Photocatalytic paper and preparation method thereofTechnical Field
The invention relates to the field of inorganic non-metallic materials and environment-friendly materials, in particular to photocatalytic paper and a preparation method thereof.
Background
The photocatalytic material is one of key environment-friendly materials for deeply purifying organic pollutants, ammonia nitrogen, bacteria and viruses in indoor air, has the advantages of environmental protection, no toxicity, harmlessness, good effect on human bodies and the like compared with an adsorption material and a sterilization material, but also has the trouble of inconvenient use and the need of making a spray for indoor and in-vehicle spray construction after decoration. Therefore, it is a key technical problem to solve these problems that the photocatalyst is supported on a certain carrier to be manufactured into articles for indoor and car use.
Paper is the most common article in our daily life, and is in contact with paper when reading books and newspapers, or writing and drawing. Paper is also not available in industrial, agricultural and defense industry.
Paper is a sheet-like fibrous product used for writing, printing, drawing, packaging, or the like. The plant fiber pulp is produced by combining water suspension of plant fiber after pulping treatment on a net in a staggered manner, preliminarily dewatering, compressing and drying. China is the world in which paper was invented the earliest. According to archaeological findings, in the period of Western Han dynasty (206-8 years before the Gongyuan), China already has hemp fiber paper.
Examples of the paper to be produced by a general machine include printing paper, wrapping paper, drawing paper, electrical insulating paper, blotting paper, sheet paper, decorative paper, note paper, filter paper, and special processed paper. The manufacturing method varies according to the use scenario and the quality requirement.
Modern paper making processes can be divided into the main steps of pulping, modulation, papermaking, processing and the like. Pulping is the first step of papermaking and generally there are three methods for converting wood into pulp, mechanical pulping, chemical pulping and semi-chemical pulping. The modulation of paper stock is another key point of papermaking, and the strength, the color tone and the printing quality of the finished paper and the storage life of the paper are directly related to the modulation of paper stock. The main work of papermaking is to uniformly interweave and dehydrate thin paper stock, and then to dry, press polish, roll paper, cut, sort and package the paper stock. And finally, manually or mechanically selecting the paper with the damage or stain, and finally packaging every five hundred sheets into one package.
Paper is a type of microscopically porous material. If the photocatalyst can be loaded on paper, it is possible to realize the functions of loading the photocatalyst on a porous material, degrading pollutants in the air by a photocatalytic reaction on a large surface area and resisting bacteria and viruses.
Disclosure of Invention
The invention aims to provide a preparation method of photocatalytic paper, which firmly coats a supported nano photocatalyst on the surface of paper fiber, and the obtained product has air purification function with photocatalytic performance due to the porosity of paper and the adsorbability of the supported nano photocatalyst to organic pollutants and bacteria and viruses in air.
The technical scheme of the invention is as follows: the photocatalytic paper comprises dry paper pulp and a photocatalyst (the invention adopts 'Lujie' brand photocatalyst, a conventional commercial product), wherein the mass percent of the dry paper pulp is 75-91%, the mass percent of the photocatalyst is 9-25%, and particles of the photocatalyst are uniformly distributed in the interior and on the surface of paper formed by the dry paper pulp.
The invention also provides a preparation method of the photocatalytic paper, which comprises the following steps:
s1, grinding the photocatalyst, and simultaneously adding a surface modifier and a dispersion anti-settling agent to obtain photocatalyst slurry;
s2, pouring the photocatalyst slurry obtained in the step S1 into a paper pulp-water system, and stirring and dispersing to obtain paper pulp slurry;
s3, adding water into the pulp slurry obtained in the step S2 for dilution, then performing dispersion treatment, and adding a retention aid;
s4, papermaking is carried out on the mixture processed in the step S3, and the papermaking wet paper is dehydrated, compacted, dried and rolled to obtain the photocatalytic paper.
Further, the photocatalyst in S1 is a commercially available titania-supported silica photocatalyst as a raw material, and the main components thereof include titania and silica; the fineness of the ground photocatalytic material is 200-1250 meshes.
Further, the grinding in the step S1 is performed by a wet grinding method, and the ratio of the photocatalyst to water is 1: grinding at a ratio of 0.5-1.5 until the average particle size of the photocatalytic material is 3-8 microns and the maximum particle size is less than 45 microns.
Further, the dispersion anti-settling agent used in the step S1 is one of sodium polyacrylate, sodium hexametaphosphate and sodium polycarboxylate, and the amount of the dispersion anti-settling agent is 0.01-0.8% of the mass of the photocatalyst; the used surface modifier is a silane coupling agent or a phthalate coupling agent or fatty alcohol-polyoxyethylene ether, and the dosage of the surface modifier is 0.1-2.0% of the mass of the photocatalyst.
Further, the paper pulp in the step S1 is wood pulp, straw pulp, hemp pulp, reed pulp, cane pulp, bamboo pulp, rag pulp or a mixture thereof formed by any proportion.
Further, in step S2, the photocatalyst slurry: pulp: the mass ratio of water is 1: 3-10: 30-100, and the stirring and dispersing time is 1-4 h.
Further, in the above step S3, the pulp slurry: the mass ratio of water is 1: 30-200 parts of; the retention aid is polyacrylamide, and the dosage of the retention aid is 0.01-1% of the mass of the paper pulp.
Further, in the step S4, the drying is carried out at 80-120 ℃ until the paper quality is 30g/m2-120g/m2。
The preparation method comprises the following steps: the first step is as follows: the photocatalyst with the fineness of 200-1250 meshes is used as a raw material, and is mixed with a surface modifier, a dispersion anti-settling agent and water according to a mass ratio of 1: (0.001-0.02): (0.0001-0.008): (0.5-1.5) mixing, and grinding by using a grinding system of a wet stirring mill; controlling the temperature of a grinding system to be not higher than 80 ℃ in the grinding process; grinding until the average particle size is 3-8 microns and the maximum particle size is less than 45 microns to obtain slurry; the second step is that: pouring the slurry prepared in the first step into a paper pulp-water medium system, wherein the mass ratio of the slurry to the paper pulp to the water is 1: (3-10): (30-100) mixing, and dispersing in a strong stirring disperserDispersing and stirring for 1-4 h; the third step: adding water to dilute the paper pulp slurry prepared in the second step, wherein the paper pulp, the retention aid and the water are mixed according to the mass ratio of 1: (0.0001-0.01): (30-200) mixing and dispersing; the fourth step: papermaking is carried out on the paper pulp dispersed in the third step, the wet papermaking is dewatered, compacted and dried at the temperature of 80-120 ℃, and the drying quality of the paper is controlled to be 30g/m2-120g/m2And the paper is wound on a winding machine, so that the paper with photocatalytic performance can be obtained.
In a preferred embodiment of the invention, the fineness of the raw material in the first step is 325-1000 meshes.
In a preferred embodiment of the present invention, in the first step, the surface modifier is one of a silane coupling agent, a phthalate coupling agent and peregal, and is preferably a silane coupling agent.
In a preferred embodiment of the present invention, the dispersion anti-settling agent in the first step is one of sodium polyacrylate, sodium hexametaphosphate and sodium polycarboxylate, and is preferably sodium polyacrylate.
In a preferred embodiment of the present invention, in the first step, the photocatalyst is mixed with the surface modifier, the dispersion anti-settling agent and water in a mass ratio of 1: (0.005-0.015): (0.003-0.005): (0.8 to 1.2).
In a preferred embodiment of the invention, the temperature of the grinding system in the first grinding process is not higher than 70 ℃, the average particle size after grinding is 4-5 microns, and the maximum particle size is less than 40 microns.
In a preferred embodiment of the invention, the pulp in the second step is wood pulp, straw pulp, hemp pulp, reed pulp, cane pulp, bamboo pulp, rag pulp or a mixture thereof in any proportion.
In a preferred embodiment of the present invention, the mass ratio of the slurry to the pulp and the water in the second step is 1: (5-8): (50-80).
In a preferred embodiment of the present invention, in the second step, the dispersion is performed in a strong stirring disperser for 2 to 3 hours.
In a preferred embodiment of the invention, the retention aid in the third step is polyacrylamide or a polyacrylamide emulsion.
In a preferred embodiment of the invention, the pulp in the third step is mixed with a retention aid and water in a mass ratio of 1: (0.002-0.005): (80 to 120)
In a preferred embodiment of the invention, the drying temperature in the fourth step is 80-105 ℃, and the dry mass of the paper is 50-80 g/m2。
Compared with the prior art, the invention has the advantages that:
the photocatalytic material used in the method takes a commercially available titanium dioxide-loaded silicon dioxide photocatalyst as a raw material, and the main components of the photocatalytic material are titanium dioxide and silicon dioxide, so that pollutants can be degraded under natural light, and the photocatalytic material has extremely high stability.
The method of the invention creatively utilizes the porous property, white property and fiber carrying property of the paper, the photocatalytic material is firmly loaded in the paper, and the paper is porous in a microcosmic scale, so that the active sites of the photocatalyst contacting with the pollutants can be increased, and the paper has the functions of degrading the pollutants such as formaldehyde, toluene and the like in the air and resisting bacteria and viruses, meanwhile, the used raw materials have no odor, the normal use of a user can be ensured, and the paper is convenient to use indoors and in a vehicle, is easy to store and can be placed in any place needing to degrade the air pollutants according to the requirements. The photocatalytic paper prepared by the method can be used as one of key materials for indoor air purification, and provides a new way for expanding the use of paper and solving the problem of indoor air purification.
Detailed Description
The present invention will be described in further detail below with reference to specific embodiments in order to make the present invention better understood by those skilled in the art.
Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art, and the raw materials used are commercially available.
Example 1
1. The preparation method comprises the following steps of taking a commercially available Lujie photocatalyst with the fineness of 200-325 meshes as a raw material, and mixing the Lujie photocatalyst with a phthalate coupling agent, sodium hexametaphosphate and water in a mass ratio of 1: 0.001: 0.0001: 0.5, mixing, and grinding by using a grinding system of a wet stirring mill; controlling the temperature of a grinding system to be not higher than 70 ℃ in the grinding process; grinding to an average particle size of 6-8 microns and a maximum particle size of less than 45 microns;
2. pouring the slurry prepared in the step 1) into a paper pulp-water medium system, wherein the mass ratio of the slurry to wood pulp to water is 1: 3: 30, mixing, and dispersing and stirring in a strong stirring dispersion machine for 1 hour;
3. diluting the paper pulp slurry prepared in the step 2) by adding water, wherein the paper pulp, the polyacrylamide emulsion and the water are mixed according to the mass ratio of 1: 0.0001: 30, mixing and dispersing;
4. dehydrating and compacting the dispersed paper pulp, and drying the wet paper at 10-20 ℃, wherein the drying quality of the paper is controlled at 30g/m2-50g/m2And the paper is wound on a winding machine, so that the paper with photocatalytic performance can be obtained.
The formaldehyde and toluene purification test is carried out according to the building material industry standard JC/T1074-2008, the formaldehyde purification efficiency is 78.1%, the formaldehyde purification effect durability is 75.4%, the toluene purification efficiency is 35.1%, and the toluene purification effect durability is 28.7%, and the result meets the technical index requirements of I-type materials in the standard JC/T1074-2008.
Example 2
1. Taking a commercially available Lujie brand photocatalyst with the fineness of 1000-1250 meshes as a raw material, and mixing the Lujie brand photocatalyst with peregal, sodium polycarboxylate and water in a mass ratio of 1: 0.02: 0.008: 1.5, mixing, and grinding by using a grinding system of a wet stirring mill; controlling the temperature of a grinding system to be not higher than 80 ℃ in the grinding process; grinding to an average particle size of 3-4 microns and a maximum particle size of less than 35 microns;
2. pouring the slurry prepared in the step 1) into a paper pulp-water medium system, wherein the mass ratio of the slurry to the straw pulp to the water is 1: 10: 100, mixing, and dispersing and stirring in a strong stirring dispersion machine for 4 hours;
3. diluting the paper pulp slurry prepared in the step 2) by adding water, wherein the paper pulp, the polyacrylamide and the water are mixed according to the mass ratio of 1: 0.01: 200, mixing, and performing dispersion treatment;
4. removing the dispersed paper pulp and wet paperWater, compacting and drying at 105-120 ℃, wherein the drying quality of the paper is controlled at 100g/m2-120g/m2And the paper is wound on a winding machine, so that the paper with photocatalytic performance can be obtained.
The formaldehyde and toluene purification test is carried out according to the building material industry standard JC/T1074-2008, the formaldehyde purification efficiency is 80.1%, the formaldehyde purification effect durability is 76.5%, the toluene purification efficiency is 35.4%, and the toluene purification effect durability is 29.6%, and the result meets the technical index requirements of I-type materials in the standard JC/T1074-2008.
Example 3
1. The method comprises the following steps of taking a commercially available Lujie photocatalyst with the fineness of 325-500 meshes as a raw material, and mixing the Lujie photocatalyst with a silane coupling agent, sodium polyacrylate and water in a mass ratio of 1: 0.008: 0.004: 1, mixing, and grinding by using a grinding system of a wet stirring mill; controlling the temperature of a grinding system to be not higher than 70 ℃ in the grinding process; grinding until the average particle size is 4-5 microns and the maximum particle size is less than 40 microns;
2. pouring the slurry prepared in the step 1) into a paper pulp-water medium system, wherein the mass ratio of the slurry to wood pulp to water is 1: 5: 50, mixing, and dispersing and stirring in a strong stirring dispersion machine for 3 hours;
3. diluting the paper pulp slurry prepared in the step 2) by adding water, wherein the paper pulp, the polyacrylamide and the water are mixed according to the mass ratio of 1: 0.003: 100, mixing, and performing dispersion treatment;
4. dewatering and compacting the dispersed paper pulp, and drying at 105 deg.C to obtain paper with dry quality of 80g/m2And the paper is wound on a winding machine, so that the paper with photocatalytic performance can be obtained.
Formaldehyde and toluene purification tests are carried out according to the building material industry standard JC/T1074-2008, the formaldehyde purification efficiency is 80.2 percent, the formaldehyde purification effect durability is 78.6 percent, the toluene purification efficiency is 35.6 percent, the toluene purification effect durability is 31.9 percent, and the result meets the technical index requirements of I-type materials in the standard JC/T1074-2008
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.