Electrode material and preparation method thereof, method for treating organic wastewater and producing hydrogen through coupling, and organic wastewater treatment device

Abstract

The invention provides an electrode material and a preparation method thereof, a method for treating organic wastewater and producing hydrogen through coupling and an organic wastewater treatment device, and belongs to the technical field of electro-catalysis. The preparation method of the electrode material comprises the following steps: performing intermediate layer deposition on a pretreated porous carrier through atomic layer deposition to obtain a porous carrier with an intermediate layer deposited on the surface; performing catalytic layer deposition on the porous carrier with the middle layer deposited on the surface through atomic layer deposition to obtain a porous carrier with the catalytic layer and the middle layer deposited in sequence from outside to inside; carrying out thermal annealing treatment on the porous carrier on which the catalyst layer and the middle layer are sequentially deposited from outside to inside to obtain an electrode material; the forbidden bandwidth of the material of the middle layer is larger than 5 eV, and the heat conductivity of the material of the middle layer is larger than 250 W / (m.K). The middle layer is formed between the porous carrier and the catalytic layer, so that the electron injection efficiency and path of electrons from the porous carrier to the catalytic layer can be adjusted and optimized, and the catalytic degradation efficiency of the catalytic layer on organic wastewater is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrocatalysis, in particular to an electrode material and a preparation method thereof, a method for treating organic wastewater coupled with hydrogen production, and an organic wastewater treatment device; more particularly to an electrode material and a preparation method thereof, a method for treating integrated circuit organic wastewater coupled with hydrogen production, and an organic wastewater treatment device. BACKGROUND

[0002] The production process of integrated circuits requires the use of various chemical reagents, and a large amount of industrial wastewater is generated during the production process. The pollutant composition is relatively complex and has strong toxicity, and needs to be discharged after the pollutants are removed. According to the type, the integrated circuit wastewater is usually divided into acid-base wastewater, organic wastewater, fluorine-containing wastewater and ammonia-nitrogen wastewater, etc., among which the organic impurities in the organic wastewater are difficult to remove.

[0003] The integrated circuit organic wastewater (hereinafter referred to as organic wastewater) mainly comes from the process sections such as silicon wafer cleaning, chemical mechanical polishing and photoetching in the production process, and its main components include solvents (organic impurities) such as isopropyl alcohol, propylene glycol monomethyl ether acetate, acetone, xylene, etc. The above solvents have the characteristics of high chemical oxygen demand (COD) and low biodegradability.

[0004] In the related art, a membrane bioreactor is usually used to preliminarily reduce the COD content in the organic wastewater, and then a Fenton reaction is performed. However, since the pH value of the Fenton reaction is in the range of 2-4, and the pH of the organic wastewater is higher than the above range, an acid solution needs to be added for pH adjustment, and divalent iron ion inorganic salt is usually used in the catalyst. After the purification of the organic wastewater is completed, the divalent iron ion is difficult to recycle and utilize, which brings secondary pollution to the environment. SUMMARY

[0005] Therefore, in order to at least partially solve the above-mentioned technical problems, the present application provides an electrode material and a preparation method thereof, a method for treating organic wastewater coupled with hydrogen production, and an organic wastewater treatment device.

[0006] According to an embodiment of the first aspect of the present application, a preparation method of an electrode material is provided, comprising: depositing an intermediate layer on a pretreated porous carrier by atomic layer deposition to obtain a porous carrier with the intermediate layer deposited on the surface; depositing a catalytic layer on the porous carrier with the intermediate layer deposited on the surface by atomic layer deposition to obtain a porous carrier with the catalytic layer and the intermediate layer deposited from outside to inside; and performing heat annealing treatment on the porous carrier with the catalytic layer and the intermediate layer deposited from outside to inside to obtain the electrode material; wherein the material of the intermediate layer has a band gap > 5eV, and the material of the intermediate layer has a thermal conductivity > 250W / (m·K).

[0007] According to the embodiment of the second aspect of the present application, there is provided an electrode material having a catalytic layer, an intermediate layer and a porous carrier arranged from outside to inside, which is prepared by the preparation method as described above.

[0008] According to the embodiment of the third aspect of the present application, there is provided a method for treating organic wastewater coupled with hydrogen production using the electrode material as described above, comprising: step a: adding hydrogen peroxide solution into the organic wastewater to obtain organic wastewater added with hydrogen peroxide solution; step b: under the irradiation of an ultraviolet lamp, using carbon material as cathode and the electrode material as anode, applying forward bias to preliminarily degrade organic impurities in the organic wastewater by photoelectro-Fenton reaction; step c: turning off the ultraviolet lamp, using carbon material as anode and the electrode material as cathode, applying reverse bias to produce hydrogen by electrolysis while removing degradation intermediates occupying active sites on the electrode surface; step d: taking one step b and one step c as one operation cycle, repeating n groups of operation cycles to achieve deep removal of organic impurities in the organic wastewater; n is an integer greater than 1.

[0009] According to the embodiment of the fourth aspect of the present application, there is provided an organic wastewater treatment device, comprising an organic wastewater treatment tank and a shell; wherein the organic wastewater treatment tank comprises a first partition plate and a second partition plate arranged in sequence from inside to outside, the first partition plate and the second partition plate divide the organic wastewater treatment tank into a first wastewater tank, a second wastewater tank and a third wastewater tank, the first wastewater tank is located in the first partition plate, the second wastewater tank is located between the first partition plate and the second partition plate, and the third wastewater tank is located between the second partition plate and the shell; the first partition plate has a first through hole, and the outer side of the first partition plate is coated with the electrode material as described above; the second partition plate has a second through hole, and the pore size of the second through hole on the third wastewater tank side is smaller than that of the second through hole on the second wastewater tank side; the top of the first wastewater tank is provided with an organic wastewater inlet, and the top of the second wastewater tank is provided with a hydrogen outlet and an ultraviolet lamp placing port; the upper part of the third wastewater tank is provided with an oxygen outlet, and the bottom of the third wastewater tank is provided with a wastewater outlet; a carbon material electrode is arranged between the third wastewater tank and the shell; wherein under the irradiation of the ultraviolet lamp, the organic wastewater mixed with hydrogen peroxide solution in the first wastewater tank flows into the second wastewater tank through the first through hole to carry out photoelectro-Fenton reaction for preliminary degradation of organic impurities; part of the organic wastewater after preliminary degradation flows into the third wastewater tank through the second through hole, and the organic wastewater in the second wastewater tank and the third wastewater tank carries out electrolysis reaction to produce hydrogen, the obtained hydrogen is discharged through the hydrogen outlet of the second wastewater tank, the obtained oxygen is discharged through the oxygen outlet of the third wastewater tank, and the purified organic wastewater is discharged through the wastewater outlet of the third wastewater tank.

[0010] The preparation method of the electrode material according to the embodiment of the present application sequentially deposits the intermediate layer and the catalytic layer on the porous carrier by using the atomic layer deposition, coordinates the difference between the porous carrier and the catalytic layer by using the intermediate layer, so that the electrons can flow from the porous carrier to the catalytic layer through the intermediate layer by the quantum tunneling effect, optimizes the electron coupling at different interfaces, and improves the intrinsic catalytic activity of the catalytic layer. When the electrode material prepared by the above method is used for subsequent treatment of organic wastewater, the mass transfer and charge separation of reactants and products at the interface are promoted, and the catalytic efficiency is improved, thereby improving the catalytic degradation effect on the organic wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0011] The above and other objects, features and advantages of the present application will become more apparent from the following description of embodiments of the present application with reference to the accompanying drawings.

[0012] Figure 1 A flow chart of the preparation method of the electrode material according to the embodiment of the present application is shown;

[0013] Figure 2 A cross-sectional schematic view of the organic wastewater treatment device according to the embodiment of the present application is shown;

[0014] Figure 3 A curve graph of the COD content of the organic wastewater of Example 1, Comparative Example 1 and Comparative Example 2 according to the embodiment of the present application with respect to time is shown;

[0015] Figure 4 A curve graph of the COD content of the organic wastewater of Example 2, Comparative Example 3 and Comparative Example 4 according to the embodiment of the present application with respect to time is shown;

[0016] Figure 5 A curve graph of the Tafel slope of Example 1, Example 2, Comparative Example 1 and Comparative Example 3 according to the embodiment of the present application with respect to time is shown.

[0017] In the above drawings, the meanings of the reference signs are as follows:

[0018] 1, organic wastewater treatment tank;

[0019] 11, first partition; 12, second partition; 13, first wastewater tank; 14, second wastewater tank; 15, third wastewater tank; 16, electrode material; 17, carbon material electrode;

[0020] 111, first through hole; 121, second through hole; 131, organic wastewater inlet; 141, hydrogen gas outlet; 142, ultraviolet lamp placement opening; 151, oxygen gas outlet; 152, wastewater outlet;

[0021] 2, shell;

[0022] 3, support frame;

[0023] 31. Waste water pipe outlet. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. It is to be understood, however, that these descriptions are merely exemplary and are intended to illustrate the scope of the present application, not to limit it.

[0025] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present application. However, it will be apparent to one skilled in the art that one or more embodiments can be practiced without these specific details. In other instances, well-known structures and techniques have not been described in detail in order to avoid obscuring aspects of the present application.

[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the term "includes" indicates the presence of the features, steps, operations, but does not exclude the presence or addition of one or more other features.

[0027] At present, advanced oxidation processes are commonly used to treat organic wastewater with high toxicity and difficult to degrade, such as the commonly used Fenton reaction. However, the Fenton reaction has the following disadvantages: it is difficult to directly treat organic wastewater with high COD content (such as 1000-50000 mg / L), and is usually used in combination with a membrane bioreactor. The membrane bioreactor is used to preliminarily decompose the COD content, which increases the cost and complicates the process. At the same time, in the Fenton reaction process, inorganic salts containing divalent iron ions need to be added, and the recycling of divalent iron ions is difficult, which may introduce new impurities into the organic wastewater.

[0028] In the process of implementing the concept of the present application, it is found that by introducing an intermediate layer into the electrode material, the electronic coupling between different interfaces is optimized by using the intermediate layer, the injection efficiency and path of electrons between the porous carrier and the catalytic layer are optimized, and the catalytic efficiency of the electrode formed by the electrode material in the degradation of organic impurities in organic wastewater is improved.

[0029] Specifically, according to an embodiment of one aspect of the present application, a preparation method of an electrode material is provided, Figure 1 A flowchart of the preparation method of the electrode material of the embodiment of the present application is shown. As shown in the figure, Figure 1 The preparation method includes steps S101-S103.

[0030] In step S101, the pretreated porous carrier is deposited with an intermediate layer by atomic layer deposition, to obtain a porous carrier with the intermediate layer deposited on the surface.

[0031] At step S102, a porous carrier with an intermediate layer deposited thereon is subjected to catalytic layer deposition by atomic layer deposition, to obtain a porous carrier with a catalytic layer and an intermediate layer deposited thereon from outside to inside.

[0032] At step S103, the porous carrier with a catalytic layer and an intermediate layer deposited thereon from outside to inside is subjected to heat annealing treatment, to obtain an electrode material.

[0033] According to an embodiment of the present application, the material of the intermediate layer has a band gap > 5 eV, and the material of the intermediate layer has a thermal conductivity > 250 W / (m·K). The intermediate layer has a large band gap, and such an intermediate layer can use an insulating material or a wide-bandgap semiconductor. The porous carrier has good electrical conductivity, and the catalytic layer can be a semiconductor material. Direct contact between the porous carrier and the catalytic layer will cause charge rearrangement due to the difference in work function, resulting in a Schottky barrier that hinders electron migration to some extent. Inserting the intermediate layer with the above-mentioned band gap between the conductive porous carrier and the catalytic layer optimizes the injection efficiency and path of electrons from the porous carrier to the catalytic layer, and improves the intrinsic catalytic activity of the catalytic layer. The material of the intermediate layer has high thermal conductivity, so that the intermediate layer rapidly and uniformly spreads the heat generated by the catalytic layer during the electrocatalysis process to the porous carrier, avoiding local overheating, improving the thermal stability and service life of the catalytic layer, and further improving the reliability of the electrode formed by the aforementioned electrode material.

[0034] In the present application, "atomic layer deposition" can be understood as a process of thin film growth layer by layer on the atomic or molecular level. Further, the atomic layer deposition of the present application is a chemical deposition process.

[0035] In some embodiments, the porous carrier includes a nickel foam. The nickel foam has a three-dimensional hollow structure, is suitable for providing a core skeleton for the electrode material, and provides a large attachment area for the intermediate layer and the catalytic layer of the atomic layer deposition, increases the loading of active sites, and provides mechanical support and structural stability for the electrode material.

[0036] In some embodiments, the material of the intermediate layer includes any one of aluminum nitride or beryllium oxide. It can be understood that both aluminum nitride and beryllium oxide are insulating materials. Based on the insulating material being located between the porous carrier and the catalytic layer, the intermediate layer promotes the flow of electrons from the porous carrier to the active sites of the catalytic layer by quantum tunneling effect, and further adjusts and optimizes the injection efficiency and path from the porous carrier to the active sites of the catalytic layer, so that the Fermi level of the catalytic layer is at a position more conducive to the adsorption and desorption of hydrogen in the electrolytic hydrogen production, and further improves the intrinsic catalytic activity of the catalytic layer.

[0037] In some embodiments, the material of the catalytic layer includes a two-dimensional transition metal chalcogenide, which can be molybdenum sulfide (MoS2), for example.

[0038] It can be understood that molybdenum sulfide has a layered structure, a sandwich-like structure formed by alternating arrangement of molybdenum atoms and sulfur atoms, and the sandwich is sandwiched between two layers of sulfur atom layers by molybdenum atom layers. The edge sites (such as S atoms) and defect sites constitute the main active sites. In the subsequent formation of electrode materials, these active sites promote the desorption and adsorption of hydrogen in the electrocatalysis process; in the electro-Fenton process, molybdenum sulfide can promote the generation of sulfate radicals and hydroxyl radicals by regulating the process of electron transfer, and form singlet oxygen, or by means of electron transfer between organic impurities, etc., to synergistically promote the degradation of organic impurities.

[0039] Hereinafter, taking aluminum nitride (AlN) as an example, the deposition process of forming the aluminum nitride intermediate layer is described:

[0040] When the temperature of the substrate reaches 300-400°C (for example, it can be 300°C, 350°C or 400°C), AlN film deposition is performed on the pretreated porous carrier, and trimethylaluminum can be selected as the Al source, with a flow time of 1s and nitrogen blowing for 5s; ammonia (NH3) is used as the N source, with a flow time of 2s and nitrogen (N2) blowing for 10s; the Al source and the N source are alternately grown for 8-12 times (for example, 8 times, 10 times or 12 times), and the deposition of the aluminum nitride intermediate layer is completed.

[0041] Hereinafter, taking molybdenum sulfide (MoS2) as an example, the deposition process of forming the molybdenum sulfide catalytic layer is described:

[0042] On the basis of the above-mentioned aluminum nitride intermediate layer, molybdenum pentachloride (MoCl5) is selected as the Mo source, with a flow time of 3s and nitrogen blowing for 15s; hydrogen sulfide (H2S) is selected as the S source, with nitrogen blowing for 20s; the Mo source and the S source are alternately grown for 48-52 times (for example, 48 times, 50 times or 52 times), and the deposition of the MoS2 catalytic layer is completed.

[0043] In some embodiments, the temperature of the thermal annealing process is 300-500°C, and the thermal annealing process is performed in a hydrogen atmosphere. The above temperature range helps to provide atomic rearrangement energy, promote the formation of a relatively complete and ordered crystal structure in the catalytic layer of the electrode material, improve the electronic conductivity, and activate and optimize the electrocatalytic performance. At the same time, the above temperature range helps to promote the interfacial bonding force between the porous carrier, the intermediate layer, and the catalytic layer, realize the atomic interdiffusion and chemical bonding of the above layers at the interface, reduce the risk of peeling or delamination between the above layers during subsequent cyclic use, and improve the mechanical stability and service life of the electrode thus prepared. If the thermal annealing temperature is too high, for example, higher than the above upper limit, the melting point of the porous carrier may be reached, which is limited by the thermal stability of the porous carrier and the intermediate layer; if the thermal annealing temperature is too low, for example, lower than the above lower limit, it is difficult to start the crystallization and phase transition process of the catalytic layer, and the intrinsic catalytic activity of the catalytic layer is limited.

[0044] Optionally, the temperature of the thermal annealing process may be, for example, 300°C, 350°C, 400°C, 450°C, or 500°C, or a range between any two of the above values.

[0045] In some embodiments, the time of the thermal annealing process is 5-20 min, which forms a relatively fast annealing process, can ensure sufficient crystallization and phase transition of the catalytic layer, while inhibiting excessive diffusion between the materials used in the above layers (for example, the intermediate diffusion of the catalytic layer into the porous carrier).

[0046] Optionally, the time of the thermal annealing process may be, for example, 5 min, 10 min, 15 min, or 20 min, or a range between any two of the above values.

[0047] In some embodiments, the pretreated porous carrier is prepared by subjecting the porous carrier to plasma treatment to obtain the pretreated porous carrier. The plasma treatment helps to clean and activate the inner and outer surfaces of the porous carrier, helps to improve the hydrophilicity of the inner and outer surfaces of the porous carrier, facilitates the subsequent deposition of the intermediate layer, and improves the adhesion strength between the intermediate layer and the porous carrier.

[0048] In some embodiments, the plasma used in the plasma treatment can be hydrogen plasma or ammonia plasma.

[0049] In some embodiments, the power of the plasma treatment can be 60-120 W, for example, can be 60 W, 80 W, 100 W or 120 W, etc., or a range composed between any two of the above values. The processing time can be 5-30 s, for example, can be 5 s, 10 s, 15 s, 20 s, 25 s or 30 s, etc., or a range composed between any two of the above values. In this way, the subsequent adhesion of the intermediate layer is more uniform, and the bonding strength between the intermediate layer and the porous carrier is improved.

[0050] In a specific embodiment, taking the porous carrier as a nickel foam, the intermediate layer as aluminum nitride, and the catalytic layer as molybdenum sulfide as an example, the preparation method of the electrode material can be as follows:

[0051] The nickel foam material is placed into a plasma enhanced atomic layer deposition device, and the surface of the nickel foam is treated with hydrogen plasma or ammonia plasma (taking ammonia plasma treatment as an example, which can be a mixture of ammonia gas and inert gas, and the inert gas can be nitrogen or argon); the treatment power of the plasma treatment can be 60-120 W, and the processing time can be 5-30 s.

[0052] According to an embodiment of another aspect of the present application, an electrode material is provided, which has a catalytic layer, an intermediate layer and a porous carrier arranged from outside to inside, and is prepared by the preparation method as described above.

[0053] According to an embodiment of the present application, the porous carrier of the electrode material of the present application provides good mechanical support; the intermediate layer can realize the connection between the porous carrier and the catalytic layer, so that electrons can pass through by quantum tunneling effect, which helps to optimize the injection efficiency and path of electrons from the porous carrier to the catalytic layer. When used as an electrode in the subsequent process, the Fermi level of the catalytic layer is more conducive to the adsorption and desorption of hydrogen in the electrolytic hydrogen production process.

[0054] In addition, the porous carrier (such as nickel foam), the insulating intermediate layer (such as beryllium oxide) and the catalytic layer (such as molybdenum sulfide semiconductor) form a structure similar to "metal-insulator-semiconductor", which can generate strong polarization and built-in electric field at the interface, which helps to promote the mass transfer and charge separation of reactants and / or products (such as water, hydrogen ions, hydrogen gas, etc.) at the interface in the subsequent application in, for example, electrolytic water hydrogen production, and further improves the catalytic efficiency.

[0055] It should be noted that the materials and functions of the porous carrier, the intermediate layer and the catalytic layer of the present application are consistent with the foregoing, and will not be repeated.

[0056] Further, the aluminum nitride or the aluminum oxide operates as an intermediate layer, through which the insulation and the tunneling characteristics are optimized for electron transfer. And through its high thermal conductivity, heat is dissipated, further improving the catalytic activity and stability of the catalytic layer (molybdenum sulfide).

[0057] In some embodiments, the thickness of the intermediate layer is 0.5-2 nm. The intermediate layer with insulating properties can allow controlled transmission of electrons between the porous carrier and the catalytic layer through quantum tunneling at the above thickness. Avoiding the complete insulation of the electrode, ensuring the establishment of the electrochemical reaction loop. At the same time, while retaining the tunneling performance, it can effectively block the free migration of carriers to prevent short circuits. If the thickness is too large, for example, exceeding the above upper limit, the tunneling probability will decrease exponentially, making the electrode resistance too large to work; if the thickness is too small, for example, below the lower limit, it is difficult to form a continuous intermediate layer, and it is difficult to provide effective physical isolation, so that the porous carrier and the catalytic layer will have undesirable atomic interdiffusion during annealing and / or reaction, etc.

[0058] Alternatively, the thickness of the intermediate layer may, for example, be 0.5 nm, 0.8 nm, 1 nm, 1.5 nm, or 2 nm, etc., or a range composed of any two of the above values, preferably 0.8-1 nm.

[0059] According to another aspect of the present application, a method for treating organic wastewater coupled with hydrogen production using the electrode material as described above is provided, comprising the following steps a-d.

[0060] In step a, hydrogen peroxide solution is added to the organic wastewater to obtain organic wastewater added with hydrogen peroxide solution.

[0061] In step b, under the irradiation of a UV lamp, using carbon material as the cathode and the electrode material as described above as the anode, a forward bias is applied to use the photo-Fenton reaction to preliminarily degrade the organic impurities in the organic wastewater.

[0062] In step c, the UV lamp is turned off, carbon material is used as the anode, and the electrode material as described above is used as the cathode, a reverse bias is applied, and electrolysis is carried out to produce hydrogen, while removing the degradation intermediates occupying the active sites on the electrode surface.

[0063] In step d, one step b and one step c constitute an operation cycle, and n sets of operation cycles are repeated to achieve deep removal of organic impurities in the organic wastewater; n is an integer greater than 1.

[0064] According to embodiments of the present invention, in the photoelectric Fenton reaction process, under ultraviolet light excitation, hydrogen peroxide (H2O2) reacts with active sites on the electrode surface to generate hydroxyl radicals (·OH), which can efficiently degrade organic impurities and significantly reduce chemical oxygen demand (COD). The applied positive bias voltage causes surface pre-activation of the catalyst layer. Taking molybdenum sulfide as an example, sulfur-rich vacancies and highly active edge sites are formed, providing favorable conditions for subsequent electrolytic hydrogen production. In the electrolytic hydrogen production process of the present invention, under the action of a reverse electric field, the degradation intermediates of organic impurities occupying active sites on the electrode surface detach from the electrode surface, re-exposing the active sites on the electrode surface, restoring the electrode's ability to generate ·OH, and effectively promoting the photoelectric Fenton reaction. The electrode material of the present invention, such as the one described above, can couple the degradation of organic impurities in the photoelectric Fenton reaction with electrolytic hydrogen production, and has the advantages of mutual promotion of the photoelectric Fenton reaction and electrolytic hydrogen production, energy saving, simple and easy processing, and recyclability, which is conducive to further promotion.

[0065] In addition, the present invention overcomes the dependence on membrane bioreactors in related technologies, and the present invention does not require adjustment of the pH value of organic wastewater or addition of ferrous inorganic salts, and can directly treat high-concentration COD organic wastewater, with advantages such as simple process route and fast treatment speed.

[0066] It should be noted that by coupling the photoelectric Fenton reaction with electrolytic hydrogen production, the defects of related technologies in electrolytic hydrogen production, such as passivation of electrode material surface, gradual decline in electrolytic hydrogen production effect and reduction of electrocatalytic activation sites, are overcome.

[0067] In some specific implementations, taking molybdenum sulfide as an example, the process of producing hydrogen by electrolysis is described in detail.

[0068] Electrolysis hydrogen production process:

[0069] The active sites of molybdenum sulfide can adsorb hydrogen ions and promote the formation of adsorbed hydrogen atoms (H*).

[0070] The hydrogen evolution process can be represented by the following reaction:

[0071] H + +e - →H*, where hydrogen ions (H) + Adsorbed electrons (e - (This forms adsorbed hydrogen atoms.)

[0072] H + +e - +H*→H2, where adsorbed hydrogen atoms combine with hydrogen ions to generate hydrogen gas (H2).

[0073] 2H*→H2, where two adsorbed hydrogen atoms directly combine to form hydrogen gas.

[0074] As shown in the above reaction process, the molybdenum sulfide can realize the efficient electrolytic hydrogen production process by adjusting the adsorption energy of hydrogen.

[0075] It can be understood that the catalytic mechanism of the molybdenum sulfide in the photoelectro-Fenton reaction is similar to the related art, and will not be described here.

[0076] In some embodiments, the operation period n may, for example, be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, etc., and the present application can be adjusted as needed according to the concentration of COD in the organic wastewater to be treated, which is not particularly limited.

[0077] In some embodiments, the ratio of the concentration of the hydrogen peroxide solution to the concentration of the chemical oxygen demand in the organic wastewater can be 0.05 to 0.4. In this way, deep degradation of organic impurities in the organic wastewater is achieved.

[0078] Alternatively, the ratio of the concentration of the hydrogen peroxide solution to the concentration of the chemical oxygen demand in the organic wastewater can be 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, or 0.4, etc., or a range formed between any two of the above ratios.

[0079] In some embodiments, the pressure of the forward bias applied can be 2 to 4 V, for example, 2 V, 3 V, or 4 V, etc. The current density of the reverse bias can be 1100 to 1300 mA / cm 2 , for example, 1100 mA / cm 2 , 1200 mA / cm 2 , or 1300 mA / cm 2 , etc., and the present application can be adjusted as needed according to the COD concentration of the organic wastewater to be treated, and the pressure and current density are not particularly limited.

[0080] In some embodiments, the time of applying the forward bias and / or the reverse bias can be 5 to 15 min, for example, 5 min, 10 min, or 15 min, etc., or a range formed between any two of the above values.

[0081] According to still another aspect of the present application, there is provided an organic wastewater treatment device, Figure 2 a cross-sectional view of the organic wastewater treatment device according to an embodiment of the present application is shown, as Figure 2 shown, the organic wastewater treatment device comprises an organic wastewater treatment tank 1 and a shell 2.

[0082] The organic wastewater treatment tank 1 can be a cylindrical closed structure, which comprises a first partition plate 11 and a second partition plate 12 arranged in a spaced sleeve manner from inside to outside, the shapes of the first partition plate 11 and the second partition plate 12 are hollow cylinders respectively, and the first partition plate 11 and the second partition plate 12 can be non-conductive materials such as plastics. The first partition plate 11 and the second partition plate 12 are arranged in a spaced manner, so as to divide the organic wastewater treatment tank 1 into a first wastewater tank 13, a second wastewater tank 14 and a third wastewater tank 15 arranged in sequence from inside to outside, the first wastewater tank 13 is located in the first partition plate 11, the second wastewater tank 14 is located between the first partition plate 11 and the second partition plate 12, and the third wastewater tank 15 is located between the second partition plate 12 and the shell 2. The material of the shell 2 can be a non-conductive material such as plastic.

[0083] The side wall of the first partition plate 11 has a plurality of first through holes 111, and the outer side of the first partition plate 11 is at least partially covered with the electrode material 16. It can be understood that the electrode material does not cover the first through holes 111, so that the organic wastewater can pass smoothly, and preferably the outer side of the side wall of the first partition plate 11 is entirely covered with the electrode material 16 except the first through holes 111. The side wall of the second partition plate 12 has second through holes 121, and the aperture of the second through holes 121 on the side of the third wastewater tank 15 is smaller than the aperture of the second through holes 121 on the side of the second wastewater tank 14. For example, as shown in Figure 2 , the design has an asymmetric aperture or a tapered hole. In this way, the residence time of the organic wastewater in the second wastewater tank 14 can be prolonged, and the organic wastewater has a long enough time to contact the catalytic layer on the surface of the electrode material in the second wastewater tank 14 (the core area for the photoelectro-Fenton reaction and the electrolytic hydrogen production reaction), so that the reaction is more sufficient, and the degradation rate of organic impurities and the hydrogen production rate are improved. In addition, such a structure can reduce the risk of mutual penetration of hydrogen and oxygen through the liquid to the opposite area, which is beneficial to separate collection, improves the gas recovery value and operation safety.

[0084] The top of the first wastewater tank 13 is provided with an organic wastewater inlet 131 adapted to receive the organic wastewater from the outside, and the top of the second wastewater tank 14 is provided with a hydrogen outlet 141 and an ultraviolet lamp placing opening 142. It can be understood that the ultraviolet lamp extends into the bottom of the second wastewater tank 14 through the ultraviolet lamp placing opening 142, so that the organic wastewater at different heights in the second wastewater tank 14 can fully perform the photoelectro-Fenton reaction. The hydrogen outlet 141 can be located in the ultraviolet lamp placing opening 142, or can be arranged at other positions as needed. The upper part of the third wastewater tank 13 is provided with an oxygen outlet 151, and the bottom of the third wastewater tank 13 is provided with a wastewater outlet 152.

[0085] The carbon material electrode 17 is arranged between the third wastewater tank 13 and the shell 2, and the carbon material electrode 17 can be a graphite electrode or the like.

[0086] According to the embodiment of the present application, under the irradiation of the ultraviolet lamp, the organic wastewater mixed with the hydrogen peroxide solution in the first wastewater pool 13 flows into the second wastewater pool 14 via the first through hole 111 to perform the photo-electric Fenton reaction, so as to preliminarily degrade the organic impurities in the organic wastewater. The partially degraded organic wastewater flows into the third wastewater pool 15 via the second through hole 121, and the organic wastewater in the second wastewater pool 14 and the third wastewater pool 15 performs the electrolytic hydrogen production reaction, the obtained hydrogen gas is discharged via the hydrogen gas outlet 141 of the second wastewater pool 14, the obtained oxygen gas is discharged via the oxygen gas outlet 151 of the third wastewater pool 15, and the purified organic wastewater is discharged via the wastewater outlet 152 of the third wastewater pool 15.

[0087] According to the embodiment of the present application, the photo-electric Fenton reaction and the electrolytic hydrogen production process are ingeniously coupled in the same device by the organic wastewater treatment device, the first wastewater pool 13 in the center provides a buffering effect, the second wastewater pool 14 in the reaction core area mainly performs the photo-electric Fenton degradation and the hydrogen production reaction, the third wastewater pool 15 performs the oxygen production reaction, and the purification of the organic wastewater is completed. The structure arranged in this way makes the organic wastewater in a one-way and orderly flow path, avoiding the safety hidden trouble caused by the mixing of hydrogen gas and oxygen gas. In addition, the hydrogen production electrode and the oxygen production electrode are separated in space, the purity of the gas collection is improved, and the availability of the recovered gas is improved. The organic impurities in the organic wastewater are degraded as "pollutants" by free radicals, and the degradation products further participate in the electrochemical hydrogen production, so that a large degree of material conversion and utilization is obtained.

[0088] In addition, the main body structure of the cylindrical organic wastewater treatment device is used, and the concentric circles formed by the first partition plate 11 and the second partition plate 12 are used for spatial partitioning, and the photo-electric Fenton and the electrolytic water hydrogen production are successfully integrated. In this way, not only the organic impurities are efficiently removed, the environmental protection purpose of deep purification is achieved, but also the high-value hydrogen gas and oxygen gas are produced synchronously in the treatment process, and the traditional consumption-type environmental protection treatment is changed into a production-type resource recovery process.

[0089] In some embodiments, the organic wastewater treatment device further comprises a pretreatment pool (not shown in the figure), which is suitable for mixing the hydrogen peroxide solution with the organic wastewater. The organic wastewater mixed with the hydrogen peroxide solution is introduced into the first wastewater pool 13 through the organic wastewater inlet 131.

[0090] In some embodiments, the organic wastewater treatment device further comprises a circulating pump (not shown in the figure), which is arranged between the pretreatment pool and the organic wastewater treatment pool 1, so as to reciprocally circulate the organic wastewater between the pretreatment pool and the organic wastewater treatment pool 1.

[0091] In some embodiments, the organic wastewater treatment device further comprises a support frame 3 located below the organic wastewater treatment tank 1, the support frame 3 being adapted to support the organic wastewater treatment tank 1, and the support frame 3 having a wastewater pipe outlet 31, the wastewater pipe outlet 31 being connected to the wastewater outlet 152 by a pipe, so that the purified organic wastewater discharged from the third wastewater tank is discharged through the pipe to the wastewater pipe outlet 31.

[0092] The present application is further illustrated by the following examples, figures, and related test experiments and results thereof. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to one of ordinary skill in the art that one or more embodiments can be practiced without these specific details. In other instances, well-known methods have not been described in detail in order to avoid unnecessarily obscuring the present application.

[0093] It should be noted that the following specific examples are only illustrative, and the scope of protection of the present application is not limited thereto. The chemicals and raw materials used in the following examples are commercially available or self-made by recognized processing methods.

[0094] Example 1

[0095] The present example 1 provides a method for treating organic wastewater of integrated circuits, the steps are as follows.

[0096] The preparation process of the electrode material includes the following steps.

[0097] After cleaning, the porous nickel foam is placed in a plasma-enhanced atomic layer deposition device. When the substrate temperature reaches 250℃, the surface of the porous nickel foam is treated by plasma. Ammonia plasma is used, and the plasma is composed of high-purity NH3 and argon. The treatment power of the plasma treatment is 75W, and the treatment time is 10s. Then N2 is introduced for purging for 35s. Thus, the pretreatment is completed.

[0098] Intermediate layer deposition: when the substrate temperature reaches 350℃, AlN thin film deposition is carried out. Trimethylaluminum (TMA) is selected as the Al source, and the introduction time is 1s, and N2 is purged for 5s. NH3 is selected as the N source, and the introduction time is 2s, and N2 is purged for 10s. The Al source and the N source are alternately grown for 10 times to complete the intermediate layer deposition, and the thickness is about 0.8nm.

[0099] MoS2 thin film deposition: MoCl5 is selected as the Mo source, and the introduction time is 3s, and N2 is purged for 15s. H2S is selected as the S source, and the introduction time is 3s, and N2 is purged for 20s. The Mo source and the S source are alternately grown for 50 times to complete the MoS2 thin film (catalytic layer) deposition.

[0100] The porous nickel foam after the deposition of the catalytic layer is placed into a hydrogen annealing furnace for heat annealing treatment, the annealing temperature is 300 DEG C, and the annealing time is 5 min, to obtain the electrode material.

[0101] The treatment process of the organic wastewater is as follows: the integrated circuit organic wastewater with high COD content (63 g / L) to be treated is introduced into a pretreatment tank, and hydrogen peroxide solution is added to ensure that the hydrogen peroxide content is 16.65 g / L; the pretreated organic wastewater is circulated back and forth between the pretreatment tank and the dual-function organic wastewater treatment tank by a circulating pump. The electrode material prepared in the application is used as the anode material for connecting the positive electrode of the power supply, and the graphite paper is used as the cathode material for connecting the negative electrode of the power supply. A forward bias of 3 V is applied to the organic wastewater, and an ultraviolet lamp is turned on at the same time, so that the organic matter in the organic wastewater is removed by a photo-Fenton reaction, and the treatment time is 10 min. Then the ultraviolet lamp is turned off, and a reverse bias is applied for electrolysis to produce hydrogen. In this process, the electrode material prepared in the application is connected to the negative electrode of the power supply, and the graphite paper is connected to the positive electrode of the power supply, and the current density is 1200 mA / cm2, and the treatment time is 10 min. The above-mentioned forward bias and reverse bias processes are alternately performed 9 times, and the total treatment time is 180 min, so that the organic impurities in the organic wastewater are removed.

[0102] Comparative Example 1

[0103] The preparation process of the electrode material of the present comparative example 1 is basically the same as that of Example 1, except that the present comparative example 1 does not form an intermediate layer, and directly deposits a molybdenum sulfide film on the porous nickel foam.

[0104] The treatment process of the organic wastewater of the present comparative example 1 is basically the same as that of Example 1, except that the electrode material prepared in the present comparative example 1 is used instead.

[0105] Comparative Example 2

[0106] The preparation process of the electrode material of the present comparative example 2 is the same as that of Example 1.

[0107] The treatment process of the organic wastewater is as follows: the integrated circuit organic wastewater with high COD content (63 g / L) to be treated is introduced into a pretreatment tank, and hydrogen peroxide solution is added to ensure that the hydrogen peroxide content is 16.65 g / L; the pretreated organic wastewater is circulated back and forth between the pretreatment tank and the dual-function organic wastewater treatment tank by a circulating pump. The electrode material prepared in the application is used as the anode material for connecting the positive electrode of the power supply, and the graphite paper is used as the cathode material for connecting the negative electrode of the power supply. A forward bias of 3 V is applied to the organic wastewater, and an ultraviolet lamp is turned on at the same time, so that the organic matter in the organic wastewater is removed by a photo-Fenton reaction, and the treatment time is 90 min.

[0108] Figure 3COD content of wastewater of Example 1, Comparative Example 1 and Comparative Example 2 over time. It can be seen from Figure 3

[0109] Example 2

[0110] The preparation process of the electrode material includes the following steps.

[0111] The cleaned porous nickel foam is placed into a plasma-enhanced atomic layer deposition device. When the substrate temperature reaches 250℃, the surface of the porous nickel foam is subjected to plasma treatment. The ammonia plasma is composed of high-purity NH3 and argon. The plasma treatment power is 120W, and the treatment time is 5s. Then, N2 is introduced for purging for 15s.

[0112] Intermediate layer deposition: when the substrate temperature reaches 350℃, AlN film deposition is performed. TMA is selected as the Al source, and the introduction time is 1s. N2 is introduced for purging for 5s. NH3 is selected as the N source, and the introduction time is 2s. N2 is introduced for purging for 10s. The Al source and the N source are alternately grown for 12 times to complete the deposition of the intermediate layer, and the thickness is about 1nm.

[0113] MoS2 film deposition: MoCl5 is selected as the Mo source, and the introduction time is 3s. N2 is introduced for purging for 15s. H2S is selected as the S source, and the introduction time is 3s. N2 is introduced for purging for 20s. The Mo source and the S source are alternately grown for 50 times to complete the deposition of the MoS2 film (catalytic layer).

[0114] The porous nickel foam after the deposition of the catalytic layer is placed into a hydrogen annealing furnace for heat annealing treatment. The annealing temperature is 500℃, and the annealing time is 20min. The electrode material is obtained.

[0115] ​The treatment process of the organic wastewater is as follows: the integrated circuit organic wastewater with low concentration COD content (220 mg / L) to be treated is introduced into a pretreatment tank, and hydrogen peroxide solution is added to ensure that the content of hydrogen peroxide is 25 mg / L; the pretreated organic wastewater is circulated back and forth between the pretreatment tank and the dual-function organic wastewater treatment tank through a circulating pump. The dual-function organic wastewater treatment tank uses the prepared electrode material as an anode material for connecting the positive pole of a power supply, and uses graphite paper as a cathode material for connecting the negative pole of the power supply and loading a forward bias of 1.5 V, and at the same time, an ultraviolet lamp is turned on to remove organic matters in the organic wastewater by a photo-Fenton reaction, and the treatment time is 5 min. Then, the ultraviolet lamp is turned off, and a reverse bias is applied for electrolysis to produce hydrogen, in this process, the prepared electrode material is connected to the negative pole of the power supply, the graphite paper is connected to the positive pole of the power supply, and a current density of 1000 mA / cm2 is loaded, and the treatment time is 5 min. Finally, the above forward bias and reverse bias processes are alternately performed for 6 times, and the total treatment time is 60 min, so as to remove organic impurities in the organic wastewater.

[0116] Comparative Example 3

[0117] The preparation process of the electrode material of the present comparative example 3 is basically the same as that of Example 2, except that the present comparative example 3 does not form an intermediate layer, and directly deposits a molybdenum sulfide film on the porous nickel foam.

[0118] The treatment process of the organic wastewater of the present comparative example 3 is basically the same as that of Example 2, except that the electrode material prepared by the present comparative example 3 is replaced.

[0119] Comparative Example 4

[0120] The preparation process of the electrode material of the present comparative example 4 is the same as that of Example 2.

[0121] The treatment process of the organic wastewater is as follows: the integrated circuit organic wastewater with low concentration COD content (220 mg / L) to be treated is introduced into a pretreatment tank, and hydrogen peroxide solution is added to ensure that the content of hydrogen peroxide is 25 mg / L; the pretreated organic wastewater is circulated back and forth between the pretreatment tank and the dual-function organic wastewater treatment tank through a circulating pump. The dual-function organic wastewater treatment tank uses the prepared electrode material as an anode material for connecting the positive pole of a power supply, and uses graphite paper as a cathode material for connecting the negative pole of the power supply and loading a forward bias of 1.5 V, and at the same time, an ultraviolet lamp is turned on to remove organic matters in the organic wastewater by a photo-Fenton reaction, and the treatment time is 5 min. Then, the ultraviolet lamp is turned off, and a reverse bias is applied for electrolysis to produce hydrogen, in this process, the prepared electrode material is connected to the negative pole of the power supply, the graphite paper is connected to the positive pole of the power supply, and a current density of 1000 mA / cm2 is loaded, and the treatment time is 5 min. Finally, the above forward bias and reverse bias processes are alternately performed for 6 times, and the total treatment time is 60 min, so as to remove organic impurities in the organic wastewater.

[0122] Figure 4 The curve graph of the COD content of the organic wastewater of Example 2, Comparative Example 3 and Comparative Example 4 of the present application with time is shown. From the curve graph, it can be seen that the COD content of the organic wastewater of Example 2 of the present application is the lowest, and the COD content of the organic wastewater of Comparative Example 3 is the highest. Figure 4It can be seen from the above that, for wastewater with an initial low COD content, embodiments 2, comparative example 3 and comparative example 4 all achieve good results, and all meet the municipal wastewater discharge standard. In general, the effect of the scheme of embodiment 2 of the present application is better.

[0123] Figure 5 A graph showing the change of the Tafel slope of embodiments 1, 2, comparative example 1 and comparative example 3 over time is shown. The Tafel slope describes the linear relationship between the overpotential of the electrode and the logarithm of the reaction current density, which is suitable for quantifying the degree of difficulty of the electrode reaction kinetics. A large slope value means that the electrode reaction is more difficult, and a large overpotential needs to be applied to drive the reaction to proceed; a small slope value means that the electrode reaction is relatively easy, and a small overpotential can significantly accelerate the reaction. From the above, it can be seen that the Tafel slope of the porous nickel foam electrode without an intermediate layer is higher than that of the porous nickel foam electrode with an intermediate layer, indicating that the hydrogen production capacity of the porous nickel foam electrode with an intermediate layer is relatively strong. Figure 5

[0124] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.​

Claims

1. A method for producing an electrode material, characterized by, The method comprises the following steps: An intermediate layer is deposited on a pretreated porous carrier by atomic layer deposition to obtain a porous carrier with the intermediate layer deposited on the surface of the porous carrier; A catalytic layer is deposited on the porous carrier with the intermediate layer deposited on the surface of the porous carrier by atomic layer deposition to obtain a porous carrier with the catalytic layer and the intermediate layer deposited on the surface of the porous carrier from outside to inside; The porous carrier with the catalytic layer and the intermediate layer deposited on the surface of the porous carrier from outside to inside is subjected to heat annealing treatment to obtain the electrode material; The material of the intermediate layer has a band gap of > 5 eV and a thermal conductivity of > 250 W / (m·K); the material of the intermediate layer comprises any one of aluminum nitride or beryllium oxide; The material of the catalytic layer comprises a two-dimensional transition metal chalcogenide compound; The pretreated porous carrier is prepared by the following method: The porous carrier is subjected to plasma treatment to obtain the pretreated porous carrier; The plasma used in the plasma treatment is hydrogen plasma or ammonia plasma, the power of the plasma treatment is 60-120 W, and the treatment time is 5-30 s; the porous carrier comprises a nickel foam.

2. The production method according to claim 1, characterized by, The temperature of the heat annealing treatment is 300-500 ℃, and the time is 5-20 min.

3. An electrode material, characterized by, The electrode material is prepared by the preparation method of claim 1 or 2.

4. The electrode material of claim 3, wherein, The thickness of the intermediate layer is 0.5-2 nm.

5. A method for treating organic wastewater coupled with hydrogen production using the electrode material according to claim 3 or 4, characterized in that, The method comprises the following steps a-d: Step a: adding a hydrogen peroxide solution to the organic wastewater to obtain the organic wastewater added with the hydrogen peroxide solution; Step b: under the irradiation of an ultraviolet lamp, using a carbon material as a cathode and the electrode material as an anode, applying a forward bias, and using a photoelectro-Fenton reaction to preliminarily degrade organic impurities in the organic wastewater; Step c: turning off the ultraviolet lamp, using the carbon material as an anode and the electrode material as a cathode, applying a reverse bias, and electrolyzing to produce hydrogen while removing degradation intermediates occupying active sites on the electrode surface; Step d: taking one step b and one step c as one operation cycle, repeating n groups of operation cycles to achieve deep removal of organic impurities in the organic wastewater; n is an integer greater than 1.

6. The method of claim 5, wherein, The concentration ratio of the hydrogen peroxide solution to the chemical oxygen demand concentration in the organic wastewater is 0.05-0.

4.

7. An organic wastewater treatment device, characterized by comprising: The organic wastewater treatment tank and the shell are included; The first baffle and the second baffle are sequentially and separately arranged in the organic wastewater treatment tank, and the first baffle and the second baffle divide the organic wastewater treatment tank into a first wastewater tank, a second wastewater tank and a third wastewater tank; the first wastewater tank is located in the first baffle, the second wastewater tank is located between the first baffle and the second baffle, and the third wastewater tank is located between the second baffle and the shell; The first baffle has a first through hole, and the outer side of the first baffle is coated with the electrode material of claim 3 or 4; the second baffle has a second through hole, and the pore size of the second through hole on the side of the third wastewater tank is smaller than the pore size of the second through hole on the side of the second wastewater tank; The top of the first wastewater pool is provided with an organic wastewater inlet, and the top of the second wastewater pool is provided with a hydrogen gas outlet and an ultraviolet lamp placing opening; the upper part of the third wastewater pool is provided with an oxygen gas outlet, and the bottom of the third wastewater pool is provided with a wastewater outlet; A carbon material electrode is arranged between the third wastewater pool and the shell; Under the irradiation of the ultraviolet lamp, the organic wastewater mixed with the hydrogen peroxide solution in the first wastewater pool flows into the second wastewater pool through the first through hole to perform a photoelectric Fenton reaction, so as to preliminarily degrade the organic impurities; part of the organic wastewater after the preliminary degradation flows into the third wastewater pool through the second through hole, the organic wastewater in the second wastewater pool and the third wastewater pool performs an electrolytic hydrogen production reaction, the obtained hydrogen gas is discharged through the hydrogen gas outlet of the second wastewater pool, the obtained oxygen gas is discharged through the oxygen gas outlet of the third wastewater pool, and the purified organic wastewater is discharged through the wastewater outlet of the third wastewater pool.

8. The organic wastewater treatment device according to claim 7, wherein The organic wastewater treatment device further comprises a support frame arranged below the organic wastewater treatment pool, the support frame being suitable for supporting the organic wastewater treatment pool, and the support frame being provided with a wastewater pipe outlet connected with the wastewater outlet through a pipeline.

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