dispersion, and reacting for 0.5 to 3 hours under stirring and 60 to 90° C. water bath conditions; washing the reaction product with anhydrous ethanol and filtering to obtain nanosilver-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 nanosilver-modified sodium chlorite prepared in step (2), mix well to obtain a mixed solution A; dissolve 0.5-1 parts by mass of chitosan in 80-100 parts by mass of 2-5% acetic acid aqueous solution to obtain a mixed solution B; add the mixed solution A dropwise to the mixed solution B at a rate of 2 ml / min at a stirring rate of 1200 r / min, and react for 30-90 min; then continue stirring at a rate of 100 r / min for 2-5 h in a 70°C water bath, filter and dry to obtain a sustained-release deodorant material. The product is in the form of dispersed powder.

[0032] In actual use, the powder of the slow-release deodorant material is filled in a box with vents or a breathable bag, and a 5% mass fraction of citric acid aqueous solution equal to its mass is sprayed on the surface of the material to ensure that it is soaked; then multiple filled boxes or bags are placed alternately in a landfill or leachate treatment site, and deodorization is achieved by slowly releasing the ammonia and hydrogen sulfide generated in the chlorine dioxide digestion site. Alternatively, the powder of the deodorant material is dispersed in a solvent to form a spray product for spraying in a landfill or leachate treatment site, and then combined with the use of an external acidic liquid to react and slowly release chlorine dioxide.

[0033] The following examples can help professionals in this field to understand the present invention more comprehensively, but they do not limit the present invention in any way. The sustained-release deodorant materials were successfully prepared through 8 examples, and the test data in each example are shown in Table 1 below.

[0034] Table 1 Example data table

[0035]

[0036]

[0037] Test methods for sustained-release deodorant materials:

[0038] (1) Test materials and equipment

[0039] A sample pool with a size of 45cm×45cm; a glove box with a size of 60cm×60cm×80cm, with a fan blowing downwards on the top of the glove box; a gas injector; and a Japan Riken GX-6000 gas detector.

[0040] (2) Test steps

[0041] ① Place the slow-release deodorant material into the sample pool, spray a 5% mass fraction of citric acid aqueous solution on the surface of the material, so that it slowly penetrates through the porous shell of the slow-release deodorant material and reacts with the sodium chlorite particles encapsulated inside, thereby releasing chlorine dioxide. Then put the sample pool into the glove box, seal the glove box, and use a gas injector to inject a certain amount of target gas into the glove box, so that the initial concentration of the target gas in the glove box is maintained at a certain value a0 (ammonia 200ppm, hydrogen sulfide 50ppm).

[0042] ② Turn on the fan to blow air towards the sample pool. After 2 hours of reaction, test the target gas concentration a in the glove box. t ; The target gas removal rate P can be calculated by the following formula to characterize 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 immerse the slow-release deodorizing material in a 5% by mass aqueous solution of citric acid for 10 days, and then conduct the test according to the above steps ① and ②.

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

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

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

[0048] Finally, it should be noted that the above examples are only specific implementation examples of the present invention. Obviously, the present invention is not limited to the above examples, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A method for preparing a sustained-release deodorant material, characterized in that: The following steps are involved: (1) 1 part by mass of sodium chlorite, 0.01 to 0.1 parts by mass of a dispersant, and 5 to 10 parts by mass of an organic solvent A are added into a barrel and stirred; the obtained slurry is poured into a sand mill tank of a sand mill for sand grinding; the sand milled slurry is filtered to obtain a filter residue, which is dispersed in an organic solvent B at a concentration of 5% by mass to obtain a sodium chlorite dispersion; (2) adding 0.05 to 0.5 parts by weight of silver nitrate to 1 part by weight of sodium chlorite dispersion, and reacting for 0.5 to 3 hours under stirring and 60 to 90° C. water bath conditions; washing the reaction product with anhydrous ethanol and filtering to obtain nanosilver-modified sodium chlorite; (3) dissolving 1 part by mass of ethyl cellulose in 30 to 50 parts by mass of an organic solvent C, then adding the nanosilver-modified sodium chlorite prepared in step (2), and mixing to obtain a mixed solution A; dissolving 0.5 to 1 part by mass of chitosan in 80 to 100 parts by mass of an acetic acid aqueous solution having a mass fraction of 2 to 5% to obtain a mixed solution B; adding the mixed solution A dropwise to the mixed solution B under stirring, and reacting for 30 to 90 minutes; then continuously stirring for 2 to 5 hours in a 70° C. water bath, filtering, and drying to obtain a sustained-release deodorant material.

2. The method according to claim 1, characterized in that The dispersant described in step (1) is at least one of polyvinyl pyrrolidone, sodium dodecylbenzene sulfonate and sodium laurate.

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

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

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

6. The method according to claim 1, characterized in that The rotation speed of the grinding head in the sand mill tank in step (1) is 800-1500 r / min, and the abrasive used is zirconium beads with a particle size of 0.1-0.5 mm; the temperature in the tank is 25-35° C., and the processing time is 4-8 h.

7. The method according to claim 1, characterized in that The slurry after sand milling in step (1) is filtered with filter cloths of 5000 mesh and 10000 mesh in turn to obtain filter residues with sieve openings smaller than 5000 mesh and larger than 10000 mesh.

8. The method according to claim 1, characterized in that In step (3), mixed solution A is added dropwise to mixed solution B at a rate of 2 ml / min under a stirring rate of 1200 r / min; stirring is continued at a rate of 100 r / min under water bath conditions.

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

10. A method for using the sustained-release deodorant material prepared by the method according to any one of claims 1 to 9, characterized in that: The method is to fill the powder of the slow-release deodorizing material into a box with ventilation holes or a breathable cloth bag, spray a 5% mass fraction of citric acid aqueous solution equal to its mass on the surface of the material and ensure that it is soaked; then place multiple filled boxes or cloth bags alternately in a landfill or leachate treatment site to achieve deodorization by digesting the ammonia and hydrogen sulfide generated in the site.

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