Titanium black electrode material and preparation method and application thereof

Abstract

The invention relates to the technical field of wastewater treatment, and discloses a titanium black electrode material as well as a preparation method and application thereof. The invention provides a titanium black electrode material. The titanium black electrode material is composed of a modified graphene oxide layer, a titanium black layer and a modified iron-based metal organic framework material layer in sequence from top to bottom. According to the titanium black electrode material provided by the invention, the removal rate of COD (Chemical Oxygen Demand) in wastewater can reach 96.14%, and the titanium black electrode material has a good removal effect on the COD in the wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a titanium dioxide electrode material and a preparation method and application thereof. Background Art

[0002] Chemical oxygen demand (COD) is a key indicator for measuring the content of organic pollutants in wastewater. Its effective removal is of great significance for achieving wastewater discharge standards and environmental protection. Currently, common COD removal methods include physical, chemical, and biological methods. Physical methods such as sedimentation and filtration can only remove suspended particles and some colloidal substances in wastewater, and are not effective in removing soluble organic pollutants, and cannot meet the needs of deep treatment. Among chemical methods, although the Fenton oxidation method has strong oxidation ability, it requires the addition of a large amount of chemical agents, is costly, and is prone to secondary pollution; the ozone oxidation method requires large equipment investment, high operating costs, and low ozone utilization. Although biological methods have the advantages of low cost and environmental friendliness, their treatment efficiency is relatively low and they have strict requirements on water quality and environmental conditions. For example, when the wastewater has poor biodegradability, large water quality fluctuations, or contains toxic substances, the biological treatment effect will be significantly affected, and it is difficult to ensure a stable COD removal rate.

[0003] With the rapid development of industry, wastewater composition is becoming increasingly complex, placing higher demands on COD removal technologies. Developing efficient, economical, and environmentally friendly COD removal technologies has become a research hotspot. Among these diverse research areas, electrochemical advanced oxidation technology (AEOT) has garnered widespread attention due to its strong oxidation capacity, rapid reaction speed, lack of secondary pollution, and ease of operation.

[0004] The core of electrochemical advanced oxidation technology is the anode material, whose performance directly affects the COD removal effect and energy consumption. Traditional anode materials such as graphite electrodes have poor conductivity, low mechanical strength, easy corrosion, and short service life; although precious metal electrodes (such as platinum, ruthenium, etc.) have high catalytic activity, they are expensive, which limits their large-scale application; titanium-based metal oxide electrodes (such as Ti / RuO2, Ti / IrO2, etc.) have problems such as poor stability, easy deactivation, and low oxygen evolution overpotential. In the treatment of high-concentration organic wastewater, anode passivation is prone to occur, resulting in a decrease in treatment efficiency. Therefore, providing a titanium dioxide electrode material has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a titanium dioxide electrode material and a preparation method and application thereof.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention:

[0008] A titanium oxide electrode material is composed of a modified graphene oxide layer, a titanium oxide layer and a modified iron-based metal organic framework material layer from top to bottom.

[0009] Furthermore, the preparation method of the modified graphene oxide comprises the following steps:

[0010] 1) dispersing graphene oxide in ethanol to obtain an ethanol dispersion of graphene oxide, then adding ferric chloride hexahydrate to the ethanol dispersion of graphene oxide, stirring and reacting to obtain iron ion-bridged graphene oxide;

[0011] 2) placing the iron ion-bridged graphene oxide obtained in step 1) in a hydrogen iodide solution with a concentration of 1.15 g / mL for immersion treatment;

[0012] 3) placing the iron ion-bridged graphene oxide after the immersion treatment in step 2) in an acidic solution for immersion modification to obtain the modified graphene oxide.

[0013] Furthermore, in step 1), the mass ratio of the graphene oxide to ferric chloride hexahydrate is 10:(1-3).

[0014] Furthermore, in step 1), the stirring reaction is specifically: controlling the stirring speed to 40 r / min, and stirring the reaction at 120-160° C. for 4-8 hours.

[0015] Furthermore, in step 2), the mass volume ratio of the iron ion-bridged graphene oxide and the hydrogen iodide solution is 1 g:5 mL.

[0016] Furthermore, in step 2), the immersion treatment is specifically: immersion treatment at room temperature for 5 to 15 minutes.

[0017] Furthermore, in step 3), the acidic solution is a 1 mol / L sulfuric acid solution or a 1 mol / L nitric acid solution.

[0018] Furthermore, in step 3), the immersion modification is specifically: immersion modification at 40-60° C. for 2-3 hours.

[0019] Furthermore, the method for preparing titanium dioxide comprises the following steps:

[0020] Titanium dioxide and titanium are mixed, kept warm in an air atmosphere, then calcined in a nitrogen atmosphere, cooled, and ball-milled to obtain titanium dioxide powder with an average particle size of 35 μm, namely the titanium dioxide.

[0021] Furthermore, the mass ratio of titanium dioxide to titanium is (1-3):1.

[0022] Furthermore, the heat preservation is specifically: heat preservation at 1600-1650° C. for 20-40 minutes.

[0023] Furthermore, the calcination is specifically: calcining at 1350-1450° C. for 8-10 hours.

[0024] Furthermore, the preparation method of the modified iron-based metal organic framework material comprises the following steps:

[0025] 1) dissolving diaminoterephthalic acid and ferric chloride hexahydrate in N,N-dimethylformamide and reacting to obtain an iron-based metal organic framework material;

[0026] 2) dispersing the iron-based metal-organic framework material obtained in step 1) in ethanol to obtain an ethanol dispersion of the iron-based metal-organic framework material, then adding a transition metal oxide to the ethanol dispersion of the iron-based metal-organic framework material, and ultrasonically dispersing the mixture to obtain the modified iron-based metal-organic framework material.

[0027] Furthermore, in step 1), the mass ratio of diaminoterephthalic acid to ferric chloride hexahydrate is 1:(1.5-2).

[0028] Furthermore, in step 1), the reaction is specifically: reacting at 140-160° C. for 24-36 hours.

[0029] Furthermore, in step 2), the transition metal oxide is one or more of nickel oxide, manganese dioxide and cobalt oxide.

[0030] Furthermore, in step 2), the mass ratio of the iron-based metal organic framework material to the transition metal oxide is 10:(0.5-1.5).

[0031] The second technical solution of the present invention:

[0032] The method for preparing the above-mentioned titanium dioxide electrode material comprises the following steps:

[0033] 1) placing the modified graphene oxide, titania and modified iron-based metal-organic framework material in a graphite mold according to the layer structure of the modified graphene oxide layer, the titania layer and the modified iron-based metal-organic framework material layer for preforming to obtain a preformed titania electrode material;

[0034] 2) Spark plasma sintering the preformed titanium suboxide electrode material obtained in step 1) to obtain the titanium suboxide electrode material.

[0035] Furthermore, in step 2), the spark plasma sintering is performed at a pressure of 10 to 100 MPa, a temperature of 1000 to 1300° C., and a duration of 5 to 15 minutes.

[0036] The third technical solution of the present invention:

[0037] The above-mentioned titanium dioxide electrode material is used for the removal of COD in wastewater.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The titanium dioxide electrode material provided by the present invention can achieve a COD removal rate of 96.14% in wastewater and has a good COD removal effect in wastewater. DETAILED DESCRIPTION

[0040] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0041] In addition, for numerical ranges in the present invention, it is understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated value or intervening value in the stated range is also included in the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0042] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0043] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0044] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0045] In the following embodiment, a method for preparing a titanium dioxide electrode material comprises the following steps:

[0046] 1. Preparation of modified graphene oxide

[0047] 1) dispersing graphene oxide in ethanol to obtain an ethanol dispersion of graphene oxide, then adding ferric chloride hexahydrate to the ethanol dispersion of graphene oxide according to a mass ratio of graphene oxide to ferric chloride hexahydrate of 10:(1-3), controlling the stirring speed to 40 r / min, stirring at 120-160° C. for 4-8 hours, centrifuging, washing with water, and drying to obtain iron ion-bridged graphene oxide;

[0048] 2) placing the iron-bridged graphene oxide obtained in step 1) in a hydrogen iodide solution with a concentration of 1.15 g / mL according to a mass volume ratio of the iron-bridged graphene oxide to the hydrogen iodide solution of 1 g:5 mL, and immersing the mixture at room temperature for 5 to 15 minutes;

[0049] 3) placing the iron ion-bridged graphene oxide after the immersion treatment in step 2) in an acidic solution, and immersing and modifying it at 40-60° C. for 2-3 hours to obtain the modified graphene oxide;

[0050] Wherein, the acidic solution is a 1 mol / L sulfuric acid solution or a 1 mol / L nitric acid solution;

[0051] 2. Preparation of titanium dioxide

[0052] Titanium dioxide and titanium are mixed in a mass ratio of (1 to 3):1, and the mixture is kept at 1600 to 1650° C. for 20 to 40 minutes in an air atmosphere. The mixture is then calcined at 1350 to 1450° C. for 8 to 10 hours in a nitrogen atmosphere, cooled, and ball-milled to obtain titanium dioxide powder having an average particle size of 35 μm, namely, the titanium dioxide;

[0053] 3. Preparation of modified iron-based metal-organic framework materials

[0054] 1) dissolving diaminoterephthalic acid and ferric chloride hexahydrate in N,N-dimethylformamide at a mass ratio of 1:(1.5-2), reacting at 140-160° C. for 24-36 hours, centrifuging, washing with water, and drying to obtain an iron-based metal-organic framework material;

[0055] 2) dispersing the iron-based metal-organic framework material obtained in step 1) in ethanol to obtain an ethanol dispersion of the iron-based metal-organic framework material, then adding the transition metal oxide to the ethanol dispersion of the iron-based metal-organic framework material at a mass ratio of the iron-based metal-organic framework material to the transition metal oxide of 10:(0.5-1.5), ultrasonically dispersing at 60-80° C. for 30 minutes, centrifuging, washing with water, and drying to obtain the modified iron-based metal-organic framework material;

[0056] Wherein, the transition metal oxide is one or more of nickel oxide, manganese dioxide and cobalt tetroxide;

[0057] 4. Preparation of titanium dioxide electrode materials

[0058] 1) placing the modified graphene oxide prepared in step 1, the titania prepared in step 2, and the modified iron-based metal-organic framework material prepared in step 3 in a graphite mold according to the layer structure of the modified graphene oxide layer, the titania layer, and the modified iron-based metal-organic framework layer, and preforming them under a pressure of 20 MPa to obtain a preformed titania electrode material;

[0059] 2) performing spark plasma sintering on the preformed titanium dioxide electrode material obtained in step 1) in a nitrogen atmosphere to obtain the titanium dioxide electrode material;

[0060] The spark plasma sintering is performed at a pressure of 10 to 100 MPa, a temperature of 1000 to 1300° C., and a duration of 5 to 15 minutes.

[0061] Example 1

[0062] A titanium dioxide electrode material

[0063] 1. Preparation of modified graphene oxide

[0064] 1) dispersing graphene oxide in ethanol to obtain an ethanol dispersion of graphene oxide, then adding ferric chloride hexahydrate to the ethanol dispersion of graphene oxide at a mass ratio of graphene oxide to ferric chloride hexahydrate of 10:1, controlling the stirring speed to 40 r / min, stirring and reacting at 120° C. for 4 hours, centrifuging, washing with water, and drying to obtain iron ion-bridged graphene oxide;

[0065] 2) placing the iron-ion-bridged graphene oxide obtained in step 1) in a 1.15 g / mL hydrogen iodide solution at a mass volume ratio of 1 g to 5 mL, and immersing the solution at room temperature for 5 minutes to reduce the interaction between adjacent graphene oxide nanosheets;

[0066] 3) placing the iron ion-bridged graphene oxide after the immersion treatment in step 2) in an acidic solution, and immersing and modifying it at 40° C. for 2 hours to obtain the modified graphene oxide;

[0067] Wherein, the acidic solution is a sulfuric acid solution with a concentration of 1 mol / L;

[0068] 2. Preparation of titanium dioxide

[0069] Titanium dioxide and titanium are mixed in a mass ratio of 1:1, and the mixture is kept at 1600° C. for 20 minutes in an air atmosphere. The mixture is then calcined at 1350° C. for 8 hours in a nitrogen atmosphere, cooled, and ball-milled to obtain titanium dioxide powder having an average particle size of 35 μm, namely, the titanium dioxide;

[0070] 3. Preparation of modified iron-based metal-organic framework materials

[0071] 1) dissolving diaminoterephthalic acid and ferric chloride hexahydrate in N,N-dimethylformamide at a mass ratio of 1:1.5, reacting at 140° C. for 24 hours, centrifuging, washing with water, and drying to obtain an iron-based metal-organic framework material;

[0072] 2) dispersing the iron-based metal-organic framework material obtained in step 1) in ethanol to obtain an ethanol dispersion of the iron-based metal-organic framework material, then adding the transition metal oxide to the ethanol dispersion of the iron-based metal-organic framework material at a mass ratio of 10:0.5, ultrasonically dispersing the mixture at 60° C. for 30 minutes, centrifuging, washing with water, and drying to obtain the modified iron-based metal-organic framework material;

[0073] Wherein, the transition metal oxide is nickel oxide;

[0074] 4. Preparation of titanium dioxide electrode materials

[0075] 1) placing the modified graphene oxide prepared in step 1, the titania prepared in step 2, and the modified iron-based metal-organic framework material prepared in step 3 in a graphite mold according to the layer structure of the modified graphene oxide layer, the titania layer, and the modified iron-based metal-organic framework layer, and preforming them under a pressure of 20 MPa to obtain a preformed titania electrode material;

[0076] 2) performing spark plasma sintering on the preformed titanium dioxide electrode material obtained in step 1) in a nitrogen atmosphere to obtain the titanium dioxide electrode material;

[0077] The spark plasma sintering process is performed at a pressure of 10 MPa, a temperature of 1000° C., and a duration of 5 minutes.

[0078] Example 2

[0079] A titanium dioxide electrode material

[0080] 1. Preparation of modified graphene oxide

[0081] 1) dispersing graphene oxide in ethanol to obtain an ethanol dispersion of graphene oxide, then adding ferric chloride hexahydrate to the ethanol dispersion of graphene oxide in a mass ratio of graphene oxide to ferric chloride hexahydrate of 10:2, controlling the stirring speed to 40 r / min, stirring at 140° C. for 6 h, centrifuging, washing with water, and drying to obtain iron ion-bridged graphene oxide;

[0082] 2) placing the iron-ion-bridged graphene oxide obtained in step 1) in a 1.15 g / mL hydrogen iodide solution at a mass volume ratio of 1 g to 5 mL, and immersing the solution at room temperature for 10 minutes to reduce the interaction between adjacent graphene oxide nanosheets;

[0083] 3) placing the iron ion-bridged graphene oxide after the immersion treatment in step 2) in an acidic solution, and immersing and modifying it at 50° C. for 2.5 hours to obtain the modified graphene oxide;

[0084] Wherein, the acidic solution is a sulfuric acid solution with a concentration of 1 mol / L;

[0085] 2. Preparation of titanium dioxide

[0086] Titanium dioxide and titanium are mixed in a mass ratio of 2:1, and the mixture is kept at 1625° C. for 30 minutes in an air atmosphere, and then calcined at 1400° C. for 9 hours in a nitrogen atmosphere, cooled, and ball-milled to obtain titanium dioxide powder with an average particle size of 35 μm, namely, the titanium dioxide;

[0087] 3. Preparation of modified iron-based metal-organic framework materials

[0088] 1) dissolving diaminoterephthalic acid and ferric chloride hexahydrate in N,N-dimethylformamide at a mass ratio of 1:1.6, reacting at 150° C. for 30 hours, centrifuging, washing with water, and drying to obtain an iron-based metal-organic framework material;

[0089] 2) dispersing the iron-based metal-organic framework material obtained in step 1) in ethanol to obtain an ethanol dispersion of the iron-based metal-organic framework material, then adding the transition metal oxide to the ethanol dispersion of the iron-based metal-organic framework material at a mass ratio of 10:1 between the iron-based metal-organic framework material and the transition metal oxide, ultrasonically dispersing the mixture at 70° C. for 30 minutes, centrifuging, washing with water, and drying to obtain the modified iron-based metal-organic framework material;

[0090] Wherein, the transition metal oxide is manganese dioxide;

[0091] 4. Preparation of titanium dioxide electrode materials

[0092] 1) placing the modified graphene oxide prepared in step 1, the titania prepared in step 2, and the modified iron-based metal-organic framework material prepared in step 3 in a graphite mold according to the layer structure of the modified graphene oxide layer, the titania layer, and the modified iron-based metal-organic framework layer, and preforming them under a pressure of 20 MPa to obtain a preformed titania electrode material;

[0093] 2) performing spark plasma sintering on the preformed titanium dioxide electrode material obtained in step 1) in a nitrogen atmosphere to obtain the titanium dioxide electrode material;

[0094] The spark plasma sintering process is performed at a pressure of 30 MPa, a temperature of 1150° C., and a duration of 10 minutes.

[0095] Example 3

[0096] A titanium dioxide electrode material

[0097] 1. Preparation of modified graphene oxide

[0098] 1) dispersing graphene oxide in ethanol to obtain an ethanol dispersion of graphene oxide, then adding ferric chloride hexahydrate to the ethanol dispersion of graphene oxide in a mass ratio of graphene oxide to ferric chloride hexahydrate of 10:3, controlling the stirring speed to 40 r / min, stirring and reacting at 160° C. for 8 h, centrifuging, washing with water, and drying to obtain iron ion-bridged graphene oxide;

[0099] 2) placing the iron-ion-bridged graphene oxide obtained in step 1) in a 1.15 g / mL hydrogen iodide solution at a mass volume ratio of 1 g to 5 mL, and immersing the solution at room temperature for 15 minutes to reduce the interaction between adjacent graphene oxide nanosheets;

[0100] 3) placing the iron ion-bridged graphene oxide after the immersion treatment in step 2) in an acidic solution, and immersing and modifying it at 60° C. for 3 hours to obtain the modified graphene oxide;

[0101] Wherein, the acidic solution is a nitric acid solution with a concentration of 1 mol / L;

[0102] 2. Preparation of titanium dioxide

[0103] Titanium dioxide and titanium are mixed in a mass ratio of 3:1, and the mixture is kept at 1650° C. for 40 minutes in an air atmosphere, and then calcined at 1450° C. for 10 hours in a nitrogen atmosphere, cooled, and ball-milled to obtain titanium dioxide powder with an average particle size of 35 μm, namely, the titanium dioxide;

[0104] 3. Preparation of modified iron-based metal-organic framework materials

[0105] 1) dissolving diaminoterephthalic acid and ferric chloride hexahydrate in N,N-dimethylformamide at a mass ratio of 1:2, reacting at 160° C. for 36 hours, centrifuging, washing with water, and drying to obtain an iron-based metal-organic framework material;

[0106] 2) dispersing the iron-based metal-organic framework material obtained in step 1) in ethanol to obtain an ethanol dispersion of the iron-based metal-organic framework material, then adding the transition metal oxide to the ethanol dispersion of the iron-based metal-organic framework material at a mass ratio of 10:1.5, ultrasonically dispersing the mixture at 80° C. for 30 minutes, centrifuging, washing with water, and drying to obtain the modified iron-based metal-organic framework material;

[0107] Wherein, the transition metal oxide is cobalt tetroxide;

[0108] 4. Preparation of titanium dioxide electrode materials

[0109] 1) placing the modified graphene oxide prepared in step 1, the titania prepared in step 2, and the modified iron-based metal-organic framework material prepared in step 3 in a graphite mold according to the layer structure of the modified graphene oxide layer, the titania layer, and the modified iron-based metal-organic framework layer, and preforming them under a pressure of 20 MPa to obtain a preformed titania electrode material;

[0110] 2) performing spark plasma sintering on the preformed titanium dioxide electrode material obtained in step 1) in a nitrogen atmosphere to obtain the titanium dioxide electrode material;

[0111] The spark plasma sintering process is carried out at a pressure of 100 MPa, a temperature of 1300° C., and a duration of 15 minutes.

[0112] Example 4

[0113] A titanium dioxide electrode material

[0114] The same as Example 2, except that, in the preparation process of the modified iron-based metal organic framework material in step 3, the transition metal oxide is prepared by mixing nickel oxide and manganese dioxide in a mass ratio of 1:1.

[0115] Example 5

[0116] A titanium dioxide electrode material

[0117] The same as Example 2, except that, in the preparation process of the modified iron-based metal organic framework material in step 3, the transition metal oxide is prepared by mixing manganese dioxide and cobalt trioxide in a mass ratio of 1:1.

[0118] Example 6

[0119] A titanium dioxide electrode material

[0120] The same as Example 2, except that, in the preparation process of the modified iron-based metal organic framework material in step 3, the transition metal oxide is prepared by mixing nickel oxide and cobalt trioxide in a mass ratio of 1:1.

[0121] Example 7

[0122] A titanium dioxide electrode material

[0123] The same as Example 2, except that, in the preparation process of the modified iron-based metal organic framework material in step 3, the transition metal oxide is prepared by mixing nickel oxide, manganese dioxide and cobalt trioxide in a mass ratio of 1:1:1.

[0124] Comparative Example 1

[0125] A titanium dioxide electrode material

[0126] Same as Example 6, except that the preparation of modified graphene oxide in step 1 is:

[0127] 1) dispersing graphene oxide in ethanol to obtain an ethanol dispersion of graphene oxide, then adding ferric chloride hexahydrate to the ethanol dispersion of graphene oxide in a mass ratio of graphene oxide to ferric chloride hexahydrate of 10:2, controlling the stirring speed to 40 r / min, stirring at 140° C. for 6 h, centrifuging, washing with water, and drying to obtain iron ion-bridged graphene oxide;

[0128] 2) placing the iron ion-bridged graphene oxide obtained in step 1) in an acidic solution, and immersing and modifying it at 50° C. for 2.5 hours to obtain the modified graphene oxide;

[0129] Wherein, the acidic solution is a sulfuric acid solution with a concentration of 1 mol / L.

[0130] Comparative Example 2

[0131] A titanium dioxide electrode material

[0132] Same as Example 6, except that the preparation of modified graphene oxide in step 1 is:

[0133] placing the graphene oxide in an acidic solution, and immersing and modifying the graphene oxide at 50° C. for 2.5 hours to obtain the modified graphene oxide;

[0134] Wherein, the acidic solution is a sulfuric acid solution with a concentration of 1 mol / L.

[0135] Comparative Example 3

[0136] A titanium dioxide electrode material

[0137] Same as Example 6, except that the preparation of modified graphene oxide in step 1 is:

[0138] 1) dispersing graphene oxide in ethanol to obtain an ethanol dispersion of graphene oxide, then adding ferric chloride hexahydrate to the ethanol dispersion of graphene oxide in a mass ratio of graphene oxide to ferric chloride hexahydrate of 10:2, controlling the stirring speed to 40 r / min, stirring at 140° C. for 6 h, centrifuging, washing with water, and drying to obtain iron ion-bridged graphene oxide;

[0139] 2) According to the mass volume ratio of the iron ion-bridged graphene oxide and the hydrogen iodide solution of 1 g: 5 mL, the iron ion-bridged graphene oxide obtained in step 1) is placed in a hydrogen iodide solution with a concentration of 1.15 g / mL, and immersed at room temperature for 10 minutes to obtain the modified graphene oxide.

[0140] Comparative Example 4

[0141] A titanium dioxide electrode material

[0142] Same as Example 6, except that the preparation of titanium dioxide in step 2 is as follows:

[0143] Titanium dioxide was kept at 1625° C. for 30 minutes in an air atmosphere, then calcined at 1400° C. for 9 hours in a nitrogen atmosphere, cooled, and ball-milled to obtain titanium dioxide powder with an average particle size of 35 μm, namely the titanium dioxide.

[0144] Comparative Example 5

[0145] A titanium dioxide electrode material

[0146] Same as Example 6, except that the preparation of titanium dioxide in step 2 is as follows:

[0147] Titanium dioxide and titanium were mixed in a mass ratio of 2:1, calcined at 1400° C. for 9 hours in a nitrogen atmosphere, cooled, and ball-milled to obtain titanium dioxide powder with an average particle size of 35 μm, namely the titanium dioxide.

[0148] Comparative Example 6

[0149] A titanium dioxide electrode material

[0150] The same as Example 6, except that the modification of the iron-based metal organic framework material in step 3 is omitted, and in step 4, the titanium dioxide electrode material is prepared using the iron-based metal organic framework material as a raw material.

[0151] Effect verification

[0152] Titanium dioxide electrode material was used as anode and graphite as cathode, and the current density was controlled at 25 mA / cm 2 , the electrode spacing is 2.0 cm, 2.5L of COD-containing wastewater is electrolyzed, the electrolysis time is controlled to 2h, the COD content in the wastewater after electrolysis is detected, and the COD removal rate is calculated; the test results are shown in Table 1;

[0153] Table 1 Test results

[0154]

[0155] It can be seen from the data in Table 1 that the titanium dioxide electrode material provided by the present invention can achieve a COD removal rate of 96.14% in wastewater, and has a good removal effect on COD in wastewater.

[0156] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A titanium dioxide electrode material, characterized in that: The titanium dioxide electrode material is composed of a modified graphene oxide layer, a titanium dioxide layer and a modified iron-based metal organic framework material layer in sequence from top to bottom.

2. The titanium dioxide electrode material according to claim 1, characterized in that: The preparation method of the modified graphene oxide comprises the following steps: 1) dispersing graphene oxide in ethanol to obtain an ethanol dispersion of graphene oxide, then adding ferric chloride hexahydrate to the ethanol dispersion of graphene oxide, stirring and reacting to obtain iron ion-bridged graphene oxide; 2) placing the iron ion-bridged graphene oxide obtained in step 1) in a hydrogen iodide solution with a concentration of 1.15 g / mL for immersion treatment; 3) placing the iron ion-bridged graphene oxide after the immersion treatment in step 2) in an acidic solution for immersion modification to obtain the modified graphene oxide.

3. A titanium dioxide electrode material according to claim 2, characterized in that: In step 1), the mass ratio of graphene oxide to ferric chloride hexahydrate is 10:(1-3); the stirring reaction is specifically: controlling the stirring speed to 40 r / min, and stirring the reaction at 120-160° C. for 4-8 hours; In step 2), the mass volume ratio of the iron ion-bridged graphene oxide and the hydrogen iodide solution is 1 g: 5 mL; the immersion treatment is specifically: immersion treatment at room temperature for 5 to 15 minutes; In step 3), the acidic solution is a 1 mol / L sulfuric acid solution or a 1 mol / L nitric acid solution; and the immersion modification is specifically: immersion modification at 40-60° C. for 2-3 hours.

4. The titanium dioxide electrode material according to claim 1, characterized in that: The method for preparing titanium dioxide comprises the following steps: Titanium dioxide and titanium are mixed, kept warm in an air atmosphere, then calcined in a nitrogen atmosphere, cooled, and ball-milled to obtain titanium dioxide powder with an average particle size of 35 μm, namely the titanium dioxide.

5. The titanium dioxide electrode material according to claim 4, characterized in that: The mass ratio of titanium dioxide to titanium is (1-3):1; the heat preservation is specifically: heat preservation at 1600-1650°C for 20-40 minutes; the calcination is specifically: calcination at 1350-1450°C for 8-10 hours.

6. The titanium dioxide electrode material according to claim 1, characterized in that: The preparation method of the modified iron-based metal organic framework material comprises the following steps: 1) dissolving diaminoterephthalic acid and ferric chloride hexahydrate in N,N-dimethylformamide and reacting to obtain an iron-based metal organic framework material; 2) dispersing the iron-based metal-organic framework material obtained in step 1) in ethanol to obtain an ethanol dispersion of the iron-based metal-organic framework material, then adding a transition metal oxide to the ethanol dispersion of the iron-based metal-organic framework material, and ultrasonically dispersing the mixture to obtain the modified iron-based metal-organic framework material.

7. The titanium dioxide electrode material according to claim 6, characterized in that: In step 1), the mass ratio of diaminoterephthalic acid to ferric chloride hexahydrate is 1:(1.5-2); in step 1), the reaction is specifically: reacting at 140-160° C. for 24-36 hours. In step 2), the transition metal oxide is one or more of nickel oxide, manganese dioxide and cobalt trioxide; in step 2), the mass ratio of the iron-based metal organic framework material to the transition metal oxide is 10:(0.5-1.5).

8. A method for preparing the titanium dioxide electrode material according to any one of claims 1 to 7, characterized in that: The following steps are involved: 1) placing the modified graphene oxide, titania and modified iron-based metal-organic framework material in a graphite mold according to the layer structure of the modified graphene oxide layer, the titania layer and the modified iron-based metal-organic framework material layer for preforming to obtain a preformed titania electrode material; 2) Spark plasma sintering the preformed titanium suboxide electrode material obtained in step 1) to obtain the titanium suboxide electrode material.

9. The preparation method according to claim 8, characterized in that In step 2), the spark plasma sintering is performed at a pressure of 10 to 100 MPa, a temperature of 1000 to 1300° C., and a duration of 5 to 15 minutes.

10. Use of the titanium dioxide electrode material according to any one of claims 1 to 7 in removing COD from wastewater.

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