JPH10174975A - Fixed bed type porous electrode-containing electrolytic bath and method and apparatus for treating water using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water treatment method with high treatment efficiency in electrochemical treatment of an object matter in the water to be treated by employing a fixed bed type porous electrode-containing electrolytic bath. SOLUTION: A fixed bed type porous electrode-containing electrolytic bath EC is installed, a tank 16 for object liquid to be treated is installed on the bath EC, and a liquid leading means which communicates the electrolytic bath EC and the tank 16 to lead an object liquid to be treated stored in the tank to the electrolytic bath EC by self-weight is also installed. A flow speed control valve to lead a liquid to the electrolytic bath at 0.01-30ml/cm<2> .min per unit surface area of the electrodes in the electrolytic bath is installed and a space to precipitate the object matter to be electrolytically reacted which is contained in the object liquid to be treated is formed at least between respective electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed bed type porous electrode electrolytic cell used for collecting, decomposing and removing impurities in a liquid to be treated. The present invention relates to a method for preventing and recovering from blockage, a method for improving durability, and the like.

[0002]

2. Description of the Related Art At present, various kinds of water are used in our daily lives. For example, well water, tap water, industrial water, pure water, ultrapure water, bathtub water, pool water, etc.

[0003] The used water is industrial wastewater or domestic wastewater. Alternatively, water containing various substances is used in various industries. If these solutes provide appropriate nutrients, or if the temperature of the aqueous solution is a preferable temperature for propagation, microorganisms such as bacteria will propagate and cause deterioration of the performance of the water and various adverse effects. It is known to exert Furthermore, various impurities are contained in factory wastewater and the like, and impurities are removed or useful substances are collected to prevent environmental pollution.

For example, selenium is widely used in products such as sulfuric acid, ceramic products, rectifiers, photovoltaic cells, alloys, pigments, sensitizers, and semiconductors. On the other hand, selenium is harmful. or,
Selenium is separated from the anode mud during copper electrolytic smelting. Since these selenium-related products are also contained in trace amounts in various waste liquids discharged from the manufacturing process or metal refining process, and if they are discharged as they are, they cause pollution, so separation and recovery of selenium from the waste liquids Is strongly required. Not only selenium but also cadmium, chromium, copper, lead, and other heavy metals must reduce the concentration in wastewater to a certain level or less from the viewpoint of pollution prevention, and efficient recovery technology is increasingly desired. ing. Further, recovery of these noble metals or rare metals from waste liquids from various manufacturing processes using noble metals such as gold, silver and platinum or rare metals is strongly demanded from the viewpoint of effective utilization of resources. Therefore, there has been a strong demand for a more efficient method of recovering metals from waste liquid and the like.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for electrochemically treating a target substance in a liquid to be treated using a fixed bed type porous electrode electrolytic cell, wherein the treatment efficiency is improved. It is intended to be.

[0006]

The above object of the present invention is achieved by any one of the technical means (1) to (13) having the following constitution.

[0007] (1) A fixed bed type porous electrode electrolytic cell is filled with 0.1%.
A water treatment method comprising passing a liquid to be treated at a flow rate of 01 to 30 ml / cm ² · min, and electrolytically recovering an electrolytic reaction target contained in the liquid to be treated.

(2) The fixed-bed type porous electrode electrolytic cell and the liquid tank to be treated disposed above it are connected to each other, and the liquid to be treated in the tank is mainly used by utilizing the own weight of the liquid. A water-passing means for passing the liquid through the electrolytic cell, wherein at least a space between each electrode is provided for depositing an electrolytic reaction target contained in the liquid to be treated in the liquid to be treated in the electrolytic cell. Processing equipment.

(3) The liquid to be treated in the liquid tank to be treated, which is provided above the fixed bed type porous electrode electrolytic cell, is passed through the electrolytic cell mainly using its own weight, and the liquid to be treated is A water treatment method, comprising subjecting an electrolytic reaction target contained in a liquid to precipitation in an electrolytic cell and electrolytic recovery.

(4) The fixed-bed type porous electrode electrolytic cell and the liquid tank to be treated disposed above it are connected to each other, and the liquid to be treated in the tank is mainly subjected to the electrolysis by utilizing its own weight. And a flow rate control valve for passing the solution through the electrolytic cell at a flow rate of 0.01 to 30 ml / cm ² · min per unit area of the electrode in the electrolytic cell. A water treatment apparatus characterized by having at least a space between each electrode for depositing an electrolysis target contained in the liquid to be treated in the liquid to be treated in the electrolytic cell.

(5) A valve is provided which sends the liquid to be treated in the tank provided above the fixed-bed type porous electrode electrolytic cell mainly by using its own weight, and which can control the flow rate; 0.01 to 30 ml / cm ² per unit area of the electrode in the electrolytic cell
A water treatment method characterized by flowing the solution at a flow rate of min and electrolytically recovering an electrolytic reaction target contained in the liquid to be treated.

(6) The liquid to be treated is placed in a fixed bed type porous electrode electrolytic cell at a rate of 0.01 to 3 per unit area of the electrode in the electrolytic cell.
A water treatment method for performing electrolytic treatment by passing a liquid at a flow rate of 0 ml / cm ² · min, and electrolytically recovering an electrolytic reaction target contained in the liquid to be treated, wherein the electrolytic gas generated and accumulated in the electrolytic cell In order to prevent the electrolytic efficiency from lowering due to the above-mentioned factors, the gas in the electrolytic cell is expelled by passing the gas through the electrolytic cell at a flow rate of 30 ml / cm ² · min or more periodically or when gas retention is detected. A water treatment method characterized in that:

(7) A water treatment method in which a liquid to be treated is sent to a fixed-bed type porous electrode electrolytic cell and an object of an electrolytic reaction in the liquid to be treated is recovered, wherein a water treatment method is provided downstream of the electrolytic cell. A water treatment method characterized by measuring the concentration of a target component in an installed treatment solution and controlling the flow rate and / or the electrolysis voltage and / or the electrolysis current in the electrolytic cell based on the information.

(8) A water treatment method in which a liquid to be treated is sent to a fixed bed type porous electrode electrolytic cell and an electrolysis reaction target in the liquid to be treated is recovered, wherein a voltage applied to the electrolytic cell is A water treatment method characterized by successively inverting to recover electrolytic deposits.

(9) A water treatment method in which a pump and / or a liquid to be treated is sent to a fixed bed type porous electrode electrolytic cell by using its own weight, and an electrolytic reaction target in the liquid to be treated is recovered. And a method of switching the discharge destination of the water to be treated when reversing the voltage applied to the electrolytic cell.

(10) A plurality of fixed-bed type porous electrode electrolytic cells installed in series are provided, and the electrolytic cells are provided in an amount of 0.01 to 30.
a flow control means for flowing at a flow rate of ml / cm ² · min, and at least a space for electrolytically depositing an electrolytic reaction target contained in the liquid to be treated in the liquid to be treated in the electrolytic cell. A water treatment device, which is provided between each electrode.

(11) A plurality of fixed-bed-type porous electrode electrolytic cells installed in series are provided, and the electrolytic cells are provided in an amount of 0.01 to 30.
a flow control means for flowing at a flow rate of ml / cm ² · min, and at least a space for electrolytically depositing an electrolytic reaction target contained in the liquid to be treated in the liquid to be treated in the electrolytic cell. A water treatment apparatus having a water intake means provided between each electrode and capable of taking a treatment liquid from an electrolytic cell at an arbitrary stage.

(12) A water treatment method characterized by sending a selenium-containing waste liquid to a fixed bed type porous electrode electrolytic cell and electrolytically depositing selenium in the liquid to be treated in the liquid.

(13) A fixed-bed type porous electrode electrolytic cell having a water inlet for the liquid to be treated and a water intake for the treatment liquid for depositing an electrolytic reaction target between the electrodes, wherein each electrode of the electrolytic cell is provided. A fixed bed type porous electrode electrolytic cell, characterized in that a gas venting hole is provided at an upper portion between the gas outlets and a drainage hole is provided at a lower portion thereof.

Hereinafter, the present invention will be described in detail. The fixed-bed-type electrode electrolytic cell of the present invention comprises a pair of a porous electrode or a porous electrode and a plate-like electrode, preferably a mesh-like electrode, alternately formed with one or more, preferably 3 to 15 pairs of electrodes in a tubular or short form. It is arranged in a shaped electrolytic cell and allows the liquid to be treated to flow in a direction substantially perpendicular to the electrode plate, so that it can be used for recovery of metal components and other components in the water to be treated and for electrochemical decomposition and removal of impurities. Things.

The porous electrode of the fixed bed type electrode has a shape corresponding to the electrolytic cell to be used, and is a porous material through which the water to be treated is permeable, for example, granular, spherical, felt, woven, It can be selected from activated carbon, graphite, glassy carbon, carbon-based material such as carbon fiber, or porous metal plate having a shape such as a porous block. The porous electrode used in the water treatment apparatus of the present invention is preferably porous carbon graphite or porous glassy carbon having an average pore diameter of 20 to 150 μm and a porosity of 60% or more. These are, for example, a porous carbon electrode plate obtained by heat-treating a plurality of plant fiber sheets, such as Japanese paper, etc. laminated using an organic binder at a temperature of 1000 ° C. or more in an inert gas atmosphere, and further heat-treating. . A phenol resin, an epoxy resin, or the like can be used as an organic binder used for such a purpose, but the organic binder is not particularly limited to these. Alternatively, a porous body formed by solidifying a carbon-based powder with a pitch or the like, processing it into a block shape, and then firing the same may be used.

When a carbon porous electrode is used, each porous electrode may be composed of one plate-like body, or a metal electrode sandwiched between two carbon porous electrodes may be used. Is also good.

If there is a gap in the electrolytic cell through which the water to be treated flows, through which the liquid can flow without passing through the porous electrode, the treatment efficiency of the water to be treated is reduced. It is preferable to arrange the flow of the water to be treated so as not to cause a short path. Therefore, it is desirable to arrange the carbonaceous electrode in close contact with the electrolytic cell, or by covering the gap between the porous electrode and the electrolytic cell container with a gasket,
This leak flow can be prevented.

Examples of the plate-like electrode include a carbon graphite material, isotropic graphite, glassy carbon, a carbon composite material (a material obtained by mixing a metal with powder in carbon and sintering), or platinum, palladium, nickel or the like. A material carrying the
In addition, dimensionally stable electrodes (platinum oxide coated titanium), platinum coated titanium, nickel, stainless steel, copper, lead,
Although an iron material or the like can be used, it is not particularly limited to these.
The shape can be a flat plate, an expanded mesh, a perforated plate, or the like.

Activated carbon, porous carbon, graphite, glassy carbon, carbon fiber or the like is used as the porous electrode, and a carbon-based material such as graphite is used as the non-porous electrode.
In particular, when treating the water to be treated while generating oxygen gas from the anode, the carbonaceous fixed bed is oxidized by the oxygen gas and dissolved as carbon dioxide gas, or the electrode is easily broken. In order to prevent this, a porous material used as an auxiliary electrode is formed by coating a platinum group metal oxide such as iridium oxide or ruthenium oxide or platinum on a base material such as titanium on the side of the carbonaceous electrode to be polarized positively. The material or reticulated material can be placed in contact so that oxygen evolution occurs primarily on the material.

The electrolytic cell may be a bipolar fixed-bed electrolytic cell in which a fixed-bed porous electrode (preferably a porous carbon electrode) is arranged between a pair of power supply electrodes. The electrode may be used on the electrode side where the electrolytic reaction takes place. For example, in the case where metal ions are electrolytically reduced for precipitation and recovery, the cathode side is preferably a porous electrode and the anode side is preferably a plate electrode. The electrode preferably has a cross-sectional area of 30 to 3000 cm ² .

The distance between the electrodes is preferably 1 mm to 10 cm.

The electrodes are preferably arranged such that the cathodes and the anodes are alternately arranged in the electrolytic cell. The method of supplying power to the electrode pairs arranged in the electrolytic cell may be a parallel type or a serial type.

When the electrode is treated by passing the liquid to be treated, if the flow rate is 30 ml / cm ² · min or more, the treatment by electrolysis is not sufficient. Therefore, increase the number of electrode pairs or connect the electrolytic cell in series. Or a circulating process, but in terms of processing efficiency, 0.01 to 3 in a substantially vertical direction.
It is desirable that the solution is fed at a flow rate of 0 ml / cm ² · min and subjected to electrolytic treatment. Since the flow rate of the liquid sending means is low, it is particularly desirable to send the liquid from the tank of the liquid to be treated, which is installed above the electrolytic cell, by using its own weight. The control of the flow rate and the flow can be adjusted by a valve installed on the flow path. This method is desirably used in combination with a pump or the like, and is particularly used for discharging an electrolytic gas described later to the outside of the electrolytic cell.

Further, by arranging a plurality of electrolytic cells in series, it is also possible to carry out an efficient electrolytic treatment by adjusting the electrolytic conditions such as the flow rate and the voltage / current. For example, a low electrolysis voltage may be applied to the upstream side of a plurality of electrolyzers arranged in series, a higher electrolysis voltage may be applied to the downstream electrolyzer, and metal components to be removed in each electrolyzer may be separated and removed. It is possible.

Alternatively, each is allowed to perform another electrolytic reaction,
The target substance can be recovered by a multi-step reaction.

The voltage applied between the electrodes can be set in accordance with the desired electrolytic reaction. However, in order not to lower the current efficiency, the voltage should be set so that the electrolytic reaction of water does not occur. Is desirable. Specifically, the applied potential is set so that the anode potential is +0.2 to + without substantial oxygen generation.
It is desirable that the cathode potential be 1.2 V (vs. SCE) and the cathode potential is 0 to -1.0 V (vs. SCE) substantially without generation of hydrogen. It fluctuates by the factor. For example, each electrode reaction is performed by each reaction formula and potential as shown in Table 1 below. In Table 1, the potential is vs. It is represented by the standard potential of SHE.

[0033]

[Table 1]

It is also possible to carry out the electrolytic treatment under the condition that the water electrolysis reaction occurs with respect to the intended electrolysis reaction.

When gas is generated during the electrolytic treatment, the generated gas, that is, the oxygen gas and the hydrogen gas are usually generated at a mixing ratio within the explosion limit, and diluted with an inert gas such as air to avoid a danger of explosion. Preferably, for example, a means for separating the electrolytic gas generated at the outlet of the electrolytic cell and a means for diluting the electrolytic gas after separation with air to dilute the electrolytic gas concentration to 4% by volume or less can be provided. . Further, in the case where the gas stays between the electrodes in the electrolytic cell and lowers the electrolysis efficiency, it is desirable to temporarily increase the flow rate to 30 ml / cm ² · min or more to discharge the gas.

It is preferable that the plurality of electrode pairs be housed in a cylindrical body or a short electrolytic cell having upper and lower ends open. Alternatively, the electrodes can be arranged so that the electrode pairs are inserted vertically from the upper opening into the rectangular electrolytic cell. The electrolytic cell container is preferably formed of an electrically insulating material that can withstand long-term use or re-use, and is a synthetic resin such as polyepichlorohydrin, polyvinyl methacrylate, polyethylene, polypropylene, polyvinyl chloride, polyvinyl chloride, and phenol. -Formaldehyde resin, ABS resin,
Acrylic resin, polycarbonate, Teflon resin, or the like, glass, ceramics, insulating-coated metal, water-resistant concrete or wood, or the like can be used. Forming with a transparent material is more convenient because the consumption state of the carbonaceous fixed bed can be visually recognized.

Hereinafter, the electrolytic cell of the present invention will be further described.

Next, a preferred example of a fixed bed type porous electrode electrolytic cell according to the present invention will be described with reference to the accompanying drawings, but the electrolytic cell of the present invention is not limited to this electrolytic cell.

In FIG. 1, for example, a fixed bed type porous electrode 1 of a porous glassy carbon electrode and a metal plate electrode 2 (counter electrode) are arranged in an electrolytic cell container 4 provided with a lid 8. As the counter electrode, for example, a titanium mesh plated with platinum is used, and the cathode and the anode are arranged alternately. If the purpose of the electrolytic treatment is to recover and remove metal ions (cations) by electrolytic reduction, the fixed bed type porous electrode 1 is used as a cathode and the metal plate electrode 2 is used as an anode. Power is supplied from the electrode terminal 9. Each electrode is held by a gasket (for example, made of rubber) 3 so as to be in close contact with the inner surface of the electrolytic cell and, at the same time, to maintain an interval between the electrodes together with the spacer 7. The liquid to be treated is from 0.01 to 5 from the entrance 5 of the electrolytic cell.
Water is supplied at a flow rate of 30 ml / cm ² · min and subjected to electrolytic treatment. The treated water is taken out from the water inlet 6.

The reference numerals shown in FIG. 1 indicate members having the same functions in the following drawings.

FIG. 2 shows an arrangement in which the dimensions of the electrolytic cell container 4 and the electrodes are substantially the same without using the gasket 3, and the electrodes are arranged with almost no gap.

FIG. 3 shows the liquid tank 16 to be treated above the electrolytic cell.
And an electrolytic cell that feeds the solution by using its own weight. In particular, when the purpose is to recover metal ions, it is preferable to flow at a low flow rate from the viewpoint of processing efficiency. The method of utilizing the own weight of the liquid may be such that the electrolytic cell EC and the liquid tank 16 to be treated are integrally arranged as shown in FIG. 3, but it is sufficient that the electrolytic cell is disposed below the liquid storage surface in the tank. If the tank is arranged above the electrolytic cell EC, for example, it is preferable that the tank is arranged as shown in FIGS.
Regarding the method of installing the electrolytic cell, the electrode plate is
(D), (e), (f) may be horizontal,
(B) and (c) may be vertical or oblique. In any case, when an electrolytic gas is generated and stays between the electrodes, the flow rate is periodically or arbitrarily determined to remove the gas. Must be set to 30 ml / cm ² · min or more to push the gas out of the electrolytic cell.
(C), (e) and (f), the pump P and the valve V
Although it is desirable that both V1 and V2 are provided, it is not particularly necessary if the generation of the electrolytic gas can be ignored. In addition to pushing out the gas by increasing the flow rate and flow velocity,
By providing holes 12 for exhaust / drainage between the electrodes as shown in the cross-sectional view of (a), gas staying between the electrodes can be removed.

Further, in FIG. 5 (a), a hole 13 for liquid supply is formed on the lower side so that water can be separately supplied between the electrodes. As a result, the electrolytic gas accumulated between the electrodes can be discharged, and the solid matter generated by the electrolysis (electrolytic deposits separated from the electrodes, broken electrode fragments, etc.) can be discharged out of the electrolytic cell. FIG. 5 (b) is a piping system diagram when a water treatment apparatus is configured by connecting the liquid tank 16 to be treated above the electrolytic cell EC of FIG. 5 (a). Opening / closing control of the pump P and each valve is performed by the sensor 15 for monitoring the concentration of the target component, the electrolytic current, and other information, and the flow rate and the flow path of the liquid to be treated can be switched. In addition, filters F, F ₁ , and F ₂ are appropriately attached.

FIG. 6 shows a horizontal electrolytic cell. Each porous electrode has a structure in which the porous electrode 1 is arranged so as to sandwich a power supply metal electrode 17 formed of a metal plate (mesh shape) for power supply. ing. Thereby, the electrolytic reaction can be more uniformly performed on the entire electrode plate. Besides, as shown in this figure, besides making the electrolytic cell EC a sealed structure with the gasket 3, the upper part can be opened to facilitate electrode replacement.

FIG. 7 shows a water treatment apparatus in which electrolytic cells are arranged in series. On the downstream side of each electrolytic cell EC, a sensor 15 for measuring the concentration of the target component is arranged, and the processing status of the electrolytic cell EC can be monitored. If the first electrolytic cell EC1 cannot complete the processing, the second and third electrolytic cells EC2 and EC3 can further perform the processing.
In addition, the processing conditions of each electrolytic cell can be changed. For example, the voltage can be changed in each of the electrolytic cells EC1, EC2, EC3, etc., and the cells can be processed by different electrolytic reactions.

The electrolytic cell of the present invention can be used for recovering useful components such as noble metals and rare metals from waste liquids and removing various heavy metals or harmful metals.

For example, the present invention can be applied to recovering selenium from a liquid to be treated containing harmful substances such as selenium ions. In particular, the waste liquid from the sulfuric acid production process contains a large amount of metal selenium and selenous acid.
It is said that it usually reaches 0 ppm or more. Known methods for separating selenium include the coprecipitation method using iron hydroxide precipitation and the chemical reduction method, but these methods have poor separation efficiency and are practical in terms of cost and chemical treatment especially when the selenium concentration is low. It was not a target. The method of the present invention can efficiently separate and recover even a trace component such as selenium.

Specifically, the liquid to be treated containing selenium ions is adjusted to a pH of 5 or less, preferably pH 2 or less with an acid (for example, sulfuric acid) or the like, and a reducing agent is added thereto. Perform electrolytic treatment. As the reducing agent, for example, various compounds such as sulfites, bisulfites, sulfur compounds such as thiosulfates, nitrites, arsenous acid, and hydrazine compounds can be used.It is preferable to add them at a concentration of 100 ppm or more. It can be appropriately adjusted according to the concentration of selenium contained in the liquid to be treated. In such a state, by carrying out the electrolytic treatment preferably at a cathode current density of 1 to 5 A / dm ² , the ionic selenium in the liquid to be treated is reduced and precipitated in the aqueous solution as selenium alone.
The precipitated suspended elementary selenium may be collected as it is by filtration or the like. However, the treatment liquid is adjusted to pH 3 to 4 by adding an alkali agent (for example, sodium hydroxide), and agglomerated one is filtered. Means. The amount deposited and deposited on the electrode may be recovered together with the electrode, may be redissolved using a chemical reaction and recovered as a concentrated solution, or may be redissolved by reversing the polarity of the electrode. Although it is possible, especially when a porous carbon electrode is used as the cathode during the electrolytic treatment for selenium recovery, the polarity is inverted to make the porous carbon electrode an anode, so that the porous carbon electrode itself is also used. By disintegrating, selenium deposited on the electrode can be efficiently recovered. The carbon electrode is particularly preferably used because it has high purity and can be easily separated and removed even when the recovered selenium is used as an industrial raw material.

[0049]

Next, the present invention will be described based on examples, but embodiments of the present invention are not limited to these examples.

Example 1 A porous glassy carbon (porosity 67%, average pore diameter) formed by laminating and press-molding a vegetable fiber aggregate and a resin binder using a vegetable fiber aggregate and a resin binder, and firing this molded product 49 μm) was used as a porous electrode (cathode) to prepare the electrolytic cell shown in FIG. Seven pieces of porous carbon graphite having a diameter of 76 mm and a thickness of 9 mm were used. The anode electrode of the counter electrode 2 has a titanium mesh (1 m thick) coated with platinum.
m) was used. Using the electrolytic cell, a water treatment apparatus shown in FIG. 4 (a) was prepared, and a 50 ppm silver-containing waste liquid was 0.1 ml / cm 2.
^The liquid flows at a flow rate of ² min and the cathode current density is 0.9 A / d
The electrolytic treatment was performed at m ² . As a result, the residual silver in the processing solution after passing through the electrolytic cell was 0.1 ppm or less.

Example 2 A porous glassy carbon (porosity: 65%, average pore diameter) produced by laminating and press-molding a vegetable fiber aggregate and a resin binder using a plant fiber aggregate and a resin binder 50 μm) was used as a porous electrode (cathode) to prepare the electrolytic cell shown in FIG. Seven pieces of porous carbon graphite having a diameter of 76 mm and a thickness of 9 mm were used. The anode electrode of the counter electrode 2 has a titanium mesh (1 m thick) coated with platinum.
m) was used. Using the electrolytic cell, a water treatment apparatus shown in FIG. 4 (f) was prepared.
0.05ml / cm ² · mi
The solution was passed at a flow rate of n, and an electrolytic treatment was performed at a cathode current density of 1.0 A / dm ² . As a result, the residual selenium in the treatment liquid after passing through the electrolytic cell was 0.1 ppm or less, and the selenium removal rate at this time was 99.8% or more.

As a comparative example, the lead electrode plates 32 and 33 were
A short electrolytic cell 31 shown in FIG. 8 was provided in the anode chamber 35 and the cathode chamber 36 partitioned by 4 and alternately arranged in both chambers, and the same treatment was performed using this. As a result of performing the electrolytic treatment at a cathode current density of 1.0 A / dm ² , the residual selenium in the treatment liquid was 0.5 ppm.

Example 3 Porous glassy carbon (porosity: 60%, average pore diameter) produced by laminating and press-molding a vegetable fiber aggregate and a resin binder using a vegetable fiber aggregate and a resin binder 55 μm) was used as a porous electrode (cathode) to prepare an electrolytic cell shown in FIG. Two pieces of porous carbon graphite having a diameter of 76 mm and a thickness of 3 mm were used, and seven porous electrodes formed by sandwiching a titanium mesh coated with platinum were used. A titanium mesh (1 mm thick) coated with platinum was used for the anode electrode. Using the electrolytic cell, a water treatment apparatus as shown in FIG.
/ Cm ² · min flow rate and a cathode current density of 1.0
The electrolytic treatment was performed at A / dm ² . As a result, the copper removal rate by passing through the electrolytic cell was 99.9% or more.

[0054]

According to the present invention, it has been clarified that the electrolytic treatment of waste liquid and the like can be carried out more efficiently, and an electrolytic cell, a water treatment apparatus and a treatment method for that purpose can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one example of the electrolytic cell of the present invention.

FIG. 2 is a sectional view showing an example of the electrolytic cell of the present invention.

FIG. 3 is a sectional view showing an example of the water treatment apparatus of the present invention.

FIGS. 4A to 4F are views showing an example of the water treatment apparatus of the present invention.

FIG. 5 (a) is a sectional view showing an example of the electrolytic cell of the present invention. (B) is a piping diagram showing an example of the water treatment apparatus of the present invention using the electrolytic cell of (a).

FIG. 6 is a sectional view showing an example of the electrolytic cell of the present invention.

FIG. 7 is a configuration diagram showing an example of a water treatment device of the present invention.

FIG. 8 is a cross-sectional view of a short electrolytic cell used as a comparative example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Fixed-bed porous electrode 2 Counter electrode 3 Gasket 4 Electrolyzer container 5 Inlet for treated liquid (entrance of electrolytic cell) 6 Outlet for treated liquid (water intake) 7 Spacer 8 Lid 9 Electrode terminal 10 Electrode for power supply 10 ' Power supply electrode 11 Auxiliary electrode 11 'Auxiliary electrode 12 Hole for exhaust / drain between electrodes 13 Liquid supply hole between electrodes 14 Gas-liquid separator 15 Sensor (for monitoring target component concentration) 16 Liquid tank to be treated 17 Power supply Metal electrode 18 Conductor (for power supply) 31 Conventional short type electrolytic cell EC, EC1, EC2, EC3 Fixed bed type porous electrode electrolytic cell

Claims (13)

[Claims] 1. The method according to claim 1, wherein the fixed bed type porous electrode electrolytic cell has a concentration of 0.01 to 0.01.
The liquid to be treated is passed at a flow rate of 30 ml / cm ² · min,
A water treatment method, comprising electrolytically recovering an object of an electrolytic reaction contained in the liquid to be treated. 2. A fixed-bed type porous electrode electrolytic cell and a liquid tank to be treated disposed above the fixed-bed type porous electrode electrolytic cell are connected to each other, and the liquid to be treated in the tank is mainly subjected to the electrolysis by utilizing its own weight. A water-passing means for passing the liquid through the tank, and having at least a space between each electrode for depositing an electrolytic reaction target contained in the liquid to be treated in the liquid to be treated in the electrolytic tank. apparatus. 3. The liquid to be treated in a liquid to be treated tank provided above the fixed-bed type porous electrode electrolytic cell is passed through the electrolytic cell mainly using the own weight of the liquid. A water treatment method characterized by depositing an electrolytic reaction target contained in a cell in an electrolytic cell and electrolytically recovering the same. 4. A fixed-bed type porous electrode electrolytic cell and a liquid tank to be treated disposed above the fixed-cell type porous electrode electrolytic cell are connected to each other, and the liquid to be treated in the tank is used mainly by the own weight of the liquid. And a flow rate control valve for passing the solution through the electrolytic cell at a flow rate of 0.01 to 30 ml / cm ² · min per unit area of the electrode in the electrolytic cell. A water treatment apparatus characterized by having at least a space between each electrode for depositing an object of an electrolytic reaction contained in a liquid to be treated in the liquid to be treated in an electrolytic cell. 5. A valve which sends a liquid to be treated in a tank provided above a fixed-bed type porous electrode electrolytic cell mainly by using its own weight and controls a flow rate, 0.01 to 30 ml / cm ² · mi per unit area of the electrode in the electrolytic cell
A water treatment method comprising passing a solution at a flow rate of n and electrolytically recovering an electrolytic reaction target contained in the liquid to be treated. 6. A fixed bed type porous electrode electrolytic cell is supplied with a liquid to be treated in an amount of 0.01 to 30 ml per unit area of the electrode in the electrolytic cell.
/ Cm ² · min is a water treatment method for performing electrolytic treatment by flowing at a flow rate of / cm ² · min, and electrolytically recovering an electrolytic reaction target contained in the liquid to be treated, such as an electrolytic gas generated or retained in an electrolytic tank. In order to prevent the electrolytic efficiency from being reduced by the
A water treatment method, wherein a gas in an electrolytic cell is expelled by passing a liquid at a flow rate of 0 ml / cm ² · min or more. 7. A water treatment method for sending a liquid to be treated to a fixed bed type porous electrode electrolytic cell and recovering an electrolysis reaction target in the liquid to be treated, wherein the water treatment method is provided downstream of the electrolytic cell. A water treatment method comprising: measuring the concentration of a target component in a treated solution, and controlling the flow rate and / or the electrolytic voltage and / or the electrolytic current in the electrolytic cell based on the information. 8. A water treatment method for sending a liquid to be treated to a fixed-bed type porous electrode electrolytic cell and recovering an electrolytic reaction target in the liquid to be treated, wherein a voltage applied to the electrolytic cell is reduced. A water treatment method characterized by sequentially inverting and collecting an electrolytic deposit. 9. A water treatment method wherein a liquid is sent to a fixed bed type porous electrode electrolytic cell using a pump and / or the weight of the liquid to be treated, and an electrolytic reaction target in the liquid to be treated is recovered. A method of switching the discharge destination of the water to be treated when reversing the voltage applied to the electrolytic cell. 10. A plurality of fixed-bed type porous electrode electrolytic cells installed in series, and the electrolytic cells are provided in an amount of 0.01 to 30 ml / cell.
a flow control means for flowing at a flow rate of cm ² · min, and a space for electrolytically depositing an electrolytic reaction target contained in the liquid to be treated in the liquid to be treated in the electrolytic cell at least by each electrode. A water treatment device characterized by being provided between the water treatment devices. 11. A plurality of fixed-bed type porous electrode electrolytic cells provided in series, and the electrolytic cells are provided in an amount of 0.01 to 30 ml / ml.
a flow control means for flowing at a flow rate of cm ² · min, and a space for electrolytically depositing an electrolytic reaction target contained in the liquid to be treated in the liquid to be treated in the electrolytic cell at least by each electrode. A water treatment apparatus comprising a water intake means interposed therebetween and capable of taking a treatment liquid from an electrolytic cell in an arbitrary stage. 12. A water treatment method comprising sending a selenium-containing waste liquid to a fixed-bed type porous electrode electrolytic cell, and electrolytically depositing selenium in the liquid to be treated in the liquid. 13. A fixed-bed type porous electrode electrolytic cell having a water inlet for a liquid to be treated and a water intake for a treatment liquid for depositing an object of electrolytic reaction between the electrodes, wherein the electrode between the electrodes of the electrolytic cell is provided. A fixed bed type porous electrode electrolytic cell, characterized in that a hole for exhaust and drainage is provided in the upper part of the cell and a hole for liquid supply is provided in the lower part.