KR100654349B1 - An electrolyzer having conductive diamond electrode - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolysis apparatus, and more particularly, to an electrolysis apparatus of a conductive diamond electrode, which is used for sterilization and water quality as an electrolytic solution that is electrolyzed by forming an electrolytic cell and used for wastewater treatment and organic inorganic synthesis. Two electrode holders (1) formed at one side of the outlet port (4) or the inlet port, respectively, and at the other side of the electrode terminal (3) being engaged with each other; An electrolytic cell 2 formed between two electrode holders 1; An electrode provided inside the electrolytic cell 2 and having a conductive diamond film formed thereon; A power supply connected to the electrode; Characterized in that consists of.

Diamond Electrode, Sterilization, Electrolysis, Cleaning

Description

An electrolyzer having conductive diamond electrode

1 is a perspective view showing an electrolysis device of a conductive diamond electrode of the present invention.

2A, 2B, and 2C are diagrams illustrating a non-deposited electrode of the electrolysis device of the conductive diamond electrode of the present invention.

3 is a diagram showing a diaphragm electrode of the electrolysis device of the conductive diamond electrode of the present invention.

Figure 4 is a view showing the inactivation according to the contact time of Legionella bacteria in electrolytically treated tap water.

5 is a view showing the inactivation according to the contact time of Legionella bacteria in tap water to which NaOCl electrolytically treated.

FIG. 6 is a diagram illustrating inactivation of Legionella bacteria according to contact time in DI water added with electrolytically treated NaHCO _3. FIG.

FIG. 7 is a diagram illustrating inactivation of Legionella bacteria with contact time in DI water to which NaSO ₄ is added by electrolytic treatment.

8 is a diagram showing the degree of phenol decomposition when using a diamond electrode and another electrode.

FIG. 9 is a diagram illustrating cyanide decomposition ability when using a diamond electrode and a PbO ₂ electrode. FIG.

 <Brief description of symbols for the main parts of the drawings>

1: electrode holder 2: electrolytic cell

3: electrode terminal 4: outlet

10: one-sided cathode electrode 11: one-sided cathode electrode

12: treatment liquid 14: double-sided coating electrode

15: anode 16: cathode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolysis apparatus, and more particularly, to an electrolysis apparatus of a conductive diamond electrode, which is used for sterilization and water quality as an electrolytic solution that is electrolyzed by forming an electrolytic cell and used for wastewater treatment and organic inorganic synthesis. will be.

Currently, electrolysis devices for water treatment are used in various fields. In this case, when two electrodes are introduced into water and a DC current flows, oxygen gas flows from one electrode (anode) and the electrode in the other direction ( Hydrogen gas is generated in the cathode).

Platinum, precious metals and titanium electrodes are used for the electrodes used in the electrolysis device.

The electrolysis device using electrodes such as platinum and lead dioxide has a simple treatment device, is easy to operate, and can perform oxidation and reduction reactions in other places, but the potential window is narrow, and the electrolysis of water is excellent, and the synthesis Low resolution, low current efficiency and weak electrode stability.

The present invention has been made in view of the above-described problem, and has an object of providing an electrolysis device of a conductive diamond electrode capable of efficient and stable sterilization and disinfection using an electrolysis device using a conductive diamond electrode. .

The present invention is the discharge or inlet is formed on each side in order to achieve the above object, the electrode terminal is formed on the other side of the two electrode holder is fixed to each other; An electrolytic cell formed between two electrode holders; An electrode provided inside the electrolytic cell and in which a conductive diamond film is formed; A power supply connected to the electrode; The electrolytic cell is a non-diaphragm and is provided with a single-sided cathode electrode and a one-sided cathode electrode coated only on one surface with a diamond coating, and a treatment solution passes between the one-sided anode electrode and the one-sided cathode electrode, or the electrolytic cell is a diaphragm with a single-sided anode electrode. A double-sided coating electrode is provided between the single-sided cathode electrodes, the treatment liquid passes between the single-sided cathode electrode and the cathode of the double-sided coating electrode, and between the anode and the single-sided cathode electrode of the double-sided coating electrode, or the electrolytic cell is a diaphragm. Two or more double coated electrodes are provided between the cathode electrodes, between the cathode of the one-sided electrode and the both-side coated electrode, the anode of the two-sided coated electrode, and then between the cathode of the two-sided coated electrode, and between the anode and the one-sided coated electrode. The treatment liquid passes through, or the electrolytic cell is provided with a single-sided cathode electrode and a single-sided cathode electrode, and a diaphragm is installed between the one-sided anode electrode and the one-sided cathode electrode. The treatment liquid is characterized in that flows separately between the one-sided positive electrode and the diaphragm and between the one-sided negative electrode and the diaphragm, respectively, the outlet or inlet is formed on one side, the electrode terminal is formed on the other side is interlocked and fixed to each other Two electrode holders; An electrolytic cell formed between two electrode holders; An electrode provided inside the electrolytic cell and having a conductive diamond film formed thereon; A power supply connected to the electrode; A treatment liquid which adds NaOCl or NaCl to a concentration of Cl ₂ oxidizing agent to be 0.6 ppm or more and passes through the electrolytic cell; It provides an electrolysis device of a conductive diamond electrode composed of.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

The theoretical breakdown voltage required to cause electrolysis of water is about 1.2 volts, but practically no electrolysis is possible at this voltage. Electrolysis requires a voltage of at least 1.2 volts and the lowest voltage required for electrolysis of water is called the potential window. The difference between the potential at which the generation of oxygen starts and the potential at which the generation of hydrogen starts becomes the potential window, which varies depending on the type of electrode.

A conductive diamond (BDD) electrode is a p-type semiconductor with a band cap of about 5.5 eV doped with boron. The backband potential does not change between the surface terminator and the adsorbed species, but the potential becomes about 1 Vvs.NHE in the state of polycrystalline hydrogen termination. Even when not dope, conductivity occurs due to the presence of a surface level or the presence of an amorphous component including a trace sp structure. Despite being in the p-type semiconductor, it is presumed that the reduction current flows because the potential is involved. As the amount doped with boron increases, the conductivity increases, and at 10000 ppm, it becomes a metalloid state. The lattice constant of diamond is 0.3567 nm, eight of which are carbon atoms. The number of carbon atoms and boron atoms per unit volume is 1.76 × 10 ²³ cm ⁻³ {= 8 / (0.3567 × 10 ⁻⁷ ) ³ }, and 1.76 × 10 ²¹ cm ⁻³ , respectively.

Electrodes, such as platinum and precious metal titanium electrodes, are about 2 volts, but diamond electrodes have a wide potential window of up to 3-5 volts. If the potential window is wide, instead of water electrolysis, the redox reaction of a material which is difficult to be electrolytically can be proceeded preferentially. By using such physical properties, it is possible to decompose or synthesize materials that were impossible in the conventional electrochemical system.

Diamond electrodes have twice as wide a potential window as platinum. This is due to the electrochemical stability of the diamond surface and reflects the redox of the surface, which is a small reaction in the discharge of water, from proceeding. This characteristic allows high current density to flow, and it can be used up to 600 ° C and is also strong against reverse potential, thus detecting chemical species that could not be measured until now. In addition, reactions other than oxygen and hydrogen gas generation are also possible. There are precious metals such as platinum as industrial anode materials, but the redox potential window is narrow, and each of the oxidation reactions occupies a weight.

In addition, it is possible to maximize the efficiency by applying a high voltage because the current and voltage range that can not be used in the existing electrodes can be freely selected.

In the conventional electrode, it was difficult to use because of the low efficiency of the electrolytic cell because it is forced to flow a low current, but since the high voltage can be applied to the diamond electrode, the generation of hydrogen peroxide is 30 times higher than that of the platinum electrode.

To explain the chemical characteristics of the reaction of electrolysis of pure water, the diamond electrode is the standard electrode potential of oxygen and 1.23 V vs. A large potential difference is formed at the electrode-solution interface because there is almost no reaction even when an overvoltage of 1 V or more is applied from the NHE. The anode is then maintained at a sufficient potential to produce active oxygen such as OH radicals, hydrogen peroxide, and ozone.

When the electrolysis can be used as an extreme data representing Oxidation film of ion-exchanged in the water pure, in the case of Pt electrodes O ₃ is 0.2 H ₂ O ₂ 0.005 is produced, in the case of PbO2 electrode O ₃ is 5 H ₂ O ₂ is generated 0.001, while in the case of diamond electrode BDD O ₃ is produced 2 H ₂ O ₂ is 0.15.

Ozone, when coexisted with hydrogen peroxide, becomes an advanced oxidation process (AOP) and OH radicals are produced quickly.

O ₃ + H ₂ O ₂ = OH + HO ₂ + O ₂

^{_{HO 2 = O 2 - + H}} +, pKa = 4.8

The product generated during the low concentration of 300 ppm and 30 mAcm −2 NaCl in the halide ions produces hypochlorite which is twice as fast as platinum, and can finally detect a large amount of perchlorate ion.

When synthesizing or decomposing using a diamond anode, it is essential to consider the effects of peroxides and OH radicals, and the generation of radicals is possible not only in oxidative decomposition but also in polymamination and corbe reaction.

The conductive diamond electrode is hardly affected by the electrolysis of water. Therefore, utilizing the advantages of the conventional electrochemical system has become the basis for building an electrochemical system that solves the problems that were difficult in the prior art.

The diamond electrode is made of niobium or silicon, and the surface of the diamond electrode is covered with conductive diamond, so that 100% of the conductive diamond can be used.

In the present invention, the polycrystalline conductive diamond is made of a chemically stable electrode material and exhibits high oxygen and voltage in aqueous solution. By using these characteristics, the electrolysis apparatus of the electroconductive diamond electrode for the purpose of controlling bacteria containing Legionella bacteria is comprised.

Compared with the conventional electrode system and the conductive diamond electrode system, the advantages of the conventional electrode are that the processing apparatus is simple, the operation is simple, and the oxidation and reduction reactions can be performed elsewhere, but the advantage is the conductive diamond electrode system. The same is true for.

The disadvantages of the conventional electrode system are that the potential window is narrow, the electrolysis of water is excellent, the synthetic decomposition capacity is low, the current efficiency is low, and the electrode stability is weak. It has a wide window, suppresses the electrolysis of water, has high synthetic decomposition ability, high current efficiency, and safe electrode.

The present invention provides an electrolysis apparatus for a conductive diamond electrode capable of efficient and stable sterilization and disinfection using the characteristics of the diamond electrode.

Detailed embodiments of the present invention will be described below.

As shown in FIG. 1, in the electrolytic apparatus of the conductive diamond electrode of the present invention, electrode holders 1 are formed on both sides of the electrolytic apparatus 2 so as to surround the outside of the electrolytic cell 2, and are fixed by bolts, etc., and one side of the electrode holders 1. The electrode terminal 3 is connected to the anode and the cathode. In addition, an outlet 4 through which the electrolytically treated water is discharged is formed at one side of the electrode holder 1, and an inlet (not shown) through which the water to be electrolyzed is introduced at the other side is formed. The electrode holder 1 is preferably a polypropylene product.

A pump may be installed to supply water to the inlet of the electrode holder 1, and a DC power source or an AC power source may be connected to the electrode.

Referring to the embodiment in which the conductive diamond electrode is provided in the present invention, as shown in Figure 2a, when forming a membrane-free electrolytic cell, the treatment liquid 12 between the one-side anode electrode 10 and the one-side cathode electrode 11 This will pass. In this way, a redox reaction occurs between the one-sided anode electrode 10 and the one-sided cathode electrode 11.

The one-sided anode electrode 10 and the one-sided cathode electrode 11 are diamond coating electrodes, and the conductive diamond coating is formed on only one surface thereof. Since the electroconductive diamond film shows the characteristic of the above-mentioned diamond electrode as it is, high current and voltage can be applied and the efficiency of an electrolytic cell can be improved significantly.

In FIG. 2B, a two-layer non-deposited electrolytic cell is illustrated, and one-sided anode electrode 10 and one-sided cathode electrode 11 are provided, and a double-sided coated electrode 14 is provided therebetween.

The double-sided coated electrode 14 is coated with a conductive diamond film on one surface to form an anode 15, and the diamond film is coated on the other surface to form a cathode 16, which is the same below. The treatment liquid 12 flows between the one-sided positive electrode 10 and the negative-electrode 16 surface of the double-sided coated electrode 14, and is disposed between the positive-side 15 and the one-sided negative electrode 11 of the double-sided coated electrode 14. This flow leads to a redox reaction.

In FIG. 2C, a three-layer non-deposited electrolytic cell is illustrated, and one-sided anode electrode 10 and one-sided cathode electrode 11 are provided, and two double-sided covering electrodes 14 are provided therebetween.

The processing liquid flows between the one-sided anode electrode 10 and the cathode of the double-sided coating electrode 14, and the processing liquid flows between the anode of the double-sided coating electrode 14 and the cathode of the other double-sided coating electrode 14, The processing liquid flows between the positive electrode of the electrode 14 and the single-sided negative electrode 11 to form three electrolytic cells.

As described above, when the electrolytic cell is formed with a diaphragm having a simple structure without a flow path switching valve, the ph is neutral and the residual chlorine is increased, which is suitable for disinfection.

3 shows an electrolytic cell with a diaphragm. In this case, a diaphragm 17 is provided between the one-sided anode electrode 10 and the one-sided cathode electrode 11, and water does not pass through the membrane, but only ions. To pass. Thus, acid and alkali are separated and ph is separated. This system should be equipped with complicated devices such as flow path switching valves and sterilization efficiency will be increased in case of separated acidic water.

The stability of Legionella bacteria in the electrolyzed water electrolyzed by the electrolytic apparatus of the conductive diamond electrode as described above is as follows.

In the anode or cathode, an electrode in which a polycrystalline conductive diamond film is formed on a silicon substrate by hot filament CVD is used. The electrolyzer uses an electrolytic area of 65 cm2 and the electrolytic solution uses tap water, tap water with NaCl, ion exchange water with NaHCO ₃ , or DI water with Na ₂ SO ₄ . The electrolytic solution supply amount of the electrolyzer is set at 160 l / h, and electrolysis is performed at a current density of 50 mA / cm ² below the electrolytic solution temperature of 22-26 ° C. 5 ml of Legionella bacteria is added to each electrolyzed water, and the number of live Legionella bacteria is measured after 5 minutes, 20 minutes, and 60 minutes.

As can be seen in the graph of FIG. 4, in the tap water, Legionella was not inactivated even after 60 minutes of contact time, but Legionella was inactivated in the treated tap water. Electrolyzed tap water with a current density of 50 mA / cm ² or 100 mA / cm ² had oxidant concentrations of 0.11 ppm and 0.13 ppm, but there was no significant difference in the Legionella inactivation rate. On the other hand, in comparison with the oxidation of 0.19 ppm of tap water electrolytically treated with a current density of 150 mA / cm ^2, the inactivation rate of Legionella was more than three times higher than that of electrolytic densities of 50 and 100 mA / cm ² . . The longer the contact time is, the longer the inactivation of Legionella bacteria progresses, and after 60 minutes, the inactivation of Legionella bacteria reaches 89%.

5 shows inactivation of Legionella bacteria in tap water to which NaOCl was added. Legionella bacteria in tap water containing 0.18 ppm, 0.67 ppm, and 1.12 ppm of NaOCl in terms of Cl 2 can be inactivated.

Legionella is completely inactivated after 5 minutes of contact time in tap water containing 0.67 ppm NaOCl and 1.12 ppm NaOCl.

Figure 6 shows the inactivation of Legionella bacteria in DI water added with electrolytically treated NaHCO ₃ . The DI water added with NaHCO ₃ was electrolyzed to approximately the same as the ionic strength in tap water. The Legionella bacteria of DI water added with electrolytic treatment with NaHCO ₃ were inactivated, and after 60 minutes of contact time, the inactivation rate was 70-80% regardless of the oxidizer concentration.

When the diamond electrode is electrolyzed with NaHCO ₃ solution or NaCO ₃ solution, peroxygen is generated, and active species such as peroxygen contribute to inactivation of Legionella.

FIG. 7 is a graph showing inactivation of Legionella bacteria in DI water added with NaSO ₄ by electrolytic treatment, and electrolyzed DI water with Na ₂ SO ₄ added to tap water to have the same ionic strength. Legionella bacteria in DI water containing conventionally treated Na ₂ SO ₄ hardly activated, and the inactivation rate after 60 minutes of contact time was 20% or less.

As can be seen from the above experiments, Legionella was not activated in tap water electrolyzed with diamond electrodes. And active species such as percarbonate contributes to the inactivation of Legionella bacteria, and persulfate has little effect on inactivation of Legionella bacteria.

Therefore, the concentration of peracid in the electrolyzed water is increased by electrolytic treatment of tap water with low concentration of NaCl, and the Legionella bacteria are inactivated in the short sand.

When NaOCl or NaCl is added to the treatment liquid 12 so as to be 0.6 ppm or more at a Cl ₂ conversion oxidizer concentration, sterilization and water quality maintenance can be most ideal.

An electrolysis device using conductive diamond can be used to form a system for purifying the pool.

8 shows the degree of phenol decomposition when a diamond electrode and another electrode are used. As can be seen in the figure, the diamond electrode has excellent resolution when applied with a low voltage.

9 shows the cyanide decomposition ability when using a diamond electrode and a PbO ₂ electrode. Cyanide was almost decomposed at 10 hours after the diamond electrode, and cyan was completely decomposed after 60 hours at the PbO ₂ electrode.

The electrolytic apparatus of the conductive diamond electrode of the present invention generates electrolytically treated electrolyzed water using an electrode having a simple structure, and can use the electrolyzed water to sterilize and maintain water quality of the pool, and to oxidatively decompose organic and inorganic compounds. You can do And to remove harmful substances such as cyan and phenol, there is an effect that can remove heavy metals.

The electrode used in the electrolytic cell is an electrode having a conductive diamond film formed thereon, which has a wide potential window and thus can apply high voltage and current, thereby increasing the efficiency of the electrolytic cell.

By placing a double-sided coating electrode between the one-sided coating electrode of the positive electrode and the negative electrode, the electrolytic cell can be easily constructed to prepare sterilized water. The concentration of peracid in the electrolyzed water is increased by electrolyzing tap water containing low concentration of NaCl. So you can easily sterilize and disinfect.

In addition, the electrolysis device of the present invention can easily make a two-chamber electrolyzer using a non-diaphragm one chamber or an ion exchange membrane, it is formed into a bipolar has the effect that can easily increase the electrolytic cell to five chambers.

Claims (6)

Two electrode holders 1 each having an outlet 4 or an inlet formed on one side thereof, and an electrode terminal 3 formed on the other side thereof to be engaged with and fixed to each other; An electrolytic cell 2 formed between the two electrode holders 1; In the electrolysis device of the conductive diamond electrode, characterized in that consisting of an electrode having a conductive diamond film is formed to be connected to the power supply inside the electrolytic cell (2), The electrolytic cell 2 is provided with a single-sided positive electrode 10 and a single-sided cathode electrode 11 in which only one surface of the diamond coating is coated with a non-detachable film, and between the single-sided anode electrode 10 and the one-sided cathode electrode 11, 12) Electrolysis device of the conductive diamond electrode, characterized in that passing through. delete The method of claim 1, wherein the electrolytic cell 2 is provided with a double-sided coating electrode 14 between the one-sided positive electrode 10 and the single-sided cathode electrode 11 as a non-detachable membrane, the single-sided positive electrode 10 and the double-sided electrode ( An electrolysis device for a conductive diamond electrode, characterized in that the treatment liquid 12 passes between the cathode 16 of the 14 and between the anode 15 of the double-sided coated electrode 14 and the one-sided cathode electrode 11. 2. The electrolytic cell 2 according to claim 1, wherein two or more double-sided coating electrodes 14 are provided between the single-sided cathode electrode 10 and the single-sided cathode electrode 11 as a non-detachable membrane, and the single-sided cathode electrode 10 and the double-sided electrode 2 are provided. Between the cathode 16 of the covering electrode 14 and the anode 15 of the double-sided coating electrode 14 and then the cathode 16 of the double-sided coating electrode 14 and the anode 15 of the double-sided coating electrode 14 and Electrolytic device of a conductive diamond electrode, characterized in that the processing liquid 12 passes between the single-sided cathode electrode (11). The method of claim 1, wherein the electrolytic cell 2 is provided with a one-sided cathode electrode 10 and a one-sided cathode electrode 11, a diaphragm 17 between the one-sided anode electrode 10 and the one-sided cathode electrode 11, And the treatment liquid 12 flows separately between the one-sided positive electrode 10 and the diaphragm 17 and between the one-sided negative electrode 11 and the diaphragm 17, respectively. Two electrode holders 1 formed at one side of an outlet port 4 or an inlet port, respectively, and having electrode terminals 3 formed on the other side thereof to be engaged with each other; An electrolytic cell 2 formed between two electrode holders 1; An electrode provided inside the electrolytic cell 2 and having a conductive diamond film formed thereon; A power supply connected to the electrode; A treatment liquid 12 which adds NaOCl or NaCl so as to be 0.6 ppm or more at a Cl ₂ conversion oxidant concentration and passes through the electrolytic cell 2; Electrolysis device of a conductive diamond electrode composed of.

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