CN110526348A - A kind of film filtering-electro-catalysis sewage water treatment method - Google Patents

Abstract

The invention belongs to the technical field of sewage treatment, in particular to a membrane filtration-electrocatalytic sewage treatment method. The membrane filtration-electrocatalysis sewage treatment method provided by the present invention comprises the following steps: connecting the conductive porous membrane and the counter electrode to an external power supply, driven by the pressure difference, the sewage flows through the conductive porous membrane to perform membrane filtration-electrocatalysis to obtain Purify water. In the present invention, membrane separation and electrocatalysis are coupled in situ, and the driving energy consumed by the membrane filtration process is used as the driving force for mass transfer in the electrocatalysis process at the same time, realizing efficient utilization of energy without equipment input, through the advantages of electrocatalysis and membrane processes Complementary, it overcomes the shortcomings of the membrane filtration process and the electrocatalytic process, and improves the overall energy utilization efficiency and pollutant treatment efficiency.

Description

A membrane filtration-electrocatalytic sewage treatment method

technical field

The invention relates to the technical field of sewage treatment, in particular to a membrane filtration-electrocatalytic sewage treatment method.

Background technique

Membrane technology has been widely used in the field of water and wastewater treatment. At present, the membrane technologies applied in the field of water treatment mainly include microfiltration, ultrafiltration, nanofiltration, electrodialysis and reverse osmosis. Among them, microfiltration and ultrafiltration technology are mainly used for the removal of particulate matter, floc, bacteria and turbidity and for membrane-bioreactors, nanofiltration and reverse osmosis are mainly used for the removal of salts, viruses and some organic pollution in water things. The membrane process is a pressure-driven process. In the order of microfiltration, ultrafiltration, nanofiltration, and reverse osmosis, the transmembrane pressure difference increases sequentially, from a few atmospheres of microfiltration to dozens of atmospheres of reverse osmosis. For the pressure head loss caused by the transmembrane pressure difference in the membrane process, if it is not recovered, it will mean a large amount of energy loss, and energy recovery requires a large amount of equipment investment, so currently only large-scale reverse osmosis devices have energy Complementary recycling equipment.

Microfiltration, ultrafiltration and nanofiltration have been well promoted in the field of wastewater treatment due to their high filtration accuracy and stable effluent quality, and combined with biological treatment, a membrane-bioreactor has been developed, which degrades organic pollutants by microorganisms and membrane filtration Ensure the turbidity and microbial indicators of the effluent. However, energy consumption is still one of the main problems limiting the promotion of microfiltration, ultrafiltration and nanofiltration membrane technologies. In addition to the head loss across the membrane, membrane fouling causes a decrease in membrane flux, requires regular backflushing and chemical cleaning, and increases process operating costs.

Electrocatalytic oxidation is one of the advanced oxidation technologies that has developed rapidly in recent years. Due to its high efficiency, strong controllability, no or little secondary pollution, mild conditions (can be carried out at room temperature), reactors and operating equipment Simple and easy to combine with other processes, the application of this emerging advanced oxidation technology in purifying water pollutants has aroused great interest of scientists. Using ruthenium/titanium electrode as anode can effectively remove bacteria and algae in water [WY Liang, JH Qu, _LBChen , HJ Liu, PJ Lei. .Technol.2005,39:4633-4639; Wu Xingwu, Gao Tingyao, Li Guojian. Electrochemical water treatment new technology - sterilization and algae. Environmental Science Journal, 2000, 20s: 75-79], no secondary pollution. Boron-doped diamond film-titanium oxide photoelectrocatalytic electrode with PN structure shows high efficiency in the degradation of acid orange (Ⅱ) and 2,4-dichlorophenol [Jiuhui Qu, and XuZhao. Design of BDD-TiO ₂ Hybrid Electrode with PN Function for Photoelectrocatalytic Degradation of Organic Contaminants.Environ.Sci.Technol.,2008,42(13),4934-4939]; ruthenium-titanium electrode and lead oxide/titanium electrode applied to synthetic leather wastewater treatment [MPanizza and G Ceresola.Electrochemical Oxidation as a final treatment of synthetic tannery wastewater.Environ.Sci.Technol.2005,38:5470-5475], can effectively remove COD, chroma, tannic acid and ammonium salt. Electrocatalytic oxidation shows good application prospects in the removal of phenols, nitrobenzene, aniline and other organic pollutants [Wu Xingwu, Zhao Guohua, Gao Tingyao. New technology of electrochemical water treatment-degradation of organic wastewater. Journal of Environmental Science, 2000, 20s:80-84; B Nasr, G Abdellatif, P C Sáez, J Lobato, and MA Rodrigo. Electrochemical Oxidation of Hydroquinone, Resorcinol, and Catechol on Boron-Doped Diamond Anodes. Environ. Sci. Technol. 2005, 39, 7234-7239; M Mitadera, NS Spataru and A Fujishima. Electrochemical oxidation of aniline at boron-dopeddiamond electrodes. Journal of Applied Electrochemistry, 2004, 34:249-254; P J. Lobato, R Paz, MA Rodrigo, C Sáez. Electrochemical oxidation of phenolic wastes with boron-doped diamond anodes. Water Research, 2005, 39:2687-2703; Lynne Wallace, Michael P. Cronin, Anthony I. Day, and Damian P .Buck.Electrochemical Method Applicable to Treatment of Wastewater from Nitrotriazolone Production.Environ.Sci.Technol.,Article ASAP DOI:10.1021/es8028878.Publication Date(Web):06February 2009], also in the treatment of printing and dyeing wastewater that is difficult to biodegrade [X Chen, G Chen, PL Yue. Anodic oxidation of dyes at novel Ti/B-diamond electrodes. Chemical Engineering Science. 2003, 58:995-1001; A Wang, J Qu, H Liu, J Ge. Degradation of azo dye Acid Red 14 in aqueous solution by electrokinetic and electrooxidation process. Chemosphere, 2004, 55: 1189-1196].

Although the electrocatalytic oxidation technology shows good application prospects, the low current efficiency has always restricted its commercialization. At present, the research on electrocatalytic oxidation mainly focuses on the research of new materials for high-efficiency electrodes, the exploration of reaction mechanism, the exploration of new application fields and the research of high-efficiency reactors, among which electrodes such as diamond film electrodes and multi-element titanium-based noble metal oxide electrodes The material exhibits good stability and high efficiency, and the three-dimensional electrode reactor greatly improves the reactor efficiency. Recent studies have shown that the efficiency of electrocatalytic oxidation degradation of organic pollutants is related to free hydroxyl radicals, and the higher the concentration of free hydroxyl radicals, the higher the pollutant degradation efficiency [Xiuping Zhu, Meiping Tong, Shaoyuan Shi, Huazhang Zhao, and Jinren Ni.Essential Explanation of the Strong Mineralization Performance of Boron-Doped Diamond Electrodes.Environ.Sci.Technol.,2008,42(13),4914-4920], however, free hydroxyl radicals will inevitably have some It is transformed into oxygen evolution, and hydrogen evolution reaction cannot be avoided at the same time. The gassing side reaction produced by the electrolysis of water is one of the main reasons for the unsatisfactory energy efficiency of the electrocatalytic oxidation process. Although some processes are designed to use gassing as an electric floatation process, the energy efficiency is not ideal. The same problem exists in the electrocatalytic reduction process.

In summary, the existing water treatment methods all have the disadvantages of high energy consumption and low efficiency.

Contents of the invention

The purpose of the present invention is to provide a membrane filtration-electrocatalysis sewage treatment method to realize energy-efficient and process-efficient sewage treatment.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The invention provides a membrane filtration-electrocatalytic sewage treatment method, comprising the following steps:

The conductive porous membrane and the counter electrode are connected to an external power supply, driven by the pressure difference, the sewage flows through the conductive porous membrane for membrane filtration-electrocatalysis to obtain purified water.

Preferably, the average pore diameter of the conductive porous membrane is 0.8 nm˜2 μm.

Preferably, when the purpose of purifying the sewage is to remove salt in water, the pore diameter of the conductive porous membrane is 0.8-100 nm.

Preferably, the conductive porous film includes a porous metal film, a porous carbon film, a porous carbide film, a conductive porous metal oxide film, a porous conductive polymer film, a porous conductive composite film, a surface-modified porous conductive film, or a porous conductive film through pores. A porous conductive membrane loaded with catalytically active components.

Preferably, the counter electrode includes a metal, an intermetallic compound, a carbide, a conductive metal oxide, a carbon electrode or a conductive porous film as described in the above technical solution.

Preferably, the counter electrode is arranged on the upstream side or the downstream side of the conductive porous membrane.

Preferably, the working voltage of the external power supply is set to be -10-10V.

Preferably, when the sewage flows through the conductive porous membrane, a to-be-purified area and a purified area are formed, the to-be-purified area is the sewage water inflow area, and the purification area is the purified water outflow area.

Preferably, the sewage, the conductive porous membrane and the purified water are arranged in sequence according to the direction of water flow.

The invention provides a membrane filtration-electrocatalysis sewage treatment method, comprising the following steps: connecting the conductive porous membrane and the counter electrode to an external power source, driven by the pressure difference, the sewage flows through the conductive porous membrane to perform membrane filtration-electrocatalysis , to obtain purified water. The present invention uses the conductive porous membrane as the electrode to form an electrocatalytic membrane reactor. During the membrane filtration process, an electric field is applied, and the membrane acts as the anode or cathode of the electric field to realize the filtration function and retain particulate pollutants and flocs. When the permeate flows through the conductive When the pores of the porous membrane are used, the dissolved pollutants are electrocatalytically decomposed on the inner surface of the membrane pores, realizing the coupling of membrane filtration and electrocatalysis, and simultaneously removing particulate pollutants and dissolved pollutants.

In the present invention, membrane separation and electrocatalysis are coupled in situ, and the driving energy consumed by the membrane filtration process (such as the energy provided by a water pump) is simultaneously used as the driving force for mass transfer in the electrocatalysis process, thereby realizing efficient utilization of energy without equipment input, through The advantages of electrocatalysis and membrane process complement each other, overcome the shortcomings of membrane filtration process and electrocatalysis process, and improve the overall energy utilization efficiency and pollutant treatment efficiency.

Description of drawings

Fig. 1 is the schematic diagram of the principle of membrane filtration-electrocatalytic sewage treatment of the present invention; Wherein, 1-porous conductive membrane, 2-counter electrode;

Fig. 2 is the reactor that carries out membrane filtration-electrocatalysis in embodiment 1～4 of the present invention;

Fig. 3 is the reactor that carries out membrane filtration-electrocatalysis for embodiment 5 of the present invention;

Fig. 4 is the reactor that carries out membrane filtration-electrocatalysis in embodiment 6 of the present invention;

Fig. 5 is a reactor for membrane filtration-electrocatalysis in Examples 7-8 of the present invention.

Detailed ways

The invention provides a membrane filtration-electrocatalytic sewage treatment method, comprising the following steps:

The conductive porous membrane and the counter electrode are connected to an external power supply, driven by the pressure difference, the sewage flows through the conductive porous membrane for membrane filtration-electrocatalysis to obtain purified water.

In the present invention, unless otherwise specified, the required raw materials or parts are commercially available products well known to those skilled in the art.

In the invention, the conductive porous membrane, the external power supply and the counter electrode are sequentially connected. In the present invention, the conductive porous film preferably includes a porous metal film, a porous carbon film, a porous carbide film, a conductive porous metal oxide film, a porous conductive polymer film, a porous conductive composite film, and a surface-modified porous conductive film. Or through a porous conductive membrane loaded with catalytically active components in the pores. In the embodiment of the present invention, it may specifically be a tubular carbon membrane, a titanium membrane, a flat carbon membrane, a carbon membrane loaded with 1.2% RuO ₂ or a carbon membrane loaded with a palladium/copper alloy catalyst.

The present invention has no special limitation on the external power supply, as long as it can provide a stable voltage. In the present invention, preferably, the operating voltage of the external power supply is set to be -10-10V, more preferably -0.2-8V, and most preferably -0.1-6V.

In the present invention, the counter electrode preferably includes metal, intermetallic compound, carbide, conductive metal oxide, carbon electrode or conductive porous film, and the conductive porous film is preferably the conductive porous film described in the above technical solution. In an embodiment of the present invention, the counter electrode is specifically a stainless steel, graphite plate or carbon electrode; the counter electrode is arranged on the upstream or downstream side of the conductive porous membrane. In the present invention, the counter electrode is preferably disposed on the upstream or downstream side of the conductive porous membrane according to the direction of water permeation through the membrane, and the conductive porous membrane, external power supply, counter electrode and water form a current loop.

The method of connecting the conductive porous membrane and the counter electrode to the external power source is not particularly limited in the present invention, and an electrical connection method well known to those skilled in the art can be selected.

After the conductive porous membrane and the counter electrode are connected to an external power supply, driven by the pressure difference, the sewage flows through the conductive porous membrane for membrane filtration-electrocatalysis to obtain purified water. In the present invention, there is no special limitation on the source of the pressure difference, and a device that can provide the pressure difference well known to those skilled in the art can be selected. In the embodiment of the present invention, the pressure difference drive is specifically provided by a water pump or a vacuum pump. .

In the present invention, when the sewage flows through the conductive porous membrane, an area to be purified and a purified area are formed, the area to be purified is the sewage water inlet area, and the purified area is the purified water outflow area. In the present invention, after the sewage flows through the conductive porous membrane, the membrane body divides the sewage into two isolated areas, the area to be purified and the purification area; the sewage, the conductive porous membrane and the purified water are preferably arranged in sequence according to the flow direction. In the present invention, the area to be purified is a sewage water inlet area, and the sewage contains particulate pollutants, flocs, macromolecular pollutants, salts and small molecular pollutants; the purified area is a purified water outflow area, Purified water is water obtained after purification. During the process of sewage flowing through the conductive porous membrane, the conductive porous membrane intercepts and removes particulate pollutants, flocs and macromolecular substances in the sewage; while the permeable pollutants (salts and small molecule pollutants) that are not trapped The pores, surface or outside of the porous membrane are partially or completely decomposed or degraded to generate harmless carbon dioxide, water or nitrogen through electrocatalytic oxidation or reduction.

In the present invention, the problem of membrane fouling inevitably exists in the membrane filtration process, and the pollutants in the intercepted water cover the membrane surface, which will reduce the membrane flux. The present invention preferably adopts regular chemical cleaning and gas (or water) recoil cleaning Membrane surface to prevent membrane fouling from affecting treatment efficiency. In addition, in the electrocatalysis process using conductive membranes as electrodes, gas evolution can also clean the membrane surface, reduce concentration polarization, prevent membrane fouling, and realize efficient utilization of energy consumed by gas evolution side reactions; Moreover, electrocatalysis can decompose organic pollutants deposited on the surface of the membrane, combined with the control of gas evolution side reactions, the membrane can also be cleaned, further saving energy.

In the present invention, the average pore diameter of the conductive porous membrane is preferably 0.8 nm to 2 μm, more preferably 0.8 nm to 1 μm, and most preferably 0.8 to 800 nm. The invention can realize high-efficiency catalysis by controlling the pore size of the conductive porous membrane, combining membrane filtration and electrocatalytic reaction.

In the present invention, when the purpose of purifying the sewage is to remove salt in water, the pore diameter of the conductive porous membrane is preferably 0.8-100 nm, more preferably 0.8-60 nm, most preferably 0.8-50 nm. When treating salty sewage, the salt ions are intercepted by the confinement effect of the pores on the conductive porous membrane, and the ions with the same charge as the membrane electrode are strongly intercepted under the action of the electric field. The invention controls the pore diameter of the conductive porous membrane to be nanoscale, utilizes the confinement effect produced by the membrane to perform desalination, and after applying an electric field to the conductive porous membrane, the repulsion of the electric field and the confinement desalination effect can further improve the desalination efficiency.

The present invention selects a conductive porous membrane with a smaller pore size. When the sewage flows through the pores in the membrane, the chance of contact between the pollutants and the pore wall (membrane electrode inner surface) will be increased, the ratio of "electrode area/pollutant quantity" will be improved, and the single-pass reaction will be improved. efficiency.

Figure 1 is a schematic diagram of the principle of membrane filtration-electrocatalytic sewage treatment of the present invention, as shown in the figure, 1-conductive porous membrane, 2-counter electrode. The present invention uses the conductive porous membrane 1 as the electrode (i.e. the anode or cathode of the electric field), constitutes an electrocatalytic membrane reactor with the counter electrode 2 and an external power supply, applies an electric field during the membrane filtration process, and the sewage flows through the conductive porous membrane to form an electrocatalytic membrane reactor to be purified. zone and purification zone, the conductive porous membrane realizes the filtering function and intercepts particulate pollutants and flocs. When passing through the membrane pores, the dissolved pollutants undergo electrocatalytic decomposition on the inner surface of the conductive porous membrane to realize membrane filtration. Coupled with electrocatalysis, particulate pollutants and dissolved pollutants are removed simultaneously to obtain purified water.

The present invention has no special limitations on the structure of the reactor used in the membrane filtration-electrocatalytic sewage treatment method, as long as it can meet the structural requirements of the above-mentioned technical solution. In the embodiments of the present invention, the specific structure of the reactor used can be found in 2 to 5, the specific structures are described in related examples, but these reactor structures do not limit the methods described in the examples, and the schemes of the examples of the present invention can still be implemented by selecting reactors with other structures.

The present invention has no special limitation on the treatment conditions of the membrane filtration-electrocatalysis (such as transmembrane pressure difference, water temperature, membrane surface flow rate, etc.), and can be adjusted according to the structure of the reactor used.

The technical solutions in the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Embodiments 1 to 4 use the reactor shown in Figure 2 to carry out membrane filtration-electrocatalytic sewage treatment, wherein, 3-raw water tank; 4-water pump; 5-insulating sealing ring; 6-conductive porous membrane; 7-counter electrode; 8 -purified water outlet; 9-stop valve; 10-power supply.

The process of sewage treatment using the device shown in Figure 2 is: turn on the power supply 10, apply a voltage on the conductive porous membrane 6 and the outer shell of the counter electrode 7, the sewage enters the area to be purified, and flows through the conductive porous membrane 6 driven by the differential pressure of the water pump 4 , carry out membrane filtration-electrocatalysis, the obtained purified water enters the purification zone, flows out through the purified water outlet 8 and is collected through the counter electrode shell outside the membrane; wherein, particulate matter, flocs and macromolecular pollutants are filtered and intercepted, and the permeability pollution When substances pass through the membrane pores or contact the membrane surface, they are oxidized or reduced to harmless substances by electrocatalysis, and the bubbles generated on the electrode surface due to electrolysis of water can delay or inhibit membrane fouling.

Example 1

A tubular carbon membrane with an average pore size of 0.56 μm is used as the conductive porous membrane (anode), and stainless steel is used as the pressure shell and also serves as the cathode (counter electrode) to form a cross-flow filtration electrocatalytic membrane reactor. The depth of the effluent of a sewage treatment plant deal with. Set treatment conditions: transmembrane pressure difference 0.1MPa, membrane surface flow velocity 1.95-2.05m·s ^-1 , water temperature 25-32°C, working voltage 5V.

Influent water quality (sewage) indicators are: yellowish, smelly, COD 60~320 (mg·L ^-1 ), ammonia nitrogen 4~27 (mg·L ^-1 ), turbidity 18~155 (NTU), pH value 6~9.

The results show that under the condition of no electricity, the filtration flux is 0.04m ³ .m ^-2 .h ^-1 , the removal rate of COD is 50.31%, the removal rate of ammonia nitrogen is 75%, and the removal rate of turbidity is 80%. After applying the electric field, the permeation flux increased by 100% to 0.08m ³ ·m ^-2 ·h ^-1 , the COD removal rate increased to 80%, the ammonia nitrogen removal rate exceeded 90%, the turbidity removal rate was 80%, and the effluent water quality reached the standard Miscellaneous water standards. This shows that the present invention combines membrane filtration and electrocatalysis technology, can significantly improve the sewage treatment effect, and can realize energy-efficient and process-efficient sewage treatment.

Example 2

A titanium membrane with a filtration accuracy of 0.2 μm is used as the conductive porous membrane (anode), and stainless steel is used as the pressure shell and doubles as the cathode (counter electrode) to form a cross-flow filtration electrocatalytic membrane reactor. The treatment conditions are set: transmembrane pressure difference 0.1MPa , the membrane surface flow rate is 3.2m·s ^-1 , the temperature is 20-28°C, the working voltage is 5V, the raw water is simulated wastewater, and the simulated wastewater contains 5% of fly ash with an average particle size of 2μm, 30mg·L ^-1 of phenol, Ammonia nitrogen 30mg·L ^-1 .

After treatment, the removal rate of fly ash is 100%, the removal rate of phenol is 83%, and the removal rate of ammonia nitrogen is 60%.

Example 3

A tubular carbon membrane with an average pore diameter of 2 μm is used as the conductive ^porous membrane (anode), and stainless steel is used as the pressure shell and double as the cathode (counter electrode). The difference is 0.1MPa, and the simulated wastewater is treated, wherein, the simulated wastewater contains 500mg·L ^-1 of phenol.

After treatment, the removal rate of phenol was 89%.

Example 4

A carbon membrane with an average pore size of 1nm is used as the conductive porous membrane (anode), and stainless steel is used as the pressure shell and double as the cathode (counter electrode). The treatment conditions are set: working voltage 3V, membrane surface flow rate 3m·s ^-1 , to treat simulated wastewater. Among them, the simulated wastewater contains 5% of fly ash with an average particle size of 2μm and 2000mg·L ^-1 of phenol.

After treatment, the removal rate of fly ash is 100%, and the removal rate of phenol is 100%.

Example 5

In this embodiment, the reactor shown in Figure 3 is used for membrane filtration-electrocatalytic sewage treatment, wherein, 11-raw water tank; 12-water pump; 13-raw water feed chamber; 14-insulating sealing ring; 15-conductive porous membrane; 16-counter electrode; 17-purified water collection tank; 18-stop valve; 19-power supply; the treatment process of the reactor is similar to the reactor shown in Figure 2.

The carbon film with the load of _1.2 % RuO with an average pore size of 8.3nm is used as the conductive porous film (anode), and the stainless steel is used as the cathode (counter electrode). The flat membrane cross-flow filtration mode is adopted, and the sewage is pushed to flow through the surface of the carbon film 15 by the water pump 12. Under the action of pressure difference, part of the water passes through the membrane to reach the space formed by the counter electrode 16, the conductive porous membrane 15 and the insulating sealing ring 14, and reaches the purified water tank 17 under the action of pressure, and the particles and flocs are trapped in the raw water feeding chamber 13 And it is brought back to the original water tank 11 by the cross-flow water; when the dissolved pollutants pass through the membrane, they are degraded under the action of electrocatalysis. Wherein, the quality of the raw water is the same as that in Example 1, and the treatment conditions are set: the cross-flow velocity is 2-2.5 m·s ^-1 , and the working voltage is 3.5V.

After treatment, the COD removal rate is 92%, the ammonia nitrogen removal rate is 100%, and the turbidity removal rate is 100%.

Example 6

In this embodiment, the reactor shown in Figure 4 is used for membrane filtration-electrocatalytic sewage treatment, wherein, 20-raw water tank; 21-power supply; 22-conductive porous membrane; 23-counter electrode; 24-spacer; 25-purification Water collection tank; 26 - vacuum pump.

The flat carbon film with average pore diameter of 20nm is the conductive porous film (anode), the graphite plate is the negative electrode (counter electrode), and the flat carbon film and the counter electrode are separated by a rubber sealing ring spacer and form a gap, and the reactor is placed In the raw water tank 20 (holding sewage), the suction effect of the vacuum pump 26 builds up the transmembrane pressure difference, and drives the sewage to pass through the membrane and enter the purified water collection tank 25 .

The treatment conditions were set: the working voltage was 0.4V, and the simulated brine was treated, wherein the simulated brine contained 500 mg·L ^-1 of sodium sulfate.

After treatment, the sulfate ion removal rate is 71%, and the sodium ion removal rate is 69%.

Example 7

In this embodiment, the reactor shown in Figure 5 is used for membrane filtration-electrocatalytic sewage treatment, wherein, 27-power supply, 28-raw water tank, 29-stirrer, 30-conductive porous membrane, 31-cation exchange membrane, 32- Anode chamber, 33-carbon counter electrode, 34-pressure sensor, 35-peristaltic pump, 36-purified water tank.

Adopting the tubular carbon film with average pore diameter of 8.3nm as the conductive porous film, the carbon electrode as the negative electrode (counter electrode), the cation exchange membrane 31 is set between the tubular carbon film and the counter electrode, and the tubular carbon film and the carbon counter electrode 33 are placed in a stirred tank. In the raw water tank 28, the suction of the peristaltic pump 35 drives the raw water (sewage) to pass through the membrane and enter the purified water tank 36; the processing conditions are set: the working voltage is 0.4V, the membrane surface flow rate is 3m·s ^-1 , and the simulated brine is treated , wherein the simulated brine contains 500mg·L ^-1 of sodium sulfate.

First, the tubular carbon membrane is used as the anode to process the simulated brine, and then the same device is used to treat the simulated brine with the tubular carbon membrane as the cathode.

After treatment, the sulfate ion removal rate is 94%, and the sodium ion removal rate is 91%.

Example 8

The carbon membrane that adopts average aperture 8.3nm and supports palladium/copper alloy catalyst is conductive porous membrane (anode), is negative electrode (counter electrode) with carbon electrode, according to the process described in embodiment 7, adopts reactor shown in Figure 5 to process nitric acid For salt nitrogen simulated wastewater, set the operating voltage to -4V; where the concentration of sodium nitrate in the simulated wastewater is 50mM.

After treatment, the removal rate of nitrate is 98%.

As can be seen from the above examples, the present invention provides a membrane filtration-electrocatalysis sewage treatment method. The present invention couples membrane separation and electrocatalysis in situ, and through the complementary advantages of electrocatalysis and membrane process, it overcomes the membrane filtration process and The shortcomings of the electrocatalytic process improve the overall energy utilization efficiency and pollutant treatment efficiency.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (9)

1. A membrane filtration-electrocatalytic sewage treatment method, is characterized in that, comprises the following steps: The conductive porous membrane and the counter electrode are connected to an external power supply, driven by the pressure difference, the sewage flows through the conductive porous membrane for membrane filtration-electrocatalysis to obtain purified water. 2 . The method according to claim 1 , wherein the average pore diameter of the conductive porous membrane is 0.8 nm˜2 μm. 3. The method according to claim 1, characterized in that, when the purpose of purifying the sewage is to remove salt in water, the pore diameter of the conductive porous membrane is 0.8-100 nm. 4. The method according to any one of claims 1 to 3, wherein the conductive porous film comprises a porous metal film, a porous carbon film, a porous carbide film, a conductive porous metal oxide film, a porous conductive polymer Membranes, porous conductive composite membranes, surface-modified porous conductive membranes or porous conductive membranes loaded with catalytically active components in pores. 5. The method according to claim 1, wherein the counter electrode comprises a metal, an intermetallic compound, a carbide, a conductive metal oxide, a carbon electrode or the conductive porous film according to claim 4. 6. The method according to claim 1 or 5, wherein the counter electrode is arranged on the upstream side or the downstream side of the conductive porous membrane. 7. The method according to claim 1, characterized in that the operating voltage of the external power supply is set to -10-10V. 8. The method according to claim 1, wherein, when the sewage flows through the conductive porous membrane, an area to be purified and a purified area are formed, the area to be purified is a sewage water inlet area, and the purified area is an area where purified water flows out area. 9. The method according to claim 1 or 8, characterized in that the sewage, the conductive porous membrane and the purified water are arranged in sequence according to the flow direction.