CN113772787B - Electrochemical filter for removing total nitrogen in water - Google Patents
Electrochemical filter for removing total nitrogen in water Download PDFInfo
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- CN113772787B CN113772787B CN202111134302.4A CN202111134302A CN113772787B CN 113772787 B CN113772787 B CN 113772787B CN 202111134302 A CN202111134302 A CN 202111134302A CN 113772787 B CN113772787 B CN 113772787B
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/46104—Devices therefor; Their operating or servicing
- C02F1/46109—Electrodes
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/46104—Devices therefor; Their operating or servicing
- C02F1/46109—Electrodes
- C02F2001/46152—Electrodes characterised by the shape or form
- C02F2001/46157—Perforated or foraminous electrodes
- C02F2001/46161—Porous electrodes
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- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
- C02F2101/163—Nitrates
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
- C02F2101/166—Nitrites
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Abstract
The invention belongs to the technical field of water treatment, and discloses an electrochemical filter for removing total nitrogen in water. The invention can shorten the mass transfer distance of the material to the surface of the electrode by utilizing the micron-sized aperture electrode, increases the collision chance of pollutants and the electrode in the liquid flowing process by utilizing the nano tip structure in the pore passage, limits the reaction ions in the internal channel of the three-dimensional nano tip porous electrode, weakens the repulsion action of the same-polarity ions under the action of electric field force, and solves the problems of small effective reaction area of the electrode, overlarge distance between two poles, low mass transfer efficiency, low reaction efficiency, reactant rejection of the electrode, accumulation of reaction gas, difficult amplification of the reactor and the like of the traditional electrochemical reactor.
Description
Technical Field
The invention belongs to the technical field of water treatment, and particularly relates to an electrochemical filter for removing total nitrogen in water.
Background
Electrochemistry is an effective water treatment technology for reducing nitrate radical by utilizing electrons and active hydrogen to generate nitrogen, and the technology has the advantages of no pH limitation, retention of other salt, no generation of concentrated solution, no need of adding chemicals, no back flush, easy automation control, stable effect, rapid reaction and the like, and is widely researched and applied.
Electrochemical reactor structures have been extensively studied as an important factor affecting electrochemical redox efficiency. The plate-groove type reactor is the most studied electrocatalysis reactor, but the plate-type electrode has the defects of small effective reaction area, overlarge two-stage distance of the electrode, limited mass transfer and inhibition of adsorption and oxidation-reduction reaction due to the exclusion of nitrate anions by a cathode. And cathodically reducing the species (e.g. NH) 3 ,NO 2 - ) May be re-oxidized at the anode of the plate and tank reactor, which reduces the overall faraday efficiency. In addition, oxygen gas generated at the anode dissolves in the electrolyte and diffuses to the cathode where competing oxygen reduction reactions consume electrons at the cathode. More importantly, O is generated by the oxygen evolution reaction occurring at the anode 2 Re-oxidation of nitrites to nitrates is described in the research of the Nitrogen Cycle by Electrochemical Reduction of Nitrate, progress and sites and Removal of nitrates by Electrochemical in non-chloride medium of efficiency of the anode material. One strategy is to place an ion exchange membrane between the anode and cathode and divide one chamber into two. A cation exchange membrane for blocking anionsThe ions pass from the cathode to the anode chamber so that side reactions are minimized to some extent. However, ion exchange membranes are often clogged with carbonate or organic compounds during use, see Critical Review of Pd-Based Catalytic Treatment of Priority controls in Water and Optimization of the cathode material for anode removal by a particulate electrolysis process. Furthermore, in view of the limitations of batch reactors (e.g. limited reaction area and capacity) and the difficulties of scale-up, innovative membrane reactors under certain flow conditions, which achieve the Reduction of silver Nitrate by the combined effect of the membrane's retention function and electrochemical Reduction, see electrochemical Reduction of Nitrate Using magnesium Phase TiO 2 Reactive Electrochemical Membranes with Pd-Based Catalysts and Electro-oxidation of organic polar by Reactive Electrochemical Membranes. The electrochemical membrane reactor needs to apply a certain external pressure to ensure the flow of liquid, and gas generated in the reaction process is easy to stay in the reactor, so that the membrane reactor has certain potential safety hazard.
Furthermore, the main problem of the electroreduction of nitrate on the electrodes is the low reduction rate due to the low mass transport. This considerable disadvantage limits their use in large scale applications (mass transport of nitrate to the electrode surface and diffusion of by-products from the electrode surface in solution are the main rate-limiting processes of electrochemical nitrate reduction, increasing the electrode surface area naturally contributing to faster nitrate reduction) therefore, electrodes should have liquid channels for reactant transport and gas channels for product separation, see Catalytic nitrate removal from water, past, present and future properties, electrochemical reduction of nitrate, and Catalytic pore side reactor electrochemical flow cells.
These problems have not been solved effectively, and the practical application of the electrochemical technology in removing the total nitrogen in the water body is limited.
Disclosure of Invention
The invention aims to provide an electrochemical filter for removing total nitrogen in water and a using method thereof.
The technical scheme of the invention is as follows:
an electrochemical filter for removing total nitrogen in water comprises a cathode tank cover 3, a cathode binding post 1, a water inlet 2, a cathode reaction tank 8, a sealing rubber mat 4, a three-dimensional nano tip porous cathode 5, a filter tank main body 6, a support column 7, an anode reaction tank 9, a three-dimensional nano tip porous anode 10, a screw 11, an anode tank cover 14, an anode binding post 12 and a water outlet 13;
the filter tank main body 6 is of a concave structure, the interior of the filter tank main body is divided into a cathode reaction tank 8 and an anode reaction tank 9 by a support pillar 7 which protrudes along the inner wall, two sides of the support pillar 7 are respectively provided with a three-dimensional porous cathode 5 and a three-dimensional porous anode 10, and a sealing rubber pad 4 is arranged between the three-dimensional nano tip porous cathode 5 and the three-dimensional tip porous anode 10 and the support pillar 7; the two sides of the filter tank main body 6 are respectively provided with a cathode tank cover 3 and an anode tank cover 14, and the whole fixation is realized through a screw 11; the cathode tank cover 3 is provided with a water inlet 2 which is positioned at the oblique lower part; the anode tank cover 14 is provided with a water outlet 13 which is positioned above the anode tank cover in an inclined way; the cathode wiring terminal 1 and the anode wiring terminal 12 are respectively arranged on the cathode tank cover 3 and the anode tank cover 14, and the horizontal position is 5-30 mm higher than the horizontal position of the water outlet 13.
The three-dimensional nanometer tip porous cathode 5 is prepared by taking a metal wire mesh, a modified metal wire mesh and a material containing a pore channel structure as substrates and preparing an electrode with a nanometer tip structure by methods such as etching, anodic oxidation, a template method, spraying, electrophoresis and the like. The three-dimensional nanometer tip porous anode 10 is an electrode which is prepared by taking a metal wire mesh, a modified metal wire mesh and a material containing a pore channel structure as substrates, preparing a nanometer tip structure through methods such as etching, anodic oxidation, a template method, spraying, electrophoresis and the like, and coating an active layer.
When the three-dimensional nanometer tip porous cathode 5 and the three-dimensional nanometer tip porous anode 10 are formed by pressing by taking a metal wire mesh as a substrate, the thickness of the metal wire mesh is 0.2-2 cm, the diameter range of holes of the metal wire mesh is 0.001-2 mm, and the thickness of the pressed three-dimensional nanometer tip porous electrode is 0.2-2 cm.
The metal wire mesh is iron, copper, aluminum, titanium, zinc, nickel or stainless steel mesh.
The active layer is a tin oxide layer, a zinc oxide layer or a ruthenium iridium titanium layer.
The cathode containing the pore structure is an electrode with a foam structure, a honeycomb structure and a hole punched in an integral material.
Further, the electrochemical filter operates according to the following steps:
step 1: the water to be treated is continuously injected into the cathode reaction tank 8 from the water inlet 2 at a certain flow speed, and the water sequentially and respectively flows through the internal pore canals of the three-dimensional nano tip porous cathode 5 and the three-dimensional nano tip porous anode 10 under the action of gravity, then is accumulated in the anode tank 9, and flows out of the reactor after reaching the position of the water outlet 13.
And 2, step: an external voltage-stabilizing direct-current power supply is started, and the relation between the applied current and the effective reaction area of the three-dimensional nano tip porous electrode is 0.5-20 mA/cm 2 。
Further, in the step 1, the concentration of total nitrogen in the water body to be treated is 0-500 mg/L, the conductivity of the water body is not less than 10mS/cm, if the conductivity of the water body is less than 10mS/cm, a certain amount of sodium chloride can be added for regulation, and the concentration of the sodium chloride in the added water body is 0.5-30 g/L.
In the step 1, the reaction time is controlled by regulating and controlling the flow rate of the liquid injected into the reaction tank body.
The calculation formula of the effective reaction area of the three-dimensional porous electrode in the step 2 is as follows:
S horizontal bar ＝π×d×W×n Cross bar
S Vertical shaft ＝π×d×L×n Vertical
S Is effectiveArea of ＝(S Horizontal bar +S Vertical )/2
Wherein S is Horizontal bar Is the effective reaction area (cm) of the horizontal screen surface of the wire mesh 2 ) D is the wire mesh diameter (cm), W is the width (cm) of each wire mesh, n Cross bar Number of transverse wires per wire-mesh, S Vertical shaft Is the effective reaction area (cm) of the vertical wire surface of each wire mesh 2 ) L is the length (cm) of each wire mesh, n Vertical Number of longitudinal wires contained per wire mesh sheet, S Effective area Is the total effective area (cm) of each piece of wire mesh 2 )。
Further, the reaction formula of the electrochemical filter for removing the total nitrogen in the water body is as follows:
the cathode involves the reaction:
NO 3 - +H 2 O+2e - ＝NO 2 - +2OH - 1
NO 3 - +3H 2 O+5e - ＝1/2N 2 +6OH - 2
NO 3 - +6H 2 O+6e - ＝NH 3 +9OH - 3
NO 2 - +4H 2 O+4e - ＝NH 2 OH+5OH - 4
2NO 2 - +4H 2 O+6e - ＝N 2 +8OH - 5
2NO 2 - +3H 2 O+4e - ＝N 2 O+6OH - 6
NO 2 - +H 2 O+2e - ＝NO+2OH - 7
N 2 O+5H 2 O+4e - ＝2NH 2 OH+4OH - 8
reaction involved in the anode:
2Cl - ＝Cl 2 +2e - 9
Cl 2 +H 2 O＝HOCl+Cl - +H + 10
HOCl＝ClO - +H + (11)
2NH 4 + +3HOCl＝N 2 +5H + +3Cl - +3H 2 O 12
NO 2 - +HClO＝NO 3 - +H 2 O+Cl - 13
compared with the prior art, the electrochemical filter is characterized in that:
(1) The three-dimensional nano tip porous electrode has a larger effective reaction area, and reactive sites are increased;
(2) The three-dimensional nanometer tip structure existing in the pore channel increases the collision chance of pollutants and the surface of an electrode in a continuous flow electrochemical filter, and promotes mass transfer;
(3) The micron-sized aperture of the electrode can shorten the mass transfer distance of nitrate anions to the surface of the cathode, and simultaneously, the nitrate anions are limited in the cathode pore channel to participate in the reduction reaction, so that the adverse effect of the anion migration to the anode under the action of electric field force on the reduction reaction of the cathode is weakened;
(4) The micron-sized aperture of the electrode can shorten the mass transfer distance of the ammonium cations to the surface of the anode, and simultaneously limit the ammonium cations in the anode pore channel to participate in the oxidation reaction, thereby weakening the adverse effect of the migration of the cations to the cathode under the action of electric field force on the oxidation reaction of the anode;
(5) In the use process of the electrochemical filter, the cathode is positioned in front of the anode relative to the liquid flow direction, so that ammonium ions (which are easily adsorbed on the surface of the cathode and occupy active sites) generated after the nitrate is reduced by the cathode are transferred to the anode along with the flow of the liquid, and the rate of reducing the nitrate by the cathode is improved;
(6) During the use of the electrochemical filter, the cathode is positioned in front of the anode relative to the flow direction, and the influence of oxygen, which is a substance generated by the anode, on the reduction of the cathode is minimized;
(7) During the use process of the electrochemical filter, the position of the cathode is positioned in front of the anode relative to the flow direction, and the hydrogen ions generated by the anode can adjust the pH value of the effluent to a certain extent;
(8) The invention adopts the matching of the cathode and the anode, can simultaneously remove nitrate ions, nitrite ions and ammonium ions in water, and generates nitrogen;
(9) Pressure is not required to be applied to the liquid to be treated in the reaction process, and the liquid to be treated realizes gravity self-flow through the regulation and control of the pore diameter of the pore channel;
(10) The electrochemical filter has simple structure, does not need stirring, is easy to realize functional unitization and is convenient for engineering amplification application.
Drawings
FIG. 1 is a schematic diagram of an electrochemical filter for removing total nitrogen in water according to the present invention.
Fig. 2 is an overall view of an electrochemical filter for removing total nitrogen in water according to the present invention.
FIG. 3 is a scanning electron micrograph of a three-dimensional nanotip porous cathode.
FIG. 4 is a scanning electron micrograph of a three-dimensional nanotip porous anode.
FIG. 5 is a graph of the concentration of nitrogen-containing contaminants in effluent after treatment with an electrochemical filter of the present invention using a three-dimensional porous electrode with and without nanotip structures.
FIG. 6 shows the concentration of nitrogen-containing contaminants in the effluent of an electrochemical filter of the present invention with different three-dimensional nanotip cathode and anode sequences.
FIG. 7 is a comparison of the concentration of nitrogen-containing contaminants in effluent using three-dimensional nanotip porous cathode, anode channels (Flow-through) and surface (Flow-by) electrochemical filters of the present invention.
In the figure: 1. the device comprises a cathode binding post, 2. A water inlet, 3. A cathode tank cover, 4. A sealing rubber gasket, 5. A three-dimensional nanometer tip porous cathode, 6. A filter tank main body, 7. A support column, 8. A cathode reaction tank, 9. An anode reaction tank, 10. A three-dimensional nanometer tip porous anode, 11. A screw, 12. An anode binding post, 13. A water outlet, 14. An anode tank cover.
Detailed Description
In order to further illustrate the present invention, the following examples are given in detail, but they should not be construed as limiting the scope of the present invention.
Example 1
A preparation method of a ruthenium-iridium-titanium porous anode containing a nano tip structure comprises the following preparation steps:
(1) Pretreatment of the titanium wire mesh substrate: and (2) placing the titanium silk screen into a mixed acid solution containing hydrofluoric acid, nitric acid and high-purity water for treatment for 10s to remove the oxide film on the surface, wherein the volume ratio of the hydrofluoric acid to the nitric acid to the high-purity water in the mixed acid solution is 1. Then, in a water bath kettle with a constant temperature of 90 ℃, the oil stain on the titanium substrate is removed by treating the titanium substrate with 30wt.% of NaOH solution for 30 min.
(2) Acid etching: and (3) putting the washed titanium wire mesh into an oxalic acid solution with the mass fraction of 10%, etching for 1.5 hours in a constant-temperature water bath kettle at 90 ℃, and washing residual oxalic acid and titanium oxalate on the surface of the substrate with a large amount of water after treatment. And then storing the mixture in ethanol for later use.
(3) Forming a nano tip: preparing an ammonium fluoride electrolyte with the mass fraction of 0.02%, anodizing for 60min under the condition of constant pressure of 30V, rinsing with ethanol, and then carrying out thermal oxidation treatment for 3h.
(4) Coating of the middle layer: and (3) preparing 0.01mmol of Sn coating liquid in isopropanol, uniformly coating the middle layer coating liquid on a titanium wire mesh substrate containing a nano tip structure, drying at 120 ℃ for 10min, then carrying out thermal oxidation at 475 ℃ for 15min, cooling to room temperature, taking out, repeating the steps for 3 times, and carrying out the last thermal oxidation for 1.5h.
(5) Coating of an active layer: the metal salts of ruthenium trichloride, iridic chloride and titanium trichloride are mixed according to a proportion and dissolved in isopropanol to form the active layer coating liquid. The concentrations of ruthenium, iridium and titanium in the coating liquid of the active layer in the step (5) are respectively 0.1-0.6mg/mL, 0.3-1.5mg/mL and 0.2-1.3mg/mL. And (3) uniformly coating the active layer coating liquid on the nano tip titanium wire mesh substrate coated with the middle layer, drying at the temperature of 120 ℃ for 10min, thermally oxidizing at the temperature of 475 ℃ for 15min, cooling to room temperature, taking out, repeating the steps for 7 times, and finally thermally oxidizing for 1.5h. After cooling to room temperature, the porous anode containing the nanotip structure is obtained, and the nanotip structure is shown in fig. 4.
Example 2
A preparation method of a porous cathode containing a nanotip structure comprises the following preparation steps:
(1) Pretreatment of the wire mesh substrate: the wire netting is put into 0.5mol/L hydrochloric acid to remove an oxide layer, then ultrasonic treatment is carried out in ethanol solution for 10min, and then the wire netting is soaked in 1mol/L sodium hydroxide solution for 30min to remove pollutants on the surface of the material.
(2) Anodic oxidation: then controlling the current density to be 15mA/cm in 2mol/L sodium hydroxide electrolyte at the constant temperature of 40 DEG C 2 And oxidizing the anode for 10min to obtain the three-dimensional nanometer tip porous cathode as shown in figure 3.
Example 3
The embodiment is described with reference to fig. 1, and the electrochemical filter for removing total nitrogen in water in the embodiment includes a cathode tank cover 3, a cathode terminal 1, a water inlet 2, a cathode reaction tank 8, a sealing rubber mat 4, a three-dimensional nanotip porous cathode 5, a filter tank main body 6, a support column 7, an anode reaction tank 9, three-dimensional nanotip porous anodes 10 and 11, an anode tank cover 14, an anode terminal 12, and a water outlet 13;
the water inlet 2 of the electrochemical filter is positioned at the side of the cathode reaction tank 8 and is positioned at the oblique lower part of the cathode tank cover 3; the water outlet 13 is positioned at the side of the anode reaction tank 9 and is positioned above the anode tank cover 14 in an inclined way; the horizontal positions of the cathode terminal 1 and the anode terminal 12 are 15mm higher than the horizontal position of the water outlet 13.
The three-dimensional nanometer tip porous cathode 5 is formed by pressing five iron wires, the size of each iron wire is 10cm multiplied by 0.05cm, the aperture of meshes of the iron wires is 1mm, and a nanometer tip structure is prepared on the iron wires in an anodic oxidation mode. The three-dimensional nanometer tip porous anode 10 is a stable anode which takes a titanium wire mesh as a substrate, the surface of the anode is provided with a nanometer tip structure prepared by anodic oxidation, tin oxide as an intermediate layer and ruthenium-iridium-titanium as an active layer, and the overall size of the anode is 10cm multiplied by 0.05cm.
The use method of the electrochemical filter comprises the following steps: continuously injecting nitrate-containing nitrogen with concentration of 50 mg/min from the water inlet 2 at the speed of 10mL/minAnd (3) allowing an aqueous solution with the concentration of L and sodium chloride of 1g/L to enter a cathode reaction tank 8, allowing the water to sequentially flow through the internal pore channels of the three-dimensional nano tip porous cathode 5 and the three-dimensional nano tip porous anode 10 respectively under the action of gravity, accumulating in an anode tank 9, treating for 30min, and allowing the water to flow out of the reactor after reaching the position of a water outlet 13. The results are shown in FIG. 5, with a constant current of 2mA/cm being applied 2 And the effluent treated by the electrochemical filter is almost free of nitrite nitrogen and ammonium nitrogen, the removal rate of the total nitrogen of the electrochemical filter containing the electrode with the nanometer tip structure reaches 94%, and the removal performance of the total nitrogen of the electrochemical filter without the electrode with the nanometer tip structure is improved by 32.3%.
Example 4
An electrochemical filter was assembled as in example 1.
The use method of the electrochemical filter comprises the following steps: continuously injecting water solution containing nitrate nitrogen with concentration of 50mg/L and sodium chloride with concentration of 1g/L into a cathode reaction tank 8 from a water inlet 2 at a speed of 10mL/min, wherein the water body sequentially and respectively flows through the three-dimensional nanotip porous cathode 5 and the inner pore channels of the three-dimensional nanotip porous anode 10 under the action of gravity and then is accumulated in an anode tank 9 (the water body of a control group sequentially flows through the three-dimensional nanotip porous anode 10, then flows through the three-dimensional nanotip porous cathode 5 under the action of gravity, reaches the position of a water outlet 13 after being treated for 30min and then flows out of the reactor. As shown in FIG. 6, a constant current of 2mA/cm is applied 2 Through comparing the sequence of the liquid passing through the three-dimensional nanometer tip cathode and the anode, the flow mode that the liquid to be treated passes through the anode and then the cathode is found out, nitrate nitrogen is detected in effluent, a large amount of ammonia nitrogen and nitrite nitrogen exist at the same time, and the removal rate of total nitrogen is only 48%. However, if the liquid to be treated passes through the cathode and then passes through the anode, the effluent contains a small amount of nitrate nitrogen, almost no nitrite nitrogen and ammonia nitrogen exist, the total nitrogen removal rate is 94%, and the total nitrogen removal rate is improved by 46% compared with the liquid flow mode of passing through the anode and then passing through the cathode.
Example 5
An electrochemical filter was assembled as in example 1.
The use method of the electrochemical filter comprises the following steps: and continuously injecting an aqueous solution containing 50mg/L of nitrate nitrogen and 1g/L of sodium chloride from the water inlet 2 at a speed of 10mL/min into the cathode reaction tank 8, wherein the water body sequentially and respectively flows through the three-dimensional nanotip porous cathode 5 and the internal pore channel (Flow-through) of the three-dimensional nanotip porous anode 10 under the action of gravity, then is accumulated in the anode tank 9 (the water body in the comparison group sequentially and respectively flows through the three-dimensional nanotip porous cathode 5 and the surface (Flow-by) of the three-dimensional nanotip porous anode 10 under the action of gravity), and then flows out of the reactor after reaching the position of the water outlet 13 after being treated for 30 min. The results are shown in FIG. 7, with a constant current of 2mA/cm being applied 2 After the wastewater is treated by using the surfaces of the three-dimensional nanometer tip cathode and anode, the removal rate of the total nitrogen is 65 percent. After the three-dimensional nanometer tip cathode and anode pore channel treatment, the total nitrogen removal rate is 94%, which is improved by 29% compared with the total nitrogen removal rate by using the three-dimensional nanometer tip cathode and anode surface method.
Example 6
An electrochemical filter was assembled as in example 1, using the method: continuously injecting production catalysis wastewater into the cathode reaction tank 8 from the water inlet 2 at the speed of 10mL/min, wherein the total nitrogen concentration of the inlet water is 25mg/L, and the water body sequentially flows through the three-dimensional nanotip porous cathode 5 and the inner pore channels of the three-dimensional nanotip porous anode 10 respectively under the action of gravity, accumulates in the anode tank 9, is treated for 90min, reaches the position of the water outlet 13 and then flows out of the reactor. During the whole process, 2mA/cm is applied to the electrochemical filter 2 Is constant current. The removal rate of total nitrogen in effluent water reaches over 96 percent, and the energy consumption is 0.19 kW.h/g (TN).
Example 7
An electrochemical filter was assembled as in example 1, using the method: continuously injecting aquaculture water into the cathode reaction tank 8 from the water inlet 2 at the speed of 5mL/min, wherein the total nitrogen concentration of the influent water is 40mg/L, and the water sequentially flows through the three-dimensional nanotip porous cathode 5 and the three-dimensional nanotip porous anode 10 in sequence under the action of gravity, accumulates in the anode tank 9, is treated for 60min, reaches the position of the water outlet 13 and then flows out of the reactor. Machine for finishingIn the process, 2mA/cm was applied to the electrochemical filter 2 Is constant current. The removal rate of total nitrogen in effluent water reaches more than 89%, and the energy consumption is 0.26 kW.h/g (TN).
Example 8
An electrochemical filter was assembled as in example 1, using the method: and continuously injecting metallurgical wastewater into the cathode reaction tank 8 from the water inlet 2 at the speed of 5mL/min, wherein the total nitrogen concentration of the inflow water is 172mg/L, the water sequentially flows through the three-dimensional nanotip porous cathode 5 and the inner pore channels of the three-dimensional nanotip porous anode 10 respectively under the action of gravity, is accumulated in the anode tank 9, and flows out of the reactor after reaching the position of the water outlet 13 after being treated for 60 min. During the whole process, the electrochemical filter is applied with 2mA/cm 2 The removal rate of total nitrogen in effluent reaches more than 85 percent by constant current, and the energy consumption is 0.081 kW.h/g (TN).
Claims (5)
1. An electrochemical filter for removing total nitrogen in water is characterized by comprising a cathode tank cover (3), a cathode binding post (1), a water inlet (2), a cathode reaction tank (8), a sealing rubber mat (4), a three-dimensional nano tip porous cathode (5), a filter tank main body (6), a support column (7), an anode reaction tank (9), a three-dimensional nano tip porous anode (10), a screw (11), an anode tank cover (14), an anode binding post (12) and a water outlet (13);
the filter tank main body (6) is of a concave structure, the interior of the filter tank main body is divided into a cathode reaction tank (8) and an anode reaction tank (9) by a support column (7) which is convex along the inner wall, two sides of the support column (7) are respectively provided with a three-dimensional nano tip porous cathode (5) and a three-dimensional nano tip porous anode (10), and a sealing rubber gasket (4) is arranged between the three-dimensional nano tip porous cathode (5) and the three-dimensional nano tip porous anode (10) and the support column (7); the two sides of the filter tank main body (6) are respectively provided with a cathode tank cover (3) and an anode tank cover (14), and the whole body is fixed through a screw (11); the cathode tank cover (3) is provided with a water inlet (2) which is positioned at the oblique lower part; a water outlet (13) is arranged on the anode tank cover (14) and is positioned obliquely above the anode tank cover; the cathode wiring terminal (1) and the anode wiring terminal (12) are respectively arranged on the cathode tank cover (3) and the anode tank cover (14), and the horizontal position is 5-30 mm higher than that of the water outlet (13);
when the three-dimensional nanometer tip porous cathode (5) and the three-dimensional nanometer tip porous anode (10) are formed by pressing with a metal wire mesh as a substrate, the thickness of the metal wire mesh is 0.2-2cm, the hole diameter range of the metal wire mesh is 0.001-2 mm, and the thickness of the pressed three-dimensional nanometer tip porous electrode is 0.2-2 cm.
2. The electrochemical filter for removing the total nitrogen in the water as claimed in claim 1, wherein the three-dimensional nano tip porous cathode (5) is an electrode with a nano tip structure prepared by etching, anodic oxidation, template method, spraying and electrophoresis with a metal wire mesh, a modified metal wire mesh and a material containing a pore channel structure; the three-dimensional nanometer tip porous anode (10) takes a metal wire mesh, a modified metal wire mesh and a material containing a pore channel structure as substrates, and is used for preparing a nanometer tip structure through etching, anodic oxidation, a template method, spraying and electrophoresis, and is coated with an electrode of an active layer.
3. The electrochemical filter for removing total nitrogen in water of claim 2, wherein the metal wire mesh is iron, copper, aluminum, titanium, zinc, nickel or stainless steel mesh.
4. The electrochemical filter for removing total nitrogen in water as claimed in claim 2, wherein the active layer is a tin oxide layer, a zinc oxide layer or a ruthenium iridium titanium layer.
5. The electrochemical filter for removing total nitrogen in water according to claim 2, wherein the cathode containing the pore structure is a foam structure, a honeycomb structure, or a perforated electrode made of a monolithic material.
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| CN202111134302.4A CN113772787B (en) | 2021-09-27 | 2021-09-27 | Electrochemical filter for removing total nitrogen in water |
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| CN202111134302.4A CN113772787B (en) | 2021-09-27 | 2021-09-27 | Electrochemical filter for removing total nitrogen in water |
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