A kind of highly efficient formaldehyde removal color-changing granules and preparation method thereof

Abstract

The present invention provides a highly efficient formaldehyde removal color-changing particle and a preparation method thereof. The preparation of the formaldehyde removal color-changing particle includes the following raw materials by weight: 50-70 parts of modified activated carbon, 15-25 parts of metal oxide catalyst, 10-20 parts of natural mineral composite particles, 3-7 parts of potassium permanganate, 1-4 parts of dispersant, and 50-60 parts of deionized water. The formaldehyde removal color-changing particle provided by the present invention has high adsorption and high decomposition performance for formaldehyde, 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, specifically to the technical field of formaldehyde removal, and particularly to a kind of highly efficient formaldehyde removal color-changing particles and a preparation method thereof. Background Art

[0002] Formaldehyde is a colorless gas with a pungent odor. It has a strong irritating effect on the eyes and nose, and has varying degrees of damage to the respiratory tract, digestive system, circulatory system, and mental system. In recent years, researchers have developed many materials that can reduce or even eliminate formaldehyde from the dual perspectives of adsorption and decomposition.

[0003] At present, from the perspective of formaldehyde adsorption, the raw materials of activated carbon are easy to obtain, low in cost, and have large specific surface area and loose porous structure characteristics, which have good effects in formaldehyde adsorption. Although activated carbon has good formaldehyde removal characteristics, it still has some defects. For example, activated carbon has the problem of easy adsorption saturation, resulting in insufficient adsorption performance; and activated carbon itself is easy to absorb moisture and has no antibacterial properties, so it is easy to mold and acidify after long-term storage. From the perspective of formaldehyde decomposition, it mainly refers to the use of catalysts to degrade formaldehyde into harmless carbon dioxide and water, but there are problems such as expensive catalysts or low catalytic activity.

[0004] Patent CN 106111059A discloses an activated carbon-based formaldehyde removal material. The formaldehyde removal material prepared in this application includes raw materials such as attapulgite, activated carbon, titanium dioxide and activated alumina powder. It has the advantages of low cost and high formaldehyde removal efficiency, but does not solve the problems of low adsorption efficiency and easy moisture absorption of activated carbon; Patent CN 104383810A discloses a material for rapid decomposition and absorption of formaldehyde in the air. The material prepared in this application is prepared from activated carbon, mixed crystal nano-titanium dioxide, alumina and other materials, and has multiple functions such as moisture absorption and sterilization, but does not mention the problem of low adsorption activity of activated carbon.

[0005] Therefore, there is an urgent need on the market for a highly efficient formaldehyde-removing color-changing particle with high adsorption and high catalytic decomposition properties. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention selects modified activated carbon as the main adsorbent of formaldehyde and a metal oxide catalyst as the decomposition catalyst of formaldehyde, and then adds natural mineral composite particles, potassium permanganate and a dispersant to prepare a highly efficient formaldehyde-removing color-changing particle, which has the advantages of high adsorption and high catalytic decomposition of formaldehyde.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] On the one hand, the present invention provides a high-efficiency formaldehyde-removing color-changing particles. The preparation of the formaldehyde-removing color-changing particles includes the following raw materials, calculated by weight: 50-70 parts of modified activated carbon, 5-10 parts of metal oxide catalyst, 10-20 parts of natural mineral composite particles, 3-7 parts of potassium permanganate, 1-4 parts of dispersant, and 50-60 parts of deionized water.

[0009] In some embodiments of the present invention, the method for preparing the modified activated carbon comprises the following steps:

[0010] (1) washing, drying, crushing and sieving the pomelo peel raw material to obtain pomelo peel powder for later use;

[0011] (2) taking the pomelo peel powder of step (1), adding a zinc chloride aqueous solution and deionized water, stirring, impregnating, drying, calcining, adding a hydrochloric acid solution, impregnating, washing, drying, sieving, and obtaining pomelo peel-based activated carbon for later use;

[0012] (3) taking the grapefruit peel-based activated carbon of step (2), adding ammonium polyphosphate and anhydrous ethanol, stirring, ultrasonicating, impregnating, high temperature activating, washing, and drying to obtain a solid for use;

[0013] (4) Take the solid of step (3), add nitric acid solution, heat, stir, wash, dry, add N,N-dicyclohexylcarbodiimide and benzoylhydrazide, stir, heat to 70-90°C for reaction for 5-7h, filter, wash, and dry to obtain modified activated carbon.

[0014] In some embodiments of the present invention, in step (3), the mass ratio of grapefruit peel-based activated carbon to ammonium polyphosphate is 1:(4-6).

[0015] Preferably, in step (3), the mass ratio of grapefruit peel-based activated carbon to ammonium polyphosphate is 1:5.

[0016] In some embodiments of the present invention, in step (4), the mass ratio of solid, N,N-dicyclohexylcarbodiimide and benzoyl hydrazide is 1:(0.1-0.3):(0.5-0.6).

[0017] Preferably, in step (4), the mass ratio of solid, N,N-dicyclohexylcarbodiimide and benzohydrazide is 1:0.2:0.55.

[0018] From the perspective of formaldehyde adsorption, activated carbon has become the most commonly used material for formaldehyde adsorption due to its low cost, large specific surface area and high loose structure. However, activated carbon as a whole still has problems such as low adsorption activity, easy adsorption saturation, and susceptibility to moisture and mold.

[0019] The applicant selected natural, environmentally friendly and low-cost pomelo peel as the raw material for preparing activated carbon, and prepared pomelo peel-based activated carbon by zinc chloride activation method. By controlling the ratio of zinc chloride activator and pomelo peel powder, the pomelo peel-based activated carbon has the characteristics of high specific surface area and high pore volume. In addition, there are functional groups such as hydroxyl, carboxyl, amine and pyrone on the surface of the pomelo peel-based activated carbon, which makes the pomelo peel-based activated carbon have high adsorption activity, and intramolecular hydrogen bonds are formed between hydroxyl and ketone groups, which is beneficial to improve the stability of activated carbon. Furthermore, the applicant introduced N atoms into the pomelo peel-based activated carbon by using ammonium polyphosphate. Internally, the difference in the radii of N and C atoms is used to increase the pore size and specific surface area of ​​the modified activated carbon, and since N atoms are hydrophobic, N-doped activated carbon can effectively prevent the activated carbon from getting moldy after being placed for a long time; further, the applicant uses N,N-dicyclohexylcarbodiimide as a shrinking agent for amination reaction, introduces benzohydrazide, and grafts benzohydrazide onto the activated carbon structure, so that the modified activated carbon structure contains a polyamine structure, so that the activated carbon not only has formaldehyde adsorption properties but also can achieve the effect of removing formaldehyde through the reaction between amine groups and formaldehyde, thereby improving the formaldehyde removal effect of the activated carbon.

[0020] In some embodiments of the present invention, the method for preparing the metal oxide catalyst comprises the following steps:

[0021] 1) Add cobalt nitrate, manganese nitrate and citric acid into deionized water, stir at 45-55°C for 1.5-2.5h, add ammonium tungstate and deionized water, stir for 50-70min, filter and dry to obtain the product for later use;

[0022] 2) Take aluminum oxide, add deionized water, stir for 30-40 minutes, add the product of step 1), dropwise add sodium hydroxide solution, adjust pH to 9.5-10.5, stir for 2-4 hours, centrifuge, wash, dry, and calcine to obtain a metal oxide catalyst.

[0023] In some embodiments of the present invention, in step 1), the mass ratio of manganese nitrate, cobalt nitrate and ammonium tungstate is 1:(0.6-0.7):(0.4-0.6).

[0024] Preferably, in step 1), the mass ratio of manganese nitrate, cobalt nitrate and ammonium tungstate is 1:0.63:0.5.

[0025] In some embodiments of the present invention, in step 2), the mass ratio of alumina to product is 1:(0.2-0.4).

[0026] Preferably, in step 2), the mass ratio of alumina to product is 1:0.3.

[0027] The catalytic decomposition technology of formaldehyde refers to the conversion of formaldehyde into harmless carbon dioxide and water, which has the advantages of high efficiency, low cost and no toxic by-products. Among various catalysts, manganese dioxide is widely used in the research of catalytic decomposition of formaldehyde at room temperature due to its unique crystal structure, high catalytic performance, low price and certain antibacterial properties. However, the active sites on the surface of manganese dioxide are inevitably covered by water molecules, which inhibits the generation of active oxygen, resulting in reduced catalytic activity and stability of manganese dioxide.

[0028] In order to improve the catalytic activity and stability of manganese dioxide as a formaldehyde removal catalyst, on the one hand, the applicant prepared cobalt-manganese oxide by citric acid complexation, and by controlling the ratio of cobalt and manganese, manganese was allowed to enter the lattice of cobalt oxide. The abundant high-valent manganese and high-valent cobalt on the catalyst surface promoted the formation of catalyst defects, thereby increasing the number of oxygen vacancies, which was beneficial to the exposure of active sites and promoted the absorption of formaldehyde; further, the applicant introduced transition metal tungsten into cobalt-manganese oxide by ammonium tungstate. The metal tungsten can be evenly distributed in the cobalt-manganese oxide due to its small particle size, and the activation energy of manganese dioxide catalyzing the decomposition of formaldehyde is reduced after tungsten modification, thereby improving the cobalt-manganese oxide. The catalytic activity and stability are improved, and the introduction of tungsten also improves the antibacterial properties of the catalyst; further, cobalt and tungsten act as a binder, which improves the stability and corrosion resistance of the catalyst, and the cross-linking effect occurs between the citrate and the ammonium in ammonium tungstate, which is also beneficial to the improvement of the stability of the catalyst; on the other hand, the applicant uses alumina as a carrier to load tungsten-cobalt-manganese composite oxides, and utilizes the large specific surface area and pore size of alumina to overcome the disadvantage of reduced stability of manganese dioxide at room temperature due to the adsorption of water vapor, and there are a large number of hydroxyl groups on the surface of alumina, which is beneficial to the adsorption of low-concentration formaldehyde and intermediates, thereby improving the catalytic oxidation performance of the catalyst.

[0029] In some embodiments of the present invention, the natural mineral composite particles are a combination of at least two of attapulgite, sepiolite and diatomaceous earth.

[0030] In some embodiments of the present invention, the dispersant is sodium bentonite or lithium bentonite.

[0031] Another aspect of the present invention further provides a method for preparing the highly efficient formaldehyde-removing color-changing particles described in the above technical solution, comprising the following steps:

[0032] S1. Add potassium permanganate into deionized water and stir for 20-40 minutes to obtain a potassium permanganate aqueous solution for standby use;

[0033] S2. Add modified activated carbon, metal oxide catalyst and natural mineral composite particles into the potassium permanganate aqueous solution of step S1, stir for 10-20 min, add dispersant, stir for 20-40 min, filter, dry at 50-70°C for 12 h, sieve and granulate to obtain high-efficiency formaldehyde-removing and color-changing particles.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention selects modified activated carbon as the main adsorbent of formaldehyde and a metal oxide catalyst as the decomposition catalyst of formaldehyde, and then adds natural mineral composite particles, potassium permanganate and a dispersant to prepare a highly efficient formaldehyde-removing color-changing particle. Through the synergistic effect of the various components, the formaldehyde-removing color-changing particle has the dual formaldehyde-removing characteristics of high adsorption and high catalytic decomposition.

[0036] (2) The present invention selects activated carbon as the matrix material for adsorbing formaldehyde, and performs N-doping and benzoylhydrazide modification on the activated carbon. The N-doping increases the pore size and specific surface area of ​​the activated carbon, improves the formaldehyde removal efficiency of the activated carbon, and improves the hydrophobicity of the activated carbon to prevent the occurrence of mold on the activated carbon. Benzoylhydrazide introduces amino groups into the activated carbon structure, so that the activated carbon can react with formaldehyde at the same time, thereby increasing the formaldehyde removal efficiency of the activated carbon.

[0037] (3) The present invention uses manganese dioxide as the main component of the formaldehyde removal catalyst, modifies it with cobalt nitrate and ammonium tungstate, synthesizes tungsten-cobalt-manganese composite oxide, and uses aluminum oxide as a carrier to improve the catalytic activity and antibacterial property of the catalyst.

[0038] (4) The formaldehyde-removing color-changing particles prepared by the present invention have high adsorption and catalytic decomposition properties for formaldehyde, can be widely used in the field of formaldehyde removal technology, and have good commercial application value. DETAILED DESCRIPTION

[0039] 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.

[0040] In the following embodiments and comparative examples, except for modified activated carbon and metal oxide catalyst, the other compound monomers and related reagents used can be purchased from the market. Among them, ammonium polyphosphate was purchased from Dongguan Hongtaiji Flame Retardant Material Co., Ltd.; attapulgite was purchased from Shijiazhuang Zezhang Mining Co., Ltd.; sepiolite was purchased from Shijiazhuang Shuangfu Technology Co., Ltd.; diatomite was purchased from Shengzhou Huali Diatomite Products Co., Ltd.; sodium-based bentonite was purchased from Shijiazhuang Yunshi New Building Materials Co., Ltd.; lithium-based bentonite was purchased from Xinyang Pingqiao District Yanxu Insulation Materials Factory.

[0041] Preparation Example 1

[0042] The synthesis method of modified activated carbon A comprises the following steps:

[0043] (1) 20 g of pomelo peel raw material was washed three times with deionized water, dried at 110° C. for 4 h, crushed, and passed through a 30-mesh sieve to obtain pomelo peel powder for later use;

[0044] (2) Take 10 g of the pomelo peel powder of step (1), add 30 ml of a 15 wt % zinc chloride aqueous solution and 100 ml of deionized water, stir for 15 min, soak for 12 h, dry at 110° C. for 4 h, calcine at 600° C. for 2 h, add 30 ml of a 10 wt % hydrochloric acid solution, soak for 2 h, wash with deionized water until pH = 7, dry at 85° C. for 4 h, and pass through a 60-mesh sieve to obtain pomelo peel-based activated carbon for later use;

[0045] (3) Take 4 g of the grapefruit peel-based activated carbon prepared in step (2), add 20 g of ammonium polyphosphate and 100 ml of anhydrous ethanol, stir for 30 min, ultrasonicate for 30 min, soak for 2 h, activate at 300 ° C for 3 h, wash with deionized water 3 times, and dry at 100 ° C for 4 h to obtain a solid for standby use;

[0046] (4) Take 10 g of the solid obtained in step (3), add 100 ml of 36 wt% nitric acid solution, heat to 80°C, stir for 6 h, wash with deionized water until pH = 7, dry at 100°C for 4 h, add 2 g of N,N-dicyclohexylcarbodiimide and 5.5 g of benzohydrazide, stir for 5 min, heat to 80°C to react for 6 h, filter, wash with deionized water 3 times, and dry at 90°C for 4 h to obtain modified activated carbon A.

[0047] Preparation Example 2

[0048] The specific implementation method of modified activated carbon B is the same as that of modified activated carbon A, except that in step (3), the mass of ammonium polyphosphate is replaced with 14 g.

[0049] Preparation Example 3

[0050] The specific implementation method of modified activated carbon C is the same as that of modified activated carbon A, except that in step (4), the mass of N,N-dicyclohexylcarbodiimide is replaced with 0.9 g.

[0051] Preparation Example 4

[0052] Modified activated carbon D, the specific implementation method is the same as modified activated carbon A, except that: in step (4), the mass of benzoyl hydrazide is replaced by 4.5 g.

[0053] Preparation Example 5

[0054] The synthesis method of the metal oxide catalyst A comprises the following steps:

[0055] 1) Add 3.6 g of cobalt nitrate, 5.7 g of manganese nitrate and 8.4 g of citric acid to 50 ml of deionized water, stir at 50 ° C for 2 h, add 2.85 g of ammonium tungstate and 30 ml of deionized water, stir for 60 min, filter, and dry at 60 ° C for 12 h to obtain the product for use;

[0056] 2) Take 8 g of alumina, add 50 ml of deionized water, stir for 35 min, add 2.4 g of the product, add dropwise 0.2 mol / L of sodium hydroxide solution, adjust the pH to 10, stir for 3 h, centrifuge, wash 3 times each with anhydrous ethanol and deionized water, dry at 80 ° C for 12 h, and calcine at 200 ° C for 4 h to obtain metal oxide catalyst A.

[0057] Preparation Example 6

[0058] The specific implementation manner of metal oxide catalyst B is the same as that of metal oxide catalyst A, except that in step 1), the mass of cobalt nitrate is replaced with 3 g.

[0059] Preparation Example 7

[0060] The specific implementation manner of metal oxide catalyst C is the same as that of metal oxide catalyst A, except that in step 1), the mass of ammonium tungstate is replaced with 2.1 g.

[0061] Preparation Example 8

[0062] The specific implementation manner of metal oxide catalyst D is the same as that of metal oxide catalyst A, except that in step 2), the mass of aluminum oxide is replaced with 5 g.

[0063] Example 1

[0064] The invention discloses a highly efficient formaldehyde-removing color-changing particle. The preparation of the formaldehyde-removing color-changing particle includes the following raw materials, measured by weight: 60 parts of modified activated carbon A, 7.5 parts of metal oxide catalyst A, 15 parts of natural mineral composite particles, 5 parts of potassium permanganate, 2.5 parts of sodium bentonite, and 55 parts of deionized water.

[0065] The natural mineral composite particles are a mixture of attapulgite, sepiolite and diatomaceous earth, with a mass ratio of 1:0.5:1.

[0066] The preparation method of the highly efficient formaldehyde-removing color-changing particles in this embodiment comprises the following steps:

[0067] S1. Add potassium permanganate into deionized water and stir for 30 min to obtain a potassium permanganate aqueous solution for use;

[0068] S2. Add modified activated carbon A, metal oxide catalyst A and natural mineral composite particles to the potassium permanganate aqueous solution of step S1, stir for 15 minutes, add sodium bentonite, stir for 30 minutes, filter with suction, dry at 60°C for 12 hours, pass through a 100-mesh sieve, and granulate to a particle size of 3 mm to obtain high-efficiency formaldehyde-removing and color-changing particles.

[0069] Example 2

[0070] The invention discloses a highly efficient formaldehyde-removing color-changing particle. The preparation of the formaldehyde-removing color-changing particle includes the following raw materials, measured by weight: 60 parts of modified activated carbon A, 5 parts of metal oxide catalyst A, 10 parts of natural mineral composite particles, 3 parts of potassium permanganate, 1 part of lithium-based bentonite, and 50 parts of deionized water.

[0071] The natural mineral composite particles are a mixture of attapulgite and diatomaceous earth with a mass ratio of 1:1.

[0072] The preparation method of the highly efficient formaldehyde-removing color-changing particles in this embodiment comprises the following steps:

[0073] S1. Add potassium permanganate into deionized water and stir for 20 min to obtain a potassium permanganate aqueous solution for use;

[0074] S2. Add modified activated carbon A, metal oxide catalyst A and natural mineral composite particles to the potassium permanganate aqueous solution of step S1, stir for 10 min, add lithium bentonite, stir for 20 min, filter, dry at 50°C for 12 h, pass through a 100-mesh sieve, and granulate to a particle size of 3 mm to obtain high-efficiency formaldehyde-removing and color-changing particles.

[0075] Example 3

[0076] The invention discloses a highly efficient formaldehyde-removing color-changing particle. The preparation of the formaldehyde-removing color-changing particle includes the following raw materials, measured by weight: 60 parts of modified activated carbon A, 10 parts of metal oxide catalyst A, 20 parts of natural mineral composite particles, 7 parts of potassium permanganate, 4 parts of sodium bentonite, and 60 parts of deionized water.

[0077] The natural mineral composite particles are a mixture of sepiolite and diatomaceous earth with a mass ratio of 1:1.

[0078] The preparation method of the highly efficient formaldehyde-removing color-changing particles in this embodiment comprises the following steps:

[0079] S1. Add potassium permanganate into deionized water and stir for 40 min to obtain a potassium permanganate aqueous solution for standby use;

[0080] S2. Add modified activated carbon A, metal oxide catalyst A and natural mineral composite particles to the potassium permanganate aqueous solution of step S1, stir for 20 minutes, add sodium bentonite, stir for 40 minutes, filter, dry at 70°C for 12 hours, pass through a 100-mesh sieve, and granulate to a particle size of 3 mm to obtain high-efficiency formaldehyde-removing and color-changing particles.

[0081] Example 4

[0082] The invention discloses a highly efficient formaldehyde-removing color-changing particle. The preparation of the formaldehyde-removing color-changing particle includes the following raw materials, measured by weight: 50 parts of modified activated carbon A, 7.5 parts of metal oxide catalyst A, 12 parts of natural mineral composite particles, 4 parts of potassium permanganate, 2 parts of sodium bentonite, and 52 parts of deionized water.

[0083] The natural mineral composite particles are the same as those in Example 1.

[0084] The preparation method of the highly efficient formaldehyde-removing color-changing particles in this embodiment is the same as that in Example 1.

[0085] Example 5

[0086] The invention discloses a highly efficient formaldehyde-removing color-changing particle. The preparation of the formaldehyde-removing color-changing particle includes the following raw materials, measured by weight: 70 parts of modified activated carbon A, 7.5 parts of metal oxide catalyst A, 17 parts of natural mineral composite particles, 6 parts of potassium permanganate, 3 parts of sodium bentonite, and 57 parts of deionized water.

[0087] The natural mineral composite particles are the same as those in Example 1.

[0088] The preparation method of the highly efficient formaldehyde-removing color-changing particles in this embodiment is the same as that in Example 1.

[0089] Example 6

[0090] This embodiment provides a highly efficient formaldehyde-removing color-changing particle and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified activated carbon A is replaced by modified activated carbon B in equal amounts.

[0091] Example 7

[0092] This embodiment provides a highly efficient formaldehyde-removing color-changing particle and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified activated carbon A is replaced by modified activated carbon C in equal amounts.

[0093] Example 8

[0094] This embodiment provides a highly efficient formaldehyde-removing color-changing particle and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified activated carbon A is replaced by modified activated carbon D in equal amounts.

[0095] Example 9

[0096] This embodiment provides a highly efficient formaldehyde-removing color-changing particle and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the metal oxide catalyst A is replaced by an equal amount of metal oxide catalyst B.

[0097] Example 10

[0098] This embodiment provides a highly efficient formaldehyde-removing color-changing particle and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the metal oxide catalyst A is replaced by an equal amount of metal oxide catalyst C.

[0099] Embodiment 11

[0100] This embodiment provides a highly efficient formaldehyde-removing color-changing particle and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the metal oxide catalyst A is replaced by an equal amount of metal oxide catalyst D.

[0101] Example 12

[0102] This embodiment provides a highly efficient formaldehyde-removing color-changing particle and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that an equal amount of manganese dioxide is used to replace the metal oxide catalyst A.

[0103] Comparative Example 1

[0104] This comparative example provides a highly efficient formaldehyde-removing color-changing particle and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that an equal amount of grapefruit peel-based activated carbon is used to replace the modified activated carbon A, and the grapefruit peel-based activated carbon is obtained by step (2) of Preparation Example 1.

[0105] Performance Testing

[0106] The formaldehyde removal effects of the formaldehyde-removing color-changing particles of the above-mentioned Examples 1-12 and Comparative Example 1 were tested, and the test results are shown in Table 1.

[0107] 100 g of the formaldehyde-removing color-changing particles in the above examples and comparative examples were respectively poured into mesh bags and 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.

[0108] Formaldehyde removal rate (%) = (initial formaldehyde concentration - formaldehyde concentration at 24h) / initial formaldehyde concentration × 100%

[0109] The formaldehyde detection method shall be in accordance with the method specified in GB / T18204.26-2000.

[0110] Table 1

[0111]

[0112]

[0113] It can be seen from the data in Table 1 that the formaldehyde removal color-changing particles in Examples 1-5 of the present invention have a relatively high formaldehyde removal rate, i.e., formaldehyde removal effect. Among them, Examples 6-8 respectively changed the proportion of N doping and the proportion of amine grafting in the modified activated carbon, so that the pore size and specific surface area of ​​the activated carbon were reduced, the hydrophobicity was reduced, and the reaction activity with formaldehyde was reduced, thereby resulting in a decrease in the formaldehyde removal effect of the modified activated carbon, and then a decrease in the formaldehyde removal rate of the formaldehyde removal color-changing particles; Examples 9-11 respectively changed the proportion of tungsten-cobalt-manganese composite oxide synthesis and the ratio between tungsten-cobalt-manganese composite oxide and alumina carrier, resulting in a decrease in the catalytic oxidation activity of the metal oxide catalyst to formaldehyde, and then a decrease in the formaldehyde removal rate of the formaldehyde removal color-changing particles; Example 12 and Comparative Example 1 respectively selected manganese dioxide and activated carbon to replace the metal oxide catalyst A and the modified activated carbon A, and the test found that the formaldehyde removal effect of the formaldehyde removal color-changing particles showed poor results.

[0114] 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 highly efficient formaldehyde removal color-changing particle, characterized in that: The following raw materials are used to prepare the formaldehyde-removing and color-changing particles: 50-70 parts of modified activated carbon, 5-10 parts of metal oxide catalyst, 10-20 parts of natural mineral composite particles, 3-7 parts of potassium permanganate, 1-4 parts of dispersant, and 50-60 parts of deionized water. The preparation method of the modified activated carbon comprises the following steps: (1) washing, drying, crushing and sieving the pomelo peel raw material to obtain pomelo peel powder for later use; (2) taking the pomelo peel powder of step (1), adding a zinc chloride aqueous solution and deionized water, stirring, impregnating, drying, calcining, adding a hydrochloric acid solution, impregnating, washing, drying, sieving, and obtaining pomelo peel-based activated carbon for later use; (3) Take the grapefruit peel-based activated carbon of step (2), add ammonium polyphosphate and anhydrous ethanol, stir, ultrasonicate, immerse, activate at high temperature, wash, and dry to obtain a solid for use; (4) Take the solid obtained in step (3), add nitric acid solution, heat, stir, wash, dry, add N,N-dicyclohexylcarbodiimide and benzoylhydrazide, stir, heat to 70-90°C for reaction for 5-7h, filter, wash, and dry to obtain modified activated carbon; In the step (3), the mass ratio of grapefruit peel-based activated carbon to ammonium polyphosphate is 1:(4-6); In the step (4), the mass ratio of the solid, N,N-dicyclohexylcarbodiimide and benzoylhydrazide is 1:(0.1-0.3):(0.5-0.6); The preparation method of the metal oxide catalyst comprises the following steps: 1) Add cobalt nitrate, manganese nitrate and citric acid into deionized water, stir at 45-55°C for 1.5-2.5h, add ammonium tungstate and deionized water, stir for 50-70min, filter and dry to obtain the product for later use; 2) Take alumina, add deionized water, stir for 30-40 minutes, add the product of step 1), dropwise add sodium hydroxide solution, adjust pH to 9.5-10.5, stir for 2-4 hours, centrifuge, wash, dry, and calcine to obtain a metal oxide catalyst; In the step 1), the mass ratio of manganese nitrate, cobalt nitrate and ammonium tungstate is 1: (0.6-0.7): (0.4-0.6); In the step 2), the mass ratio of alumina to product is 1:(0.2-0.4).

2. The highly efficient formaldehyde-removing color-changing particles according to claim 1, characterized in that: The natural mineral composite particles are a combination of at least two of attapulgite, sepiolite and diatomaceous earth.

3. The highly efficient formaldehyde-removing color-changing particles according to claim 1, characterized in that: The dispersant is sodium bentonite or lithium bentonite.

4. A method for preparing the highly efficient formaldehyde-removing color-changing particles according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Add potassium permanganate into deionized water and stir for 20-40 minutes to obtain a potassium permanganate aqueous solution for standby use; S2. Add modified activated carbon, metal oxide catalyst and natural mineral composite particles into the potassium permanganate aqueous solution of step S1, stir for 10-20 min, add dispersant, stir for 20-40 min, filter, dry at 50-70°C for 12 h, sieve and granulate to obtain high-efficiency formaldehyde-removing and color-changing particles.

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