阅读说明：本技术 用于偶氮废水处理的厌氧生物阴极-电催化膜串联反应器 (Anaerobic biological cathode-electrocatalysis membrane series reactor for azo wastewater treatment ) 是由 莫颖慧 孙丽萍 李建新 于 2020-06-01 设计创作，主要内容包括：本发明公开了一种用于偶氮废水处理的厌氧生物阴极-电催化膜串联反应器,包括电解池,阳离子交换膜,阳、阴极室,电催化膜将阳极室分隔成阳极进、出水腔,阴极室内设置有填料和碳棒,直流电源通过导线与电催化膜和碳棒连接；阴极料液槽依次与第一蠕动泵和阴极室底部连接,阴极室顶部三支管道分别通过第一阀门、第二阀门、第三蠕动泵与阴极料液槽、阴极出水槽和阴极室底部连接；阴极出水槽依次与第二蠕动泵和阳极进水腔底部连接,阳极渗透液槽与阳极出水腔体顶部连接。本发明先通过阴极的生物电化学/电化学作用破坏偶氮染料分子中的偶氮键,降解中间产物再被阳极产生的羟基自由基(·OH)进一步氧化,具有偶氮脱色速率高、降解彻底等特点。(The invention discloses an anaerobic biological cathode-electrocatalysis membrane series reactor for azo wastewater treatment, which comprises an electrolytic cell, a cation exchange membrane, an anode chamber and a cathode chamber, wherein the electrocatalysis membrane divides the anode chamber into an anode water inlet cavity and an anode water outlet cavity; the cathode material liquid tank is sequentially connected with the first peristaltic pump and the bottom of the cathode chamber, and three pipelines at the top of the cathode chamber are respectively connected with the cathode material liquid tank, the cathode water outlet tank and the bottom of the cathode chamber through the first valve, the second valve and the third peristaltic pump; the cathode water outlet tank is sequentially connected with the second peristaltic pump and the bottom of the anode water inlet cavity, and the anode seepage tank is connected with the top of the anode water outlet cavity. According to the method, the azo bonds in azo dye molecules are firstly destroyed through the bioelectrochemistry/electrochemistry action of the cathode, the degraded intermediate products are further oxidized by hydroxyl free radicals (. OH) generated by the anode, and the method has the characteristics of high azo decolorization rate, complete degradation and the like.)

1. An anaerobic biological cathode-electrocatalysis membrane series reactor for azo wastewater treatment, which comprises an electrolytic cell (17) and is characterized in that a cation exchange membrane (6) is arranged in the electrolytic cell (17) to divide the electrolytic cell (17) into an anode chamber (7) and a cathode chamber (2), an electrocatalysis membrane (3) is arranged in the anode chamber (7) to divide the anode chamber (7) into an anode water inlet cavity (4) and an anode water outlet cavity (5), a filler (1) and a carbon rod (9) are arranged in the cathode chamber (2), and an adjustable direct current stabilized voltage power supply (8) is respectively connected with the electrocatalysis membrane (3) and the carbon rod (9) through leads; the cathode material liquid tank (10) is sequentially connected with a first peristaltic pump (14) and the bottom of the cathode chamber (2) through pipelines, the pipeline connected with the top of the cathode chamber (2) is divided into three branches, the first branch is sequentially connected with a first valve (12) and the cathode material liquid tank (10) through a pipeline, the second branch is connected with a cathode water outlet tank (11) through a second valve (13), and the third branch pipeline is connected with the bottom of the cathode chamber (2) through a third peristaltic pump (18); the cathode water outlet groove (11) is connected with the bottom of the anode water inlet cavity (4) through a second peristaltic pump (15), and the anode permeation groove (16) is connected with the top of the anode water outlet cavity (5) through a pipeline.

2. The reactor of claim 1, wherein the cation exchange membrane is a polyethylene cation exchange membrane, a polyphenylene ether cation exchange membrane or a vinylidene fluoride cation exchange membrane.

3. The reactor of claim 1, which isCharacterized in that the electrocatalytic film is MnO_x/Ti porous electrocatalytic film or TiO₂A Ti porous electrocatalytic membrane.

4. The reactor of claim 1, wherein the filler is graphite felt, activated carbon or semicoke.

5. The method for treating the azo wastewater is characterized by comprising the following steps:

1) use of the anaerobic biocathode-electrocatalytic membrane series reactor for azo wastewater treatment of one of claims 1 to 4;

2) injecting azo dye wastewater to be treated into a cathode water outlet tank (11), and injecting azo dye wastewater to be treated (in which a microorganism growth substrate is added) into a cathode material liquid tank (10);

3) opening a first peristaltic pump (14), a second peristaltic pump (15) and a first valve (12) to enable liquid in the cathode feed liquid tank (10) to circulate between the cathode chamber and the cathode feed liquid tank (10), pumping the liquid in the cathode water outlet tank (11) into the anode water inlet cavity (4), treating the liquid by the electro-catalytic membrane (3), then entering the anode water outlet cavity (5), and then discharging the liquid into the anode permeation tank (16) through a pipeline;

4) opening the adjustable direct current stabilized voltage power supply (8), and controlling the voltage to be 0.8-1.3V or the current to be 2-5 mA;

5) sludge is obtained from a municipal sewage plant or a bioelectrochemical system, the sludge and azo dye wastewater (in which a microorganism growth matrix is added) are mixed according to the volume ratio of (4-5) to 5 to obtain inoculation liquid, the liquid in a cathode material liquid tank (10) is replaced, and the cathode of the reactor is inoculated; replacing the inoculation liquid every 2-7 days, and finishing inoculation when the decolorizing efficiency of the cathode azo dye is increased and tends to be stable;

6) closing the first valve (12), opening the second valve (13) and the third peristaltic pump (18), injecting azo dye wastewater to be treated (in which a microorganism growth substrate is added) into the cathode feed liquid tank (10), allowing the azo dye wastewater to enter the cathode chamber (2) through the first peristaltic pump (14) for treatment, discharging treated cathode effluent from the top of the cathode chamber, returning a part of the cathode effluent to the cathode chamber (2) through the third peristaltic pump (18) for internal circulation, allowing the other part of the cathode effluent to flow into the cathode water outlet tank (11) through the second valve (13), allowing the cathode effluent in the cathode water outlet tank (11) to flow into the anode water inlet cavity (4) through the second peristaltic pump (15) for treatment, and finally discharging the cathode effluent into the anode permeate liquid tank (16) from the anode water outlet cavity (5).

6. The method of claim 5, wherein said microbial growth substrate comprises KH₂PO₄3-5g/L、K₂HPO₄·3H₂O2-4 g/L and glucose 0.8-1.0g/L, MgCl₂·6H₂O 0.08-0.24g/L、CaCl₂·2H₂O 0.08-0.24g/L、(NH₄)₂SO₄0.25-0.35g/L、MgSO₄0.02-0.04g/L、MnSO₄·H₂O 3-6mg/L、NaCl 8-16mg/L、FeSO₄·7H₂O 0.8-1.6mg/L、CoCl₂·6H₂O 0.8-1.6mg/L、ZnCl₂1-2mg/L、CuSO₄·5H₂O 0.1-0.2mg/L、AlK(SO₄)₂·7H₂O 0.1-0.2mg/L、H₃BO₃0.1-0.2mg/L、Na₂MoO₄0.5-1mg/L、NiCl₂·6H₂O0.3-0.6mg/L and Na₂WO₄·2H₂O 0.3-0.6mg/L。

Technical Field

The invention relates to the technical fields of bioelectrochemistry, electrocatalytic oxidation and membrane separation, in particular to an anaerobic biological cathode-electrocatalytic membrane series reactor for azo wastewater treatment.

Technical Field

With the development of dye chemical industry, azo dyes are widely applied to textile, leather and other industries, and azo dye wastewater is a major challenge in the field of environmental engineering due to the characteristics of high chroma, poor biodegradability, difficult degradability and the like. At present, biological treatment is taken as a main technology for treating azo dye wastewater, and the technological process mainly comprises the series connection of an anaerobic bioreactor for azo decolorization and an aerobic bioreactor for further oxidizing decolorization products. The anaerobic and aerobic series process can achieve better decolorization effect, but has some defects, for example, aromatic amine and other intermediate products generated after the azo dye wastewater is subjected to anaerobic treatment can generate toxic effect on microorganisms in the aerobic treatment.

At present, an integrated reactor combining an anaerobic process and an aerobic process into a whole has appeared. For example, chinese patent CN201720571624.8 discloses a wastewater treatment system coupling bioelectrocatalysis and photocatalytic contact oxidation, which degrades azo dye wastewater by gradient decreasing dissolved oxygen concentration, creating an anaerobic biological cathode/aerobic biological anode electrochemical system, and realizes deep mineralization of pollutants by photocatalytic oxidation. However, toxic intermediate products such as aromatic amine and the like in the system after anaerobic treatment can generate toxic action on anode microorganisms, and the diffusion of the dissolved oxygen of the anode to the cathode can influence the decolorization rate of the azo dye.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an anaerobic biological cathode-electrocatalytic membrane series reactor for azo wastewater treatment.

The second purpose of the invention is to provide a method for treating azo dye wastewater by using the reactor.

The technical scheme of the invention is summarized as follows:

an anaerobic biological cathode-electrocatalysis membrane series reactor for azo wastewater treatment, which comprises an electrolytic cell (17) and is characterized in that a cation exchange membrane (6) is arranged in the electrolytic cell (17) to divide the electrolytic cell (17) into an anode chamber (7) and a cathode chamber (2), an electrocatalysis membrane (3) is arranged in the anode chamber (7) to divide the anode chamber (7) into an anode water inlet cavity (4) and an anode water outlet cavity (5), a filler (1) and a carbon rod (9) are arranged in the cathode chamber (2), and an adjustable direct current stabilized voltage power supply (8) is respectively connected with the electrocatalysis membrane (3) and the carbon rod (9) through leads; the cathode material liquid tank (10) is sequentially connected with a first peristaltic pump (14) and the bottom of the cathode chamber (2) through pipelines, the pipeline connected with the top of the cathode chamber (2) is divided into three branches, the first branch is sequentially connected with a first valve (12) and the cathode material liquid tank (10) through a pipeline, the second branch is connected with a cathode water outlet tank (11) through a second valve (13), and the third branch pipeline is connected with the bottom of the cathode chamber (2) through a third peristaltic pump (18); the cathode water outlet groove (11) is connected with the bottom of the anode water inlet cavity (4) through a second peristaltic pump (15), and the anode permeation groove (16) is connected with the top of the anode water outlet cavity (5) through a pipeline.

Preferably, the cation exchange membrane is a polyethylene cation exchange membrane, a polyphenylene ether cation exchange membrane or a vinylidene fluoride cation exchange membrane.

Preferably, the electrocatalytic film is MnO_x/Ti porous electrocatalytic film or TiO₂A Ti porous electrocatalytic membrane.

Preferably, the filler is graphite felt, activated carbon or semicoke.

The method for treating the azo dye wastewater comprises the following steps:

1) the anaerobic biological cathode-electrocatalytic membrane series reactor for azo wastewater treatment is used;

2) injecting azo dye wastewater to be treated into a cathode water outlet tank 11, and injecting azo dye wastewater to be treated (in which a microorganism growth substrate is added) into a cathode material liquid tank 10;

3) opening a first peristaltic pump 14, a second peristaltic pump 15 and a first valve 12 to enable liquid in the cathode feed liquid tank 10 to circulate between the cathode chamber and the cathode feed liquid tank 10, pumping the liquid in the cathode water outlet tank 11 into the anode water inlet cavity 4, treating the liquid by the electro-catalytic membrane 3, then enabling the liquid to enter the anode water outlet cavity 5, and discharging the liquid into the anode permeation tank 16 through a pipeline;

4) the adjustable DC stabilized power supply 8 is turned on, the control voltage is 0.8-1.3V or the control current is 2-5 mA;

5) inoculation: sludge is obtained from a municipal sewage plant or a bioelectrochemical system, the sludge and azo dye wastewater (in which a microorganism growth matrix is added) are mixed according to the volume ratio of (4-5) to 5 to obtain inoculation liquid, the feed liquid in a cathode feed liquid tank 10 is replaced, and the cathode of the reactor is inoculated; replacing the inoculation liquid every 2-7 days, and finishing inoculation when the decolorizing efficiency of the cathode azo dye is increased and tends to be stable;

6) azo dye wastewater treatment: closing the first valve 12, opening the second valve 13 and the third peristaltic pump 18, injecting azo dye wastewater to be treated (in which a microorganism growth substrate is added) into the cathode feed liquid tank 10, allowing the azo dye wastewater to enter the cathode chamber 2 through the first peristaltic pump 14 for treatment, discharging the treated azo dye wastewater from the top of the cathode chamber, returning a part of cathode effluent to the cathode chamber 2 through the third peristaltic pump 18 for internal circulation, allowing the other part of the cathode effluent to flow into the cathode effluent tank 11 through the second valve 13, allowing the cathode effluent in the cathode effluent tank 11 to flow into the anode water inlet chamber 4 through the second peristaltic pump 15 for treatment, and finally discharging the cathode effluent from the anode effluent chamber into the anode permeate liquid tank 16.

The microorganism growth substrate comprises KH₂PO₄ 3-5g/L、K₂HPO₄·3H₂O2-4 g/L and glucose 0.8-1.0g/L, MgCl₂·6H₂O 0.08-0.24g/L、CaCl₂·2H₂O 0.08-0.24g/L、(NH₄)₂SO₄ 0.25-0.35g/L、MgSO₄0.02-0.04g/L、MnSO₄·H₂O 3-6mg/L、NaCl 8-16mg/L、FeSO₄·7H₂O 0.8-1.6mg/L、CoCl₂·6H₂O 0.8-1.6mg/L、ZnCl₂ 1-2mg/L、CuSO₄·5H₂O 0.1-0.2mg/L、AlK(SO₄)₂·7H₂O 0.1-0.2mg/L、H₃BO₃ 0.1-0.2mg/L、Na₂MoO₄ 0.5-1mg/L、NiCl₂·6H₂O0.3-0.6mg/L and Na₂WO₄·2H₂O 0.3-0.6mg/L。

Compared with the existing reactor, the reactor of the invention has the following advantages: firstly, at the cathode, the azo bond of the azo dye is broken through the action of anaerobic electrochemical active microorganism and electrochemistry, so that the azo dye is degraded into intermediate products such as aromatic amine and the like, and the intermediate products are further anodized by an electrocatalytic membrane H₂The active groups such as hydroxyl free radical generated by O are oxidized and converted into CO₂And H₂O, the azo dye has high removal efficiency. Secondly, the anode is based on the advanced oxidation principle, and the problem that intermediate products such as aromatic amine and the like in the anaerobic stage poison aerobic microorganisms in the existing anaerobic-aerobic process is solved.

Drawings

FIG. 1 is a schematic diagram of an anaerobic biocathode-electrocatalytic membrane reactor for treating azo wastewater.

Detailed Description

The invention will be further described with reference to specific embodiments and the accompanying drawings.

The azo dye wastewater to be treated refers to azo dye wastewater with the conductivity of more than 7 mS/cm.

MnO_xPreparation of a Ti porous electrocatalytic membrane:

placing a microporous titanium membrane (commodity) in an oxalic acid water solution with the mass fraction of 50% for ultrasonic treatment for 30min, taking out the microporous titanium membrane and washing the microporous titanium membrane to be neutral by deionized water, and airing the microporous titanium membrane at room temperature; then soaking in Mn (NO) with a mass fraction of 50%₃)₂Performing ultrasonic treatment in water solution for 30min, smoothly pulling out, and air drying at room temperature; and finally, placing the mixture in a muffle furnace for sintering: heating from room temperature to 120 ℃ at a heating rate of 0.5 ℃/min, then heating to 350 ℃/min at a heating rate of 5 ℃/min, preserving heat for 2h, and naturally cooling in a furnace to obtain load MnO_xTitanium-based electrocatalytic membranes, i.e. MnO_xA Ti porous electrocatalytic membrane.

A microporous titanium membrane (pore diameter of 7 μm, porosity of 22.3%, manufacturer: Saian Si Yu metallic materials Co., Ltd.).

TiO₂Preparation of a Ti porous electrocatalytic membrane:

placing a microporous titanium membrane (commodity) in a nitric acid water solution with the mass fraction of 65% for ultrasonic treatment for 30min, taking out the microporous titanium membrane, washing the microporous titanium membrane to be neutral by deionized water, and airing the microporous titanium membrane at room temperature; then soaking in TiO₂Performing ultrasonic treatment in the sol for 30min, and stably pulling out and drying at room temperature; and finally, placing the mixture in a muffle furnace for sintering: heating from room temperature to 120 ℃ at a heating rate of 0.5 ℃/min, then heating to 350 ℃/min at a heating rate of 5 ℃/min, preserving heat for 1h, and naturally cooling in a furnace to obtain the loaded TiO₂Of titanium-based electrocatalytic carbon films, i.e. TiO₂A Ti porous electrocatalytic membrane.

TiO₂Sol: mixing 34mL of butyl titanate and 136mL of absolute ethyl alcohol, and stirring to form a solution A; mixing 34mL of deionized water and 34mL of absolute ethyl alcohol, and dropwise adding about 6.8mL of nitric acid to keep the pH value at 3 to form a solution B; solution A was added dropwise to solution B at room temperature and fed through a constant temperature magnetic stirrerStirring to obtain TiO₂And (3) sol.

A microporous titanium membrane (pore diameter of 7 μm, porosity of 22.3%, manufacturer: Saian Si Yu metallic materials Co., Ltd.).

Example 1

An anaerobic biological cathode-electrocatalysis membrane series reactor (shown in figure 1) for azo wastewater treatment comprises an electrolytic cell 17 and is characterized in that a cation exchange membrane 6 is arranged in the electrolytic cell 17 to divide the electrolytic cell 17 into an anode chamber 7 and a cathode chamber 2, an electrocatalysis membrane 3 is arranged in the anode chamber 7 to divide the anode chamber 7 into an anode water inlet cavity 4 and an anode water outlet cavity 5, a filler 1 and a carbon rod 9 are arranged in the cathode chamber 2, and an adjustable direct current stabilized voltage power supply 8 is respectively connected with the electrocatalysis membrane 3 and the carbon rod 9 through leads; the cathode feed liquid tank 10 is sequentially connected with a first peristaltic pump 14 and the bottom of the cathode chamber 2 through pipelines, the pipeline connected with the top of the cathode chamber 2 is divided into three branches, the first branch is sequentially connected with a first valve 12 and the cathode feed liquid tank 10 through pipelines, the second branch is connected with a cathode water outlet tank 11 through a second valve 13, and the third branch is connected with the bottom of the cathode chamber 2 through a third peristaltic pump 18; the cathode water outlet groove 11 is connected with the bottom of the anode water inlet cavity 4 through a second peristaltic pump 15, and the anode permeation groove 16 is connected with the top of the anode water outlet cavity 5 through a pipeline.

The cation exchange membrane is polyethylene cation exchange membrane, and can also be polyphenylene oxide cation exchange membrane or vinylidene fluoride cation exchange membrane.

The electrocatalytic film is MnO_xA porous Ti electrocatalytic film, optionally TiO₂A Ti porous electrocatalytic membrane.

The filler is graphite felt, and can also be active carbon or semi-coke.

Example 2

The azo wastewater treatment method comprises the following steps:

1) the reactor of example 1 was used;

the electrolytic cell 22 has a size of 8cm × 8cm × 16cm (length × 0 width × 1 height), the cathode chamber has a size of 4cm × 8cm × 16cm (length × width × height), the lower part is provided with a water distribution plate, the upper part adopts graphite felt as cathode filler, the anode chamber has a size of 4cm × 8cm × 16cm (length × width × height), and an electro-catalytic membrane (MnO)_xA Ti porous electro-catalytic membrane) and a cation exchange membrane (polyethylene cation exchange membrane) are separated by 1 cm;

2) injecting 150mg/L alizarin yellow aqueous solution (the conductivity is 8mS/cm) into a cathode water outlet tank 11, and injecting 150mg/L alizarin yellow aqueous solution (the conductivity is 8mS/cm, and a microorganism growth substrate is added) into a cathode material liquid tank 10;

3) opening a first peristaltic pump 14, a second peristaltic pump 15 and a first valve 12 to enable liquid in the cathode feed liquid tank 10 to circulate between the cathode chamber and the cathode feed liquid tank 10, pumping the liquid in the cathode water outlet tank 11 into the anode water inlet cavity 4, treating the liquid by the electro-catalytic membrane 3, then enabling the liquid to enter the anode water outlet cavity 5, and discharging the liquid into the anode permeation tank 16 through a pipeline;

4) the adjustable DC stabilized power supply 8 is opened, and the control voltage is 0.8V;

5) sludge is obtained from a municipal sewage treatment plant, the sludge and 150mg/L alizarin yellow aqueous solution (in which a microorganism growth matrix is added) are mixed according to the volume ratio of 1: 1 to obtain inoculation liquid, the liquid in a cathode liquid tank 10 is replaced, and the cathode of a reactor is inoculated; changing the inoculation liquid every 7 days, and completing inoculation when the decolorizing efficiency of cathode alizarin yellow is increased and tends to be stable (the example is stable at 69%);

6) closing the first valve 12, opening the second valve 13 and the third peristaltic pump 18, injecting 150mg/L alizarin yellow aqueous solution (with the conductivity of 8mS/cm, wherein a microorganism growth substrate is added) into the cathode feed liquid tank 10, allowing the alizarin yellow aqueous solution to enter the cathode chamber 2 through the first peristaltic pump 14 for treatment, discharging treated cathode effluent from the top of the cathode chamber, returning a part of cathode effluent to the cathode chamber 2 through the third peristaltic pump 18 for internal circulation, allowing the other part of cathode effluent to flow into the cathode effluent tank 11 through the second valve 13, allowing the cathode effluent in the cathode effluent tank 11 to flow into the anode water inlet cavity 4 through the second peristaltic pump 15 for treatment, and discharging the cathode effluent from the anode effluent cavity into the anode permeate liquid tank 16 through the electro-catalytic membrane 3.

The microorganism growth substrate comprises KH₂PO₄ 3g/L、K₂HPO₄·3H₂O2 g/L and glucose 0.8g/L, MgCl₂·6H₂O 0.08g/L、CaCl₂·2H₂O 0.08g/L、(NH₄)₂SO₄ 0.25g/L、MgSO₄ 0.02g/L、MnSO₄·H₂O 3mg/L、NaCl 8mg/L、FeSO₄·7H₂O 0.8mg/L、CoCl₂·6H₂O 0.8mg/L、ZnCl₂ 1mg/L、CuSO₄·5H₂O 0.1mg/L、AlK(SO₄)₂·7H₂O 0.1mg/L、H₃BO₃ 0.1mg/L、Na₂MoO₄ 0.5mg/L、NiCl₂·6H₂O0.3 mg/L and Na₂WO₄·2H₂O 0.3mg/L。

The treatment effect is as follows: the decolorizing efficiency of alizarin yellow is 82%, and the COD removal rate is 65%.

Example 3

The azo wastewater treatment method comprises the following steps:

1) the reactor of example 1 was used;

the electrolytic cell 22 has a size of 8cm × 8cm × 16cm (length × 0 width × 1 height), the cathode chamber has a size of 4cm × 8cm × 16cm (length × width × height), the lower part is provided with a water distribution plate, the upper part adopts activated carbon as cathode filler, the anode chamber has a size of 4cm × 8cm × 16cm (length × width × height), and an electro-catalytic membrane (MnO)_xA Ti porous electro-catalytic membrane) and a cation exchange membrane (wherein the cation exchange membrane is a polyphenyl ether cation exchange membrane) are separated by 1 cm;

2) injecting 200mg/L alizarin yellow aqueous solution (the conductivity is 8mS/cm) into a cathode water outlet tank 11, and injecting 200mg/L alizarin yellow aqueous solution (the conductivity is 8mS/cm, and a microorganism growth substrate is added) into a cathode material liquid tank 10;

3) opening a first peristaltic pump 14, a second peristaltic pump 15 and a first valve 12 to enable liquid in the cathode feed liquid tank 10 to circulate between the cathode chamber and the cathode feed liquid tank 10, pumping the liquid in the cathode water outlet tank 11 into the anode water inlet cavity 4, treating the liquid by the electro-catalytic membrane 3, then enabling the liquid to enter the anode water outlet cavity 5, and discharging the liquid into the anode permeation tank 16 through a pipeline;

4) opening the adjustable direct current stabilized power supply (8), and controlling the voltage to be 1.3V;

5) taking sludge from a bioelectrochemical system, mixing the sludge with 200mg/L alizarin yellow aqueous solution (in which a microbial growth matrix is added) according to the volume ratio of 4: 5 to obtain inoculation liquid, replacing the feed liquid in a cathode feed liquid tank 10, and inoculating the cathode of the reactor; changing the inoculation liquid every 2 days, and completing inoculation when the decolorizing efficiency of cathode alizarin yellow is increased and tends to be stable (the example is stable at 77%);

6) closing the first valve 12, opening the second valve 13 and the third peristaltic pump 18, injecting 200mg/L alizarin yellow aqueous solution (with the conductivity of 8mS/cm, wherein a microorganism growth substrate is added) into the cathode feed liquid tank 10, allowing the alizarin yellow aqueous solution to enter the cathode chamber 2 through the first peristaltic pump 14 for treatment, discharging treated cathode effluent from the top of the cathode chamber, returning a part of cathode effluent to the cathode chamber 2 through the third peristaltic pump 18 for internal circulation, allowing the other part of cathode effluent to flow into the cathode effluent tank 11 through the second valve 13, allowing the cathode effluent in the cathode effluent tank 11 to flow into the anode water inlet cavity 4 through the second peristaltic pump 15 for treatment, and discharging the cathode effluent from the anode effluent cavity into the anode permeate liquid tank 16 through the electro-catalytic membrane 3.

The microorganism growth substrate comprises KH₂PO₄ 5g/L、K₂HPO₄·3H₂O4 g/L, glucose 1.0g/L, MgCl₂·6H₂O 0.24g/L、CaCl₂·2H₂O 0.24g/L、(NH₄)₂SO₄ 0.35g/L、MgSO₄ 0.04g/L、MnSO₄·H₂O 6mg/L、NaCl 16mg/L、FeSO₄·7H₂O 1.6mg/L、CoCl₂·6H₂O 1.6mg/L、ZnCl₂ 2mg/L、CuSO₄·5H₂O 0.2mg/L、AlK(SO₄)₂·7H₂O 0.2mg/L、H₃BO₃ 0.2mg/L、Na₂MoO₄ 1mg/L、NiCl₂·6H₂O0.6 mg/L and Na₂WO₄·2H₂O 0.6mg/L。

The treatment effect is as follows: alizarin yellow decolorization efficiency is 93%, and COD removal rate is 75.4%.

Experiments prove that the TiO is used₂the/Ti porous electrocatalytic membrane replaces MnO of the example_xthe/Ti porous electrocatalytic membrane, otherwise similar to this example, decolorization efficiency and COD removal rate were similar to this example.

Example 4

The azo wastewater treatment method comprises the following steps:

1) the reactor of example 1 was used;

the size of the electrolytic cell 22 is 8cm × 8cm × 16cm (length × 0 width × 1 height), the size of the electrolytic cell 22 is 8cm × 28cm × 316cm (length × 4 width × 5 height), the size of the cathode chamber is 4cm × 8cm × 16cm (length × width × height), the lower part of the electrolytic cell is provided with a water distribution plate, the upper part of the electrolytic cell adopts semicoke as a cathode filler, the size of the anode chamber is 4cm × 8cm × 16cm (length × width × height), and an electro-catalytic membrane (MnO) is arranged in the anode chamber_xa/Ti porous electro-catalytic membrane) and a cation exchange membrane (wherein the cation exchange membrane is a vinylidene fluoride cation exchange membrane) are separated by 1 cm;

2) injecting 200mg/L of acid orange AO7 aqueous solution (the conductivity is 8mS/cm) into a cathode water outlet tank 11, and injecting 200mg/L of acid orange AO7 aqueous solution (the conductivity is 8mS/cm, wherein a microorganism growth substrate is added) into a cathode feed tank 10;

3) opening a first peristaltic pump 14, a second peristaltic pump 15 and a first valve 12 to enable liquid in the cathode liquid tank 10 to circulate between the cathode chamber 2 and the cathode liquid tank 10, pumping liquid in the cathode water outlet tank 11 into the anode water inlet cavity 4, treating the liquid by the electro-catalytic membrane 3, then enabling the liquid to enter the anode water outlet cavity 5, and discharging the liquid into the anode permeation tank 16 through a pipeline;

4) the adjustable DC stabilized power supply 8 is turned on, and the control voltage is 5 mA;

5) sludge is obtained from a municipal sewage treatment plant, the sludge and 200mg/L of acid orange AO7 aqueous solution (wherein a microorganism growth matrix is added) are mixed according to the volume ratio of 1: 1 to obtain inoculation liquid, the feed liquid in a cathode feed liquid tank 10 is replaced, and the cathode of a reactor is inoculated; the inoculation liquid is replaced every 4 days, and when the decolorization efficiency of the cathode acid orange AO7 is increased and tends to be stable (the example is stable at 80 percent), the inoculation is completed;

6) closing the first valve 12, opening the second valve 13 and the third peristaltic pump 18, injecting 200mg/L acid orange AO7 aqueous solution (with the conductivity of 8mS/cm, wherein the microorganism growth substrate is added) into the cathode feed liquid tank 10, allowing the acid orange AO7 aqueous solution to enter the cathode chamber 2 for treatment through the first peristaltic pump 14, discharging the treated cathode effluent from the top of the cathode chamber, returning a part of the cathode effluent to the cathode chamber 2 for internal circulation through the third peristaltic pump 18, allowing the other part of the cathode effluent to flow into the cathode effluent tank 11 through the second valve 13, allowing the cathode effluent in the cathode effluent tank 11 to flow into the anode water inlet chamber 4 for treatment through the second peristaltic pump 15, and finally discharging the cathode effluent from the anode effluent chamber into the anode permeate liquid tank 16.

The microorganism growth substrate comprises KH₂PO₄ 4.4g/L、K₂HPO₄·3H₂O3.4 g/L, glucose 1.0g/L, MgCl₂·6H₂O 0.08g/L、CaCl₂·2H₂O 0.08g/L、(NH₄)₂SO₄ 0.25g/L、MgSO₄ 0.02g/L、MnSO₄·H₂O 3mg/L、NaCl 8mg/L、FeSO₄·7H₂O 0.8mg/L、CoCl₂·6H₂O 0.8mg/L、ZnCl₂ 1mg/L、CuSO₄·5H₂O 0.1mg/L、AlK(SO₄)₂·7H₂O 0.1mg/L、H₃BO₃ 0.1mg/L、Na₂MoO₄ 0.5mg/L、NiCl₂·6H₂O0.3 mg/L and Na₂WO₄·2H₂O 0.3mg/L。

The treatment effect is as follows: acid orange AO7 decolorization efficiency is 93%, and COD clearance is 76%.

Experiments prove that the TiO is used₂the/Ti porous electrocatalytic membrane replaces MnO of the example_xthe/Ti porous electrocatalytic membrane, otherwise similar to this example, decolorization efficiency and COD removal rate were similar to this example.

Example 5

The azo wastewater treatment method comprises the following steps:

1) the reactor of example 1 was used;

the electrolytic cell 22 has a size of 8cm × 8cm × 16cm (length × 0 width × 1 height), the cathode chamber has a size of 4cm × 8cm × 16cm (length × width × height), the lower part is provided with a water distribution plate, the upper part adopts graphite felt as cathode filler, the anode chamber has a size of 4cm × 8cm × 16cm (length × width × height), and an electro-catalytic membrane (MnO)_xa/Ti porous electro-catalytic membrane) and a cation exchange membrane (wherein the cation exchange membrane is a vinylidene fluoride cation exchange membrane) are separated by 1 cm;

2) injecting 150mg/L of acid orange AO7 aqueous solution (the conductivity is 8mS/cm) into a cathode water outlet tank 11, and injecting 150mg/L of acid orange AO7 aqueous solution (the conductivity is 8mS/cm, wherein a microorganism growth substrate is added) into a cathode feed tank 10;

3) opening a first peristaltic pump 14, a second peristaltic pump 15 and a first valve 12 to enable liquid in the cathode liquid tank 10 to circulate between the cathode chamber 2 and the cathode liquid tank 10, pumping liquid in the cathode water outlet tank 11 into the anode water inlet cavity 4, treating the liquid by the electro-catalytic membrane 3, then enabling the liquid to enter the anode water outlet cavity 5, and discharging the liquid into the anode permeation tank 16 through a pipeline;

4) the adjustable DC stabilized power supply 8 is turned on, and the control voltage is 2 mA;

5) taking sludge from a bioelectrochemical system, mixing the sludge with 150mg/L of acid orange AO7 aqueous solution (wherein a microorganism growth matrix is added) according to the volume ratio of 4: 5 to obtain inoculation liquid, replacing the feed liquid in a cathode feed liquid tank 10, and inoculating the cathode of the reactor; the inoculation liquid is changed every 3 days, and when the decolorization efficiency of the cathode acid orange AO7 is increased and tends to be stable (the example is stable at 71.8 percent), the inoculation is completed;

6) closing the first valve 12, opening the second valve 13 and the third peristaltic pump 18, injecting 150mg/L acid orange AO7 aqueous solution (with the conductivity of 8mS/cm, wherein the microorganism growth substrate is added) into the cathode feed liquid tank 10, allowing the acid orange AO7 aqueous solution to enter the cathode chamber 2 for treatment through the first peristaltic pump 14, discharging the treated cathode effluent from the top of the cathode chamber, returning a part of the cathode effluent to the cathode chamber 2 for internal circulation through the third peristaltic pump 18, allowing the other part of the cathode effluent to flow into the cathode effluent tank 11 through the second valve 13, allowing the cathode effluent in the cathode effluent tank 11 to flow into the anode water inlet chamber 4 for treatment through the second peristaltic pump 15, and finally discharging the cathode effluent from the anode effluent tank 16 into the anode permeate liquid tank.

The microorganism growth substrate comprises KH₂PO₄ 4.4g/L、K₂HPO₄·3H₂O3.4 g/L, glucose 1.0g/L, MgCl₂·6H₂O 0.08g/L、CaCl₂·2H₂O 0.08g/L、(NH₄)₂SO₄ 0.25g/L、MgSO₄ 0.02g/L、MnSO₄·H₂O 3mg/L、NaCl 8mg/L、FeSO₄·7H₂O 0.8mg/L、CoCl₂·6H₂O 0.8mg/L、ZnCl₂ 1mg/L、CuSO₄·5H₂O 0.1mg/L、AlK(SO₄)₂·7H₂O 0.1mg/L、H₃BO₃ 0.1mg/L、Na₂MoO₄ 0.5mg/L、NiCl₂·6H₂O0.3 mg/L and Na₂WO₄·2H₂O 0.3mg/L。

The treatment effect is as follows: the decolorization efficiency of the acid orange AO7 is 85.2%, and the COD removal rate is 69.3%.

Experiments prove that the TiO is used₂the/Ti porous electrocatalytic membrane replaces MnO of the example_xthe/Ti porous electrocatalytic membrane, otherwise similar to this example, decolorization efficiency and COD removal rate were similar to this example.