CN110743564A

CN110743564A - MnFeO Fenton catalyst based on lignin and preparation method thereof

Info

Publication number: CN110743564A
Application number: CN201911149605.6A
Authority: CN
Inventors: 冯德鑫; 梁凤兵; 咸漠; 刘卫敏
Original assignee: Qingdao Institute of Bioenergy and Bioprocess Technology of CAS
Current assignee: Qingdao Institute of Bioenergy and Bioprocess Technology of CAS
Priority date: 2019-11-21
Filing date: 2019-11-21
Publication date: 2020-02-04

Abstract

The invention discloses a MnFeO Fenton catalyst based on lignin and a preparation method thereof, belonging to the technical field of environment functional materials. The invention aims to improve the redox reaction cycle stability and the pH application range of the existing heterogeneous Fenton-like catalyst. The method comprises the steps of loading iron ions and manganese ions on lignin by using an impregnation method, filtering, drying, calcining, washing and drying to obtain the MnFeO Fenton catalyst based on the lignin. The MnFeO Fenton catalyst prepared by the method disclosed by the invention is adaptive to a pH value range of 3-9, solves the problems of poor redox reaction cycle stability and low pH application range of a heterogeneous iron-based Fenton catalyst, and can replace the traditional Fenton catalyst to be used for advanced treatment of organic wastewater. In addition, the invention also has the advantages of simple preparation method, low process cost and the like.

Description

MnFeO Fenton catalyst based on lignin and preparation method thereof

Technical Field

The invention relates to a MnFeO Fenton catalyst based on lignin and a preparation method thereof, belonging to the technical field of environment functional materials.

Background

Lignin is a widely-existing renewable aromatic polymer known as one of the most abundant green resources available to humans in the 21 st century. About 5000 million tons of industrial lignin byproducts are separated from plants every year in the pulping and papermaking industry, but more than 95 percent of lignin is not separated and is directly discharged into rivers or is directly combusted after being concentrated. If the lignin can be fully utilized, not only can the environmental pollution be reduced, but also the biomass resources can be effectively utilized, thereby achieving the purposes of energy conservation and emission reduction.

The Fenton oxidation technology is a novel advanced oxidation technology and has an important effect on the treatment of organic wastewater. However, the fenton reaction also has certain disadvantages: if the pH value range of the reaction system is narrow, the general application range is 3-5; when the water treatment is finished, residual iron ions enable the solution to have color; h₂O₂Large dosage and high treatment cost.

The research and development of the heterogeneous Fenton-like catalyst are important ways for solving the problems in the using process of the traditional Fenton technology. At present, heterogeneous Fenton-like catalysts are mainly iron-based catalysts, such as iron-containing oxides (e.g. FeOOH, Fe)₂O₃，Fe₃O₄) And iron simple substance. However, iron-based multiphase fenton systems still face challenges, mainly due to the tight pH control required to prevent iron precipitation and the poor redox cycling stability. It is therefore desirable to provide a wider range of pH values for adaptation.

Disclosure of Invention

The invention provides a MnFeO Fenton-like catalyst based on lignin and a preparation method thereof, aiming at improving the pH application range of the existing heterogeneous Fenton-like catalyst.

The technical scheme of the invention is as follows:

a MnFeO Fenton catalyst based on lignin is prepared through loading iron ions and manganese ions on lignin by immersion method, drying, calcining, washing and drying.

The preparation method of the catalyst comprises the following operation steps:

mixing an iron ion aqueous solution with the concentration of 0.01-2 mol/L and a manganese ion aqueous solution with the concentration of 0.01-2 mol/L with lignin, uniformly stirring, adjusting the solution to be neutral, performing immersion treatment for 6 hours, filtering, and drying the solid precipitate;

and step two, placing the solid precipitate in a carbonization furnace, calcining under the protection of inert gas at the temperature of 300-1200 ℃ for 4h, washing, and drying to obtain the lignin-based MnFeO Fenton catalyst.

Further limiting, in the step one, the kind of iron ion is Fe²⁺、Fe³⁺One or two of them.

Further limiting, in the first step, the manganese ion species is Mn²⁺。

Further limiting, in the step one, the lignin is one or more of alkali lignin, sulfate lignin, enzymatic hydrolysis lignin, acid hydrolysis lignin and lignosulfonate mixed in any proportion.

Further, the mass ratio of the iron ions to the manganese ions in the first step is 1 (0.01-1).

Further limiting, in the step one, the mass ratio of the total mass of the iron ions and the manganese ions to the lignin is 1 (1-100).

Further limiting, the mass ratio of the total mass of the iron ions and the manganese ions to the lignin is 1 (2-10).

Further defined, the mass ratio of the iron ions to the manganese ions is 1: 0.33.

Further limiting, the calcining temperature in the second step is 600-900 ℃.

The invention has the beneficial effects that:

the MnFeO Fenton catalyst prepared by the method disclosed by the invention is suitable for a pH value range of 3-9, and the added Mn metal can replace Fe to play a catalytic role in hydrogen peroxide, so that the application range of the catalyst is widened. The problem of low pH application range of the Fenton-like catalyst is solved, and the Fenton-like catalyst can be used for advanced treatment of organic wastewater instead of the traditional Fenton-like catalyst. In addition, the invention also has the advantages of simple preparation method, low process cost and the like.

Drawings

FIG. 1 is an electron microscope scan of MnFeO Fenton-like catalyst.

Detailed Description

The experimental procedures used in the following examples are conventional unless otherwise specified.

Embodiment mode 1:

100mL of iron ion aqueous solution (0.01mol/L) and 30mL of manganese ion aqueous solution (0.01mol/L) were mixed with 0.112g of alkali lignin, stirred uniformly, adjusted to pH 6, and immersed for 6 hours. After filtration the solid precipitate was dried in an oven. Then placing the dried solid precipitate in a carbonization furnace in inert gas N₂Under protection, rapidly heating to 900 ℃, calcining for 4h, ultrasonically washing with deionized water to remove ionic iron, finally cleaning with ethanol to remove organic impurities on the surface, and finally drying in an oven to obtain the MnFeO Fenton catalyst.

Comparative example 1:

100mL of iron ion aqueous solution (0.01mol/L) and 0.112g of alkali lignin were mixed, stirred uniformly, adjusted to pH 6, and immersed for 6 hours. After filtration the solid precipitate was dried in an oven. Then placing the dried solid precipitate in a carbonization furnace in inert gas N₂Under protection, rapidly heating to 900 ℃, calcining for 4h, ultrasonically washing with deionized water to remove ionic iron, finally cleaning with ethanol to remove organic impurities on the surface, and finally drying in an oven to obtain the iron-based Fenton catalyst.

The MnFeO Fenton-like catalyst and the iron-based Fenton-like catalyst prepared in the specific embodiment 1 and the comparative example 1 are respectively matched with hydrogen peroxide for use, so that rhodamine B is catalytically degraded (the rhodamine B is used for simulating wastewater), and the catalytic degradation performance of the catalyst is represented by measuring the decolorization rate of the rhodamine B. The specific operation process is as follows:

(1) MnFeO fenton-like catalyst: at normal temperature, 100mL of 100mg/L rhodamine B aqueous solution is added into a 250mL conical flask with a plug, and then 0.1g of 30% H is added₂O₂And 0.1g of a MnFeO Fenton-like catalyst obtained in accordance with embodiment 1, using a sodium hydroxide standard solutionAnd adjusting the pH value of the solution and the hydrochloric acid standard solution to a selected value, stirring at the rotating speed of 150r/min for 1h, and measuring and recording the decolorization rate of the rhodamine B.

(2) Iron-based fenton-like catalyst: at normal temperature, 100mL of 100mg/L rhodamine B aqueous solution is added into a 250mL conical flask with a plug, and then 0.1g of 30% H is added₂O₂The iron-based Fenton catalyst prepared in the comparative example 1 is adjusted to a selected value of pH, stirred for 1 hour at a rotating speed of 150r/min, and the decolorization rate of rhodamine B is measured and recorded.

The results of the above tests are shown in the following table:

as can be seen from the above table, the MnFeO Fenton-like catalyst has a wider pH application range.

Claims

1. The MnFeO Fenton-like catalyst based on lignin is characterized in that the Fenton-like catalyst is prepared by loading iron ions and manganese ions on the lignin by adopting an impregnation method, and then drying, calcining, washing and drying the iron ions and the manganese ions in sequence.

2. The method for preparing MnFeO Fenton-like catalyst based on lignin according to claim 1, wherein the method comprises the following steps:

3. The method for preparing MnFeO Fenton-like catalyst based on lignin according to claim 2The preparation method is characterized in that the iron ion species in the step one is Fe²⁺、Fe³⁺One or two of them.

4. The method of claim 2, wherein the manganese ion species in the first step is Mn²⁺。

5. The method for preparing MnFeO Fenton-like catalyst based on lignin according to claim 2, wherein the lignin in the first step is one or more of alkali lignin, sulfate lignin, enzyme hydrolysis lignin, acid hydrolysis lignin and lignosulfonate.

6. The method for preparing MnFeO Fenton-like catalyst based on lignin according to claim 2, wherein the mass ratio of iron ions to manganese ions in the first step is 1 (0.01-1).

7. The method for preparing MnFeO Fenton-like catalyst based on lignin according to claim 6, wherein the mass ratio of iron ion to manganese ion is 1: 0.33.

8. The method for preparing a MnFeO Fenton-like catalyst based on lignin according to claim 2, wherein the mass ratio of the total mass of iron ions and manganese ions to lignin in the first step is 1 (1-100).

9. The method for preparing a MnFeO Fenton-like catalyst based on lignin according to claim 8, wherein the mass ratio of the total mass of iron ions and manganese ions to the mass of the lignin is 1 (2-10).

10. The method for preparing MnFeO Fenton-like catalyst based on lignin according to claim 9, wherein the calcination temperature in the second step is 600-900 ℃.