Method for treating refractory organic matters in fly ash based on electro-catalysis-ozone coupling

Abstract

The invention discloses a method for treating refractory organics in fly ash based on electro-catalysis-ozone coupling, and relates to the technical field of fly ash treatment. According to the method, an electro-catalytic cathode electrode is an OCB / PCF electrode; the OCB / PCF electrode is an electrode formed by loading oxidized carbon black on a PAN-based carbon fiber felt electrode. Through the synergistic effect of electro-catalysis and ozone, the generation efficiency and reaction activity of free radicals are remarkably improved. The OCB / PCF electrode material has a high specific surface area and abundant active sites, can efficiently activate ozone molecules, generates intermediates such as H2O2 through an electrochemical reduction reaction, and further triggers a free radical chain reaction. The synergistic mechanism can realize deep oxygenolysis of refractory organic matters such as dioxin and polycyclic aromatic hydrocarbon, and the treatment effect is far better than that of a single ozone or electro-catalysis technology.

Description

Technical Field

[0001] The present invention relates to the technical field of fly ash treatment, in particular to a method for treating refractory organic matter in fly ash based on electrocatalysis-ozone coupling. Background Art

[0002] Incineration fly ash, a waste product generated during the incineration process, is primarily composed of inorganic salts (chlorides and sulfates), heavy metals (such as lead and cadmium), and refractory organic compounds (such as dioxins and polychlorinated biphenyls). Organic contaminants in fly ash easily combine with soluble salts, resulting in reduced product purity during waste salt recovery. Thermal decomposition of these organic contaminants can even generate secondary pollutants, hindering the harmlessness and resource utilization of fly ash. However, the removal of these organic contaminants presents two major challenges: first, their complex molecular structure and high chemical bond energy make them difficult to completely destroy using conventional oxidation technologies; second, the complex matrix of high salt content and multiple metal ions in fly ash easily reacts with oxidants, significantly reducing degradation efficiency. Therefore, developing efficient treatment technologies for refractory organic contaminants in fly ash is both an urgent environmental safety issue and a key prerequisite for the clean recovery of waste salt.

[0003] Currently, the main treatment methods for refractory organic matter in fly ash include: wet chemical oxidation, high-temperature melting vitrification, and physical adsorption. Wet chemical oxidation often uses a strong acid / strong base system for leaching treatment, but it has problems such as low reaction efficiency and easy secondary pollution. Although high-temperature melting technology can achieve thermal decomposition of organic matter, the energy consumption is as high as over 1400°C and it is easy to cause heavy metal volatilization. The adsorption method often uses materials such as activated carbon to enrich pollutants, but it cannot achieve complete mineralization of organic matter. The biodegradation method developed in recent years is limited by the tolerance of microorganisms to highly toxic environments. In actual application, the degradation cycle is as long as 30 days or more. The above methods generally have defects such as incomplete treatment, high operating costs, or secondary environmental risks.

[0004] Advanced oxidation technology (AOPs) can generate strong oxidative free radicals (such as OH, E 0=2.8V) and has become an effective means of degrading difficult-to-degrade organic matter. Traditional Fenton method, photocatalytic oxidation and other technologies face problems such as easy catalyst deactivation and low light energy utilization in fly ash treatment. Although ozone oxidation has strong oxidizing ability, it has poor selectivity for non-polar organic matter such as polycyclic aromatic hydrocarbons when used alone, and the ozone mass transfer efficiency restricts the reaction kinetics. Electrocatalysis-ozone coupling technology is a new advanced oxidation technology that combines electrocatalysis and ozone oxidation. It uses a carbon cathode to electroreduced O2 to generate H2O2 under power, which then undergoes an ozonation reaction with O3 to generate hydroxyl radicals with strong oxidizing properties, thereby non-selectively and deeply degrading organic pollutants. At the same time, micro-eddies can be formed on the surface of the electrocatalytic electrode to enhance gas-liquid-solid three-phase mass transfer, which is suitable for the deep mineralization of organic pollutants in fly ash slurry systems, providing a solution to the problems of low oxidation efficiency and high energy consumption of existing technologies.

[0005] The document "Wang Zhaojia, Qin Yu, Gu Jun, et al. Research progress in dioxin control technology of fly ash from municipal solid waste incineration [J]. Environmental Engineering, 2021, 39(10):116-123.DOI:10.13205 / j.hjgc.202110016." discloses that the participation of ozone in the catalytic degradation of organic pollutants can effectively improve the degradation efficiency of organic matter. Wang et al. studied the degradation of dioxins by O3-coupled copper-based and manganese-based modified vanadium catalysts, and found that the addition of ozone helps to improve the degradation of low-chlorinated dioxins. Chen et al. studied the reaction of ozone-assisted supported CuO catalytic oxidation of chlorobenzene and found that the addition of ozone can effectively reduce the activation energy of chlorobenzene decomposition and promote the reaction. Although the above documents record that the ozone-metal catalyst system can improve the degradation efficiency of organic matter, it does not disclose information about the ozone-electrocatalyst system.

[0006] Chinese invention patent CN116135796A discloses a ring-shaped carbon fiber electrode electrocatalytic-ozone coupling device and wastewater treatment method. The device includes a reaction vessel, a sealing cover is provided on the top of the reaction vessel, the bottom of the reaction vessel is connected to an ozone generator, and a water inlet pipe is provided in the reaction vessel. A carbon fiber anode plate and a carbon fiber C-PTFE cathode plate are provided on the outside of the water inlet pipe; the carbon fiber anode plate and the carbon fiber C-PTFE cathode plate are annular electrodes connected end to end. The ozone generator is turned on at the same time as the wastewater enters the reaction vessel from the water inlet; an electrolyte is added to the reaction vessel; a DC power supply is turned on, and current passes through the carbon fiber C-PTFE cathode plate and the carbon fiber anode plate, forming a loop with the wastewater in the reaction vessel, coupling ozone to treat the wastewater. Although the patent records the use of an electrocatalytic-ozone coupling device to treat wastewater, wastewater treatment is different from fly ash treatment, and the above treatment effect still needs to be improved. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for treating refractory organic matter in fly ash based on electrocatalysis-ozone coupling, in which H2O2 is generated in situ by electrocatalysis of oxygen, and reacts with introduced O3 to produce active oxygen free radicals, thereby achieving efficient mineralization of organic matter in fly ash and improving the removal rate of soluble organic carbon (DOC) in fly ash.

[0008] The experimental device of the present invention includes a dual-chamber electrochemical reactor, a direct current power supply, an oxygen generator, an ozone generator, an ozone detector, a gas flow meter, and a stirrer; the dual-chamber electrochemical reactor includes a cathode chamber, an anode chamber, and a proton exchange membrane, the cathode chamber and the anode chamber are separated by an ion exchange membrane, and a cathode electrode and an anode electrode are respectively placed in the cathode chamber and the anode chamber; the positive pole of the direct current power supply is connected to the anode electrode of the anode chamber, and the negative pole of the direct current power supply is connected to the cathode electrode of the cathode chamber; a stirrer is placed in the cathode chamber and the anode chamber; the ozone is produced by passing the oxygen generated by the oxygen generator through the ozone reactor, and the O2 / O3 mixed gas enters the cathode chamber through the gas flow meter.

[0009] In order to achieve the above-mentioned purpose of the invention, the technical solution of the present invention is as follows: The present invention provides a method for treating refractory organic matter in fly ash based on electrocatalysis-ozone coupling, wherein the electrocatalytic cathode electrode is an OCB / PCF electrode; the OCB / PCF electrode is an electrode formed by oxidized carbon black (OCB) loaded on a PAN-based carbon fiber felt (PCF) electrode.

[0010] Preferably, the electrocatalysis further comprises an anode, and the anode electrode is a platinum-titanium electrode.

[0011] Preferably, the method for preparing the OCB / PCF electrode comprises the steps of: S1 and PCF electrodes were cleaned in acetone, ethanol, and water in turn; S2, ultrasonically disperse carbon black in an anhydrous ethanol solution containing polytetrafluoroethylene emulsion, load the carbon black on the PCF electrode by filtration, and dry; S3. The dried electrode is calcined at high temperature to finally obtain an OCB / PCF cathode.

[0012] Further preferably, in step S1, the thickness of the PCF electrode is 1-5 mm, the porosity is 80%-95%, and the total pore area is 0.4-0.7 m 2 / g.

[0013] More preferably, in step S1, the thickness of the PCF electrode is 3 mm, the porosity is 85%, and the total pore area is 0.54 m 2 / g.

[0014] Further preferably, in step S1, the specific operation of the cleaning is: the PCF electrode is cleaned in each reagent for 0.5-1.5 hours, and the cleaning method is ultrasonic cleaning.

[0015] More preferably, in step S1, the cleaning time of the PCF electrode in each reagent is 1 hour.

[0016] Further preferably, in step S2, the concentration of the polytetrafluoroethylene emulsion in the ethanol solution of the polytetrafluoroethylene emulsion is 50-70 wt %.

[0017] More preferably, in step S2, the concentration of the polytetrafluoroethylene emulsion in the ethanol solution of the polytetrafluoroethylene emulsion is 60 wt %.

[0018] Further preferably, in step S2, the mass ratio of the polytetrafluoroethylene emulsion to carbon black is 0.1-0.6:1.

[0019] More preferably, in step S2, the mass ratio of the polytetrafluoroethylene emulsion to carbon black is 0.3:1.

[0020] Further preferably, in step S2, the specific operation of the filtration is: the PCF electrode is placed in a vacuum filtration device, the ultrasonically mixed solution is quickly poured into a filter cup, and filtered under vacuum pressure.

[0021] More preferably, in step S2, the drying temperature is 50-80°C, and the drying time is 10-30 minutes.

[0022] More preferably, in step S2, the drying temperature is 60° C. and the drying time is 25 minutes.

[0023] Further preferably, in step S3, the temperature of the high-temperature calcination is 200-500° C., the time of the high-temperature calcination is 20-60 min, and the heating rate is 5-10° C. / min.

[0024] More preferably, in step S3, the high-temperature calcination temperature is 400° C., the high-temperature calcination time is 30 min, and the heating rate is 5° C. / min.

[0025] Preferably, the method further comprises the steps of: (1) Incineration fly ash is pre-treated to obtain washing liquid; (2) Injecting a washing liquid and an O2 / O3 mixed gas into a dual-chamber electrochemical reactor to carry out an electrocatalytic-ozone coupling reaction; the electrocatalytic-ozone coupling reaction is carried out in the cathode chamber of the dual-chamber electrochemical reactor; and adding a supporting electrolyte Na2SO4 into the anode chamber of the dual-chamber electrochemical reactor.

[0026] Further preferably, in step (1), the washing pretreatment process is: mixing the incineration fly ash with water to obtain a suspension; the mass ratio of the incineration fly ash to water is 1:5-15.

[0027] More preferably, in step (1), the mass ratio of the incineration fly ash to water is 1:10.

[0028] Further preferably, in step (2), the concentration of the supporting electrolyte Na2SO4 is 0.05-0.2M.

[0029] More preferably, in step (2), the concentration of the supporting electrolyte Na2SO4 is 0.1M.

[0030] Further preferably, in step (2), the dual-chamber electrochemical reactor is connected to a DC power supply, the platinum-titanium electrode in the anode chamber is connected to the positive electrode of the DC power supply, and the OCB / PCF electrode in the cathode chamber is connected to the negative electrode of the DC power supply.

[0031] More preferably, in step (2), the areas of the platinum-titanium electrode and the OCB / PCF electrode are the same.

[0032] Further preferably, in step (2), the current density applied to the anode chamber and the cathode chamber is 5-50 mA / cm 2 .

[0033] More preferably, in step (2), the current density applied to the anode chamber and the cathode chamber is 20-40 mA / cm 2 .

[0034] More preferably, in step (2), the current density applied to the anode chamber and the cathode chamber is 20 mA / cm 2 .

[0035] Further preferably, in step (2), the concentration of O3 is 20-100 mg / L, and the flow rate of the O2 / O3 mixed gas is 30-200 mL / min.

[0036] More preferably, in step (2), the concentration of O3 is 50 mg / L, and the flow rate of the O2 / O3 mixed gas is 100 mL / min.

[0037] The beneficial effects of the present invention are: (1) The electrocatalytic-ozone coupled method for treating refractory organic matter in fly ash provided by the present invention can operate at low temperature and normal pressure, significantly reducing energy consumption and costs. Conventional high-temperature melting technology requires operation above 1200°C, while the present invention can achieve efficient degradation at room temperature and pressure, significantly reducing energy consumption. Carbon-based cathode materials are inexpensive and widely available, and do not require precious metal catalysts (such as Pt and IrO2), significantly reducing equipment investment and operating costs.

[0038] (2) The method of the present invention has high efficiency in degradation and mineralization: through the synergistic effect of electrocatalysis and ozone, it significantly increases the free radicals (such as ·OH, ·O3 - ) generation efficiency and reaction activity; OCB / PCF electrode materials have high specific surface area and abundant active sites, which can effectively activate ozone molecules (O3→·O3 - ), and through electrochemical reduction reactions, generate intermediates such as H2O2, which further trigger free radical chain reactions. This synergistic mechanism can achieve deep oxidative decomposition of difficult-to-degrade organic compounds such as dioxins and polycyclic aromatic hydrocarbons, far exceeding the treatment efficiency of single ozone or electrocatalytic technologies.

[0039] (3) Inhibit the generation of chlorinated by-products and have outstanding environmental friendliness: The present invention adopts a double-chamber reactor, and the chloride ions (Cl - ) is concentrated in the anode chamber and preferentially converted into ClO under the electrochemical oxidation of the anode - Or Cl2, while the cathode compartment blocks Cl through the ion exchange membrane - Migration of Cl - Migrate to the cathode chamber to participate in the side reaction, greatly reducing the generation of chlorinated by-products. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic structural diagram of the reaction device of Example 1 of the present invention, wherein 1 is an oxygen generator; 2 is an ozone generator; 3 is an ozone detector; 4 is a DC power supply; 5 is a dual-chamber electrochemical reactor; 6 is an anode electrode; 7 is an anode chamber; 8 is a cathode chamber; 9 is a cathode electrode; 10 is an ion exchange membrane; 11 is a stirrer; and 12 is a gas flow meter. DETAILED DESCRIPTION

[0041] The following non-limiting examples are provided to enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way. The following is merely an illustrative description of the scope of the present invention, and those skilled in the art may make various changes and modifications to the present invention based on the disclosed content, which should also fall within the scope of the present invention.

[0042] The present invention will be further described below by way of specific examples. The various chemical reagents used in the examples of the present invention were obtained through conventional commercial channels unless otherwise specified. Unless otherwise specified, the contents described below are all by weight. Unless otherwise specified, it is understood that the experiments were conducted at room temperature.

[0043] The platinum-titanium electrode was purchased from Suzhou Shuertai Industrial Technology Co., Ltd., and the thickness of the platinum layer was 5 μm.

[0044] Polyacrylonitrile-based (PAN-based) carbon fiber felt electrodes were purchased from Jingzhou Haote New Materials with the product number CFP-03J.

[0045] Polytetrafluoroethylene emulsion was purchased from Shanghai MacLean Biochemical Technology Co., Ltd. with the product number P816262.

[0046] Dissolved organic carbon (DOC) concentration determination method: DOC is determined using the combustion oxidation-non-dispersive infrared absorption method. 10 mL of fly ash washing liquid is filtered through a 0.45 μm aqueous membrane and then measured using a TOC analyzer (TOC-L).

[0047] The experimental device of an embodiment of the present invention includes a dual-chamber electrochemical reactor, a DC power supply, an oxygen generator, an ozone generator, an ozone detector, a gas flow meter, and a stirrer; the dual-chamber electrochemical reactor includes a cathode chamber, an anode chamber and a proton exchange membrane, the cathode chamber and the anode chamber are separated by an ion exchange membrane, and a cathode electrode and an anode electrode are placed in the cathode chamber and the anode chamber, respectively; the positive pole of the DC power supply is connected to the anode electrode of the anode chamber, and the negative pole of the DC power supply is connected to the cathode electrode of the cathode chamber; a stirrer is placed in the cathode chamber and the anode chamber; the ozone is produced by the oxygen generated by the oxygen generator through the ozone reactor, and the O2 / O3 mixed gas enters the cathode chamber through the gas flow meter.

[0048] Example 1 Electrocatalytic-ozone coupled reaction device such as Figure 1 As shown: ozone is generated by an oxygen concentrator 1 through an ozone generator 2, the gas ozone concentration is monitored by an ozone detector 3, the gas flow rate is controlled by a gas flow meter 12, the positive and negative electrodes of a DC power supply 4 are respectively connected to the anode electrode 6 and cathode electrode 9 of a dual-chamber electrochemical reactor 5, and a stirrer 11 is used for stirring to increase the reaction mass transfer; the anode electrode 6 is placed in the anode chamber, the cathode electrode 9 is placed in the cathode chamber, and the anode chamber 6 and the cathode chamber 8 are separated by a proton exchange membrane 10; the anode electrode 6 is a platinum-titanium electrode.

[0049] In this embodiment, the fly ash obtained from the Hangzhou Zhongtai Jiufeng Waste Incineration Plant is pretreated by mixing the obtained raw incineration fly ash with deionized water at a solid-liquid mass ratio of 1:10, and stirring with a magnetic stirrer for 30 minutes to obtain an initial washing liquid. The DOC concentration in the initial washing liquid is measured to be 548.62 mg / L.

[0050] The cathode electrode is an OCB / PCF electrode, and its preparation method is as follows: S1: PCF electrode (3 mm, porosity 85%, total pore area 0.54 m 2 / g) were placed in acetone, ethanol, and deionized water in sequence, and ultrasonically cleaned in each reagent for 1 hour each to obtain the treated PCF electrode for later use; S2: 50.24 mg of carbon black was ultrasonically dispersed in an anhydrous ethanol solution containing 25.12 mg of 60 wt% polytetrafluoroethylene emulsion (the mass ratio of polytetrafluoroethylene emulsion and carbon black was 0.3:1). The volume of ethanol was 50 mL. The carbon black was loaded on the PCF electrode by filtration and dried at 60 °C for 25 min. Then, the temperature was raised to 400 °C in a muffle furnace at a heating rate of 5 °C / min and calcined at a high temperature for 30 min to obtain an OCB / PCF cathode.

[0051] Experimental parameters: 150 mL of the reaction solution (initial washing solution) was placed in the cathode chamber 8 of the dual-chamber electrochemical reactor 5, and the current density was 20 mA / cm 2 The areas of cathode and anode are 9 cm 2 , the supporting electrolyte concentration in the anode chamber was 0.1 M Na2SO4, the ozone concentration was 50 mg / L, and the air inlet flow rate was 100 mL / min.

[0052] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 45.84 mg / L, and the removal rate was about 91.64%.

[0053] Example 2 In this embodiment, the experimental apparatus and the initial washing solution are the same as those in Example 1.

[0054] The cathode electrode is an OCB / PCF electrode, and its preparation method is as follows: S1: PCF electrode (3 mm, porosity 85%, total pore area 0.54 m 2 / g) were placed in acetone, ethanol, and deionized water in sequence, and ultrasonically cleaned in each reagent for 1 hour each to obtain the treated PCF electrode for later use; S2: 50.24 mg of carbon black was ultrasonically dispersed in an anhydrous ethanol solution containing 25.12 mg of 60 wt% polytetrafluoroethylene emulsion (the mass ratio of polytetrafluoroethylene emulsion and carbon black was 0.3:1). The volume of ethanol was 50 mL. The carbon black was loaded on the PCF electrode by filtration, dried at 60 °C for 25 min, and then calcined at 300 °C in a muffle furnace at a heating rate of 5 °C / min for 30 min to obtain an OCB / PCF cathode.

[0055] Experimental parameters: 150 mL of the reaction solution (initial washing solution) was placed in the cathode chamber 8 of the dual-chamber electrochemical reactor 5, and the current density was 20 mA / cm 2 The areas of cathode and anode are 9 cm 2 , the supporting electrolyte concentration in the anode chamber is 0.1MNa2SO4, the ozone concentration is 50mg / L, and the air inlet flow rate is 100mL / min.

[0056] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 69.24 mg / L, and the removal rate was about 87.38%.

[0057] Example 3 In this embodiment, the experimental apparatus and the initial washing solution are the same as those in Example 1.

[0058] The cathode electrode is an OCB / PCF electrode, and its preparation method is as follows: S1: PCF electrode (3 mm, porosity 85%, total pore area 0.54 m 2 / g) were placed in acetone, ethanol, and deionized water in sequence, and ultrasonically cleaned in each reagent for 1 hour each to obtain the treated PCF electrode for later use; S3: 50.24 mg of carbon black was ultrasonically dispersed in an ethanol solution containing 25.12 mg of 60 wt% polytetrafluoroethylene emulsion (the mass ratio of polytetrafluoroethylene emulsion to carbon black was 0.3:1). The volume of ethanol was 50 mL. The carbon black was loaded on the PCF electrode by filtration and dried at 60 °C for 25 min. Then, the temperature was raised to 200 °C in a muffle furnace at a heating rate of 5 °C / min and calcined at a high temperature for 30 min to obtain an OCB / PCF cathode.

[0059] Experimental parameters: 150 mL of the reaction solution (initial washing solution) was placed in the cathode chamber 8 of the dual-chamber electrochemical reactor 5, and the current density was 20 mA / cm 2 The areas of cathode and anode are 9 cm 2 , the supporting electrolyte concentration in the anode chamber is 0.1MNa2SO4, the ozone concentration is 50mg / L, and the air inlet flow rate is 100mL / min.

[0060] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 106.27 mg / L, and the removal rate was about 80.63%.

[0061] Example 4 In this embodiment, the experimental apparatus and the initial washing solution are the same as those in Example 1.

[0062] The cathode electrode is an OCB / PCF electrode, and its preparation method is as follows: S1: PCF electrode (3 mm, porosity 85%, total pore area 0.54 m 2 / g) were placed in acetone, ethanol, and deionized water in sequence, and ultrasonically cleaned in each reagent for 1 hour each to obtain the treated PCF electrode for later use; S2: 50.24 mg of carbon black was ultrasonically dispersed in an anhydrous ethanol solution containing 25.12 mg of 60 wt% polytetrafluoroethylene emulsion (the mass ratio of polytetrafluoroethylene emulsion and carbon black was 0.3:1). The volume of ethanol was 50 mL. The carbon black was loaded on the PCF electrode by filtration and dried at 60 °C for 25 min. Then, the temperature was raised to 400 °C in a muffle furnace at a heating rate of 5 °C / min and calcined at a high temperature for 30 min to obtain an OCB / PCF cathode.

[0063] Experimental parameters: 150 mL of the reaction solution (initial washing solution) was placed in the cathode chamber 8 of the dual-chamber electrochemical reactor 5, and the current density was 30 mA / cm 2 The areas of cathode and anode are 9 cm 2 , the supporting electrolyte concentration in the anode chamber is 0.1MNa2SO4, the ozone concentration is 60mg / L, and the air inlet flow rate is 100mL / min.

[0064] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 38.81 mg / L, and the removal rate was about 92.93%.

[0065] Example 5 In this embodiment, the experimental apparatus and the initial washing solution are the same as those in Example 1.

[0066] The cathode electrode is an OCB / PCF electrode, and its preparation method is as follows: S1: PCF electrode (3 mm, porosity 85%, total pore area 0.54 m 2 / g) were placed in acetone, ethanol, and deionized water in sequence, and ultrasonically cleaned in each reagent for 1 hour each to obtain the treated PCF electrode for later use; S2: 50.24 mg of carbon black was ultrasonically dispersed in an anhydrous ethanol solution containing 25.12 mg of 60 wt% polytetrafluoroethylene emulsion (the mass ratio of polytetrafluoroethylene emulsion and carbon black was 0.3:1). The volume of ethanol was 50 mL. The carbon black was loaded on the PCF electrode by filtration and dried at 60 °C for 25 min. Then, the temperature was raised to 400 °C in a muffle furnace at a heating rate of 5 °C / min and calcined at a high temperature for 30 min to obtain an OCB / PCF cathode.

[0067] Experimental parameters: 150 mL of the reaction solution (initial washing solution) was placed in the cathode chamber 8 of the dual-chamber electrochemical reactor 5, and the current density was 30 mA / cm 2The areas of cathode and anode are 9 cm 2 , the supporting electrolyte concentration in the anode chamber is 0.1MNa2SO4, the ozone concentration is 60mg / L, and the air inlet flow rate is 100mL / min.

[0068] After 90 min of treatment under the above conditions, the DOC concentration in the washing liquid was 30.42 mg / L, and the removal rate was about 94.46%.

[0069] Example 6 In this embodiment, the experimental apparatus is the same as that in embodiment 1.

[0070] The fly ash obtained from the Ningbo Fenghua Waste Incineration Plant was pretreated as follows: the original incineration fly ash was mixed with deionized water at a solid-liquid mass ratio of 1:10, and stirred with a magnetic stirrer for 30 minutes to obtain an initial washing liquid. The DOC concentration in the initial washing liquid was measured to be 652.96 mg / L.

[0071] The cathode electrode is an OCB / PCF electrode, and its preparation method is as follows: S1: PCF electrode (3 mm, porosity 85%, total pore area 0.54 m 2 / g) were placed in acetone, ethanol, and deionized water in sequence, and ultrasonically cleaned in each reagent for 1 hour each to obtain the treated PCF electrode for later use; S2: 50.24 mg of carbon black was ultrasonically dispersed in an ethanol solution containing 25.12 mg of 60 wt% polytetrafluoroethylene emulsion (the mass ratio of polytetrafluoroethylene emulsion to carbon black was 0.3). The volume of ethanol was 50 mL. The carbon black was loaded on the PCF electrode by filtration and dried at 60 °C for 25 min. Then, the temperature was raised to 400 °C in a muffle furnace at a heating rate of 5 °C / min and calcined at a high temperature for 30 min to obtain an OCB / PCF cathode.

[0072] Experimental parameters: 150 mL of the reaction solution (initial washing solution) was placed in the cathode chamber 8 of the dual-chamber electrochemical reactor 5, and the current density was 20 mA / cm 2 The areas of cathode and anode are 9 cm 2 , the supporting electrolyte concentration in the anode chamber is 0.1MNa2SO4, the ozone concentration is 50mg / L, and the air inlet flow rate is 100mL / min.

[0073] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 86.48 mg / L, and the removal rate was about 86.76%.

[0074] Example 7 In this embodiment, the experimental apparatus is the same as that in embodiment 1.

[0075] The pretreatment method of the fly ash obtained from the Huzhou Changxing Waste Incineration Plant is as follows: the obtained original incineration fly ash is mixed with deionized water at a solid-liquid mass ratio of 1:10, and stirred with a magnetic stirrer for 30 minutes to obtain an initial washing liquid. The DOC concentration in the initial washing liquid is measured to be 431.84 mg / L.

[0076] The cathode electrode is an OCB / PCF electrode, and its preparation method is as follows: S1: PCF electrode (3 mm, porosity 85%, total pore area 0.54 m 2 / g) were placed in acetone, ethanol, and deionized water in sequence, and ultrasonically cleaned in each reagent for 1 hour each to obtain the treated PCF electrode for later use; S2: 50.24 mg of carbon black was ultrasonically dispersed in an ethanol solution containing 25.12 mg of 60 wt% polytetrafluoroethylene emulsion (the mass ratio of polytetrafluoroethylene emulsion to carbon black was 0.3). The volume of ethanol was 50 mL. The carbon black was loaded on the PCF electrode by filtration and dried at 60 °C for 25 min. Then, the temperature was raised to 400 °C in a muffle furnace at a heating rate of 5 °C / min and calcined at a high temperature for 30 min to obtain an OCB / PCF cathode.

[0077] Experimental parameters: 150 mL of the reaction solution (initial washing solution) was placed in the cathode chamber 8 of the dual-chamber electrochemical reactor 5, and the current density was 20 mA / cm 2 The areas of cathode and anode are 9 cm 2 , the supporting electrolyte concentration in the anode chamber is 0.1MNa2SO4, the ozone concentration is 50mg / L, and the air inlet flow rate is 100mL / min.

[0078] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 34.11 mg / L, and the removal rate was about 92.10%.

[0079] Example 8 In this embodiment, the experimental apparatus is the same as that in embodiment 1.

[0080] The fly ash obtained from the Jiaxing Nanhu Waste Incineration Plant was pretreated as follows: the original incineration fly ash was mixed with deionized water at a solid-liquid mass ratio of 1:10, and stirred with a magnetic stirrer for 30 minutes to obtain an initial washing liquid. The DOC concentration in the initial washing liquid was measured to be 1016.83 mg / L.

[0081] The cathode electrode is an OCB / PCF electrode, and its preparation method is as follows: S1: PCF electrode (3 mm, porosity 85%, total pore area 0.54 m 2 / g) were placed in acetone, ethanol, and deionized water in sequence, and ultrasonically cleaned in each reagent for 1 hour each to obtain the treated PCF electrode for later use; S2: 50.24 mg of carbon black was ultrasonically dispersed in an ethanol solution containing 25.12 mg of 60 wt% polytetrafluoroethylene emulsion (the mass ratio of polytetrafluoroethylene emulsion to carbon black was 0.3). The volume of ethanol was 50 mL. The carbon black was loaded on the PCF electrode by filtration and dried at 60 °C for 25 min. Then, the temperature was raised to 400 °C in a muffle furnace at a heating rate of 5 °C / min and calcined at a high temperature for 30 min to obtain an OCB / PCF cathode.

[0082] Experimental parameters: 150 mL of the reaction solution (initial washing solution) was placed in the cathode chamber 8 of the dual-chamber electrochemical reactor 5, and the current density was 40 mA / cm 2 The areas of cathode and anode are 9 cm 2 , the supporting electrolyte concentration in the anode chamber is 0.1MNa2SO4, the ozone concentration is 80mg / L, and the air inlet flow rate is 150mL / min.

[0083] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 173.62 mg / L, and the removal rate was about 82.93%.

[0084] Comparative Example 1 Different from Example 1, this comparative example treats the refractory organic matter in the incineration fly ash by simple electrocatalysis without introducing ozone.

[0085] The fly ash source, pretreatment and electrode material preparation method are the same as in Example 1.

[0086] The experimental parameters are: the reaction solution (initial washing solution) is 150 mL, the current density is 20 mA / cm 2 The areas of cathode and anode are 9 cm 2 , the supporting electrolyte concentration in the anode chamber was 0.1 M Na2SO4, and the oxygen inlet flow rate was 100 mL / min.

[0087] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 418.54 mg / L, and the removal rate was about 23.71%.

[0088] Comparative Example 2 Different from Example 1, this comparative example treats the refractory organic matter in the incineration fly ash simply by using ozone.

[0089] The fly ash source and pretreatment method are the same as in Example 1.

[0090] The experimental parameters are as follows: the reaction solution (initial washing solution) is 150 mL, the ozone concentration is controlled to be 50 mg / L, and the air inlet flow rate is 100 mL / min.

[0091] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 283.82 mg / L, and the removal rate was about 48.27%.

[0092] Comparative Example 3 Different from Example 1, the cathode of this comparative example is a carbon fiber C-PTFE cathode plate, and the anode is a carbon fiber anode plate.

[0093] In this embodiment, the experimental apparatus is the same as that in embodiment 1.

[0094] The fly ash source and pretreatment method are the same as in Example 1.

[0095] The cathode is a carbon fiber C-PTFE cathode plate, and the anode is a carbon fiber anode plate.

[0096] Experimental parameters: 150 mL of the reaction solution (initial washing solution) was placed in the cathode chamber 8 of the dual-chamber electrochemical reactor 5, and the current density was 20 mA / cm 2 The areas of cathode and anode are 9 cm 2 , the supporting electrolyte concentration in the anode chamber is 0.1MNa2SO4, the ozone concentration is 50mg / L, and the air inlet flow rate is 100mL / min.

[0097] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 207.54 g / L, and the removal rate was about 62.17%.

[0098] Comparative Example 4 Different from Example 1, the cathode of this comparative example is a carbon cloth electrode, and the anode is the same as that of Example 1.

[0099] In this embodiment, the experimental apparatus is the same as that in embodiment 1.

[0100] The fly ash source and pretreatment method are the same as in Example 1.

[0101] Experimental parameters: 150 mL of the reaction solution (initial washing solution) was placed in the cathode chamber 8 of the dual-chamber electrochemical reactor 5, and the current density was 20 mA / cm 2 The areas of cathode and anode are 9 cm 2 , the supporting electrolyte concentration in the anode chamber is 0.1MNa2SO4, the ozone concentration is 50mg / L, and the air inlet flow rate is 100mL / min.

[0102] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 243.76 mg / L, and the removal rate was about 55.57%.

[0103] Comparative Example 5 Different from Example 1, the cathode of this comparative example is an untreated pure PCF electrode, and the anode is the same as that of Example 1.

[0104] In this embodiment, the experimental apparatus is the same as that in embodiment 1.

[0105] The fly ash source and pretreatment method are the same as in Example 1.

[0106] Experimental parameters: 150 mL of the reaction solution (initial washing solution) was placed in the cathode chamber 8 of the dual-chamber electrochemical reactor 5, and the current density was 20 mA / cm 2 The areas of cathode and anode are 9 cm 2 , the supporting electrolyte concentration in the anode chamber is 0.1MNa2SO4, the ozone concentration is 50mg / L, and the air inlet flow rate is 100mL / min.

[0107] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 269.29 mg / L, and the removal rate was about 50.92%.

[0108] Comparative Example 6 The difference from Example 1 is that this comparative example uses homogeneous catalytic ozone oxidation (Fe 2+ / O3) method to treat the difficult-to-degrade organic matter in incineration fly ash.

[0109] In this embodiment, the fly ash source and pretreatment method are the same as those in Example 1.

[0110] Experimental parameters: reaction solution (initial washing solution) is 150 mL, ferrous sulfate concentration is 1.0 mmol / L, ozone concentration is 50 mg / L, and air flow rate is 100 mL / min.

[0111] After 60 min of treatment under the above conditions, the DOC concentration in the washing liquid was 327.58 mg / L, and the removal rate was about 40.29%.

[0112] 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 in the scope of protection of the present invention.

Claims

1. A method for treating refractory organic matter in fly ash based on electrocatalysis-ozone coupling, characterized in that: The electrocatalytic cathode electrode is an OCB / PCF electrode; the OCB / PCF electrode is an electrode formed by oxidized carbon black loaded on a PAN-based carbon fiber felt electrode.

2. The method according to claim 1, characterized in that The electrocatalysis also includes an anode electrode, which is a platinum-titanium electrode.

3. The method according to claim 1, characterized in that The preparation method of the OCB / PCF electrode comprises the following steps: S1 and PCF electrodes were cleaned in acetone, ethanol, and water in turn; S2, ultrasonically dispersing carbon black in an ethanol solution containing polytetrafluoroethylene emulsion, loading the carbon black on the PCF electrode by filtration, and drying; S3. The dried electrode is calcined at high temperature to finally obtain an OCB / PCF cathode.

4. The method according to claim 3, characterized in that In step S2, the concentration of the polytetrafluoroethylene emulsion in the ethanol solution of the polytetrafluoroethylene emulsion is 50-70 wt %.

5. The method according to claim 3, characterized in that In step S2, the mass ratio of the polytetrafluoroethylene emulsion to carbon black is 0.1-0.6:

1.

6. The method according to claim 3, characterized in that In step S3, the high-temperature calcination temperature is 200-500° C., the high-temperature calcination time is 20-60 min, and the heating rate is 5-10° C. / min.

7. The method according to claim 1, characterized in that The method further comprises the steps of: (1) Incineration fly ash is pre-treated to obtain washing liquid; (2) Injecting a washing liquid and an O2 / O3 mixed gas into a dual-chamber electrochemical reactor to carry out an electrocatalytic-ozone coupling reaction; the electrocatalytic-ozone coupling reaction is carried out in the cathode chamber of the dual-chamber electrochemical reactor; and adding a supporting electrolyte Na2SO4 into the anode chamber of the dual-chamber electrochemical reactor.

8. The method according to claim 7, characterized in that In step (1), the washing pretreatment process is: mixing the incineration fly ash with water to obtain a suspension; the mass ratio of the incineration fly ash to water is 1:5-15.

9. The method according to claim 7, characterized in that In step (2), the current density applied to the anode chamber and the cathode chamber is 5-50 mA / cm 2 .

10. The method according to claim 7, characterized in that In step (2), the concentration of O3 is 20-100 mg / L, and the flow rate of the O2 / O3 mixed gas is 30-200 mL / min.

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