阅读说明：本技术 一种应用于光催化和物理吸附领域的纤维素/氧化石墨烯/二氧化钛水凝胶及其制备方法 (Cellulose/graphene oxide/titanium dioxide hydrogel applied to fields of photocatalysis and physical adsorption and preparation method thereof ) 是由 祁海松 陈怡安 刘德桃 吕发创 于 2019-11-25 设计创作，主要内容包括：本发明公开了一种应用于光催化和物理吸附领域的纤维素/氧化石墨烯/二氧化钛水凝胶材料及其制备方法。该制备方法包括：制备氢氧化钠/尿素水溶液进行预冷处理,然后加入纤维素搅拌得到纤维素溶液；制备氧化石墨烯和二氧化钛混合水溶液加入到纤维素溶液中,流延成膜得到纤维素/氧化石墨烯/二氧化钛水凝胶。本发明提供的水凝胶可以同时进行化学光催化反应和物理吸附,大大提高污水处理能力。本发明提供的制备方法,具有对设备要求不高,可大规模生产,绿色无污染,操作简单等优点。本发明提供的水凝胶材料能够应用于光催化和物理吸附领域。(The invention discloses a cellulose/graphene oxide/titanium dioxide hydrogel material applied to the fields of photocatalysis and physical adsorption and a preparation method thereof. The preparation method comprises the following steps: preparing a sodium hydroxide/urea aqueous solution, carrying out pre-cooling treatment, adding cellulose, and stirring to obtain a cellulose solution; preparing a mixed aqueous solution of graphene oxide and titanium dioxide, adding the mixed aqueous solution into a cellulose solution, and performing tape casting to form a film so as to obtain the cellulose/graphene oxide/titanium dioxide hydrogel. The hydrogel provided by the invention can simultaneously carry out chemical photocatalytic reaction and physical adsorption, and greatly improves the sewage treatment capacity. The preparation method provided by the invention has the advantages of low requirement on equipment, capability of large-scale production, no pollution, simplicity in operation and the like. The hydrogel material provided by the invention can be applied to the fields of photocatalysis and physical adsorption.)

1. A preparation method of cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption is characterized by comprising the following steps:

(1) adding sodium hydroxide and urea into water, uniformly mixing to obtain a solution of sodium hydroxide and urea, then carrying out precooling treatment to obtain a precooled solution, adding cellulose into the precooled solution, and uniformly stirring to obtain a cellulose solution;

(2) adding graphene oxide and titanium dioxide into water, uniformly mixing to obtain a graphene oxide/titanium dioxide mixed solution, then mixing the cellulose solution obtained in the step (1) with the graphene oxide/titanium dioxide mixed solution, and uniformly stirring to obtain a cellulose/graphene oxide/titanium dioxide aqueous solution;

(3) and (3) casting the cellulose/graphene oxide/titanium dioxide aqueous solution obtained in the step (2) into a film, then soaking the film in a dilute sulfuric acid solution for coagulation bath treatment to obtain hydrogel, and washing to obtain the cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption.

2. The method for preparing cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption according to claim 1, wherein the mass ratio of sodium hydroxide to urea in the step (1) is 6: 14-8: 10.

3. the method for preparing cellulose/graphene oxide/titanium dioxide hydrogel for application in the fields of photocatalysis and physical adsorption according to claim 1, wherein the mass ratio of the urea to the water in the step (1) is 10: 82-14: 80.

4. the preparation method of the cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption according to claim 1, wherein the mass of the cellulose in the step (1) is 2-8% of the mass of the pre-cooled solution.

5. The preparation method of the cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption according to claim 1, wherein the temperature of the precooling treatment in the step (1) is-20 ℃ to-12 ℃; the time of the pre-cooling treatment is 1-2 hours.

6. The method for preparing cellulose/graphene oxide/titanium dioxide hydrogel for application in the fields of photocatalysis and physical adsorption according to claim 1, wherein the mass ratio of the graphene oxide in the step (2) to the cellulose in the step (1) is 2: 98-8: 92; the mass ratio of the titanium dioxide in the step (2) to the cellulose in the step (1) is 20: 80-30: 70.

7. the method for preparing the cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption according to claim 1, wherein in the graphene oxide/titanium dioxide mixed solution in the step (2), the concentration of graphene oxide is 0.2% -2%, the concentration of titanium dioxide is 2% -8%, and the volume of the graphene oxide/titanium dioxide mixed solution in the step (2) is 10% -30% of the volume of the cellulose solution.

8. The preparation method of the cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption according to claim 1, wherein the mass percentage concentration of the dilute sulfuric acid solution in the step (3) is 4-6%.

9. The method for preparing cellulose/graphene oxide/titanium dioxide hydrogel for application in the fields of photocatalysis and physical adsorption according to claim 1, wherein the coagulation bath treatment time in the step (3) is 5-10 minutes.

10. A cellulose/graphene oxide/titanium dioxide hydrogel for application in the fields of photocatalysis and physical adsorption, prepared by the preparation method of any one of claims 1 to 9.

Technical Field

The invention belongs to the fields of photocatalysis and physical adsorption, and particularly relates to a cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption and a preparation method thereof.

Background

Nowadays, dye waste water is mainly from textile, leather, paper, rubber, plastics, cosmetics, pharmaceutical and food industries. Since dye wastewater is always discharged in large quantities, has a complicated composition, is dark in color, and has high toxicity, it causes serious pollution and harm to the natural environment and human health if it is not properly treated before being discharged into natural water. The current treatment methods for dye wastewater include physical, chemical and biological methods, etc. These processes can treat industrial dye wastewater by physical adsorption, chemical catalytic degradation, liquid membrane separation, electrolysis, biological treatment, oxidation and other processes. However, the effectiveness, cost, and environmental impact of these processes vary. Of these processes, the physisorption process and the chemical catalytic degradation process are more competitive than others because they are readily available, less costly and have a wider range of applications. For example, a composite material which uses biological cellulose fiber as a matrix and uses titanium dioxide-loaded graphene oxide as a filler has been reported to remove methyl blue in dye wastewater with high efficiency, but the problems of repeated use and further reduction of the residual rate of the dye wastewater are not solved (Liu, L. -P.; Yang, X. -N.; Ye L.; Xue, D. -D.; L.; L.L. -; L.iu, M.; Jia, S.-R.;Hou, Y.; Chu, L.-Q.; Zhong, C., Preparation and characterization of aphotocatalytic antibacterial material: Graphene oxide/TiO₂/bacterialcellulose nanocomposite. Carbohydrate polymers 2017, 174, 1078-1086.）。

Disclosure of Invention

In order to make up for the defects in the prior art, the invention aims to provide a cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption and a preparation method thereof.

The invention provides a preparation method of cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption, which comprises the following steps: cellulose is taken as a base material, and titanium dioxide and graphene oxide are compounded to prepare cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption; the hydrogel is convenient to take out and put into a reaction system, and does not bring secondary pollution; the process for preparing the cellulose/graphene oxide/titanium dioxide hydrogel has the advantages of few dependent equipment, greenness, no pollution, large-scale production, simplicity in operation and the like.

The invention provides a preparation method of cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption, which comprises the following steps:

(1) adding sodium hydroxide and urea into deionized water, uniformly mixing to obtain an aqueous solution of the sodium hydroxide and the urea, then placing the aqueous solution of the sodium hydroxide and the urea in a refrigerator for precooling to obtain a precooled solution, adding cellulose into the precooled solution, and mechanically and uniformly stirring to obtain a cellulose solution;

(2) adding graphene oxide and titanium dioxide into deionized water, uniformly mixing (mechanically stirring) to obtain a graphene oxide/titanium dioxide mixed solution, then mixing the cellulose solution obtained in the step (1) with the graphene oxide/titanium dioxide mixed solution, and mechanically stirring uniformly to obtain a cellulose/graphene oxide/titanium dioxide aqueous solution;

(3) and (3) casting the cellulose/graphene oxide/titanium dioxide aqueous solution obtained in the step (2) on a glass plate to form a film, then soaking the film in a dilute sulfuric acid solution for coagulation bath treatment to obtain hydrogel after coagulation, and washing the hydrogel for multiple times by using deionized water to obtain the cellulose/graphene oxide/titanium dioxide hydrogel applied to the fields of photocatalysis and physical adsorption.

Further, the mass ratio of the sodium hydroxide to the urea in the step (1) is 6: 14-8: 10.

further, the mass ratio of the sodium hydroxide to the water in the step (1) is 6: 82-8: 80.

further, the time for dissolving and stirring the cellulose in the step (1) is 5-8 minutes.

Further, the mass ratio of the urea to the water in the step (1) is 10: 82-14: 80.

further, the mass of the cellulose in the step (1) is 2% -8% of the mass of the pre-cooled solution.

Further, the temperature of the precooling treatment in the step (1) is-20 to-12 ℃; the time of the pre-cooling treatment is 1-2 hours.

Preferably, the temperature of the precooling treatment in the step (1) is-18 ℃ to-12 ℃.

Further, the mass ratio of the graphene oxide in the step (2) to the cellulose in the step (1) is 2: 98-8: 92; the mass ratio of the titanium dioxide in the step (2) to the cellulose in the step (1) is 20: 80-30: 70.

further, the volume of the graphene oxide/titanium dioxide mixed solution in the step (2) is 10-30% of the volume of the cellulose solution.

Further, in the mixed solution of graphene oxide and titanium dioxide in the step (2), the concentration of graphene oxide is 0.2% -2%, and the concentration of titanium dioxide is 2% -8%.

Further, the mass percentage concentration of the dilute sulfuric acid solution in the step (3) is 4-6%.

Further, the coagulation bath treatment time in the step (3) is 5-10 minutes.

Preferably, the coagulation bath treatment time is 5 to 8 minutes.

The invention provides a cellulose/graphene oxide/titanium dioxide hydrogel prepared by the preparation method and applied to the fields of photocatalysis and physical adsorption.

The titanium dioxide nano composite material based on the cellulose combines the advantages of the green carrier and the photocatalytic performance of the titanium dioxide, and simultaneously loads the graphene oxide, so that on one hand, the dye molecule adsorption capacity of the green carrier can be improved, and on the other hand, the photodegradation capacity of the green carrier can be improved by cooperating with the titanium dioxide. Furthermore, the cellulose/graphene oxide/titanium dioxide hydrogel material has excellent physical adsorption and chemical degradation capabilities, and can be further used as a photocatalytic carrier to be applied to multiple fields such as physical adsorption and photodegradation.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the raw material cellulose used by the preparation method provided by the invention is a natural polymer material with abundant resources in nature, and has low price and wide source; and the preparation process does not involve chemical reaction basically, and the preparation method has the advantages of low dependence on equipment, simple operation, large-scale production, simple and convenient process flow and the like.

(2) The cellulose-based hydrogel carrier prepared by the invention can simultaneously physically adsorb dye molecules and chemically degrade the dye molecules, and can greatly improve the dye sewage treatment capability. Meanwhile, the hydrogel material does not introduce secondary pollution, and is convenient to put in and take out a reaction system.

Detailed Description

The following examples are presented to further illustrate the practice of the invention, but the practice and protection of the invention is not limited thereto. It is noted that the processes described below, if not specifically described in detail, are all realizable or understandable by those skilled in the art with reference to the prior art. The reagents or apparatus used are not indicated to the manufacturer, and are considered to be conventional products available by commercial purchase.