A method for advanced oxidation treatment of wastewater using a BDD electrode

Abstract

This invention discloses a method for advanced oxidation treatment of wastewater using a BDD electrode, belonging to the field of wastewater treatment. The BDD electrode prepared by this invention has a high oxygen evolution potential, and can generate a large amount of strong oxidizing substances such as hydroxyl radicals, peroxides, and ozone during the reaction. The boron-doped BDD electrode supported by nickel and lanthanum bimetals exposes more active sites, which is beneficial for the ammonia oxidation reaction. It efficiently degrades toxic substances in water, especially recalcitrant organic pollutants, into CO2, H2O, etc., without secondary pollution. The BDD electrode prepared by this invention has good electrochemical stability and chemical inertness, its surface is not easily contaminated, and surface contaminants can be removed by high-pressure incineration without affecting the electrode's properties, achieving a self-cleaning effect. Therefore, the BDD electrode can be used for a long time without replacement.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and in particular to a method for advanced oxidation treatment of wastewater using a BDD electrode. Background Technology

[0002] High-concentration, recalcitrant industrial wastewater causes severe environmental pollution due to its high concentration, large pollution volume, and difficulty in treatment, making it a focus of social concern and research. Current traditional methods for treating industrial wastewater are either too costly or fail to meet emission standards. Electrochemical degradation technology, however, shows great potential due to its high catalytic degradation activity, ease of automation and integration with other processes, and lack of secondary pollution. The core component of electrochemical degradation technology is the electrode material, with boron-doped diamond thin film (BDD) electrodes becoming a recent focus of application research due to their superior performance.

[0003] Chinese Patent CN109179814A discloses a method for treating wastewater using a combined advanced oxidation process. First, wastewater is passed into an ultraviolet catalytic reactor while an oxidant is added to decompose organic matter in the wastewater that can be decomposed by ultraviolet catalytic oxidation. Then, the wastewater is passed into a porous carbon-filled electrolytic reactor to break down organic molecules that cannot be decomposed by ultraviolet catalytic oxidation. Finally, the wastewater is passed into an ultraviolet catalytic reactor while an oxidant is added to oxidize small-molecule organic matter in the wastewater into carbon dioxide and water. This invention has advantages such as high degradation efficiency, simple structure, safe and reliable operation, minimal solid or hazardous waste generation during operation, long service life, easy achievement of emission standards, and ease of automation.

[0004] Chinese Patent CN115536207A relates to a method and apparatus for advanced wastewater treatment, belonging to the field of recalcitrant wastewater treatment technology. The advanced wastewater treatment method involves preheating the wastewater in a heat exchanger, adding an oxidant, and then introducing it into an ultraviolet (UV) light generator. Under the catalytic action of UV light, the oxidant generates highly oxidizing free radicals, which then enter a pre-oxidizer for reaction, with the reaction temperature controlled. Most of the effluent from the pre-oxidizer is recycled back to the UV light generator, while a portion enters a buffer, where a biochemical regulator is added. The effluent from the buffer enters a biochemical reactor for biological treatment, and is then cooled by a heat exchanger before being discharged. This invention features low dosage and high utilization rate of the advanced oxidant, high biochemical treatment efficiency, high organic matter degradation efficiency, a short process, and stable operation. The apparatus used is simple in structure, rationally designed, and occupies a small area.

[0005] Chinese Patent CN107082473A discloses an advanced oxidation device for wastewater treatment, including a housing with an oxidation chamber inside. Electrode plate supports are fixedly mounted on the left and right inner walls of the oxidation chamber, and electrode plates are movably engaged on the electrode plate supports. The invention also discloses an advanced oxidation method for wastewater treatment, comprising the following steps: Step 1: Installing electrode plates sequentially on the electrode plate supports of the oxidation chamber; Step 2: Opening the valve on the fluid inlet pipe while simultaneously closing the valves on the fluid outlet pipe and the sewage outlet pipe. This invention fixes the electrode plates using the electrode plate supports and facilitates the installation and removal of the electrode plates using a slot structure, thereby adjusting the electrode plate spacing according to different types of wastewater. Wastewater sequentially passes through the electrode plates to one end of the fluid outlet pipe, where an oxidation-reduction reaction occurs on the electrode plates, separating impurities from the wastewater. Simultaneously, the sewage outlet pipe is periodically opened to clean the sediment separated in the oxidation chamber.

[0006] The wastewater treatment methods described above, including patents and existing technologies, each have their advantages and disadvantages. For example, biological treatment methods are insufficient for treating high concentrations of organic matter, highly toxic or difficult-to-biodegrade organic compounds. If physical or chemical methods are used for removal, it may require processes such as adsorption, extraction, precipitation, addition of oxidants, and electrolysis. These processes are complex, and the introduction of new substances can easily cause secondary pollution. Incomplete treatment may even generate more toxic intermediate products, and the costs are high.

[0007] Existing BDD electrodes mostly use Si, Ta, Nb, and W as substrates. However, these substrates suffer from drawbacks such as poor conductivity, low mechanical strength, or high cost. Si is currently the most widely used substrate material because its coefficient of thermal expansion is similar to that of diamond, and it has a small lattice mismatch, good bonding force, and Si / BDD electrodes also exhibit good electrochemical properties. However, silicon is a semiconductor with poor conductivity and low mechanical strength, limiting its application in electrochemical wastewater treatment. Therefore, researchers have attempted to deposit diamond films on metal substrates. Currently, Nb, Ta, W, and Ti have been identified as suitable substrate metals. These metals can deposit diamond and possess electrochemical inertness; however, the first three metals are expensive, limiting their large-scale industrial use. Summary of the Invention

[0008] To address the problems mentioned above in the background art, the present invention provides a method for advanced oxidation treatment of wastewater using a BDD electrode, the operation steps of which are as follows:

[0009] Wastewater from the wastewater storage tank enters the electrolytic cell via a water pump and flow control system. The electrolytic cell is connected to a DC power supply. After electrolysis, the wastewater is cooled by a cooler, and non-condensable gases are discharged. The cooled wastewater is discharged after passing a test.

[0010] As one of the preferred embodiments, the electrolytic cell is composed of three BDD electrodes. A double-sided BDD film in the middle divides the electrolytic cell into two parallel sections. One side of the BDD film electrode serves as the anode, and the other side as the cathode. The thickness of the BDD film is 1-3 μm, and the working area of ​​each BDD film is 60-80 cm². 2 The electrodes are separated by plastic partitions, with a distance of 1-2 mm between them; the current density is 30-60 mA / cm². 2 .

[0011] As one of the preferred options, the BDD electrode is the anode and stainless steel is the cathode; the electrolyte is a mixture of Dalton hydraulic oil, waste engine oil emulsifier, and tridecanol polyoxyethylene ether in a volume ratio of 7-10:1:1, and then mixed with water in a volume ratio of 7-10:1; sodium chloride is added to the electrolyte as an electrolyte in an amount of 2-6 g / L.

[0012] As one of the preferred solutions, the BDD electrode is first immersed in a diluted sulfuric acid solution at 50-80 mA / cm² before electrolytic treatment of wastewater. 2 Electrolyze for 20-40 minutes to polarize it.

[0013] As one of the preferred methods, after electrolysis, the BDD electrode is heated in an oil bath to 100-150°C for 2-5 hours in a mixed solution of concentrated H2SO4 and concentrated HNO3 at a ratio of 1-3:1.

[0014] As one of the preferred options, the method for preparing the BDD electrode is as follows:

[0015] S1: Place the titanium plate on the substrate support, and then adjust the height so that it is on the same horizontal line as the waveguide;

[0016] S2: Introduce hydrogen gas, start the vacuum pump, turn on the microwave power supply, and turn on the reflection device. The carbon source and boron source are brought into the reaction chamber by H2, and deposition begins. After deposition, a BDD electrode is obtained.

[0017] As one of the preferred options, the carbon source is methane.

[0018] As one of the preferred options, the boron source is reacted with nickel nitrate, lanthanum nitrate and p-mercapto-terephthalic acid to obtain a p-mercapto-terephthalic acid-nickel / lanthanum complex; then it undergoes a thiol addition reaction with an ethylene boric anhydride pyridine complex, and is then compounded with trimethyl borate to obtain the final product.

[0019] Specifically, one method for preparing a boron source is as follows:

[0020] B1: Select 15-30 parts by weight of nickel nitrate, 0.2-0.7 parts by weight of lanthanum nitrate and 30-60 parts by weight of p-mercapto-terephthalic acid, add them to reaction vessel 1, then add 300-450 parts by weight of methanol, stir at 30-40℃ for 100-150 min, remove methanol by distillation, and obtain p-mercapto-terephthalic acid-nickel / lanthanum complex;

[0021] B2: Weigh 3-8 parts of ethylene boric anhydride pyridine complex and add them to the reaction vessel, then add 5-10 parts of p-mercapto-terephthalic acid-nickel / lanthanum complex, 2-5 parts of triethylamine, 30-50 parts of trimethyl borate, and 100-150 parts of DMF. Stir at 55-65℃ for 100-150 min to obtain the boron source.

[0022] As one of the preferred options, the carbon source flow rate is 1-3 sccm and the hydrogen flow rate is 100-300 sccm.

[0023] As one of the preferred options, the pressure is 5-7 kPa, the power is 380 W, and the deposition time is 7-10 h.

[0024] The technical effects of this invention are as follows:

[0025] 1. The BDD electrode prepared by this invention has a high oxygen evolution potential and can generate a large amount of strong oxidizing substances such as hydroxyl radicals, peroxides, and ozone in the reaction. The boron-doped BDD electrode supported by nickel and lanthanum bimetals can expose more active sites, which is conducive to the ammonia oxidation reaction. It can efficiently degrade toxic substances in water, especially recalcitrant organic pollutants, into CO2, H2O, etc., without secondary pollution.

[0026] 2. The BDD electrode prepared by this invention has good adsorption inertness, which allows a large amount of strong oxidizing substances generated on the electrode surface to be rapidly transferred into the solution to participate in the degradation reaction of organic matter, resulting in high current efficiency.

[0027] 3. The BDD electrode prepared by this invention has good electrochemical stability and chemical inertness, and its surface is not easily contaminated. Moreover, the contaminants attached to the surface can be removed by high-pressure incineration without affecting the properties of the electrode itself, thus achieving a self-cleaning effect. Therefore, the BDD electrode can be used for a long time without replacement. Detailed Implementation

[0028] To make the present invention easier to understand, the present invention will be described in detail below with reference to the embodiments. These embodiments are for illustrative purposes only and are not limited to the application scope of the present invention. Specific experimental methods not mentioned in the following embodiments are usually carried out according to conventional experimental methods.

[0029] The specific implementation scheme of this invention is measured according to the following method:

[0030] 1. Chemical oxygen demand was determined according to the national standard GB11914-89;

[0031] 2. Biochemical oxygen demand was measured using a Scientificasrl instrument from Germany;

[0032] 3. Conductivity was measured using a DDSJ-308A conductivity meter. Example 1

[0033] A method for advanced oxidation treatment of wastewater using a BDD electrode, comprising the following steps:

[0034] Wastewater from the wastewater storage tank enters the electrolytic cell via a water pump and flow control system. The electrolytic cell is connected to a DC power supply. After electrolysis, the wastewater is cooled by a cooler, and non-condensable gases are discharged. The cooled wastewater is discharged after passing a test.

[0035] The electrolytic cell is composed of three BDD electrodes. A double-sided BDD film in the middle divides the electrolytic cell into two parallel cells. One side of the BDD film electrode serves as the anode, and the other side serves as the cathode. The thickness of the BDD film is 1 μm, and the working area of ​​each BDD film is 60 cm². 2 The electrodes are separated by plastic partitions, with a distance of 1 mm between them; the current density is 30 mA / cm². 2 .

[0036] The BDD electrode is the anode, and stainless steel is the cathode. The electrolyte is a mixture of Dalton hydraulic oil, waste engine oil emulsifier, and tridecanol polyoxyethylene ether in a volume ratio of 7:1:1, and then mixed with water in a volume ratio of 7:1. Sodium chloride is added to the electrolyte as an electrolyte at a concentration of 2 g / L.

[0037] Before electrolyzing wastewater, the BDD electrode is first immersed in a diluted sulfuric acid solution at 50 mA / cm. 2 Electrolyze for 20 minutes to polarize it.

[0038] After electrolysis, the BDD electrode is heated to 100°C in an oil bath in a 1:1 mixed solution of concentrated H2SO4 and concentrated HNO3 for 2 hours for treatment.

[0039] The method for preparing the BDD electrode is as follows:

[0040] S1: Place the titanium plate on the substrate support, and then adjust the height so that it is on the same horizontal line as the waveguide;

[0041] S2: Introduce hydrogen gas, start the vacuum pump, turn on the microwave power supply, and turn on the reflection device. The carbon source and boron source are brought into the reaction chamber by H2, and deposition begins. After deposition, a BDD electrode is obtained.

[0042] The carbon source is methane.

[0043] The method for preparing the boron source is as follows:

[0044] B1: Select 15g of nickel nitrate, 0.2g of lanthanum nitrate and 30g of p-mercapto-terephthalic acid, add them to reaction vessel 1, then add 300g of methanol, stir at 30℃ for 100min, and remove methanol by distillation to obtain p-mercapto-terephthalic acid-nickel / lanthanum complex.

[0045] B2: Weigh 3g of ethylene boric anhydride pyridine complex and add it to the reaction vessel. Then add 5g of p-mercapto-terephthalic acid-nickel / lanthanum complex, 2g of triethylamine, 30g of trimethyl borate, and 100g of DMF. Stir at 55℃ for 100min to obtain the boron source.

[0046] The carbon source flow rate is 1 sccm, and the hydrogen flow rate is 100 sccm.

[0047] The pressure was 5 kPa, the power was 380 W, and the deposition time was 7 h. Example 2

[0048] A method for advanced oxidation treatment of wastewater using a BDD electrode, comprising the following steps:

[0049] Wastewater from the wastewater storage tank enters the electrolytic cell via a water pump and flow control system. The electrolytic cell is connected to a DC power supply. After electrolysis, the wastewater is cooled by a cooler, and non-condensable gases are discharged. The cooled wastewater is discharged after passing a test.

[0050] The electrolytic cell is composed of three BDD electrodes. A double-sided BDD film in the middle divides the electrolytic cell into two parallel cells. One side of the BDD film electrode serves as the anode and the other as the cathode. The thickness of the BDD film is 2 μm, and the working area of ​​each BDD film is 65 cm². 2 The electrodes are separated by plastic partitions, with a distance of 1 mm between them; the current density is 40 mA / cm². 2 .

[0051] The BDD electrode is the anode, and stainless steel is the cathode. The electrolyte is a mixture of Dalton hydraulic oil, waste engine oil emulsifier, and tridecanol polyoxyethylene ether in a volume ratio of 8:1:1, and then mixed with water in a volume ratio of 8:1. Sodium chloride is added to the electrolyte as an electrolyte at a concentration of 3 g / L.

[0052] Before electrolyzing wastewater, the BDD electrode is first immersed in a diluted sulfuric acid solution at 60 mA / cm. 2 Electrolyze for 25 minutes to polarize it.

[0053] After electrolysis, the BDD electrode is heated to 110°C in an oil bath in a mixed solution of concentrated H2SO4 and concentrated HNO3 in a ratio of 2:1 for 3 hours for treatment.

[0054] The method for preparing the BDD electrode is as follows:

[0055] S1: Place the titanium plate on the substrate support, and then adjust the height so that it is on the same horizontal line as the waveguide;

[0056] S2: Introduce hydrogen gas, start the vacuum pump, turn on the microwave power supply, and turn on the reflection device. The carbon source and boron source are brought into the reaction chamber by H2, and deposition begins. After deposition, a BDD electrode is obtained.

[0057] The carbon source is methane.

[0058] The method for preparing the boron source is as follows:

[0059] B1: Select 20g of nickel nitrate, 0.4g of lanthanum nitrate and 40g of p-mercapto-terephthalic acid, add them to reaction vessel 1, then add 350g of methanol, stir at 35℃ for 110min, remove methanol by distillation, and obtain p-mercapto-terephthalic acid-nickel / lanthanum complex.

[0060] B2: Weigh 4g of ethylene boric anhydride pyridine complex and add it to the reaction vessel. Then add 6g of p-mercapto-terephthalic acid-nickel / lanthanum complex, 3g of triethylamine, 35g of trimethyl borate, and 110g of DMF. Stir at 60℃ for 110min to obtain the boron source.

[0061] The carbon source flow rate is 2 sccm, and the hydrogen flow rate is 150 sccm.

[0062] The pressure was 6 kPa, the power was 380 W, and the deposition time was 8 h. Example 3

[0063] A method for advanced oxidation treatment of wastewater using a BDD electrode, comprising the following steps:

[0064] Wastewater from the wastewater storage tank enters the electrolytic cell via a water pump and flow control system. The electrolytic cell is connected to a DC power supply. After electrolysis, the wastewater is cooled by a cooler, and non-condensable gases are discharged. The cooled wastewater is discharged after passing a test.

[0065] The electrolytic cell is composed of three BDD electrodes. A double-sided BDD film in the middle divides the electrolytic cell into two parallel cells. One side of the BDD film electrode serves as the anode and the other as the cathode. The thickness of the BDD film is 2 μm, and the working area of ​​each BDD film is 75 cm². 2 The electrodes are separated by plastic partitions, with a distance of 2 mm between them; the current density is 50 mA / cm². 2 .

[0066] The BDD electrode is the anode, and stainless steel is the cathode. The electrolyte is a mixture of Dalton hydraulic oil, waste engine oil emulsifier, and tridecanol polyoxyethylene ether in a volume ratio of 9:1:1, and then mixed with water in a volume ratio of 9:1. Sodium chloride is added to the electrolyte as an electrolyte at a concentration of 5 g / L.

[0067] Before electrolyzing wastewater, the BDD electrode is first immersed in a diluted sulfuric acid solution at 70 mA / cm. 2 Electrolyze for 35 minutes to polarize it.

[0068] After electrolysis, the BDD electrode is heated to 140°C in an oil bath in a mixed solution of concentrated H2SO4 and concentrated HNO3 in a ratio of 2:1 for 4 hours for treatment.

[0069] The method for preparing the BDD electrode is as follows:

[0070] S1: Place the titanium plate on the substrate support, and then adjust the height so that it is on the same horizontal line as the waveguide;

[0071] S2: Introduce hydrogen gas, start the vacuum pump, turn on the microwave power supply, and turn on the reflection device. The carbon source and boron source are brought into the reaction chamber by H2, and deposition begins. After deposition, a BDD electrode is obtained.

[0072] The carbon source is methane.

[0073] The method for preparing the boron source is as follows:

[0074] B1: Select 25g of nickel nitrate, 0.6g of lanthanum nitrate and 50g of p-mercapto-terephthalic acid, add them to reaction vessel 1, then add 400g of methanol, stir at 35℃ for 140min, remove methanol by distillation, and obtain p-mercapto-terephthalic acid-nickel / lanthanum complex.

[0075] B2: Weigh 7g of ethylene boric anhydride pyridine complex and add it to the reaction vessel. Then add 9g of p-mercapto-terephthalic acid-nickel / lanthanum complex, 4g of triethylamine, 45g of trimethyl borate, and 140g of DMF. Stir at 60℃ for 140min to obtain the boron source.

[0076] The carbon source flow rate is 2 sccm, and the hydrogen flow rate is 250 sccm.

[0077] The pressure was 6 kPa, the power was 380 W, and the deposition time was 9 h. Example 4

[0078] A method for advanced oxidation treatment of wastewater using a BDD electrode, comprising the following steps:

[0079] Wastewater from the wastewater storage tank enters the electrolytic cell via a water pump and flow control system. The electrolytic cell is connected to a DC power supply. After electrolysis, the wastewater is cooled by a cooler, and non-condensable gases are discharged. The cooled wastewater is discharged after passing a test.

[0080] The electrolytic cell is composed of three BDD electrodes. A double-sided BDD film in the middle divides the electrolytic cell into two parallel cells. One side of the BDD film electrode serves as the anode, and the other side serves as the cathode. The thickness of the BDD film is 3 μm, and the working area of ​​each BDD film is 80 cm². 2 The electrodes are separated by plastic partitions, with a distance of 2 mm between them; the current density is 60 mA / cm². 2 .

[0081] The BDD electrode is the anode, and stainless steel is the cathode. The electrolyte is a mixture of Dalton hydraulic oil, waste engine oil emulsifier, and tridecanol polyoxyethylene ether in a volume ratio of 10:1:1, and then mixed with water in a volume ratio of 10:1. Sodium chloride is added to the electrolyte as an electrolyte at a concentration of 6 g / L.

[0082] Before electrolyzing wastewater, the BDD electrode is first immersed in a diluted sulfuric acid solution at 80 mA / cm. 2 Electrolyze for 40 minutes to polarize it.

[0083] After electrolysis, the BDD electrode is heated to 150°C in an oil bath in a mixed solution of concentrated H2SO4 and concentrated HNO3 in a ratio of 3:1 for 5 hours for treatment.

[0084] The method for preparing the BDD electrode is as follows:

[0085] S1: Place the titanium plate on the substrate support, and then adjust the height so that it is on the same horizontal line as the waveguide;

[0086] S2: Introduce hydrogen gas, start the vacuum pump, turn on the microwave power supply, and turn on the reflection device. The carbon source and boron source are brought into the reaction chamber by H2, and deposition begins. After deposition, a BDD electrode is obtained.

[0087] The carbon source is methane.

[0088] The method for preparing the boron source is as follows:

[0089] B1: Select 30g of nickel nitrate, 0.7g of lanthanum nitrate and 60g of p-mercapto-terephthalic acid, add them to reaction vessel 1, then add 450g of methanol, stir at 40℃ for 150min, and remove methanol by distillation to obtain p-mercapto-terephthalic acid-nickel / lanthanum complex.

[0090] B2: Weigh 8g of ethylene boric anhydride pyridine complex and add it to the reaction vessel, then add 10g of p-mercapto-terephthalic acid-nickel / lanthanum complex, 5g of triethylamine, 50g of trimethyl borate, and 150g of DMF. Stir at 65℃ for 150min to obtain the boron source.

[0091] The carbon source flow rate is 3 sccm, and the hydrogen flow rate is 300 sccm.

[0092] The pressure was 7 kPa, the power was 380 W, and the deposition time was 10 h.

[0093] Comparative Example 1

[0094] A method for advanced oxidation treatment of wastewater using a BDD electrode, comprising the following steps:

[0095] Wastewater from the wastewater storage tank enters the electrolytic cell via a water pump and flow control system. The electrolytic cell is connected to a DC power supply. After electrolysis, the wastewater is cooled by a cooler, and non-condensable gases are discharged. The cooled wastewater is discharged after passing a test.

[0096] The electrolytic cell is composed of three BDD electrodes. A double-sided BDD film in the middle divides the electrolytic cell into two parallel cells. One side of the BDD film electrode serves as the anode, and the other side serves as the cathode. The thickness of the BDD film is 1 μm, and the working area of ​​each BDD film is 60 cm². 2 The electrodes are separated by plastic partitions, with a distance of 1 mm between them; the current density is 30 mA / cm². 2 .

[0097] The BDD electrode is the anode, and stainless steel is the cathode. The electrolyte is a mixture of Dalton hydraulic oil, waste engine oil emulsifier, and tridecanol polyoxyethylene ether in a volume ratio of 7:1:1, and then mixed with water in a volume ratio of 7:1. Sodium chloride is added to the electrolyte as an electrolyte at a concentration of 2 g / L.

[0098] Before electrolyzing wastewater, the BDD electrode is first immersed in a diluted sulfuric acid solution at 50 mA / cm. 2 Electrolyze for 20 minutes to polarize it.

[0099] After electrolysis, the BDD electrode is heated to 100°C in an oil bath in a 1:1 mixed solution of concentrated H2SO4 and concentrated HNO3 for 2 hours for treatment.

[0100] The method for preparing the BDD electrode is as follows:

[0101] S1: Place the titanium plate on the substrate support, and then adjust the height so that it is on the same horizontal line as the waveguide;

[0102] S2: Introduce hydrogen gas, start the vacuum pump, turn on the microwave power supply, and turn on the reflection device. The carbon source and boron source are brought into the reaction chamber by H2, and deposition begins. After deposition, a BDD electrode is obtained.

[0103] The carbon source is methane.

[0104] The method for preparing the boron source is as follows:

[0105] B1: Select 0.2g of lanthanum nitrate and 30g of p-mercapto-terephthalic acid, add them to reaction vessel 1, then add 300g of methanol, stir at 30℃ for 100min, remove methanol by distillation, and obtain p-mercapto-terephthalic acid-nickel / lanthanum complex.

[0106] B2: Weigh 3g of ethylene boric anhydride pyridine complex and add it to the reaction vessel. Then add 5g of p-mercapto-terephthalic acid-nickel / lanthanum complex, 2g of triethylamine, 30g of trimethyl borate, and 100g of DMF. Stir at 55℃ for 100min to obtain the boron source.

[0107] The carbon source flow rate is 1 sccm, and the hydrogen flow rate is 100 sccm.

[0108] The pressure was 5 kPa, the power was 380 W, and the deposition time was 7 h.

[0109] Comparative Example 2

[0110] A method for advanced oxidation treatment of wastewater using a BDD electrode, comprising the following steps:

[0111] Wastewater from the wastewater storage tank enters the electrolytic cell via a water pump and flow control system. The electrolytic cell is connected to a DC power supply. After electrolysis, the wastewater is cooled by a cooler, and non-condensable gases are discharged. The cooled wastewater is discharged after passing a test.

[0112] The electrolytic cell is composed of three BDD electrodes. A double-sided BDD film in the middle divides the electrolytic cell into two parallel cells. One side of the BDD film electrode serves as the anode, and the other side serves as the cathode. The thickness of the BDD film is 1 μm, and the working area of ​​each BDD film is 60 cm². 2 The electrodes are separated by plastic partitions, with a distance of 1 mm between them; the current density is 30 mA / cm². 2 .

[0113] The BDD electrode is the anode, and stainless steel is the cathode. The electrolyte is a mixture of Dalton hydraulic oil, waste engine oil emulsifier, and tridecanol polyoxyethylene ether in a volume ratio of 7:1:1, and then mixed with water in a volume ratio of 7:1. Sodium chloride is added to the electrolyte as an electrolyte at a concentration of 2 g / L.

[0114] Before electrolyzing wastewater, the BDD electrode is first immersed in a diluted sulfuric acid solution at 50 mA / cm. 2 Electrolyze for 20 minutes to polarize it.

[0115] After electrolysis, the BDD electrode is heated to 100°C in an oil bath in a 1:1 mixed solution of concentrated H2SO4 and concentrated HNO3 for 2 hours for treatment.

[0116] The method for preparing the BDD electrode is as follows:

[0117] S1: Place the titanium plate on the substrate support, and then adjust the height so that it is on the same horizontal line as the waveguide;

[0118] S2: Introduce hydrogen gas, start the vacuum pump, turn on the microwave power supply, and turn on the reflection device. The carbon source and boron source are brought into the reaction chamber by H2, and deposition begins. After deposition, a BDD electrode is obtained.

[0119] The carbon source is methane.

[0120] The method for preparing the boron source is as follows:

[0121] B1: Select 15g of nickel nitrate and 30g of p-mercapto-terephthalic acid, add them to reaction vessel 1, then add 300g of methanol, stir at 30℃ for 100min, remove methanol by distillation, and obtain p-mercapto-terephthalic acid-nickel / lanthanum complex.

[0122] B2: Weigh 3g of ethylene boric anhydride pyridine complex and add it to the reaction vessel. Then add 5g of p-mercapto-terephthalic acid-nickel / lanthanum complex, 2g of triethylamine, 30g of trimethyl borate, and 100g of DMF. Stir at 55℃ for 100min to obtain the boron source.

[0123] The carbon source flow rate is 1 sccm, and the hydrogen flow rate is 100 sccm.

[0124] The pressure was 5 kPa, the power was 380 W, and the deposition time was 7 h.

[0125] Comparative Example 3

[0126] A method for advanced oxidation treatment of wastewater using a BDD electrode, comprising the following steps:

[0127] Wastewater from the wastewater storage tank enters the electrolytic cell via a water pump and flow control system. The electrolytic cell is connected to a DC power supply. After electrolysis, the wastewater is cooled by a cooler, and non-condensable gases are discharged. The cooled wastewater is discharged after passing a test.

[0128] The electrolytic cell is composed of three BDD electrodes. A double-sided BDD film in the middle divides the electrolytic cell into two parallel cells. One side of the BDD film electrode serves as the anode, and the other side serves as the cathode. The thickness of the BDD film is 1 μm, and the working area of ​​each BDD film is 60 cm². 2 The electrodes are separated by plastic partitions, with a distance of 1 mm between them; the current density is 30 mA / cm². 2 .

[0129] The BDD electrode is the anode, and stainless steel is the cathode. The electrolyte is a mixture of Dalton hydraulic oil, waste engine oil emulsifier, and tridecanol polyoxyethylene ether in a volume ratio of 7:1:1, and then mixed with water in a volume ratio of 7:1. Sodium chloride is added to the electrolyte as an electrolyte at a concentration of 2 g / L.

[0130] Before electrolyzing wastewater, the BDD electrode is first immersed in a diluted sulfuric acid solution at 50 mA / cm. 2 Electrolyze for 20 minutes to polarize it.

[0131] After electrolysis, the BDD electrode is heated to 100°C in an oil bath in a 1:1 mixed solution of concentrated H2SO4 and concentrated HNO3 for 2 hours for treatment.

[0132] The method for preparing the BDD electrode is as follows:

[0133] S1: Place the titanium plate on the substrate support, and then adjust the height so that it is on the same horizontal line as the waveguide;

[0134] S2: Introduce hydrogen gas, start the vacuum pump, turn on the microwave power supply, and turn on the reflection device. The carbon source and boron source are brought into the reaction chamber by H2, and deposition begins. After deposition, a BDD electrode is obtained.

[0135] The carbon source is methane.

[0136] The method for preparing the boron source is as follows:

[0137] B1: Select 15g of nickel nitrate, 0.2g of lanthanum nitrate and 30g of p-mercapto-terephthalic acid, add them to reaction vessel 1, then add 300g of methanol, stir at 30℃ for 100min, and remove methanol by distillation to obtain p-mercapto-terephthalic acid-nickel / lanthanum complex.

[0138] B2: Weigh 5g of p-mercapto-terephthalic acid-nickel / lanthanum complex, 2g of triethylamine, 30g of trimethyl borate, and 100g of DMF, and stir at 55℃ for 100min to obtain the boron source.

[0139] The carbon source flow rate is 1 sccm, and the hydrogen flow rate is 100 sccm.

[0140] The pressure was 5 kPa, the power was 380 W, and the deposition time was 7 h.

[0141] Table of test results for examples and comparative examples

[0142] Based on the data analysis of the above embodiments and comparative examples, the BDD electrode prepared by the present invention has the ability to efficiently degrade toxic substances in water, especially recalcitrant organic pollutants, into CO2, H2O, etc., without secondary pollution; the BDD electrode prepared by the present invention has high current efficiency.

[0143] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for advanced oxidation treatment of wastewater using a BDD electrode, comprising the following steps: Wastewater from the wastewater storage tank enters the electrolytic cell via a water pump and flow control system. The electrolytic cell is connected to a DC power supply. The wastewater after electrolysis is cooled by a cooler, and non-condensable gases are discharged. The cooled wastewater is discharged after passing the test. The BDD electrode is the anode, and stainless steel is the cathode; The method for preparing the BDD electrode is as follows: S1: Place the titanium plate on the substrate support, and then adjust the height so that it is on the same horizontal line as the waveguide; S2: Introduce hydrogen gas, start the vacuum pump, turn on the microwave power supply, and turn on the reflection device. H2 carries the carbon source and boron source into the reaction chamber to begin deposition. After deposition, a BDD electrode is obtained. The method for preparing the boron source is as follows: B1: Select 15-30 parts by weight of nickel nitrate, 0.2-0.7 parts by weight of lanthanum nitrate and 30-60 parts by weight of p-mercapto-terephthalic acid, add them to reaction vessel 1, then add 300-450 parts by weight of methanol, stir at 30-40℃ for 100-150 min, remove methanol by distillation, and obtain p-mercapto-terephthalic acid-nickel / lanthanum complex; B2: Weigh 3-8 parts of ethylene boric anhydride pyridine complex and add them to the reaction vessel, then add 5-10 parts of p-mercapto-terephthalic acid-nickel / lanthanum complex, 2-5 parts of triethylamine, 30-50 parts of trimethyl borate, and 100-150 parts of DMF. Stir at 55-65℃ for 100-150 min to obtain the boron source.

2. The method for advanced oxidation treatment of wastewater using a BDD electrode according to claim 1, characterized in that: The thickness of the BDD film is 1-3 μm, and the working area of ​​each BDD film is 60-80 cm2; the electrodes are separated by plastic partitions, and the distance between the electrodes is 1-2 mm; the current density is 30-60 mA / cm2.

3. The method for advanced oxidation treatment of wastewater using a BDD electrode according to claim 1, characterized in that: The electrolyte is a mixture of Dalton hydraulic oil, waste engine oil emulsifier, and tridecanol polyoxyethylene ether in a volume ratio of 7-10:1:1, and then mixed with water in a volume ratio of 7-10:

1. Sodium chloride is added to the electrolyte as an electrolyte at a concentration of 2-6 g / L.

4. The method for advanced oxidation treatment of wastewater using a BDD electrode according to claim 1, characterized in that: Before electrolyzing wastewater, the BDD electrode is first immersed in a diluted sulfuric acid solution at a current of 50-80 mA / cm. 2 Electrolyze for 20-40 minutes to polarize it.

5. The method for advanced oxidation treatment of wastewater using a BDD electrode according to claim 1, characterized in that: After electrolysis, the BDD electrode is heated in an oil bath to 100-150°C for 2-5 hours in a mixed solution of concentrated H2SO4 and concentrated HNO3 at a ratio of 1-3:

1.

6. The method for advanced oxidation treatment of wastewater using a BDD electrode according to claim 1, characterized in that: The carbon source is methane.

7. The method for advanced oxidation treatment of wastewater using a BDD electrode according to claim 6, characterized in that: The carbon source has a flow rate of 1-3 sccm, and the hydrogen flow rate has a flow rate of 100-300 sccm.

8. The method for advanced oxidation treatment of wastewater using a BDD electrode according to claim 1, characterized in that: The pressure of S2 is 5-7 kPa, the power is 380 W, and the deposition time is 7-10 h.

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