A kind of formaldehyde removal color changing gel and preparation method thereof

Abstract

The present invention provides a formaldehyde removal color-changing gel and a preparation method thereof, wherein the formaldehyde removal color-changing gel comprises a component A paste and a component B activation liquid, and the preparation of the component A paste comprises the following raw materials by weight: 0.5-1 parts of chlorite, 10-20 parts of composite glue, 10-20 parts of polymer sustained-release agent, 5-10 parts of stabilizer, 5-10 parts of modified chitosan, 0.2-1 parts of color indicator, and 40-50 parts of deionized water; the preparation of the component B activation liquid comprises the following raw materials: 5-15 parts of organic acid and 85-95 parts of deionized water. The formaldehyde removal color-changing gel provided by the present invention has the characteristics of good antibacterial property, high temperature resistance and high formaldehyde removal rate, can be widely used in the field of environmental protection technology, and has good commercial application value.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, in particular to the technical field of formaldehyde removal, and in particular to a formaldehyde removal color-changing gel and a preparation method thereof. Background Art

[0002] Volatile organic compounds (VOCs) are one of the most common indoor environmental pollutants, and formaldehyde is a typical pollutant. When the human body is exposed to formaldehyde concentrations greater than 0.1 mg·m -3 When formaldehyde is in the environment, it may cause damage to the respiratory system, and long-term exposure will cause damage to other organs of the human body. Therefore, formaldehyde has been listed as a Class I carcinogen.

[0003] As people's living standards continue to improve, the forms and contents of interior decoration are gradually enriched. Artificial materials such as plywood, fiberboard, particleboard, and various paints and coatings in home decoration materials and furniture will release formaldehyde, causing the air pollution problem to become more serious and the harm to the human body is becoming more serious. Therefore, it is very important to develop formaldehyde removal materials that can be used to purify the air at home.

[0004] Chlorine dioxide is an excellent disinfectant and strong oxidant, and is widely used in water treatment, sterilization and disinfection, and other fields. Based on its good oxidation effect, chlorine dioxide can quickly oxidize and remove formaldehyde, and the method of removing formaldehyde by chlorine dioxide has the advantage of no secondary pollution of the formaldehyde removal product. However, chlorine dioxide has the disadvantage of being unstable, so it is often needed to be used in combination with gel-like substances to enhance its stability and sustained release; and the natural colloidal materials often used in gels have poor high temperature resistance, mechanical properties, and antibacterial properties, resulting in poor formaldehyde removal effect of formaldehyde removal gel.

[0005] Patent CN 114100343A discloses a sustained-release formaldehyde-removing gel with a color-indicating function. The sustained-release formaldehyde-removing gel prepared in the application is prepared from a main agent of chlorite, a sustained-release agent such as carrageenan, a stabilizer such as chloride, a redox indicator and a component A, and an activator such as a component B. It has low cost and good sustained-release properties, but the application does not solve the defects of insufficient high-temperature resistance, mechanical properties and antibacterial properties of natural colloids such as carrageenan, and the content of chlorite used in the application is too high, and the ideal effect cannot be achieved; Patent CN 117000025A discloses a formaldehyde-removing gel and a preparation method thereof. The formaldehyde-removing gel prepared in the application includes a gelling agent, a sodium chlorite solution, methylene blue powder, a yew extract and essence and other ingredients. It has the advantages of sustained-release chlorine dioxide release and continuous absorption of formaldehyde, but has the problems of poor antibacterial and mechanical properties, resulting in a relatively low formaldehyde removal effect.

[0006] Therefore, there is an urgent need on the market for a formaldehyde removal color-changing gel with high formaldehyde removal rate and stable release of chlorine dioxide. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention prepares and synthesizes a formaldehyde removal color-changing gel composed of a component A paste and a component B activation liquid. The component A paste uses chlorite as a precursor of chlorine dioxide and is prepared by adding components such as a polymer sustained-release agent and modified chitosan. The component B activation liquid uses an organic acid as a main component. When in use, the component B activation liquid is added dropwise to the component A paste, which has the advantages of a high formaldehyde removal rate and stable release of chlorine dioxide.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] On one hand, the present invention provides a formaldehyde removal color-changing gel. The preparation of the formaldehyde removal color-changing gel includes a paste of component A and an activation liquid of component B. The preparation of the paste of component A includes the following raw materials in parts by weight: 0.5-1 part of chlorite, 10-20 parts of composite adhesive, 10-20 parts of polymer sustained-release agent, 5-10 parts of stabilizer, 5-10 parts of modified chitosan, 0.2-1 part of color indicator, and 40-50 parts of deionized water; the preparation of the activation liquid of component B includes the following raw materials: 5-15 parts of organic acid and 85-95 parts of deionized water.

[0010] In some embodiments of the invention, the chlorite is sodium chlorite or potassium chlorite.

[0011] In some embodiments of the present invention, the composite gum is a mixture of carrageenan, locust bean gum and konjac gum.

[0012] Preferably, the mass ratio of the carrageenan, locust bean gum and konjac gum is 1:(0.3-0.5):(0.6-0.8).

[0013] More preferably, the mass ratio of the carrageenan, locust bean gum and konjac gum is 1:0.4:0.7.

[0014] In some embodiments of the present invention, the method for preparing the polymer sustained-release agent comprises the following steps:

[0015] (1) Mix starch and deionized water, heat to 75-85° C. and stir for 50-70 min under an inert atmosphere, add an initiator, N-isopropylacrylamide and nitric acid solution, stir for 3-5 h, add acetone, filter, dry, add an extracting solution for extraction, dry to obtain product 1 for later use;

[0016] (2) Take the product 1 of step (1), add deionized water, stir for 10-20 minutes, add aspartic acid, add sodium hydroxide solution to adjust the pH to 10-12, pass inert gas, heat to 65-75° C., stir for 9-11 hours, dialyze, and freeze-dry to obtain product 2 for use;

[0017] (3) Mix vanadium carbide and deionized water, sonicate for 70-74 hours, add tetramethylammonium hydroxide aqueous solution, stir for 22-26 hours, add product 2 of step (2), stir for 20-40 minutes, introduce inert gas, add ammonium persulfate, sonicate for 5-10 minutes, and stand at -5 to 0° C. for 23-25 ​​hours to obtain a polymer sustained-release agent.

[0018] In some embodiments of the present invention, in step (1), the mass ratio of starch, initiator and N-isopropylacrylamide is 1:(0.05-0.07):(1.6-2); in step (2), the mass ratio of product 1 and aspartic acid is 1:(1.6-2); in step (3), the mass ratio of product 2 and vanadium carbide is 1:(0.04-0.06).

[0019] Preferably, in step (1), the mass ratio of starch, initiator and N-isopropylacrylamide is 1:0.06:1.8; in step (2), the mass ratio of product 1 and aspartic acid is 1:1.8; in step (3), the mass ratio of product 2 and vanadium carbide is 1:0.05.

[0020] More preferably, the starch is corn amylopectin; and the initiator is cerium ammonium nitrate.

[0021] In the method of removing formaldehyde by chlorine dioxide, it is often necessary to add natural colloidal substances such as carrageenan as a sustained-release agent to ensure the stability of chlorite, the precursor of chlorine dioxide. However, natural colloidal substances have the disadvantages of poor high temperature resistance and low cross-linking degree, which have certain limitations on the sustained-release stability of chlorite.

[0022] The applicant uses a high molecular weight polyacrylamide with good adsorption performance, good high temperature resistance and mechanical properties as the base material of the polymer sustained-release agent, and modifies it to enhance its sustained-release effect on chlorite. On the one hand, the applicant selects amylopectin with high solubility, gelation and moisture retention to graft N-isopropylacrylamide under the action of the initiator ammonium cerium nitrate, and modifies the starch-grafted N-isopropylacrylamide with aspartic acid. The ammonium cerium nitrate forms a complex with starch through an oxidation-reduction reaction. 4+ Reduction to Ce 3+ , the hydrogen in the -OH in starch is oxidized to H +, starch forms free radicals, accompanied by the breaking of CC bonds, starch free radicals trigger the copolymerization of N-isopropylacrylamide, and the oxygen anions in aspartic acid and the carbon cations in acrylamide are cross-linked to form modified polyacrylamide (product 2), thereby improving the cross-linking and stability of the polymer sustained-release agent, thereby improving its sustained-release effect, and aspartic acid, as an amide amino acid, has a good absorption effect on formaldehyde, while improving the formaldehyde removal effect of the gel; on the other hand, the applicant uses vanadium carbide with high mechanical properties and corrosion resistance to modify the modified polyacrylamide, and the vanadium carbide is ultrasonically stripped in deionized water to obtain a nanosheet structure with rich hydroxyl groups and oxygen-containing functional groups on the surface, so that the vanadium carbide can be well cross-linked with the modified polyacrylamide, so that the polymer sustained-release agent has a micro-cross-linked network structure, thereby improving the mechanical properties, swelling properties and sustained-release properties of the polymer sustained-release agent; further, the hydroxyl groups on the surface of the vanadium carbide nanosheet layer and the carboxyl groups in aspartic acid are cross-linked, which can improve the stability of the polymer sustained-release agent.

[0023] In some embodiments of the present invention, the stabilizer is a mixture of 8-carboxyquinoline and hydrogen peroxide in a mass ratio of 1:(0.8-1.2).

[0024] Preferably, the stabilizer is a mixture of 8-carboxyquinoline and hydrogen peroxide in a mass ratio of 1:1.

[0025] In some embodiments of the present invention, the method for preparing the modified chitosan comprises the following steps:

[0026] 1) adding chitosan to an acetic acid aqueous solution and stirring to obtain solution 1 for later use; adding trans-4-(diethylamino)cinnamaldehyde to anhydrous ethanol and stirring to obtain solution 2 for later use; adding zinc chloride to dimethyltetrahydrofuran and stirring to obtain solution 3 for later use;

[0027] 2) adding solution 2 of step 1) dropwise into solution 1, heating, stirring, suction filtering, washing, and drying to obtain a solid for standby use;

[0028] 3) adding the solution 3 of step 1) dropwise to the solid of step 2), stirring, filtering, washing and drying to obtain modified chitosan.

[0029] In some embodiments of the present invention, in step 1), the mass ratio of chitosan, trans-4-(diethylamino)cinnamaldehyde and zinc chloride is 1:(0.5-0.7):(0.13-0.14).

[0030] Preferably, in step 1), the mass ratio of chitosan, trans-4-(diethylamino)cinnamaldehyde and zinc chloride is 1:0.6:0.135.

[0031] Chitosan has excellent adsorption properties due to its layered porous structure and has a good adsorption and removal effect on formaldehyde. Chitosan also has good water retention, which is beneficial to prolong the use time of formaldehyde removal gel. However, single chitosan has problems with poor mechanical properties and antibacterial properties.

[0032] The applicant selected trans-4-(diethylamino)cinnamaldehyde to modify chitosan. Trans-4-(diethylamino)cinnamaldehyde reacted with chitosan to form a Schiff base reaction. On the one hand, trans-4-(diethylamino)cinnamaldehyde had a strong inhibitory effect on bacterial motility and biofilm formation, which was beneficial to enhancing the antibacterial properties of chitosan. On the other hand, the ethyl side chain in trans-4-(diethylamino)cinnamaldehyde could make the modified chitosan have a polymer network structure, thereby enhancing the mechanical properties of chitosan. In addition, the amino group could cross-link with the hydroxyl group in chitosan, thereby enhancing the stability of chitosan and improving the adsorption of formaldehyde by chitosan. Furthermore, the applicant introduced Zn 2+ Chitosan is modified to further enhance its antibacterial properties, and the hydroxyl and amino groups in the chitosan structure will react with Zn 2+ The coordination effect makes the antibacterial property of chitosan more durable and improves the mechanical properties of chitosan, thereby improving the stable adsorption capacity of chitosan for formaldehyde. Furthermore, Zn 2+ It can also form coordination bonds with aspartic acid in the polymer sustained-release agent, which is beneficial to improving the stability of the formaldehyde removal gel, thereby improving the formaldehyde removal effect of the formaldehyde removal gel.

[0033] In some embodiments of the present invention, the organic acid is any one of citric acid, tartaric acid and oxalic acid.

[0034] In some embodiments of the invention, the color indicator is methylene blue.

[0035] The formaldehyde-removing color-changing gel prepared by the applicant is a paste of component A when not in use, which is a blue gel. When in use, the activation liquid of component B needs to be added dropwise to the paste of component A. The methylene blue is oxidized and faded by the released chlorine dioxide, which means that the formaldehyde-removing color-changing gel has started to remove formaldehyde, that is, the color indicator plays the role of indicating that the gel has started to remove formaldehyde.

[0036] Another aspect of the present invention further provides a method for preparing the formaldehyde removal color-changing gel described in the above technical solution, comprising the following steps:

[0037] S1. Preparation of paste of component A: mixing chlorite, composite adhesive, polymer sustained-release agent, stabilizer, modified chitosan, color indicator and deionized water, and stirring at 60-70° C. for 10-15 minutes to obtain paste of component A;

[0038] S2. Preparation of component B activation solution: Mix the organic acid and deionized water and stir for 5-10 minutes to obtain component B activation solution;

[0039] The paste of component A and the activating liquid of component B are packaged separately. When using, just add a drop of the activating liquid of component B into the paste of component A until it changes color.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The present invention prepares and synthesizes a formaldehyde removal color-changing gel composed of a component A paste and a component B activation liquid. The component A paste is prepared by using chlorite as a precursor of chlorine dioxide and adding a polymer sustained-release agent, modified chitosan and other ingredients. The component B activation liquid has an organic acid as a main component. Through the synergistic effect of the components, the formaldehyde removal color-changing gel has the characteristics of high formaldehyde removal rate and stable release of chlorine dioxide.

[0042] (2) The present invention selects polyacrylamide as the matrix material of the polymer sustained-release agent, uses starch to graft-modify the polyacrylamide under the action of the initiator ammonium cerium nitrate, and introduces aspartic acid and vanadium carbide to modify the polyacrylamide, so that the prepared polymer sustained-release agent has the characteristics of high cross-linking, high stability, and high sustained-release effect.

[0043] (3) The present invention uses chitosan, which has good adsorption capacity for formaldehyde, as a matrix, and introduces trans-4-(diethylamino)cinnamaldehyde and Zn 2+ Chitosan is modified to prepare modified chitosan, so that the antibacterial property and mechanical property of chitosan are improved, thereby improving the ability of chitosan to stably remove formaldehyde.

[0044] (4) The formaldehyde removal color-changing gel prepared by the present invention has a high formaldehyde removal rate and the chlorine dioxide in the gel can be stably released, having a good sustained-release effect, and can be widely used in the field of formaldehyde removal technology, with good commercial application value. DETAILED DESCRIPTION

[0045] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0046] In the following examples and comparative examples, except for the polymer sustained-release agent and modified chitosan, the other compound monomers and related reagents used can be purchased from the market. Among them, carrageenan and konjac gum were purchased from Jiangxi Fumeitai Biotechnology Co., Ltd.; locust bean gum was purchased from Shanghai Changcai Biotechnology Co., Ltd.; the starch was corn amylopectin, purchased from Shandong Kangnaxin Biotechnology Co., Ltd.; and chitosan was purchased from Shandong Weikan Biotechnology Co., Ltd.

[0047] Preparation Example 1

[0048] The synthesis method of polymer sustained-release agent A comprises the following steps:

[0049] (1) 10 g of corn amylopectin and 100 ml of deionized water were mixed, heated to 80° C. and stirred for 60 min under a N2 atmosphere, 0.6 g of cerium ammonium nitrate, 18 g of N-isopropylacrylamide and 6 ml of 1 mol / L nitric acid solution were added, stirred for 4 h, 40 ml of acetone was added, filtered, dried at 60° C. for 12 h, 100 ml of an extract (the extract was composed of 70 ml of anhydrous ethanol and 30 ml of deionized water) was added for extraction, and dried at 60° C. for 24 h to obtain product 1 for later use;

[0050] (2) Take 8 g of the product 1 of step (1), add 80 ml of deionized water, stir for 15 min, add 14.4 g of aspartic acid, add 0.1 mol / L sodium hydroxide solution to adjust the pH to 11, pass N2, heat to 70°C, stir for 10 h, dialyze with deionized water for 48 h, and freeze-dry at -40°C for 12 h to obtain product 2 for use;

[0051] (3) 0.1 g of vanadium carbide and 100 ml of deionized water were mixed, ultrasonicated for 72 h, 5 ml of 25 wt% tetramethylammonium hydroxide aqueous solution was added, stirred for 24 h, 2 g of the product 2 of step (2) was added, stirred for 30 min, N2 was introduced, 0.5 g of ammonium persulfate was added, ultrasonicated for 10 min, and allowed to stand at 0°C for 24 h to obtain a polymer sustained-release agent A.

[0052] Preparation Example 2

[0053] The specific implementation manner of polymer sustained-release agent B is the same as that of polymer sustained-release agent A, except that in step (1), the mass of the initiator is replaced with 0.4 g.

[0054] Preparation Example 3

[0055] The specific implementation manner of polymer sustained-release agent C is the same as that of polymer sustained-release agent A, except that in step (1), the mass of N-isopropylacrylamide is replaced with 15 g.

[0056] Preparation Example 4

[0057] The specific implementation manner of polymer sustained-release agent D is the same as that of polymer sustained-release agent A, except that in step (2), the mass of aspartic acid is replaced with 12 g.

[0058] Preparation Example 5

[0059] The specific implementation manner of polymer sustained-release agent E is the same as that of polymer sustained-release agent A, except that in step (3), the mass of vanadium carbide is replaced with 0.06 g.

[0060] Preparation Example 6

[0061] The synthetic method of modified chitosan A comprises the following steps:

[0062] 1) Add 10 g of chitosan to 100 ml of 1 wt% acetic acid aqueous solution and stir for 20 min to obtain solution 1 for later use; add 6 g of trans-4-(diethylamino)cinnamaldehyde to 30 ml of anhydrous ethanol and stir for 20 min to obtain solution 2 for later use; add 1.35 g of zinc chloride to 5 ml of dimethyltetrahydrofuran and stir for 15 min to obtain solution 3 for later use;

[0063] 2) adding solution 2 of step 1) dropwise into solution 1, heating to 50° C., stirring for 6 h, filtering with suction, washing with anhydrous ethanol twice, and drying at 60° C. for 12 h to obtain a solid for standby use;

[0064] 3) adding the solution 3 of step 1) dropwise to the solid of step 2), stirring for 20 min, filtering, washing the filter cake with deionized water for 3 times, and drying at 60° C. for 12 h to obtain modified chitosan A.

[0065] Preparation Example 7

[0066] The specific implementation manner of modified chitosan B is the same as that of modified chitosan A, except that in step 1), the mass of trans-4-(diethylamino)cinnamaldehyde is replaced with 4.5 g.

[0067] Preparation Example 8

[0068] The specific implementation manner of modified chitosan C is the same as that of modified chitosan A, except that in step 1), the mass of zinc chloride is replaced with 1 g.

[0069] Example 1

[0070] A formaldehyde removal color-changing gel is prepared by comprising a paste of component A and an activation liquid of component B. The paste of component A comprises the following raw materials by weight: 0.75 parts of sodium chlorite, 15 parts of a composite adhesive, 15 parts of a polymer sustained-release agent A, 7.5 parts of a stabilizer, 7.5 parts of a modified chitosan A, 0.6 parts of methylene blue, and 45 parts of deionized water; the activation liquid of component B comprises the following raw materials: 10 parts of citric acid and 90 parts of deionized water.

[0071] The composite glue is a mixture of carrageenan, locust bean gum and konjac gum in a mass ratio of 1:0.4:0.7.

[0072] The stabilizer is a mixture of 8-carboxyquinoline and hydrogen peroxide in a mass ratio of 1:1.

[0073] The preparation method of the formaldehyde removal color-changing gel in this embodiment comprises the following steps:

[0074] S1. Preparation of paste of component A: Sodium chlorite, composite adhesive, polymer sustained-release agent A, stabilizer, modified chitosan A, methylene blue and deionized water were mixed, and stirred at 65° C. for 13 min to obtain paste of component A;

[0075] S2. Preparation of component B activation solution: Mix citric acid and deionized water and stir for 8 minutes to obtain component B activation solution;

[0076] The paste of component A and the activating liquid of component B are packaged separately. When using, just add a drop of the activating liquid of component B into the paste of component A until it changes color.

[0077] Example 2

[0078] A formaldehyde removal color-changing gel is prepared by comprising a paste of component A and an activation liquid of component B. The paste of component A comprises the following raw materials by weight: 0.5 parts of potassium chlorite, 10 parts of composite adhesive, 15 parts of polymer sustained-release agent A, 5 parts of stabilizer, 5 parts of modified chitosan A, 0.2 parts of methylene blue and 40 parts of deionized water; the activation liquid of component B comprises the following raw materials: 5 parts of tartaric acid and 85 parts of deionized water.

[0079] The composite glue is a mixture of carrageenan, locust bean gum and konjac gum in a mass ratio of 1:0.3:0.6.

[0080] The stabilizer is a mixture of 8-carboxyquinoline and hydrogen peroxide, with a mass ratio of 1:0.8.

[0081] The preparation method of the formaldehyde removal color-changing gel in this embodiment comprises the following steps:

[0082] S1. Preparation of paste of component A: potassium chlorite, composite adhesive, polymer sustained-release agent A, stabilizer, modified chitosan A, methylene blue and deionized water are mixed, and stirred at 60° C. for 10 min to obtain paste of component A;

[0083] S2. Preparation of component B activation solution: tartaric acid and deionized water were mixed and stirred for 5 minutes to obtain component B activation solution;

[0084] The paste of component A and the activating liquid of component B are packaged separately. When using, just add a drop of the activating liquid of component B into the paste of component A until it changes color.

[0085] Example 3

[0086] A formaldehyde-removing color-changing gel is prepared by comprising a paste of component A and an activating liquid of component B. The paste of component A comprises the following raw materials by weight: 1 part of sodium chlorite, 20 parts of a composite adhesive, 15 parts of a polymer sustained-release agent A, 10 parts of a stabilizer, 10 parts of a modified chitosan A, 1 part of methylene blue, and 50 parts of deionized water; the activating liquid of component B comprises the following raw materials: 15 parts of oxalic acid and 95 parts of deionized water.

[0087] The composite glue is a mixture of carrageenan, locust bean gum and konjac gum in a mass ratio of 1:0.5:0.8.

[0088] The stabilizer is a mixture of 8-carboxyquinoline and hydrogen peroxide in a mass ratio of 1:1.2.

[0089] The preparation method of the formaldehyde removal color-changing gel in this embodiment comprises the following steps:

[0090] S1. Preparation of paste of component A: Sodium chlorite, composite adhesive, polymer sustained-release agent A, stabilizer, modified chitosan A, methylene blue and deionized water are mixed, and stirred at 70° C. for 15 min to obtain paste of component A;

[0091] S2. Preparation of component B activation solution: Mix oxalic acid and deionized water and stir for 10 minutes to obtain component B activation solution;

[0092] The paste of component A and the activating liquid of component B are packaged separately. When using, just add a drop of the activating liquid of component B into the paste of component A until it changes color.

[0093] Example 4

[0094] A formaldehyde removal color-changing gel is prepared by comprising a paste of component A and an activation liquid of component B. The paste of component A comprises the following raw materials by weight: 0.6 parts of sodium chlorite, 12 parts of a composite adhesive, 10 parts of a polymer sustained-release agent A, 6 parts of a stabilizer, 7.5 parts of a modified chitosan A, 0.4 parts of methylene blue, and 43 parts of deionized water; the activation liquid of component B comprises the following raw materials: 7 parts of citric acid and 87 parts of deionized water.

[0095] The composite adhesive and stabilizer are the same as those in Example 1.

[0096] The preparation method of the formaldehyde removal color-changing gel in this embodiment is the same as that in Example 1.

[0097] Example 5

[0098] A formaldehyde-removing color-changing gel is prepared by comprising a paste of component A and an activating liquid of component B. The paste of component A comprises the following raw materials by weight: 0.8 parts of sodium chlorite, 18 parts of a composite adhesive, 20 parts of a polymer sustained-release agent A, 8 parts of a stabilizer, 7.5 parts of a modified chitosan A, 0.8 parts of methylene blue, and 48 parts of deionized water; the activating liquid of component B comprises the following raw materials: 12 parts of citric acid and 92 parts of deionized water.

[0099] The composite adhesive and stabilizer are the same as those in Example 1.

[0100] The preparation method of the formaldehyde removal color-changing gel in this embodiment is the same as that in Example 1.

[0101] Example 6

[0102] This embodiment provides a formaldehyde removal color-changing gel and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the polymer sustained-release agent B replaces the polymer sustained-release agent A in equal amounts.

[0103] Example 7

[0104] This embodiment provides a formaldehyde removal color-changing gel and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the polymer sustained-release agent A is replaced by an equal amount of polymer sustained-release agent C.

[0105] Example 8

[0106] This embodiment provides a formaldehyde removal color-changing gel and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the polymer sustained-release agent A is replaced by an equal amount of polymer sustained-release agent D.

[0107] Example 9

[0108] This embodiment provides a formaldehyde removal color-changing gel and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the polymer sustained-release agent E replaces the polymer sustained-release agent A in equal amounts.

[0109] Example 10

[0110] This embodiment provides a formaldehyde removal color-changing gel and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified chitosan A is replaced by modified chitosan B in equal amounts.

[0111] Embodiment 11

[0112] This embodiment provides a formaldehyde removal color-changing gel and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified chitosan A is replaced by modified chitosan C in equal amounts.

[0113] Example 12

[0114] This embodiment provides a formaldehyde removal color-changing gel and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that polyacrylamide is used instead of polymer sustained-release agent A.

[0115] Polyacrylamide was purchased from Huzhou Zeyuan Environmental Protection Technology Co., Ltd.

[0116] Comparative Example 1

[0117] This comparative example provides a formaldehyde removal color-changing gel and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that chitosan is used instead of modified chitosan A.

[0118] Performance Testing

[0119] The formaldehyde removal rates of the formaldehyde removal color-changing gels of Examples 1-12 and Comparative Example 1 were tested, and the test results are shown in Table 1.

[0120] 100 g of component A in the formaldehyde removal color-changing gel in the above examples and comparative examples were respectively placed in a sealed container, the lid was opened, and the component B activation liquid was added dropwise to the component A paste. After the component A paste changed color, the components were placed in a 10 m 3 The initial concentration was 1 mg / m 3 The formaldehyde removal rate was tested in a formaldehyde-enclosed chamber after 24 hours.

[0121] Formaldehyde removal rate (%) = (initial formaldehyde concentration - formaldehyde concentration at 24h) / initial formaldehyde concentration × 100%

[0122] The formaldehyde detection method shall be in accordance with the method specified in GB / T18204.26-2000.

[0123] Table 1

[0124] Group Formaldehyde removal rate (%) Example 1 98.4 Example 2 98.2 Example 3 98.1 Example 4 97.9 Example 5 97.5 Example 6 94.0 Example 7 94.5 Example 8 94.3 Example 9 94.2 Example 10 93.5 Embodiment 11 93.3 Example 12 90.5 Comparative Example 1 89.5

[0125] It can be seen from the data in Table 1 that the formaldehyde removal color-changing gel in Examples 1-5 of the present invention has a relatively high formaldehyde removal rate as a whole. Among them, Examples 6-9 respectively changed the ratio of the added initiator, acrylamide monomer, aspartic acid and vanadium carbide in the polymer sustained-release agent, so that the high temperature resistance, stability, cross-linking and sustained-release effect of the polymer sustained-release agent decreased, thereby resulting in a decrease in the formaldehyde removal rate of the formaldehyde removal color-changing gel; Examples 10-11 respectively changed the ratio of trans-4-(diethylamino)cinnamaldehyde and Zn 2+ The modification ratio of chitosan leads to a decrease in the antibacterial and mechanical properties of chitosan, which affects the chitosan's adsorption capacity for formaldehyde, and further shows a decrease in the formaldehyde removal rate of the formaldehyde removal color-changing gel; Example 12 and Comparative Example 1 respectively use polyacrylamide and chitosan to replace the polymer sustained-release agent A and modified chitosan A, and tests show that the formaldehyde removal rates of the formaldehyde removal color-changing gel both show poor results.

[0126] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A formaldehyde removal color changing gel, characterized in that: The formaldehyde removal color-changing gel comprises a paste of component A and an activation liquid of component B. The preparation of the paste of component A comprises the following raw materials by weight: 0.5-1 part of chlorite, 10-20 parts of composite adhesive, 10-20 parts of polymer sustained-release agent, 5-10 parts of stabilizer, 5-10 parts of modified chitosan, 0.2-1 part of color indicator, and 40-50 parts of deionized water; the preparation of the activation liquid of component B comprises the following raw materials: 5-15 parts of organic acid and 85-95 parts of deionized water; The chlorite is sodium chlorite or potassium chlorite; The composite glue is a mixture of carrageenan, locust bean gum and konjac gum; The preparation method of the polymer sustained-release agent comprises the following steps: (1) Mix starch and deionized water, heat to 75-85°C under an inert atmosphere, and stir for 50-70 min. Add initiator, N-isopropylacrylamide and nitric acid solution, stir for 3-5 h, add acetone, filter, dry, add extractant to extract, and dry to obtain product 1 for later use. (2) Take the product 1 of step (1), add deionized water, stir for 10-20 minutes, add aspartic acid, add sodium hydroxide solution to adjust the pH to 10-12, pass inert gas, heat to 65-75°C, stir for 9-11 hours, dialyze, and freeze-dry to obtain product 2 for use; (3) Mix vanadium carbide and deionized water, sonicate for 70-74 hours, add tetramethylammonium hydroxide aqueous solution, stir for 22-26 hours, add product 2 of step (2), stir for 20-40 minutes, introduce inert gas, add ammonium persulfate, sonicate for 5-10 minutes, and stand at -5~0°C for 23-25 ​​hours to obtain a polymer sustained-release agent; In the step (1), the mass ratio of starch, initiator and N-isopropylacrylamide is 1:(0.05-0.07):(1.6-2); in the step (2), the mass ratio of product 1 and aspartic acid is 1:(1.6-2); in the step (3), the mass ratio of product 2 and vanadium carbide is 1:(0.04-0.06); The stabilizer is a mixture of 8-carboxyquinoline and hydrogen peroxide; The preparation method of the modified chitosan comprises the following steps: 1) Add chitosan to an acetic acid aqueous solution and stir to obtain solution 1 for later use; add trans-4-(diethylamino)cinnamaldehyde to anhydrous ethanol and stir to obtain solution 2 for later use; add zinc chloride to dimethyltetrahydrofuran and stir to obtain solution 3 for later use; 2) adding solution 2 of step 1) dropwise into solution 1, heating, stirring, suction filtering, washing, and drying to obtain a solid for standby use; 3) adding the solution 3 of step 1) dropwise to the solid of step 2), stirring, filtering, washing and drying to obtain modified chitosan; In the step 1), the mass ratio of chitosan, trans-4-(diethylamino)cinnamaldehyde and zinc chloride is 1:(0.5-0.7):(0.13-0.14).

2. The formaldehyde removal color changing gel according to claim 1, characterized in that: The stabilizer is a mixture of 8-carboxyquinoline and hydrogen peroxide, with a mass ratio of 1:(0.8-1.2).

3. The formaldehyde removal color changing gel according to claim 1, characterized in that: The organic acid is any one of citric acid, tartaric acid and oxalic acid.

4. A method for preparing the formaldehyde removal color-changing gel according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Preparation of paste of component A: mixing chlorite, composite adhesive, polymer sustained-release agent, stabilizer, modified chitosan, color indicator and deionized water, and stirring at 60-70° C. for 10-15 minutes to obtain paste of component A; S2. Preparation of component B activation solution: Mix the organic acid and deionized water, and stir for 5-10 minutes to obtain component B activation solution; The paste of component A and the activating liquid of component B are packaged separately. When using, just add a drop of the activating liquid of component B into the paste of component A until it changes color.