CN101967017B - An electrochemical device for wastewater treatment and a method for treating wastewater using the device - Google Patents

Abstract

The invention relates to an electrochemical device for wastewater treatment and a method for treating wastewater by using the same. The electrochemical device consists of a power supply, a primary electrolytic bath B, an electrolytic bath A, an electrolytic bath C, a cathode, a permeable isolation material part, an anode, a raw water tank, a purified water collector and a concentrated solution collecting tank. The electrochemical device can simultaneously remove common negative ions such as nitrate radicals, phosphate radicals, chloride ions, fluorine ions and the like and organic substances, does not need to add any agent, can avoid second pollution to the effluent, is convenient to operate, and has high treatment efficiency and low energy consumption.

Description

An electrochemical device for wastewater treatment and a method for treating wastewater using the device

【Technical field】

The invention belongs to the technical field of wastewater treatment. More specifically, the present invention relates to an electrochemical device for wastewater treatment, and also to a method of treating wastewater using the device. the

【Background technique】

At present, the effluent water quality indicators obtained by the conventional treatment of sewage treatment plants have reached the harmless discharge standards such as total nitrogen <35ppm, COD <50ppm, total phosphorus <10ppm, and suspended solids <30ppm. There is still a big gap in resource utilization such as irrigation and river and lake replenishment. The main reason is firstly that the content of total nitrogen and total phosphorus is still high, leading to prominent eutrophication of water quality, prone to a series of problems such as blooms and odors; secondly, common anions such as fluorine, chlorine and bromine in water are difficult to remove . In order to meet the resource requirements of sewage treatment effluent, it is necessary to develop deep water purification technology to reduce the content of nitrogen and phosphorus in water to below the discharge standard limit, and to significantly reduce the content of anions such as fluorine and chlorine. However, the existing conventional sewage treatment technologies such as flocculation, sedimentation, and biochemical treatment are difficult to reduce the low concentration of nitrate, phosphate, chloride, fluoride, and organic matter in the water to meet the requirements of effluent resources. the

For the removal of nitrogen, phosphorus and organic matter in sewage, the widely used treatment technologies are biological method and chemical precipitation method; for anions such as fluorine and chlorine in water, the common and effective method is to dilute with water. However, these technologies have many disadvantages in practical application, such as long residence time of water flow, large floor area, large amount of sludge that is difficult to dispose of, poor stability of biological treatment process, and conventional denitrification process needs to add carbon source or Chemical agents, high cost, complicated operation and cumbersome management. the

A method for deep removal of nitrate radicals in sewage is to directly perform electrochemical reduction degradation under the action of an electric field. the

For example, Chinese patent CN200410098590.2, "Metal Modified Activated Carbon Fiber Electrode and Method for Removing Nitrate Using the Electrode" discloses the use of precious metals such as palladium, platinum and gold, and copper, tin, copper and zinc, etc. One of the non-precious metals is carried on the modified activated carbon fiber to make an active cathode electrode that can reduce nitrate in water, and use graphite, lead dioxide and other inert conductive materials as the anode, and the cathode and anode are separated by a proton exchange membrane. , in the case of electricity, the reduction of nitrate. In this invention, the cathode is the place where the nitrate catalytic reduction reaction takes place. Since the cathode is negatively charged, it will produce an electric repulsion effect with the same negatively charged nitrate ions, so that the nitrate is attached to the surface of the cathode catalyst, and then it is connected with the cathode. The chance of catalytic reduction reaction of H2 produced by electrolysis is relatively limited, so the reaction efficiency and the effect of removing nitrate are difficult to improve. the

Regarding electrocoagulation to remove phosphate, fluoride ions and organic matter in sewage, Chinese patent CN1986435A proposes a combined process of electrocoagulation and microfiltration, that is, using aluminum or iron plates as electrodes to electrolyze aluminum or iron salts, combined with fluoride ions in water Larger flocs are formed with organic matter, and then the formed flocs are filtered and removed in the subsequent microfiltration membrane module, so as to achieve the purpose of removing fluorine and organic matter from drinking water. This process needs to be combined with a microfiltration device to increase the processing cost, the surface of the electrode is easy to form an oxide film and passivate, the types of pollutants that can be treated are single, the concentration of the target substance in the water body is small, and the electrochemical efficiency is low. Chinese patent CN 101269863A proposes to utilize the combined process of electrocoagulation and membrane bioreactor, adopt iron plate or aluminum plate as anode electrolysis to produce iron ion or aluminum ion, form floc with hydroxide ion, phosphate ion in sewage, organic matter has The microorganisms in the membrane bioreactor degrade to form sludge, and the pollutants are removed by microfiltration membrane, so as to achieve the purpose of removing phosphorus and organic matter from sewage. The electrochemical efficiency of this system is low, the treatment cost is high, and a large amount of sludge that is difficult to dispose is produced. The stability of biological treatment is poor, and the types of pollutants to be treated are single. the

Chinese patent CN02146020.5 "Activated carbon fiber and electrokinetic synergistic purification method and device for drinking water" discloses a method and device for activated carbon fiber and electrokinetic synergistic purification of drinking water, that is, an electric field is applied to the activated carbon fiber filter material, and the In the presence of electric current, the movement of harmful ions and bacteria is no longer solely determined by the flow field, but by the joint action of the electric field and the flow field. Electrokinetic effects such as electromigration and electrophoresis under the action of the electric field can effectively increase the concentration of pollutant ions in water. , particles, and the collision frequency of bacteria and activated carbon fibers, thereby improving the adsorption rate and adsorption effect. However, the disadvantage of this device is that the electrodes need to be regenerated periodically, the operation process is complicated and cumbersome, and the processing cost is high. the

The electrodialysis or reverse osmosis technology used in the drinking water system is not suitable for the advanced treatment of sewage due to its low efficiency and the use of expensive ion exchange membranes. the

【Content of invention】

[Technical problem to be solved]

The object of the present invention is to provide an electrochemical device for wastewater treatment. the

Another object of the present invention is to provide a method for treating wastewater containing anions and organic matter using the electrochemical device. the

[Technical solutions]

The present invention is achieved through the following technical solutions. the

The invention relates to an electrochemical device for wastewater treatment. the

What shown in accompanying drawing 1 is the most basic electrochemical device for waste water treatment, and this device is made up of power supply 1, primary electrolyzer B, electrolyzer A, electrolyzer C, negative electrode 5, permeable isolation material part 6, anode 7 , raw water pool 2, clean water collector 3 and concentrated solution collection pool 4 are composed of, each of the electrolyzers includes a cell body, an anode, a cathode and a permeable isolation material part; the permeable isolation material part is A component that separates the tank body into an anode area and a cathode area;

The water to be treated in the raw water pool 2 enters from the bottom of the cathode area of the primary electrolytic cell B, and then flows out from the top of the cathode area and the anode area respectively;

The water body flowing out from the primary electrolytic cell B anode area enters from the bottom of the cathode area of the electrolytic cell A, and then flows out from the top of its anode area and cathode area respectively, and the water body flowing out from the top of its anode area enters the concentrated solution collection pool 4, and from The water flowing from the top of the cathode area enters the raw water pool 2;

The water body flowing out from the cathode area of the primary electrolytic cell B enters from the bottom of the cathode area of the electrolytic cell C, and then flows out from the top of its anode area and cathode area respectively; the water body flowing out from the top of its cathode area enters the water purification collector 3, and from The water body flowing out from the top of the anode area enters the raw water pool 2 . the

According to a preferred embodiment of the present invention, the described electrochemical device for wastewater treatment (see accompanying drawing 2) consists of a power supply 1, a primary electrolyzer B, an electrolyzer A1, an electrolyzer A2, an electrolyzer C1, an electrolyzer C2, cathode 5, permeable isolation material part 6, anode 7, raw water pool 2, water purification collector 3 and concentrated solution collection pool 4, each electrolytic cell includes a cell body, an anode, a cathode and a permeable Sexual isolation material part; The described permeable isolation material part is a component that separates the tank body into an anode area and a cathode area;

The water to be treated in the raw water pool 2 enters from the bottom of the cathode area of the primary electrolytic cell B, and then flows out from the top of the cathode area and the anode area respectively;

The water flowing out from the anode area of the primary electrolytic cell B enters from the bottom of the cathode area of the electrolytic cell A1, and then flows out from the top of the anode area and the cathode area respectively; the water flowing out from the top of the anode area of the electrolytic cell A1 enters the cathode area of the electrolytic cell A2 The bottom flows out from the top of its anode area and cathode area then; the water body flowing out from the top of the electrolyzer A2 cathode area enters the bottom of the electrolyzer A1 cathode area; the water body flowing out from the top of the electrolyzer A2 anode area enters the concentrated solution collection pool 4, and The nitrate concentration of the water body in the concentrated solution collection pool 4 can reach a higher concentration suitable for biochemical treatment, or a higher concentration of higher electrolysis current efficiency; while the water flowing out from the top of the cathode area of the electrolytic cell A1 still returns to the raw water pool 2 , for cyclic electrolysis;

The water flowing out from the cathode area of primary electrolytic cell B enters from the bottom of the cathode area of electrolytic cell C1, and then flows out from the top of its anode area and cathode area respectively;

The water body flowing out from the top of the cathode area of electrolytic cell C1 enters the bottom of the cathode area of electrolytic cell C2, and then flows out from the top of its anode area and cathode area; the water body flowing out from the top of the cathode area of electrolytic cell C2 enters the water purification collector 3, and the The water quality in the water collector 3 can reach the requirement of reutilization; The water body flowing out from the top of the electrolytic cell C2 anode area flows into the bottom of the electrolytic cell C1 cathode area again; Return to the original water pool 2 for cyclic electrolysis. the

According to another preferred embodiment of the present invention, the tank body is a plastic container, an iron container that has undergone corrosion-resistant and insulating treatment, or other corrosion-resistant and insulating containers. the

According to another preferred embodiment of the present invention, the anode is composed of a soluble anode or an insoluble anode, or

The anode is composed of a soluble anode and an insoluble anode connected in parallel. the

According to another preferred embodiment of the present invention, the cathode is composed of metal or non-metal electrodes. the

According to another preferred embodiment of the present invention, the soluble anode is a mesh, strip, plate or block electrode made of iron, aluminum and alloys thereof; the insoluble anode is made of platinum, Mesh, strip, plate or block electrodes made of iridium, ruthenium, palladium, titanium/ruthenium dioxide or titanium/iridium dioxide. the

According to another preferred embodiment of the present invention, the cathode is a mesh, strip, plate or block electrode made of palladium, copper, nickel, iron or aluminum and their alloys or graphite nonmetal. the

The present invention also relates to a method for treating wastewater containing anions and organic matter, which is characterized in that the electrochemical device is used to treat the wastewater, a DC electric field is applied between the anode and the cathode, and the primary The current density of electrolytic cell B is controlled at 0.5-50mA/cm ² , the current density of electrolytic cell A is controlled at 2.5-100mA/cm ² ; the current density of electrolytic cell C is controlled at 0.1-30mA/cm ² .

According to a preferred embodiment of the present invention, a direct current electric field is applied between the anode and the cathode, the current density of the primary electrolytic cell B is controlled at 5-30mA/cm ² , and the electrolytic cell A The current density is controlled at 30-80mA/cm ² , and when multiple electrolytic cells A are used in combination, the current density of the adjacent electrolytic cell A below is greater than the current density of the adjacent electrolytic cell A in front; the electrolytic cell C The current density is controlled at 0.5-20mA/cm ² , and when multiple electrolytic cells are used in combination, the current density of the lower adjacent electrolytic cell C is lower than that of the front adjacent electrolytic cell C.

The present invention will be described in more detail below. the

The invention relates to an electrochemical device for wastewater treatment. the

The electrochemical device of the present invention simultaneously realizes the joint action of electromigration, electrocoagulation and electrochemical degradation in the device, and simultaneously removes common anions and organic substances such as nitrate, phosphate, chloride, and fluoride in water. Chemical devices can improve degradation efficiency, reduce energy consumption and reduce processing time. the

The device (accompanying drawing 1) is composed of power supply 1, primary electrolyzer B, electrolyzer A, electrolyzer C, cathode 5, permeable isolation material part 6, anode 7, raw water pool 2, water purification collector 3 and concentrated solution The collection pool consists of 4. the

The power supply 1 is a direct current power supply, and its voltage requirement is 0-36 volts, and the current is 0-1000 amps. The DC power supply device is, for example, a DC power supply produced by Shanghai Wenbo Electric Co., Ltd. Its input voltage is single-phase AC220V±10%, three-phase 380V, output voltage, 0 to the maximum adjustable value; output current, 0 to Maximum adjustable value, frequency, 50Hz/60Hz. the

According to the present invention, each electrolytic cell includes a cell body, an anode, a cathode and a portion of a permeable insulating material. the

In the present invention, the tank body is a plastic container, a corrosion-resistant and insulating iron container or other corrosion-resistant insulating containers. the

For example, the plastic container is a phenolic resin container, a furan resin container or a fiberglass container. The iron container is a steel container with epoxy resin, furan resin, polyester resin, phenolic resin or rubber anti-corrosion lining inside the steel tank. The corrosion-resistant insulating container is a corrosion-resistant insulating container made of cement or ceramic material. Some of these electrolytic containers can be purchased directly from the market, and some can be processed or customized according to specific size requirements. the

In the present invention, the anode is composed of soluble anode or insoluble anode. the

The anode can also be composed of a soluble anode and an insoluble anode connected in parallel. the

According to the present invention, the soluble anode is a mesh, strip, plate or block electrode made of iron, carbon steel, aluminum and alloys thereof. the

The insoluble anode is a mesh, strip, plate or block electrode made of platinum, iridium, ruthenium, palladium, titanium/ruthenium dioxide or titanium/iridium dioxide. Among them, the titanium/ruthenium dioxide electrode is an electrode composed of a titanium substrate and a ruthenium dioxide coating. This alloy is an alloy product currently sold on the market. Products sold with anodes. Titanium/iridium dioxide electrode is an electrode composed of titanium substrate and iridium dioxide coating. This alloy is an alloy product currently sold in the market. Products on sale. the

According to the present invention, the cathode is composed of metal or non-metal electrodes. the

Said metals are, for example, nickel, iron, aluminum and its alloys, copper and its alloys. The copper-based alloy is, for example, an alloy composed of 64.5%-66.5% copper, 16.5%-18.5% nickel, and the balance being zinc. This alloy is an alloy product currently sold on the market, such as Dongguan Yimei Metal Materials Ltd under the trade name C7521. The non-metal is, for example, graphite. the

The cathode is in the form of mesh, strip, plate or block. the

The permeable isolation material part is a component that separates the tank body into an anode area and a cathode area. the

According to the present invention, the permeable insulating material is, for example, a fabric-like insulating material. The part of the permeable isolation material is mainly used to limit the mixed flow of the catholyte and the anolyte, maintain the electrical conduction between the two, and allow the charged ions on both sides to migrate under the action of the electric field force. The permeable insulating material can be various dense cloth fabrics, such as various chemical fiber fabrics, such as polyester cloth or nylon cloth, various cotton cloths or filter cloths. The part of the permeable insulating material may be a cloth fabric layer, or a composite layer formed by stacking two or more cloth fabrics. the

In this composite layer, the intersecting angle of adjacent fabric warp yarns should be >45°. the

According to the present invention, in the electrolytic cell body, the anode, cathode and parts of the permeable isolation material should be well combined and matched in size. the

Applying a direct current electric field between the two poles of the electrolytic cell can realize electromigration, electrocoagulation and electrochemical degradation at the same time. Among them, common anions such as nitrate, phosphate, fluoride, and chloride ions are electrically migrated from the cathode area to the anode area through the isolation material part under the action of a direct current electric field, and the soluble anodes of iron, aluminum and their alloys are in the Fe ²⁺ and Al ³⁺ ions will be released under a DC electric field, which can form flocculent precipitates with larger molecular weights with phosphate ions and fluoride ions, which can be removed by sedimentation; in addition, nitrate can undergo electrochemical reduction near the cathode degraded and removed. Organic pollutants in water can be directly oxidized on the anode or oxidized by the oxidant produced by anode electrolysis, or converted into charged groups, which are removed by electromigration and flocculation in the electrolytic cell.

When using the electrochemical device of the present invention, the water body to be treated containing the anions and organic matter in the raw water pool 2 enters from the bottom of the cathode area of the primary electrolyzer B, and then flows from it according to the flow rate ratio of 3:1～5:1. Cathode zone and anode zone top outflow. A DC electric field is applied between the anode and the cathode, and the current density can be controlled in the range of 0.5-50mA/ ^cm2 according to the type and concentration of pollutants. The anions in the water to be treated undergo electromigration, electrocoagulation and electrochemical reduction simultaneously under the action of an electric field. Control the water flow rate so that the water body stays in the electrolytic cell for 1-5 minutes, and fully allow common anions such as nitrate, phosphate, and fluoride ions to penetrate the isolation material under the action of a DC electric field. Therefore, the water in the water flowing out from the anode area The concentration of nitrate ions is significantly higher than that of influent water, and phosphate ions and fluoride ions interact with iron and aluminum ions to form flocs and settle down; the concentration of anions in the effluent water in the cathode area is significantly lower than that of influent water.

The water flowing out from the anode area of the primary electrolytic cell B enters from the bottom of the cathode area of the electrolytic cell A, and then flows out from the top of the anode area and the cathode area respectively according to a certain flow rate ratio, and the water flowing out from the top of the anode area enters the concentrated solution collection pool 4. The anion concentration in the effluent water body in its anode area is further increased than that of the anode effluent of the previous electrolytic cell B. And the water body flowing out from the top of its cathode area enters the raw water pool 2, and the anion concentration in the water body flowing out from the cathode area is less than the anode water outlet of the previous electrolytic cell B. the

In order to improve degradation efficiency and reduce energy consumption, multiple electrolyzers can be used in combination. the

Adopt the combined electrochemical device of five electrolytic cells as shown in accompanying drawing 2, this device is made up of power supply 1, primary electrolytic cell B, electrolytic cell A1, electrolytic cell A2, electrolytic cell C1, electrolytic cell C2, negative electrode 5, transparent Transient isolation material part 6, anode 7, raw water pool 2, water purification collector 3 and concentrated solution collection pool 4. the

The water to be treated in the raw water pool 2 enters from the bottom of the cathode area of the primary electrolytic cell B, and then flows out from the top of the cathode area and the anode area respectively;

The water flowing out from the anode area of the primary electrolytic cell B enters from the bottom of the cathode area of the electrolytic cell A1, and then flows out from the top of the anode area and the cathode area respectively; the water flowing out from the top of the anode area of the electrolytic cell A1 enters the cathode area of the electrolytic cell A2 The bottom flows out from the top of its anode area and cathode area then; the water body flowing out from the top of the electrolytic cell A2 cathode area enters the bottom of the electrolytic cell Al cathode area; The nitrate concentration of the water body in the concentrated solution collection pool 4 can reach a higher concentration suitable for biochemical treatment, or a higher concentration of higher electrolysis current efficiency; while the water flowing out from the top of the cathode area of the electrolytic cell A1 still returns to the raw water pool 2 , for cyclic electrolysis;

The water flowing out from the cathode area of primary electrolytic cell B enters from the bottom of the cathode area of electrolytic cell C1, and then flows out from the top of its anode area and cathode area respectively;

The water body flowing out from the top of the cathode area of electrolytic cell C1 enters the bottom of the cathode area of electrolytic cell C2, and then flows out from the top of its anode area and cathode area; the water body flowing out from the top of the cathode area of electrolytic cell C2 enters the water purification collector 3, and the The water quality in the water collector 3 can reach the requirement of reutilization; The water body flowing out from the top of the electrolytic cell C2 anode area flows into the bottom of the electrolytic cell C1 cathode area again; Return to the original water pool for cyclic electrolysis. the

The present invention also relates to a method for treating wastewater containing anions and organic matter, which is characterized in that the electrochemical device is used to treat the wastewater, a DC electric field is applied between the anode and the cathode, and the primary The current density of electrolytic cell B is controlled at 0.5-50mA/cm ² , the current density of electrolytic cell A is controlled at 2.5-100mA/cm ² ; the current density of electrolytic cell C is controlled at 0.1-30mA/cm ² .

According to a preferred embodiment of the present invention, a direct current electric field is applied between the anode and the cathode, the current density of the primary electrolytic cell B is controlled at 5-30mA/cm ² , and the electrolytic cell A The current density is controlled at 30-80mA/cm ² , and when multiple electrolytic cells A (A, A1, and A2) are used in combination, the current density of the lower adjacent electrolytic cell A is greater than that of the front adjacent electrolytic cell A ; The current density of the electrolytic cell C (C, C1 and C2) is controlled at 0.5-20mA/cm ² , and when a plurality of electrolytic cells are used in combination, the current density of the adjacent electrolytic cell C below is lower than that of the previous adjacent The current density of electrolytic cell C.

The electrochemical device of the present invention can treat waste water containing common anions such as nitrate, nitrite, phosphate, sulfate, chloride, bromide, fluoride and organic matter. The waste water is, for example, urban domestic waste water and reclaimed water obtained after conventional treatment in sewage plants. the

When treating wastewater containing a large amount of solid waste, pretreatment is required to reduce solid waste or other suspended matter in the wastewater to a level that can be handled by the electrochemical device of the present invention, for example, solid waste should be controlled below 200mg/L. the

In addition, the pH value should be controlled at 6-8, and the viscosity of wastewater should be controlled below 1.2 centipoise at 25°C. the

The determination method of nitrate, phosphate, chloride ion, fluoride ion concentration and organic matter in the water body before and after treatment is compiled according to the editorial committee of the water and wastewater monitoring and analysis method of the State Environmental Protection Administration, "Water and Wastewater Monitoring and Analysis Method" (No. Fourth edition, supplementary edition), the determination method stipulated in China Environmental Science Press publication (2002) is analyzed and determined. the

A large number of tests have proved that the concentration of nitrate can be reduced from 40ppm to below 1ppm. Phosphate concentration can be reduced from 3ppm to below 0.1ppm. Chloride ion concentration can be reduced from 150ppm to below 20ppm. Fluoride ion concentration can be reduced from 2ppm to below 0.2ppm. The concentration of organic matter can be reduced from 300ppm to below 40ppm. the

[beneficial effect]

Compared with the prior art, the present invention has the following beneficial effects:

First, the present invention simultaneously realizes the joint action of electromigration, electrocoagulation and electrochemical degradation in one device by using an anode group and applying an electric field, and there are many types of pollutants that can be removed simultaneously, such as nitrate, phosphate, and chlorine in water Common anions and organic substances such as ions and fluoride ions;

Second, the use of woven fabric isolation materials in the present invention, compared with commonly used ion-exchange membranes, is cheap, and will not cause membrane pollution, and is easy to maintain;

Thirdly, the present invention utilizes electromigration, electrocoagulation and electrochemical degradation to jointly remove anions and organic matter in water without adding any chemicals, avoiding secondary pollution to effluent water, convenient operation, high treatment efficiency and low energy consumption. the

【Description of drawings】

Figure 1 is a schematic diagram of the electrochemical device of the present invention. the

1-power supply, 2-raw water pool, 3-clean water collector, 4-concentrated solution collection pool, primary electrolytic tank B, electrolytic tank A, electrolytic tank C, 5-cathode, 6-permeable isolation material part, 7 - anode, 8 - return pipe. the

Fig. 2 is a schematic diagram of a preferred electrochemical device of the present invention. the

1-power supply, 2-raw water pool, 3-clean water collector, 4-concentrated solution collection pool, primary electrolytic tank B, electrolytic tank A1, electrolytic tank C1, electrolytic tank A2, electrolytic tank C2, 5-cathode, 6- Permeable isolation material part, 7-anode, 8-return pipe

【Detailed ways】

The technical solutions of the present invention will be further described below in conjunction with the embodiments. the

Example 1

As shown in accompanying drawing 1, electrochemical device of the present invention is made up of power supply, primary electrolyzer B, electrolyzer A, electrolyzer C, negative electrode, permeable isolation material part, anode, raw water pool, clean water collector and concentrated solution collection pool composition. Each electrolytic cell includes a rectangular cell body made of phenolic resin, mesh-shaped (rhombic size, 12.5×4.5mm) Ti-IrO ₂ (substrate is Ti, coating is 20-50 μm thick IrO ₂ ) Anode, copper-based alloy plate (copper 64.5%-66.5%, nickel 16.5%-18.5%, the balance is zinc) cathode and permeable isolation material part thick 0.1mm nylon cloth. , the electrode area is 238cm ² (14cm×17cm), and the electrode spacing is 8mm. A DC power supply produced by Shanghai Wenbo Electric Co., Ltd. was used to apply a DC current between the anode and the cathode with a current density of 5 mA/cm ² .

The raw material solution is a self-prepared sodium nitrate aqueous solution with a nitrogen content of 20.2ppm, which flows in from the cathode area of the primary electrolytic cell B at a flow rate of 30ml/min. After 10min, the water body in the anode area is extracted at a flow rate of 5ml/min and injected into the electrolytic cell A. In the cathode area, the current density of electrolytic cell A is 8mA/cm ² ; the solution in the cathode area of primary electrolytic cell B is injected into the cathode area of electrolytic cell C at a flow rate of 25ml/min, and the current density of electrolytic cell C is 1.5mA/cm ² . After 20 minutes, the water body of each electrolytic cell reached a stable level, and the volume was basically the same. The nitrate concentration of the water body in the anode and cathode areas of each electrolytic cell was measured, and the test results are listed in Table 1.

Table 1: Nitrate concentration in the water body in the cathode and anode areas of each electrolyzer

As can be seen from the results in Table 1, using the electrochemical device of the present invention to process, within 20min about 1/3 of the volume of water (wherein the nitrate concentration is reduced to 1.9ppm) has reached the standard, while producing about 1/3 of the volume of Concentrated water (in which the concentration of nitrate is 140ppm), and about 1/3 of the remaining water circulates in the system. the

Example 2

In this example, nitrate in water was removed in the same manner as in Example 1, but the current density was changed. In this example, the current density of primary electrolytic cell B is 40mA/cm ² , the current density of electrolytic cell A is 80mA/cm ² , and the current density of electrolytic cell C is 20mA/cm ^{2 .} The concentration of nitrate in the water body of the area is shown in Table 2.

Table 2: Nitrate concentration in the water body in the cathode and anode areas of each electrolyzer

It can be seen that as the current density increases, the concentration of nitrate nitrogen can be reduced to below 1ppm, and the concentration in the anode area can be concentrated to 160ppm, but the high current density will lead to increased energy consumption. the

Example 3

As shown in Figure 2, five electrolyzers are used in combination, that is, a primary electrolyzer B, electrolyzers A1 and A2, and electrolyzers C1 and C2. the

The water flowing out from the anode area of the primary electrolytic cell B enters from the bottom of the cathode area of the electrolytic cell A1, and then flows out from the top of the anode area and the cathode area respectively; the water flowing out from the top of the cathode area of the electrolytic cell A1 returns to the raw water pool 2 for circulation Electrolysis; the water body flowing out from the top of the anode area of electrolytic cell A1 enters the bottom of the cathode area of electrolytic cell A2, and then flows out from the top of its anode area and cathode area; the water body flowing out from the top of the cathode area of electrolytic cell A2 enters the bottom of the cathode area of electrolytic cell A1; The water flowing out from the top of the anode area of the electrolytic cell A2 enters the concentrated solution collection pool 4 . the

The water flowing out from the cathode area of the primary electrolytic cell B enters from the bottom of the cathode area of the electrolytic cell C1, and then flows out from the top of the anode area and the cathode area respectively; the water flowing out from the top of the anode area of the electrolytic cell C1 returns to the raw water pool 2 for Circulating electrolysis; the water flowing out from the top of the cathode area of the electrolytic cell C1 enters the bottom of the cathode area of the electrolytic cell C2, and then flows out from the top of the anode area and the cathode area; the water flowing out from the top of the cathode area of the electrolytic cell C2 enters the water purification collector 3; The water body flowing out from the top of the anode area of the electrolytic cell C2 flows into the bottom of the cathode area of the electrolytic cell C1. the

The current density of primary electrolytic cell B is 10mA/cm ² , the current density of electrolytic cell A1 and A2 is 22mA/cm ² and 35mA/cm ² respectively, and the current density of electrolytic cell C1 and electrolytic cell C2 is 5mA/cm ² and 2 mA/cm ² .

Use mesh (diamond size, 12.5×4.5mm) Ti-IrO ₂ (substrate is Ti, coating is 20-50μm thick IrO ₂ ) and iron plate in parallel as anode group, copper-based alloy (copper 64.5%-66.5 %, nickel 16.5%-18.5%, the balance is zinc) as the cathode, the shape is plate. The electrode area is 0.63m ² (70cm×90cm), the electrode plate spacing is 6mm, and 0.1mm thick nylon cloth is used as the isolation layer. The flow rate is 10L/h.

The raw material solution is the effluent of the secondary settling tank of a certain sewage treatment plant, and the anion concentration of the effluent of the secondary settling tank is listed in Table 3. the

After being treated by the electrochemical device of the present invention, the concentration of anions in the effluent water was measured by the detection method described in this specification, and the analysis results are listed in Table 3. the

Table 3: Concentration of anions in the effluent water body treated by the electrochemical device of the present invention

As shown in the results of Table 3, after the effluent of the secondary sedimentation tank of the sewage treatment plant is treated by the electrochemical device of the present invention, three indicators of the effluent water quality of the cathode have all met the surface water class III standard, and the total phosphorus and fluorine ions in the anode effluent The concentration of nitrate has been reduced to a very low level and can be discharged directly without further treatment; nitrate has a relatively high concentration and can be treated biochemically. It can be seen that the deep water purification process described in the present invention has a significant removal effect on nitrogen, phosphorus, fluorine and chloride ions in sewage. the

Claims (9)

1. electrochemical appliance that is used for wastewater treatment; It is characterized in that this device is made up of with enriching soln collecting tank (4) power supply (1), primary electrolysis groove B, electrolyzer A, electrolyzer C, negative electrode (5), perviousness isolated material part (6), anode (7), former pond (2), water purification scoop (3), described each electrolyzer comprises cell body, anode, negative electrode and perviousness isolated material part; Described perviousness isolated material partly is a kind of parts that said cell body are separated into positive column and cathodic area;

Staying water in former pond (2) is got into by the bottom, cathodic area of primary electrolysis groove B, flows out from its top, cathodic area and top, positive column respectively again;

Effusive water body is got into by the bottom, cathodic area of electrolyzer A from primary electrolysis groove B positive column; Flow out from the top in its positive column and cathodic area respectively again; Effusive water body gets into enriching soln collecting tank (4) from its top, positive column, and returns former pond (2) from its effusive water body in top, cathodic area;

Effusive water body is got into by the bottom, cathodic area of electrolyzer C from primary electrolysis groove B cathodic area, flows out from the top in its positive column and cathodic area respectively again; Effusive water body gets into water purification scoop (3) from its top, cathodic area, and returns former pond (4) from its effusive water body in top, positive column.

2. electrochemical appliance that is used for wastewater treatment; It is characterized in that this device by power supply (1), primary electrolysis groove B, electrolyzer C1, electrolyzer C1 be connected in series at the back electrolyzer C2, electrolyzer A1, form with enriching soln collecting tank (4) at be connected in series at the back electrolyzer A2, negative electrode (5), perviousness isolated material part (6), anode (7), former pond (2), water purification scoop (3) of electrolyzer A1, described each electrolyzer comprises cell body, anode, negative electrode and perviousness isolated material part; Described perviousness isolated material partly is a kind of parts that said cell body are separated into positive column and cathodic area;

Staying water in former pond (2) is got into by the bottom, cathodic area of primary electrolysis groove B, flows out from its top, cathodic area and top, positive column respectively again;

Effusive water body is got into by the bottom, cathodic area of electrolyzer C1 from primary electrolysis groove B cathodic area; Flow out from the top in its positive column and cathodic area respectively again; Effusive water body gets into the bottom, cathodic area of electrolyzer C2 from top, electrolyzer C1 cathodic area; Flow out from its positive column and top, cathodic area then, effusive water body gets into water purification scoop (3) from its top, cathodic area, this moment water purification scoop (3) but in water quality reach the requirement that resource utilization is utilized again; Effusive water body flows into the bottom in electrolyzer C1 cathodic area again from top, electrolyzer C2 positive column; And still return former pond (2) from the effusive water body in top, positive column of electrolyzer C1, carry out cyclic electrolysis;

Effusive water body is got into by the bottom, cathodic area of electrolyzer A1 from primary electrolysis groove B positive column; Flow out from the top in its positive column and cathodic area respectively again; Effusive water body gets into the bottom, cathodic area of electrolyzer A2 from top, electrolyzer A1 positive column; Flow out from its positive column and top, cathodic area then, effusive water body gets into bottom, electrolyzer A1 cathodic area from its top, cathodic area, and effusive water body gets into enriching soln collecting tank (4) from its top, positive column; The nitrate concentration of the interior water body of enriching soln collecting tank (4) this moment reaches the concentration that is fit to carry out biochemical treatment, or is able to carry out electrolytic concentration with high current efficient; And effusive water body still returns former pond (2) from top, electrolyzer A1 cathodic area, carries out cyclic electrolysis.

3. electrochemical appliance according to claim 1 and 2 is characterized in that described cell body is plastic containers, process is anti-corrosion and iron ware or other corrosion-resistant insulation container of insulation processing.

4. electrochemical appliance according to claim 1 and 2 is characterized in that described anode is made up of soluble anode or insolubility anode, and perhaps described anode is connected to form with parallel way by soluble anode and insolubility anode.

5. electrochemical appliance according to claim 1 and 2 is characterized in that described negative electrode is made up of metal or nonmetal electrode.

6. electrochemical appliance according to claim 4 is characterized in that described soluble anode is netted, strip, the tabular or block type electrode of being processed by iron, aluminium and alloy thereof; Described insolubility anode is netted, strip, the tabular or block type electrode of being processed by platinum, iridium, ruthenium, palladium, titanium/ruthenium dioxide or titanium/iridic oxide; The described electrode of being processed by titanium/ruthenium dioxide is the electrode that titanium matrix and ruthenium dioxide coating are composited, and the described electrode of being processed by titanium/iridic oxide is the electrode that titanium matrix and iridic oxide coating are composited.

7. electrochemical appliance according to claim 1 is characterized in that described negative electrode is by palladium, copper, nickel, iron, aluminium or by nonmetal netted, the strip of processing of graphite, tabular or block type electrode.

8. one kind contains negatively charged ion and organic method of wastewater treatment; It is characterized in that using the said electrochemical appliance of claim 1 to carry out the processing of said waste water; Between described anode and described negative electrode, apply DC electric field, the current density of said primary electrolysis groove B is controlled at 0.5-50mA/cm ², the current density of said electrolyzer A is controlled at 2.5-100mA/cm ²The current density of said electrolyzer C is controlled at 0.1-30mA/cm ²

9. one kind contains negatively charged ion and organic method of wastewater treatment; It is characterized in that using the said electrochemical appliance of claim 2 to carry out the processing of said waste water; Between described anode and described negative electrode, apply DC electric field, the current density of said primary electrolysis groove B is controlled at 5-30mA/cm ², the current density of said electrolyzer A1 and A2 is controlled at 30-80mA/cm ², wherein the current density of electrolyzer A2 is greater than the current density of electrolyzer A1; The current density of said electrolyzer C1 and C2 is controlled at 0.5-20mA/cm ², wherein the current density of electrolyzer C2 is less than the current density of electrolyzer C1.

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