阅读说明：本技术 一种快速降解孔雀石绿的Ag2MoO4/Ag2O材料制备方法 (Ag capable of rapidly degrading malachite green2MoO4/Ag2Preparation method of O material ) 是由 韦寿莲 张俊权 黄象金 谢春生 于 2019-09-27 设计创作，主要内容包括：本发明公开了一种快速降解孔雀石绿的类芬顿催化剂Ag_2MoO_4/Ag_2O材料、制备方法及其应用。以磷酸氢二钠、钼酸钠和硝酸银为原料,利用化学沉淀法,协同水热法自掺杂氧化银合成新型的Ag_2MoO_4/Ag_2O类芬顿催化剂,其中确定了合成反应最佳的pH、钼酸钠和硝酸银的投料比、水热反应的条件；该催化剂与H_2O_2混合后在合适的pH环境下能够应用于高效降解孔雀石绿。研究发现,Ag_2MoO_4/Ag_2O-H_2O_2非均相类芬顿复合体系在6min内对孔雀石绿的脱色率高达99.7％。本发明的光催化剂制备方法简单,易操作,具有低毒、低价等优势,在降解有机染料领域具有非常高的研究价值。(The invention discloses a Fenton-like catalyst Ag for rapidly degrading malachite green 2 MoO 4 /Ag 2 O material, preparation method and application thereof. Disodium hydrogen phosphate, sodium molybdate and silver nitrate are used as raw materials, a chemical precipitation method is utilized, and a hydrothermal method is cooperated to self-dope silver oxide to synthesize novel Ag 2 MoO 4 /Ag 2 O-type Fenton catalyst, wherein the optimal pH value of the synthetic reaction, the feeding ratio of sodium molybdate and silver nitrate and the conditions of the hydrothermal reaction are determined; the catalyst and H 2 O 2 After mixing are in placeCan be applied to degrading malachite green with high efficiency in a pH environment. The research finds that Ag 2 MoO 4 /Ag 2 O‑H 2 O 2 The decolorization rate of the heterogeneous Fenton-like complex system on malachite green within 6min is as high as 99.7%. The photocatalyst provided by the invention is simple in preparation method, easy to operate, low in toxicity, low in price and the like, and has very high research value in the field of organic dye degradation.)

1. Fenton-like catalyst Ag capable of rapidly degrading malachite green₂MoO₄/Ag₂The preparation method of the O material is characterized by comprising the following steps:

(1)Na₂MoO₄·2H₂o and Na₂HPO₄·12H₂Mixing the O solution, and stirring in a beaker for reaction;

(2) adding appropriate amount of HNO into (1)₃Solution, dropwise adding AgNO₃Continuously stirring the solution for reaction, slowly adding a NaOH solution to adjust the pH value of the reaction solution, and standing;

(3) discarding most of supernatant in the step (2), transferring the residual suspension into a high-pressure reaction kettle with a polytetrafluoroethylene lining, reacting in a constant-temperature box, and performing suction filtration to obtain a precipitate;

(4) washing the precipitate with purified water for 3 times, transferring to crucible, and drying in vacuum oven at constant temperature.

2. The Fenton-like catalyst Ag for rapidly degrading malachite green according to claim 1₂MoO₄/Ag₂The preparation method of the O material is characterized in that the Na in the step (1)₂MoO₄·2H₂The concentration of the O solution is 1.2mol/L, Na₂HPO₄·12H₂The concentration of the O solution is 0.1mol/L, Na₂MoO₄·2H₂O and Na₂HPO₄·12H₂And mixing and stirring O according to the feeding molar ratio of 12:1 for reaction for 5-15 min.

3. The method for preparing Fenton-like catalyst Ag2MoO4/Ag2O material for rapidly degrading malachite green as claimed in claim 1, wherein the AgNO of step (2)₃The solution concentration is 0.6mol/L, HNO is added firstly₃The solution is then added dropwise with AgNO₃A solution; AgNO₃The amount of (B) is determined according to Na₂MoO₄·2H₂Dependent on the amount of O, AgNO₃With Na₂MoO₄·2H₂The molar ratio of O is 1: 2.5-1: 4.

4. The method for preparing Fenton-like catalyst Ag2MoO4/Ag2O material for rapidly degrading malachite green as claimed in claim 1, wherein the concentration of NaOH solution in step (2) is 4mol/L, the pH of the solution after reaction in step (2) is adjusted to 6.8-8.0, and the solution is left for 20-30 min to clarify the upper turbid solution.

5. The method for preparing Fenton-like catalyst Ag2MoO4/Ag2O material for rapidly degrading malachite green as claimed in claim 1, wherein the reaction conditions of the autoclave in step (3) are as follows: the reaction solution is 12-20 mL, the temperature is 100-140 ℃, and the constant temperature reaction time is 12-18 h.

6. The preparation method of Fenton-like catalyst Ag2MoO4/Ag2O material for rapidly degrading malachite green as claimed in claim 1, wherein the vacuum drying temperature in step (4) is 80-100 ℃; the drying time is 12-15 h.

7. Fenton-like catalyst Ag capable of rapidly degrading malachite green₂MoO₄/Ag₂O material, characterized in that the Fenton-like catalyst Ag₂MoO₄/Ag₂The O material is prepared by the method of any one of claims 1 to 6.

8. Fenton-like catalyst Ag prepared by the method of any one of claims 1 to 6₂MoO₄/Ag₂The application of the O material in degrading organic dye or malachite green in wastewater.

Technical Field

The invention relates to the field of catalytic degradation of organic pollutants, in particular to Ag₂MoO₄/Ag₂Preparation method and catalytic condition of O.

Background

Because high-level electrons in the simple substance silver are easy to be combined with low-level holes under the action of coulomb attraction, the photocatalytic activity of the simple substance silver is not high, and the silver material really showing high photocatalytic activity is a silver compound, and comprises silver-containing halides, oxides, sulfides, metal oxides, oxysalts and the like. Hu et Al also prepare surface plasma photocatalyst Ag/AgI/Al through coprecipitation method and photoreduction method₂O₃The material also shows high-efficiency photocatalytic activity and stability; yi and the like utilize simple ion exchange reaction to prepare the Ag with high degradation efficiency₃PO₄A photocatalyst capable of completely decolorizing the dye within minutes; guo et al synthesized Fe by hydrothermal method and ion exchange method₃O₄@Ag₃PO₄The catalyst/AgCl is used for irradiating methylene blue by visible light, completely degrading the methylene blue in 60min, and performing a cycle experiment, wherein the catalytic activity and the magnetism are basically unchanged after 5 times. These show that the silver-based material has very good application prospect in the field of catalysis.

Malachite Green (MG) is a Green crystal with metallic luster, is easily soluble in water, and is soluble in ethanol, methanol and pentanol; it is a toxic triphenylmethane chemical, a dye, and a fungicide, bactericide, and parasiticide. With the development of textile industry and agriculture, dyes and pesticides are used in large quantities, so that organic toxic substances such as MG and the like enter environmental water more and more, and the environment and organisms are greatly influenced if the metabolic products are not treated properly due to the complexity of the metabolic products. Therefore, the search for a catalyst capable of efficiently catalyzing and degrading MG has attracted extensive attention of researchers.

The method for degrading MG by using microwave-Fenton oxidation process of India madder also obtains better resultsGood effect, but because it is Fe²⁺/H₂O₂The system and the pH have limited application range, and the iron ions are difficult to recover after the reaction, thereby increasing the operation cost in the early stage and the difficulty in the later stage recovery. The fenton-like technology can effectively solve the defects. Lihai such as NiFe₂O₄-H₂O₂MG is degraded by the system, the reaction lasts for 30min, and the decolorization rate can reach more than 98 percent; job's wort, etc. utilizing Fe/Ce/modified natural zeolite-H₂O₂MG is degraded by the system, and the decolorization rate can reach 97.3 percent after 30min of the same reaction; utilization of Mg-Al LDHs-H by plum rain and sweet₂O₂MG is degraded in the system, and reacts for 45min to reach 98 percent of decolorization rate. Therefore, the existing catalysts for degrading MG by using the iron Fenton-like system have the defects of long degradation time and complex synthesis steps, and also have the problems of troublesome catalyst recovery and the like, so that the further utilization of the catalysts is limited, and the secondary pollution to the environment is caused. In recent years, silver salts include Ag₂O、Ag₂MoO₄The photocatalyst has been successfully applied to photocatalytic degradation of pollutants such as methyl orange, Cr (VI), and the like, but the silver salt and H are rarely used₂O₂The Fenton-like system is applied to catalytic degradation of organic dyes. Compared with other noble metals, the silver salt has the advantages of low toxicity, low price and the like, so that the Fenton-like system formed based on the silver salt has a very good application prospect.

Disclosure of Invention

Aiming at the problems, the invention provides a preparation method and catalysis conditions of a silver-based Fenton heterogeneous catalyst for efficiently catalyzing and degrading MG.

The invention provides a preparation method of a silver-based Fenton heterogeneous catalyst for catalyzing and degrading MG, which comprises the following steps:

preparation of Ag by hydrothermal method₂MoO₄/Ag₂O complex:

(1)Na₂MoO₄·2H₂o and Na₂HPO₄·12H₂Mixing the O solution according to a certain proportion, and stirring in a beaker for reaction;

(2) adding appropriate amount of HNO into (1)₃Solution, dropwise adding AgNO₃Continuously stirring the solution for reaction for a period of time, slowly adding NaOH solution to adjust the pH value of the reaction solution, and standing;

(3) discarding most of supernatant in the step (2), transferring the residual suspension into a high-pressure reaction kettle with a polytetrafluoroethylene lining, reacting in a constant-temperature box, and performing suction filtration to obtain a precipitate;

(4) washing the precipitate with purified water for 3 times, transferring to crucible, and drying in vacuum oven at constant temperature.

According to a possible mode of the first aspect of the present invention, the Na in the step (1)₂MoO₄·2H₂The concentration of the O solution is 1.2mol/L, Na₂HPO₄·12H₂The concentration of the O solution is 0.1mol/L, Na₂MoO₄·2H₂O and Na₂HPO₄·12H₂The feeding ratio of the O stirring reaction is 12:1, and the reaction time is 5-15 min;

according to one mode of the invention, the AgNO in the step (2)₃The solution concentration is 0.6mol/L, HNO is added firstly₃The solution is then added dropwise with AgNO₃Stirring the solution for reaction for 10-25 min; AgNO₃With Na₂MoO₄·2H₂The molar ratio of O is 1: 2.5-1: 4.

According to one implementation mode of the first aspect of the invention, the concentration of the NaOH solution in the step (2) is 4mol/L, the pH of the solution after the reaction in the step (2) is adjusted to 6.8-8.0, and the solution is kept stand for 20-30 min even if the turbid solution above the pH is clear;

according to a mode capable of realizing the first aspect of the invention, the reaction conditions of the burning kettle in the step (3) are that a kettle required by the reaction is a 25mL high-pressure reaction kettle with a polytetrafluoroethylene lining, the reaction solution is 12-20 mL, the temperature is 100-140 ℃, and the constant-temperature reaction time is 12-18 h;

according to one implementation manner of the first aspect of the invention, the vacuum drying temperature in the step (4) is 80-100 ℃; the drying time is 12-15 h.

In a second aspect, the present invention provides a silver-based Fenton-like heterogeneous catalyst prepared according to the above method.

The third aspect of the invention also provides the application of the silver-based Fenton-like heterogeneous catalyst prepared by the method. Preferably, the application comprises: the dosage of the catalyst in the catalytic degradation of pollutants is 0.5-1.0 g/L, H₂O₂The dosage is 49-82 mmol/L, the temperature is 35-40 ℃, and the pH range is 5.0-7.0. Wherein the pollutant is organic dye or malachite green in wastewater.

The invention has the beneficial effects that:

aiming at the defects of the prior art, the invention optimizes Ag₂MoO₄/Ag₂The synthesis method of O takes malachite green as a degradation pollutant, and further optimizes the catalysis condition, so that the synthesized silver-based Fenton heterogeneous catalyst compound has the characteristics of short decolorization time, high decolorization efficiency, wider pH range of use, high reuse rate, simple preparation process and the like on the malachite green, and has wide application prospect in degrading the malachite green in wastewater.

Drawings

The invention is further illustrated by means of the attached drawings, but the embodiments in the drawings do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be obtained on the basis of the following drawings without inventive effort.

FIG. 1 shows Ag obtained by a method according to an exemplary embodiment of the present invention₂MoO₄/Ag₂XRD characterization results of the O material;

FIG. 2 shows Ag obtained by a method according to an exemplary embodiment of the present invention₂MoO₄/Ag₂FT-IR characterization of O materials;

FIG. 3 shows Ag obtained by a method according to an exemplary embodiment of the present invention₂MoO₄/Ag₂Schematic effect diagram of catalytic degradation of MG by using O material and comparative example, wherein: 1.Ag⁺；2.Ag⁺+H₂O₂；3.Ag₂MoO₄/Ag₂O；4.H₂O₂；5.Ag₂MoO₄；6.Ag₂MoO₄+H₂O₂；7.Ag₂O；8.Ag₂O+H₂O₂；9.Ag₂MoO₄/Ag₂O+H₂O₂；

FIG. 4 shows Ag obtained by a method according to an exemplary embodiment of the present invention₂MoO₄/Ag₂A decolorization rate diagram of degradation of MG by O material under preferred decolorization conditions;

FIG. 5 shows Ag obtained by a method according to an exemplary embodiment of the present invention₂MoO₄/Ag₂Effect of reusing decolorized MG for O material is shown schematically.

Detailed Description

The invention is further described with reference to the following examples.