KR20070113551A - The combined process method and unit equipment using ozone-electrolysis/semiconductor catalysis for treatment of non-degradable waste - Google Patents

Abstract

An ozone electrolysis/semiconductor catalyst complex apparatus for treating a non-degradable waste water and a using method thereof are provided to improve waste water treating efficiency and economic efficiency by generating much more OH radicals than conventional AOP(Advanced Oxidation Process). An ozone electrolysis/semiconductor catalyst complex apparatus for treating a non-degradable waste water comprises a plurality of electrodes(140a,140b,140c,210a,210b,210c) including anodes and cathodes, a power supplier(120a,120b,120c,130a,130b,130c) supplying currents to the electrodes, an electrolysis bath(500), a semiconductor catalyst(200a,200b,200c) and an ozonizer(190). A distribution stone(170) for maximizing contact of the ozone and the waste water is installed on the floor of the electrolysis bath. The semiconductor catalyst is filled in a tray, and such trays are multiply stacked within a multi-stepped catalyst support structure(200a,200b,200c). The cathode and the anode are installed to the each ends on which the trays are inserted. An equalization space is existed on the upper portion of the semiconductor catalyst layer to mix the ozone and the waste water smoothly. A circulation system recirculates the waste water partially to the reaction bath. The top layer of the multi-stepped catalyst support structure comprises active carbons(160) which are filled into a mesh net of a basket shape.

Description

The Combined Process Method and Unit Equipment using Ozone-Electrolysis / Semiconductor Catalysis for Treatment of Non-degradable Waste}

1 is a schematic diagram showing one embodiment in which the entire apparatus of the composite apparatus according to the present invention is integrated.

Figure 2 is a graph showing the results of the generation of OH radicals generated in the device of the composite device according to the present invention.

Figure 3 is a graph showing the comparison of the experimental results of decomposing the radioactive organic waste liquids (EDTAs) in each of the three different devices and conventional conventional process according to the present invention.

Figure 4 is a graph showing the comparison of the experimental results of decomposing the hardly decomposable industrial waste liquid (PCE) in the composite apparatus according to the present invention and other conventional processes.

<Explanation of symbols for main parts of the drawings>

(100): Ozone outflow outlet, (110): Waste fluid outlet

(120a): 3-stage positive power supply, (120b): 2-stage positive power supply

(120c): 1 stage positive power supply, (130a): 3 stage positive power supply

(130b): 2-stage positive power supply cable, (130a): 1-stage positive power cable

140a: three-stage anode electrode, 140b: two-stage anode electrode

140c: one-stage anode electrode, 150: waste liquid inlet

160: activated carbon, 170: ozone diffuse stone

(180): semiconductor catalyst, activated carbon filling mesh, (190): ozone generator

(200a): three stage semiconductor catalyst, (200b): two stage semiconductor catalyst

(200c): one-stage semiconductor catalyst, (210a): three-stage cathode electrode

(210b): two-stage cathode electrode, (210c): one-stage cathode electrode

(220a): three-stage negative power supply connection line, (220b): two-stage negative power supply connection line

220c: 1st stage negative power supply connection line, 240: Wastewater internal circulation pump

(250): wastewater internal circulation outlet, (260): wastewater internal circulation outlet

(270): Wastewater internal circulation inlet valve (280): Insulator

(290): wastewater internal circulation inlet, (300): wastewater inflow

(400): wastewater outflow, (500): multi-stage reactor

The present invention relates to an ozone-electrolysis / semiconductor catalyst composite device for difficult-decomposable waste liquid treatment and a method of using the same. More specifically, in order to generate more OH radicals for the decomposition of hardly degradable contaminants in the wastewater than the conventional AOP method, in order to increase the efficiency and economic efficiency of the hardly degradable waste liquid treatment, an electrode including a cathode and an anode, the electrode Ozone-electrolysis / semiconductor catalyst for refractory waste liquor treatment including a power supply for supplying current to the electrolysis tank, an electrolysis tank for treating wastewater, a semiconductor catalyst filled in the electrolysis tank, and an ozone generator for supplying ozone to the electrolysis tank. A composite device, comprising: a diffusion stone installed at the bottom of the electrolysis tank to subdivide ozone bubbles to maximize contact between ozone and waste water; A tray filled with the semiconductor catalyst and a multi-stage catalyst support structure in which the trays are stacked in multiple layers; A cathode and an anode installed at each stage into which the respective trays filled with the semiconductor catalyst are inserted; An equalization space that facilitates mixing of the ozone and wastewater and is present in the upper portion of the semiconductor catalyst layer filled in each tray; A circulating system which allows oxidatively treated waste water to be partially recycled to the bottom of the reactor as needed; And the uppermost layer of the multi-stage catalyst support structure is for the ozone-electrolysis / semiconductor catalyst composite device for the hardly decomposable waste liquid treatment, characterized in that the activated carbon is filled in a basket-type mesh network.

In general, an advanced oxidation treatment apparatus (AOP) is a method in which OH radicals generated in water by single or combined means of O ₃ / H ₂ O ₂ , O ₃ / UV, O ₃ / UV / H ₂ O ₂ , and TiO ₂ / UV are used. Decomposing organic matter is more efficient than simple oxidation (oxidants or heat). Oxidation treatment using ozone is applied to the atmosphere or water treatment, and electrolysis belongs to the electrochemical field using an oxidation-reduction process, but in general, these methods have disadvantages of low treatment efficiency.

Recently, a water treatment method using a combination of ozone and a catalyst has been attempted, but practical use thereof is not active, and electrolysis is also applied by coating a semiconductor catalyst material on the surface of an electrode.

Existing advanced oxidation treatment devices that are currently applied and applied to ozone (O ₃ ), hydrogen peroxide (H ₂ O ₂ ) alone or combined means and ozone (O ₃ ), UV, TiO ₂ photocatalyst alone or combined means OH radicals are generated to oxidatively decompose organic materials. Since ozone and hydrogen peroxide use methods must be artificially infused with hydrogen peroxide, there are disadvantages in terms of economic and maintenance such as chemical cost and process control.

Ozone and UV (254nm) are ozone absorbing ultraviolet rays and photoly decompose and generate OH radicals through the ozone decomposition mechanism in water, which is more efficient and easier to maintain than ozone and hydrogen peroxide. However, due to the significant reduction of the UV intensity according to the irradiation distance of UV and turbidity of water, there remains a problem of economic and practicality in the field application.

TiO ₂ / UV method produces OH radicals on the surface of the photocatalyst by irradiating UV to the photocatalyst to oxidatively decompose organic materials. However, TiO ₂ powder can be used for water pollutant removal and sterilization. Recovery problems and disadvantages of the above-described UV.

In addition, these conventional single or combined means of advanced oxidation treatment processes are generally slow processing speed, selectivity for hardly degradable pollutants remains a problem in the field application.

Among the inventions related to the treatment of hardly decomposable organic matter using the conventional TiO ₂ coating layer, Japanese Patent Application Laid-Open No. 2000-51863 and Pyeongseong 11-10157 are provided with a cathode-cathode electrode at regular intervals and installed at right angles to the hot water flow direction. Electrolysis method using photocatalytic semiconductor which is installed by coating photocatalyst (TiO ₂ , ZnO) or coating photocatalyst (TiO ₂ , ZnO) on lattice-shaped wires and hydroxy radical generation method by ozone / ultraviolet lamp The present invention relates to decomposing low concentrations of organic substances in a treatment tank using a combination of ozone and electrolysis.

However, to date, OH radicals for the decomposition of hardly degradable contaminants in wastewater are generated much more than the conventional AOP method, so as to increase the efficiency and economic efficiency of the hardly degradable waste liquid treatment, an electrode including a cathode and an anode, and a current to the electrode. Combined device for ozone-electrolysis / semiconductor catalyst for refractory waste liquid treatment including a power supply for supplying water, an electrolysis tank for treating wastewater, a semiconductor catalyst filled in the electrolysis tank, and an ozone generator for supplying ozone to the electrolysis tank. In the, the electrolysis tank is installed on the bottom of the diffuser to subdivide the ozone bubbles to maximize the contact between the ozone and waste water; A tray filled with a semiconductor catalyst and a multi-stage catalyst support structure in which the trays are stacked in multiple layers; A cathode and an anode installed at each stage into which each tray filled with the semiconductor catalyst is inserted; Equalization space to facilitate the mixing of ozone and wastewater, and exists in the upper portion of the semiconductor catalyst layer filled in each tray; A circulating system which allows oxidatively treated waste water to be partially recycled to the bottom of the reactor as needed; In addition, no ozone-electrolysis / semiconductor catalyst composite device for hardly decomposable waste liquid treatment, characterized in that the uppermost layer of the multi-stage catalyst support structure includes activated carbon filled in a basket-type mesh network. .

Therefore, the present invention generates much more OH radicals for the decomposition of hardly degradable contaminants in the wastewater than the conventional AOP method, so as to improve the efficiency and economics of the hardly degradable waste liquid treatment, and ozone-electrolysis / An object of the present invention is to provide a semiconductor catalyst composite device and a method of using the same.

An ozone-electrolysis / semiconductor catalyst complex apparatus for treating a hardly decomposable waste liquid according to the present invention includes: a diffusion stone installed at the bottom of an electrolysis tank to subdivide ozone bubbles to maximize contact between ozone and waste water; A tray filled with a semiconductor catalyst and a multi-stage catalyst support structure in which the trays are stacked in multiple layers; A cathode and an anode installed at each stage into which each tray filled with a semiconductor catalyst is inserted; An equalization space that facilitates mixing of ozone and wastewater and is present in the upper portion of the semiconductor catalyst layer filled in each tray; A circulatory system that allows the decomposed wastewater to be partially recycled to the bottom of the reactor as needed; And the uppermost layer of the multi-stage catalyst support structure is characterized in that the activated carbon is filled in the basket-type mesh network.

In addition, the present invention is a method for treating hardly degradable wastewater using the apparatus, comprising: injecting wastewater into a monolayer reactor; Mixing the injected waste water with the multi-layer and the activated carbon filled with the semiconductor catalyst as closely as possible; Supplying power to each cathode and anode of the multilayer; Mixing ozone generated by generating ozone in the ozone generator with the wastewater injected into the multi-layer reactor through the ozone diffusion stone; The charged semiconductor catalyst is in contact with an electrode of an electrolysis device installed on the side of the wastewater treatment reactor, and electrons are excited in the ground state (base state) to be in the conduction band; Dissolving ozone at each stage of the multi-stage reactor configured in the multi-stage reactor in contact with the electrode and the charged semiconductor catalyst to receive electrons from the electrodes and convert them into ozonide (O ^- ₃ ); And ozonide rapidly produces HO ₃ , which decomposes into OH radicals and oxygen; Its purpose is to provide a method of use that includes.

According to the constituent characteristics of the invention, a multistage layer filled with a semiconductor catalyst (ZnO, TiO ₂ ) is filled between an anode (stainless steel, TiO ₂ -Ir coated) -cathode (platinum, TiO ₂ coated, TiO ₂ -Ir coated) electrode. Configure. In each layer, the combined action of the electron supplied from the electrode and the ozone and semiconductor catalyst supplied from the lower side maximizes the amount and rate of generation of hydroxy radicals, which have the greatest effect on organic decomposition performance and process efficiency. It is characterized by a complex device for the treatment of industrially generated hardly decomposable organic waste liquids, including generated hardly decomposable radioactive organic waste liquids.

In the composite device apparatus part of the present invention, a diffusion stone for generating a small drop of ozonized gas is generated at the bottom of the wastewater treatment reactor so that the ozone generated in the high and low frequency silent discharge method is applied and the ozone flowing into the reactor is dissolved in water. It is composed of a multistage layer in the reaction tank, and is configured to make uniform contact between the charged semiconductor catalyst and the electrodes separately installed in each stage and dissolved ozone, and the number of multistage layers depends on the injection concentration and throughput of the target wastewater. It is configured to make the mixing of dissolved ozone and the target waste water smoothly by putting an equal space on the upper part of the semiconductor catalyst layer filled in each stage, and circulating the waste water treated by oxidative decomposition treatment to the bottom of the reactor if necessary. Betcher for wastewater treatment to improve the decomposition rate of high-degradability, non-degradable wastewater The single batch treatment process of the present invention can be configured by continuously installing one or more reactors, and by increasing the treatment capacity and decomposition efficiency of the hardly decomposable wastewater by such a continuous treatment process, environmental emission standards can be improved. Can satisfy.

According to the technical characteristics of the composite apparatus of the present invention, dissolved ozone is contacted with an electrode and a charged semiconductor catalyst at each stage of a multi-layer composed of a wastewater treatment reactor and receives electrons from the electrode and is converted into ozonide (O ^- ₃ ), and ozonide Rapidly produces HO ₃ , which decomposes into OH radicals and oxygen.

At this time, the filled semiconductor catalyst is in contact with the electrode of the electrolysis device installed on the side of the wastewater treatment reactor, and the electrons are excited in the ground state (base state) to be in the conduction band.

Therefore, the present invention is characterized by generating a large amount of OH radicals compared to the conventional waste liquid treatment apparatus using an ozone-electrolysis / semiconductor catalyst to increase the efficiency of the hardly decomposable wastewater treatment and to shorten the treatment time effectively. do.

In addition, in the present invention, ozone is not significantly affected by the turbidity of the wastewater, and the catalyst is easily recovered by molding and filling the semiconductor catalyst into granules.

Therefore, the present invention generates much more OH radicals that can easily decompose pollutants including industrially-generated, non-degradable organic wastes generated by nuclear power plants, thereby increasing the efficiency of wastewater treatment and shortening the treatment time. There is an advantage that can be shortened.

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

However, the following embodiments are only intended to describe the present invention in detail by way of example and are not intended to limit the scope of the invention to the contents of the embodiments.

As shown in FIG. 1, a composite apparatus and apparatus for treating a biodegradable organic waste generated in an industrial facility including a non-degradable radioactive organic waste generated by a nuclear power plant according to the present invention are ozone using a high and low frequency silent discharge method for generating ozone. Generator 190, anodes 140a, 140b, 140c are stainless steel, TiO ₂ -Ir coated electrode, cathodes 210a, 210b, 210c are platinum, TiO ₂ coated, TiO ₂ -Ir coated electrode The ZnO, TiO ₂ and semiconductor catalysts 200a, 200b and 200c were respectively formed in the wastewater treatment reactor 500 by molding into decomposition granulators 140a to 140c and 210a to 210c and granular. 180) and a multistage layer having three constructional layers having an insulator 280 attached therebetween.

The voltages and currents required for the anode and cathode stages of the multi-stage layer are separately provided at the power supply devices 120a, 120b, and 120c, and anode connection portions 130a, 130b, and 130c, and cathode connection portions 220a, 220b, and 220c, respectively. It is configured to maximize the current density used for the electrode installed in each stage by supplying to each stage independently by). In addition, the multi-layer organic waste liquid composite processing apparatus of the present invention is not limited to the configuration that can be composed of only three multi-layers, it can be configured by installing three or more multi-stage layer continuously, such a multi-layer By constitution, the decomposition rate of high concentration hardly degradable organic waste liquid can be improved, and the environmental emission standard can be sufficiently satisfied.

The wastewater 300 introduced through the inlet 150 installed at the bottom of the reactor 500 is decomposed and processed through the multiple stages of the three stages, and the outlet 400 is discharged through the outlet 110, and a circulation pump 270 if necessary. And it is configured to enable the batch operation using the inlet valve 260 and the outlet valve 270 for circulation.

In addition, in the case of using a batch process for treating a high concentration of hardly degradable organic waste liquid, the uppermost layer is a circulating pump 240 for treating the treated wastewater on the upper part of the reactor using a layer filled with the activated carbon 160 in the basket mesh mesh 180. ) And valves 260 and 270 to have circulating flows 250 and 290 inside the reactor to increase the decomposition treatment residence time required for waste liquid treatment in the ozone-electrolysis / semiconductor catalyst complex in the wastewater treatment reactor 500. Can be increased. The activated carbon layer used in the present invention contributes to the simple physical adsorption of organic matter and is accompanied by the desorption process of organic matter, so that it can be used for a long time, and if necessary, the amount of waste generated can be reduced by regenerating activated carbon.

By applying the ozone-electrolysis / semiconductor catalyst composite device for the treatment of difficult-to-decomposable waste liquids configured as described above, it is possible to maximize the amount and rate of generation of hydroxy radicals that have the greatest effect on organic decomposition performance and process efficiency. Industrial facilities, including radioactive organic waste liquids to improve the efficiency of treatment of difficult to decompose organic waste and characterized in that the treatment time is made shorter and more effective even in the treatment of high concentration of difficult to decompose organic waste.

Specific experimental results according to the ozone-electrolysis / semiconductor catalyst composite apparatus and apparatus for the hardly degradable waste liquid treatment of the present invention operated as described above are as follows.

FIG. 2 shows the amount of OH radicals generated by the ozone / electrode / semiconductor catalyst composite apparatus for treating a hardly decomposable waste liquid using a TiO ₂ -Ir coated electrode and a TiO ₂ granular semiconductor catalyst according to the present invention. The amount produced by the UV / TiO ₂ device was compared and observed at a current density of about 20 (mA./cm ² ). As shown in FIG. 2, the reaction time represents the amount of OH radicals generated by ozone self-decomposition up to 6 minutes, and after 6 minutes, an ozone-electrolysis / semiconductor catalyst complex apparatus and apparatus for hardly decomposable waste liquid treatment. When the OH radicals are generated, a much larger amount of OH radicals than the amount generated by ozone self-decomposition is an ozone-electrolysis / semiconductor catalyst complex device for treating a hardly degradable waste liquid of the present invention, and a method of using the same. It can be seen that the amount of OH radicals generated about 10 times higher than that of UV / TiO ₂ devices.

3 is a chemical cleaning waste solution generated during decontamination of a nuclear power plant (steam generator, etc.) and a system using an ozone-electrolysis / semiconductor catalyst composite device and other three processes for difficult-degradable waste liquid treatment according to the present invention. The experimental results were analyzed by applying to each of the EDTA (Ethylene Diamine Tetra Aceticacid), which is classified as a representative non-degradable radioactive organic waste solution. In the experimental conditions and the results of FIG. 3 in Table 1, and the reaction time for 10 minute and then the positive electrode, a negative electrode both TiO ₂ -Ir using the coated electrode, and TiO ₂ particulate catalyst that only the ozone with the filled single layer / electrode / catalyst The decomposition efficiency of the composite device (GPI Co., Ltd. AOP device) was 98.6%, while the other processes showed a degradation efficiency of 75-92%. As a result of measuring the reaction byproducts after the decomposition reaction, the ozone / electrode / semiconductor catalyst composite device had almost no decomposition byproducts after the reaction for 2 hours.

4 is a comparison of the experimental results obtained by decomposing the ozone / electrode / semiconductor catalyst composite device for treating the hardly degradable waste liquid according to the present invention and applying the other two processes to PCE (Tetrachloroethylene), which is a representative hardly degradable toxic substance, respectively. . Two cases of the conventional ozone process and the present invention device are ZnO semiconductor catalyst, anode is made of stainless steel, cathode is Pt electrode and both TiO ₂ -Ir coated electrode is used and TiO ₂ granular semiconductor catalyst is used. The results of the performance evaluation on the decomposition of PCE are presented for two cases of ozone / electrode / semiconductor catalyst composites for difficult-to-decompose waste liquid treatment using. As shown in FIG. 4, when the reaction time of the composite device according to the present invention is 20 minutes, the concentration of PCE is already about 1.3 ppm, and thus the non-selective advantage is obtained even in the shortest time toxic contaminants. It has been shown that there is a characteristic of generating radicals, so that the water treatment efficiency is high, and the treatment time can be shortened much.

EDTA Degradation Performance Comparison Item JIPIEN AOP Device O ₃ + TiO ₂ + UV Wet oxide Electrolysis Initial concentration (ppm) 290 290 300 300 Electrode Supply Voltage 30 V - - 1.3 V (SCE) Ozone dosage 25-30 mg dm ^-3 min ^-1 29.3 mg dm ^-3 min ^-1 - - UV intensity (I ₀ ) - 6.1 × 10 ¹⁶ hυml ^-1 min ^-1 - H ₂ O ₂ - 2 × 10 ^-2 mol / ℓ -  catalyst - Co (II): 2 × 10 ^-4 mol / l -

In the present invention, since only one method of using ozone, which is one of the existing water treatment methods, is selective in directly decomposing water pollutants and there is an insufficient amount of generation of OH radicals, it is non-selective by converting ozone into OH radicals. It is not selective for the decomposition of water pollutants such as double bonds.) By generating more OH radicals, the performance is improved by about 70% or more compared to ozone-only water treatment. In addition, the filling of ozone and granular catalysts solves the problems of commercialization according to the irradiation distance of UV and recovery of TiO ₂ , and it does not add artificial compounds (for example, hydrogen peroxide), thereby greatly reducing the processing cost. It is convenient, efficient, and convenient for field application. In addition, by controlling the amount of current through the electrode of the electrolysis device, the amount of OH radicals can be controlled at the same time.

Ultimately, the present invention has the advantage that it can be applied to a large amount of water treatment, less sludge generation, occupy a small installation area of the treatment device, and also to apply the present invention by utilizing the existing treatment facility Therefore, it can be applied to various water production and various wastewater treatment such as advanced water treatment facility, simple water supply, power generation water, effluent from sewage terminal treatment plant, chlorine organic wastewater, dyeing wastewater, and non-degradable toxic wastewater. Therefore, the present invention can play a role in environmental conservation, and can provide an advantage of activating the global environmental conservation industry.

Claims (7)

A non-degradable waste solution comprising an electrode including a cathode and an anode, a power supply for supplying current to the electrode, an electrolysis tank for treating wastewater, a semiconductor catalyst filled in the electrolysis tank, and an ozone generator for supplying ozone to the electrolysis tank. In the ozone-electrolysis / semiconductor catalyst complex for treatment, A diffusion stone installed at the bottom of the electrolysis tank to subdivide ozone bubbles to maximize contact between ozone and waste water; A tray filled with the semiconductor catalyst and a multi-stage catalyst support structure in which the trays are stacked in multiple layers; A cathode and an anode installed at each stage into which the trays filled with the semiconductor catalyst are inserted; An equalization space that facilitates mixing of the ozone and the wastewater and is present in the upper portion of the semiconductor catalyst layer filled in each tray; A circulating system which allows oxidatively treated waste water to be partially recycled to the bottom of the reactor as needed; And The uppermost layer of the multi-stage catalyst support structure is characterized in that the activated carbon is filled in the basket-type mesh network, ozone-electrolysis / semiconductor catalyst composite device for the treatment of difficult-decomposable waste liquid. 2. The apparatus of claim 1, wherein the semiconductor catalyst is TiO ₂ or ZnO. The apparatus of claim 1, wherein the anode and cathode of the electrode are iridium (Ir) coating on titanium (TiO ₂ ). 2. An apparatus according to claim 1, wherein the anode of said electrode is stainless. The apparatus of claim 1, wherein the cathode of the electrode is a platinum or TiO ₂ coated electrode. A granular semiconductor catalyst layer having an integrated structure to be easily attached and detached from the multi-stage reaction tank (500). A method of treating a hardly degradable waste liquid using the apparatus according to any one of claims 1 to 5, Injecting wastewater into a multi-stage reactor; Mixing the injected waste water with the multi-layer and the activated carbon filled with the semiconductor catalyst as closely as possible; Supplying power to each cathode and anode of the multilayer; Mixing ozone generated by generating ozone in the ozone generator with the wastewater injected into the multi-layer reactor through the ozone diffusion stone; The charged semiconductor catalyst is in contact with an electrode of an electrolysis device installed on the side of the wastewater treatment reactor, and electrons are excited in the ground state (base state) to be in the conduction band; Dissolving ozone at each stage of the multi-stage reactor configured in the multi-stage reactor in contact with the electrode and the charged semiconductor catalyst to receive electrons from the electrodes and convert them into ozonide (O ^- ₃ ); And ozonide rapidly produces HO ₃ , which decomposes into OH radicals and oxygen; Method for treating a hardly degradable waste liquid comprising a.

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