WO2022253117A1 - Functional material for visual degradation of formaldehyde and vocs at room temperature and atmospheric pressure and preparation method therefor - Google Patents

Abstract

A functional material for the visual degradation of formaldehyde and VOCs at room temperature and atmospheric pressure, comprising a loading agent, an oxidant, a catalyst, a reinforcing agent, and a ligand. By means of the synergistic strengthening effect of the loading agent, the oxidant, the catalyst, the reinforcing agent and the ligand, the material has the effect of degrading formaldehyde and VOCs at room temperature and atmospheric pressure, and the structure and color of the material itself change before and after a reaction with formaldehyde and VOCs. The speed and extent of the reaction may be directly observed with the naked eye and indicated.

Description

Functional material and preparation method for visually degrading formaldehyde and VOCs at normal temperature and pressure technical field

The invention belongs to the field of new materials and gas pollution control, and specifically relates to a functional material and a preparation method for visually degrading formaldehyde and VOCs at normal temperature and pressure, which are used in the fields of gas purification, environmental protection, and general health.

Background technique

With the continuous development of the economy and the rapid development of real estate, automobile, chemical, pharmaceutical, textile and other industries, people's requirements for housing, travel, clothing, medical care, living environment, etc. are constantly increasing. However, the existing production methods of material materials are accompanied by a large amount of polluting gas emissions. On the one hand, various decoration materials in the interior, car, and space, such as formaldehyde and VOCs (volatile organic compounds); on the other hand, a large number of industrial enterprises emit tons of VOCs gas into the atmosphere. These have seriously damaged people's health and living environment. The above problems have become the social issues that people are most concerned about.

Formaldehyde is a colorless, highly irritating gas and a highly toxic substance. The lot of documents record, formaldehyde mainly shows aspects such as allotriosmia, stimulation, allergy, pulmonary function, liver function and immunologic dysfunction to health effects. The low-concentration formaldehyde solution is the formalin that the hospital soaks the corpse specimens to prevent decay. High indoor concentration of formaldehyde and VOC may cause various diseases such as leukemia and cancer.

VOC (Volatile Organic Compounds) is often overlooked by people, but it may be a more important indoor pollutant in the car. Taking benzene as an example, benzene in the ambient atmosphere mostly invades the body through the respiratory tract in the form of vapor. Animal experiments have found that long-term exposure to benzene will lead to the decline of hematopoietic stem cell function and the occurrence of various diseases, such as aplastic anemia and myelodysplastic syndrome syndrome, leukemia, etc.; the acute poisoning of benzene is due to the short-term work of the contactor in the environment of extremely high concentration of benzene vapor, which mainly paralyzes the central nervous system; long-term repeated exposure to low-concentration benzene can cause chronic poisoning, mainly manifested in the Harm to nervous system and hematopoietic system. Benzene is a human carcinogen confirmed by the WHO, and it is also the most harmful substance to human health among the eight substances determined by the standard. Benzene is the most strictly controlled harmful substance among the pollutants in the car. WHO's recommendation for benzene in ambient air is that the lower the better.

Formaldehyde and VOCs exist in various decoration materials indoors and in cars, including wood boards, wood-based panels, paints, coatings, leather, curtains, glues, wallpapers, and textiles. The release time of formaldehyde and VOCs is very long, generally within 10-15 years, during this period, formaldehyde will continue to be released from the above items. People spend more than 80-90% of their time indoors or in cars, so the air quality indoors and in cars will directly affect people's health. The problem of air pollution in indoor cars is encountered by almost everyone in their lifetime. Therefore, the development of efficient formaldehyde and VOCs purification technology is very important to the health of individuals and the whole society.

The existing methods for removing formaldehyde in indoor cars mainly include adsorption, photocatalysis, biological method, ozone method, chlorine dioxide method, plant purification method, catalytic oxidation method, etc. The adsorption method is to use the adsorption properties of porous substances, such as activated carbon, molecular sieve, silica gel, zeolite and other materials to absorb formaldehyde in the air. This method is only physical adsorption, and does not really remove formaldehyde in the space. After heating or violent shaking, Formaldehyde will be released a second time and is not persistent. The adsorption method is not a targeted adsorption, and will also adsorb other gases such as water vapor and carbon dioxide, and the adsorption efficiency of formaldehyde is low. Photocatalysis requires ultraviolet light, which will age various decoration materials. It is not easy to use indoors and in cars, and the nano-scale solid particles used may cause secondary pollution. Biological methods are inconvenient and inefficient due to the limited biological activity conditions of bacteria and microorganisms. Both the ozone method and the chlorine dioxide method will produce strong irritant, so they are not suitable for use indoors and in cars. Plants have little effect on the purification of formaldehyde and VOCs indoors and in cars.

In a chemical reaction, some of the original chemical bonds of the reacting molecules must dissociate and form new chemical bonds before the reaction can occur, which requires a certain amount of activation energy. In the catalytic oxidation reaction, the catalyst has chemical adsorption on the reactant molecules, which activates the reactant molecules, reduces the activation energy of the reaction, and accelerates the reaction rate. In some systems where chemical reactions are difficult to occur, the addition of catalysts helps to rearrange the chemical bonds of reacting molecules, thus accelerating chemical reactions. Catalytic oxidation method to remove formaldehyde is to convert formaldehyde into carbon dioxide and water through catalytic oxidation, which is not limited by ultraviolet rays or biological conditions, and has no disadvantage of adsorption saturation by adsorption method. At present, the catalysts for removing formaldehyde are mainly systems supporting noble metals such as Pt, Pd, Ag, and Au, and transition metal oxide catalysts. Noble metal catalysts cannot be widely used due to the high cost of noble metals and their susceptibility to temperature and pollution. Chinese patent CN10380574 discloses a catalyst for catalyzing the oxidation of formaldehyde at room temperature. The catalyst component is 0.2-30%, preferably 1-10%, according to the metal loading, which is too expensive and difficult to popularize. Chinese patent CN1698932A uses Au as a noble metal to catalyze the oxidation of formaldehyde, but only at a relatively high temperature (80-100° C.) can it exert better catalytic efficiency, which limits its wide application. U.S. Patent US 5585083 catalyzes formaldehyde containing 12wt% Pt, which can completely oxidize formaldehyde at 25°C, but the cost of precious metals is too high, which limits its application field. Chinese patent CN1795970A discloses a catalyst for the complete catalytic oxidation of low-concentration formaldehyde at room temperature. The catalyst is based on the oxidation of non-noble metals, such as cerium dioxide, zirconium dioxide, titanium dioxide, aluminum oxide, and lanthanum oxide. But the catalyst still needs to add a small amount of precious metals, such as gold, silver, platinum, rhodium. Chinese patent CN102941111A shows a metal carrier-supported catalyst for room temperature formaldehyde purification. The catalyst is composed of a metal carrier, a porous inorganic material loaded on the metal carrier, and a noble metal element, an alkali metal or an alkaline earth metal compound. Hopcalate catalysts are catalysts composed of various metal oxides, which can be used for low-temperature and room-temperature catalytic oxidation of carbon monoxide, but poor moisture resistance is its fatal shortcoming, and it will be inactivated after moisture absorption. In short, most of the catalysts in the existing formaldehyde catalytic oxidation technology contain noble metals, which lead to high prices, high use constraints, and are not easy to be widely used on a large scale. However, those formaldehyde catalysts that do not require noble metal elements have disadvantages such as low reaction efficiency, high activation temperature, poor moisture resistance, and instability.

In addition, the common disadvantage of the above-mentioned catalysts is the lack of signal indicators that directly indicate the progress and severity of the catalysis or reaction. Ordinary users and professionals can only know the usage of the catalyst through professional instruments and complex tests and analysis. Ordinary users cannot intuitively perceive the use effect of the catalyst, cannot intuitively judge the wear and tear of the catalyst in real time, cannot intuitively know the pollution degree of formaldehyde and VOC in the room, car, and space, and when the catalyst needs to be replaced. The above-mentioned catalysts have many problems from the perspective of customer experience. Chinese patent CN1660477A discloses a composite material composed of a porous carrier and potassium permanganate. This material utilizes the oxidizing properties of potassium permanganate to treat harmful gases in the air. Phenomena to judge whether the material fails. However, since potassium permanganate itself is a strong oxidizing substance, it is easy to damage the surface of furniture or clothing in contact with it when used alone. In addition, the color change range of this material is from red to brown, and the color change is not sensitive. Chinese patent CN 102527228 A discloses a visually discolored formaldehyde scavenger, which is composed of three components: an adsorption component, a catalytic component and a discoloration component, although it can discolor after contacting formaldehyde, etc. The discoloration is dependent on the effect of the acid-base indicator, rather than the discoloration caused by the failure of the active functional components in the true sense, and cannot directly indicate the change in the purification ability of the material.

Furthermore, most of the existing technologies have only studied the catalytic oxidation effect of catalysts on formaldehyde, but in fact, in indoor and car interior spaces, benzene and its homologues are more serious health hazards. On the other hand, since benzene and its homologues are also important components that cause indoor and car odors, those catalysts or reactions that can only catalyze the oxidation of formaldehyde cannot really reduce indoor, car, and space odors.

Contents of the invention

Aiming at the defects and deficiencies of the prior art, the purpose of the present invention is to provide a functional material that efficiently catalyzes the oxidation of formaldehyde and VOCs at normal temperature and pressure, which can reduce costs without using precious metals, and is conducive to popularization and application. The principle is that when formaldehyde and VOCs are in contact with the surface of the functional material, a special oxidation system is used to catalyze the oxidation of formaldehyde and VOCs in the space at normal temperature and pressure, and oxidize large molecular organic pollutants into small molecular organic compounds until Oxidation into _CO2 and water, thereby reducing the concentration of organic gas pollutants in the space.

The functional material of the present invention does not need to work under conditions of high physical and chemical energy such as light, ozone, strong acid, strong alkali, high temperature, high pressure, etc., and can directly visually indicate the removal of formaldehyde and VOCs through the significant change in color before and after the material itself reacts The speed and intensity of the reaction. When the material absorbs formaldehyde and VOCs, the material itself reacts, the internal structure of the material changes reversely before and after the reaction, electronic transitions occur, and the absorption spectrum of the material changes, resulting in a color change.

Taking the reaction chemical equation between the active ingredient of one of the materials and formaldehyde as an example, the principle of catalytic oxidation and discoloration of the material to remove formaldehyde and VOCs is illustrated. The reaction equation is:

Among them, ferrate catalyzes oxidation reaction with formaldehyde under acidic conditions, and the +6 valent iron in ferrate (its electron configuration is 1s ² 2s 2 ^{2p 6} 3s ² 3p ⁶ 3d ² ) is reduced to +3 in ferric hydroxide Valence iron (the electronic configuration is 1s ² 2s ² 2p ⁶ 3s ² 3p ⁶ 3d ⁵ ), the final products are iron hydroxide, carbon dioxide and water. Among them, the reactant ferrate ion is purple-black, and the product ferric hydroxide is reddish-brown, and the color changes obviously before and after the reaction. This is because the ferrate is a tetrahedral configuration, after the reaction, the structure changes and thus the color changes. Among them, the enhancer enhances the interfacial reaction so as to strengthen the reaction effect.

The functional material can not only be made into a solid state, but also into a liquid state, which essentially solves the problems of performance attenuation and structural damage after the solid catalyst absorbs moisture, making the application field and use scene very wide. In addition, this functional material is self-absorbing and does not require a power device. Its principle is based on Fick's first law, using the gas concentration diffusion principle to allow high-concentration formaldehyde and VOCs in the space to diffuse to the material and react, thereby obtaining The effect of automatic absorption. This material not only has excellent low-temperature activity and removal efficiency for formaldehyde catalytic oxidation, but also has excellent low-temperature activity, removal efficiency, and broad-spectrum effectiveness for various VOCs, and can truly remove odors in rooms, cars, and spaces. At the same time, it has high stability and water resistance, and is suitable for gas purification in indoor, vehicle, office buildings, school buildings, hospitals, shopping malls, closed or semi-closed spaces, industrial VOC treatment and other fields. In order to achieve the above object, the present invention adopts the following technical solutions:

A functional material for visually degrading formaldehyde and VOCs at normal temperature and pressure, the functional material including a load agent, an oxidant, a catalyst, a reinforcing agent and a ligand;

The loading agent is one or more of inorganic carriers;

The oxidizing agent is an oxidizing substance with a standard hydrogen electrode potential greater than zero;

The catalyst is a catalytically active element, inorganic compound or organic compound of a non-noble transition metal;

The enhancer is one or more of potassium aluminum sulfate, sodium tartrate, calcium phosphate or sodium pyrophosphate;

The ligands are atoms, molecules or ions that can bond with metal atoms.

Each part of the functional material interacts synergistically to degrade formaldehyde and VOCs at normal temperature and pressure, and the color change indicates the reaction process and reaction intensity.

Preferably, the loading agent includes but not limited to activated carbon, white carbon black, calcium carbonate, asbestos, diatomaceous earth, kaolin, perlite, barium sulfate, titanium dioxide, talcum powder, gypsum, mica, graphite, zeolite, magnesium sulfate or one or more of clay.

Preferably, the specific surface area of the loading agent is 1-2000m ² /g, for example, 10m ² /g, 100m ² /g, 200m ² /g, 400m ² /g, 600m ² /g, 800m ² /g can be selected , 1000m ² /g, 1200m ² /g, 1500m ² /g, preferably 10-100m ² /g, more preferably 10-50m ² /g. The particle diameter is 500-3000nm, for example, 500nm, 1000nm, 1500nm, 2000nm, 2500nm, 3000nm, preferably 650-1500nm, more preferably 800-1000nm.

Preferably, based on 100% of the mass of the functional material, the loading agent accounts for 20-80% by mass of the functional material, preferably 30-80%, and the specific surface area, particle size, and ratio of the loading agent can ensure On the premise that the functional material has excellent catalytic activity, the stability, moisture resistance and manufacturing elasticity of the material are remarkably improved.

Preferably, the oxidizing agent includes, but is not limited to, copper divalent, cobalt trivalent, nickel tetravalent, manganese tetravalent, permanganate MnO ₄ ^- , dichromate Cr ₂ O ₇ ^2- , ferrate FeO ₄ ^{2 -} , the compound of tetravalent lead or one or a combination of sulfuric acid _H2SO4 , nitric acid _HNO3 , bromine _Br2 , perchloric _{acid HClO4} , hypochlorous acid HClO or hydrogen peroxide _{H2O2 ;} More preferably, the oxidizing agent includes but not limited to permanganate MnO ₄ ^- , dichromate Cr ₂ O ₇ ^2- , ferrate FeO ₄ ^2- , tetravalent lead compounds or sulfuric acid H ₂ SO ₄ , nitrate HNO _3. One or a combination of bromine Br ₂ , perchloric acid HClO ₄ , hypochlorous acid HClO or hydrogen peroxide H ₂ O ₂ .

Preferably, based on 100% of the mass of the functional material, the mass percentage of the oxidizing agent is 0.1-25%.

Preferably, the catalyst includes but is not limited to one or a combination of oxides or salts thereof of vanadium, cobalt, iron, chromium, manganese, nickel, molybdenum, lanthanum, cadmium, copper or zinc, the The salt is an inorganic salt, preferably nitrate, sulfate or chloride salt, more preferably ferric sulfate, ferric chloride, ferrous chloride, ferrous sulfate, manganese nitrate, nickel sulfate, copper sulfate, zinc nitrate, molybdenum nitrate, Cobalt nitrate, cobalt sulfate, lanthanum nitrate, chromium nitrate, etc., based on 100% of the mass of the functional material, the mass percentage of the catalyst is 0.1-30%.

Preferably, based on 100% of the mass of the functional material, the mass fraction percentage of the reinforcing agent is 0.1-10%.

Preferably, the ligands include but are not limited to water, chloride ions, borate ions, phosphate ions or oxalate ions in salts or solutions; When ions, phosphate ions or oxalate ions are used as ligands, the corresponding cations are sodium ions or potassium ions; based on 100% mass of the functional material, the mass fraction percentage of the ligands is 1-20%.

According to different processes and requirements, the functional material of the present invention can be made into solid state and liquid state. The functional materials can be used directly without further assembly into modules.

The present invention also provides a preparation method of the functional material, comprising the steps of:

(1) Adding an enhancer and a ligand to a solution containing an oxidizing agent and a catalyst, and adjusting the pH and temperature so that the solution just precipitates out to obtain a loading liquid;

(2) dispersing the loading agent in the loading liquid, and slowly forming a precipitate by adjusting the pH to obtain a solid-liquid mixture;

(3) After the solid-liquid mixture is left to age, the solid is separated to obtain the obtained product.

Further, the preparation method also includes the following steps:

(4) dissolving the solid obtained in step (3) in a solvent to obtain a liquid material; the solvent is one or more of water, ethanol-water solution, hypochlorous acid, sulfuric acid, and hydrochloric acid.

Preferably, the mass ratio of ethanol and water in the ethanol-water solution described in step (4) is 1:7, the concentration of hypochlorous acid is 0.01～0.5mol/L, the concentration of sulfuric acid is 0.1～1mol/L, the concentration of hydrochloric acid 0.05~3mol/L.

For liquid materials, 100% of the above mass fraction is the total mass of solid materials.

Preferably, the loading agent is pre-treated by calcination.

Preferably, the calcination temperature is 700-1200° C.; the calcination time is 12-24 hours.

Preferably, the solvent of the solution described in step (1) includes but not limited to 10wt% hydrochloric acid ethanol solution, 5wt% sulfuric acid ethanol solution or 25wt% hydrochloric acid aqueous solution or a mixture of several.

Preferably, the method for adjusting pH in the step (1) is to add one or more of sodium hydroxide solution, ammonia solution, sodium carbonate solution or sodium bicarbonate solution.

Preferably, the concentration of the sodium hydroxide solution is 0.1 to 2 mol/L, the concentration of the ammonia solution is 0.2 to 2 mol/L, the concentration of the sodium carbonate solution is 0.1 to 1 mol/L, and the concentration of the sodium bicarbonate solution is 0.05 to 1.5 mol /L.

In step (1), the pH and temperature are adjusted to allow precipitation, and the temperature range is generally controlled to be 35-95°C.

Preferably, the method for adjusting pH in step (2) is adding one or more of citric acid, hydrochloric acid or acetic acid. Preferably, the concentration of citric acid is 0.1-3 mol/L, the concentration of hydrochloric acid is 0.1-0.5 mol/L, and the concentration of acetic acid is 0.1-2 mol/L.

Preferably, in step (3), aging for 24-48 hours.

Preferably, step (3) further includes the steps of washing, drying, and activating the obtained solid. Preferably, the drying temperature is 40-130° C., and the drying time is 6-12 hours. Preferably, the firing activation condition is: firing at 800-1500° C. for 10-24 hours under an inert atmosphere to activate.

The application of the above-mentioned functional materials in absorbing and/or degrading formaldehyde and/or VOCs is also within the protection scope of the present invention.

The specific application method is to absorb and/or degrade formaldehyde and/or VOCs under normal temperature and pressure. When the color of the functional material is completely changed to another color, or the shape of the functional material is completely changed, it indicates that the functional material is completely deactivated, and a new functional material needs to be replaced to absorb and/or degrade formaldehyde and/or VOCs. For example, the color change can change from black to yellowish brown, from purple to black, or from purple to khaki, from green to yellow, from brown to yellow, from blue to black, etc.; changes in shape Refers to the transition between liquid state, gel state, and solid state, for example, it can change from solid state to liquid state, or from liquid state to gel state, or from liquid state to solid state, etc.

A gas purification product contains the functional material of the invention. The purpose of the air purification is mainly to remove formaldehyde and/or VOCs in the gas, and the product can be made of the functional materials of the present invention into various blocks, wires, flakes or granules The material itself, the product can also be a product formed by a combination of the functional material and other materials, and the product can also be loaded with the functional material of the present invention in the device or inside, and contact with air as much as possible to achieve For the purpose of removing formaldehyde and/or VOCs in the air, the product application scenarios include but not limited to industrial, commercial, household, and automotive use.

The catalytic oxidation of formaldehyde and VOCs is due to the polarization and protonation of oxidants and catalysts. The pore structure of the carrier and the electric field distribution of the active atoms of the oxidants and catalysts distributed on it determine the path of gas adsorption, activation and reaction. Therefore, in the narrow micropore structure of the support agent, subtle changes in the electric field distribution of active atoms and changes in pH will significantly affect the catalytic performance.

In the present invention, through the addition of enhancers and ligands, multi-site catalysis is constructed in the micropore structure of the carrier, that is, a single reactant molecule such as formaldehyde and VOCs will be affected by multiple active sites in the pores of the carrier. adsorption. When a single molecule is captured and adsorbed by an active center, it will be additionally adsorbed by the adjacent active center, resulting in a significant change in the adsorption entropy, and a change in the transition state structure of the molecular activation, thereby changing the reaction path and causing the active center to go up. The actual reaction activation energy of the reaction to generate intermediate cracking products is lower and the transition state is more stable, which greatly improves the reaction efficiency, making the material capable of degrading formaldehyde and VOCs at normal temperature and pressure.

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

(1) The functional material can realize the advantages of low price, high reactivity, and normal temperature and pressure activation without using precious metals and expensive metal elements. Catalytic oxidation of formaldehyde at room temperature, the conversion rate of formaldehyde can be as high as 97%.

(2) The functional material can be made into a variety of forms, including solid and liquid, and is not afraid of water or humidity, and has low requirements on the use environment, so it can be used in a wide range of scenarios.

(3) The functional material can be used directly without being made into a module or relying on equipment, the conditions of use are extremely simple, the operation is extremely simple, and it is easy for non-professionals to use.

(4) The functional material can not only catalyze the oxidation of formaldehyde, but also catalyze the oxidation of various VOCs. Catalytic oxidation of benzene at room temperature, the conversion rate of benzene can be as high as 54%. Combined with the advantages of high reactivity and normal temperature and pressure activation of the functional material, the material can have an obvious deodorizing effect indoors and in the car after use, and can be sensed by the sense of smell without complicated instruments and meters.

(5) Before and after the functional material reacts with formaldehyde and VOCs, the color changes, which can be directly observed by naked eyes. The principle is that the material reacts with formaldehyde and VOCs to catalyze the oxidation reaction to generate new substances, and uses the difference in color between the reactant and the product itself to indicate the speed and degree of the reaction. This kind of visualization does not use the reaction intermediate product and the final product of the reaction to react with the added acid-base indicator to develop color, and does not depend on the effect of the acid-base indicator. Information indicating a change in the decontamination capability of a material.

Description of drawings

Fig. 1 is the graph of the removal efficiency of the functional material prepared in Example 1 as a function of time for the detection of formaldehyde catalytic oxidation by the Building Environment Testing Center of Tsinghua University.

Fig. 2 is a transmission electron microscope (TEM) photograph of the functional material prepared in Example 6.

Fig. 3 is a schematic diagram of the color change with time of the functional material prepared in Example 6 after reacting with formaldehyde.

Detailed ways

For better illustrating the present invention, facilitate understanding technical scheme of the present invention, typical but non-limiting embodiment of the present invention is as follows:

In the following examples, the method of sampling, testing and calculating the removal rate of formaldehyde refers to QB/T 27612006 "Method for Determination of Purification Effect of Indoor Air Purification Products". The sampling, test method and calculation method of removal rate of benzene refer to JC/T 1074-2008 "Purification performance of coating materials with indoor air purification function".

Example 1

Weigh 23.5g of white carbon black, 17.2g of titanium dioxide, and 46.5g of activated carbon, mix and stir evenly, and heat in a muffle furnace at 850°C for 12h to form a loading agent. In the hydrochloric acid ethanol solution containing 13.1g nickel sulfate (catalyst), 4g cobalt nitrate (catalyst), 2.1g nitric acid (oxidizing agent), add 1.5g potassium aluminum sulfate (strengthening agent), 1.1g sodium phosphate (ligand), use Adjust the pH to 9 and the temperature to 55°C with 0.2-2mol/L ammonia water, so that there is just precipitation in the solution, then add the loading agent, adjust the pH to 5 with 0.1-3mol/L citric acid, and place it in a 95°C water bath After stirring for 24 hours, a precipitate was slowly formed, left to age, and the solid was separated. The solid was washed, dried, and then calcined in a muffle furnace at 1000°C for 10 hours under a nitrogen atmosphere to obtain a functional material for visually degrading formaldehyde and VOCs at normal temperature and pressure. The prepared material will change from black to yellow-brown after reacting with formaldehyde and VOCs at normal temperature and pressure, and the removal efficiency of formaldehyde reaches 92.5%.

In a 3 cubic meter experimental cabin, the initial concentration of formaldehyde is 1 mg/m ³ under normal temperature and pressure. The concentration of formaldehyde in the cabin was measured within 1 hour. The reaction rate of this material is shown in Table 1:

Table 1 example material reaction data within 1 hour

Response time (min)	5	10	30	60
Formaldehyde removal rate (%)	87.3	89.1	90.7	92.5

Preparation of Comparative Material 1: Comparative Material 1 was prepared by the above-mentioned method. The only difference between Comparative Material 1 and the material prepared in Example 1 above is the lack of reinforcing agent potassium aluminum sulfate.

A comparative test was done in two identical 3 cubic meter chambers to demonstrate the effect of the reinforcing agent.

Experiment A: At normal temperature and pressure, the initial concentration of formaldehyde is 1 mg/m ³ . The concentration of formaldehyde in the cabin was measured at 5 minutes.

Experiment B: At normal temperature and pressure, the initial concentration of benzene is 1.276 mg/m ³ . The concentration of benzene in the chamber was measured after 24 hours.

The test results are shown in Table 2:

The reaction effect contrast of table 2 example material 1 and contrast material 1

the	Example material 1	Comparative material 1
5min removal efficiency of formaldehyde (%)	87.3	1.3
24h benzene removal efficiency (%)	80.3	1.2

From the above data, it can be seen that the key to the efficient removal of VOC in the present invention is also the enhancer. The formaldehyde removal rate can reach 87.3% in 5 minutes, which is quite superior.

Example 2

Weigh 21.8g of perlite, 19.6g of calcium carbonate, and 15.8g of kaolin, mix and stir evenly, and heat in a muffle furnace at 900°C for 15h to form a loading agent. In the sulfuric acid ethanol solution containing 16.2g ferric chloride (catalyst), 15.8g potassium dichromate (oxidant), 16.2g cobalt sulfate (catalyst), add 0.11g sodium tartrate (strengthening agent), 2.5g sodium borate (formulation Body), use 0.1～2mol/L sodium hydroxide solution to adjust pH=9-10 and temperature 80°C, so that there is just precipitation in the solution, then add loading agent, adjust pH= with 0.1～0.5mol/L hydrochloric acid 5.5, placed in a water bath at 80°C and stirred for 12 hours, left to age, and the solid was separated. The solid was washed, dried, and then calcined in a muffle furnace at 800°C for 12 hours under a nitrogen atmosphere to obtain a functional material for visually degrading formaldehyde and VOCs at normal temperature and pressure. The prepared material will change from purple to black after reacting with formaldehyde and VOCs at normal temperature and pressure, and the removal efficiency of formaldehyde reaches 96%.

Example 3

Weigh 5.9g of diatomaceous earth, 4.6g of zeolite, 3.1g of gypsum, and 35g of barium sulfate, mix and stir evenly, and heat in a muffle furnace at 1000°C for 24h to form a loading agent. In the hydrochloric acid aqueous solution containing 15.7g iron sulfate (catalyst), 0.09g potassium permanganate (oxidant), 2.3g zinc nitrate (catalyst), add 5.3g sodium pyrophosphate (strengthener), 18g potassium phosphate (ligand) , use 0.2-2mol/L sodium bicarbonate solution to adjust pH=8-9 and temperature 70°C, so that there is just precipitation in the solution, then add loading agent, adjust pH=4 with 0.1-2mol/L acetic acid, set Stir in a water bath at 95°C for 24h, let it stand for aging, and separate the solid. The solid was washed, dried, and then calcined in a muffle furnace at 1000°C for 10 hours under a nitrogen atmosphere to obtain a functional material for visually degrading formaldehyde and VOCs at normal temperature and pressure. The prepared material will change from purplish red to earthy yellow after reacting with formaldehyde and VOCs at normal temperature and pressure, and the removal efficiency of formaldehyde reaches 99%. Dissolve the above materials in 0.2mol/L hypochlorous acid solution, and stir magnetically at 80°C for 24 hours to obtain a functional liquid material for visually degrading formaldehyde and VOCs at room temperature and pressure. The prepared material is mixed with formaldehyde and VOCs at room temperature and pressure After the reaction, it will gradually change from liquid to solid, and the removal efficiency of formaldehyde reaches 99%.

Example 4

Weigh 17.2g of clay, 2.5g of mica, 1.1g of magnesium sulfate, and 3.2g of talc, mix and stir evenly, and heat in a muffle furnace at 900°C for 18h to form a loading agent. In the hydrochloric acid ethanol solution containing 15.3g of molybdenum nitrate (catalyst), 13.1g of lead dioxide (oxidant), 5.7g of lanthanum nitrate (catalyst), add 7g of potassium aluminum sulfate (reinforcing body), 12.7g of sodium oxalate (ligand) , use sodium hydroxide solution to adjust pH = 11 and temperature 90°C, so that there is just precipitation in the solution, then add loading agent, adjust pH = 5-6 with 0.1-2mol/L acetic acid, place in 85°C water bath and stir 10h, standing and aging, and the solid was separated. The solid was washed, dried, and then calcined in a muffle furnace at 1000°C for 8 hours under a nitrogen atmosphere to obtain a functional material for visually degrading formaldehyde and VOCs at normal temperature and pressure. The prepared material will change from purple red to earthy yellow after reacting with formaldehyde and VOCs at normal temperature and pressure, and the removal efficiency of formaldehyde reaches 99%.

Example 5

Weigh 11.4g of calcium carbonate, 50g of diatomaceous earth, 44g of graphite, and 15g of zeolite, mix and stir evenly, and heat in a muffle furnace at 950°C for 24h to form a loading agent. Add 2.7g calcium phosphate (strengthener), 20.7g Water (ligand), use sodium carbonate to adjust pH=6.5-8 and temperature 55°C, so that there is just precipitation in the solution, then add loading agent, adjust pH=2-3 with 0.1-2mol/L acetic acid, place Stir in a water bath at 80°C for 10 h, let it stand for aging, and separate the solid. The solid was washed, dried, and then calcined in a muffle furnace at 1500°C for 12 hours under a nitrogen atmosphere to obtain a functional material for visually degrading formaldehyde and VOCs at normal temperature and pressure. The prepared material will change from purple to brown after reacting with formaldehyde and VOCs at normal temperature and pressure, and the removal efficiency of formaldehyde reaches 99.3%. Dissolve the above materials in 0.5 mol/L sulfuric acid solution, and stir magnetically at 50°C for 12 hours to obtain a functional liquid material for visually degrading formaldehyde and VOCs at normal temperature and pressure. The prepared material will gradually change from liquid to solid after reacting with formaldehyde and VOCs at normal temperature and pressure, and the removal efficiency of benzene can reach 54%.

Example 6

Weigh 50g of diatomaceous earth and heat in a muffle furnace at 850°C for 12h to form a loading agent. Add 0.2g potassium aluminum sulfate ( Enhancer), 12g of water (ligand), adjust pH=8 and temperature 60°C with sodium carbonate, so that there is just precipitation in the solution, then add loading agent, adjust pH=3 with 0.1mol/L hydrochloric acid, place Stir in a water bath at 80°C for 10 h, let it stand for aging, and separate the solid. The solid was washed, dried, and then calcined in a muffle furnace at 1000°C for 12 hours under a nitrogen atmosphere to obtain a functional material for visually degrading formaldehyde and VOCs at normal temperature and pressure. Its transmission electron microscope (TEM) photo is shown in Figure 2. It can be seen from the figure that multi-metal active sites are formed by co-precipitation-gel reaction with multi-metal solution as a precursor. At the same time, gas expansion occurs during the reaction, and microbubbles are generated to form a large number of pores and void structures, so that a single reactant molecule such as formaldehyde and VOCs will be adsorbed by multiple active sites in the pores of the carrier. When a single molecule is captured and adsorbed by an active center, it will be additionally adsorbed by the adjacent active center, resulting in a significant change in the adsorption entropy, and a change in the transition state structure of the molecular activation, thereby changing the reaction path and causing the active center to go up. The actual reaction activation energy of the reaction to generate intermediate cracking products is lower and the transition state is more stable, which greatly improves the reaction efficiency, making the material capable of degrading formaldehyde and VOCs at normal temperature and pressure. The prepared material will change from purple red to earthy yellow after reacting with formaldehyde and VOCs at normal temperature and pressure, and the removal efficiency of formaldehyde reaches 99%. Fig. 3 is a schematic diagram of the color change with time of the functional material prepared in Example 6 after reacting with formaldehyde. The experimental conditions are to add 10g of functional materials into a transparent plastic tank, then add 1g of formalin solution with a mass concentration of 10%, cover the lid, and shake it vigorously from side to side for several times, so that the prepared material is in full contact with the formalin solution . A is the original color of the prepared material before the reaction (purple red, the time point is recorded as 0s). B is the color after adding formalin solution and shaking for 1 min, which is rose red. The color of C after adding formalin solution and shaking for 2 minutes is maroon. D is the color after adding the formalin solution and shaking for 3 minutes, which is khaki, which is also the color of the reaction end point. Therefore, the visualization of color changes can directly reflect and judge the reaction speed and degree of removal of formaldehyde and VOCs.

The applicant declares that the present invention illustrates the detailed composition and preparation method of the material described in the present invention through the above examples, but the present invention is not limited to the above detailed composition preparation method, that is, it does not mean that the present invention must rely on the above detailed composition preparation method success can be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of each raw material and method of the product of the present invention, addition, deletion of auxiliary components, selection of specific methods, etc., all fall within the scope of protection of the present invention and within the public domain.

Claims (13)

1. A functional material for visually degrading formaldehyde and VOCs at normal temperature and pressure, characterized in that it includes a loading agent, an oxidizing agent, a catalyst, a reinforcing agent and a ligand;

   The loading agent is one or more of the inorganic carrier; preferably, the loading agent is activated carbon, white carbon black, calcium carbonate, asbestos, diatomaceous earth, kaolin, perlite, barium sulfate, titanium dioxide, One or more of talc, gypsum, mica, graphite, zeolite, magnesium sulfate or clay;

   The oxidizing agent is an oxidizing substance with a standard hydrogen electrode potential greater than zero;

   The catalyst is a catalytically active element, inorganic compound or organic compound of a non-noble transition metal;

   The enhancer is one or more of potassium aluminum sulfate, sodium tartrate, calcium phosphate or sodium pyrophosphate;

   The ligands are atoms, molecules or ions that can bond with metal atoms.
2. The functional material for visually degrading formaldehyde and VOCs at normal temperature and pressure according to claim 1, characterized in that, based on the mass of the functional material as 100%, the mass percentage of the loading agent is 20-80%, and the oxidizing agent The mass percentage occupied by the catalyst is 0.1-25%; the mass percentage of the catalyst is 0.1-30%; the mass fraction percentage of the enhancer is 0.1-10%; the mass fraction percentage of the ligand is 1-20% .
3. The functional material for visually degrading formaldehyde and VOCs at normal temperature and pressure according to claim 1, wherein the oxidizing agent contains positive divalent copper, positive trivalent cobalt, positive tetravalent nickel, positive tetravalent manganese, permanganate radical MnO ₄ ^- , dichromate Cr ₂ O ₇ ^2- , ferrate FeO ₄ ^2- , tetravalent lead compound or sulfuric acid H ₂ SO ₄ , nitric acid HNO ₃ , bromine Br ₂ , perchloric acid HClO ₄ , hypochlorous acid HClO or One or a combination of hydrogen peroxide H ₂ O ₂ .
4. The functional material for visually degrading formaldehyde and VOCs at normal temperature and pressure according to claim 1, wherein the catalyst is vanadium, cobalt, iron, chromium, manganese, nickel, molybdenum, lanthanum, cadmium, copper or zinc. One or a combination of oxides or their salts.
5. The functional material for visually degrading formaldehyde and VOCs at normal temperature and pressure according to claim 1, wherein the ligand is selected from the group consisting of water, chloride ions, borate ions, phosphate ions, oxalate ions, formed salts Or one or more of them in the solution.
6. The present invention also provides a method for preparing the functional material according to any one of claims 1-5, characterized in that it comprises the following steps:

   (1) Adding enhancer and ligand to the solution containing oxidizing agent and catalyst, by adjusting pH and temperature, just have precipitation to separate out in the solution, obtain loading liquid;

   (2) dispersing the loading agent in the loading liquid, and slowly forming a precipitate by adjusting the pH to obtain a solid-liquid mixture;

   (3) After the solid-liquid mixture is left to age, the solid is separated to obtain the obtained product.
7. preparation method according to claim 6, is characterized in that, described preparation method also comprises:

   (4) dissolving the solid obtained in step (3) in a solvent to obtain a liquid material; the solvent is one or more of water, ethanol-water solution, hypochlorous acid, sulfuric acid, and hydrochloric acid.
8. The preparation method according to claim 7, characterized in that the mass ratio of ethanol to water in the ethanol-water solution is 1:7, the concentration of hypochlorous acid is 0.01-0.5mol/L, and the concentration of sulfuric acid is 0.1-1mol/L , The concentration of hydrochloric acid is 0.05～3mol/L.
9. The preparation method according to claim 6, characterized in that the loading agent is calcined at a temperature of 700-1200°C.
10. The preparation method according to claim 6, characterized in that step (3) also includes the steps of washing, drying, and activating the obtained solid, the drying temperature is 40-130°C; the roasting conditions are: in an inert atmosphere Baking at 800~1500℃ under the condition.
11. The application of the functional material described in any one of claims 1-5 in absorbing and/or degrading formaldehyde and/or VOCs.
12. The application according to claim 11, characterized in that, absorbing and/or degrading formaldehyde and/or VOCs at normal temperature and pressure.
13. A product for gas purification, characterized in that it contains the functional material described in any one of claims 1-5.

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