Electro-catalytic membrane reactor coupled ozone device for treating organic wastewater and implementation method of electro-catalytic membrane reactor coupled ozone device

Abstract

The invention aims to disclose an electro-catalytic membrane reactor coupled ozone device for treating organic wastewater and an implementation method thereof. The device comprises an electrolytic bath, a porous conductive carbon membrane assembly, an ozone generator, an aeration system, an ozone tail gas destructor, a water pump and a direct-current power supply, compared with the prior art, wastewater containing ozone and pollutants passes through a porous channel structure in the porous conductive carbon membrane component under the action of negative pressure provided by a water pump, and ozone is subjected to an electrocatalytic reaction under the action of an electric field to generate active substances such as hydroxyl radicals with strong oxidizing property; organic pollutants in water are oxidized and degraded into small molecules or are detoxified or mineralized into carbon dioxide and water, so that efficient removal of organic matters is realized, an electro-catalytic reaction of ozone is limited in holes of the porous conductive carbon membrane assembly, the mass transfer rate of ozone in a solution to the surface of an electrode is increased, and the electrochemical performance of the electrode is improved. And therefore, the pollutant removal effect and the ozone utilization rate are improved, the membrane-making wastewater can be effectively treated, cleanness and no secondary pollution are realized, and the aim of the invention is fulfilled.

Description

Technical Field

[0001] The invention relates to a wastewater treatment technology, in particular to an electrocatalytic membrane reactor coupled ozone device for treating organic wastewater and a realization method thereof. Background Art

[0002] High-concentration organic wastewater poses a serious threat to the environment. These wastewaters usually contain high concentrations of organic solvents and organic additives, which are bioinhibitory and highly chemically stable and are difficult to effectively remove through traditional biological treatment or physicochemical methods.

[0003] Ozone (O3) is a strong oxidant used to degrade difficult-to-degrade organic matter in water and has been widely used in wastewater treatment. However, ozone treatment alone is often inefficient. Combining electrocatalytic technology with ozone oxidation technology can effectively improve the utilization efficiency and treatment efficiency of ozone.

[0004] Electrocatalytic technology applies an electric field to the electrode to promote ozone to produce active substances such as enhanced hydroxyl free radicals, thereby achieving degradation and removal of organic matter, thereby improving oxidation efficiency. Although electrocatalytic technology has shown certain potential in wastewater treatment, the electrode plates of existing ozone electrocatalytic devices are often metal flat electrodes, which prevents ozone from quickly contacting the electrode plates, resulting in low pollutant removal efficiency, low ozone utilization rate and high cost, limiting its application in membrane wastewater treatment.

[0005] Therefore, there is a particular need for an electrocatalytic membrane reactor coupled with an ozone device for treating organic wastewater and a method for implementing the same to solve the above-mentioned existing problems. Summary of the invention

[0006] The purpose of the present invention is to provide an electrocatalytic membrane reactor coupled ozone device for treating organic wastewater and its implementation method, which aims to improve the mass transfer rate of ozone in the solution to the electrode surface, improve the pollutant removal effect and ozone utilization rate, and effectively treat membrane wastewater, cleanly and without secondary pollution.

[0007] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0008] In a first aspect, the present invention provides an electrocatalytic membrane reactor coupled with an ozone device for treating organic wastewater, comprising an electrolytic cell, a porous conductive carbon membrane assembly, an ozone generator, an aeration system, an ozone tail gas destroyer, a water pump and a DC power supply; the electrolytic cell is provided with a wastewater inlet, a wastewater outlet, an exhaust port and an air inlet; the electrolytic cell is provided with a plurality of porous conductive carbon membrane assemblies and an aeration system, the aeration system is arranged at the bottom of the electrolytic cell, the aeration system is connected to the ozone generator, and the exhaust port of the electrolytic cell is connected to the ozone tail gas destroyer; the cathode of the porous conductive carbon membrane assembly is connected to the negative electrode of the DC power supply through an external circuit connection line, the anode of the porous conductive carbon membrane assembly is connected to the positive electrode of the DC power supply through an external circuit connection line, the permeate outlet of the porous conductive carbon membrane assembly is connected to the water inlet end of the water pump, and the water outlet end of the water pump is connected to the wastewater inlet of the electrolytic cell.

[0009] In one embodiment of the present invention, the cathode of the porous conductive carbon membrane assembly is a plurality of porous conductive carbon membranes with an average pore size of 100-500nm, the anode of the porous conductive carbon membrane assembly is a graphite plate, and the distance between the cathode of the porous conductive carbon membrane assembly and the anode of the porous conductive carbon membrane assembly is 1-3cm.

[0010] Furthermore, the porous conductive carbon membrane is made of activated carbon material and is encapsulated in an acrylic seal. The acrylic seal is provided with an external circuit connection line and a permeate outlet. The permeate outlet is connected to the water inlet of a water pump, and the water outlet of the water pump is connected to the wastewater inlet of the electrolytic cell.

[0011] In one embodiment of the present invention, the cathode of the porous conductive carbon membrane assembly and the anode of the porous conductive carbon membrane assembly are fixed on the plastic bracket by plastic screws.

[0012] In one embodiment of the present invention, the aeration system includes but is not limited to an aeration plate aeration system and an ejector aeration system.

[0013] In one embodiment of the present invention, the external circuit connecting wire is made of TA2 titanium material.

[0014] In a second aspect, the present invention provides a method for treating organic wastewater by coupling an electrocatalytic membrane reactor with an ozone device, comprising the following steps:

[0015] a. Transporting membrane wastewater into the electrolytic cell through the wastewater inlet;

[0016] b. Start the DC power supply and apply positive and negative voltages to the anode and cathode of the porous conductive carbon membrane assembly in the electrolytic cell respectively;

[0017] c. Start the ozone generator and expose ozone to the wastewater of the electrolyzer through the aeration system;

[0018] d. Start the water pump. Under the action of negative pressure, the wastewater enters the pore structure inside the membrane from the cathode surface of the porous conductive carbon membrane assembly. The ozone dissolved in the water undergoes an electrocatalytic reaction to produce active substances such as hydroxyl free radicals with strong oxidizing ability, and oxidizes and degrades organic pollutants in the water into small molecules or detoxifies or mineralizes them into carbon dioxide and water, thereby achieving efficient removal of organic matter. The treated wastewater returns to the electrolytic cell through the permeate outlet of the porous conductive carbon membrane assembly. After multiple cycles, effective treatment of the wastewater is achieved.

[0019] e. The treated wastewater is discharged through the wastewater outlet of the electrolytic cell;

[0020] f. The tail gas is discharged through the exhaust port and enters the ozone tail gas destructor for treatment.

[0021] In one embodiment of the present invention, the voltage of the DC power supply is 1.5-5.0V, the dosage of ozone is 50-300mg / L, and the flow rate of the water pump is 20-200Lm -2 h -1 , the salt content of the wastewater is 1-10g / L, the initial COD of the wastewater is 100-500mg / L, and the hydraulic retention time is 1-10h.

[0022] Furthermore, the optimal voltage of the DC power supply is 2.0-2.5V.

[0023] The advantages of the present invention are as follows:

[0024] (1) Compared with traditional electrocatalytic technology, the porous conductive carbon membrane assembly produces a large amount of hydroxyl radicals at a voltage below 3V, which improves the electrode operating life and saves energy;

[0025] (2) Compared with ordinary ozone O3 oxidation, the hydroxyl radicals produced by electric field catalysis have stronger oxidizing properties and can improve the pollutant removal effect;

[0026] (3) The design of the porous conductive carbon membrane assembly limits the electrocatalytic oxidation reaction of ozone to the inside of the membrane pores, thereby enhancing the mass transfer rate of ozone from the liquid phase to the electrode surface, increasing the utilization rate of ozone and the production of hydroxyl radicals, and ensuring that the effluent quality meets strict emission standards;

[0027] (4) It only consumes electrical energy, is easier to realize automatic control, and reduces the use of chemical agents, thus forming a new green process with high degree of intensiveness / modularity, low cost, environmental friendliness and sustainable development.

[0028] Compared with the prior art, the electrocatalytic membrane reactor coupled ozone device for treating organic wastewater of the present invention and the implementation method thereof are as follows: wastewater containing ozone and pollutants passes through the pore structure inside the porous conductive carbon membrane component under the negative pressure provided by a water pump; under the action of an electric field, ozone undergoes an electrocatalytic reaction to produce active substances such as hydroxyl free radicals with strong oxidizing properties, and oxidizes and degrades organic pollutants in the water into small molecules or detoxifies or mineralizes them into carbon dioxide and water, thereby achieving efficient removal of organic matter; the electrocatalytic reaction of ozone is confined to the pores inside the porous conductive carbon membrane component, thereby increasing the mass transfer rate of ozone in the solution to the electrode surface, thereby increasing the pollutant removal effect and ozone utilization rate, and can effectively treat membrane-making wastewater, cleanly and without secondary pollution, thereby achieving the purpose of the present invention.

[0029] The features of the present invention can be clearly understood by referring to the drawings and the following detailed description of the preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of an electrocatalytic membrane reactor coupled with an ozone reaction device of the present invention;

[0031] Figure 2 It is a schematic diagram of the structure of the porous conductive carbon membrane of the present invention;

[0032] Figure 3 It is a schematic diagram of electron microscope scanning of the porous conductive carbon membrane of the present invention;

[0033] Figure 4 It is a schematic diagram of the COD and TN removal rates of membrane wastewater treated by using an electrocatalytic membrane reactor coupled with an ozone reaction device in the embodiment;

[0034] Figure 5 It is a schematic diagram of the removal rates of COD and TN in membrane wastewater treated by three different processes: ozone, electrocatalytic oxidation, and electrocatalytic membrane reactor coupled with ozone;

[0035] Figure 6 Schematic diagram of the COD removal effect of electrocatalytic membrane reactor coupled with ozone process in R0 concentrated liquid of printing and dyeing wastewater.

[0036] Explanation of symbols: 11-electrolyzer; 12-porous conductive carbon membrane assembly; 13-ozone generator; 14-aeration system; 15-exhaust gas destroyer; 16-water pump; 17-DC power supply; 111-wastewater inlet; 112-wastewater outlet; 113-exhaust outlet; 114-air inlet; 121-porous conductive carbon membrane; 122-graphite plate; 123-permeate outlet; 124-plastic bracket; 125-external circuit connecting wire; 1211. Acrylic seal. DETAILED DESCRIPTION

[0037] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below with reference to specific diagrams.

[0038] See also Figure 1 , Figure 2 and Figure 3 The electrocatalytic membrane reactor coupled ozone device for treating organic wastewater of the present invention comprises: an electrolytic cell 11, a porous conductive carbon membrane assembly 12, an ozone generator 13, an aeration system 14, a tail gas destroyer 15, a water pump 16 and a DC power supply 17.

[0039] The electrolytic cell 11 is provided with a wastewater inlet 111, a wastewater outlet 112, an exhaust port 113 and an air inlet 114; a plurality of porous conductive carbon membrane components 12 and an aeration system 14 are provided in the electrolytic cell 11, the aeration system 14 is arranged at the bottom of the electrolytic cell 11, the aeration system 14 is connected to the ozone generator 13, and the exhaust port 113 of the electrolytic cell 11 is connected to the ozone tail gas destroyer 15; the cathode of the porous conductive carbon membrane component 12 is connected to the negative electrode of the DC power supply 17 through an external circuit connection line, the anode of the porous conductive carbon membrane component 12 is connected to the positive electrode of the DC power supply 17 through an external circuit connection line, the permeate outlet 123 of the porous conductive carbon membrane component 12 is connected to the water inlet end of the water pump 16, and the water outlet end of the water pump 16 is connected to the wastewater inlet 111 of the electrolytic cell 11.

[0040] The cathode of the porous conductive carbon membrane assembly 12 is a plurality of porous conductive carbon membranes 121 ( Figure 3 ), the anode of the porous conductive carbon membrane assembly 12 is a graphite plate 122, and the distance between the cathode of the porous conductive carbon membrane assembly 12 and the anode of the porous conductive carbon membrane assembly 12 is 1-3 cm.

[0041] The porous conductive carbon membrane 121 is made of activated carbon material and is encapsulated in an acrylic seal 1211. The acrylic seal 1211 is provided with an external circuit connection line 125 and a permeate outlet 123. The permeate outlet 123 is connected to the water inlet end of the water pump 16, and the water outlet end of the water pump 16 is connected to the wastewater inlet 111 of the electrolytic cell 11.

[0042] The cathode of the porous conductive carbon membrane assembly 12 and the anode of the porous conductive carbon membrane assembly 12 are fixed to the plastic bracket 124 by plastic screws.

[0043] The aeration system 14 includes, but is not limited to, an aeration disk aeration system and an ejector aeration system.

[0044] The external circuit connecting wire 125 is made of TA2 titanium material.

[0045] The method for implementing the electrocatalytic membrane reactor coupled with the ozone device for treating organic wastewater of the present invention comprises the following steps:

[0046] a. The membrane wastewater is transported into the electrolytic cell 11 through the wastewater inlet 111;

[0047] b. Start the DC power supply 17 and apply positive and negative voltages to the anode and cathode of the porous conductive carbon membrane assembly 12 in the electrolytic cell 11, respectively;

[0048] c. Start the ozone generator 13 and expose ozone to the wastewater in the electrolyzer 11 through the aeration system 14;

[0049] d. Start the water pump 16. Under the action of negative pressure, the wastewater enters the pore structure inside the membrane from the cathode surface of the porous conductive carbon membrane assembly 12. The ozone dissolved in the water undergoes an electrocatalytic reaction to produce active substances such as hydroxyl free radicals with strong oxidizing ability, and oxidizes and degrades organic pollutants in the water into small molecules or detoxifies or mineralizes them into carbon dioxide and water, thereby achieving efficient removal of organic matter; the treated wastewater returns to the electrolytic cell 11 through the permeate outlet 123 of the porous conductive carbon membrane assembly 12, and the effective treatment of the wastewater is achieved after multiple cycles;

[0050] e. The treated wastewater is discharged through the wastewater outlet 112 of the electrolytic cell 11;

[0051] f. The tail gas is discharged through the exhaust port 113 and enters the ozone tail gas destroyer 15 for treatment.

[0052] The voltage of the DC power supply 17 is 1.5-5.0V, the dosage of ozone is 50-300mg / L, and the flow rate of the water pump 16 is 20-200Lm -2 h -1 , the salt content of the wastewater is 1-10g / L, the initial COD of the wastewater is 100-500mg / L, and the hydraulic retention time is 1-10h. The optimal voltage of the DC power supply 17 is 2.0-2.5V.

[0053] Example 1

[0054] like Figure 4 As shown, the wastewater selected in this embodiment comes from the MBR effluent of membrane-making wastewater generated by a membrane-making enterprise.

[0055] The characteristics of the original wastewater are as follows: pH = 7 ± 0.05, COD = 120 ± 20 mg / L, TN = 41 ± 10 mg / L, the salt content of the wastewater is 10 g / L, and the water volume is 20 T / d. The voltage applied by the DC power supply 17 is 2.5 V, the ozone dosage is 150 mg / L, and the flow rate of the water pump 16 is controlled at 120 L m -2 h -1Under the condition of hydraulic retention time of 2h, the average removal rate of COD in membrane wastewater reached 84%, and the average removal rate of TN reached 39%. The effluent COD = 20±10mg / L, TN = 25±5mg / L, which met the requirements of the "Synthetic Resin Industry Pollutant Emission Standard" (GB 31572-2015) implemented by the company's park, that is, COD concentration is less than 60mg / L, TN concentration is less than 30mg / L.

[0056] Example 2

[0057] like Figure 5 As shown, this embodiment provides a method for treating membrane wastewater using ozone, electrocatalytic oxidation, and electrocatalytic membrane reactor coupled with ozone. The wastewater selected in this embodiment comes from the membrane wastewater MBR effluent generated by a membrane enterprise.

[0058] The characteristics of the original wastewater were measured as follows: pH = 7 ± 0.05, COD = 120 ± 20 mg / L, TN = 41 ± 10 mg / L, wastewater salt content of 10 g / L, water volume of 20 T / d. Among them, the ozone process controls the ozone dosage to 150 mg / L and the hydraulic retention time to 2 h; the electrocatalytic oxidation process controls the voltage to 2.5 V and the hydraulic retention time to 2 h; the electrocatalytic membrane reactor coupled ozone process controls the voltage to 2.5 V, the ozone dosage to 150 mg / L, and the flow rate of the water pump 16 is controlled at 120 L m -2 h -1 , the hydraulic retention time is 2h.

[0059] The results showed that after 2 hours, the COD and TN removal rates of the ozone process were 20% and 10%, respectively, the average COD and TN removal rates of the electrocatalytic oxidation process were 5% and 3%, respectively, and the average COD and TN removal rates of the electrocatalytic membrane reactor coupled with the ozone process were 84% and 39%, respectively. Among the three processes, only the electrocatalytic membrane reactor coupled with the ozone process reached the enterprise emission standards. This shows that the electrocatalytic membrane reactor coupled with ozone has a good synergistic effect and can improve the treatment effect of ozone or electrocatalytic oxidation alone on membrane wastewater.

[0060] Example 3

[0061] like Figure 6 As shown, the present application provides an embodiment of a method for treating R0 concentrated liquid of printing and dyeing wastewater using ozone, electrocatalytic oxidation, and electrocatalytic membrane reactor coupled with ozone. The wastewater selected in this embodiment is from R0 concentrated liquid of printing and dyeing wastewater from a printing and dyeing factory in Zhejiang.

[0062] The characteristics of the original wastewater were measured as follows: pH = 7 ± 0.05, COD = 600 ± 50 mg / L, and the salt content of the wastewater was 30 g / L. Among them, the ozone process controlled the ozone dosage to be 150 mg / L and the hydraulic retention time to be 4 to 6 hours; the electrocatalytic oxidation process controlled the voltage to be 2.5 V and the hydraulic retention time to be 2 hours; the electrocatalytic membrane reactor coupled ozone process controlled the voltage to be 2.5 V, the ozone dosage to be 150 mg / L, and the flow rate of the water pump 16 was controlled at 120 L m -2 h -1 , the hydraulic retention time is 2h.

[0063] The results showed that after 2 hours, the COD removal rates of the three processes of ozone, electrocatalytic oxidation and electrocatalytic membrane reactor coupled with ozone were 20±10%, 8±5% and 88±10%, respectively. This shows that the electrocatalytic membrane reactor coupling can effectively remove the difficult-to-degrade pollutants in the wastewater of the printing and dyeing industry and achieve good treatment effects.

[0064] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected, and the scope of the present invention to be protected is defined by the attached claims and their equivalents.

Claims

1. An electrocatalytic membrane reactor coupled with an ozone device for treating organic wastewater and a method for implementing the same, characterized in that: It comprises an electrolytic cell, a porous conductive carbon membrane component, an ozone generator, an aeration system, an ozone tail gas destroyer, a water pump and a DC power supply; the electrolytic cell is provided with a wastewater inlet, a wastewater outlet, an exhaust port and an air inlet; a plurality of porous conductive carbon membrane components and an aeration system are provided in the electrolytic cell, the aeration system is provided at the bottom of the electrolytic cell, the aeration system is connected to the ozone generator, and the exhaust port of the electrolytic cell is connected to the ozone tail gas destroyer; the cathode of the porous conductive carbon membrane component is connected to the negative electrode of the DC power supply through an external circuit connecting line, the anode of the porous conductive carbon membrane component is connected to the positive electrode of the DC power supply through an external circuit connecting line, the permeate outlet of the porous conductive carbon membrane component is connected to the water inlet end of the water pump, and the water outlet end of the water pump is connected to the wastewater inlet of the electrolytic cell.

2. The electrocatalytic membrane reactor coupled with an ozone device for treating organic wastewater according to claim 1, characterized in that: The cathode of the porous conductive carbon membrane assembly is a plurality of porous conductive carbon membranes with an average pore size of 100-500nm, the anode of the porous conductive carbon membrane assembly is a graphite plate, and the distance between the cathode of the porous conductive carbon membrane assembly and the anode of the porous conductive carbon membrane assembly is 1-3cm.

3. The electrocatalytic membrane reactor coupled with an ozone device for treating organic wastewater according to claim 2, characterized in that: The porous conductive carbon membrane is made of activated carbon material and is encapsulated in an acrylic seal. The acrylic seal is provided with an external circuit connection line and a permeate outlet. The permeate outlet is connected to the water inlet of a water pump, and the water outlet of the water pump is connected to the wastewater inlet of the electrolytic cell.

4. The electrocatalytic membrane reactor coupled with an ozone device for treating organic wastewater according to claim 1, characterized in that: The cathode of the porous conductive carbon membrane assembly and the anode of the porous conductive carbon membrane assembly are fixed on the plastic bracket by plastic screws.

5. The electrocatalytic membrane reactor coupled with an ozone device for treating organic wastewater according to claim 1, characterized in that: The aeration system includes but is not limited to an aeration plate aeration system and an ejector aeration system.

6. The electrocatalytic membrane reactor coupled with an ozone device for treating organic wastewater according to claim 1, characterized in that: The external circuit connecting wire is made of TA2 titanium material.

7. A method for treating organic wastewater by coupling an electrocatalytic membrane reactor with an ozone device, characterized in that: The steps include: a. Transporting membrane wastewater into the electrolytic cell through the wastewater inlet; b. Start the DC power supply and apply positive and negative voltages to the anode and cathode of the porous conductive carbon membrane assembly in the electrolytic cell respectively; c. Start the ozone generator and expose ozone to the wastewater of the electrolyzer through the aeration system; d. Start the water pump. Under the action of negative pressure, the wastewater enters the pore structure inside the membrane from the cathode surface of the porous conductive carbon membrane assembly. The ozone dissolved in the water undergoes an electrocatalytic reaction to produce active substances such as hydroxyl free radicals with strong oxidizing ability, and oxidizes and degrades organic pollutants in the water into small molecules or detoxifies or mineralizes them into carbon dioxide and water, thereby achieving efficient removal of organic matter. The treated wastewater returns to the electrolytic cell through the permeate outlet of the porous conductive carbon membrane assembly. After multiple cycles, effective treatment of the wastewater is achieved. e. The treated wastewater is discharged through the wastewater outlet of the electrolytic cell; f. The tail gas is discharged through the exhaust port and enters the ozone tail gas destructor for treatment.

8. The method for implementing the electrocatalytic membrane reactor coupled with an ozone device for treating organic wastewater according to claim 7, characterized in that: The voltage of the DC power supply is 1.5-5.0V, the dosage of ozone is 50-300mg / L, and the flow rate of the water pump is 20-200Lm -2 h -1 , the salt content of the wastewater is 1-10g / L, the initial COD of the wastewater is 100-500mg / L, and the hydraulic retention time is 1-10h.

9. The method for implementing the electrocatalytic membrane reactor coupled with an ozone device for treating organic wastewater according to claim 8, characterized in that: The optimal voltage of the DC power supply is 2.0-2.5V.

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