Nano composite material as well as preparation method and application thereof

Abstract

The invention discloses a nano composite material as well as a preparation method and application thereof. The preparation method of the nano composite material comprises the following steps: mixing tetrabutyl titanate and water, and dispersing for 1-4 hours to obtain hydrolysate; adding biochar with the persistent free radical content of 4.52 * 10 < 19 > spins.g <-1 >-6.81 * 10 < 19 > spins.g <-1 > into the hydrolysate, and continuously dispersing for more than 4 hours, preferably 5-10 hours; performing vacuum filtration and drying to obtain a precursor; and activating the precursor at high temperature for 2-5 hours in an inert atmosphere to obtain the nano composite material. The nano composite material provided by the invention has a remarkable decolorizing effect on AAS salt, has small chromaticity change under a long-term storage condition, and has excellent decolorizing stability.

Description

Technical Field

[0001] The invention relates to a nano composite material for decolorizing AAS salt, and in particular to a nano composite material and a preparation method and application thereof. Background Art

[0002] AAS salt, also known as sodium ethylenediamine sulfonate, is an important chemical raw material. Its main uses include as a chain extender and emulsifier for water-based polyurethane dispersions. In addition, it also has good emulsification, wetting, solubilization, dispersion, foaming and other properties, which make it more and more widely used in personal care products.

[0003] The conventional preparation method of AAS salt is to add ethylenediamine and chlorosulfonic acid into a reactor in a certain proportion, react at a suitable temperature, neutralize the obtained product with a sodium hydroxide solution, adjust the pH value to a suitable range, and purify it through distillation, crystallization and other steps to obtain AAS salt with higher purity.

[0004] However, continuous research has found that the AAS salt will change color and turn yellow during the production process. The color-changing substance has not yet been analyzed, but experimental analysis shows that the color change phenomenon mainly occurs in the purification unit. It is suspected that high-temperature purification causes some trace impurities in the product to change color. Conventionally, the product is decolorized by activated carbon adsorption, but the decolorization effect is not ideal. Even if the apparent color requirements are met after multiple decolorizations, the product will still change color during long-term storage, affecting the user experience of downstream customers and restricting production. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a nanocomposite material and a preparation method and application thereof.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a nanocomposite material comprises the following steps:

[0008] Tetrabutyl titanate and water were mixed and dispersed for 1 to 4 hours to obtain a hydrolyzate; the content of persistent free radicals was 4.52×10 19 spins·g -1 ~6.81×10 19 spins·g -1 The biochar is added to the above hydrolyzate and dispersed for more than 4 hours, preferably 5 to 10 hours; vacuum filtration and drying are performed to obtain a precursor;

[0009] Under an inert atmosphere, the precursor is activated at high temperature for 2 to 5 hours to obtain the nanocomposite material.

[0010] The inventors found in their research that the composite material of activated carbon and titanium dioxide has a significant decolorizing effect on yellowed AAS salt. At the same time, they unexpectedly found in their continued research that by activating and modifying the activated carbon, the content of persistent free radicals can be controlled within 4.52×10 19 spins·g -1 ~6.81×10 19 spins·g -1 In the range of 4.52×10 19 spins·g -1 ~6.81×10 19 spins·g -1 The composite material prepared with biochar within a certain range as raw material shows excellent AAS salt decolorization performance, while ensuring that the AAS salt still has a low chroma under long-term storage.

[0011] In some preferred examples of the present invention, the particle size of the biochar is less than 100 μm.

[0012] In some preferred examples of the present invention, the mass ratio of tetrabutyl titanate to biochar is 1:(8-12).

[0013] In some preferred examples of the present invention, the mixing mass ratio of tetrabutyl titanate and water is 1:(10-20).

[0014] In some preferred examples of the present invention, the dispersion method is ultrasonic dispersion.

[0015] In some preferred examples of the present invention, the high temperature activation temperature of the precursor is 500-1000°C, preferably 700-800°C.

[0016] In some preferred examples of the present invention, the biochar is pine needles, preferably selected from one or more of black pine needles, white pine needles, and red pine needles.

[0017] In the present invention, the content of persistent free radicals in the biochar can be controlled by any known method, such as high temperature pyrolysis, hydrothermal synthesis, etc., which is not further limited here, and further examples include the known methods disclosed in patents RO133405B1, CN116396770A, and CN114768761A, etc. Those skilled in the art are capable of adjusting or even accurately controlling the content of persistent free radicals in the biochar according to the methods disclosed in the known literature, and this will not be difficult.

[0018] The present invention also provides a nanocomposite material prepared by the method described above.

[0019] The present invention also provides an application of the nanocomposite material prepared by the method described above in decolorizing an AAS salt product.

[0020] The following is an example of a typical application:

[0021] A method for decolorizing an AAS salt product, comprising: mixing a 50 wt% AAS salt solution and the nanocomposite material according to any one of claims 1 to 6, stirring the mixture under ultraviolet irradiation, filtering, and recovering the decolorized AAS salt solution;

[0022] Preferably, the product chromaticity of the AAS salt solution is greater than 150 Hazen, preferably 180-250 Hazen;

[0023] Preferably, the mixing mass ratio of the AAS salt solution and the nanocomposite material is 1:(0.01-0.2);

[0024] Preferably, the illumination intensity of the ultraviolet irradiation is 50 to 200 lux, and the illumination time is 20 to 60 min.

[0025] The nano composite material provided by the invention has a significant decolorization effect on AAS salt, has a small chromaticity change under long-term storage conditions, and has excellent decolorization stability. DETAILED DESCRIPTION

[0026] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0027] In the present invention, the preparation method of AAS salt is as follows:

[0028] Add ethylenediamine and sodium 2-chloroethanesulfonate in a molar ratio of 8:1 into a reaction vessel, heat to 60°C, and stir at 100rpm for 3h. Use 32wt% sodium hydroxide solution to neutralize the reaction solution to pH 8. Perform vacuum distillation (5kPaA, 135°C) to remove excess ethylenediamine and water, and crystallize to obtain sodium ethylenediaminoethanesulfonate. Dissolve the product in water to obtain a 50wt% AAS salt solution, and the initial chromaticity of the solution is 238 Hazen.

[0029] Unless otherwise specified, other raw materials and reagents can be purchased from commercial sources.

[0030] The main equipment and testing methods used in the following embodiments of the present invention are:

[0031] The ultrasonic cleaning machine used was Ningbo Xinzhi SB-300DTY four-frequency ultrasonic cleaning machine;

[0032] A Wiggins overhead stirrer WB2000 M was used for stirring;

[0033] Drying was performed using Shanghai Puxia BGX-6050-TT explosion-proof vacuum drying oven;

[0034] The muffle furnace uses Shanghai Guangshu Electromechanical GSQ-2-1200-Ⅱ high temperature muffle furnace;

[0035] The ball mill uses Miqi YXQM planetary ball mill;

[0036] The content of persistent free radicals was detected using Bruker A300 EPR detection;

[0037] The decolorization reactor uses the 1T / D skid-mounted UV catalytic oxidation device from Lianyungang Wending Environmental Protection Technology;

[0038] The colorimetric analysis was performed using a German BYK LCS IV liquid colorimeter.

[0039] [Example 1]

[0040] (1) Preparation of biochar material: 100 g of black pine needles were washed several times with desalted water, dried at 80 °C, and ground into powder. The powder was kept at 100 °C for 1 h in a nitrogen atmosphere, and then pyrolyzed at 800 °C for 4 h. The persistent free radical content of the obtained biochar material was 4.52 × 10 19 spins·g -1 The biochar material is ball-milled to a particle size of less than 100 μm for later use.

[0041] (2) Preparation of nanocomposite materials: Tetrabutyl titanate and water were mixed at a mass ratio of 1:11.5, stirred for 1 hour, and then ultrasonically dispersed for 2 hours. The biochar material prepared in step (1) was added in an amount of 8 times the mass of tetrabutyl titanate, and ultrasonic dispersion was continued for more than 5 hours to uniformly disperse the system. Then, the mixture was vacuum filtered and dried to obtain a precursor; in a nitrogen atmosphere, the temperature was raised to 700°C at a heating rate of 3°C / min, and the precursor was activated at high temperature for 3 hours to obtain the nanocomposite material A.

[0042] [Example 2]

[0043] (1) Preparation of biochar material: 100 g of white pine needles were washed with desalted water several times, dried at 80 °C, and ground into powder. The powder was kept at 100 °C for 1 h in a nitrogen atmosphere, and then pyrolyzed at 700 °C for 4 h. The persistent free radical content of the obtained biochar material was 5.83 × 10 19 spins·g -1 The biochar material is ball-milled to a particle size of less than 100 μm for later use.

[0044] (2) Preparation of nanocomposite materials: Tetrabutyl titanate and water were mixed at a mass ratio of 1:15, stirred for 1 hour, and then ultrasonically dispersed for 3 hours. The biochar material prepared in step (1) was added at a mass ratio of 12 times that of tetrabutyl titanate, and ultrasonic dispersion was continued for more than 5 hours to make the system uniformly dispersed. Then vacuum filtration and drying were performed to obtain a precursor; in a nitrogen atmosphere, the temperature was raised to 800°C at a heating rate of 5°C / min, and the precursor was activated at high temperature for 5 hours to obtain the nanocomposite material B.

[0045] [Example 3]

[0046] (1) Preparation of biochar material: 100 g of red pine needles were washed with desalted water for several times, dried at 80 °C, and ground into powder. The powder was kept at 100 °C for 1 h in a nitrogen atmosphere, and then pyrolyzed at 1000 °C for 4 h. The persistent free radical content of the obtained biochar material was 6.81×10 19 spins·g -1 The biochar material is ball-milled to a particle size of less than 100 μm for later use.

[0047] (2) Preparation of nanocomposite materials: Tetrabutyl titanate and water were mixed at a mass ratio of 1:20, stirred for 1 hour, and then ultrasonically dispersed for 1 hour. The biochar material prepared in step (1) was added at a mass ratio of 10 times that of tetrabutyl titanate, and ultrasonication was continued for more than 5 hours to uniformly disperse the system. Then vacuum filtration and drying were performed to obtain a precursor; in a nitrogen atmosphere, the temperature was raised to 700°C at a heating rate of 3°C / min, and the precursor was activated at high temperature for 3 hours to obtain the nanocomposite material C.

[0048] [Comparative Example 1]

[0049] Nanocomposite material D was prepared in a method substantially the same as that of Example 1, except that the biochar material prepared in step (1) was heated to 700° C. at a heating rate of 3° C. / min under a nitrogen atmosphere and activated at high temperature for 3 h to obtain nanocomposite material D.

[0050] [Comparative Example 2]

[0051] Nanocomposite material E was prepared by the same method as in Example 1, except that the pyrolysis conditions in step (1) were adjusted to 600°C for 5 h. The persistent free radical content of the biochar material obtained by EPR was 4.11×10 19 spins·g -1 The biochar material is used to prepare nanocomposite material E according to step (2).

[0052] [Comparative Example 3]

[0053] Nanocomposite material F was prepared by the same method as in Example 1, except that the pyrolysis conditions in step (1) were adjusted to 1200°C for 2 h. The persistent free radical content of the biochar material obtained by EPR was 7.53×10 19 spins·g -1 The biochar material is used to prepare nanocomposite material F according to step (2).

[0054]

ASS salt decolorization experiment

[0055] The nanocomposites provided in Examples 1-3 and Comparative Examples 1-3 were used as decolorizing agents, respectively, and 50 wt % ASS salt solution was decolorized using the following method, and the decolorization effects were recorded in Table 1 for comparative analysis.

[0056] 5 g of the nanocomposite material was weighed and added to the built-in beaker of the ultraviolet catalytic oxidation device, and then 100 g of 50 wt% AAS salt solution was added thereto, and the ultraviolet light was turned on at 100 lux, and the stirring was turned on at 200 r / min, and the decolorization treatment was carried out for 30 minutes. After the end, the nanocomposite material was filtered out, and the AAS salt solution was subjected to real-time colorimetric analysis, as well as colorimetric analysis after storage under sealed conditions for 3 months.

[0057] Table 1. Chromatographic analysis results of AAS salt solution after decolorization

[0058] Real-time Chroma / Hazen Storage 3 months color / Hazen Nanocomposite material A 32 30 Nanocomposite material B 16 18 Nanocomposite C 28 31 Nanocomposite materials D 103 151 Nanocomposite materials E 87 99 Nanocomposite materials F 39 85

[0059] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a nanocomposite material, characterized in that: The following steps are involved: Tetrabutyl titanate and water were mixed and dispersed for 1 to 4 hours to obtain a hydrolyzate; the content of persistent free radicals was 4.52×10 19 spins·g -1 ~6.81×10 19 spins·g -1 The biochar is added to the above hydrolyzate and dispersed for more than 4 hours, preferably 5 to 10 hours; vacuum filtration and drying are performed to obtain a precursor; Under an inert atmosphere, the precursor is activated at high temperature for 2 to 5 hours to obtain the nanocomposite material.

2. The method for preparing the nanocomposite material according to claim 1, characterized in that: The particle size of the biochar is less than 100 μm.

3. The method for preparing the nanocomposite material according to claim 1 or 2, characterized in that: The mass ratio of tetrabutyl titanate to biochar is 1:(8-12).

4. The method for preparing a nanocomposite material according to any one of claims 1 to 3, characterized in that: The mixing mass ratio of tetrabutyl titanate and water is 1:(10-20).

5. The method for preparing a nanocomposite material according to any one of claims 1 to 4, characterized in that: The high temperature activation temperature of the precursor is 500-1000°C, preferably 700-800°C.

6. The method for preparing a nanocomposite material according to any one of claims 1 to 5, characterized in that: The biochar is pine needles, preferably one or more selected from black pine needles, white pine needles, and red pine needles.

7. A nanocomposite material obtained by the method according to any one of claims 1 to 6.

8. Use of the nanocomposite material prepared by the method according to any one of claims 1 to 6 in decolorizing an AAS salt product.

9. A method for decolorizing an AAS salt product, characterized in that: After mixing 50 wt% AAS salt solution and the nanocomposite material according to any one of claims 1 to 6, stirring and treating under ultraviolet irradiation, filtering, and recovering the decolorized AAS salt solution; Preferably, the product chromaticity of the AAS salt solution is greater than 150 Hazen, preferably 180-250 Hazen; Preferably, the mixing mass ratio of the AAS salt solution and the nanocomposite material is 1:(0.01-0.2); Preferably, the illumination intensity of the ultraviolet irradiation is 50 to 200 lux, and the illumination time is 20 to 60 min.