阅读说明：本技术 一种Ag/AgBr石墨烯复合凝胶的制备方法 (Preparation method of Ag/AgBr graphene composite gel ) 是由 蔡小丹 于 2020-12-07 设计创作，主要内容包括：本发明公开了一种Ag/AgBr石墨烯复合凝胶的制备方法,包括下述步骤：首先将氧化石墨烯和硫酸与磷酸混合得到磷硫共掺杂氧化石墨烯,之后将其与NaHSO-3反应制备得到石墨烯凝胶,最后将复合凝胶与硝酸银、十六烷基三甲基溴化铵(CTAB)反应得到Ag/AgBr石墨烯复合凝胶。所述方法成本低、操作简单、高效节能,得到的复合凝胶应用于降解染料污水中的罗丹明B。(The invention discloses a preparation method of Ag/AgBr graphene composite gel, which comprises the following steps: firstly, mixing graphene oxide, sulfuric acid and phosphoric acid to obtain phosphorus-sulfur co-doped graphene oxide, and then mixing the phosphorus-sulfur co-doped graphene oxide with NaHSO 3 The graphene gel is prepared by reactionAnd finally, reacting the composite gel with silver nitrate and Cetyl Trimethyl Ammonium Bromide (CTAB) to obtain the Ag/AgBr graphene composite gel. The method is low in cost, simple to operate, efficient and energy-saving, and the obtained composite gel is applied to degrading rhodamine B in dye sewage.)

1. The preparation method of the Ag/AgBr graphene composite gel is characterized by comprising the following steps:

(1) adding graphene oxide into 100ml of deionized water, performing ultrasonic dispersion for 1 hour, adding phosphoric acid, performing ultrasonic treatment for 4 hours until the mixture is uniformly mixed, drying a sample at 85 ℃ for 4 hours, transferring the sample into a muffle furnace, and performing high-temperature calcination;

(2) adding the product obtained in the step (1) into 100ml of deionized water, performing ultrasonic dispersion for 1h, adding sulfuric acid, performing ultrasonic dispersion for 2h until the mixture is uniformly mixed, performing freeze drying, and then performing high-temperature calcination;

(3) dispersing the product of the step (2) in 100ml of deionized water, carrying out ultrasonic treatment for 1h, and then adding NaHSO₃Standing at 70 deg.C for 12h, and dialyzing with deionized water for 24 h;

(4) mixing AgNO₃Dissolving in 20ml deionized water, soaking the product of step (3) in cetyl trimethyl ammonium bromide solution, standing at 60 deg.C for 6 hr, cooling to room temperature, washing with deionized water and ethanol, and soaking in AgNO₃And (4) putting the solution for 12h, finally washing the solution by using deionized water and ethanol, and freeze-drying the solution to obtain the Ag/AgBr graphene composite gel.

2. The preparation method of the Ag/AgBr graphene composite gel according to claim 1, wherein the mass-to-volume ratio of the graphene to the phosphoric acid in the step (1) is 1 mg: (1-2) μ l.

3. The method for preparing Ag/AgBr graphene composite gel according to claim 1, wherein the calcination temperature in the step (1) is 700-.

4. The preparation method of the Ag/AgBr graphene composite gel according to claim 1, wherein the mass-to-volume ratio of the product of the step (1) to the sulfuric acid in the step (2) is 1 mg: (1-2) μ l.

5. The method for preparing Ag/AgBr graphene composite gel according to claim 1, wherein the calcination temperature in the step (2) is 800-.

6. The preparation method of Ag/AgBr graphene composite gel according to claim 1, wherein in the step (3), the product of the step (2) is mixed with NaHSO₃The mass ratio of (A) to (B) is 1 mg: (4-6) mg.

7. The preparation method of Ag/AgBr graphene composite gel according to claim 1, wherein in the step (4), the product of the step (3) and AgNO are mixed₃And the mass ratio of the hexadecyl trimethyl ammonium bromide is 1 mg: (1-2) mg: (4-6) mg.

8. The preparation method of Ag/AgBr graphene composite gel according to claims 1 to 7, wherein the composite gel prepared by the preparation method of the composite graphene gel is applied to photocatalytic degradation of rhodamine B in dye wastewater.

Technical Field

The invention is applied to photocatalytic degradation of rhodamine B in dye sewage, and particularly relates to a preparation method of Ag/AgBr graphene composite gel.

Background

In our daily life, dyes have wide application in the fields of textile and clothing industry, paper industry, food processing industry and the like. Therefore, the dye wastewater also becomes a large pollution source influencing the life and health of people. Among the dyes, rhodamine b (rhb) is a fluorescent dye that is synthesized by man and is basic. It is applied to various fields of paper making industry, cosmetic industry, mining industry, medicine and the like, and is also a typical industrial dye wastewater pollutant because of strong stability, bright color and low price. The quinoid structure in the molecular chain is the main functional group for the color development of rhodamine B, and the structure is damaged when the quinoid structure is degraded. Currently, silver/silver halide (Ag/AgX, X ═ Cl, Br) has been widely used as a photocatalyst in the process of photodegradation of contaminants, based on the relatively small energy band width of silver/silver halide. In fact, Br has a lower electron affinity relative to Cl, so Ag/AgBr shows higher catalytic activity. However, the problem of easy agglomeration of silver/silver bromide particles still exists so far. In recent years, graphene has attracted much attention due to its attractive physical properties and wide applications. Graphene is a two-dimensional hexagonal lattice-like crystal formed by sp2 hybridization of carbon atoms, and its thickness is only a single atomic layer. Due to the unique electronic structural characteristics and the large specific surface area of the graphene, the graphene has unique advantages in photocatalytic degradation of organic dyes. However, due to easy stacking and poor water solubility of reduced graphene, researchers have rarely studied graphene-based photocatalytic materials. The surface of the graphene oxide is rich in a large number of oxygen-containing functional groups, such as hydroxyl, carboxyl, epoxy and the like, and the oxygen-containing functional groups effectively improve the solubility of the graphene oxide in a polar solvent. In view of the above, it is necessary to develop and prepare such composite materials as rGO/Ag/AgX, but the structure of pure graphene is very stable, there are few "loading sites" capable of providing the loaded metal nanoparticles, and the metal nanoparticles can be agglomerated and exfoliated during the catalytic process, thereby causing the performance of the catalyst itself to be reduced. Therefore, a great deal of research is beginning to use a chemical doping method to modify the surface structure of graphene, so as to improve the catalytic performance of the catalyst.

Disclosure of Invention

The invention aims to provide a preparation method of Ag/AgBr graphene composite gel, which comprises the following raw materials: graphene oxide, phosphoric acid, sulfuric acid, sodium sulfite, hexadecyl trimethyl ammonium bromide and silver nitrate, and the preparation method comprises the following steps:

(1) adding graphene oxide into 100ml of deionized water, performing ultrasonic dispersion for 1 hour, adding phosphoric acid, performing ultrasonic treatment for 4 hours until the mixture is uniformly mixed, drying a sample at 85 ℃ for 4 hours, transferring the sample into a muffle furnace, and performing high-temperature calcination;

(2) adding the product obtained in the step (1) into 100ml of deionized water, performing ultrasonic dispersion for 1h, adding sulfuric acid, performing ultrasonic dispersion for 2h until the mixture is uniformly mixed, performing freeze drying, and then performing high-temperature calcination;

(3) dispersing the product of the step (2) in 100ml of deionized water, carrying out ultrasonic treatment for 1h, and then adding NaHSO₃Standing at 70 deg.C for 12h, and dialyzing with deionized water for 24 h;

(4) mixing AgNO₃Dissolving in 20ml deionized water, soaking the product of step (3) in cetyl trimethyl ammonium bromide solution, standing at 60 deg.C for 6 hr, cooling to room temperature, washing with deionized water and ethanol, and soaking in AgNO₃And (4) putting the solution for 12h, finally washing the solution by using deionized water and ethanol, and freeze-drying the solution to obtain the Ag/AgBr graphene composite gel.

Preferably, the mass-to-volume ratio of the graphene to the phosphoric acid in the step (1) is 1 mg: (1-2) μ l.

Preferably, the calcination temperature in the step (1) is 700-900 ℃, and the calcination time is 2-4 h.

Preferably, the mass-to-volume ratio of the product of step (1) and sulfuric acid in step (2) is 1 mg: (1-2) μ l.

Preferably, the calcination temperature in the step (2) is 800-1200 ℃, and the calcination time is 1-3 h.

Preferably, in the step (3), the product of the step (2) is mixed with NaHSO₃The mass ratio of (A) to (B) is 1 mg: (4-6) mg.

Preferably, in the step (4), the product of the step (3) is mixed with AgNO₃And the mass ratio of the hexadecyl trimethyl ammonium bromide is 1 mg: (1-2) mg: (4-6) mg.

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

(1) the invention provides a preparation method of Ag/AgBr graphene composite gel, the process is very simple, the obtained Ag/AgBr graphene composite gel has excellent photocatalytic performance, silver/silver bromide particles are easy to agglomerate, and the Ag/AgBr particles are loaded on the surface of reduced graphene with a large specific surface area, so that the micronization and good dispersibility of metal particles are realized, the agglomeration of Ag/AgX is avoided, and the photocatalytic performance of the material is improved.

(2) The graphene is prepared into gel, so that the defect that the traditional material cannot be recycled can be overcome, and the graphene can be recycled.

(3) The surface structure of the graphene is improved by doping P, S elements, so that a large number of defect sites are generated on the surface of the graphene, and the graphene can better load Ag/AgBr.

(4) The invention has simple raw materials, is easy to obtain and is environment-friendly.

Drawings

FIG. 1 is a Scanning Electron Microscope (SEM) image of Ag/AgBr graphene composite gel prepared in example 1 of the invention

FIG. 2 is a graph showing the relationship between the removal rate of the product obtained in comparative examples 1-3 to rhodamine B in wastewater and time for the Ag/AgBr graphene composite gel prepared in example 1 of the present invention (1: example 1; 2: comparative example 1; 3: comparative example 2).

Fig. 3 is a curve of the reaction times and the removal rate of the Ag/AgBr graphene composite gel prepared in example 1 of the present invention for continuously degrading rhodamine B in sewage for 5 times.

Detailed description of the preferred embodiments

Example 1:

a preparation method of Ag/AgBr graphene composite gel specifically comprises the following preparation steps:

(1) adding 100mg of graphene oxide into 100ml of deionized water, performing ultrasonic dispersion for 1h, adding 150 mu l of phosphoric acid, performing ultrasonic treatment for 4h until the mixture is uniformly mixed, drying a sample at 85 ℃ for 4h, transferring the sample into a muffle furnace, and calcining the sample at 800 ℃ for 3 h;

(2) adding 100mg of the product obtained in the step (1) into 100ml of deionized water, performing ultrasonic dispersion for 1h, adding 150 mu l of sulfuric acid, performing ultrasonic treatment for 2h until the mixture is uniformly mixed, performing freeze drying, and then calcining for 2h at 1000 ℃;

(3) dispersing 50mg of the product of step (2) in 100ml of deionized water, sonicating for 1h, and then adding 250mg of NaHSO₃Standing at 70 deg.C for 12h, and dialyzing with deionized water for 24 h;

(4) 75mg of AgNO₃Dissolving in 20ml deionized water, soaking 50mg of the product of step (3) in 15ml solution containing 250mg of cetyltrimethylammonium bromide, standing at 60 deg.C for 6h, cooling to room temperature, washing with deionized water and ethanol, and soaking in AgNO₃And (4) putting the solution for 12h, finally washing the solution by using deionized water and ethanol, and freeze-drying the solution to obtain the Ag/AgBr graphene composite gel.

Example 2:

a preparation method of Ag/AgBr graphene composite gel specifically comprises the following preparation steps:

(1) adding 100mg of graphene oxide into 100ml of deionized water, performing ultrasonic dispersion for 1 hour, adding 100 mu l of phosphoric acid, performing ultrasonic treatment for 4 hours until the mixture is uniformly mixed, drying a sample at 85 ℃ for 4 hours, transferring the sample into a muffle furnace, and calcining the sample at 700 ℃ for 2 hours;

(2) adding 100mg of the product obtained in the step (1) into 100ml of deionized water, performing ultrasonic dispersion for 1h, adding 100 mu l of sulfuric acid, performing ultrasonic treatment for 2h until the mixture is uniformly mixed, performing freeze drying, and then calcining for 1h at 800 ℃;

(3) dispersing 50mg of the product of step (2) in 100ml of deionized water, sonicating for 1h, and then adding 200mg of NaHSO₃Standing at 70 deg.C for 12h, and dialyzing with deionized water for 24 h;

(4) 50mg of AgNO₃Dissolving in 20ml deionized water, soaking 50mg of the product of step (3) in 15ml solution containing 200mg of cetyltrimethylammonium bromide, standing at 60 deg.C for 6h, cooling to room temperature, washing with deionized water and ethanol, and soaking in AgNO₃And (4) putting the solution for 12h, finally washing the solution by using deionized water and ethanol, and freeze-drying the solution to obtain the Ag/AgBr graphene composite gel.

Example 3:

a preparation method of Ag/AgBr graphene composite gel specifically comprises the following preparation steps:

(1) adding 100mg of graphene oxide into 100ml of deionized water, performing ultrasonic dispersion for 1h, adding 200 mu l of phosphoric acid, performing ultrasonic treatment for 4h until the mixture is uniformly mixed, drying a sample at 85 ℃ for 4h, transferring the sample into a muffle furnace, and calcining the sample at 900 ℃ for 4 h;

(2) adding 100mg of the product obtained in the step (1) into 100ml of deionized water, performing ultrasonic dispersion for 1h, adding 200 mu l of sulfuric acid, performing ultrasonic treatment for 2h until the mixture is uniformly mixed, performing freeze drying, and then calcining for 3h at 1200 ℃;

(3) dispersing 50mg of the product of step (2) in 100ml of deionized water, sonicating for 1h, and then adding 300mg of NaHSO₃Standing at 70 deg.C for 12h, and dialyzing with deionized water for 24 h;

(4) 100mg of AgNO₃Dissolving in 20ml deionized water, soaking 50mg of the product of step (3) in 15ml solution containing 300mg of cetyltrimethylammonium bromide, standing at 60 deg.C for 6h, cooling to room temperature, washing with deionized water and ethanol, and soaking in AgNO₃And (4) putting the solution for 12h, finally washing the solution by using deionized water and ethanol, and freeze-drying the solution to obtain the Ag/AgBr graphene composite gel.

Example 4:

a preparation method of Ag/AgBr graphene composite gel specifically comprises the following preparation steps:

(1) adding 100mg of graphene oxide into 100ml of deionized water, performing ultrasonic dispersion for 1h, adding 150 mu l of phosphoric acid, performing ultrasonic treatment for 4h until the mixture is uniformly mixed, drying a sample at 85 ℃ for 4h, transferring the sample into a muffle furnace, and calcining the sample at 800 ℃ for 3 h;

(2) adding 100mg of the product obtained in the step (1) into 100ml of deionized water, performing ultrasonic dispersion for 1h, adding 150 mu l of sulfuric acid, performing ultrasonic treatment for 2h until the mixture is uniformly mixed, performing freeze drying, and then calcining for 2h at 1000 ℃;

(3) dispersing 50mg of the product of step (2) in 100ml of deionized water, sonicating for 1h, and then adding 200mg of NaHSO₃Standing at 70 deg.C for 12h, and dialyzing with deionized water for 24 h;

(4) 100mg of AgNO₃Dissolving in 20ml deionized water, soaking 50mg of the product of step (3) in 15ml solution containing 200mg of cetyltrimethylammonium bromide, standing at 60 deg.C for 6h, cooling to room temperature, washing with deionized water and ethanolThen immersing it in AgNO₃And (4) putting the solution for 12h, finally washing the solution by using deionized water and ethanol, and freeze-drying the solution to obtain the Ag/AgBr graphene composite gel.

Comparative example 1:

a preparation method of composite graphene gel specifically comprises the following preparation steps:

(1) dispersing 50mg of graphene oxide in 100ml of deionized water, carrying out ultrasonic treatment for 1h, and then adding 250mg of NaHSO₃Standing at 70 deg.C for 12h, and dialyzing with deionized water for 24 h;

(2) 40mg of AgNO₃Dissolving in 20ml deionized water, soaking 50mg of the product of the step (1) in cetyl trimethyl ammonium bromide solution, standing at 60 deg.C for 6h, cooling to room temperature, washing with deionized water and ethanol, and soaking in AgNO₃And (4) putting the solution for 12h, finally washing the solution by using deionized water and ethanol, and freeze-drying the solution to obtain the graphene composite gel.

Comparative example 2:

a preparation method of composite graphene gel specifically comprises the following preparation steps:

(1) adding 100mg of graphene oxide into 100ml of deionized water, performing ultrasonic dispersion for 1h, adding 150 mu l of phosphoric acid, performing ultrasonic treatment for 4h until the mixture is uniformly mixed, drying a sample at 85 ℃ for 4h, transferring the sample into a muffle furnace, and calcining the sample at 800 ℃ for 3 h;

(2) adding 100mg of the product obtained in the step (1) into 100ml of deionized water, performing ultrasonic dispersion for 1h, adding 150 mu l of sulfuric acid, performing ultrasonic treatment for 2h until the mixture is uniformly mixed, performing freeze drying, and then calcining for 2h at 1000 ℃;

(3) dispersing 50mg of the product of step (2) in 100ml of deionized water, sonicating for 1h, and then adding 200mg of NaHSO₃Standing at 70 deg.C for 12h, and dialyzing with deionized water for 24 h; freeze drying to obtain composite graphene gel

And (3) performance testing:

in the invention, rhodamine B solution is selected as a sample. 50mg of the materials prepared in example 1 and comparative examples 1-2 were placed in 100ml beakers, 100ml of 10mM/L rhodamine B solution was added, and after irradiating the mixture with ultraviolet light under continuous stirring, 5ml of the sample was taken out every 20min and separated by a centrifuge to obtain a supernatant. And (3) analyzing the concentration of the rhodamine B in the supernatant by using a UV spectrophotometer, thereby calculating the removal rate, and making a graph of the photocatalytic time and the rhodamine B removal rate.

The method comprises the steps of measuring the concentration of pollutants in dye sewage by using an ultraviolet spectrophotometer, firstly, preparing standard solutions with different concentrations by using deionized water as a reference, measuring the concentration of the solution by using the ultraviolet spectrophotometer, drawing a concentration-absorbance standard curve at the optimal wavelength for later use, and in the following experiment process, calculating the concentration of the adsorbed sewage by using the absorbance standard curve. The degradation rate is calculated according to a formula,

in the formula, C0 and Ct represent the concentration of rhodamine B before and after photodegradation respectively. Ultraviolet light was supplied by a 250W ultraviolet lamp and the concentration of rhodamine B dye was detected by an ultraviolet spectrophotometer.

According to the method, the Ag/AgBr graphene composite gel prepared in the embodiment 1 of the invention and the product prepared in the comparative example 1-2 are subjected to dye wastewater degradation test, the concentration of rhodamine B before reaction is 10mM/L, samples are taken every 20min, and the degradation rate is calculated, as shown in figure 2, after the Ag/AgBr graphene composite gel prepared in the embodiment 1 of the invention is tested for 2h, the degradation rate of rhodamine B reaches over 95 percent, which is far higher than that of the comparative example 1-2, and the fact that the Ag/AgBr graphene composite gel can effectively degrade rhodamine B is proved.

And (2) carrying out cycle test on the Ag/AgBr graphene composite gel prepared in the embodiment 1 of the invention, respectively taking 5 beakers, respectively adding 100ml of 10mM/L rhodamine B solution, marking as 1-5, sequentially putting the Ag/AgBr graphene composite gel prepared in the embodiment 1 of the invention into the beakers, and carrying out photocatalysis for 120 min. And then measuring the concentration of rhodamine B after each reaction, and making a curve of the reaction times and the removal rate.

As can be seen from fig. 3, after 5 times of continuous tests, the degradation rate of the Ag/AgBr graphene composite gel to rhodamine B is still higher than 90%, and the degradation rate is not significantly reduced in each test, which proves that the Ag/AgBr graphene composite gel prepared in embodiment 1 of the present invention can be recycled, and has good stability.