Electrode material for electrochemical bromine extraction, method and device for electrochemical bromine extraction and application thereof

Abstract

The present invention discloses an electrode for electrochemical bromine extraction, a preparation method, and its application. The electrode, based on titanium-based cobalt oxide, extracts bromine from liquids. It is particularly suitable for selectively extracting bromine from various bromine-containing chemical wastewaters, exhibiting high catalytic activity and a high bromine recovery rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of treatment of bromine-containing wastewater and relates to an electrode for electrochemical bromine extraction, a preparation method, a device and applications thereof. Background Art

[0002] Bromine is a key chemical raw material, a precious and rare element, and a non-renewable resource. The diverse range of inorganic bromides, bromates, and bromine-containing organic compounds derived from it have made significant contributions to the national economy and technological development. In response to the needs of industry and daily life, researchers have discovered that adding bromine and its derivatives (such as bromine chloride, hydrobromic acid, and bromopyridine) to chemical reactions can improve reaction efficiency and increase product purity. Aromatic organic bromides are widely used in pharmaceuticals, pesticides, dyes, etc. However, when aromatic organic bromides are prepared by bromination reaction, the utilization rate of bromine is only 50-70%, so chemical industrial wastewater containing bromide ions and bromide-containing by-products (such as hydrobromic acid, sodium bromide, potassium bromide, etc.) will be produced. In addition, this type of wastewater usually contains excessive (organic, inorganic) raw materials, reaction intermediates, acids and alkalis, ammonia nitrogen, by-product (single / multiple) component inorganic salts and residual dissolved products. It is a complex high-salt, toxic and harmful industrial wastewater. If this type of wastewater is treated as waste liquid, waste salt, or residue after evaporation and concentration, not only will the disposal cost be high, it will be a difficult point in the treatment of hazardous waste in the industry and it will also be a waste of resources. If the Br contained in the wastewater is - Extracting and generating reusable Br2 can not only reduce environmental pollution, but also is an effective route to achieve Br2 recycling and reuse, reducing resource waste.

[0003] However, the actual bromine-containing chemical wastewater from petrochemical, pharmaceutical, pesticide, rubber and other industries is characterized by mixed wastewater with high salt, high COD and high ammonia nitrogen. The composition is complex and toxic. Various substances have the characteristics of mixing, azeotropy and commonality, which restrict each other. In order to break through these constraints and separate and extract bromine from it and achieve a certain purity, the technical difficulty and process are relatively large. At present, the chlorine oxidation air blowing method is often used for industrial bromine-containing wastewater. Similar to the extraction of bromine from brine, the acidified bromine-containing wastewater is chlorine-oxidized, and the Br in the brine is oxidized. - The bromine is then blown out of the bromine-containing wastewater using air and absorbed by sulfur dioxide and water to produce a finished absorption solution. This finished solution is oxidized by chlorine and simultaneously subjected to steam distillation to remove the Br2. The bromine is condensed to produce crude bromine, which is then purified and separated after chlorine removal to produce finished industrial bromine. This advanced bromine production process offers high bromine utilization, and the resulting waste acid can be reused to acidify brine. However, its disadvantages are that it is significantly affected by temperature, has high hazardous waste treatment costs, and has high equipment operating costs. Furthermore, this method can precipitate other salts, resulting in low purity of the finished bromine.

[0004] Existing bromine extraction methods include resin adsorption, gas membrane extraction, and solvent extraction. However, these methods often face challenges in effectively extracting high-purity bromine from wastewater due to high resin requirements, limited ability to treat low-concentration bromine-containing wastewater, and volatile extractants that make bromine difficult to separate. Therefore, considering the current imbalance between domestic bromine supply and demand and my country's current development status, it is imperative to develop cost-effective and environmentally friendly bromine recovery technologies.

[0005] Currently, there are several studies on electrochemical bromine extraction from bromine-containing wastewater, primarily using graphite electrodes and Ti / RuO2 electrodes. For example, Sun Mei et al., as described in Non-Patent Literature 1, conducted a series of studies on electrochemical bromine extraction using graphite as the working electrode (anode).

[0006] For example, Patent Document 1 discloses a method for oxidizing ionic bromine to generate elemental bromine by electrolysis, wherein graphite, titanium (Ti), ruthenium (Ru) or platinum (Pt) noble metal is used as the working electrode, and a direct current is passed to make Br - Converted into Br2, and recovered using an extractant.

[0007] For example, Patent Document 2 also discloses a method for separating bromine in liquid by electrochemistry, which uses ruthenium (Ru), lead (Pb), tin (Sn), antimony (Sb), and titanium (Ti) as working electrodes, and is used for separating bromine in liquid by electrochemical methods. - The Br content is directly electrochemically treated at the - Oxidation to Br2 can achieve high bromine removal efficiency in liquids.

[0008] However, the above disclosed electrochemical bromine extraction method does not take into account and cannot cope with the influence of a large number of interfering components contained in actual wastewater. For example, the wastewater produced by the bromination process usually contains a large amount of organic matter, ammonia nitrogen, chloride ions, and many interfering ions. These interfering ions are not suitable for electrochemical oxidation of Br. - In the process, we will work with Br - The oxidation of Br - Based on this, it is actually difficult for traditional electrodes to effectively extract bromine resources from bromine-containing wastewater and achieve effective recovery of bromine resources.

[0009] Therefore, there is an urgent need for practical and feasible technologies and devices that reduce difficulty, simplify operation, and reduce running costs. Furthermore, in the electrochemical bromine extraction process, improving the selective extraction of bromine from wastewater has greater application value and practical significance.

[0010] Non-patent literature 1: Sun M, Lowry GV, Gregory K B. Selective oxidation of bromide in wastewater brines from hydraulic fracturing[J]. Water Research, 2013, 47(11): 3723-3731.

[0011] Patent Document 1: Publication No. CN109371416 A, a method for recovering bromine from bromine-containing wastewater;

[0012] Patent document 2: Publication No. CN114956264 A, a method for separating bromine in liquid using electrochemistry. Summary of the Invention

[0013] 1. Problem to be solved

[0014] Based on the problem of unsatisfactory selective extraction of bromine in the existing electrochemical bromine extraction process, the purpose of the present invention is to provide an electrode material for electrochemical bromine extraction.

[0015] At the same time, the present invention also provides:

[0016] Method for preparing electrode materials for electrochemical bromine extraction;

[0017] Method for extracting bromine from liquids;

[0018] Plants for extracting bromine from liquids;

[0019] The electrode, extraction method, or extraction device provided for the purpose of the present invention has practical and feasible application value.

[0020] 2. Technical solution

[0021] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0022] A first aspect of the present invention provides an electrode material for electrochemically treating a liquid to extract bromine;

[0023] The electrode material includes:

[0024] a substrate comprising titanium, and cobalt oxide disposed on the substrate;

[0025] Wherein, electron paramagnetic resonance detection shows that the cobalt oxide has oxygen vacancies (hereinafter abbreviated as Ov).

[0026] According to any embodiment of the first aspect of the present invention, the cobalt oxide has characteristic peaks at the following diffraction angles 2θ (±0.2°): 19.0°, 31.4°, and 36.9° in its powder X-ray diffraction peaks;

[0027] According to any embodiment of the first aspect of the present invention, the cobalt oxide has a powder X-ray diffraction peak of

[0028] The characteristic peak at 2θ (±0.2°) = 19.0° corresponds to the (111) crystal plane of cobalt oxide;

[0029] The characteristic peak at 2θ (±0.2°) = 31.4° corresponds to the (220) crystal plane of cobalt oxide;

[0030] The characteristic peak at 2θ (±0.2°) = 36.9° corresponds to the (311) crystal plane of cobalt oxide.

[0031] According to any embodiment of the first aspect of the present invention, the cobalt oxide is tricobalt tetroxide.

[0032] A second aspect of the present invention provides a method for preparing an electrode material for electrochemical bromine extraction, comprising:

[0033] preparing a precursor electrode, the precursor electrode comprising a substrate containing titanium, and cobalt oxide on the substrate;

[0034] The precursor electrode is treated with sodium borohydride and / or potassium borohydride to obtain the electrode.

[0035] According to any embodiment of the second aspect of the present invention, the sodium borohydride and / or potassium borohydride is configured into a solution with a concentration of 0.025-0.050 mol / L; and the treatment time is 15-30 min.

[0036] According to any embodiment of the second aspect of the present invention, the method for preparing an electrode material for electrochemical bromine extraction comprises the following steps:

[0037] Prepare solution a: the solution a contains a cobalt source and urea;

[0038] And the following steps (A) to (C):

[0039] (A) contacting a titanium-containing substrate with the solution a and performing a high-temperature treatment in a sealed state to obtain a product A;

[0040] (B) subjecting the product A to a high-temperature calcination treatment to obtain a product B;

[0041] (C) treating the product B with sodium borohydride and / or potassium borohydride to obtain the electrode.

[0042] According to any embodiment of the second aspect of the present invention,

[0043] According to the area of ​​the titanium substrate is 6cm 2 calculate:

[0044] Calculated based on the concentration of cobalt, the concentration of the cobalt source added to the solution a is 3mM to 60mM, preferably 5mM to 50mM;

[0045] In the solution a, the concentration of urea added is 15-300 mM, preferably 25-250 mM.

[0046] According to any embodiment of the second aspect of the present invention, in step (A), the treatment temperature is 90-150° C.;

[0047] The treatment time is 5-8 hours.

[0048] According to any embodiment of the second aspect of the present invention, in step (B),

[0049] The treatment temperature is 300-500°C;

[0050] The treatment time is 2-3 hours.

[0051] According to any embodiment of the second aspect of the present invention, in step (C), the sodium borohydride and / or potassium borohydride is prepared into a solution with a concentration of 0.025-0.050 mol / L;

[0052] The processing time is 15-30 minutes.

[0053] According to any embodiment of the second aspect of the present invention,

[0054] If the solution a contains a cobalt source, urea and ammonium fluoride; the area of ​​the substrate containing titanium is 6cm 2 calculate:

[0055] Calculated based on the concentration of cobalt, the concentration of the cobalt source added to the solution a is 3mM to 60mM, preferably 5mM to 50mM;

[0056] In the solution a, the concentration of urea added is 15-300 mM, preferably 25-250 mM;

[0057] In the solution a, the concentration of ammonium fluoride added is 6-120 mM, preferably 10-100 mM;

[0058] According to any embodiment of the second aspect of the present invention,

[0059] If the solution a contains a cobalt source and urea, but does not contain ammonium fluoride; the area of ​​the substrate containing titanium is 6cm 2 calculate:

[0060] Calculated based on the concentration of cobalt, the concentration of the cobalt source added to the solution a is 30mM to 50mM, preferably 40mM to 50mM;

[0061] In the solution a, the concentration of urea added is 150-250 mM, preferably 200-250 mM.

[0062] The third aspect of the present invention provides a method for extracting bromine from a liquid, wherein the liquid is electrochemically treated to generate Br - The conversion process to Br2;

[0063] Wherein, during the electrochemical treatment:

[0064] An electrode material according to any embodiment of the first aspect of the present invention, or an electrode material prepared by the method according to any embodiment of the second aspect of the present invention is used as an anode;

[0065] The current density was set to 0.5-5 mA / cm 2 .

[0066] According to any embodiment of the third aspect of the present invention, the bromine-containing liquid has a pH value in the range of 3-7; preferably a pH value of 3-5; or

[0067] The pH value of the bromine-containing liquid after adjustment is in the range of 3-7, preferably 3-5.

[0068] According to any embodiment of the third aspect of the present invention, the method for extracting bromine from a liquid further comprises the following steps: performing stripping treatment using a gas to collect Br2 formed by the electrochemical treatment.

[0069] According to any embodiment of the third aspect of the present invention, the bromine-containing liquid comprises high hardness bromine-containing wastewater (containing Ca 2+ Mg 2+ ), any one or more complex water qualities produced in chemical production processes, such as high ammonia nitrogen bromine-containing wastewater, high chlorine bromine-containing wastewater, and high organic matter bromine-containing wastewater.

[0070] A fourth aspect of the present invention provides a device for extracting bromine from a liquid, comprising an electrochemical treatment unit;

[0071] The electrochemical treatment unit includes electrodes and a reactor;

[0072] The reactor comprises a chamber 1 and a chamber 2, wherein the chamber 1 and the chamber 2 are separated by an ion-selective permeable membrane;

[0073] The chamber 1 is used to accommodate the liquid containing bromine and to be treated;

[0074] The second chamber is used to fill the electrolyte;

[0075] The electrodes include an anode and a cathode; the anode is placed in chamber one, and the cathode is placed in chamber two;

[0076] Wherein, the anode comprises the electrode material described in any embodiment of the first aspect, or the electrode material prepared by the method described in any embodiment of the second aspect.

[0077] According to any embodiment of the fourth aspect of the present invention, the device for extracting bromine from liquid further comprises a blowing unit;

[0078] The blowing unit is communicated with the chamber one and is used for ventilating the chamber one.

[0079] According to any embodiment of the fourth aspect of the present invention, the device for extracting bromine from liquid further comprises a recovery unit;

[0080] The recovery unit is communicated with the first chamber and is used for receiving the gas exhausted from the first chamber.

[0081] A fifth aspect of the present invention provides a method for extracting bromine from a liquid using the extraction device provided in any embodiment of the first aspect of the present invention, comprising the following steps:

[0082] Step S1:

[0083] introducing bromine-containing liquid into the first chamber;

[0084] introducing electrolyte into the second chamber;

[0085] Step S2:

[0086] Power is supplied to perform electrochemical treatment on the bromine-containing liquid in the first chamber.

[0087] According to any embodiment of the fifth aspect of the present invention, in S1, the initial pH value of the desired liquid is maintained in the range of 3-7, preferably 3-5;

[0088] Preferably, the chloride ion content in the liquid does not exceed 10000 mg / L;

[0089] Maintaining the desired initial pH value of the electrolyte in the range of 3-7, preferably 3-5;

[0090] In S2, during the electrochemical treatment, the current density is set to 0.5-5 mA / cm 2 , preferably 0.5-3 mA / cm 2 .

[0091] According to any embodiment of the fifth aspect of the present invention, step S2 further comprises:

[0092] Ventilation is performed to blow out the bromine obtained through electrochemical treatment in the chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Figure 1 A schematic structural diagram of a H-type double-chamber electrolytic cell reaction device, a specific form of a bromine electrochemical extraction device provided by the present invention;

[0094] Figure 2 Degradation of Br by several common anodes and the electrode materials of the present invention - Experimental effect diagram;

[0095] Figure 3 Cl - Effect of concentration on the degradation of Br by titanium-based oxygen vacancy cobalt tetroxide nanoneedle electrodes - Influence diagram of

[0096] Figure 4 Degradation of Br by different morphologies of titanium-based cobalt tetroxide nanoelectrodes and their oxygen vacancy structures - picture;

[0097] Figure 5 Br for treating actual wastewater using several common anodes and the electrode materials of the present invention - Degradation rate, Br2 generation rate, Cl - Degradation rate, TOC and COD removal rate graph;

[0098] Figure 6 O v - Current efficiency and specific energy consumption of Co3O4 NNs / Ti anode in treating actual wastewater;

[0099] Figure 7 O v -Co3O4 NNs / Ti anode cycling experiment electrochemical oxidation degradation of Br - picture;

[0100] Figure 8 Co3O4 NNs / Ti, O v -X-ray diffraction pattern of Co3O4 NNs / Ti electrode material;

[0101] Figure 9 O v-10μm SEM image of Co3O4 NNs / Ti electrode material;

[0102] Figure 10 O v -500nm SEM image of Co3O4 NNs / Ti electrode material;

[0103] Figure 11 Co3O4 NNs / Ti, O v -X-ray photoelectron full spectrum scanning of Co3O4 NNs / Ti electrode material;

[0104] Figure 12 Co3O4 NNs / Ti, O v -Electron paramagnetic resonance (EPR) spectrum of Co3O4 NNs / Ti electrode material. DETAILED DESCRIPTION

[0105] The present disclosure may be more readily understood by reference to the following description in conjunction with the accompanying drawings and examples, all of which constitute a part of this disclosure. It should be understood that the present disclosure is not limited to the specific products, methods, conditions, or parameters described and / or illustrated herein. Further, the terms used herein are for the purpose of describing specific embodiments by way of example only and are not intended to be limiting unless otherwise indicated.

[0106] It should also be understood that, for the sake of clarity, certain features of the present disclosure may be described herein in the context of separate embodiments, but may also be provided in combination with each other in a single embodiment. That is, unless clearly incompatible or specifically not included, each separate embodiment is considered to be combinable with any other embodiment, and the combination is considered to represent another different embodiment. Conversely, for the sake of simplicity, various features of the present disclosure described in the context of a single embodiment may also be provided individually or in any sub-combination. Finally, although a particular embodiment may be described as part of a series of steps or part of a more general structure, each step or sub-structure itself may also be considered to be an independent embodiment.

[0107] Unless otherwise indicated, it should be understood that each individual element in a list and each combination of individual elements in that list will be interpreted as a different embodiment. For example, a list of embodiments expressed as "A, B, or C" should be interpreted to include embodiments "A," "B," "C," "A or B," "A or C," "B or C," or "A, B, or C."

[0108] In this disclosure, the singular forms of the articles "a," "an," and "the" also include the corresponding plural reference, and a reference to a specific value includes at least that specific value unless the context clearly dictates otherwise. Thus, for example, a reference to "a substance" is a reference to at least one of that substance and equivalents thereof.

[0109] Terms including ordinal numbers such as "first" and "second" may be used to explain various components or fluids, but these components and fluids are not limited by these terms. Therefore, without departing from the teachings of the present disclosure, these terms are only used to distinguish the component / fluid from another component / fluid.

[0110] When items are described by using the conjunction terms "... and / or..." etc., the description should be understood to include any one and all combinations of one or more of the associated listed items.

[0111] In general, the use of the term "about" indicates an approximate value that can vary depending on the desired properties obtained by the disclosed subject matter and will be interpreted in a context-dependent manner based on function. Therefore, one of ordinary skill in the art will be able to interpret a certain degree of difference on a case-by-case basis. In some cases, the number of important figures used when expressing a particular value can be a representative technique for determining the difference allowed by the term "about". In other cases, a gradient in a range of values ​​can be used to determine the range of differences allowed by the term "about". Further, all ranges in this disclosure are inclusive and combinable, and reference to a value stated in a range includes every value within that range.

[0112] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs; and the terms used herein include any and all combinations of one or more of the associated listed items.

[0113] 【1】Used for electrochemical treatment of liquid to extract bromine precursor electrode (Co x O y / Ti) manufacturing method The preparation method comprises: a step of preparing solution a, and the following steps (A) to (B):

[0114] (A) contacting a titanium-containing substrate with the solution a and performing a high-temperature treatment in a sealed state to obtain a product A;

[0115] (B) subjecting the product A to high-temperature calcination to obtain product B.

[0116] Procedure for preparing solution a:

[0117] The solution a contains a cobalt source; or, the solution a contains a cobalt source and urea;

[0118] According to the area of ​​the titanium substrate is 6cm 2 calculate:

[0119] The cobalt source should be added at a concentration of 0.4 mM to 5 mM. Examples of the cobalt source used in the present invention include cobalt nitrate, cobalt chloride, cobalt sulfate, cobalt acetate, and cobalt carbonate.

[0120] As for the said urea, its added concentration should meet the requirement of 25-250mM.

[0121] As the solution a, the types of components and the content of each component will have a significant effect on the morphology of the formed cobalt oxide. The general principle for reference is that the area of ​​the titanium substrate is 6 cm 2 calculate::

[0122] If the solution a contains 3mM to 5mM cobalt nitrate, 15mM to 25mM urea, and 6mM to 10mM NH4F, it is more conducive to the formation of linear cobalt oxide (hereinafter referred to as: Co x O y NWs);

[0123] If the solution a contains 15mM to 25mM cobalt nitrate, 75mM to 125mM urea, and 30mM to 50mM NH4F, it is more conducive to the formation of needle-shaped cobalt oxide (hereinafter referred to as: Co x O y NNs);

[0124] If the solution a contains 30mM to 50mM cobalt nitrate, 150mM to 250mM urea, and 60mM to 100mM NH4F, it is more conducive to the formation of leaf-shaped cobalt oxide (hereinafter referred to as: Co x O y NLs);

[0125] If the solution a contains 30mM to 50mM cobalt nitrate and 150mM to 250mM urea, but does not contain NH4F, it is more conducive to the formation of plate-like cobalt oxide (hereinafter referred to as: Co x O y NPs).

[0126] Step (A): contacting a titanium-containing substrate with the solution a and subjecting it to high-temperature treatment in a sealed state to obtain To product A

[0127] The titanium-containing substrate should contain at least 95% by weight of titanium. Theoretically, the higher the titanium content, the better. Therefore, a high-purity titanium plate is optimal. Furthermore, the titanium-containing substrate should have a surface that is as smooth and clean as possible. For example, the surface can be polished with sandpaper of at least 200 grit, such as 500 grit, and then rinsed several times with alcohol and then deionized (DI) water, followed by drying.

[0128] The method of "performing a high-temperature treatment in a sealed state" is not particularly limited as long as a reaction environment having a certain temperature and pressure can be provided, and a conventionally known method can be used.

[0129] For example, the solution a and the substrate are placed in an autoclave, etc., and the autoclave is then sealed and transferred to a vacuum drying oven for hydrothermal treatment.

[0130] At this time, the high temperature treatment requires the treatment temperature to be 90-150°C; on this basis, the treatment time is 5-8h.

[0131] Based on the above, the usual operating procedure for reference in step (A) is: using an autoclave, placing the solution a and the substrate in the autoclave. Here, it is not difficult to understand that it is desired that the substrate be completely immersed in the solution a; then the autoclave is sealed and transferred to a vacuum drying oven at a temperature of, for example, 120°C for hydrothermal treatment for 6 hours, and then cooled to room temperature, and the titanium-containing substrate is collected, which is the product A described in this step (A). It is recommended here to rinse with deionized (DI) water several times and dry overnight at a temperature not exceeding 70°C.

[0132] Step (B): calcining the product A at high temperature to obtain product B, namely the electrode (abbreviated as Co x O y / Ti)

[0133] The method of the "high-temperature calcination" is not particularly limited as long as a reaction environment having a certain temperature can be provided, and a conventionally known method can be used.

[0134] For example, the product A may be calcined using a tube furnace or a muffle furnace to obtain cobalt oxide with corresponding morphology on the titanium substrate.

[0135] The high-temperature calcination temperature is preferably 300-500° C. in the treatment temperature; and the treatment time is 2-3 hours.

[0136] 【2】Electrode for electrochemical treatment of liquid to extract bromine (O v -Co x O y / Ti) manufacturing method

[0137] It includes the steps of preparing solution b, and the following step (C);

[0138] Preferably, after step (C), step (D) is further included:

[0139] Steps for preparing solution b

[0140] The solution b contains sodium borohydride (NaBH4) or potassium borohydride (KBH4) or a mixture of the two, and its concentration is preferably 0.025-0.050 mol / L;

[0141] Step (C): using solution b to treat the product B (i.e., the precursor electrode Co) obtained in step (B) x O y / Ti) for processing, The electrode (O v -Co x O y / Ti)

[0142] As for the "treatment" method, it is not difficult to understand that it is desired that product B be completely immersed in solution b; and the immersion time is usually required to be 15-30 minutes.

[0143] Step (D): After the immersion in step (C), the electrode ( v -Co x O y / Ti) for washing and drying

[0144] The method of "washing" is not particularly limited as long as it can selectively remove impurities such as oil stains on the surface. For example, the electrode (O v -Co x O y / Ti) is placed in deionized water or ultrapure water, stirred, and then filtered to perform washing.

[0145] After washing, the product is dried. The drying method is not particularly limited, and any conventional drying method may be employed. For example, the product may be dried in a dryer or a vacuum oven at 60-80° C. for 10-15 hours.

[0146] 【3】Electrode for electrochemical treatment of liquid to extract bromine (O v -Co x O y / Ti)

[0147] The electrode material includes a substrate containing titanium and a cobalt oxide (O v -Co x O y );

[0148] As the electrode material, it can also selectively satisfy any one of the following (I) to (VI) or any combination of several of them; (I) to (VI) are respectively:

[0149] (I) As the substrate, its titanium content is not less than 95%; preferably, a high-purity titanium plate with a titanium content close to 100% is used as the substrate;

[0150] (II) the cobalt oxide having characteristic peaks at the following diffraction angles 2θ (±0.2°): 19.0°, 31.4°, and 36.9° in its powder X-ray diffraction peaks; and / or

[0151] (III) As the cobalt oxide, its powder X-ray diffraction peaks are:

[0152] The characteristic peak at 2θ (±0.2°) = 19.0° corresponds to the (111) crystal plane of cobalt oxide;

[0153] The characteristic peak at 2θ (±0.2°) = 31.4° corresponds to the (220) crystal plane of cobalt oxide;

[0154] The characteristic peak at 2θ (±0.2°) = 36.9° corresponds to the (311) crystal plane of cobalt oxide; and / or,

[0155] The cobalt oxide is preferably cobalt trioxide; and / or,

[0156] (IV) The cobalt oxide with oxygen vacancies preferably includes: linear cobalt oxide with oxygen vacancies (hereinafter referred to as: O v -Co x O y NWs), needle-shaped cobalt oxides with oxygen vacancies (hereinafter referred to as: O v -Co x O y NNs), leaf-shaped cobalt oxides with oxygen vacancies (hereinafter referred to as: O v -Co x O y NLs), plate-like cobalt oxides with oxygen vacancies (hereinafter referred to as: O v -Co x O y Any one or two or more of NPs);

[0157] At this time, as the electrode material, it includes: an electrode having linear cobalt oxide with oxygen vacancies on a substrate (hereinafter referred to as: O v -Co x O y NWs / Ti), an electrode having needle-shaped cobalt oxide with oxygen vacancies on a substrate (hereinafter referred to as: O v -Co x O y NNs / Ti), an electrode having leaf-shaped cobalt oxide with oxygen vacancies on a substrate (hereinafter referred to as: O v -Co x O y NLs / Ti), an electrode having a plate-shaped cobalt oxide with oxygen vacancies on a substrate (hereinafter referred to as: O v -Co x O y Any one or two or more of NPs / Ti); and / or,

[0158] (V) The cobalt oxide preferably includes linear cobalt trioxide (hereinafter referred to as O) with oxygen vacancies. v -Co3O4 NWs), needle-shaped cobalt oxide with oxygen vacancies (hereinafter referred to as: O v -Co3O4 NNs), leaf-shaped cobalt oxide with oxygen vacancies (hereinafter referred to as: O v -Co3O4 NLs), plate-like cobalt oxide with oxygen vacancies (hereinafter referred to as: O v -Co3O4 NPs) any one or two or more;

[0159] At this time, as the electrode material, it includes: a linear cobalt tetroxide electrode with oxygen vacancies on a substrate (hereinafter referred to as: O v -Co3O4 NWs / Ti), an electrode having needle-shaped cobalt tetroxide with oxygen vacancies on the substrate (hereinafter referred to as: O v -Co3O4 NNs / Ti), an electrode having leaf-shaped cobalt tetroxide with oxygen vacancies on a substrate (hereinafter referred to as: O v -Co3O4 NLs / Ti), a plate-shaped cobalt oxide electrode with oxygen vacancies on a substrate (hereinafter referred to as: O v -Co3O4 NPs / Ti) any one or two or more; and / or,

[0160] (VI) As the electrode material, it is preferred to use the above 【2】Used for electrochemical treatment of liquids to extract Bromine electrode (O v -Co x O y / Ti) manufacturing method , prepared.

[0161] 【4】A method for extracting bromine from a liquid, comprising electrochemically treating the liquid to extract the bromine;

[0162] Furthermore, the method includes a step of using gas to perform stripping treatment to collect Br2 formed by the electrochemical treatment.

[0163] The anode during the electrochemical treatment includes: [1] an electrode for electrochemically treating the liquid to extract bromine (Co x O y / Ti), or [3] an electrode for electrochemical treatment of liquids to extract bromine (O v -Co x O y / Ti), or [2] an electrode for electrochemical treatment of liquids to extract bromine (O v -Co x O y / Ti) prepared by the manufacturing method.

[0164] The "bromine-containing liquid" can be any one or more complex bromine-containing wastewaters produced in any chemical production process. For example, high hardness bromine-containing wastewater (containing Ca 2+ Mg 2+ ), high ammonia nitrogen bromine-containing wastewater, high chlorine bromine-containing wastewater, high organic matter bromine-containing wastewater, etc. The initial pH value of the bromine-containing liquid is in the range of 3-7, or can be adjusted to have a pH value in the range of 3-7.

[0165] In fact, during the process of extracting bromine from bromine-containing liquid by electrochemical treatment of the electrode of the present invention, the interference from chloride ions is not too great. However, in order to maximize the oxidation effect of bromine, it is best to ensure that the content of chloride ions in the bromine-containing liquid does not exceed 10,000 mg / L.

[0166] During the electrochemical treatment, the current density is set to 0.5-5 mA / cm 2 , preferably 0.5-3 mA / cm 2 .

[0167] 【5】A device for extracting bromine from a liquid, the device comprising : Electrochemical treatment unit, blowing unit, recovery unit.

[0168] Electrochemical treatment unit

[0169] The electrochemical treatment unit includes a power supply, electrodes and a reactor;

[0170] The reactor comprises a chamber 1 and a chamber 2, wherein the chamber 1 and the chamber 2 are separated by an ion-selective permeable membrane;

[0171] The first chamber is used to contain the liquid containing bromine and to be treated; the second chamber is used to fill the electrolyte;

[0172] The electrodes include an anode and a cathode, and the cathode and the anode are connected to a power source via a wire;

[0173] The anode is placed in chamber one, and the cathode is placed in chamber two;

[0174] There are no special requirements for the specific form of the "reactor", and an example thereof may be a common H-type double-chamber electrolytic cell.

[0175] The "ion-selective permeable membrane" serves to provide a pathway for proton migration and transport, separate gaseous reactants, and block the electrolyte during electrochemical bromine extraction. The gas is not particularly limited, and existing, known membranes can be used; examples include Nafion 211 proton exchange membrane, Nafion 117 proton exchange membrane, and Nafion 115 proton exchange membrane.

[0176] The anode is also called the working electrode, which is an electrode (Co x O y / Ti) prepared by the manufacturing method, or [2] for the electrochemical treatment of liquid to extract bromine electrode (O v -Co x O y / Ti) prepared by the manufacturing method, or [3] an electrode for electrochemical treatment of liquid to extract bromine (O v -Co x O y / Ti).

[0177] The "cathode" is also called a counter electrode, and can be made of materials such as platinum, titanium, and stainless steel.

[0178] In addition, the electrode further comprises a reference electrode, and the reference electrode can be an Ag / AgCl electrode or a saturated calomel electrode.

[0179] Blowing unit

[0180] The blowing unit generally includes a gas generating device and a gas conveying device, wherein the gas conveying device is in communication with chamber one and is used to ventilate the chamber one;

[0181] Furthermore, the gas delivery device is also connected to chamber two for ventilating chamber two when necessary; preferably, ventilation is performed from the bottom of chamber one or two to blow out the gas in the liquid to the maximum extent.

[0182] As the "gas-generating device", its main function is to ventilate or ventilate a specific device, and its common existing device can be an air pump;

[0183] The "gas delivery device" as described above mainly functions to deliver and stop gas or airflow, and a common existing device thereof includes a delivery pipeline with a control valve.

[0184] Recovery Unit

[0185] The recovery unit includes a delivery pipeline and a gas absorbent; the recovery unit is connected to the first chamber through the delivery pipeline and is used to receive the gas discharged from the first chamber.

[0186] The main function of the "gas absorbent" is to absorb the blown bromine, so a typical absorbent is, for example, KI solution.

[0187] Typically, the present invention provides a specific form of bromine extraction device in liquid such as Figure 1 As shown, it includes a reactor 100, an electrochemical unit 200, a blowing unit 300, and a recovery unit 400;

[0188] The reactor 100 is divided into a chamber 1 (also referred to as an anode chamber) 110 and a chamber 2 (also referred to as a cathode chamber) 120 by a Nafion 117 proton exchange membrane 240; the chamber 110 is used to contain a bromine-containing liquid, and the chamber 2 120 is used to contain an electrolyte;

[0189] The electrochemical cell 200 includes a power source 210 and electrodes, wherein the electrodes include an anode 220 and a reference electrode 250 disposed in chamber 1 10 , and a cathode 230 disposed in chamber 2 120 ;

[0190] The blowing unit 300 includes an air pump 310 and a delivery pipe 320 for passing the gas generated by the air pump 310 into the chamber 1 110 and the chamber 2 120;

[0191] The recovery unit 400 includes an absorbent 410 and a delivery pipe 420 for delivering the gas overflowing from the chamber 110 into a container containing the absorbent 410 .

[0192] The operating principle of bromine extraction using the device provided in the present invention [5] is as follows:

[0193] introducing bromine-containing liquid into the chamber 110;

[0194] introducing electrolyte into the second chamber 120;

[0195] When the power supply 210 is turned on, the bromide ions in the bromine-containing liquid in the chamber 110 are oxidized into bromine under the action of the anode 220;

[0196] The gas from the air pump 310 enters the chamber 110 from the bottom through the delivery pipe 320, blows the bromine produced by oxidation out of the chamber 110, and is transported out of the chamber 110 through the delivery pipe 420, and then absorbed by the absorbent 410, completing the collection of bromine.

[0197] 【6】 The steps of extracting bromine using the extraction device include:

[0198] Step S1:

[0199] introducing bromine-containing liquid into the first chamber;

[0200] introducing electrolyte into the second chamber;

[0201] The initial pH value of the bromine-containing liquid is in the range of 3-7, preferably 3-5;

[0202] The chloride ion content in the bromine-containing liquid does not exceed 10,000 mg / L

[0203] The initial pH value of the electrolyte is in the range of 3-7, preferably 3-5;

[0204] In S2, during the electrochemical treatment, the current density is set to 0.5-5 mA / cm 2 , preferably 0.5-3 mA / cm 2 .

[0205] Ventilation is performed to blow out the bromine obtained through electrochemical treatment in the chamber.

[0206] The present invention is further described below in conjunction with specific embodiment, but embodiment does not limit the present invention in any form.Unless otherwise specified, the reagent, method and equipment adopted in the present invention are conventional reagents, methods and equipment in the art.The essential characteristics of the present invention and remarkable effect can be reflected from the following examples, and described embodiment is a part of embodiment of the present invention, rather than whole embodiment, therefore, they do not limit the present invention in any way, and those skilled in the art make some non-essential improvements and adjustments based on the content of the present invention, all belong to protection scope of the present invention.

[0207] Example 1

[0208] 1. Preparation of Co3O4 NNs / Ti electrode

[0209] (1) Pretreatment of titanium substrate

[0210] The titanium plate was polished with 500-mesh (25 μm) sandpaper until the surface was free of scratches, washed three times with ethanol and deionized water in sequence, and then dried for use.

[0211] (2) Prepare precursor solution a

[0212] A precursor solution was prepared by dissolving 25 mmol Co(NO3)2·6H2O, 50 mmol NH4F and 125 mmol Co(NH2)2 in 65 mL distilled water and stirring the mixture at 750 rpm using a magnetic stirrer for 30 min.

[0213] (3) Preparation of electrodes

[0214] (A) The precursor solution was transferred to a 100 mL Teflon-lined stainless steel autoclave. A pretreated high-purity titanium plate was then immersed in the precursor solution. The autoclave was sealed and transferred to a vacuum drying oven at 120°C for 6 hours before cooling to room temperature. The high-purity titanium plate electrode was collected, rinsed several times with deionized (DI) water, and dried at 60°C overnight.

[0215] (B) Annealing treatment at 400 °C in air for 2 h to obtain Co3O4 NNs on titanium substrate.

[0216] 2. O v Preparation of Co3O4 NNs / Ti electrode

[0217] (C) The Co3O4 NNs / Ti electrode prepared in (B) was immersed in 0.025 M NaBH4 solution for 15 min, then washed with ultrapure water and dried in a vacuum oven at 60°C for 12 h to obtain Ov-Co3O4 NNs / Ti.

[0218] The prepared Co3O4 NNs / Ti electrode, O v -X-ray diffraction pattern of Co3O4 NNs / Ti electrode Figure 8 As shown, Co3O4NNs, O v -Co3O4 NNs have the same powder X-ray diffraction peaks, with characteristic peaks at diffraction angles 2θ (±0.2°): 19.0°, 31.4°, and 36.9°; wherein, the characteristic peak at 2θ (±0.2°) = 19.0° corresponds to the (111) crystal plane of cobalt oxide; the characteristic peak at 2θ (±0.2°) = 31.4° corresponds to the (220) crystal plane of cobalt oxide; the characteristic peak at 2θ (±0.2°) = 36.9° corresponds to the (311) crystal plane of cobalt oxide.

[0219] Figure 9 O v -10μm SEM image of Co3O4 NNs / Ti electrode material, Figure 10 O v -500nm scanning electron microscopy image of Co3O4 NNs / Ti electrode material; showing O v -In the Co3O4 NNs / Ti electrode material, O v -Co3O4 is also needle-shaped.

[0220] Figure 11 For Co3O4 NNs / Ti, O v -X-ray photoelectron full spectrum scanning of Co3O4 NNs / Ti electrode material;

[0221] Figure 12 Co3O4 NNs / Ti, O v -Electron paramagnetic resonance (EPR) spectrum of Co3O4 NNs / Ti electrode material. It can be clearly seen from the figure that only O v -A sharp and strong signal was detected for the Co3O4 NNs / Ti electrode material at g = 2.003, indicating thatv -Co3O4 NNs / Ti electrode materials contain abundant oxygen vacancies O v .

[0222] 3. Preparation of Co3O4 NWs / Ti electrode

[0223] Basically the same as [1. Preparation of Co3O4 NNs / Ti electrode], the only difference is:

[0224] The prepared precursor solution a has different concentrations of Co(NO3)2·6H2O, NH4F, and Co(NH2)2, specifically: 5mmol Co(NO3)2·6H2O, 10mmol NH4F, and 25mmol Co(NH2)2;

[0225] The rest is the same as [1. Preparation of Co3O4 NNs / Ti electrode].

[0226] 4. O v Preparation of Co3O4 NWs / Ti electrode

[0227] (C) The Co3O4 NWs / Ti electrode prepared in (B) was immersed in 0.025 M NaBH4 solution for 15 min, then washed with ultrapure water and dried in a vacuum oven at 60°C for 12 h to obtain Ov-Co3O4 NWs / Ti.

[0228] 5. Preparation of Co3O4 NLs / Ti electrode

[0229] Basically the same as [1. Preparation of Co3O4 NNs / Ti electrode], the only difference is:

[0230] The prepared precursor solution a has different concentrations of Co(NO3)2·6H2O, NH4F, and Co(NH2)2, specifically: 50mmol Co(NO3)2·6H2O, 100mmol NH4F, and 250mmol Co(NH2)2;

[0231] The rest is the same as [1. Preparation of Co3O4 NNs / Ti electrode].

[0232] 6. O v Preparation of Co3O4 NLs / Ti electrode

[0233] (C) The Co3O4 NLs / Ti electrode prepared in (B) was immersed in 0.025 M NaBH4 solution for 15 min, then washed with ultrapure water and dried in a vacuum oven at 60°C for 12 h to obtain Ov-Co3O4 NLs / Ti.

[0234] 7. Preparation of Co3O4 NPs / Ti electrode

[0235] Basically the same as [1. Preparation of Co3O4 NNs / Ti electrode], the only difference is:

[0236] The prepared precursor solution a has different concentrations of Co(NO3)2·6H2O, NH4F, and Co(NH2)2, specifically: 50mmol Co(NO3)2·6H2O, 0mmol NH4F, and 250mmol Co(NH2)2;

[0237] The rest is the same as [1. Preparation of Co3O4 NNs / Ti electrode].

[0238] 8. O v -Preparation of Co3O4 NPs / Ti electrode

[0239] (C) The Co3O4 NPs / Ti electrode prepared in (B) was immersed in 0.025 M NaBH4 solution for 15 min, then washed with ultrapure water and dried in a vacuum oven at 60 °C for 12 h to obtain Ov-Co3O4 NPs / Ti.

[0240] 9. In addition, this embodiment also provides several common electrodes:

[0241] Titanium-based tin dioxide (its preparation method can refer to Patent Document 3: Publication No. CN101857288A) Example 1;

[0242] Graphite (purchased from Changsong New Materials);

[0243] Titanium-based ruthenium dioxide (its preparation method can refer to Patent Document 4: Publication No. CN110129821A) Example 1;

[0244] Titanium-based lead dioxide (its preparation method can refer to Patent Document 5: Publication No. CN111675289A) Example 1;.

[0245] Example 2

[0246] The reaction device is as shown in the attached Figure 1 , respectively using the Co3O4 NNs / Ti electrode prepared in Example 1, O v -Co3O4 NNs / Ti electrode, as well as titanium-based tin dioxide, graphite, titanium-based ruthenium dioxide, and titanium-based lead dioxide as anodes (φ20 mm × 30 mm) formed different experimental groups;

[0247] The cathode is made of stainless steel sheet, and its area is the same as that of the anode.

[0248] like Figure 1The reaction device shown has a chamber 2 120 (ie, cathode chamber) with a capacity of 100 mL and a chamber 110 (ie, anode chamber) with a capacity of 100 mL, separated by a Nafion 117 proton exchange membrane.

[0249] Preparation of Br - The simulated wastewater with a concentration of 1500 mg / L was used as the experimental anolyte in chamber 110 (the amount used in each group in subsequent experiments was 75 mL);

[0250] Sodium sulfate solution is passed through chamber 2 120 as the electrolyte;

[0251] Electrochemical treatment conditions: pH = 5, current density 0.5 mA cm -2 、c(Cl - )=0, conductivity is 4000 μS / cm, and aeration rate is 2 L / min. Electrolysis is carried out for 600 min, and sampling is carried out every 60 min.

[0252] The Br of the above-mentioned anodes can be obtained - Degradation rate, such as Figure 2 As shown in the figure, it can be seen that the bromide ion degradation rate of titanium-based tin dioxide, graphite, titanium-based ruthenium dioxide, and titanium-based lead dioxide as anodes is less than 60%, and titanium-based tin dioxide is even less than 50%. The cobalt oxide nanoneedle electrode has better degradation effect than other types of electrodes, and the oxygen vacancy structure performs better, with a bromide ion degradation rate greater than 80%.

[0253] Example 3

[0254] The reaction apparatus is structurally the same as in Example 2;

[0255] In this embodiment, v -Co3O4 NNs / Ti as anode (φ20mm×30mm);

[0256] The cathode is made of stainless steel sheet, and its area is the same as that of the anode.

[0257] Br was prepared with chloride ion concentrations of 0, 500, 1000, 1500, 3000, 5000, and 10000 mg / L. - Seven groups of simulated wastewater with a concentration of 1500 mg / L were used as the experimental anolyte in chamber 110 (the amount of each group used in subsequent experiments was 75 mL);

[0258] Sodium sulfate solution is passed through chamber 2 120 as the electrolyte;

[0259] Electrochemical treatment conditions: pH = 5, current density 0.5 mA cm -2, conductivity of 4000μS / cm, and aeration volume of 2L / min were used for electrolysis for 600min, and samples were taken every 60min for measurement.

[0260] The degradation rate of bromide ions under different chloride ion concentrations is obtained, as shown in the attached figure. Figure 3 As shown in the figure, it can be seen that in the absence of chloride ions or at low chloride ion concentrations (no more than 10,000 mg / L), there is almost no effect on bromide ion degradation. However, when the chloride ion concentration is too high (10,000 mg / L), bromide ion degradation is inhibited to a certain extent. Analysis suggests that the reason may be that the high chloride ion concentration competes with bromide ions for adsorption at the active sites, thus affecting the bromide ion degradation effect.

[0261] Example 4

[0262] The reaction apparatus is structurally the same as in Example 2;

[0263] In this embodiment, Co3O4 NNs / Ti, O v -Co3O4 NNs / Ti, Co3O4 NWs / Ti, O v -Co3O4 NWs / Ti, Co3O4 NLs / Ti, O v -Co3O4 NLs / Ti, Co3O4 NPs / Ti, O v -Co3O4 NPs / Ti as anode (φ20mm×30mm);

[0264] The cathode is made of stainless steel sheet, and its area is the same as that of the anode.

[0265] Preparation of Br - The simulated wastewater with a concentration of 1500 mg / L was used as the experimental anolyte in chamber 110 (the amount used in each group in subsequent experiments was 75 mL);

[0266] Sodium sulfate solution is passed through chamber 2 120 as the electrolyte;

[0267] Electrochemical treatment conditions: pH = 5, current density 0.5 mA cm -2 、c(Cl - )=0, conductivity is 4000μS / cm, and aeration rate is 2L / min. Electrolysis is carried out for 600min, and sampling is carried out every 60min.

[0268] The bromide ion degradation rate and bromine elemental generation rate of each electrode material are shown in the attached figure. Figure 4As shown in the figure, it can be seen that the four forms of cobalt oxide nanoelectrodes all have high bromide ion degradation rates and bromine elemental recovery rates, among which the oxygen vacancy structure has better effects than the original structure, and the degradation effect of the nanoplate electrode is better than the other three structures. The bromide ion degradation rate of the oxygen vacancy cobalt oxide nanoplate electrode under the reaction conditions exceeds 90%, and the bromine elemental generation rate exceeds 80%.

[0269] Example 5

[0270] The actual wastewater used was the biochemical secondary effluent from a chemical plant in Inner Mongolia. The main water quality indicators of the actual wastewater are shown in Table 1 below.

[0271] Table 1 List of water quality parameters of brominated wastewater from a chemical plant in Inner Mongolia (unit: mg / L)

[0272] project pH Chroma Turbidity <![CDATA[Br - ]]> <![CDATA[Cl - ]]> COD TOC content 5-6 40-60 20-25 5805.22 804.91 5870 2839

[0273] The reaction apparatus is structurally the same as in Example 2;

[0274] In this embodiment, SnO2 / Ti, graphite, RuO2 / Ti, PbO2 / Ti, Co3O4 NNs / Ti and O v -Co3O4NNs / Ti as anode (φ20 mm × 30 mm) to form different experimental groups;

[0275] The cathode is made of stainless steel sheet, and its area is the same as that of the anode.

[0276] Sodium sulfate solution is passed through chamber 2 120 as the electrolyte;

[0277] Electrochemical treatment conditions: pH = 5, current density 0.5 mA cm -2 , conductivity of 4000μS / cm, and aeration volume of 2L / min were used for electrolysis for 600min, and samples were taken every 60min for measurement.

[0278] The actual wastewater bromide ion degradation rate, bromine elemental generation rate, chloride ion degradation rate, TOC and COD removal rate are shown in the attached Figure 5 As shown, from Figure 5 It can be seen that all six anodes have high TOC and COD removal rates. Except for the tin dioxide anode, the chloride ion degradation rates of other electrodes are over 80%. v -The bromide ion degradation rate and bromine elemental generation rate of Co3O4 NNs / Ti anode are the highest, exceeding 70% and 60% respectively, which are similar to the effects of simulated wastewater; the bromide ion degradation rate and bromine elemental generation rate of Co3O4 NNs / Ti anode are second best.

[0279] The research focused on calculating O v-The current efficiency and specific energy consumption of Co3O4 NNs / Ti electrode are shown in the attached Figure 6 As shown in the figure, the current efficiency of this electrode decreases slightly over time within 600 minutes, but ultimately remains above 70%. The specific energy consumption is initially 1.59 kJ / g and rises slightly to 1.76 kJ / g over time, resulting in an extremely low overall specific energy consumption.

[0280] Example 6

[0281] According to the method of Example 2;

[0282] Reuse freshly prepared O v -Co3O4 NNs / Ti was used as the anode, which was repeatedly rinsed with deionized water after each use and then placed in a drying oven for drying.

[0283] The electrocatalytic experiment was carried out under the same conditions as in Example 2, with 10 consecutive cycles.

[0284] The experimental results are as follows Figure 7 As shown in the figure, the bromide ion degradation rate is maintained above 80%. It can be concluded that the titanium-based oxygen vacancy cobalt tetroxide nanomaterial electrode has good stability after 10 cycles and has good reusability.

[0285] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for extracting bromine from a liquid, characterized in that: The bromine-containing liquid is electrochemically treated to generate Br - The conversion process to Br2; Wherein, during the electrochemical treatment: The current density was set to 0.5-5 mA / cm 2 ; Electrode materials used as anodes include: a substrate comprising titanium, and cobalt oxide disposed on the substrate; The cobalt oxide has characteristic peaks in its powder X-ray diffraction peaks at the following diffraction angles 2θ (±0.2°): 19.0°, 31.4°, and 36.9°; Wherein, electron paramagnetic resonance detection shows that the cobalt oxide has oxygen vacancies.

2. The method for extracting bromine from liquid according to claim 1, characterized in that: The preparation of the electrode material comprises: preparing a precursor electrode, the precursor electrode comprising a substrate containing titanium, and cobalt oxide on the substrate; The precursor electrode is treated with sodium borohydride and / or potassium borohydride to obtain the electrode.

3. The method for extracting bromine from a liquid according to claim 2, wherein the sodium borohydride and / or potassium borohydride is prepared into a solution with a concentration of 0.025-0.050 mol / L; The processing time is 15-30 minutes.

4. The method for extracting bromine from a liquid according to any one of claims 1 to 3, characterized in that: The bromine-containing liquid has a pH value in the range of 3-7; Alternatively, the bromine-containing liquid has a pH value in the range of 3-5.

5. The method for extracting bromine from liquid according to claim 4, characterized in that: The pH value of the bromine-containing liquid after adjustment is in the range of 3-7; Alternatively, the pH value of the bromine-containing liquid after adjustment is in the range of 3-5.

6. The method for extracting bromine from a liquid according to any one of claims 1 to 3, characterized in that: The pH value of the bromine-containing liquid after adjustment is in the range of 3-7; Alternatively, the pH value of the bromine-containing liquid after adjustment is in the range of 3-5.

7. The method for extracting bromine from a liquid according to any one of claims 1 to 3 or 5, characterized in that: It also includes a stripping process using a gas to collect Br2 formed by the electrochemical process.

8. The method for extracting bromine from liquid according to claim 4, characterized in that: It also includes a stripping process using a gas to collect Br2 formed by the electrochemical process.

9. The method for extracting bromine from liquid according to claim 6, characterized in that: It also includes a stripping process using a gas to collect Br2 formed by the electrochemical process.

10. A device for extracting bromine from liquid, characterized in that: including an electrochemical treatment unit; The electrochemical treatment unit includes electrodes and a reactor; The reactor comprises a chamber 1 and a chamber 2, wherein the chamber 1 and the chamber 2 are separated by an ion-selective permeable membrane; The chamber 1 is used to accommodate the liquid containing bromine and to be treated; The second chamber is used to fill the electrolyte; The electrodes include an anode and a cathode; the anode is placed in chamber one, and the cathode is placed in chamber two; Electrode materials used as anodes include: a substrate comprising titanium, and cobalt oxide disposed on the substrate; The cobalt oxide has characteristic peaks in its powder X-ray diffraction peaks at the following diffraction angles 2θ (±0.2°): 19.0°, 31.4°, and 36.9°; Wherein, electron paramagnetic resonance detection shows that the cobalt oxide has oxygen vacancies.

11. The device for extracting bromine from liquid according to claim 10, characterized in that: The preparation of the electrode material comprises: preparing a precursor electrode, the precursor electrode comprising a substrate containing titanium, and cobalt oxide on the substrate; The precursor electrode is treated with sodium borohydride and / or potassium borohydride to obtain the electrode.

12. The device for extracting bromine from liquid according to claim 10 or 11, characterized in that: Also includes a blow-out unit; The blowing unit is in communication with chamber one and is used to ventilate chamber one; and / or, Also includes a recycling unit; The recovery unit is communicated with the first chamber and is used for receiving the gas exhausted from the first chamber.

13. A method for extracting bromine from liquid using the apparatus according to any one of claims 10 to 12, characterized in that: The following steps are involved: Step S1: introducing bromine-containing liquid into the first chamber; introducing electrolyte into the second chamber; Step S2, applying electricity to electrochemically treat the bromine-containing liquid in the first chamber; Step S3, Ventilation is performed to blow out the bromine obtained through electrochemical treatment in the chamber.

14. The method for extracting bromine from liquid according to claim 13, characterized in that: In S1, the bromine-containing liquid has a pH value in the range of 3-7; Alternatively, in S1, the pH value of the bromine-containing liquid is in the range of 3-5.

15. The method for extracting bromine from liquid according to claim 14, characterized in that: In S1, the initial pH value of the desired electrolyte is maintained in the range of 3-7; Alternatively, in S1, the initial pH value of the desired electrolyte is maintained in the range of 3-5.

16. The method for extracting bromine from a liquid according to any one of claims 13 to 15, characterized in that: In S2, during the electrochemical treatment, the current density is set to 0.5-5 mA / cm 2 ; Alternatively, in S2, during the electrochemical treatment, the current density is set to 0.5-3 mA / cm 2 .

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