Background
At present, the variety of dyes all over 10 thousands of the world, the yield exceeds 700 million tons every year, and the production is still increasing, in the process of producing the dyes, the loss of the dyes and the discharge of printing and dyeing wastewater are often accompanied with the outflow of partial dyes, and in the process of printing and dyeing, the loss of the dyes and the discharge of printing and dyeing wastewater are also caused, so that serious environmental pollution is caused, especially, acid azo dyes such as methyl orange and the like which have stable chemical structure, strong oxidation resistance and toxicity and are difficult to degrade are directly discharged without being treated, so that an ecological system is seriously damaged, and further, the health of human beings is damaged.
The efficiency of the photocatalytic degradation method mainly depends on the selection of a photocatalyst, and at present, semiconductor photocatalytic materials such as ZnO and TiO are used 2 、WO 3 、SnO 2 The like have excellent photocatalytic performance and are widely applied to the fields of photocatalytic hydrogen production and degradation, wherein n-type semiconductor SnO 2 The material has the advantages of wide forbidden band width, low toxicity, high chemical stability, low cost, excellent photocatalytic activity and the like, is widely applied to the fields of gas sensing, lithium ion batteries, photocatalysis and the like, but has the advantages of easy recombination of photo-generated electrons and holes, low sunlight utilization rate, great restriction on the application range, modification treatment on the material is needed, and element doping can improve SnO 2 Overall performance of, and p-type semiconductor MoS 2 Has narrower forbidden bandwidth, better conductivity and excellent electrochemical and optical properties, is widely applied to the fields of lithium ion batteries, photocatalysis and the like, and is SnO 2 Compounding to obviously improve SnO 2 The graphene has the advantages of large specific surface area, good conductivity and the like, is widely applied to the fields of lithium ion batteries, photocatalysis, adsorption and the like, and can further improve the adsorption performance of the graphene on organic dyes such as methyl orange and the like through chemical modification.
Technical problem to be solved
Aiming at the defects of the prior art, the invention provides SnO applied to sewage treatment 2 -MoS 2 The modified graphene aerogel and the preparation method thereof solve the problem of SnO 2 The photo-generated electrons and holes of the photocatalyst are easy to recombine, the sunlight utilization rate is low, and the adsorption performance is poor.
(II) technical scheme
In order to achieve the purpose, the invention provides the following technical scheme: snO applied to sewage treatment 2 -MoS 2 Modified graphene aerogel, snO applied to sewage treatment 2 -MoS 2 The preparation method of the modified graphene aerogel comprises the following steps:
(1) Carrying out amination modification on graphene by using diethylenetriamine to obtain aminated graphene;
(2) Adding methanol solvent, diethylenetriamine, N-methylene bisacrylamide and aminated graphene into a three-necked bottle, performing uniform ultrasonic dispersion, performing reaction, removing the solvent by rotary evaporation, washing with acetone, and drying to obtain hyperbranched polyamidoamine functionalized graphene;
(3) Adding a deionized water solvent and sodium hydroxide into a three-mouth bottle, uniformly dispersing by ultrasonic treatment, dropwise adding a stannous chloride aqueous solution while performing ultrasonic treatment, adding sodium fluoride and a surfactant cetyl trimethyl ammonium bromide, uniformly dispersing by ultrasonic treatment, placing the mixture into a reaction kettle, performing hydrothermal reaction, cooling to room temperature, performing centrifugal separation, washing with deionized water and absolute ethyl alcohol, and drying to obtain fluorine-doped stannic oxide nanoflowers;
(4) Adding a deionized water solvent, thioacetamide, sodium molybdate and fluorine-doped tin oxide nanoflower into a three-necked bottle, performing ultrasonic dispersion uniformly, performing hydrolysis reaction, adding ethanol to promote dispersion, precipitating a product by using dilute hydrochloric acid, performing centrifugal separation, washing the product by using deionized water, drying the product, putting the dried product into a tubular furnace, calcining the product, and cooling the product to room temperature to obtain molybdenum disulfide hollow sphere modified fluorine-doped tin oxide nanoflower;
(5) Adding a deionized water solvent, molybdenum disulfide hollow spheres for modifying fluorine-doped tin oxide nanoflowers and hyperbranched polyamidoamine functionalized graphene into a three-necked bottle, uniformly dispersing by ultrasonic waves, placing the three-necked bottle in a reaction kettle, carrying out hydrothermal reaction, and carrying out freeze drying to obtain the fluorine-doped tin oxide nanoflowers and the hyperbranched polyamidoamine functionalized grapheneSnO applied to sewage treatment 2 -MoS 2 Modifying the graphene aerogel.
Preferably, in the step (2), the mass ratio of diethylenetriamine to N, N-methylene bisacrylamide to aminated graphene is 10-20.
Preferably, the reaction condition in the step (2) is reflux reaction at 45-60 ℃ for 6-9h.
Preferably, in the step (3), the mass ratio of the sodium hydroxide, the stannous chloride, the sodium fluoride and the hexadecyl trimethyl ammonium bromide is 60-120.
Preferably, the hydrothermal reaction condition in the step (3) is hydrothermal reaction at 140-200 ℃ for 24-32h.
Preferably, the mass ratio of thioacetamide, sodium molybdate and fluorine-doped stannic oxide nanoflower in the step (4) is 40-70.
Preferably, the hydrolysis reaction in the step (4) is carried out at 85-100 ℃ for 6-12min.
Preferably, the calcination in step (4) is performed under the condition of 700-800 ℃ in a hydrogen atmosphere for 0.5-2h.
Preferably, the mass ratio of the molybdenum disulfide hollow sphere modified fluorine doped stannic oxide nanoflower to the hyperbranched polyamidoamine functionalized graphene in the step (5) is 3-6.
Preferably, the hydrothermal reaction condition in the step (5) is hydrothermal reaction at 160-200 ℃ for 8-15h.
(III) advantageous technical effects
Compared with the prior art, the invention has the following beneficial technical effects:
SnO applied to sewage treatment 2 -MoS 2 The modified graphene aerogel takes aminated graphene as a central point, amino and imino on aminated graphene and diethylenetriamine and double bonds on N, N-methylene-bisacrylamide undergo a Michelal addition reaction to obtain hyperbranched polyamidoamine functionalized graphene, and Sn is reacted in an alkaline environment 2+ Rapid hydrolysis to Sn (OH) 2 And further oxidized to form Sn (OH) 4 Further with OH - Reaction to form Sn (OH) 6 2- Hydrothermal reaction to produce SnO 2 Nanocrystalline is coagulated and nucleated, and further directionally grows to form SnO along the direction of acting force with reduced surface energy under the action of cetyl trimethyl ammonium bromide serving as a surfactant 2 Further, the nanosheets grow randomly in other directions to form SnO 2 Nanometer flower and sodium fluoride as doping source to obtain F-doped SnO 2 Nano flower, snO 2 The unique nano flower-shaped morphology has an ultra-high specific surface area, is favorable for exposing photocatalytic degradation active sites, and takes the nano flower-shaped morphology as a substrate to accelerate the hydrolysis of thioacetamide with hydrochloric acid and high temperature to generate H 2 S, further reacting with sodium molybdate to dope SnO with F 2 In-situ growth of MoS on nanoflower x Seed crystals further in MoS x Precipitation of MoS on seed crystals x Generating MoS x Spherical nanoparticles, calcined, moS x Generating MoS 2 And H 2 Obtaining MoS 2 Hollow sphere modified F-doped SnO 2 Nanoflower, moS 2 The special hollow spherical shape has super-high specific surface area, is beneficial to exposing more photocatalytic degradation active sites, and further takes hyperbranched polyamidoamine functionalized graphene as a carrier and MoS 2 Hollow sphere modified F-doped SnO 2 The nano flower is used as an active substance to obtain SnO applied to sewage treatment 2 -MoS 2 Modifying the graphene aerogel.
SnO applied to sewage treatment 2 -MoS 2 The hyperbranched polyamidoamine functionalized graphene has an ultrahigh specific surface area, is beneficial to exposing more adsorption active sites, contains abundant amino groups and hydrogen bonds in the molecular structure of hyperbranched polyamidoamine, further exposes more adsorption active sites, and simultaneously protonates abundant amino groups in a weak acid environment, so that the hyperbranched polyamidoamine has more positive charges, increases the electrostatic attraction with organic dyes such as methyl orange with negative charges, and the hyperbranched polyamidoamine has excellent hydrophilicity, and forms a large number of cavity structures in the process of forming the hyperbranched polyamidoamine by a Michelal addition reaction, and has a synergistic effect with the grapheneIs beneficial to adsorbing more organic dyes such as methyl orange and the like.
SnO applied to sewage treatment 2 -MoS 2 Modifying graphene aerogel, and doping F atoms into SnO 2 In the crystal lattice of (2), promoting SnO 2 The nanocrystals are grown so that SnO 2 Further increase the specific surface area of the catalyst and simultaneously make SnO 2 The absorption band edge red shift widens SnO 2 Absorption of light in the range of SnO 2 Utilization ratio of sunlight, p-type semiconductor MoS 2 With n-type semiconductors SnO 2 Forming a p-n heterojunction structure such that MoS 2 And SnO 2 The Fermi energy levels of the contact surfaces are the same, so that energy bands near the contact surfaces are dislocated to form an internal electric field, and under the action of the internal electric field, photoproduction electrons and holes are promoted to pass through the contact surfaces to be separated, so that SnO is enabled 2 Hole transfer to MoS in the valence band 2 On the price band, and MoS 2 Transfer of photo-generated electrons on conduction band from SnO 2 The separation of photo-generated electrons and holes is promoted on the conduction band, the photo-generated electrons react with oxygen to generate superoxide anions, the holes react with water to generate hydroxyl radicals, and the superoxide anions and the hydroxyl radicals with strong oxidizing property can oxidize organic dyes such as methyl orange and the like into small molecular substances.
Detailed Description
To achieve the above object, the present invention provides the following embodiments and examples: snO applied to sewage treatment 2 -MoS 2 Modified graphene aerogel applied to SnO of sewage treatment 2 -MoS 2 The preparation method of the modified graphene aerogel comprises the following steps:
(1) Carrying out amination modification on graphene by using diethylenetriamine to obtain aminated graphene;
(2) Adding methanol solvent, diethylenetriamine, N-methylene bisacrylamide and aminated graphene into a three-necked bottle, wherein the mass ratio of the methanol solvent to the diethylenetriamine to the N, N-methylene bisacrylamide to the aminated graphene is 10-20;
(3) Adding a deionized water solvent and sodium hydroxide into a three-mouth bottle, uniformly dispersing by ultrasonic treatment, dropwise adding a stannous chloride aqueous solution while performing ultrasonic treatment, adding sodium fluoride and a surfactant cetyl trimethyl ammonium bromide, wherein the mass ratio of the sodium hydroxide to the stannous chloride to the sodium fluoride to the cetyl trimethyl ammonium bromide is (60-100);
(4) Adding a deionized water solvent, thioacetamide, sodium molybdate and fluorine-doped stannic oxide nanoflower into a three-neck flask, wherein the mass ratio of the deionized water solvent to the thioacetamide to the sodium molybdate to the fluorine-doped stannic oxide nanoflower is 40-70;
(5) Adding a deionized water solvent, molybdenum disulfide hollow spheres modified fluorine-doped tin oxide nanoflowers and hyperbranched polyamidoamine functionalized graphene into a three-mouth bottle, wherein the mass ratio of the two is 3-6, the two is uniformly dispersed by ultrasonic, placing the three-mouth bottle into a reaction kettle, carrying out hydrothermal reaction at 160-200 ℃ for 8-15h, and carrying out freeze drying to obtain SnO applied to sewage treatment 2 -MoS 2 Modifying the graphene aerogel.
Example 1
(1) Carrying out amination modification on graphene by using diethylenetriamine to obtain aminated graphene;
(2) Adding methanol solvent, diethylenetriamine, N-methylene bisacrylamide and aminated graphene into a three-necked bottle, wherein the mass ratio of the methanol solvent to the diethylenetriamine to the N, N-methylene bisacrylamide to the aminated graphene is 10;
(3) Adding a deionized water solvent and sodium hydroxide into a three-neck flask, uniformly dispersing by ultrasonic treatment, dropwise adding a stannous chloride aqueous solution while ultrasonically treating, adding sodium fluoride and a surfactant cetyl trimethyl ammonium bromide, wherein the mass ratio of the sodium hydroxide to the stannous chloride to the sodium fluoride to the cetyl trimethyl ammonium bromide is 60;
(4) Adding a deionized water solvent, thioacetamide, sodium molybdate and fluorine-doped tin oxide nanoflower into a three-neck flask, wherein the mass ratio of the deionized water solvent to the thioacetamide to the sodium molybdate to the fluorine-doped tin oxide nanoflower is 40;
(5) Adding a deionized water solvent, molybdenum disulfide hollow spheres to modify fluorine-doped tin oxide nanoflowers and hyperbranched polyamidoamine functionalized graphene into a three-mouth bottle, wherein the mass ratio of the two is 3 2 -MoS 2 Modifying the graphene aerogel.
Example 2
(1) Carrying out amination modification on graphene by using diethylenetriamine to obtain aminated graphene;
(2) Adding methanol solvent, diethylenetriamine, N-methylene bisacrylamide and aminated graphene into a three-necked bottle, wherein the mass ratio of the three is 13.5;
(3) Adding a deionized water solvent and sodium hydroxide into a three-mouth bottle, uniformly dispersing by ultrasonic treatment, dropwise adding a stannous chloride aqueous solution while ultrasonically treating, adding sodium fluoride and a surfactant, namely cetyl trimethyl ammonium bromide, wherein the mass ratio of the sodium hydroxide to the stannous chloride to the sodium fluoride to the cetyl trimethyl ammonium bromide is (80);
(4) Adding a deionized water solvent, thioacetamide, sodium molybdate and fluorine-doped tin oxide nanoflower into a three-necked bottle, wherein the mass ratio of the deionized water solvent to the thioacetamide to the sodium molybdate to the fluorine-doped tin oxide nanoflower is 50;
(5) Adding a deionized water solvent, molybdenum disulfide hollow sphere modified fluorine-doped stannic oxide nanoflower and hyperbranched polyamidoamine functionalized graphene into a three-necked flask, wherein the mass ratio of the two is 4 2 -MoS 2 Modifying the graphene aerogel.
Example 3
(1) Carrying out amination modification on graphene by using diethylenetriamine to obtain aminated graphene;
(2) Adding methanol solvent, diethylenetriamine, N-methylene bisacrylamide and aminated graphene into a three-necked bottle, wherein the mass ratio of the methanol solvent to the diethylenetriamine to the N, N-methylene bisacrylamide to the aminated graphene is 17;
(3) Adding a deionized water solvent and sodium hydroxide into a three-mouth bottle, uniformly dispersing by ultrasonic treatment, dropwise adding a stannous chloride aqueous solution while ultrasonically treating, adding sodium fluoride and a surfactant cetyl trimethyl ammonium bromide, wherein the mass ratio of the sodium hydroxide to the stannous chloride to the sodium fluoride to the cetyl trimethyl ammonium bromide is (100);
(4) Adding a deionized water solvent, thioacetamide, sodium molybdate and fluorine-doped tin oxide nanoflower into a three-neck flask, wherein the mass ratio of the deionized water solvent to the thioacetamide to the sodium molybdate to the fluorine-doped tin oxide nanoflower is 60;
(5) Adding a deionized water solvent, molybdenum disulfide hollow sphere modified fluorine-doped stannic oxide nanoflower and hyperbranched polyamidoamine functionalized graphene into a three-neck flask, wherein the mass ratio of the two is 5 2 -MoS 2 Modifying the graphene aerogel.
Example 4
(1) Carrying out amination modification on graphene by using diethylenetriamine to obtain aminated graphene;
(2) Adding methanol solvent, diethylenetriamine, N-methylene bisacrylamide and aminated graphene into a three-necked bottle, wherein the mass ratio of the methanol solvent to the diethylenetriamine to the N, N-methylene bisacrylamide to the aminated graphene is 20;
(3) Adding a deionized water solvent and sodium hydroxide into a three-neck flask, uniformly dispersing by ultrasonic treatment, dropwise adding a stannous chloride aqueous solution while ultrasonically treating, adding sodium fluoride and a surfactant cetyl trimethyl ammonium bromide, wherein the mass ratio of the sodium hydroxide to the stannous chloride to the sodium fluoride to the cetyl trimethyl ammonium bromide is (120);
(4) Adding a deionized water solvent, thioacetamide, sodium molybdate and fluorine-doped stannic oxide nanoflower into a three-neck flask, wherein the mass ratio of the deionized water solvent to the thioacetamide to the sodium molybdate to the fluorine-doped stannic oxide nanoflower is 70;
(5) Adding a deionized water solvent, molybdenum disulfide hollow spheres modified fluorine-doped stannic oxide nanoflower and hyperbranched polyamidoamine functionalized graphene into a three-necked bottle, wherein the mass ratio of the deionized water solvent to the molybdenum disulfide hollow spheres modified fluorine-doped stannic oxide nanoflower to the hyperbranched polyamidoamine functionalized graphene is 6 2 -MoS 2 Modifying the graphene aerogel.
Comparative example 1
(1) Carrying out amination modification on graphene by using diethylenetriamine to obtain aminated graphene;
(2) Adding methanol solvent, diethylenetriamine, N-methylene bisacrylamide and aminated graphene into a three-necked bottle, wherein the mass ratio of the methanol solvent to the diethylenetriamine to the N, N-methylene bisacrylamide to the aminated graphene is 8;
(3) Adding a deionized water solvent and sodium hydroxide into a three-neck flask, uniformly dispersing by ultrasonic treatment, dropwise adding a stannous chloride aqueous solution while ultrasonically treating, adding sodium fluoride and a surfactant cetyl trimethyl ammonium bromide, wherein the mass ratio of the sodium hydroxide to the stannous chloride to the sodium fluoride to the cetyl trimethyl ammonium bromide is 48;
(4) Adding a deionized water solvent, thioacetamide, sodium molybdate and fluorine-doped tin oxide nanoflower into a three-neck flask, wherein the mass ratio of the deionized water solvent to the thioacetamide to the sodium molybdate to the fluorine-doped tin oxide nanoflower is 32;
(5) Adding a deionized water solvent, molybdenum disulfide hollow spheres modified fluorine-doped stannic oxide nanoflowers and hyperbranched polyamidoamine functionalized graphene into a three-necked flask, wherein the mass ratio of the deionized water solvent to the molybdenum disulfide hollow spheres modified fluorine-doped stannic oxide nanoflowers to the hyperbranched polyamidoamine functionalized graphene is 2.4, dispersing the mixture uniformly by ultrasonic, placing the mixture into a reaction kettle, carrying out hydrothermal reaction for 8 hours at 160 ℃, and carrying out freeze drying to obtain SnO applied to sewage treatment 2 -MoS 2 Modifying the graphene aerogel.
Comparative example 2
(1) Carrying out amination modification on graphene by using diethylenetriamine to obtain aminated graphene;
(2) Adding methanol solvent, diethylenetriamine, N-methylene bisacrylamide and aminated graphene into a three-necked bottle, wherein the mass ratio of the methanol solvent to the diethylenetriamine to the N, N-methylene bisacrylamide to the aminated graphene is 24;
(3) Adding a deionized water solvent and sodium hydroxide into a three-neck flask, uniformly dispersing by ultrasonic treatment, dropwise adding a stannous chloride aqueous solution while ultrasonically treating, adding sodium fluoride and a surfactant cetyl trimethyl ammonium bromide, wherein the mass ratio of the sodium hydroxide to the stannous chloride to the sodium fluoride to the cetyl trimethyl ammonium bromide is 144;
(4) Adding a deionized water solvent, thioacetamide, sodium molybdate and fluorine-doped stannic oxide nanoflower into a three-neck flask, wherein the mass ratio of the deionized water solvent to the thioacetamide to the sodium molybdate to the fluorine-doped stannic oxide nanoflower is 84;
(5) Adding a deionized water solvent, molybdenum disulfide hollow spheres modified fluorine-doped stannic oxide nanoflowers and hyperbranched polyamidoamine functionalized graphene into a three-necked bottle, wherein the mass ratio of the deionized water solvent to the molybdenum disulfide hollow spheres modified fluorine-doped stannic oxide nanoflowers to the hyperbranched polyamidoamine functionalized graphene is 7.2, dispersing the mixture uniformly by ultrasonic, placing the mixture into a reaction kettle, carrying out hydrothermal reaction for 15 hours at 200 ℃, and carrying out freeze drying to obtain SnO applied to sewage treatment 2 -MoS 2 Modifying the graphene aerogel.
10mg of SnO applied to sewage treatment and obtained in example and comparative example and applied to sewage treatment were added to 50mL of methyl orange solution with a mass concentration of 20mg/L 2 -MoS 2 Modifying the graphene aerogel, uniformly dispersing, adjusting the pH value of the solution to 6, stirring for 90min at 25 ℃, centrifuging to remove solids to obtain a degraded solution, measuring the concentration of methyl orange in the solution by using an L5 type ultraviolet-visible spectrophotometer, and calculating the adsorption rate.
10mg of SnO applied to sewage treatment and obtained in example and comparative example and applied to sewage treatment were added to 50mL of methyl orange solution with a mass concentration of 20mg/L 2 -MoS 2 Modifying the graphene aerogel, uniformly dispersing, adjusting the pH value of the solution to 6, irradiating for 90min by using a 500W xenon lamp, centrifuging to remove solids to obtain a degraded solution, measuring the concentration of methyl orange in the solution by using an L5 type ultraviolet-visible spectrophotometer, and calculating the degradation rate.