KR102052039B1 - Apparatus for purifying water based on electro-peroxone reaction - Google Patents

Abstract

An electro-peroxone reaction based water treatment apparatus is provided. An electro-peroxone reaction-based water treatment apparatus according to an embodiment of the present invention includes a reactor for electro-peroxone reaction of the treated water; An electrolysis unit including a DC power supply for supplying DC power to at least one pair of electrodes and an electrode provided inside the reactor, and electrolytically treating the treated water to generate hydrogen peroxide; An ozone generator for generating ozone gas; And a mixing unit for mixing the treated water of the reaction tank with the generated ozone gas and supplying the ozone gas and the hydrogen peroxide between the pair of electrodes to allow peroxone reaction.

Description

Apparatus for purifying water based on electro-peroxone reaction

The present invention relates to a numerical device for removing contaminants present in water, and more particularly, to an electro-peroxone reaction-based water treatment device for removing contaminants in water by generating OH radicals by reaction between hydrogen peroxide and ozone gas. will be.

Oxidation method of oxidizing contaminants in water is a method of treating using high oxidizing materials such as chlorine and ozone, and is used in water treatment and wastewater treatment.

Here, the chlorine treatment method is mainly used for microbial disinfection in the water treatment process. Chlorine can also cause damage to aquatic organisms in discharged water during sewage treatment.

In the case of ozone treatment, it is excellent in oxidizing power and is used for advanced treatment in dyeing wastewater color removal or water purification treatment process. However, ozone is highly oxidizing but selectively reacts with organics, so some hardly decomposable substances do not completely mineralize with water and carbon dioxide, and produce reaction byproducts such as aldehydes and bromates. There is also a need for an ozone treatment process to treat unreacted ozone.

In order to make up for the disadvantages of the existing oxidation method, researches using advanced oxidation processes (AOPs) that generate OH radicals to decompose pollutants in water are being conducted. Here, OH radicals generated in the advanced oxidation process are much stronger oxidants than chlorine and chlorine dioxide, and they are intermediately produced when the pollutants are decomposed because they are non-selectively oxidized regardless of the kind of substance to be decomposed. Substances can also be completely decomposed to reduce the potential adverse effects of aquatic ecosystems more efficiently than ozone.

Such advanced oxidation processes include UV / TiO ₂ photocatalyst process using ultraviolet light and photocatalyst to generate OH radicals, UV / H ₂ O ₂ , UV / O ₃ process irradiating ultraviolet light to oxidant, and using iron ions. O ₃ / Fe ^{2 +} , H ₂ O ₂ / Fe ^{2 +} process, and peroxone (O ₃ / H ₂ O ₂ ) process for reacting ozone and hydrogen peroxide. All of these processes are processes for producing OH radicals, and the treatment performance and economical efficiency vary depending on the amount of chemical injection and the amount of UV irradiation, and each process has advantages and disadvantages.

Here, the peroxone process is a method of decomposing organic pollutants by reacting ozone with hydrogen peroxide to generate OH radicals having strong oxidation power, and thus generating OH radicals by reaction of ozone itself and reaction between ozone and hydrogen peroxide. There is an advantage that can reduce the ozone treatment device or reduce the ozone usage.

Meanwhile, according to a report comparing the performance of ozone oxidation and peroxone oxidation through the ibuprofen decomposition experiment of the pharmaceutical substance, ibuprofen was degraded by 40% to 77% during the reaction time by ozone oxidation, but by peroxone oxidation The decomposition resulted in 78-90% degradation of the peroxone oxidation. In particular, it was reported that the secondary reaction rate constant OH. (7.4 × 10 ⁹ M ⁻¹ · S ^{− 1} ) showed a faster reaction rate constant than ozone (9.6 ± 1.0 M ⁻¹ · S ⁻¹ ). As such, the peroxone process may improve the decomposition efficiency of pollutants than the conventional ozone oxidation process.

However, the conventional peroxone process of generating OH radicals using hydrogen peroxide and ozone is a method of supplying both hydrogen peroxide from the outside. At this time, unlike ozone generated through the ozone generator in the field, hydrogen peroxide is supplied separately. Here, hydrogen peroxide has high reactivity with other substances, and thus has many risk factors in handling such as transportation and storage. Therefore, there is a need for a method of improving the decomposition efficiency of materials while supplying hydrogen peroxide stably.

In addition, the conventional peroxone process simply mixes hydrogen peroxide and ozone, and ozone generated in the ozone generator is introduced into the reactor in the form of a gas. At this time, since ozone dissolution rate in water is not high, the generated ozone is not used in the reaction and is discharged to the gas phase. There is a need for an ozone treatment apparatus for treating unreacted ozone in order to prevent the release of ozone into the atmosphere due to low concentrations of the resulting OH radicals.

KR 2014-0057463 A

In order to solve the problems of the prior art as described above, an embodiment of the present invention is an electro-electric generation that can stably perform water treatment by generating electrolyzed treated water without supplying hydrogen peroxide, which requires attention to handling. To provide a peroxone reaction-based water treatment device.

In addition, the present invention is an electro-peroxone reaction that mixes ozone gas generated in the ozone generator with the treated water of the reaction tank and sprays it back into the reaction tank through a nozzle to increase the dissolved rate of ozone gas to improve the treatment efficiency of pollutants. An object of the present invention is to provide a water treatment system.

In another aspect, the present invention is to provide an electro-peroxone reaction-based water treatment device that can further enhance the treatment efficiency of pollutants by promoting the peroxone reaction using a variety of oxidants generated during the electrolysis of the treated water.

According to an aspect of the present invention for solving the above problems, a reactor for the electro-peroxone reaction of the treated water; An electrolysis unit including at least one pair of electrodes provided in the reactor and a DC power supply for supplying DC power to the electrodes, the electrolysis unit generating hydrogen peroxide by electrolyzing the treated water; An ozone generator for generating ozone gas; And a mixing unit for mixing the treated water of the reactor with the generated ozone gas and supplying the ozone gas and the hydrogen peroxide between the pair of electrodes so as to peroxone the reaction. The electro-peroxone reaction-based water treatment apparatus includes: Is provided.

In one embodiment, the electrodes may be provided in a plurality of pairs spaced apart at regular intervals.

In one embodiment, the interval between the electrode disposed at the outermost of the at least one pair of electrodes and the reaction tank may be 5 to 15 times larger than the interval between the pair of electrodes.

In one embodiment, the electrolyte for electrolysis comprises NaCl, and the electrodes are superoxide radical (· O ₂ ^-), hydroperoxides oxy radicals (· OOH), or free chlorine (free Cl), ClO _2, OCl ^- it can be oxidized to the treatment to generate a chlorine-based oxidizing agent, including any one of the.

In one embodiment, the electrode comprises an anode comprising any one of a dimensionally stable anode (DSA), stainless steel, and a boron doped diamond (BDD) electrode; And a cathode made of any one of graphite, carbon felt, activated carbon fiber (ACF), DSA, stainless steel, and BDD electrodes.

In one embodiment, the mixing unit circulating pump for discharging the treated water in the reaction tank to the outside; A mixer for mixing the ozone gas generated from the ozone generator and the discharged treated water; And a mixed water discharge pipe for supplying the mixed mixed water between the pair of electrodes in the reaction tank.

In one embodiment, the reactor may include a partition wall is provided on the side to which the circulation pump is connected to block bubbles in the treated water from entering the circulation pump side.

In one embodiment, the mixing unit may further include a nozzle provided at one end of the mixed water discharge pipe and disposed between the pair of electrodes.

In one embodiment, the mixer may be a T-shaped fitting or aspirator.

In one embodiment, the mixing ratio of the ozone gas and the treated water may be 25 to 200% of the flow rate of the treated water relative to the ozone gas flow rate.

The electro-peroxone reaction-based water treatment device according to an embodiment of the present invention can lower the risk of handling hydrogen peroxide by directly generating hydrogen peroxide, which is one of the essential elements of the peroxone process, in the electrolysis reaction, thereby ensuring the stability of the water treatment. At the same time, there is no need to transport and supply hydrogen peroxide separately, thereby improving water treatment efficiency.

In addition, the present invention by mixing the ozone gas generated in the ozone generator with the treated water to dissolve the ozone gas first, and then sprayed into the water in the reactor through the nozzle to induce the secondary dissolved ozone gas, thereby increasing the concentration of OH radicals This can improve the treatment efficiency of contaminants and reduce the cost of ozone treatment.

In addition, the present invention can further improve the treatment efficiency of pollutants by using the radical and chlorine-based oxidant generated in the electrolysis reaction in the pollutant removal reaction.

1 is a schematic view showing an electro-peroxone reaction-based water treatment device according to an embodiment of the present invention,
Figure 2 is a schematic diagram for explaining the principle of generating OH radicals according to the electro- peroxone reaction in the electro- peroxone reaction-based water treatment apparatus according to an embodiment of the present invention,
3 is a schematic view for explaining the principle of generating OH radicals when a mixture of ozone and treated water is injected from the nozzle in the electro-peroxone reaction-based water treatment device according to an embodiment of the present invention,
4 is a graph showing OH radical exposure according to electrolysis, ozone, and electro-peroxone reactions,
5 is a graph showing the change of acetaminophen concentration according to the electrolysis, ozone, and electro-peroxone reaction,
FIG. 6 is a graph depicting changes in TOC concentration showing final decomposition of acetaminophen upon electrolysis, ozone, and electro-peroxone reactions.
FIG. 7 is a graph showing the exposure amount of OH radicals when ozone gas is introduced into the diffuser and when ozone gas is introduced through treatment water mixing and nozzle injection.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like elements throughout the specification.

Hereinafter, an electro-peroxone reaction-based water treatment apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 is a schematic view showing an electro-peroxone reaction-based water treatment device according to an embodiment of the present invention.

Referring to FIG. 1, the electro-peroxone reaction-based water treatment device 100 according to an embodiment of the present invention includes a reactor 110, an electrolysis unit 121 to 123, an ozone generator 130, and a mixing unit 141. 145) and the ozone mixed water reservoir 150.

Here, the electro-peroxone reaction-based water treatment device 100 is a water treatment device using an advanced oxidation process (AOP) that can effectively remove contaminants in the water present in the constant raw water, sewage / waste water, ozone (O ₃ ) In the peroxone process of forming OH radicals (OH ·) using a reaction of hydrogen peroxide (H ₂ O ₂ ), hydrogen peroxide is produced by electrolysis to ensure stability of water treatment.

In addition, the electro-peroxone reaction-based water treatment apparatus 100 mixes ozone gas with the treated water discharged from the inside of the reaction tank 110 to dissolve the primary, and then injects into the reaction tank 110 to induce the secondary dissolution. It is possible to promote the reaction between ozone and hydrogen peroxide by increasing the dissolution rate. As a result, by increasing the production of OH radicals, it is possible to improve the removal efficiency of various contaminants such as odors, volatile organic compounds and microorganisms, as well as organic contaminants present in water.

In addition, the electro-peroxone reaction-based water treatment device 100 may further improve the treatment efficiency of contaminants by using radical or chlorine-based oxidants generated by electrolysis in the contaminant removal reaction.

The reactor 110 is for electro-peroxone reaction of the target treated water to remove contaminants, and the treated water is introduced into the lower inlet 112 and the treated water can be discharged through the upper treated water outlet 151. have.

The reactor 110 may be provided with a partition wall 111 on the pipe side to which the circulation pump 141 is to be described later. Here, the reaction tank 110 circulates the treated water up and down, and together with the bubbles such as oxygen and ozone contained in the treated water. In this case, the partition wall 111 may block air bubbles contained in the treated water from being introduced into the circulation pump 141.

The partition wall 111 may extend from a portion where the circulation pump 141 is connected to the reaction tank 110 to a portion where the mixed water discharge pipe 144 is installed below the reaction tank 110.

The electrolysis parts 121 to 123 are for generating hydrogen peroxide by electrolyzing the treated water in the reaction tank 110, and may include at least one pair of electrodes 121 and 122 and a DC power supply 123.

The electrodes 121 and 122 may be provided in the reaction tank 110, and the anode 121 and the cathode 122 may be paired to face each other at a predetermined interval. Here, the anode 121 may be formed of any one of a dimensionally stable anode (DSA), stainless steel, and a boron doped diamond (BDD) electrode. The cathode 122 may be formed of any one of carbon-derived electrodes such as graphite, carbon felt, and ACF, and DSA, stainless steel, and BDD electrodes.

In addition, the electrodes 121 and 122 may be provided in a plurality of pairs spaced at regular intervals according to the amount of treated water, and thus may be configured in a sequential multistage arrangement. In this case, the distance between the electrodes 121 and 122 and the reaction tank 110 may be greater than the distance between the electrodes 121 and 122 so that the flow of the treated water in the reaction tank 110 is smooth. Preferably, the interval between the electrode disposed at the outermost of the electrodes 121 and 122 and the reaction tank 110 may be 5 to 15 times larger than the interval between the pair of electrodes 121 and 122.

For example, the distance between the pair of electrodes 121 and 122 may be 1 cm to 3 cm. In addition, the interval between the cathode 122 disposed at the leftmost side of the reactor 110 and the reactor 110 and the interval between the anode 121 disposed at the rightmost side of the reactor 110 and the reactor 110 are 5. Cm to 15 cm.

The DC power supply 123 is provided outside the reactor 110 and may supply DC power to the electrodes 121 and 122 through a power line.

The ozone generator 130 may receive ozone (O ₂ ) from the outside to generate ozone gas (O ₃ ). Here, the ozone generator 130 may be connected to the mixer 143 through the ozone gas discharge pipe 131.

The mixing units 141 to 145 may mix the treated water in the reaction tank 110 with ozone gas generated from the ozone generator 130 and supply the same between the pair of electrodes 121 and 122. Here, the ozone gas supplied by the mixing units 141 to 145 may react with hydrogen peroxide generated by electrolysis between the pair of electrodes 121 and 122 and peroxone reaction.

The mixing unit 141 to 145 may include a circulation pump 141, a circulating water inlet pipe 142, a mixer 143, a mixed water discharge pipe 144, and a nozzle 145.

The circulation pump 141 may discharge the treated water from the reaction tank 110 through the pipe. At this time, the circulation pump 141 may be connected to the upper side of the reaction tank (110). Here, since the treated water in the reaction tank is circulated by the circulation pump 141, the circulating water may be understood as the same as the treated water in the reaction tank 110 in the following description.

The circulation water inlet pipe 142 may be disposed between the circulation pump 141 and the mixer 143. The circulating water inlet pipe 142 may supply the circulating water discharged from the reaction tank 110 to the mixer 143 by the circulating pump 141.

In the mixer 143, circulating water may be introduced from the circulation pump 141 and ozone gas may be introduced from the ozone generator 130 to mix them. Here, the mixer 143 may include an inlet through which circulating water and ozone gas are introduced into both sides, and an outlet through mixing and discharging the circulating water and ozone gas into the other side. In one example, the mixer 143 may be a T-shaped fitting or aspirator.

In addition, the mixer 143 may constantly adjust the mixing ratio of ozone gas and circulating water. For example, the mixing ratio of the ozone gas and the circulating water may be 25 to 200% of the flow rate of the circulating water with respect to the ozone gas flow rate.

The mixed water discharge pipe 144 may extend from the mixer 143 to the electrodes 121 and 122 in the reaction tank 110. That is, one side of the mixed water discharge pipe 144 may be connected to the mixer 143, and the other side may be disposed between the pair of electrodes 121 and 122 disposed far away from home in the reactor 110.

The nozzle 145 may be provided at one end of the mixed water discharge pipe 144. Here, the nozzle 145 may be disposed between the pair of electrodes 121 and 122. As a result, the nozzle 145 may supply the mixed water mixed with the ozone gas and the circulating water supplied from the mixed water discharge pipe 144 between the pair of electrodes 121 and 122 in the reaction tank 110. The nozzle 145 may be a nozzle for water injection.

The ozone mixed water reservoir 150 may be provided at one side of the reaction tank 110 and communicate with the reaction tank 110. The ozone mixed water reservoir 150 is introduced into the unreacted ozone gas remaining after reacting with hydrogen peroxide in the reaction tank 110, the ozone generator 130, and flowing into the oxygen and the reaction tank 110 remaining after the ozone gas generation. The ozone mixed water mixed with the treated water can be stored. Here, the ozone mixed water reservoir 150 may discharge the treated water decontaminated through the treated water outlet 151.

In addition, the ozone mixed water reservoir 150 may be provided with an ozone removing device 152 on one side. The ozone removal apparatus 152 may be discharged to the outside through the ozone removal gas outlet 153 by removing the ozone gas and oxygen contained in the mixed ozone mixed water.

Figure 2 is a schematic diagram for explaining the principle of generating OH radicals according to the electro- peroxone reaction in the electro- peroxone reaction-based water treatment apparatus according to an embodiment of the present invention.

When the treated water is electrolyzed in the reactor 110, oxygen, hydrogen ions, and electrons are generated at the anode 121 as shown in Equation 1, and oxygen, hydrogen ions, and electrons are generated at the cathode 122 as shown in Equation 2. Hydrogen peroxide is produced through the reduction process.

At this time, the ozone gas generated by the ozone generator 130 and the ozone generator 130 are supplied to the unreacted oxygen and discharged into the reaction tank 110 through a gas discharge device such as the diffuser 132.

Hydrogen peroxide generated in the electrolysis reaction as described above generates OH radicals through ozone gas discharged into the treated water and a peroxone reaction as in Equation 3.

As such, the OH radicals generated by the peroxone reaction react with and oxidize organic pollutants in the treated water.

The present invention, unlike the conventional peroxone process of supplying hydrogen peroxide externally, can directly generate hydrogen peroxide in the reaction tank 110 by an electrolysis reaction. At this time, small amounts of radicals such as OH radicals, superoxide radicals (· O ₂ ⁻ ), hydroperoxy radicals (· OOH), and the like are generated on the surfaces of the electrodes 121 and 122, and ozone gas is also generated by direct electrolysis of the treated water. .

In addition, when an electrolyte such as NaCl is used, chlorine-based oxidants such as free chlorine (free Cl), ClO ₂ , and OCl ⁻ may be generated. Since the additionally generated oxidant can be used for the pollutant treatment, the present invention can improve the removal efficiency of the pollutant rather than using only hydrogen peroxide.

3 is a schematic diagram for explaining a principle of generating OH radicals when a mixture of ozone and treated water is injected from a nozzle in an electro-peroxone reaction-based water treatment device according to an embodiment of the present invention.

Since the Henry's constant is 4.6 × 10 ³ in water with a water temperature of 20 ° C, only about 10% of the nonpolar organic solvent is dissolved. When the solubility of ozone is represented by the distribution coefficient represented by Equation 4, the distribution coefficient D of ozone in water at 25 ° C. is reported as 0.2.

As can be seen from this, in order to increase the production concentration of OH radicals, the dissolved rate of ozone discharged from the ozone generator 130 to the treated water must be increased.

To this end, the present invention instead of directly supplying the ozone gas generated in the ozone generator 130 to the reaction tank 110, by using the circulation pump 141 to generate the treated water in the reaction tank 110 in the ozone generator 130 Mixing with the ozone gas may be injected into the reaction tank (110).

More specifically, the mixer 143 may mix the treated water and ozone gas to generate the gas-liquid mixed water G1. Here, the circulating water and the ozone gas may be dissolved first. At this time, since the gas-liquid mixed water G1 is mixed in a narrow flow path, the dissolved rate of ozone gas may be increased.

Next, as the gas-liquid mixed water G1 is sprayed into the water through the nozzle 145, the ozone gas not yet dissolved may be secondary dissolved. The secondary dissolved ozone gas may react with hydrogen peroxide generated during electrolysis to generate OH radicals. Thereby, compared with the case where the ozone gas is directly discharged to the treated water, the production concentration of OH radicals can be improved.

Here, the ozone gas injected into the water is mixed by the pressure by the circulation pump 141 and the ozone gas discharge pressure of the ozone generator 130, and discharged into the water through the nozzle 145 having a small diameter, so In the same peroxone process, the size of the gas is smaller than that of the ozone gas discharged from the diffuser 132, thereby increasing the dissolved rate of the ozone gas.

As a result, the present invention produces OH radicals by using an electro-peroxone reaction which generates hydrogen peroxide in an electrolysis reaction and reacts with ozone gas instead of the conventional peroxone reaction in which hydrogen peroxide and ozone are separately supplied to generate OH radicals. At the same time, radicals such as superoxide radicals (· O ₂ ⁻ ), hydroperoxy radicals (· OOH), and chlorine-based oxidizing agents such as free chlorine (free Cl), ClO ₂ , and OCl ⁻ that are not produced in conventional drug-added peroxone reactions. It can produce and use for oxidation reaction.

In addition, the present invention does not directly discharge the ozone gas having a low dissolution rate into the reaction tank 110, but pre-mixed with the treated water of the reaction tank 110, the first dissolved and then through the nozzle using the pressure of the circulation pump and the ozone generator By secondary dissolving by spraying into the reactor, the secondary dissolved ozone gas reacts with hydrogen peroxide generated in electrolysis to increase the amount of OH radicals produced, thereby improving the oxidizing power and thus improving the removal efficiency of contaminants.

Referring back to Figure 1 will be described the operation of the electro- peroxone reaction-based water treatment apparatus 100 according to an embodiment of the present invention.

First, the treated water containing the contaminant is introduced into the inlet 112 of the reaction tank 110. The introduced treated water moves upward and encounters the gas-liquid mixed water G1 which is a mixture of ozone gas and treated water sprayed from the nozzle 145 between the anode 121 and the cathode 122 so that ozone is re-dissolved. Can be.

At this time, hydrogen peroxide generated by the electrolysis of the anode 121 and the cathode 122 may be generated. Here, the dissolved ozone may react with the produced hydrogen peroxide to produce OH radicals.

The resulting OH radicals mineralize the organic pollutants contained in the treated water with CO ₂ and H ₂ O. At this time, the gas-liquid mixed water G1 injected by the nozzle 145 reacts while being ejected upward, and generates a downward liquid flow S1 at the left and right sides of the reaction tank 110 at the upper portion of the reaction tank 110. It flows down 110.

The treated water moved downward forms an upward flow by the upward flow of the liquid S2 by the inlet 112 and the jet flow of the gas-liquid mixed water G1 at the nozzle 145, and the upper portion of the reactor 110. The treated water rises again to form a downward liquid stream S1 and flows downward.

At this time, the circulation pump 141 sends the treated water in the reaction tank 110 to the T-shaped mixer 143 using the circulating water, and the ozone generator 130 sends the generated ozone gas through the ozone gas discharge pipe 131. When sent to the mixer 143, ozone gas is mixed with the circulating water. When the mixed water is sprayed through the nozzle 145 disposed between the anode 121 and the cathode 122 in the reaction tank 110, it reacts with the hydrogen peroxide generated by the electrodes 121 and 122.

As described above, after the organic pollutants contained in the treated water are oxidized by using various oxidants generated by electrolysis in addition to the OH radicals generated by the reaction between hydrogen peroxide and ozone, the treated water is subjected to the ozone mixed water storage tank 150. After passing through the treated water outlet 151, the unreacted ozone gas and oxygen are discharged to the ozone removal gas outlet 153 via the ozone removal device 152.

Hereinafter, with reference to FIGS. 4 to 7, OH radicals are generated using the electro-peroxone reaction-based water treatment device 100, removal of acetaminophen, which is a hardly decomposable pharmaceutical substance, and ozone gas on OH radicals are generated. The experimental results for the improvement of the dissolution rate by mixing will be described.

4 is a graph showing the OH radical exposure according to the electrolysis, ozone, and electro-peroxone reaction.

In general, since OH radicals have very short half-lives and are difficult to measure directly, degradation concentrations were measured using a poorly degradable model material such as p-CBA (para-chloro benzoic acid). In this case, assuming that p-CBA is decomposed by OH radicals, the OH radical concentration may be calculated using the decomposition rate constant of p-CBA.

)은 수학식 5를 재배열한 수학식 6으로 계산하여 측정하였다.Here, the decomposition rate constant of p-CBA is expressed as in Equation 5, OH · generation amount (

) Was calculated by calculating Equation 5 by rearranging Equation 5.

Here, when the decomposition rate of p-CBA is large, it can be seen that the amount of OH radicals is large.

P-CBA decomposition experiments were performed in electrolysis alone, ozone alone, and electro-peroxone processes using p-CBA, a model material for confirming the generation of OH radicals. At this time, the positive electrode 121 was a DSA, the negative electrode was used carbon felt, the size of the electrode was 25 cm2 (5cm × 5cm), the distance between the electrodes 5mm, the electrolyte was used 0.05M Na ₂ SO ₄ , A current of 600 mA was applied to the electrode. Ozone was generated by supplying oxygen (O ₂ ,> 90%) to the ozone generator 130, and the flow rate of ozone gas flowing into the reactor 110 by supplying ozone using the acid pipe 132 is 0.25 L / min. Adjusted to. Here, the power of the ozone generator 130 was 140 W, and the concentration of ozone generated was 48.4 mg / L. The p-CBA concentration used for the experiment was 10 mg / L.

Under these conditions, the exposure of OH radicals generated during the decomposition of p-CBA in the electrolysis alone process without ozone, the ozone alone process without the ozone, and without electrolysis, and the electro-peroxone process is determined. Measured.

As shown in FIG. 4, the exposure of the electro-peroxone process is 0.626 × 10 ⁻⁹ M · S, which is 0.155 × 10 ⁻⁹ M · S, which is the exposure by the electrolysis alone process, and 0.031, which is the exposure by the ozone alone process. Values higher than × 10 ⁻⁹ M · S. In each process, the amount of OH radicals increased linearly with the reaction time (R ² = 0.994 to 0.999), indicating that the pseudo-steady concentration of OH radicals persisted during the reaction time of the process. Indicates.

As a result of calculating the pseudo-steady-state concentration of OH radicals using Equation 6, the electro-peroxone process was 0.417 × 10 ^-9 mM, the electrolysis was 0.086 × 10 ^-9 mM, and the ozone was 0.017 × 10 ^-9 mM. Appeared. This means that the electro-peroxone process produces significantly higher OH radical concentrations than other single oxidation processes, resulting in a synergistic effect with higher OH radical concentrations occurring than the arithmetic sum of a single process.

5 is a graph showing the change of acetaminophen concentration according to the electrolysis, ozone, and electro-peroxone reaction.

In the above electrolysis alone, ozone alone, electro-peroxone process, the ratio (C / C ₀ ) of the initial concentration (C ₀ ) and the concentration (C) after the reaction for the decomposition of acetaminophen, a hardly decomposable drug was measured. Here, C / C ₀ is 1 at the start of the experiment and C / C ₀ is 0 when acetaminophen is 100% decomposed.

At this time, the concentration of acetaminophen was fixed at 10 mg / L, and experiments for the electrolysis, ozone, and electro-peroxone reaction were performed under the same conditions as the above-described p-CBA decomposition test.

As can be seen from Figure 5, the ratio of the reaction time to the initial concentration of acetaminophen in the electrolysis, ozone alone process during the reaction time of 10 minutes was 0.663, 0.147 respectively. In contrast, the electro-peroxone process was completely decomposed to zero for a reaction time of 6 minutes.

Here, the electrolysis process is a process in which the oxidant generated by the direct oxidation effect of the electrode surface and the electrochemical reaction decomposes the material, and the C / C ₀ ratio indicating the lowest acetaminophen decomposition was high. This means that direct oxidation at the electrode surface and the resulting oxidant did not efficiently decompose acetaminophen. In addition, since the amount of generated OH radicals is small, the decomposition efficiency is judged to be low.

For the ozone process, the C / C ₀ ratio of acetaminophen for 0.1 min was found to be 0.147, with about 85% being degraded. The electro-peroxone process, which combines the electrolysis and ozone processes, removes 100% in 6 minutes and removes acetaminophen more quickly than in the single process. This is because the material decomposition efficiency is increased by synergistic effects due to the coupling between processes.

In order to quantitatively evaluate the synergistic effect of the electro-peroxone complex process, the pseudo first order rate constant was obtained and the enhancement coefficient was calculated according to Equation 7.

,

,

는 전기분해, 오존, 전기-페록손 공정 각각에 대한 의사 1차 반응속도상수를 나타낸다. here,

,

,

Represents the pseudo-first-order rate constants for each of the electrolysis, ozone, and electro-peroxone processes.

Table 1 shows the pseudo-first order rate constants for the acetaminophen degradation in the electrolysis, ozone and electro-peroxone processes and the improvement coefficients of the electro-peroxone process.

fair K _app (min ^-1 ) Improvement factor Electrolysis 0.041 - ozone 0.192 - Electric-Peroxone 0.429 1.84

As shown in Table 1, the electro-peroxone process showed 1.84 times improvement over the other two processes.

As described above, the reason why the electro-peroxone process shows faster decomposition efficiency than other single oxidation processes is that the decomposition efficiency is increased because it generates more OH radicals. You can check it.

FIG. 6 is a graph depicting changes in TOC concentration showing final degradation of acetaminophen upon electrolysis, ozone, and electro-peroxone reactions.

In the above electrolysis alone, ozone alone, and electro-peroxone processes, the ratio of initial concentration (C ₀ ) and concentration after reaction (C) to total organic carbon (TOC) decomposition indicating inorganicization of acetaminophen (C / C ₀ ) was measured. Here, C / C ₀ is 1 at the start of the experiment, and C / C ₀ is 0 when complete mineralization is achieved by removing 100% of the TOC of acetaminophen.

At this time, the concentration of acetaminophen was fixed at 10 mg / L, and the experiments for the electrolysis, ozone, and electro-peroxone reaction were carried out under the same conditions as the p-CBA decomposition test described above, and TOC was measured.

As can be seen from FIG. 6, electrolysis and ozone decomposed 41.2% and 42.2%, respectively, during the reaction time of 180 minutes. On the other hand, the electro-peroxone reaction showed 81.9% degradation at 40 minutes and 100% degradation at 60 minutes. The electro-peroxone process generates more OH radicals than other oxidation processes, and OH radicals have been shown to rapidly decompose acetaminophen and intermediates into CO ₂ and H ₂ O through non-selective oxidation reactions.

In the case of ozone, acetaminophen decomposition was higher than that of electrolysis, but the TOC removal rate was similar to that of electrolysis.

FIG. 7 is a graph showing the exposure amount of OH radicals when ozone gas is introduced into the diffuser and when ozone gas is introduced through treatment water mixing and nozzle injection.

Under conditions that the ozone gas is introduced into the reaction tank 110 into the diffuser 132 as shown in FIG. 2, and the first mixture is mixed in the mixer 143 as illustrated in FIG. The exposure of OH radicals was compared. Here, the OH radical exposures generated during the degradation of p-CBA were compared.

The electro-peroxone reaction using the diffuser 132 introduced the ozone gas generated in the ozone generator 130 into the reactor at a rate of 0.25 L / min. The electro-peroxone reaction using the mixer 143 and the nozzle 145 introduces ozone gas into the mixer 143 at a rate of 0.25 L / min, and uses a treated water in the reaction tank 110 as a circulating pump. Through 141, the mixture was introduced into the mixer 143 at a flow rate of 0.13 L / min, followed by primary mixing, and then sprayed in the reactor 110 using the nozzle 145. Conditions other than the discharge and injection of ozone gas were the same conditions as the p-CBA decomposition test described above.

As can be seen from FIG. 7, the OH radical exposure of the electro-peroxone process using the diffuser 132 is 0.626 × 10 ⁻⁹ M · S, and ozone and circulating water are first mixed in the mixer 143. The OH radical exposure of the electro-peroxone step of secondary injection with the nozzle 145 is 0.866 × 10 ⁻⁹ M · S. That is, since the OH radical exposure amount by the mixer 143 and the nozzle 145 is 38.3% higher than the OH radical exposure amount by the diffuser 132, the generation efficiency of OH radicals due to the mixing and injection of ozone gas is improved. Appeared.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments set forth herein, and those skilled in the art who understand the spirit of the present invention may add components within the same scope. Other embodiments may be easily proposed by changing, deleting, adding, etc., but this will also fall within the spirit of the present invention.

100: electro-peroxone reaction based water treatment device
110: reactor 111: partition wall
112 inlet 121 anode
122: negative electrode 123: DC power supply
130: ozone generator 131: ozone gas discharge pipe
132: diffuser 141: circulation pump
142: circulating water inlet pipe 143: mixer
144: mixed water discharge pipe 145: nozzle
150: ozone mixed water reservoir 151: treated water outlet
152: ozone removal unit 153: ozone removal gas outlet
G1: Mixed Water G2: Mixed Gas
S1: downward liquid flow S2: upward liquid flow

Claims (10)

A reactor for electro-peroxone reaction of the treated water;
An electrolysis unit including at least one pair of electrodes provided in the reactor and a DC power supply for supplying DC power to the electrodes, the electrolysis unit generating hydrogen peroxide by electrolyzing the treated water;
An ozone generator for generating ozone gas; And
A mixing unit for mixing the treated water of the reactor with the generated ozone gas and supplying the ozone gas and the hydrogen peroxide between the pair of electrodes to peroxone the reaction;
Including,
The electrode is a pair of the anode and the electrode are arranged facing each other at a predetermined interval and a plurality of pairs are configured in a multi-stage array,
The mixing unit,
A circulation pump connected to the upper side of the reaction tank to discharge the treated water in the reaction tank to the outside as circulating water;
A mixer for generating a gas-liquid mixed water by mixing the introduced ozone gas with the circulating water by introducing the circulating water from the ozone gas generated from the ozone generator and the circulating pump;
A mixed water discharge pipe extending from the mixer to the electrode in the reaction tank and supplying the gas-liquid mixed water between the pair of electrodes in the reaction tank; And
And a water spray nozzle disposed at one end of the mixed water discharge pipe and disposed between the pair of electrodes and spraying the gas-liquid mixed water to the reactor.
The reactor is formed extending from the upper side to the lower side to which the circulation pump is connected, the electro-peroxone reaction-based water treatment device comprising a partition wall to block the bubbles in the treated water from entering the circulation pump side. delete The method of claim 1,
An electro-peroxone reaction-based water treatment apparatus, wherein a distance between the electrode disposed at the outermost of the at least one pair of electrodes and the reactor is 5 to 15 times larger than a distance between the pair of electrodes. The method of claim 1,
The electrolyte for electrolysis comprises NaCl,
The electrode superoxide radical (· O ₂ ^-), hydroperoxides oxy radicals (· OOH), or free chlorine (free Cl), ClO _2, and OCl ^- of the number of the processing to generate a chlorine-based oxidizing agent containing any An electro-peroxone reaction based water treatment apparatus which oxidizes. The method of claim 1,
The electrode,
An anode made of any one of a dimensionally stable anode (DSA), stainless steel, and a boron doped diamond (BDD) electrode; And
An electro-peroxone reaction based water treatment device comprising a cathode made of graphite, carbon felt, activated carbon fiber (ACF), DSA, stainless steel, and BDD electrode. delete delete delete The method of claim 1,
And the mixer is a T-shaped fitting or aspirator. The method of claim 1,
The mixing ratio of the ozone gas and the circulating water is an electro-peroxone reaction-based water treatment device, the flow rate of the circulating water is 25 ~ 200% with respect to the ozone gas flow rate.

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