WO2020143128A1

WO2020143128A1 - Silver/titanium dioxide in-situ loaded biomass material based on polydopamine modification and preparation method therefor

Info

Publication number: WO2020143128A1
Application number: PCT/CN2019/083248
Authority: WO
Inventors: 刘贡钢; 朱秀; 薛志成; 胡进波; 尚健雄; 苌姗姗; 张翔; 李贤军; 刘元; 吴志平; 路周
Original assignee: 湖南桃花江竹材科技股份有限公司
Priority date: 2019-01-09
Filing date: 2019-04-18
Publication date: 2020-07-16
Also published as: CN109732725A

Abstract

A silver/titanium dioxide in-situ loaded biomass material based on polydopamine modification and a preparation method therefor. The method comprises the following steps: impregnating a pretreated biomass material in a dopamine solution, adjusting a pH value to be 8-10 and performing stirring reaction to obtain a polydopamine modified biomass material; first impregnating the polydopamine modified biomass material in a titanyl sulfate solution and then performing hydrolysis reaction in an alkaline solution having the pH value of 7-10 to obtain a titanium dioxide in-situ loaded biomass material; impregnating the obtained titanium dioxide in-situ loaded biomass material in a silver nitrate solution, performing reduction reaction, and drying the material to obtain the silver/titanium dioxide in-situ loaded biomass material. The method has the advantages that the method is simple, industrialization is easily implemented, a mildew-proof effect is good, and the like.

Description

Polydopamine-modified in-situ loaded silver/titanium dioxide biomass material and preparation method thereof

【Technical field】

The invention relates to the field of mildew resistance, in particular to a polydopamine modified in situ silver/titanium dioxide-based biomass material and a preparation method thereof.

【Background technique】

Wood bamboo materials, plastics, ceramics and other materials are prone to mildew problems in a humid environment. Especially wood bamboo materials as a biological material contains a large number of nutrients inside, and the wood bamboo materials have a large number of fine pores and voids, air And moisture easily enters it and causes its mildew. Therefore, during storage, transportation and use, especially under the harsh conditions of outdoor sunlight, rain, etc., it is prone to mildew, which affects the use and ornamental performance of the material.

Titanium dioxide photocatalyst has the functions of anti-fouling, self-purification, antibacterial, antibacterial, anti-mildew, etc. It can absorb ultraviolet rays in sunlight, use light energy to generate photo-electron-hole pairs, and the separated holes activate oxygen to form active oxygen, which is effective It destroys the structure of adsorbing mold on the surface, and has improved material color stability and excellent photocatalytic mold resistance. However, the current titanium dioxide loading methods on the market mostly use the method of preparing titanium dioxide and then coating the loading. The photocatalytic active component obtained by this method is often easy to fall off, not firm, and the nanoparticles loaded on the surface of the substrate are uneven And, the method of coating the load often uses higher titanium content but the atom utilization rate is not high. In addition, pure titanium dioxide has a narrow photoresponse range and can only be excited in the near-ultraviolet region to generate photogenerated electron-hole pairs, while ultraviolet light accounts for only about 4% of sunlight, and the utilization of sunlight is low, while Photogenerated electron-hole pairs can easily recombine and affect the photocatalytic effect.

[Invention content]

The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art, and to provide an in situ silver/titania-modified biomass material based on polydopamine modified and easy to achieve industrialization, good anti-mold effect and uniform dispersion of nanoparticles and preparation thereof method.

To solve the above technical problems, the present invention adopts the following technical solutions:

A preparation method of silver/titania-loaded biomass material based on polydopamine modification includes the following steps:

S1. Immerse the pretreated biomass material in a dopamine solution, adjust the pH to 8-10, and perform a stirring reaction to obtain a polydopamine-modified biomass material;

S2. The polydopamine-modified biomass material obtained in step S1 is first immersed in a titanyl sulfate solution to adsorb titanyl sulfate positive ions, adsorbed and saturated, and then filtered, and then placed in an alkaline solution with a pH value of 7-10 for hydrolysis reaction , To obtain biomass material with titanium dioxide loaded in situ;

S3. Immerse the TiO2 biomass material in situ obtained in step S2 in a silver nitrate solution, and use the modified polydopamine amino group to perform a reduction reaction on the silver ions adsorbed on the surface of the biomass material, and dry to obtain in situ loaded silver/ Titanium dioxide biomass material.

As a further improvement to the above technical solution:

In the step S1, the concentration of the dopamine solution is 0.01-2 mg/mL, and the stirring reaction time is 0.5-24 hours.

In the step S1, the stirring reaction further includes ultrasonic, cleaning and drying steps, the ultrasonic time is 1-30 min, and the cleaning uses deionized water cleaning.

Preferably, in the step S1, the drying temperature is 60-100°C.

In the step S1, the pH adjusting agent for adjusting the pH value is Tris buffer or sodium hydroxide solution.

In the step S2, the concentration of the titanyl sulfate solution is 0.001 to 1 mol/L, and the immersion time is 1 to 12 hours.

In the step S2, the alkaline solution is ammonia water or sodium hydroxide, and the hydrolysis reaction time is 0.5 to 2 hours.

Preferably, in the step S2, the temperature of the hydrolysis reaction is 50-90°C.

In the step S2, the hydrolysis reaction further includes washing and drying steps.

In the step S3, the concentration of the silver nitrate solution is 0.001 to 0.1 mol/L, and the reduction reaction time is 0.5 to 2 hours.

The biomass material is wood and/or bamboo.

As a general inventive concept, the present invention also provides a polydopamine-modified in situ silver/titanium dioxide-based biomass material, the surface of the biomass material is modified with a polydopamine membrane, and the outer surface and pores of the biomass material Titanium dioxide nanoparticles and silver nanoparticles are grown in situ on the inner wall.

Compared with the prior art, the advantages of the present invention are:

The in situ silver/titanium dioxide-based biomass material modified by polydopamine of the present invention uses the biomimetic material polydopamine as an intermediate fixation layer, and the silver-doped titanium dioxide is loaded in situ on the outer surface and the inner wall of the pores of the modified polydopamine-modified biomass material Nanoparticles, part of the silver element is uniformly dispersed on the surface of the biomass material, and part of the silver element is deposited on the surface of the nano-titanium dioxide, reducing the band gap of the titanium dioxide, making it absorb in the visible light range, and also reducing the photogenerated electrons of the titanium dioxide -The recombination probability of hole pairs, thereby improving their photocatalytic efficiency under visible light conditions. The protection of polydopamine film, the photocatalytic effect of silver/titanium dioxide nanoparticles and the sterilization function of silver nanoparticles themselves can solve the problem of mildew on the surface of biomass materials. It has multiple anti-mold effects, mainly in three aspects. Mr. Material Surface Modified polydopamine film can block the entry of air and water and improve the anti-mold effect of biomass materials. The photocatalytic effect of silver-doped titanium dioxide nano-photocatalyst can significantly improve its anti-mold effect and has an efficient sterilization function The silver nanoparticles can further enhance its anti-mold effect.

The preparation method of the in-situ silver/titanium dioxide-based biomass material modified by polydopamine according to the present invention utilizes the polymerization reaction of dopamine under mild conditions to perform modification treatment on the surface of the biomass material, and relies on the bionic adhesion characteristics of polydopamine to deposit Modification of the biomass material surface, the use of its highly active functional groups can achieve the solid loading of nanoparticles, and then through the impregnation-in-situ growth method on the modified biomass material outer surface and pore wall in situ loading titanium dioxide and silver Nanoparticles adopt the impregnation-in-situ growth method when loading titanium dioxide and silver nanoparticles. While exerting the effect of nanoparticles to improve the anti-mold effect, the nanoparticles are firmly and evenly dispersed to improve the atom utilization rate and greatly save economic costs. The preparation method and treatment process of the invention have mild conditions and remarkable effects, and can be applied to the field of outdoor substrate applications.

[Description of the drawings]

Figure 1 is a picture of the sample in a closed wet environment for 4 days and 60 days.

FIG. 2 is a comparative photograph of a bamboo material (a) loaded with titanium dioxide in situ in Comparative Example 2 and a bamboo material (b) loaded with silver/titania in situ in Example 1 for 120 days under a closed humid environment.

Figure 3 is a scanning electron micrograph (SEM) of bamboo cross-section and SEM characterization mapping analysis of four elements of C, O, Ti and Ag.

Figure 4 is the SEM and EDS spectrum analysis of the longitudinal surface of the bamboo substrate.

【detailed description】

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Example 1

The preparation method of the in-situ silver/titania-supported biomass material modified by polydopamine in this embodiment includes the following steps:

1) Pre-treat fresh bamboo materials, remove bamboo green and bamboo yellow, wash and dry, to obtain pre-treated bamboo materials;

2) Immerse the pretreated bamboo obtained in step 1) into 125mL of 0.4mg/mL dopamine solution, add Tris buffer to adjust the pH to 8.5, stir at room temperature for 2h, after the reaction is completed, sonicate for 2min and wash with deionized water. Strong dopamine molecule, after drying, get polydopamine modified bamboo.

3) The bamboo material modified with polydopamine obtained in step 2) was immersed in 100mL 0.01mol/L titanyl sulfate solution for 2h, filtered out and put into an aqueous ammonia solution with a pH of 10, and hydrolyzed at 70℃ for 1h. Take out the bamboo material, rinse it and dry it at 60℃ to get the bamboo material loaded with titanium dioxide in situ.

4) Take the bamboo material obtained by in-situ TiO2 in step 3) and immerse it in 100ml of 0.001mol/L silver nitrate solution for 1h, use the amino group on the surface of polydopamine to reduce the silver ion in situ to silver element, take out the bamboo and dry it at 60℃ for 12h, The bamboo material with silver/titanium dioxide loaded in situ can be obtained.

In this embodiment, the biomass material is bamboo, and in other embodiments, the same or similar technical effects of wood can also be adopted.

The impregnation solution of titanyl sulfate and silver nitrate used in this embodiment has a low concentration and can be recycled.

In this embodiment, the temperature of the hydrolysis reaction is 70°C, which is helpful for accelerating the progress of the hydrolysis reaction. In other embodiments, the hydrolysis reaction can also be performed at normal temperature.

Comparative Example 1

In this comparative example, the titanium dioxide-loaded bamboo material is prepared by a conventional sol-gel method, and the preparation steps include the following steps:

2) Mix deionized water with hydrochloric acid at room temperature and stir well to obtain 40 mL of 0.1mol/L hydrochloric acid aqueous solution. During the stirring, a mixed solution of 20 mL of butyl titanate and 40 mL of absolute ethanol was slowly added dropwise to the aqueous hydrochloric acid solution. After the dropwise addition, stirring was continued to obtain a translucent titanium dioxide sol.

3) The pretreated bamboo material obtained in step 1) is immersed in the prepared titanium dioxide sol and is pulled, and the pulled bamboo material is dried at 60°C to obtain a bamboo material loaded with titanium dioxide.

Comparative Example 2

In this comparative example, a bamboo material prepared by in-situ growth method using a dipping-in-situ growth method has the following steps:

3) The polydopamine-modified bamboo obtained in step 2) was immersed in 100 mL of 0.01 mol/L titanyl sulfate solution for 2 hours, taken out and placed in an aqueous ammonia solution with a pH of 10, and the bamboo was hydrolyzed at 70°C for 1 hour. Take it out, rinse it and dry it at 60 ℃ to get bamboo with titanium dioxide loaded in situ.

Comparative Example 3

A bamboo material prepared in situ by using the dipping-in-situ growth method of the present comparative example comprises the following steps:

3) Take the polydopamine-modified bamboo material obtained in step 2) and immerse it in 100ml of 0.001mol/L silver nitrate solution for 1 hour. Use the amino groups on the surface of the polydopamine to reduce the silver ions in situ to the silver element. Take out the bamboo material and dry it at 60℃ for 12h. Bamboo with silver in situ.

Raw bamboo (that is, fresh bamboo), polydopamine-modified bamboo in Example 1, titanium dioxide-loaded bamboo in Comparative Example 1, titanium dioxide-loaded bamboo in-situ in Comparative Example 2, and silver-loaded bamboo in-situ in Comparative Example 3 1. The in situ silver/titanium dioxide-loaded bamboo materials of Example 1 were placed outdoors in a light-transmissive enclosed humid environment to simulate mild conditions for mold initiation test, and observe and record the time and degree of mold initiation of different bamboo samples.

The results showed that on the second day after leaving, the original bamboo began to mold, and other samples did not have mold; after the fourth day, the original bamboo had a lot of mold, the dopamine treated bamboo began to mold, and the other samples had no mold; after the sixth day, Raw bamboo and polydopamine-modified bamboo in Example 1 had a lot of mold, and the bamboo in situ loaded with silver in Comparative Example 3 also started to have mold, and other samples showed no mold. After 8 days, the bamboo with titanium dioxide loaded in Comparative Example 1 had A small amount of black mold appeared; after day 60, the bamboo material loaded with titanium dioxide in situ in Comparative Example 2 and the bamboo material loaded with silver/titanium dioxide in situ in Example 1 still showed no obvious mold. The photos of mildew on Day 4 and Day 60 are shown in Figure 1, where Figure 1a is the photo on the 4th day after placement, and Figure 1b is the photo on the 60th day after placement, 0, 1, 2, and 3 in the figure. , 4, and 5 respectively represent raw bamboo, polydopamine-modified bamboo in Example 1, bamboo with titanium dioxide loaded in Comparative Example 1, bamboo with titanium dioxide in-situ loaded in Comparative Example 2, bamboo with silver in-situ loaded in Comparative Example 3, Examples 1 Bamboo material with silver/titanium dioxide loaded in situ.

FIG. 2 is a comparison of photos after 120 days of mold initiation test of bamboo material (a) loaded with titanium dioxide in situ in Comparative Example 2 and bamboo material (b) loaded in situ with silver/titania in Example 1, and found that bamboo material loaded with titanium dioxide in situ in Comparative Example 2 There is a small amount of white mold on the surface, and the bamboo material with silver/titanium dioxide loaded in situ in Example 1 has not found mold. It can be seen that polydopamine, silver loading and titanium dioxide loading can delay the mold initiation time to improve the mildew resistance of bamboo, while the impregnation-in-situ growth method loading titanium dioxide and loading silver/titanium dioxide can significantly improve the bamboo mildew resistance. The silver/titanium dioxide bamboo has the best mildew resistance.

3 is a scanning electron microscope image and a mapping analysis diagram of a cross-section of a bamboo material with silver/titanium dioxide loaded in situ in Example 1, wherein FIGS. 3a and 3f are scanning electron microscope images, and FIGS. 3b, 3c, 3d, and 3e are C, O, and 3, respectively. The SEM characterization mapping analysis of the four elements Ti and Ag shows from Figure 3 that silver and titanium elements are evenly distributed on the surface of the substrate, and a large number of nanoparticles are distributed on the inner wall of the bamboo pores.

Figure 4 is the SEM and EDS spectrum analysis of the longitudinal surface of the bamboo loaded with silver/titanium dioxide in Example 1. It can be seen from the figure that a large number of silver and titanium dioxide nanoparticles are evenly dispersed on the longitudinal surface of the bamboo, and the EDS spectrum can be seen The silver element is deposited on the surface of titanium dioxide nanoparticles to achieve silver doping of titanium dioxide.

Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can use the technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or to modify the equivalent implementation of equivalent changes example. Therefore, any simple modifications, equivalent changes, and modifications to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention should fall within the protection scope of the technical solution of the present invention.

Claims

A preparation method of in-situ silver/titanium dioxide-based biomass material modified by polydopamine is characterized in that it includes the following steps:

S1. Immerse the pretreated biomass material in a dopamine solution, adjust the pH to 8-10, and perform a stirring reaction to obtain a polydopamine-modified biomass material;

S2. The polydopamine-modified biomass material obtained in step S1 is first immersed in a titanyl sulfate solution to adsorb titanyl sulfate positive ions, adsorbed and saturated, and then filtered, and then placed in an alkaline solution with a pH value of 7-10 for hydrolysis reaction , To obtain biomass material with titanium dioxide loaded in situ;

S3. Immerse the TiO2 biomass material in situ obtained in step S2 in a silver nitrate solution, and use the modified polydopamine amino group to perform a reduction reaction on the silver ions adsorbed on the surface of the biomass material, and dry to obtain in situ loaded silver/ Titanium dioxide biomass material.
The preparation method according to claim 1, wherein in the step S1, the concentration of the dopamine solution is 0.01-2 mg/mL, and the stirring reaction time is 0.5-24 hours.
The preparation method according to claim 2, characterized in that in step S1, the stirring reaction further includes ultrasonic, cleaning, and drying steps, the ultrasonic time is 1 to 30 minutes, and the cleaning uses deionized water Clean.
The preparation method according to claim 3, wherein in step S1, the pH adjusting agent for adjusting the pH value is Tris buffer or sodium hydroxide solution.
The preparation method according to any one of claims 1 to 4, wherein in step S2, the concentration of the titanyl sulfate solution is 0.001 to 1 mol/L, and the immersion time is 1 to 12 h .
The preparation method according to claim 5, wherein in the step S2, the alkaline solution is ammonia water or sodium hydroxide, and the hydrolysis reaction time is 0.5 to 2 hours.
The preparation method according to claim 6, wherein in the step S2, the hydrolysis reaction further includes washing and drying steps.
The preparation method according to any one of claims 1 to 4, wherein in step S3, the concentration of the silver nitrate solution is 0.001 to 0.1 mol/L, and the reduction reaction time is 0.5 to 2h.
The preparation method according to any one of claims 1 to 4, wherein the biomass material is wood and/or bamboo.
A polydopamine-modified in situ silver/titanium dioxide-based biomass material, characterized in that: the surface of the biomass material is modified with a polydopamine film, and titanium dioxide is grown in situ on both the outer surface of the biomass material and the inner wall of the pores Nanoparticles and silver nanoparticles.