A method for generating chlorine dioxide gas

Abstract

The invention discloses a method for generating chlorine dioxide gas. After mixing chlorine dioxide slow-release gel powder with water in a weight ratio of 1: (7-9), stirring into a gel state, a chlorine dioxide slow-release gel is obtained, and chlorine dioxide gas is slowly and steadily released from the chlorine dioxide slow-release gel; the chlorine dioxide slow-release gel powder includes the following weight parts: 20-40 parts of gel matrix, 1-10 parts of solid acid activator, 5-15 parts of chlorite, 1-5 parts of slow-release agent, and 1-10 parts of hygroscopic salt. The release rate of the chlorine dioxide gas generation method of the present invention is stable and controllable, avoiding a fast initial release rate and a slow later release rate.

Description

Technical Field

[0001] The invention relates to the technical field of air disinfection, and in particular to a method for generating chlorine dioxide gas. Background Art

[0002] Chlorine dioxide is a fourth-generation environmentally friendly disinfectant recommended by the World Health Organization, and is also rated as a disinfectant with a safety level of A1 (same safety level as sugar and salt) by the Food and Agriculture Organization of the United Nations. Chlorine dioxide has the functions of sterilization, bleaching, deodorization, disinfection, and preservation. The air contains a large number of bacteria that can cause disease. Chlorine dioxide preparations have strong sterilization ability and decompose quickly without residue. They are very suitable for indoor air spray sterilization and disinfection. In addition, spring and autumn are the seasons when infectious diseases such as colds and tracheitis are prevalent. Chlorine dioxide can be used to disinfect the environment, which can not only kill pathogenic microorganisms, but also eliminate odors and refresh the air. Therefore, chlorine dioxide is an ideal environmental disinfectant.

[0003] Chlorite and acid can quickly release a large number of chlorine dioxide molecules in a solution state, but the release rate is basically uncontrollable, the concentration is very high in a short period of time, and it can only be made and used immediately. At present, there are a variety of chlorine dioxide slow-release products on the market. Liquid slow-release agents can slowly produce chlorine dioxide by controlling the pH value of chlorite and acid solutions, but it is still difficult to accurately control the reaction process. Solid slow-release agents disperse chlorite and acid in organic or inorganic carriers. After the carrier absorbs moisture in the air, the reactants migrate and react in the carrier to slowly release chlorine dioxide, but the release rate is greatly affected by air humidity. Gel-type slow-release agents adsorb chlorine dioxide molecules into porous carriers or microcapsules and then slowly release them, but this adsorption and storage method is not stable enough, the moisture in the gel is easy to volatilize, and the release rate is fast at the beginning and slow in the later stage.

[0004] Therefore, it is urgent to develop a method for generating chlorine dioxide gas with a stable and controllable release rate to avoid a fast initial release rate and a slow release rate in the later stage. Summary of the invention

[0005] Based on the problems existing in the background technology, the present invention provides a method for generating chlorine dioxide gas.

[0006] The present invention is implemented by the following technical solutions:

[0007] A method for generating chlorine dioxide gas comprises mixing chlorine dioxide slow-release gel powder and water in a weight ratio of 1:(7-9), stirring the mixture into a gel state, and obtaining a chlorine dioxide slow-release gel, wherein chlorine dioxide gas is slowly and steadily released from the chlorine dioxide slow-release gel;

[0008] The chlorine dioxide slow-release gel powder comprises the following components in parts by weight: 20-40 parts of gel matrix, 1-10 parts of solid acid activator, 5-15 parts of chlorite, 1-5 parts of slow-release agent and 1-10 parts of hygroscopic salt.

[0009] Furthermore, the gel matrix is ​​a dried modified regenerated cellulose hydrogel.

[0010] Furthermore, the modified regenerated cellulose hydrogel is prepared by modifying the regenerated cellulose hydrogel with maleic anhydride, and the specific steps are: dissolving the regenerated cellulose in acetone, adding maleic anhydride, stirring and mixing evenly, heating to 50-60°C, adding a catalyst after the acetone is fully volatilized, continuing the reaction for 2-4 hours, and repeatedly washing with water after the reaction is completed to obtain the modified regenerated cellulose hydrogel.

[0011] Further, the source of the regenerated cellulose is selected from at least one of cotton linter pulp, bagasse pulp, palm leaf pulp, straw pulp, wood pulp or paper pulp;

[0012] The mass of the maleic anhydride is 10-15% of the mass of the regenerated cellulose;

[0013] The catalyst is triethylamine, and the amount of the catalyst used is 3-5% of the mass of the regenerated cellulose.

[0014] Furthermore, the solid acidic activator is one or more of citric acid, oxalic acid, tartaric acid, and L-malic acid.

[0015] Furthermore, the chlorite is one or more of potassium chlorite, sodium chlorite, magnesium chlorite, barium chlorite, and calcium chlorite.

[0016] Furthermore, the sustained-release agent is one or more of polyethylene glycol, polyvinyl alcohol, stearyl alcohol, and carbomer.

[0017] Furthermore, the hygroscopic salt is one or more of magnesium chloride, sodium chloride and calcium chloride.

[0018] Furthermore, the chlorine dioxide sustained-release gel powder is prepared by the following steps:

[0019] Step 1, removing water from the modified regenerated cellulose hydrogel, soaking it in an aqueous solution of a sustained-release agent, soaking for 0.5-1h, removing water from the mixed system, and obtaining a dry composite 1;

[0020] Step 2: Mix the solid acidic activator, chlorite and hygroscopic salt, add the dry composite 1 and continue mixing to obtain chlorine dioxide slow-release gel powder.

[0021] Furthermore, in step 1, removing the water in the modified regenerated cellulose hydrogel and removing the water in the mixed system are achieved by freeze drying.

[0022] Further, the time required for freeze drying the gel in step 1 is determined by the following method:

[0023]

[0024] in,

[0025] ρ is the density of the gel after freezing, in kg / m 3 ,

[0026] F is the latent heat of melting of gel, in J / kg,

[0027] β is the thermal conductivity of the dried layer, in m 2 / s,

[0028] η is the thermal conductivity of the dry layer, unit is W / (m·℃),

[0029] W is the temperature of the drying layer surface, unit is ℃,

[0030] N is the temperature of the sublimation interface, in °C,

[0031] r is the radius of the cylindrical gel, in m,

[0032] ε is the porosity coefficient of the freeze-dried material.

[0033] Beneficial effects of the present invention:

[0034] (1) The present invention uses regenerated cellulose hydrogel as a gel matrix. The regenerated cellulose hydrogel has a porous structure and a large number of hydroxyl groups on its molecular chain. After being modified with maleic anhydride, maleic anhydride and the hydroxyl groups on the regenerated cellulose molecular chain undergo an esterification reaction to introduce carboxyl groups. Due to the hydrogen bonding between the hydroxyl groups and the carboxyl groups, an interlaced network is constructed between the regenerated cellulose and the maleic anhydride, thereby improving the water retention of the regenerated cellulose hydrogel and increasing its water absorption and swelling properties in an acidic environment.

[0035] (2) The addition of a sustained-release agent can further construct the network structure of the regenerated cellulose hydrogel, allowing the generated chlorine dioxide gas to slowly dissipate into the air, thus avoiding a fast initial release rate and a slow release rate in the later stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to provide further explanation of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0037] Figure 1The chlorine dioxide release rate of the chlorine dioxide gas generation method of Examples 1-3 and Comparative Examples 1-3 varies with the use time. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0039] In the embodiment of the present invention, the regenerated cellulose is derived from cotton linter pulp, and is specifically prepared as follows:

[0040] 4.6 g of cotton linter pulp was dispersed in 100 mL of 7% NaOH / 12% urea aqueous solution, frozen at -20°C for 24 h, then dissolved by high-speed stirring, and degassed by centrifugation at 5000 r / min at 4°C for 15 min. The resulting solution was added dropwise to a 5% sulfuric acid coagulation bath and repeatedly washed with water to obtain spherical cellulose hydrogel.

[0041] Steps for modifying regenerated cellulose hydrogel:

[0042] Dissolve regenerated cellulose in acetone in a ratio of 20 g:50 mL. Add maleic anhydride in an amount of 10% of the mass of the regenerated cellulose. Stir and mix evenly. Heat to 60°C. After the acetone is fully evaporated, add triethylamine in an amount of 3% of the mass of the regenerated cellulose. Continue the reaction for 3 h. After the reaction is completed, wash repeatedly with water to obtain a modified regenerated cellulose hydrogel.

[0043] Example 1

[0044] The chlorine dioxide sustained-release gel powder comprises: 30 parts of gel matrix, 5 parts of citric acid, 10 parts of potassium chlorite, 3 parts of polyethylene glycol, and 5 parts of magnesium chloride.

[0045] Chlorine dioxide sustained-release gel powder is prepared by the following steps:

[0046] Step 1, freeze-drying the modified regenerated cellulose hydrogel to remove water, soaking it in an aqueous solution of polyethylene glycol, soaking it for 1 hour, and freeze-drying it to remove water in the mixed system to obtain a dry composite 1;

[0047] Step 2: Mix citric acid, potassium chlorite and magnesium chloride evenly, add dry composite 1 and continue mixing evenly to obtain chlorine dioxide sustained-release gel powder.

[0048] Chlorine dioxide gas generation method:

[0049] The chlorine dioxide slow-release gel powder is mixed with water in a weight ratio of 1:8 and stirred into a gel state to obtain the chlorine dioxide slow-release gel, from which chlorine dioxide gas is slowly and steadily released.

[0050] Example 2

[0051] The chlorine dioxide sustained-release gel powder comprises: 30 parts of gel matrix, 5 parts of citric acid, 10 parts of sodium chlorite, 3 parts of polyvinyl alcohol, and 5 parts of sodium chloride.

[0052] Chlorine dioxide sustained-release gel powder is prepared by the following steps:

[0053] Step 1, freeze-drying the modified regenerated cellulose hydrogel to remove moisture, soaking it in an aqueous solution of polyvinyl alcohol, soaking it for 0.5 hours, and freeze-drying it to remove water in the mixed system to obtain a dry composite 1;

[0054] Step 2: Mix citric acid, sodium chlorite and sodium chloride evenly, add dry composite 1 and continue mixing evenly to obtain chlorine dioxide sustained-release gel powder.

[0055] Chlorine dioxide gas generation method:

[0056] The chlorine dioxide slow-release gel powder is mixed with water in a weight ratio of 1:9 and stirred into a gel state to obtain the chlorine dioxide slow-release gel, from which chlorine dioxide gas is slowly and steadily released.

[0057] Example 3

[0058] The chlorine dioxide sustained-release gel powder comprises: 40 parts of gel matrix, 10 parts of L-malic acid, 15 parts of calcium chlorite, 5 parts of carbomer, and 10 parts of calcium chloride.

[0059] Chlorine dioxide sustained-release gel powder is prepared by the following steps:

[0060] Step 1, freeze-drying the modified regenerated cellulose hydrogel to remove moisture, soaking it in a carbomer aqueous solution, soaking it for 1 hour, and then freeze-drying it to remove water in the mixed system to obtain a dry composite 1;

[0061] Step 2: Evenly mix L-malic acid, calcium chlorite and calcium chloride, and add dry composite 1 and continue to mix evenly to obtain chlorine dioxide sustained-release gel powder.

[0062] Chlorine dioxide gas generation method:

[0063] The chlorine dioxide slow-release gel powder is mixed with water in a weight ratio of 1:9 and stirred into a gel state to obtain the chlorine dioxide slow-release gel, from which chlorine dioxide gas is slowly and steadily released.

[0064] Example 4

[0065] The time required for freeze drying the gel in step 1 during the preparation of the chlorine dioxide sustained-release gel powder is determined by the following method:

[0066]

[0067] in,

[0068] ρ is the density of the gel after freezing, in kg / m 3 ,

[0069] F is the latent heat of melting of gel, in J / kg,

[0070] β is the thermal conductivity of the dried layer, in m 2 / s,

[0071] η is the thermal conductivity of the dry layer, unit is W / (m·℃),

[0072] W is the temperature of the drying layer surface, unit is ℃,

[0073] N is the temperature of the sublimation interface, in °C,

[0074] r is the radius of the cylindrical gel, in m,

[0075] ε is the porosity coefficient of the freeze-dried material.

[0076] The beneficial effects of the above invention are as follows: a method for calculating the gel freezing time is determined, by which the time required for gel freezing can be directly calculated and determined, thereby shortening the effective time of the gel preparation system, avoiding unnecessary waste caused by too long freeze-drying time or incomplete gel cooling and substandard quality caused by too short freeze-drying time.

[0077] Comparative Example 1

[0078] In this comparative example, the gel matrix was dried agar.

[0079] The chlorine dioxide sustained-release gel powder comprises: 30 parts of gel matrix, 5 parts of citric acid, 10 parts of potassium chlorite, 3 parts of polyethylene glycol, and 5 parts of magnesium chloride.

[0080] Chlorine dioxide sustained-release gel powder is prepared by the following steps:

[0081] Step 1, soaking agar in an aqueous solution of polyethylene glycol for 1 hour, and then freeze-drying to remove water in the mixed system to obtain a dry composite 1;

[0082] Step 2: Mix citric acid, potassium chlorite and magnesium chloride evenly, add dry composite 1 and continue mixing evenly to obtain chlorine dioxide sustained-release gel powder.

[0083] Chlorine dioxide gas generation method:

[0084] The chlorine dioxide slow-release gel powder is mixed with water in a weight ratio of 1:8 and stirred into a gel state to obtain the chlorine dioxide slow-release gel, from which chlorine dioxide gas is slowly and steadily released.

[0085] Comparative Example 2

[0086] In this comparative example, the gel matrix is ​​a dry regenerated cellulose hydrogel without modification.

[0087] The chlorine dioxide sustained-release gel powder comprises: 30 parts of gel matrix, 5 parts of citric acid, 10 parts of potassium chlorite, 3 parts of polyethylene glycol, and 5 parts of magnesium chloride.

[0088] Chlorine dioxide sustained-release gel powder is prepared by the following steps:

[0089] Step 1, freeze-drying the modified regenerated cellulose hydrogel to remove water, soaking it in an aqueous solution of polyethylene glycol, soaking it for 1 hour, and freeze-drying it to remove water in the mixed system to obtain a dry composite 1;

[0090] Step 2: Mix citric acid, potassium chlorite and magnesium chloride evenly, add dry composite 1 and continue mixing evenly to obtain chlorine dioxide sustained-release gel powder.

[0091] Chlorine dioxide gas generation method:

[0092] The chlorine dioxide slow-release gel powder is mixed with water in a weight ratio of 1:8 and stirred into a gel state to obtain the chlorine dioxide slow-release gel, from which chlorine dioxide gas is slowly and steadily released.

[0093] Comparative Example 3

[0094] In this embodiment, the chlorine dioxide sustained-release gel powder comprises: 30 parts of gel matrix, 5 parts of citric acid, 10 parts of potassium chlorite, and 5 parts of magnesium chloride.

[0095] Chlorine dioxide sustained-release gel powder is prepared by the following steps:

[0096] Step 1, freeze-drying the modified regenerated cellulose hydrogel to remove moisture to obtain a dry composite 1;

[0097] Step 2: Mix citric acid, potassium chlorite and magnesium chloride evenly, add dry composite 1 and continue mixing evenly to obtain chlorine dioxide sustained-release gel powder.

[0098] Chlorine dioxide gas generation method:

[0099] The chlorine dioxide slow-release gel powder is mixed with water in a weight ratio of 1:8 and stirred into a gel state to obtain the chlorine dioxide slow-release gel, from which chlorine dioxide gas is slowly and steadily released.

[0100] Test example

[0101] Chlorine dioxide release test

[0102] The chlorine dioxide concentration and release time of the chlorine dioxide gas generation methods of Examples 1-3 and Comparative Examples 1-3 were tested, and the results are shown in Figure 1 middle.

[0103] Test method: 40 g of each sample was placed in a controlled release bottle (with a total release hole area of ​​1.2 cm 2 ) was placed in a 5L glass desiccator with an air inlet and an air outlet, and the air in the glass desiccator was collected with an air sampler at a flow rate of 200mL / min. The air was absorbed with pyronin solution, and the release rate of chlorine dioxide was calculated by fluorescence spectroscopy.

[0104] from Figure 1 As can be seen from the results, chlorine dioxide gas can be produced after mixing chlorine dioxide slow-release gel powder with water in Examples 1-3 and Comparative Examples 1-3, without an induction period. The chlorine dioxide release rate of Examples 1-3 is relatively stable, and the early release rate in Example 3 is higher than that in Examples 1 and 2, because the content of solid acidic activator and chlorite in the chlorine dioxide slow-release gel powder is relatively high, therefore, the solid acidic activator and chlorite content in the chlorine dioxide slow-release gel powder can be adjusted according to the release rate of actual needs. The gel matrix used in Comparative Example 1 is agar, and the chlorine dioxide release rate is relatively high in the first 3 days, and the chlorine dioxide release rate on the 4th day is significantly reduced, and it has been showing a downward trend, and chlorine dioxide cannot be stably released. The gel matrix used in Comparative Example 2 is unmodified regenerated cellulose, and the early chlorine dioxide release rate is also too fast, and the chlorine dioxide release rate slows down as the water in the gel evaporates in the later stage, and cannot be stably released. In Comparative Example 3, no slow-release agent is added, and the early release is also fast, and the later stage is slowly released, and the effect of stable release cannot be achieved.

[0105] Finally, it should be noted that the above-mentioned embodiments only express several implementation methods of the present invention and are not intended to limit the invention. For those skilled in the art, any modification, equivalent replacement, improvement, etc. made without departing from the concept of the present invention should be included in the protection scope of the invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for generating chlorine dioxide gas, characterized in that: The chlorine dioxide slow-release gel powder is mixed with water in a weight ratio of 1: (7-9), and stirred into a gel state to obtain a chlorine dioxide slow-release gel, from which chlorine dioxide gas is slowly and steadily released; The chlorine dioxide slow-release gel powder comprises the following components in parts by weight: 20-40 parts of gel matrix, 1-10 parts of solid acid activator, 5-15 parts of chlorite, 1-5 parts of slow-release agent, and 1-10 parts of hygroscopic salt; The gel matrix is ​​a dried modified regenerated cellulose hydrogel; The modified regenerated cellulose hydrogel is prepared by modifying the regenerated cellulose hydrogel with maleic anhydride, and the specific steps are: dissolving the regenerated cellulose in acetone, adding maleic anhydride, stirring and mixing evenly, heating to 50-60° C., adding a catalyst after the acetone is fully volatilized, continuing the reaction for 2-4 hours, and repeatedly washing with water after the reaction is completed to obtain the modified regenerated cellulose hydrogel; The mass of the maleic anhydride is 10-15% of the mass of the regenerated cellulose; The catalyst is triethylamine, and the amount of the catalyst is 3-5% of the mass of the regenerated cellulose.

2. The method for generating chlorine dioxide gas according to claim 1, characterized in that: The source of the regenerated cellulose is selected from at least one of cotton linter pulp, bagasse pulp, palm leaf pulp, straw pulp, wood pulp or paper pulp.

3. The method for generating chlorine dioxide gas according to claim 1, characterized in that: The solid acidic activator is one or more of citric acid, oxalic acid, tartaric acid and L-malic acid.

4. The method for generating chlorine dioxide gas according to claim 1, characterized in that: The chlorite is one or more of potassium chlorite, sodium chlorite, magnesium chlorite, barium chlorite and calcium chlorite.

5. The method for generating chlorine dioxide gas according to claim 1, characterized in that: The sustained-release agent is one or more of polyethylene glycol, polyvinyl alcohol, stearyl alcohol and carbomer.

6. The method for generating chlorine dioxide gas according to claim 1, characterized in that: The hygroscopic salt is one or more of magnesium chloride, sodium chloride and calcium chloride.

7. The method for generating chlorine dioxide gas according to claim 1, characterized in that: The chlorine dioxide slow-release gel powder is prepared by the following steps: Step 1, removing water from the modified regenerated cellulose hydrogel, soaking it in an aqueous solution of a sustained-release agent, soaking for 0.5-1h, removing water from the mixed system, and obtaining a dry composite 1; Step 2: Mix the solid acidic activator, chlorite and hygroscopic salt, add the dry composite 1 and continue mixing to obtain chlorine dioxide slow-release gel powder.

8. The method for generating chlorine dioxide gas according to claim 7, characterized in that: In step 1, removing the water in the modified regenerated cellulose hydrogel and removing the water in the mixed system are achieved by freeze drying.

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