阅读说明：本技术 一种三维Fe-Mo-S催化剂负载的多孔碳电极的制备方法及其应用 (Preparation method and application of porous carbon electrode loaded by three-dimensional Fe-Mo-S catalyst ) 是由 黄理志 杨攀 郭景宜 陈若仪 刘嘉玮 冯健恒 万泓廷 唐嘉怡 曾洪涛 于 2020-11-17 设计创作，主要内容包括：本发明属于电芬顿阴极材料的合成及电芬顿水处理技术领域。一种三维Fe-Mo-S催化剂负载的多孔碳电极的制备方法,其特征在于包括如下步骤：步骤S1：首先将洁净的碳纤维毡在浓硝酸中浸泡,随后清洗碳纤维毡至中性；步骤S2：分别称量0.3475～1.0425g的FeSO-4·7H-2O、0.3024～0.9072g的Na-2MoO-4·2H-2O和1.5993～4.7979g的L-Cys氨基酸加水溶于反应釜内胆中,超声、搅拌,并定容至200mL；步骤S3：放入洗净的碳纤维毡；步骤S4：将反应釜放入电热鼓风烘箱中进行合成；步骤S5：清洗、烘干,获得产品。通过水热法将Fe-Mo-S催化剂负载在碳纤维毡上,高效地产生羟基自由基,进而氧化降解污水中的有机污染物,催化效果显著；且涉及的制备工艺简单,材料价格较低。(The invention belongs to the technical field of synthesis of electro-Fenton cathode materials and electro-Fenton water treatment. A preparation method of a porous carbon electrode loaded by a three-dimensional Fe-Mo-S catalyst is characterized by comprising the following steps: step S1: firstly, soaking a clean carbon fiber felt in concentrated nitric acid, and then cleaning the carbon fiber felt to be neutral; step S2: 0.3475-1.0425 g of FeSO is respectively weighed 4 ·7H 2 O, 0.3024-0.9072 g of Na 2 MoO 4 ·2H 2 Dissolving O and 1.5993-4.7979 g of L-Cys amino acid in water in an inner container of a reaction kettle, and carrying out ultrasonic and stirringAnd fixing the volume to 200 mL; step S3: putting the cleaned carbon fiber felt; step S4: putting the reaction kettle into an electric heating blast oven for synthesis; step S5: cleaning and drying to obtain the product. The Fe-Mo-S catalyst is loaded on the carbon fiber felt by a hydrothermal method, hydroxyl radicals are efficiently generated, organic pollutants in sewage are further oxidatively degraded, and the catalytic effect is remarkable; and the related preparation process is simple, and the material price is lower.)

1. A preparation method of a porous carbon electrode loaded by a three-dimensional Fe-Mo-S catalyst is characterized by comprising the following steps:

step S1: firstly, soaking a clean carbon fiber felt in concentrated nitric acid, and then cleaning the carbon fiber felt to be neutral;

step S2: 0.3475-1.0425 g of FeSO is respectively weighed₄·7H₂O, 0.3024-0.9072 g of Na₂MoO₄·2H₂O and 1.5993-4.7979 g of L-Cys amino acid are added with water and dissolved in the inner container of the reaction kettleUltrasonically treating and stirring until the solution is fully dissolved to obtain transparent liquid, and fixing the volume to 200mL to obtain solution;

step S3: transferring the solution into a 300mL hydrothermal synthesis reaction kettle liner, and putting the carbon fiber felt cleaned in the step S1 into the hydrothermal synthesis reaction kettle liner;

step S4: putting the reaction kettle into an electric heating blast oven for synthesis, and naturally cooling to room temperature after synthesis;

step S5: taking out the prepared carbon fiber felt, and respectively using 1M H₂SO₄Washing with alcohol and ultrapure water for many times; and drying the cleaned material to obtain the porous carbon electrode loaded by the three-dimensional Fe-Mo-S catalyst.

2. The method for preparing a three-dimensional Fe-Mo-S catalyst-supported porous carbon electrode according to claim 1, wherein: the FeSO₄·7H₂O、Na₂MoO₄·2H₂O, L-Cys amino acid total molar concentration is 0.008-0.03 mol/L.

3. The method for preparing a three-dimensional Fe-Mo-S catalyst-supported porous carbon electrode according to claim 1, wherein: in step S1: and soaking the clean carbon fiber felt in concentrated nitric acid for 12 hours.

4. The method for preparing a three-dimensional Fe-Mo-S catalyst-supported porous carbon electrode according to claim 1, wherein: in step S4: the synthesis temperature is 200 ℃, and the synthesis time is 24 h.

5. The method for preparing a three-dimensional Fe-Mo-S catalyst-supported porous carbon electrode according to claim 1, wherein: in step S5: the washed material was dried at 65 ℃ for 12 h.

6. Use of a three-dimensional Fe-Mo-S catalyst supported porous carbon electrode according to claim 1, characterized in that: the application in the photoelectric combined water treatment device is as follows: the porous carbon electrode loaded by the three-dimensional Fe-Mo-S catalyst is embedded into the vacancy of the cathode chamber, then the ion exchange membrane and the anode chamber component are sequentially overlapped, finally the reactor main body is hermetically connected by mounting screws, when the cathode chamber component is overlapped, the porous carbon electrode loaded by the three-dimensional Fe-Mo-S catalyst needs to be placed in the cathode chamber, and then the cathode plate is covered.

7. Use of a three-dimensional Fe-Mo-S catalyst supported porous carbon electrode according to claim 6, characterized in that: the photoelectric combined water treatment device comprises a reactor main body, a photoelectric complementary system, a pressure reduction module, a small water pump and a water inlet and outlet control system.

8. Use of a three-dimensional Fe-Mo-S catalyst supported porous carbon electrode according to claim 7, characterized in that: the photoelectric complementary system comprises a solar panel, a controller and a storage battery; solar panel assembles on the sunlight tracks the base, can guarantee automatically that sunshine and solar panel are perpendicular according to the position of sun.

9. Use of a three-dimensional Fe-Mo-S catalyst supported porous carbon electrode according to claim 7, characterized in that: the water inlet and outlet control system comprises an online water quality monitor, a valve control system and a submersible pump; the submersible pump pumps sewage to be treated in the wastewater pool into the reactor for treatment, once the water quality monitor detects that the quality of the effluent reaches the standard, the valve control system opens the drain valve to drain, and simultaneously the valve control system opens the water inlet valve to introduce the sewage to be treated with the same drainage quantity to the wastewater pool and enter a new treatment process.

10. Use of a three-dimensional Fe-Mo-S catalyst supported porous carbon electrode according to claim 7, characterized in that: the carbon felt of the cathode chamber is attached with a catalyst, so that the electro-Fenton reaction activity is enhanced, and high-concentration organic wastewater is efficiently treated.

Technical Field

The invention belongs to the technical field of synthesis of electro-Fenton cathode materials and electro-Fenton water treatment, and particularly relates to a preparation method of a porous carbon electrode loaded by a three-dimensional Fe-Mo-S catalyst and application of the porous carbon electrode in a photoelectric combined water treatment device.

Background

The carbon fiber felt (porous carbon) is a felt-like porous material prepared by carbonizing a high polymer at high temperature, has rich raw materials, low price, easy production, looseness, porosity and large surface area, and has good chemical stability and conductivity. Therefore, the catalyst can be used as an ideal carrier of the catalyst. The porous structure results in more exposed catalytically active edge sites.

The rate of the redox reaction determines the operating efficiency of the cell, and the reaction rate is determined by the catalyst. Since the overpotential of the oxidation-reduction reaction (ORR) of the cathode is much greater than that of the oxidation reaction of the anode, and the electrode reaction of the cathode is more difficult to perform than that of the anode, the research on the catalyst of the cathode has a deeper significance, and the type of the supported catalyst is the key for improving the efficiency of the electro-fenton reaction. The metal ions are common homogeneous catalysts, and although the catalytic efficiency is high, the metal ions have the defects of incapability of recycling, easy secondary pollution, easy generation of metal mud and the like. The heterogeneous metal catalyst is relatively stable in the reaction process and easy to recycle, but the activity is relatively low and the selectivity is relatively poor, the catalysis process only occurs on the surface of the catalyst, and metal atoms in the material do not participate in the reaction; the traditional nanometer heterogeneous catalyst has the defects of difficult uniform reaction active center and poor selectivity.

Monatomic catalysts (SACs) combine the advantages of heterogeneous catalysts and homogeneous catalysts, while making up for the deficiencies between them: compared with a heterogeneous catalyst, the catalyst improves the atom utilization rate, has uniform active sites and adjustable electronic environment, and realizes high catalytic activity and selectivity; compared with a homogeneous catalyst, the catalyst has higher stability and better recyclability; compared with the traditional nano and block catalysts, the SACs have the advantages of high activity, good selectivity, 100% atom utilization rate and the like, and the risk of metal ion dissolution is reduced. Experimental and theoretical studies have shown that when the particle dispersion reaches monoatomic size, many new properties are induced, such as dramatically increased surface free energy, quantum size effects, unsaturated coordination environment and metal-matrix interactions (SMSI) can cause electronic structure changes. The catalytic active sites of the catalyst are exposed to the maximum extent, and the utilization efficiency of the catalyst is improved, so that the cost of the catalyst is reduced.

Meanwhile, in order to efficiently treat high-concentration organic wastewater, the electrocatalytic oxidation technology has been rapidly developed in recent years. The electrochemical method for treating the wastewater has the characteristics of easy control, no pollution or little pollution, high flexibility, economy and the like, and is a research hotspot in the current environmental science and engineering fields. The high-concentration wastewater has complex water quality and high organic matter content, and the ideal treatment effect is often difficult to achieve if the high-concentration wastewater is treated by a single physical-chemical method, a membrane method or other traditional treatment methods. The electro-Fenton oxidation can be operated at normal temperature and normal pressure, and the electrochemical method is used for generating Fe²⁺And H₂O₂As the Fenton reagent, the method has the advantages of low chemical agent cost, simple equipment, convenient operation, low investment and running cost, small occupied area, little sludge amount, environmental compatibility and the like.

However, the current electro-Fenton technology should be applied in practiceThe power consumption is higher during use, which causes higher operation cost; the traditional iron electrode has a common effect as a catalytic electrode, an anode iron plate can corrode and dissolve out iron ions in the operation process, the electrode needs to be replaced regularly, the dissolved out iron ions can generate a large amount of iron mud waste residues, the iron mud contains a large amount of toxic substances, the iron mud must be treated as hazardous waste, and the treatment cost is extremely high; however, in the conventional Fenton method, additional H is required₂O₂And Fe²⁺Thereby increasing the cost, generating a large amount of ferric hydroxide sludge by-products which need secondary treatment in the reaction process, and adding Fe at the beginning of the reaction²⁺Will be converted into Fe³⁺Slowing down the reaction rate. In addition, the traditional flat plate electrode has smaller specific surface area and poorer treatment effect, and particularly has undesirable treatment effect when the conductivity of the wastewater is lower.

Disclosure of Invention

Aiming at the problems, the invention provides a preparation method of a porous carbon electrode (hereinafter referred to as three-dimensional Fe-Mo-S carbon felt electrode) loaded by a three-dimensional Fe-Mo-S catalyst and an application of the porous carbon electrode in a photoelectric combined water treatment device. The Fe-Mo-S catalyst is loaded on the carbon fiber felt by a hydrothermal method, hydroxyl radicals are efficiently generated, organic pollutants in sewage are further oxidatively degraded, and the catalytic effect is remarkable; and the related preparation process is simple, and the material price is lower.

In order to achieve the purpose, the invention adopts the technical scheme that the preparation method of the porous carbon electrode loaded by the three-dimensional Fe-Mo-S catalyst is characterized by comprising the following steps of:

step S1: firstly, soaking a clean carbon fiber felt in concentrated nitric acid for 12 hours to enable the surface of the carbon fiber felt to generate oxygen-containing functional groups and increase the hydrophilicity of the carbon fiber felt, and then cleaning the carbon fiber felt to be neutral;

step S2: 0.3475-1.0425 g of FeSO is respectively weighed₄·7H₂O (ferrous sulfate heptahydrate) 0.3024-0.9072 g of Na₂MoO₄·2H₂O (sodium molybdate dihydrate) and 1.5993-4.7979 g of L-Cys amino acid (L-cysteine) are added with water and dissolved in an inner container of a reaction kettle, ultrasonic treatment and stirring are carried out until the L-Cys amino acid (L-cysteine) is fully dissolved to obtain transparent liquid, and constant volume is carried outObtaining a solution when the volume is 200 mL;

step S3: transferring the solution into a 300mL hydrothermal synthesis reaction kettle liner, and putting the carbon fiber felt cleaned in the step S1 into the hydrothermal synthesis reaction kettle liner;

step S4: putting the reaction kettle into an electric heating blast oven for synthesis, wherein the synthesis temperature is 200 ℃, the synthesis time is 24 hours, and naturally cooling to room temperature after the synthesis is finished;

step S5: taking out the prepared carbon fiber felt, and respectively using 1M H₂SO₄Washing with alcohol and ultrapure water for several times (e.g. 3 times); and drying the cleaned material at 65 ℃ for 12h to obtain the porous carbon electrode loaded with the three-dimensional Fe-Mo-S catalyst (or the finished product of the porous carbon electrode loaded with the Fe-Mo-S catalyst).

The volume concentration of the concentrated nitric acid is 96-98%.

The FeSO₄·7H₂O (ferrous sulfate heptahydrate), Na₂MoO₄·2H₂The total molar concentration of O (sodium molybdate dihydrate) and L-Cys amino acid is 0.008-0.03 mol/L.

The alcohol is 98-99.9% ethanol.

The method is applied to the reaction principle of electro-Fenton reaction, the specific reaction mechanism is shown in reactions (1) to (4), and the dissolved oxygen O in the wastewater₂Reduction to H at the cathode₂O₂And further generates a hydroxyl radical (. OH) by the catalytic action of Fe-Mo-S:

">" in the reaction formula represents the catalyst surface, > Fe in Fe-Mo-S²⁺And > Mo⁴⁺Can both activate H₂O₂Production of OH, > Fe³⁺Can be > Mo⁴⁺Reduction to produce new > Fe²⁺While > Fe²⁺And > Mo⁴⁺Can also be generated at the cathode through electrochemical reduction, and finally realizes the Fe-Mo bimetal synergetic electrocatalysis decontamination process.

The application of the porous carbon electrode loaded by the three-dimensional Fe-Mo-S catalyst is characterized by being applied to a photoelectric combined water treatment device: embedding a porous carbon electrode loaded by a three-dimensional Fe-Mo-S catalyst into a vacancy of a cathode chamber, then sequentially overlapping an ion exchange membrane and an anode chamber component, and finally installing a screw to hermetically connect a reactor main body, wherein the connection sequence can greatly avoid the damage of a carbon felt electrode caused by friction; when the cathode chamber components are stacked, the porous carbon electrode loaded by the three-dimensional Fe-Mo-S catalyst needs to be placed in the cathode chamber, then the cathode plate is covered, and meanwhile, the situation that fibers of the carbon felt stretch into gaps of the cathode chamber is avoided.

The photoelectricity allies oneself with water treatment facilities is an electro-catalytic reaction unit, including reactor main part, photoelectricity complementary system, step-down module, small-size water pump and business turn over water control system.

The reactor is sequentially assembled by an MMO anode, a leakage-proof rubber mat, a corrosion-resistant plastic frame, a leakage-proof rubber mat, a cationic membrane, a leakage-proof rubber mat, a corrosion-resistant plastic frame with a three-dimensional Fe-Mo-S carbon felt electrode arranged in the middle, a rubber mat and a graphite cathode, wherein the order is not required to be positive and negative, and the reactor is sequentially assembled.

The plastic used by the corrosion-resistant plastic frame is polyvinylidene fluoride, polypropylene or other thermoplastic plastics, the middle of the corrosion-resistant plastic frame is provided with a flow guide hole for playing a flow guide role, and a three-dimensional Fe-Mo-S carbon felt electrode is arranged in the frame close to the graphite cathode.

The mixed metal oxide anode, the leak-proof rubber mat and the graphite cathode in the reactor are all provided with an up-down inclined hole.

The reactor clamps the side holes of the cathode plate and the anode plate through alligator clips on the leads so that the reactor is connected with the anode and the cathode of the power supply, the upper part of the anode plate is provided with a water inlet, and the lower part of the cathode plate is provided with a water outlet.

The reactor is cooperatively powered by a storage battery, solar energy and a municipal power grid, wherein the solar energy is collected by a solar panel and generates electric energy which is output in the form of voltage.

The photoelectric complementary system comprises a solar panel, a controller and a storage battery; the solar panel is connected to the controller, one group of wires of the controller is directly connected with the direct current load, and the other group of wires of the controller is connected with the storage battery and is connected to the direct current load through the storage battery; the municipal power grid is connected to a dc load through a rectifier. Solar panel assembles on sunlight tracks the base, can adjust solar panel and perpendicular with sunshine in real time according to the position of sun automatically, acquires maximum light intensity, reduces the energy consumption.

The voltage reduction module is composed of a voltage reducer and is used for reducing the voltage generated by the solar panel to reach the actual required voltage of the reaction device.

The water inlet and outlet control system comprises an online water quality monitor, a valve control system and a submersible pump; the submersible pump pumps sewage to be treated in the wastewater pool into the reactor for treatment, once the water quality monitor detects that the quality of the effluent reaches the standard, the valve control system opens the drain valve to drain, and simultaneously the valve control system opens the water inlet valve to introduce the sewage to be treated with the same drainage quantity to the wastewater pool and enter a new treatment process.

The carbon felt of the cathode chamber is attached with a catalyst, so that the electro-Fenton reaction activity is enhanced, and high-concentration organic wastewater is efficiently treated.

The water flow sequence of the reactor is that water enters from a small hole at the upper end of the MMO anode, sequentially passes through the rubber mat and the corrosion-resistant plastic frame, is guided by the corrosion-resistant plastic frame and then forms anode outlet water at the lower end of the MMO anode through the rubber mat, the anode outlet water enters the reactor from a small hole at the upper end of the graphite cathode through the corrosion-resistant water delivery rubber hose, the water flow sequentially passes through the rubber mat and the Fe-carbon felt cathode and then is guided by the corrosion-resistant plastic frame, the water flow passes through the rubber mat, and forms cathode outlet water at a small hole below the graphite cathode, namely finally treated clean water.

The water inlet and outlet of the reactor is controlled by a water inlet and outlet control system, and the water inlet and outlet control system comprises a water quality online monitoring system and a valve control system.

The water quality on-line monitoring system is an aqueous solution on-line COD sensor and comprises a sensor and a probe, wherein the sensor consists of a control key, a display screen, a heat dissipation hole, a shell and a wiring terminal.

The valve control system is an electric valve for controlling the opening and closing of the water solution on-line COD sensor.

The three-dimensional carbon felt is a felt-like material prepared by carbonizing a high polymer at high temperature, is loose and porous, and has good chemical stability and electrical conductivity.

The device disclosed by the invention adopts a modular design, all parts are cooperatively matched, the collocation is flexible, the automation degree is high, the flow is simple, and the solar energy and the municipal power grid are cooperatively used for supplying power, so that the energy consumption is low. In addition, the porous carbon felt electrode loaded by three-dimensional Fe-Mo-S is adopted, so that the activity of electro-Fenton reaction is enhanced, the water treatment effect is good, the environment is protected, and the secondary pollution is small.

The invention has the following remarkable effects:

1. the catalyst is loaded on the two-dimensional carrier in a monatomic form, the monatomic catalyst has high activity, the addition amount can be properly reduced, and the cost is lower.

2. The efficiency of generating hydroxyl free radicals (OH) by the device is enhanced through Fe-Mo bimetallic concerted catalysis, and the mineralization and detoxification of refractory organic pollutants are realized by utilizing the extremely strong oxidation activity of OH, so that the reaction rate and the yield are improved, and the catalytic effect is obvious.

3. The invention can effectively reduce the product precipitation in the electro-Fenton reaction and avoid the phenomena of secondary pollution and resource waste.

4. The invention reduces the energy consumption of the unit sewage treatment of the device through the innovations on the catalytic material and the catalytic mechanism, further reduces the energy consumption by combining the power supply of the solar panel, and saves the operation cost by reducing the operation power consumption.

5. The invention realizes the automation of the whole water treatment process through the sunlight tracker, the water quality on-line monitoring system, the water inlet and outlet control system and the like, does not need manual participation and greatly saves the labor cost.

6. The invention adopts a mode of cooperatively supplying power by the storage battery, the solar energy and the municipal power grid, ensures that the power can be continuously supplied in the power failure accident, and reduces the accident cost of overstocked toxic wastewater in a factory.

Drawings

FIG. 1 is a scanning electron microscope image of a three-dimensional Fe-Mo-S carbon felt obtained in the present invention;

FIG. 2 is a spherical aberration corrected high resolution transmission electron microscope image of the three-dimensional Fe-Mo-S carbon felt obtained in the invention, wherein Fe is in monoatomic dispersion on a two-dimensional MoS2 limited-area carrier, and the average distance is 2 nm;

fig. 3 is an overall composition model diagram of a photoelectric combined water treatment device (or called a photoelectric-driven three-dimensional electro-fenton water treatment device) provided by the invention;

FIG. 4 is a schematic structural view of the reactor body in FIG. 3;

fig. 5 is a data diagram of experiments performed by a photoelectric combined water treatment device (or a photoelectric-driven three-dimensional electro-fenton water treatment device) according to examples 3 and 4;

fig. 6 is a data diagram of the photoelectric combined water treatment device (or called a photoelectric-driven three-dimensional electro-fenton water treatment device) provided by the invention for the removal rate of the simulated wastewater COD under different plate voltages;

fig. 7 is a data diagram of the photoelectric combined water treatment device (or called a photoelectric-driven three-dimensional electro-fenton water treatment device) provided by the invention for respectively measuring the COD removal rates of the simulated printing and dyeing wastewater and the actual industrial wastewater under different plate voltages.

Detailed Description

The salient features and significant improvements of the present invention are further clarified by the following examples, which are intended to be illustrative only and not limiting in any way.

Example 1

A preparation method of a porous carbon electrode loaded by a three-dimensional Fe-Mo-S catalyst comprises the following steps:

1) firstly, soaking a clean carbon fiber felt (or called carbon felt, porous carbon and three-dimensional carbon felt) in concentrated nitric acid for 12 hours to enable the surface of the carbon fiber felt to generate oxygen-containing functional groups and increase the hydrophilicity of the oxygen-containing functional groups, and then cleaning the carbon fiber felt to be neutral;

2) 0.3475 g of FeSO was weighed in each case₄·7H₂O (ferrous sulfate heptahydrate), 0.3024 g Na₂MoO₄·2H₂Dissolving O (sodium molybdate dihydrate) and 1.5993 g of L-Cys amino acid (L-cysteine) in water in an inner container of a reaction kettle, performing ultrasonic treatment and stirring until the solution is fully dissolved to obtain transparent liquid, and fixing the volume to 200mL to obtain solution;

3) transferring the solution into a 300mL hydrothermal synthesis reaction kettle liner, and putting the carbon fiber felt into the kettle;

4) putting the reaction kettle into an electric heating blast oven for synthesis, wherein the synthesis temperature is 200 ℃, the synthesis time is 24 hours, and naturally cooling to room temperature after the synthesis is finished;

5) taking out the prepared carbon fiber felt, and respectively using 1M H₂SO₄Washing with alcohol and ultrapure water for 3 times; and drying the cleaned material at 65 ℃ for 12h to obtain the porous carbon electrode loaded with the three-dimensional Fe-Mo-S catalyst (or called a porous carbon electrode finished product loaded with the Fe-Mo-S catalyst, or called a three-dimensional Fe-Mo-S carbon felt finished product). And characterizing by methods such as a scanning electron microscope and a spherical aberration electron microscope, and the obtained images are shown in fig. 1 and fig. 2.

Example 2

A preparation method of a porous carbon electrode loaded by a three-dimensional Fe-Mo-S catalyst comprises the following steps:

1) firstly, soaking a clean carbon fiber felt in concentrated nitric acid for 12 hours to enable the surface of the carbon fiber felt to generate oxygen-containing functional groups and increase the hydrophilicity of the oxygen-containing functional groups, and then cleaning the carbon fiber felt to be neutral;

2) 0.8 g of FeSO was weighed separately₄·7H₂O (ferrous sulfate heptahydrate), 0.6 g of Na₂MoO₄·2H₂Dissolving O (sodium molybdate dihydrate) and 3.0 g of L-Cys amino acid in water in an inner container of a reaction kettle, performing ultrasonic treatment and stirring until the L-Cys amino acid is fully dissolved to obtain transparent liquid, and metering the volume to 200mL to obtain a solution;

3) transferring the solution into a 300mL hydrothermal synthesis reaction kettle liner, and putting the carbon fiber felt into the kettle;

4) putting the reaction kettle into an electric heating blast oven for synthesis, wherein the synthesis temperature is 200 ℃, the synthesis time is 24 hours, and naturally cooling to room temperature after the synthesis is finished;

5) taking out the prepared carbon fiber felt, and respectively using 1M H₂SO₄Washing with alcohol and ultrapure water for 3 times; and drying the cleaned material at 65 ℃ for 12h to obtain the three-dimensional Fe-Mo-S catalyst loaded porous carbon electrode. And characterizing by methods such as a scanning electron microscope and a spherical aberration electron microscope, and the obtained images are shown in fig. 1 and fig. 2.

Example 3

A preparation method of a porous carbon electrode loaded by a three-dimensional Fe-Mo-S catalyst comprises the following steps:

1) firstly, soaking a clean carbon fiber felt in concentrated nitric acid for 12 hours to enable the surface of the carbon fiber felt to generate oxygen-containing functional groups and increase the hydrophilicity of the oxygen-containing functional groups, and then cleaning the carbon fiber felt to be neutral;

2) 1.0425g of FeSO were weighed respectively₄·7H₂O (ferrous sulfate heptahydrate), 0.9072g of Na₂MoO₄·2H₂Dissolving O (sodium molybdate dihydrate) and 4.7979g of L-Cys amino acid in water in an inner container of a reaction kettle, performing ultrasonic treatment and stirring until the L-Cys amino acid is fully dissolved to obtain transparent liquid, and metering the volume to 200mL to obtain a solution;

3) transferring the solution into a 300mL hydrothermal synthesis reaction kettle liner, and putting the carbon fiber felt into the kettle;

4) putting the reaction kettle into an electric heating blast oven for synthesis, wherein the synthesis temperature is 200 ℃, the synthesis time is 24 hours, and naturally cooling to room temperature after the synthesis is finished;

5) taking out the prepared carbon fiber felt, and respectively using 1M H₂SO₄Washing with alcohol and ultrapure water for 3 times; and drying the cleaned material at 65 ℃ for 12h to obtain the three-dimensional Fe-Mo-S catalyst loaded porous carbon electrode. And characterizing by methods such as a scanning electron microscope and a spherical aberration electron microscope, and the obtained images are shown in fig. 1 and fig. 2.

Example 4

The application of the porous carbon electrode supported by the three-dimensional Fe-Mo-S catalyst in the examples 1 to 3 is applied to a water treatment device for photoelectric combination: the porous carbon electrode loaded by the three-dimensional Fe-Mo-S catalyst is embedded into the vacancy of the cathode chamber, then the ion exchange membrane and the anode chamber component are sequentially superposed, and finally the reactor main body is hermetically connected by mounting screws, so that the damage of the carbon felt electrode caused by friction can be greatly avoided by the connection sequence. When the cathode chamber components are stacked, the porous carbon electrode loaded by the three-dimensional Fe-Mo-S catalyst needs to be placed in the cathode chamber, then the cathode plate is covered, and meanwhile, the situation that fibers of the carbon felt stretch into gaps of the cathode chamber is avoided.

The photoelectricity union water treatment device (electrochemical device) can be used as water treatment equipment of industrial wastewater, can remarkably reduce the content of organic matters in high-concentration organic wastewater, and is low in cost, more economical and efficient. The technical scheme is as follows:

as shown in fig. 3, the photoelectric water treatment device (or called photoelectric-driven three-dimensional electro-fenton water treatment device) is an electro-catalytic reaction device, and includes a reactor main body, a photoelectric complementary system, a pressure reduction module, a small water pump, and a water inlet and outlet control system.

The photoelectric complementary system comprises a solar panel, a controller and a storage battery; the solar panel is connected to the controller, one group of wires of the controller is directly connected with the direct current load, and the other group of wires of the controller is connected with the storage battery and is connected to the direct current load through the storage battery; the municipal power grid is connected to a dc load through a rectifier. Solar panel assembles on sunlight tracks the base, can adjust solar panel and perpendicular with sunshine in real time according to the position of sun automatically, acquires maximum light intensity, reduces the energy consumption. The storage battery provides stable voltage for the subsequent reactor to use.

The water inlet and outlet control system comprises an online water quality monitor (namely an online water quality monitoring system), a valve control system, a water pump (a submersible pump) and a pipeline; the rear part of the reactor is connected with a water tank, a probe of an online water quality detector is submerged below the water surface of the water tank, and meanwhile, the online water quality detector can detect relevant indexes and transmit data to a valve control system; the water tank has two water outlet pipes, one is clear water pipe for discharging water up to standard, the other is return pipe for returning and retreating water up to standard, electric valve K₂Is arranged on the clean water pipe and is provided with an electric valve K₃Mounted on return conduits, electric valves K₁The water inlet pipe is arranged between the reactor and the water pump, and the water pump is arranged in the sewage pool; the three electric valves are all connected with a valve controller, and the valve controller receives data transmitted by the online water quality monitor and then controls the opening and closing of each electric valve according to a program. The water inlet and outlet control system is powered by a municipal power grid, wherein the online water quality detector and the valve control system are both connected with 220V alternating current of the municipal power grid.

The submersible pump pumps sewage to be treated in the wastewater pool into the reactor for treatment, once the water quality monitor detects that the quality of the effluent reaches the standard, the valve control system opens the drain valve to drain, and simultaneously the valve control system opens the water inlet valve to introduce the sewage to be treated with the same drainage quantity to the wastewater pool and enter a new treatment process.

The reactor is cooperatively powered by a storage battery, solar energy and a municipal power grid, wherein the solar energy is collected by a solar panel and generates electric energy which is output in the form of voltage.

As shown in fig. 4, the reactor main body comprises an anode plate (MMO anode), a leak-proof rubber mat, a corrosion-resistant plastic frame, a leak-proof rubber mat, a cation exchange membrane, a leak-proof rubber mat, a corrosion-resistant plastic frame in which a porous carbon electrode loaded with a three-dimensional Fe-Mo-S catalyst is placed, a leak-proof rubber mat, and a cathode plate (graphite cathode) in this order, wherein the order is not in accordance with the requirements. The parts are tightly connected by screws, water flow firstly flows through the anode chamber, then is led out by a plastic pipe, then flows into the cathode chamber, and finally flows out of the cathode chamber, so that the primary treatment process of sewage is completed.

The front of the reactor main body is connected with a water pump, the rear of the reactor main body is connected with a water tank, the water pump pumps water and sends the water into the reactor main body, and sewage flows into the water tank after being treated by the reactor. The pressure reduction module is connected with the storage battery in front and connected with the anode and the cathode of the reactor main body and the water pump in back, and the electric energy after pressure reduction is transmitted to the reactor main body and the water pump for use.

The water flow sequence of the reactor is that water enters from a small hole at the upper end of the MMO anode, sequentially passes through the rubber mat and the corrosion-resistant plastic frame, is guided by the corrosion-resistant plastic frame and then forms anode outlet water at the lower end of the MMO anode through the rubber mat, the anode outlet water enters the reactor from a small hole at the upper end of the graphite cathode through the corrosion-resistant water delivery rubber hose, the water flow sequentially passes through the rubber mat and the Fe-carbon felt cathode and then is guided by the corrosion-resistant plastic frame, the water flow passes through the rubber mat, and forms cathode outlet water at a small hole below the graphite cathode, namely finally treated clean water.

The reactor takes a graphite electrode as a cathode and an MMO electrode as an anode, attaches a monatomic iron catalyst to Mo S, then is loaded on a three-dimensional carbon felt (namely a porous carbon electrode loaded by a three-dimensional Fe-Mo-S catalyst) in a cathode chamber, and treats high-concentration organic wastewater by adopting an electro-Fenton method. The negative plate, the positive plate, the leak-proof rubber mat, the corrosion-resistant plastic frame, the cation exchange membrane and the porous carbon electrode loaded by the three-dimensional Fe-Mo-S catalyst in the reactor are all stacked in parallel.

The reactor is a cuboid flow electrolytic cell with the height of 12cm, the length of 8cm, the width of 7cm and the weight of 0.95kg, the volume of the reactor is 10mL, and the minimum effective area of an electrode is 0.01m²。

The reactor clamps the side holes of the cathode plate and the anode plate through alligator clips on the leads so that the reactor is connected with the anode and the cathode of the power supply, the upper part of the anode plate is provided with a water inlet, and the lower part of the cathode plate is provided with a water outlet.

The MMO electrode is a mixed metal oxide anode, also called an insoluble anode, the anode body is composed of a continuous titanium substrate, and the mixed metal oxide is coated on the titanium substrate.

The mixed metal oxide anode, the leak-proof rubber mat and the graphite cathode in the reactor are all provided with an up-down inclined hole.

The porous carbon electrode loaded by the three-dimensional Fe-Mo-S catalyst is a porous carbon fiber felt, and iron is confined in a two-dimensional material MoS in a monoatomic form₂And the nano-sheet is attached to a three-dimensional carbon felt electrode in a nano-sheet form, and is called as an Fe-carbon felt cathode for short.

The leak-proof rubber mat contains three types: four holes, inclined hole alignment and no hole.

The plastic used by the corrosion-resistant plastic frame is polyvinylidene fluoride, polypropylene or other thermoplastic plastics, the middle of the corrosion-resistant plastic frame is provided with a flow guide hole for playing a flow guide role, and a three-dimensional Fe-Mo-S carbon felt electrode is arranged in the frame close to the graphite cathode.

The carbon felt of the cathode chamber is attached with a catalyst, so that the electro-Fenton reaction activity is enhanced, and high-concentration organic wastewater is efficiently treated.

The water inlet and outlet of the reactor is controlled by a water inlet and outlet control system, and the water inlet and outlet control system comprises a water quality online monitoring system and a valve control system.

The water quality on-line monitoring system is an aqueous solution on-line COD sensor and comprises a sensor and a probe, wherein the sensor consists of a control key, a display screen, a heat dissipation hole, a shell and a wiring terminal.

The valve control system is an electric valve for controlling the opening and closing of the water solution on-line COD sensor.

The three-dimensional carbon felt is a felt-like material prepared by carbonizing a high polymer at high temperature, is loose and porous, and has good chemical stability and electrical conductivity.

Further, the cathode chamber has three-dimensional Fe-Mo-S carbon felt which is positioned in the cathode chamber during the wastewater treatment process and has the following three characteristics: the three-dimensional structure of the carbon felt increases the contact area of the cathode and the wastewater, reduces the internal resistance and reduces the energy consumption of the electrode; MoS₂The existence of the Fe confinement region enables the Fe confinement region to exist in a two-dimensional layered structure in a single-atom scale, and further the energy level structure and the electronic structure of Fe are greatly changed, so that the single-atom iron catalyst shows activity, selectivity and stability different from those of the traditional iron-based catalyst in Fenton reaction; iron atom pair MoS₂The doping of which changes the MoS₂The original charge distribution activates MoS₂Redox activity of, MoS₂The catalyst is matched with the monatomic iron to synergistically catalyze the Fenton reaction, and hydroxyl radicals are efficiently generated to degrade organic pollutants in the wastewater.

Furthermore, in the process of treating wastewater in the anode chamber, the metal oxide electrode MMO positioned in the anode chamber can also generate hydroxyl radicals under the electrolysis action, so that the cathode effluent is purified again.

As shown in fig. 3, in the photoelectric complementary system, the solar panel is mounted on the sunlight tracking base, and the sunlight can be automatically ensured to be perpendicular to the solar panel according to the position of the sun, so as to obtain the maximum light intensity. The electrocatalysis water treatment reactor is cooperatively powered by a storage battery, solar energy and an external municipal power grid, and the power supply scheme can solve the problem of insufficient power supply of a solar panel in rainy days; in addition, the scheme ensures that the device still runs for a period of time when encountering a power failure accident, and avoids the risk of waste water overstocking after the accident; meanwhile, the power supply proportion of solar energy and a municipal power grid can be flexibly matched in practical engineering application, and a solar panel with a proper area is assembled according to practical conditions such as the available area of a factory, the local sunshine condition and the like, so that the reliability and the engineering applicability of the device are greatly improved.

The voltage reduction module is composed of a voltage reducer and is used for reducing the voltage generated by the solar panel to reach the actual required voltage of the reaction device.

As shown in fig. 3, the voltage reduction module is connected with the solar panel controller, the municipal power grid, the storage battery, the small water pump and the reactor body cathode and anode, can receive the non-constant voltage transmitted from the solar panel controller and the constant voltage transmitted from the municipal power grid or the storage battery, and outputs the stable voltage through voltage reduction and voltage stabilization to provide the stable voltage for the small water pump and the reactor body.

As shown in fig. 3, the small water pump has small volume, the shell is made of compact plastic, and the small water pump has the functions of air tightness and insulation; the small water pump is provided with a lead, is connected to a voltage output interface of the voltage stabilizing module, receives the stabilized voltage converted by the voltage reducing module, has three power levels for selection, and meets the requirement of gear shifting operation according to actual conditions under different experimental conditions.

As shown in fig. 3, the water inlet and outlet control system comprises an online water quality monitor, a valve control system and a submersible pump. The submersible pump pumps sewage to be treated in the wastewater pool into the reactor for treatment, once the water quality monitor detects that the quality of the effluent reaches the standard, the valve control system opens the drain valve to drain, and simultaneously the valve control system opens the water inlet valve to introduce the sewage to be treated with the same drainage quantity to the wastewater pool and enter a new treatment process.

Further, the water inlet and outlet control system has two working modes: firstly, sewage is treated by a reactor once and is discharged according to standards, and the system keeps continuous water inlet and drainage under the mode; secondly, the sewage can be discharged after reaching the standard after being treated by a plurality of reactors, and can be realized by two modes of multi-reactor series connection and single-reactor circulation. The mode II improves the upper limit of the device for treating the concentration of the organic wastewater; for the multi-reactor series treatment mode, the sewage treated by the device enters a new sewage pool, then flows through a new-stage reactor again for treatment, is connected with enough reactors in series until the effluent reaches the discharge standard, and the system continuously feeds water and discharges water under the mode; in the single-reactor circulation treatment mode, the sewage treated by the device flows into the same sewage tank again, and the system cannot receive new sewage in the mode, so that the sewage treatment system can be used only in some special cases.

The working principle of the photoelectric-driven three-dimensional electro-Fenton water treatment device provided by the invention (taking an outdoor environment test as an example) is as follows:

connect business turn over water control system, small-size water pump, voltage stabilizing module, solar panel and controller, open the water pump and put into high concentration organic waste water, the waste water is pumped to reactor main part positive pole, flows by reactor main part positive pole again, gets into reactor main part negative pole, flows by reactor main part negative pole again, accomplishes a purification process.

The working state of the photoelectric-driven three-dimensional electro-Fenton water treatment device provided by the invention under the condition that a single reactor is circulated for multiple times in a mode II is given in the embodiment:

the invention is used for carrying out a multiple circulation experiment based on a single reactor in the mode II, a device is started, and the simulation printing and dyeing wastewater passes through a valve K after being treated by the reactor₂And then flows back to the original sewage pool (as shown in figure 3), so that the concentration of the original wastewater is reduced, the load of the circular treatment of the device is reduced, and the occupied area is reduced.

Through a valve K₂And the effluent water which is purified flows back to the wastewater pool until the concentration of the simulated printing and dyeing wastewater in the pool is reduced to be below the standard, sampling and analyzing are carried out at regular time, absorbance analysis is carried out, and data of absorbance changing along with time are obtained to reflect the COD level in the water, so that the follow-up experimental study is facilitated.

Analysis shows that the COD removal rate of the simulated printing and dyeing wastewater in the original wastewater pool reaches 63.5% about 0.5h, and the COD removal rate of the simulated printing and dyeing wastewater reaches 83.8% after 2h of treatment, as shown in figure 5.

Example 5

The embodiment provides the working state of the photoelectric-driven three-dimensional electro-Fenton water treatment device under the condition that the multistage reactors in the first mode or the second mode are connected in series:

the invention is used for carrying out a multi-stage reactor series treatment experiment based on the mode I or the mode II, and simulating the condition that the printing and dyeing wastewater is treated by the reactorThrough business turn over water control system, business turn over water control system can detect aquatic organic pollutant content, can also control opening and close of gate simultaneously, if the water quality after the processing is up to standard, then through control flap K₁Opening the valve to discharge the treated water into a clean water pool for direct discharge, and simultaneously controlling the valve K₃Starting (as shown in figure 3), and supplementing the same amount of the simulated printing and dyeing wastewater to be treated; if the water quality of the treated water does not reach the standard, the valve K is controlled₂And opening the wastewater treatment tank, so that the treated water flows back to the original wastewater tank for purification again. During the period, whether the treated water quality reaches the standard can be detected through the water quality detection module.

Through a valve K₂And the effluent water which is subjected to the purification process flows back to the wastewater pool to be continuously treated, and is sampled and analyzed at regular time during the treatment, so that absorbance analysis is carried out, and data of absorbance changing along with time is obtained to reflect the COD level in the water, thereby facilitating the subsequent experimental study.

Analysis shows that the removal rate of COD in the wastewater can be stabilized at more than 98% as shown in figure 5.

Example 6

The embodiment provides the effect of the photoelectric-driven three-dimensional electro-Fenton water treatment device on removing COD (chemical oxygen demand) in simulated printing and dyeing wastewater under different plate voltages:

taking 0.02g/L orange II and 0.8mol/L sodium chloride solution as simulated wastewater, setting five groups of experiments under the conditions that the flow rate of a pump is 10L/h (the hydraulic retention time is 3.6s) and the room temperature, wherein the voltage is 1.0V, 1.5V, 1.8V, 2.0V and 2.2V respectively, and carrying out 4 parallel experiments under the voltage of each group. Firstly, introducing simulated wastewater under the condition of power failure until the water quality of water inlet and outlet ends is consistent, removing the adsorption effect of a carbon felt, then providing required stable voltage by using a voltage-stabilizing direct-current power supply, and collecting 0.02L of outlet water after the outlet water at the water outlet end is about 0.05L, thereby ensuring that all collected solutions are treated wastewater. After collection, the above experimental steps are repeated until the experiment is completed. And respectively collecting 0.02L water samples from the water inlet and the water outlet, measuring the COD value of each group of water samples, averaging, and inspecting the influence of the electrolytic voltage on the COD removal rate.

As shown in fig. 6, when the voltage is 2V or less, the COD removal rate greatly increases with the increase in voltage. When the electrolytic voltage was increased to 2V, the COD removal rate reached 95%. When the electrolytic voltage continues to increase, the removal rate does not change significantly although the current changes greatly. After comprehensive analysis, 2V is determined as the optimal electrolysis voltage of the device.

Example 7

The embodiment provides the effect of the photoelectric-driven three-dimensional electro-Fenton water treatment device on removing COD (chemical oxygen demand) in simulated printing and dyeing wastewater and actual industrial wastewater respectively under different plate voltages:

0.02g/L of orange II and 0.8mol/L of sodium chloride solution are taken as simulated wastewater, actual wastewater generated in the dye industry, the chemical industry and the pharmaceutical industry is respectively numbered as actual industrial wastewater 1, 2 and 3, the content of organic solvent in the actual industrial wastewater 1, 2 and 3 is respectively about 10%, 20% and 30%, and the wastewater belongs to high-concentration organic industrial wastewater. Under the conditions that the flow rate of a pump is 10L/h (the hydraulic retention time is 3.6s) and the room temperature, 4 x 4 groups of experiments are set, the voltage is respectively 1V, 2V, 4V and 8V, and 4 times of parallel experiments are carried out under the voltage of each group. Firstly, under the condition of power failure, introducing wastewater until the water quality of a water inlet end and a water outlet end is consistent, removing the adsorption effect of a carbon felt, then providing required stable voltage by using a voltage-stabilizing direct-current power supply, and collecting 0.02L of outlet water after the outlet water of the water outlet end is about 0.05L, so as to ensure that all collected solutions are treated wastewater. After collection, the above experimental steps are repeated until the experiment is completed. And respectively collecting 0.02L water samples from the water inlet and the water outlet, measuring the COD value of each group of water samples, averaging, and inspecting the influence of the electrolytic voltage on the COD removal rate.

As shown in fig. 7, the removal effect of the apparatus on the actual wastewater is lower than the treatment effect on the simulated dye wastewater, because the actual wastewater composition is more complicated; along with the continuous increase of the organic solvent ratio in the actual wastewater, the COD removal rate under the same voltage is continuously reduced; meanwhile, the COD removal rate of the wastewater is increased along with the increase of the voltage. When the voltage rises to 4V, no matter simulation waste water or actual waste water all have better removal effect, and the COD clearance of actual waste water begins to appear increasing slow phenomenon, and when the voltage rises to 8V, all actual industrial waste water can both reach more than 95% removal effect, and the COD clearance difference is less.

The photoelectric-driven three-dimensional electro-Fenton water treatment device provided by the invention is used for treating simulated printing and dyeing wastewater, the wastewater is purified mainly through hydroxyl radicals generated in a cathode and anode chamber of a reactor main body, electric energy required by the operation of the device is provided through a photoelectric complementary system, and the wastewater treatment quality and the continuous operation of the device are ensured through a water inlet and outlet control system. The device has the advantages of simple structure and convenient operation, and can realize the purification of the simulated printing and dyeing wastewater without generating secondary pollution.

Although the terms photovoltaic complementary system, solar panel, accumulator, controller, reactor body, pressure reduction module, water inlet and outlet control system, mini water pump, valve K1, valve K2, valve K3, simulated printing wastewater, actual industrial wastewater, etc. are used more herein, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to any additional limitations that may be imposed by the spirit of the present invention.

It is to be understood that the above examples are illustrative only for the purpose of clarity of description and are not limiting of the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.