CN111004539A

CN111004539A - Preparation of titanium dioxide-loaded aqueous environment-friendly coating based on purified diatomite

Info

Publication number: CN111004539A
Application number: CN201911352025.7A
Authority: CN
Inventors: 胡胜勇; 蔡剑波; 吴少勇
Original assignee: Shenzhen Eli Home Eco Building Materials Co ltd
Current assignee: Shenzhen Eli Home Eco Building Materials Co ltd
Priority date: 2019-12-25
Filing date: 2019-12-25
Publication date: 2020-04-14

Abstract

The invention provides a titanium dioxide-loaded aqueous environment-friendly coating based on purified diatomite. The diatomite before and after loading is subjected to electron microscope standard, the purity of the diatomite is found to be greatly improved, and the nano titanium dioxide can be seen to be loaded in the diatomite pores by comparing the diatomite before and after loading by adopting an X-ray diffractometer (XRD). The water-based paint product prepared by purifying the diatomite loaded with the nano titanium dioxide can obviously improve the durability of the purification performance of toluene, and has the functions of antibiosis, mildew resistance, condensation resistance and the like.

Description

Preparation of titanium dioxide-loaded aqueous environment-friendly coating based on purified diatomite

Technical Field

The invention relates to the field of building materials, in particular to preparation of a water-based paint for effectively purifying diatomite, loading nanometer titanium dioxide and efficiently adsorbing and degrading methylbenzene.

Background

The diatomite is a sedimentary rock with a unique biological origin and a non-metallic mineral formed gradually by the remains of diatom growing in oceans or lakes deposited in the water bottom and acted by the natural environment. Has the advantages of large specific surface area, strong adsorbability, high porosity, high temperature resistance, stable chemical property, and fine, loose, light, porous, water-absorbing and permeable physical properties. The diatomite surface has numerous pores, and has the functions of regulating air humidity, adsorbing and eliminating harmful air and peculiar smell.

Due to the excellent specific surface area of the diatomite, the diatomite can be used as a coating additive to increase the volume and thicken and improve the adhesive force. In addition, the coating film has larger pore volume and macroporous structure, so that the drying time of the coating film can be shortened. The dosage of the resin can be reduced, and the cost is reduced. The nature of diatomaceous earth itself has led to the use of diatomaceous earth in a variety of coating systems. According to research, the diatomite in the coating can absorb and decompose substances harmful to human bodies, and the principle can be explained as follows: the diatomite in the wall material generates a waterfall effect by absorbing and releasing water in the environment, and water molecules can be decomposed into positive and negative ions. The water molecules are wrapped to form positive and negative ion groups, and then the water molecules are used as carriers and float in the air, so that the sterilization capability is realized. When the free positive and negative ion groups in the air contact with harmful microorganisms, the harmful microorganisms are immediately surrounded and isolated, and then the most active hydroxide ions in the positive and negative ion groups can perform violent chemical reactions with the harmful substances, and finally decompose the harmful substances into micromolecular water or other non-toxic inorganic substances.

Due to the forming characteristics of diatomaceous earth, diatomaceous earth is often associated or symbiotic with Fe₂O₃、Al₂O₃CaO, MgO and the like

The substances and organic matters are contained among the diatom shells, filled in the pores of the diatom shells or attached to the surfaces of the diatom shells, and influence the adsorption and degradation of harmful substances by the diatomite. Functional materials capable of decomposing harmful substances such as formaldehyde, toluene and the like are added into the existing paint products, but the materials cannot be well and stably dispersed in gaps of an adsorption material, which is an important reason that the decomposed harmful gases are weak and the persistence is reduced. So that economic and effective purification of the existing diatomite is of great importance for improving the water-based diatomite product.

The existing diatomite purifying technology comprises acid leaching method and scrubbingMethods, roasting methods, synthesis methods, and the like. In the existing research, a pickling method is used more frequently, and the purer diatomite is obtained by mixing a mixed solution of hydrofluoric acid and concentrated sulfuric acid with the diatomite according to a certain proportion, performing filter pressing, washing and drying. However, in industrial production, the acid washing method not only has high cost and more complex process, but also generates waste acid which is difficult to treat, increases the potential safety hazard of environmental protection, and the main component SiO in the diatomite₂The structure is easy to be destroyed, so that the acid washing method is not suitable for large-scale production and use. According to the invention, the diatomite is treated by adopting a roasting method, the diatomite structure is easy to damage by adopting different conventional high-temperature roasting at over 600 ℃, and the most suitable purifying and roasting temperature for the diatomite is determined to be 500 ℃ by combining with the product. The method not only keeps the diatomite pore structure, but also achieves the effect of effectively removing organic matters covered on the diatomite pore structure, and has simple process and strong production operability.

Nano TiO2₂The photocatalyst is a common photocatalyst, has the characteristics of low cost, no toxicity, stability, high catalytic activity and the like, and can degrade organic pollutants. Usually ultra-fine nano TiO₂The size quantum effect of (2) can cause the blue shift of the absorption band of the absorption spectrum so as to improve the photocatalytic activity, but in the actual use process, the agglomeration phenomenon also occurs to influence the catalytic efficiency. In recent years, porous minerals are regarded as good supporting materials for solving the problem of agglomeration of nano materials, and a plurality of silicon hydroxyl groups and hydrogen bonds on the surface of diatomite can form binding energy with titanium dioxide, so that agglomeration and fixation of the titanium dioxide can be inhibited, and effective adsorption and degradation of harmful gases such as toluene and the like can be achieved.

In the existing diatom paint products, the aqueous liquid diatom paint is a liquid environment-friendly paint product which is prepared by taking water as a dispersion medium, utilizing excellent physical properties of diatomite containing a large number of micropores and combining with excellent construction properties of emulsion paint.

The reference is ① Guo, Xushiyong, preparation of nano titanium dioxide/diatomite composite material and photocatalytic performance research, inorganic salt industry, 2017,49 (4), ② willow, preparation of nano titanium dioxide/diatomite composite material and photocatalytic performance research, ③ Zhongting Ting and the like, the present situation and research progress of diatomite processing and utilization in China, mineral product protection and utilization, 2017,8 (4).

Disclosure of Invention

The invention aims to solve the technical problem of providing a multifunctional liquid diatomite coating which is efficient and durable, can adsorb and decompose harmful gases, simultaneously keeps the functions of the coating such as air humidity adjustment, mildew prevention, dewing prevention, fire prevention and the like, and is not limited by water sources and the technical requirements of construction personnel.

The technical scheme for solving the technical problems comprises three steps, wherein in the first step, firstly, the diatomite is purified, 35 parts of diatomite is put into a muffle furnace, the temperature is set at 500 ℃, and annealing is carried out after the temperature is raised to 500 ℃ and is kept for 5 minutes. After the temperature was reduced to room temperature, the diatomaceous earth was taken out of the muffle furnace.

And secondly, dropwise adding tetrabutyl titanate into absolute ethyl alcohol, and quickly stirring in a stirring barrel for 30 minutes to obtain a solution (a), and preparing a solution (b) from the absolute ethyl alcohol, deionized water and nitric acid according to the ratio of 10:1:0.2, wherein the pH value of the solution (b) is 2.2. The solution (a) was added dropwise to the solution (b) at a relatively slow rate, and 16 parts of the mixed liquid was taken and then 37 parts of diatomaceous earth was added, rapidly stirred for 4 hours, and aged for 12 hours. The resulting mixture was dried at 110 ℃ for 2 hours. Finally, the mixture is calcined at 500 ℃ for 1 hour.

And thirdly, respectively adding the diatom before and after purification and the purified diatomite loaded with the nano titanium dioxide into the coating, wherein the formula is shown in the following weight percentage.

27-37% of diatomite, 5-10% of attapulgite, 2-3% of zirconium phosphate silver-loaded powder, 3-4% of tourmaline powder, 3-5% of aluminum oxide, 0.2-0.5% of hydroxypropyl methyl cellulose, 20-30% of pure acrylic emulsion, 50400.3-0.7% of dispersing agent, 0.5-2% of 1, 2-propylene glycol, 0.1-0.3% of kasong, 0.1-0.3% of organic silicon defoaming agent and the balance of deionized water.

Compared with the diatomite before and after purification, the scanning electron microscope analysis can clearly show that most of impurities attached to the surface of the diatomite are effectively removed by calcining the diatomite, and microscopic diatomite cells of the diatomite are mainly in a disc shape and a cylinder shape. The pores of the diatomite are not obvious enough before calcination, the microcosmic ordered pore structure after calcination can be obviously seen, and the pore diameter is divided within 1 mu m. The diatomaceous earth loaded with titanium dioxide can be compared by an X-ray diffractometer (XRD) to see that the nano titanium dioxide is already loaded on the diatomaceous earth.

The average particle diameter D of the nano titanium dioxide₅₀Less than or equal to 30nm, and the hole of the diatomite is within 1 mu m. Making TiO by nanometer titanium dioxide under the action of ultraviolet rays in sunlight or lamplight₂Activating and generating free radicals with high catalytic activity, generating strong photooxidation and reduction capability, and catalyzing and photolyzing the toluene attached to the surface of an object. When toluene in the air is adsorbed by the nano titanium dioxide diatomite, the toluene can be decomposed in the pores. The reason is as follows: the diatomite has the capability of adsorbing harmful gases including formaldehyde in the air, but the diatomite does not have the capability of decomposing the harmful gases, so that the concentration of the harmful gases in the pores of the diatomite after full adsorption is far higher than that of the harmful gases in the air; the decomposition efficiency of the photocatalytic decomposition toluene is in direct proportion to the amount of the toluene contacted with the photocatalytic decomposition material, and the amount of the photocatalytic decomposition material and the amount of the toluene contacted with the photocatalytic decomposition material are far higher than that of the air in the diatomite pores, and the amount of the toluene decomposed by the photocatalytic decomposition material and the amount of the toluene contacted with the photocatalytic decomposition material are far higher than that of the air in the diatomite pores. Therefore, the decomposition efficiency of toluene is improved by the diatomite pore-supported TiO 2.

The invention takes the diatomite before and after purification and the diatomite loaded with nano titanium dioxide after purification to prepare the coating as comparison, and the preparation method of the coating comprises the following steps.

Weighing deionized water according to a certain proportion, putting the deionized water into a container, and then adding a dispersing agent 5040, 1, 2-propylene glycol, kasong and an organic silicon defoaming agent for dispersing.

Weighing the diatomite, the attapulgite, the zirconium phosphate-loaded silver powder, the tourmaline powder and the aluminum oxide according to the proportion, and adding the diatomite, the attapulgite, the zirconium phosphate-loaded silver powder, the tourmaline powder and the aluminum oxide into the dispersion liquid in the last step for continuous dispersion.

Weighing pure acrylic emulsion according to a certain proportion, continuously dispersing in the dispersion liquid, finally adding hydroxypropyl methyl cellulose to adjust the consistency, uniformly stirring, filling and packaging the liquid.

The invention is prepared by compounding various mineral materials such as natural microporous materials, inorganic functional materials and the like with aqueous emulsion, auxiliary agents and the like. As most of the materials of the product are inorganic materials and the fireproof material aluminium oxide is added, the product has the fireproof function. In addition, the product of the invention has the functions of improving air quality, adjusting air humidity, preventing mildew, preventing condensation, preventing fire and the like, and is not limited by water sources and the technical requirements of constructors.

Drawings

FIG. 1 is a Scanning Electron Microscope (SEM) image of diatomaceous earth before purification.

FIG. 2 is a Scanning Electron Microscope (SEM) image of purified diatomaceous earth.

FIG. 3 is an X-ray diffraction pattern (XRD) of purified diatomite-loaded nano titanium dioxide.

Detailed Description

Example 1

Weighing 16 parts of deionized water, putting the deionized water into a container, and then adding 0.7 part of dispersing agent 5040, 0.5 part of 1, 2-propylene glycol, 0.3 part of kasong and 0.3 part of organic silicon defoaming agent for dispersing; weighing 37 parts of untreated diatomite, 5 parts of attapulgite, 3 parts of zirconium phosphate-loaded silver powder, 2 parts of tourmaline powder and 5 parts of aluminum oxide, and adding the raw materials into the dispersion liquid for continuous dispersion; and finally, weighing 30 parts of pure acrylic emulsion, continuously dispersing in the dispersion liquid, adding 0.2 part of hydroxypropyl methyl fiber, uniformly stirring, and filling and packaging the liquid, namely the embodiment 1.

Example 2

Weighing 16 parts of deionized water, putting the deionized water into a container, and then adding 0.7 part of dispersing agent 5040, 0.5 part of 1, 2-propylene glycol, 0.3 part of kasong and 0.3 part of organic silicon defoaming agent for dispersing; weighing 37 parts of purified diatomite, 5 parts of attapulgite, 3 parts of zirconium phosphate-loaded silver powder, 2 parts of tourmaline powder and 5 parts of aluminum oxide, and adding the obtained product into the dispersion liquid for continuous dispersion; and finally, weighing 30 parts of pure acrylic emulsion, continuously dispersing in the dispersion liquid, adding 0.2 part of hydroxypropyl methyl fiber, uniformly stirring, and filling and packaging the liquid, namely the embodiment 2.

Example 3

Weighing 16 parts of deionized water, putting the deionized water into a container, and then adding 0.7 part of dispersing agent 5040, 0.5 part of 1, 2-propylene glycol, 0.3 part of kasong and 0.3 part of organic silicon defoaming agent for dispersing; weighing 37 parts of purified titanium dioxide-loaded diatomite, 5 parts of attapulgite, 3 parts of zirconium phosphate-loaded silver powder, 2 parts of tourmaline powder and 5 parts of aluminum oxide, and adding the obtained mixture into a dispersion liquid for continuous dispersion; and finally, weighing 30 parts of pure acrylic emulsion, continuously dispersing in the dispersion liquid, adding 0.2 part of hydroxypropyl methyl fiber, uniformly stirring, and filling and packaging the liquid, namely the embodiment 3.

In order to verify whether the product meets the standard requirements of GB18582-2009 synthetic resin emulsion interior wall coating and GB18582-2008 harmful substance limit in interior decoration and finishing material interior wall coating, a sample is sent to a third-party detection mechanism for detection, and the test results are summarized as follows.

In order to verify the toluene adsorption and decomposition performance of the product, the sample is sent to a third-party detection mechanism to be detected according to JC/T1074-2008 'indoor air purification function coating material purification performance', and the summary is as follows.

The test results show that the samples of the invention all accord with the relevant standards of environmental protection products, the diatomite coating loaded with titanium dioxide for purification can obviously improve the purification performance and purification durability of toluene, the purification performance is improved from 58% to 69%, the durable purification performance of toluene is improved from 39% to 47%, and the diatomite coating also has the functions of antibiosis, mildew resistance and dewing resistance.

Claims

1. The aqueous environment-friendly coating based on purified diatomite and loaded with titanium dioxide is characterized by being processed by adopting the following processing method:

A. adding water, a dispersing agent, an antifreezing agent, a preservative and a defoaming agent into a container for dispersing;

B. adding the purified diatomite and loaded titanium dioxide and filler according to the proportion, and adding the mixture into the dispersion liquid in the previous step for continuous dispersion;

C. adding the aqueous environment-friendly emulsion in proportion into the dispersion liquid for continuous dispersion, finally adding the thickening agent for adjusting the consistency, and uniformly stirring;

the dispersant is one of 5040 type dispersant and 5027 type dispersant;

the antifreezing agent is one of 1, 2-propylene glycol, 1, 3-propylene glycol and n-butyl alcohol;

the preservative is one or a combination of more of cason, LXE type preservative and BEK-560 type preservative;

the defoaming agent is an organic silicon defoaming agent;

the filler is one or a combination of more of calcium carbonate, kaolin, attapulgite, talcum powder, mica powder and titanium dioxide;

the water-based environment-friendly emulsion is one of water-based VAE emulsion, styrene-acrylic emulsion and pure acrylic emulsion;

the thickener is one or a combination of more of polyurethane thickener, hydroxypropyl methylcellulose and hydroxyethyl cellulose.

2. The purified diatomite-based titanium dioxide-loaded aqueous environment-friendly coating material as claimed in claim 1, wherein the purified diatomite-based titanium dioxide-loaded coating material is prepared by adopting the following method:

A. according to the invention, the diatomite is treated by adopting a roasting method, the purification and calcination temperature is 500 ℃, the calcination time is 5 minutes, and the purified diatomite is obtained after cooling;

B. dropwise adding tetrabutyl titanate into absolute ethyl alcohol, quickly stirring in a stirring barrel for 30 minutes to obtain a solution (a), and preparing the absolute ethyl alcohol, deionized water and nitric acid into a solution (b) according to the proportion of 10:1:0.2, wherein the pH value of the solution (b) is 2.2; dropping the solution (a) into the solution (b) at a slower rate;

C. taking 16 parts of the solution prepared in the previous step, adding 37 parts of the purified diatomite prepared in the previous step, quickly stirring for 4 hours, aging for 12 hours, drying the obtained mixture at 110 ℃ for 2 hours, and calcining at 500 ℃ for 1 hour;

the average particle size of the titanium dioxide is less than or equal to 30nm, and the pore size of the diatomite is within 1 mu m.