Environmentally friendly formaldehyde purifier and its preparation method and application

Abstract

The present invention belongs to the technical field of formaldehyde purification, and specifically relates to an environmentally friendly formaldehyde purifier and its preparation method and application. The preparation method comprises the following steps: (1) adding sepiolite into an acid solution, stirring, filtering, washing, and drying to obtain acid-treated sepiolite; (2) ultrasonically dispersing the acid-treated sepiolite, silver source, iron source, and neodymium source obtained in step (1) into deionized water to obtain a mixed solution, and then slowly dropping a sodium hydrogen phosphate solution into the mixed solution and stirring; then dropping an alkali solution to adjust the pH value of the mixed solution; then transferring to a hydrothermal reactor for hydrothermal reaction, filtering, washing, and drying to obtain a product A; (3) ultrasonically dispersing the product A, ferrous source, strontium source, cerium source, cobalt source, and tungstate obtained in step (2) into deionized water; hydrothermal reaction, filtering, washing, and drying to obtain a formaldehyde purifier. The formaldehyde purifier prepared by the present invention has excellent formaldehyde purification ability and excellent application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of formaldehyde purification, and more specifically, relates to an environmentally friendly formaldehyde purifier and a preparation method and application thereof. Background Art

[0002] With the continuous development of my country's economy, people's living standards have been greatly improved, and the pursuit of living environment quality and grade has been continuously improved, making the decoration of houses a trend in today's society. The use of various decorations, decoration materials and furniture containing more volatile organic compounds (VOC) is increasing, making the problem of indoor air pollution more and more serious. Formaldehyde is one of the most common and most harmful air pollutants to the human body. The World Health Organization has listed it as a carcinogenic and teratogenic substance. Therefore, solving the problem of indoor formaldehyde pollution has become a hot topic in the field of environmental materials research, and it is also an important research topic related to my country's people's livelihood and sustainable development. Among the many technologies for purifying indoor formaldehyde, semiconductor photocatalytic technology can completely mineralize formaldehyde molecules into harmless carbon dioxide and water molecules at room temperature, and has strong degradation ability and stable and sustainable. It is considered by researchers to be a green air purification technology with good development potential and application prospects.

[0003] CN111468172B discloses a metal oxide-silver bifunctional catalyst for formaldehyde waste gas purification and a preparation method thereof. The catalyst is composed of component A and component B, both of which are supported catalysts, wherein the active component of component A is an active metal oxide such as Fe, Mn, Co, Ce, etc., the active component of component B is Ag, and the carrier is an ordered mesoporous silicon material such as SBA-15, MCM-41, KIT-6, etc. Component A and component B are arranged in a layered filling or mechanical mixing manner. The loading amount of active metal oxide in component A is 3-10%. The loading amount of Ag in component B is 6-10%. The catalyst material used in the present invention is widely available and inexpensive, and the catalyst has good repeatability. The method can completely catalytically oxidize and remove formaldehyde at a relatively low temperature, has a low application cost, and has good industrial application potential.

[0004] CN115672268A discloses a formaldehyde adsorption degradation agent and a preparation method thereof, which is obtained by blending and crushing modified carbon fiber, tourmaline powder, vermiculite, aminosilane and mixed ester as raw materials; wherein the preparation method of the modified carbon fiber is to treat the carbon fiber with ozone and electric field and then modify the raw materials such as sulfonic acid and methoxysilane to obtain the formaldehyde adsorption degradation agent. The formaldehyde adsorption degradation agent prepared by the specific method of the present invention can generate a large amount of negative ions and has a strong purification ability for formaldehyde.

[0005] CN113144894B discloses a functional material for visual degradation of formaldehyde and VOCs at normal temperature and pressure, including a loading agent, an oxidant, a catalyst, a reinforcing agent and a ligand. The reaction efficiency is improved by the synergistic strengthening effect of the loading agent, the oxidant, the catalyst, the reinforcing agent and the ligand, so that the material has an excellent effect of degrading formaldehyde and VOCs at normal temperature and pressure, and before and after the reaction with formaldehyde and VOCs, the material's own structure and color change, and the reaction speed and degree can be directly observed and indicated by the naked eye. The material prepared by the present invention can not only degrade formaldehyde, but also degrade a variety of VOCs. Due to the synergistic strengthening effect, various components are evenly distributed and combined tightly, and are water-resistant and moisture-resistant. The material can be made into a solid or liquid state, which essentially solves the problems of performance attenuation and structural damage after the solid catalyst absorbs moisture. The present invention is used in the fields of environmental protection and health, and is particularly important for the treatment of polluted gases and industrial VOCs in space.

[0006] CN113042065B discloses a CoCa-OMS-2 nanowire catalyst for removing formaldehyde and a preparation method thereof, comprising CoCa and OMS, wherein CoCa is a manganese oxide octahedral molecular sieve doped with cobalt and calcium, and OMS is a manganese oxide octahedral molecular sieve; the mass ratio of cobalt element to manganese element is 0.5-8, and the added mass ratio of calcium is 2-10% of the manganese element. OMS-2 refers to manganese oxide octahedral molecular sieve, and CoCa-OMS-2 refers to manganese oxide octahedral molecular sieve doped with cobalt and calcium. It also includes cerium, vanadium, copper, magnesium, sodium, and potassium, which are all present in the form of oxides, and cerium, vanadium, copper, magnesium, sodium, and potassium are all doped in, and the proportion is generally 0.1-5%. The CoCa-OMS-2 nanowire catalyst for removing formaldehyde provided by the present invention and the preparation method thereof can effectively catalyze the oxidation of formaldehyde. During the room-temperature oxidative degradation of formaldehyde, during use, catalysts such as precious metals and manganese oxides can oxidize formaldehyde into carbon dioxide, thereby avoiding the problem of formaldehyde being oxidized into formic acid.

[0007] However, the purification time of the above-mentioned formaldehyde purifiers is relatively long or the purification capacity is limited, and the utilization rate of the purifiers is not high. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the defects and deficiencies in the prior art, and to provide an environmentally friendly formaldehyde purifier and its preparation method and application. The preparation method comprises the following steps: (1) adding sepiolite to an acid solution, stirring, filtering, washing, and drying to obtain acid-treated sepiolite; (2) ultrasonically dispersing the acid-treated sepiolite, silver source, iron source, and neodymium source obtained in step (1) into deionized water to obtain a mixed solution, and then slowly dropping a sodium hydrogen phosphate solution into the mixed solution and stirring; then dropping an alkali solution to adjust the pH value of the mixed solution; then transferring to a hydrothermal reactor for hydrothermal reaction, filtering, washing, and drying to obtain product A; (3) ultrasonically dispersing the product A, ferrous source, strontium source, cerium source, cobalt source, and tungstate obtained in step (2) into deionized water; hydrothermal reaction, filtering, washing, and drying to obtain a formaldehyde purifier. The formaldehyde purifier prepared by the present invention has excellent formaldehyde purification ability and excellent application prospects.

[0009] The purpose of the invention is to provide a method for preparing an environmentally friendly formaldehyde purifier.

[0010] Another object of the present invention is to provide an environmentally friendly formaldehyde purifier.

[0011] Another object of the present invention is to provide an application of an environmentally friendly formaldehyde purifier.

[0012] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0013] A method for preparing an environmentally friendly formaldehyde purifier, the method comprising the following steps:

[0014] (1) adding sepiolite to an acid solution, stirring for 8 to 16 hours, filtering, washing, and drying to obtain acid-treated sepiolite;

[0015] (2) ultrasonically dispersing the acid-treated sepiolite, silver source, iron source and neodymium source obtained in step (1) into deionized water to obtain a mixed solution, then slowly dropping a sodium hydrogen phosphate solution into the mixed solution and stirring for 20 to 40 minutes; then dropping an alkali solution to adjust the pH value of the mixed solution to 9 to 11; then transferring the mixed solution to a hydrothermal reactor for hydrothermal reaction, filtering, washing and drying to obtain a product A;

[0016] (3) Ultrasonic dispersion of the product A obtained in step (2), the ferrous source, the strontium source, the cerium source, the cobalt source and the tungstate in deionized water; followed by hydrothermal reaction at 180-220° C. for 16-26 h, filtering, washing and drying at 80-120° C. for 10-18 h to obtain a formaldehyde purifier.

[0017] Preferably, in step (1), the acid is hydrochloric acid, and the concentration of the hydrochloric acid is 2 to 4 mol / L.

[0018] Preferably, in step (1), the ratio of the sepiolite to the acid solution is 1 g: 20-30 mL; the drying is performed at 100-140° C. for 6-10 hours;

[0019] Preferably, in step (2), the silver source is silver nitrate; the iron source is at least one of ferric nitrate, ferric chloride and ferric acetate; and the neodymium source is at least one of neodymium nitrate, neodymium chloride and neodymium acetate.

[0020] Preferably, in step (2), the ratio of the acid-treated sepiolite, silver source, iron source, neodymium source and sodium hydrogen phosphate obtained in step (1) is: 1 g: 1.5 mmol: 0.01-0.03 mmol: 0.02-0.04 mmol: 0.5 mmol; and the alkali solution is 0.5-1.5 mol / L sodium hydroxide solution.

[0021] Preferably, in step (2), the hydrothermal reaction is carried out at 120-140° C. for 8-16 hours, and the drying is carried out at 80-120° C. for 10-18 hours.

[0022] Preferably, in step (3), the ferrous source is at least one of ferrous nitrate, ferrous chloride and ferrous acetate; the strontium source is at least one of strontium nitrate, strontium chloride and strontium acetate; the cerium source is at least one of cerium nitrate, cerium chloride and cerium acetate; the cobalt source is at least one of cobalt nitrate, cobalt chloride and cobalt acetate; the tungstate is sodium tungstate, potassium tungstate or ammonium tungstate.

[0023] Preferably, in step (3), the ratio of the product A obtained in step (2), the ferrous source, the strontium source, the cerium source, the cobalt source and the tungstate is 1 g: (0.5-xyz) mmol: x mmol; y mmol: z mmol: 0.5 mmol; x is 0.01 to 0.03; y is 0.005 to 0.015; and z is 0.015 to 0.025.

[0024] An environmentally friendly formaldehyde purifier prepared based on the above-mentioned method for preparing an environmentally friendly formaldehyde purifier.

[0025] Based on the application of the above-mentioned environmentally friendly formaldehyde purifier, the environmentally friendly formaldehyde purifier is used for formaldehyde purification.

[0026] The present invention has the following beneficial effects:

[0027] (1) The present invention improves the specific surface area of ​​sepiolite by selective treatment of sepiolite, and then improves the purification and degradation ability of formaldehyde by co-doping silver phosphate with iron and neodymium and loading it on the sepiolite;

[0028] (2) By co-doping iron tungstate with strontium, cerium and cobalt, the photocatalytic performance of iron tungstate is improved by utilizing the interaction between the components. In addition, there is a synergistic effect between the doped silver phosphate and the doped iron tungstate, which further degrades the purification capacity of formaldehyde.

[0029] (3) The preparation process of the present invention is simple, the raw material source is abundant, and it has excellent application prospects. DETAILED DESCRIPTION

[0030] The present invention is further described below with reference to specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0031] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0032] Example 1

[0033] A method for preparing an environmentally friendly formaldehyde purifier, the method comprising the following steps:

[0034] (1) Add 1 g of sepiolite to 25 mL of 3 mol / L hydrochloric acid solution, stir for 12 h, filter, wash, and dry at 120° C. for 8 h to obtain acid-treated sepiolite;

[0035] (2) 1 g of the acid-treated sepiolite obtained in step (1), 1.5 mmol of silver nitrate, 0.02 mmol of ferric nitrate and 0.03 mmol of neodymium chloride were ultrasonically dispersed in 50 mL of deionized water to obtain a mixed solution, and then 5 mL of 0.1 mol / L sodium hydrogen phosphate solution was slowly added dropwise to the mixed solution and stirred for 30 min; then 1 mol / L sodium hydroxide solution was added dropwise to adjust the pH value of the mixed solution to 10; then the mixed solution was transferred to a hydrothermal reactor, hydrothermally reacted at 130° C. for 12 h, filtered, washed, and dried at 100° C. for 14 h to obtain product A;

[0036] (3) 1 g of the product A obtained in step (2), 0.45 mmol of ferrous nitrate, 0.02 mmol of strontium chloride, 0.01 mmol of cerium acetate, 0.02 mmol of cobalt nitrate and 0.5 mmol of potassium tungstate were ultrasonically dispersed in 50 mL of deionized water; then hydrothermally reacted at 200° C. for 20 h, filtered, washed, and dried at 100° C. for 14 h to obtain a formaldehyde purifier.

[0037] Example 2

[0038] A method for preparing an environmentally friendly formaldehyde purifier, the method comprising the following steps:

[0039] (1) Add 1 g of sepiolite to 30 mL of 2 mol / L hydrochloric acid solution, stir for 16 h, filter, wash, and dry at 140° C. for 6 h to obtain acid-treated sepiolite;

[0040] (2) 1 g of the acid-treated sepiolite obtained in step (1), 1.5 mmol of silver nitrate, 0.03 mmol of ferric chloride and 0.02 mmol of neodymium acetate were ultrasonically dispersed in 50 mL of deionized water to obtain a mixed solution, and then 5 mL of 0.1 mol / L sodium hydrogen phosphate solution was slowly added dropwise to the mixed solution and stirred for 40 min; then 1.5 mol / L of sodium hydroxide solution was added dropwise to adjust the pH value of the mixed solution to 11; then the mixture was transferred to a hydrothermal reactor, hydrothermally reacted at 140° C. for 8 h, filtered, washed, and dried at 120° C. for 10 h to obtain product A.

[0041] (3) 1 g of the product A obtained in step (2), 0.44 mmol of ferrous chloride, 0.03 mmol of strontium acetate, 0.005 mmol of cerium nitrate, 0.025 mmol of cobalt chloride and 0.5 mmol of ammonium tungstate were ultrasonically dispersed in 50 mL of deionized water; then hydrothermally reacted at 220° C. for 16 h, filtered, washed and dried at 120° C. for 10 h to obtain a formaldehyde purifier.

[0042] Example 3

[0043] A method for preparing an environmentally friendly formaldehyde purifier, the method comprising the following steps:

[0044] (1) adding 1 g of sepiolite to 20 mL of 4 mol / L hydrochloric acid solution, stirring for 8 h, filtering, washing, and drying at 100° C. for 10 h to obtain acid-treated sepiolite;

[0045] (2) 1 g of the acid-treated sepiolite obtained in step (1), 1.5 mmol of silver nitrate, 0.01 mmol of ferric acetate and 0.04 mmol of neodymium nitrate were ultrasonically dispersed in 50 mL of deionized water to obtain a mixed solution, and then 5 mL of 0.1 mol / L sodium hydrogen phosphate solution was slowly added dropwise to the mixed solution and stirred for 20 min; then 0.5 mol / L of sodium hydroxide solution was added dropwise to adjust the pH value of the mixed solution to 9; then the mixed solution was transferred to a hydrothermal reactor, hydrothermally reacted at 120° C. for 16 h, filtered, washed, and dried at 80° C. for 18 h to obtain product A.

[0046] (3) 1 g of the product A obtained in step (2), 0.46 mmol of ferrous acetate, 0.01 mmol of strontium nitrate, 0.015 mmol of cerium chloride, 0.015 mmol of cobalt acetate and 0.5 mmol of sodium tungstate were ultrasonically dispersed in 50 mL of deionized water; then hydrothermally reacted at 180° C. for 26 h, filtered, washed and dried at 80° C. for 18 h to obtain a formaldehyde purifier.

[0047] Comparative Example 1

[0048] A method for preparing an environmentally friendly formaldehyde purifier, the method comprising the following steps:

[0049] (1) Add 1 g of sepiolite to 25 mL of 3 mol / L hydrochloric acid solution, stir for 12 h, filter, wash, and dry at 120° C. for 8 h to obtain acid-treated sepiolite;

[0050] (2) 1 g of the acid-treated sepiolite obtained in step (1), 1.5 mmol of silver nitrate and 0.05 mmol of ferric nitrate were ultrasonically dispersed in 50 mL of deionized water to obtain a mixed solution, and then 5 mL of 0.1 mol / L sodium hydrogen phosphate solution was slowly added dropwise to the mixed solution and stirred for 30 min; then 1 mol / L sodium hydroxide solution was added dropwise to adjust the pH value of the mixed solution to 10; then the mixed solution was transferred to a hydrothermal reactor, subjected to hydrothermal reaction at 130° C. for 12 h, filtered, washed, and dried at 100° C. for 14 h to obtain product A;

[0051] (3) 1 g of the product A obtained in step (2), 0.45 mmol of ferrous nitrate, 0.02 mmol of strontium chloride, 0.01 mmol of cerium acetate, 0.02 mmol of cobalt nitrate and 0.5 mmol of potassium tungstate were ultrasonically dispersed in 50 mL of deionized water; then hydrothermally reacted at 200° C. for 20 h, filtered, washed, and dried at 100° C. for 14 h to obtain a formaldehyde purifier.

[0052] Comparative Example 2

[0053] A method for preparing an environmentally friendly formaldehyde purifier, the method comprising the following steps:

[0054] (1) Add 1 g of sepiolite to 25 mL of 3 mol / L hydrochloric acid solution, stir for 12 h, filter, wash, and dry at 120° C. for 8 h to obtain acid-treated sepiolite;

[0055] (2) 1 g of the acid-treated sepiolite obtained in step (1), 1.5 mmol of silver nitrate and 0.05 mmol of neodymium chloride were ultrasonically dispersed in 50 mL of deionized water to obtain a mixed solution, and then 5 mL of 0.1 mol / L sodium hydrogen phosphate solution was slowly added dropwise to the mixed solution and stirred for 30 min; then 1 mol / L sodium hydroxide solution was added dropwise to adjust the pH value of the mixed solution to 10; then the mixed solution was transferred to a hydrothermal reactor, subjected to hydrothermal reaction at 130° C. for 12 h, filtered, washed, and dried at 100° C. for 14 h to obtain product A;

[0056] (3) 1 g of the product A obtained in step (2), 0.45 mmol of ferrous nitrate, 0.02 mmol of strontium chloride, 0.01 mmol of cerium acetate, 0.02 mmol of cobalt nitrate and 0.5 mmol of potassium tungstate were ultrasonically dispersed in 50 mL of deionized water; then hydrothermally reacted at 200° C. for 20 h, filtered, washed, and dried at 100° C. for 14 h to obtain a formaldehyde purifier.

[0057] Comparative Example 3

[0058] A method for preparing an environmentally friendly formaldehyde purifier, the method comprising the following steps:

[0059] (1) Add 1 g of sepiolite to 25 mL of 3 mol / L hydrochloric acid solution, stir for 12 h, filter, wash, and dry at 120° C. for 8 h to obtain acid-treated sepiolite;

[0060] (2) 1 g of the acid-treated sepiolite obtained in step (1), 1.5 mmol of silver nitrate, 0.02 mmol of ferric nitrate and 0.03 mmol of neodymium chloride were ultrasonically dispersed in 50 mL of deionized water to obtain a mixed solution, and then 5 mL of 0.1 mol / L sodium hydrogen phosphate solution was slowly added dropwise to the mixed solution and stirred for 30 min; then 1 mol / L sodium hydroxide solution was added dropwise to adjust the pH value of the mixed solution to 10; then the mixed solution was transferred to a hydrothermal reactor, hydrothermally reacted at 130° C. for 12 h, filtered, washed, and dried at 100° C. for 14 h to obtain product A;

[0061] (3) 1 g of the product A obtained in step (2), 0.45 mmol of ferrous nitrate, 0.03 mmol of strontium chloride, 0.02 mmol of cobalt nitrate and 0.5 mmol of potassium tungstate were ultrasonically dispersed in 50 mL of deionized water; then hydrothermally reacted at 200° C. for 20 h, filtered, washed and dried at 100° C. for 14 h to obtain a formaldehyde purifier.

[0062] Comparative Example 4

[0063] A method for preparing an environmentally friendly formaldehyde purifier, the method comprising the following steps:

[0064] (1) Add 1 g of sepiolite to 25 mL of 3 mol / L hydrochloric acid solution, stir for 12 h, filter, wash, and dry at 120° C. for 8 h to obtain acid-treated sepiolite;

[0065] (2) 1 g of the acid-treated sepiolite obtained in step (1), 1.5 mmol of silver nitrate, 0.02 mmol of ferric nitrate and 0.03 mmol of neodymium chloride were ultrasonically dispersed in 50 mL of deionized water to obtain a mixed solution, and then 5 mL of 0.1 mol / L sodium hydrogen phosphate solution was slowly added dropwise to the mixed solution and stirred for 30 min; then 1 mol / L sodium hydroxide solution was added dropwise to adjust the pH value of the mixed solution to 10; then the mixed solution was transferred to a hydrothermal reactor, hydrothermally reacted at 130° C. for 12 h, filtered, washed, and dried at 100° C. for 14 h to obtain product A;

[0066] (3) 1 g of the product A obtained in step (2), 0.45 mmol of ferrous nitrate, 0.03 mmol of cerium acetate, 0.02 mmol of cobalt nitrate and 0.5 mmol of potassium tungstate were ultrasonically dispersed in 50 mL of deionized water; then hydrothermally reacted at 200° C. for 20 h, filtered, washed, and dried at 100° C. for 14 h to obtain a formaldehyde purifier.

[0067] Comparative Example 5

[0068] A method for preparing an environmentally friendly formaldehyde purifier, the method comprising the following steps:

[0069] (1) Add 1 g of sepiolite to 25 mL of 3 mol / L hydrochloric acid solution, stir for 12 h, filter, wash, and dry at 120° C. for 8 h to obtain acid-treated sepiolite;

[0070] (2) 1 g of the acid-treated sepiolite obtained in step (1), 1.5 mmol of silver nitrate, 0.02 mmol of ferric nitrate and 0.03 mmol of neodymium chloride were ultrasonically dispersed in 50 mL of deionized water to obtain a mixed solution, and then 5 mL of 0.1 mol / L sodium hydrogen phosphate solution was slowly added dropwise to the mixed solution and stirred for 30 min; then 1 mol / L sodium hydroxide solution was added dropwise to adjust the pH value of the mixed solution to 10; then the mixed solution was transferred to a hydrothermal reactor, hydrothermally reacted at 130° C. for 12 h, filtered, washed, and dried at 100° C. for 14 h to obtain product A;

[0071] (3) 1 g of the product A obtained in step (2), 0.45 mmol of ferrous nitrate, 0.02 mmol of strontium chloride, 0.03 mmol of cerium acetate and 0.5 mmol of potassium tungstate were ultrasonically dispersed in 50 mL of deionized water; then hydrothermally reacted at 200° C. for 20 h, filtered, washed, and dried at 100° C. for 14 h to obtain a formaldehyde purifier.

[0072] Comparative Example 5

[0073] A method for preparing an environmentally friendly formaldehyde purifier, the method comprising the following steps:

[0074] (1) Add 1 g of sepiolite to 25 mL of 3 mol / L hydrochloric acid solution, stir for 12 h, filter, wash, and dry at 120° C. for 8 h to obtain acid-treated sepiolite;

[0075] (2) 1 g of the acid-treated sepiolite obtained in step (1), 1.5 mmol of silver nitrate, 0.02 mmol of ferric nitrate and 0.03 mmol of neodymium chloride were ultrasonically dispersed in 50 mL of deionized water to obtain a mixed solution, and then 5 mL of 0.1 mol / L sodium hydrogen phosphate solution was slowly added dropwise to the mixed solution and stirred for 30 min; then 1 mol / L sodium hydroxide solution was added dropwise to adjust the pH value of the mixed solution to 10; then the mixed solution was transferred to a hydrothermal reactor, hydrothermally reacted at 130° C. for 12 h, filtered, washed, and dried at 100° C. for 14 h to obtain product A;

[0076] (3) 1 g of the product A obtained in step (2), 0.45 mmol of ferrous nitrate, 0.02 mmol of strontium chloride, 0.03 mmol of cobalt nitrate and 0.5 mmol of potassium tungstate were ultrasonically dispersed in 50 mL of deionized water; then hydrothermally reacted at 200° C. for 20 h, filtered, washed and dried at 100° C. for 14 h to obtain a formaldehyde purifier.

[0077] Comparative Example 7

[0078] A method for preparing an environmentally friendly formaldehyde purifier, the method comprising the following steps:

[0079] (1) Add 1 g of sepiolite to 25 mL of 3 mol / L hydrochloric acid solution, stir for 12 h, filter, wash, and dry at 120° C. for 8 h to obtain acid-treated sepiolite;

[0080] (2) 1 g of the acid-treated sepiolite obtained in step (1), 1.5 mmol of silver nitrate, 0.02 mmol of ferric nitrate and 0.03 mmol of neodymium chloride are ultrasonically dispersed in 50 mL of deionized water to obtain a mixed solution, and then 5 mL of 0.1 mol / L sodium hydrogen phosphate solution is slowly added dropwise to the mixed solution and stirred for 30 min; then 1 mol / L sodium hydroxide solution is added dropwise to adjust the pH value of the mixed solution to 10; then the mixed solution is transferred to a hydrothermal reactor, subjected to hydrothermal reaction at 130° C. for 12 h, filtered, washed, and dried at 100° C. for 14 h to obtain an environmentally friendly formaldehyde purifier.

[0081] Comparative Example 8

[0082] A method for preparing an environmentally friendly formaldehyde purifier, the method comprising the following steps:

[0083] (1) Add 1 g of sepiolite to 25 mL of 3 mol / L hydrochloric acid solution, stir for 12 h, filter, wash, and dry at 120° C. for 8 h to obtain acid-treated sepiolite;

[0084] (2) 1 g of the acid-treated sepiolite obtained in step (1), 0.45 mmol of ferrous nitrate, 0.02 mmol of strontium chloride, 0.01 mmol of cerium acetate, 0.02 mmol of cobalt nitrate and 0.5 mmol of potassium tungstate were ultrasonically dispersed in 50 mL of deionized water; then hydrothermally reacted at 200° C. for 20 h, filtered, washed, and dried at 100° C. for 14 h to obtain a formaldehyde purifier.

[0085] Examples 1-3 and Comparative Examples 1-8 were used in the photocatalytic degradation of formaldehyde experiment, and the specific experimental steps were as follows:

[0086] The photocatalytic degradation performance of formaldehyde was evaluated using a continuous flow reactor under visible light irradiation at room temperature. First, 0.5 g of an environmentally friendly formaldehyde purification catalyst was weighed, coated in the middle of a 5 cm × 5 cm square plate, and placed in the center of the reactor. The ratio of formaldehyde gas and air flow was adjusted to obtain a certain concentration of formaldehyde gas, and the air flow rate was controlled to be 0.5 L / min. A 500 W xenon lamp was placed vertically on the reactor. Before irradiation, the square plate coated with the sample was kept in the dark for 60 min to achieve adsorption-desorption equilibrium. After the adsorption was completed, the light source was turned on. The concentration of residual formaldehyde at 20 min and 40 min was monitored by a formaldehyde gas analyzer. The degradation efficiency of the photocatalyst was calculated according to formula (1):

[0087] D=(C0-C t )×100% / C0; where D is the photocatalytic degradation efficiency, %; C0 is the initial mass concentration of formaldehyde, mol / L; C t is the mass concentration of formaldehyde after illumination t min, mol / L.

[0088] The specific results are shown in Table 1:

[0089] Table 1

[0090] Formaldehyde degradation rate at 20 minutes (%) Formaldehyde degradation rate at 40 min (%) Example 1 86.5 98.6 Example 2 85.1 97.3 Example 3 85.8 97.6 Comparative Example 1 82.4 94.6 Comparative Example 2 83.1 95.4 Comparative Example 3 82.9 95.2 Comparative Example 4 83.2 95.6 Comparative Example 5 82.5 94.9 Comparative Example 6 83.6 95.9 Comparative Example 7 63.4 74.1 Comparative Example 8 62.5 73.2

[0091] It can be seen from Table 1 that the environmentally friendly formaldehyde purifier prepared in the present application has excellent formaldehyde purification ability by utilizing the interaction between components. Therefore, the environmentally friendly formaldehyde purifier prepared in the present invention has excellent application prospects.

[0092] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing an environmentally friendly formaldehyde purifier, characterized in that: The preparation method comprises the following steps: (1) adding sepiolite into an acid solution, stirring for 8 to 16 hours, filtering, washing, and drying to obtain acid-treated sepiolite; (2) ultrasonically dispersing the acid-treated sepiolite, silver source, iron source and neodymium source obtained in step (1) into deionized water to obtain a mixed solution, then slowly dropping a sodium hydrogen phosphate solution into the mixed solution and stirring for 20 to 40 minutes; then dropping an alkali solution to adjust the pH value of the mixed solution to 9 to 11; then transferring the mixed solution to a hydrothermal reactor for hydrothermal reaction, filtering, washing and drying to obtain a product A; (3) ultrasonically dispersing the product A obtained in step (2), the ferrous source, the strontium source, the cerium source, the cobalt source and the tungstate into deionized water; then hydrothermally reacting at 180-220° C. for 16-26 h, filtering, washing and drying at 80-120° C. for 10-18 h to obtain a formaldehyde purifier; In step (2), the ratio of the acid-treated sepiolite obtained in step (1), the silver source, the iron source and the neodymium source, and the sodium hydrogen phosphate is 1 g: 1.5 mmol: 0.01-0.03 mmol: 0.02-0.04 mmol: 0.5 mmol; the alkali solution is a 0.5-1.5 mol / L sodium hydroxide solution; In step (2), the hydrothermal reaction is carried out at 120-140° C. for 8-16 hours, and the drying is carried out at 80-120° C. for 10-18 hours; In step (3), the ratio of the product A obtained in step (2), the ferrous source, the strontium source, the cerium source, the cobalt source and the tungstate is 1 g: (0.5-xyz) mmol: x mmol; y mmol: z mmol: 0.5 mmol; x is 0.01 to 0.03; y is 0.005 to 0.015; and z is 0.015 to 0.

025.

2. The method for preparing an environmentally friendly formaldehyde purifier according to claim 1, characterized in that: In step (1), the acid is hydrochloric acid, and the concentration of the hydrochloric acid is 2-4 mol / L.

3. The method for preparing an environmentally friendly formaldehyde purifier according to claim 1 or 2, characterized in that: In step (1), the ratio of the sepiolite to the acid solution is 1 g: 20-30 mL; and the drying is performed at 100-140° C. for 6-10 hours.

4. The method for preparing an environmentally friendly formaldehyde purifier according to claim 1, characterized in that: In step (2), the silver source is silver nitrate; the iron source is at least one of ferric nitrate, ferric chloride and ferric acetate; and the neodymium source is at least one of neodymium nitrate, neodymium chloride and neodymium acetate.

5. The method for preparing an environmentally friendly formaldehyde purifier according to claim 1, characterized in that: The iron source is at least one of ferric nitrate, ferric chloride and ferric acetate; the ferrous source is at least one of ferrous nitrate, ferrous chloride and ferrous acetate; the strontium source is at least one of strontium nitrate, strontium chloride and strontium acetate; the cobalt source is at least one of cobalt nitrate, cobalt chloride and cobalt acetate; the tungstate is sodium tungstate, potassium tungstate or ammonium tungstate.

6. An environmentally friendly formaldehyde purifier prepared according to the method for preparing an environmentally friendly formaldehyde purifier according to any one of claims 1 to 5.

7. The use of the environmentally friendly formaldehyde purifier according to claim 6, characterized in that: The environmentally friendly formaldehyde purifier is used for formaldehyde purification.