WO2004069754A1

WO2004069754A1 - Method of decomposing hardly decomposable organic compound and apparatus therefor

Info

Publication number: WO2004069754A1
Application number: PCT/JP2004/001382
Authority: WO
Inventors: Tsunehisa Araiso
Original assignee: Nt Nitto Sangyo Co., Ltd; Urban Environment Consultant Co., Ltd.; Alpha Planning Limited
Priority date: 2003-02-10
Filing date: 2004-02-10
Publication date: 2004-08-19
Also published as: JP3990993B2; JP2004261638A

Abstract

A method of decomposing hardly decomposable organic compounds, in which the decomposition of hardly decomposable organic compounds being present in not only liquids but also soils is accelerated through activation of ozone and accordingly, hardly decomposable organic compounds being present in liquids and soils at low concentrations can be rapidly decomposed; and an apparatus therefor. In particular, ozone is injected in treatment systems, such as liquids and soils, wherein hardly decomposable organic compounds are present, and tourmaline powder is mixed thereinto. An action to cause this tourmaline powder to undergo charge separation on crystals is applied, thereby activating ozone. Thus, the treatment of hardly decomposable organic compounds is accelerated.

Description

Description Method and apparatus for decomposing hard-to-decompose organic compounds

The present invention relates to a method and an apparatus for decomposing a hardly decomposable organic compound, and in particular, to a technology for decomposing a hardly decomposable organic compound using an ozone activating action of tourmaline powder such as dolapite. Background art

Persistent organic compounds such as dioxins and polychlorinated biphenyls (PCB) are discharged into the natural world from waste incinerators, incinerators for industrial waste, various equipment, etc. It is a major social problem because it may be discharged at the same time.

Generally, polychlorinated dibenzoparadioxins (PCDD), polychlorinated dibenzofurans (PCDF), and cobraner polychlorinated biphenyls (cobraner PCB) are called dioxins, which are extremely toxic and have exogenous endocrine secretions. It is known to be a disruptor.

Various techniques for decomposing such dioxins have been proposed, but ozone water obtained by dissolving ozone gas in water is particularly effective in sterilizing, deodorizing, bleaching, etc. due to the strong oxidizing power of ozone. However, ozone gas is self-decomposing into harmless oxygen over time and has no residual properties.

For example, a study reported that 97% of dioxin was degraded 50 hours after injection of ozone by suspending 2,3,7,8-tetraclomouth dibenzoparadioxin in water and carbon tetrachloride. There is, but processing time It has been pointed out that it takes too much time.

Various technologies have been proposed to promote the decomposition treatment with ozone in order to solve such problems. For example, Japanese Patent Application Laid-Open No. 2002-186.850 discloses a method in which a liquid such as wastewater is used. A technology has been proposed that effectively decomposes dioxins contained by using ozone and ultraviolet light in combination. According to this, when ultraviolet rays are irradiated into wastewater containing ozone, extremely reactive hydroxy radicals are formed, so that decomposition of dioxins and the like can be promoted.

However, in the invention described in the above-mentioned patent document, the structure is such that ultraviolet light is irradiated into the wastewater, so that it is effective for decomposing dioxins and the like in the liquid, but is present in the soil. In the case of decomposing dioxins and the like, there is a problem that the effect is reduced because ultraviolet rays cannot be sufficiently irradiated.

The present invention has been made to solve such a problem, and is based on the premise that the present invention is adapted to the decomposition of hardly decomposable organic compounds present not only in a liquid but also in a soil, and to activate ozone. A method for decomposing hard-to-decompose organic compounds that can rapidly decompose hard-to-decompose organic compounds present at low concentrations in liquids and soil, It is intended to provide such a device. Disclosure of the invention

The feature of the method for decomposing a hardly decomposable organic compound according to the present invention is that a system such as a liquid in which a hardly decomposable organic compound is present or a system in which a liquid is contained in soil in which a hardly decomposable organic compound is present is used. Ozone injecting step, injecting tourmaline powder into the processing system, and separating the tourmaline powder mixed in the tourmaline powder mixing step on the crystal. And an electric stone powder charge separation step to add an action.

By adopting such a method, charge separation of tourmaline powder on the crystal activates ozone by strong and polarized charges generated at the crystal axis ends, and furthermore, the surface of the tourmaline powder In this method, a decomposition reaction by activated ozone is caused with high probability by adsorbing a hardly decomposable organic compound, thereby increasing the decomposition efficiency, and promoting decomposition of the hardly decomposable organic compound by both of these decomposition actions.

Further, in the present invention, as the tourmaline powder, it is preferable to use a tourmaline ceramic ground powder obtained by firing natural tourmaline to make it ceramic. As described above, the ceramicization increases the ozone activating effect at the interface of tourmaline powder, increases the amount of active oxygen species in the liquid, and reduces the difficulty of decomposing organic compounds on the surface of tourmaline powder. It is thought that the efficiency of the decomposition reaction of activated ozone is improved by the adsorption action of activated ozone, which further promotes the decomposition of the hardly decomposable organic compound.

Further, in the present invention, it is desirable to use, as tourmaline powder, a dorapite ceramic powder obtained by firing natural doravit. According to this, an inexpensive ozone activating material can be stably obtained, and the facility can be operated with a simple system configuration.

Further, in the tourmaline powder charge separation step in the present invention, the tourmaline powder may be subjected to charge separation on the crystal by applying a voltage to the treatment system. According to this, a strong polarization charge is easily generated at the crystal axis end of tourmaline powder by applying a voltage, thereby activating ozone, and at the same time, adsorbing action of a hardly decomposable organic compound on the surface of tourmaline powder. As a result, the decomposition reaction efficiency can be improved.

Further, the feature of the apparatus for decomposing a hardly decomposable organic compound according to the present invention is that a decomposition reaction tank in which a step of decomposing the hardly decomposable organic compound is performed, And an ozone injection means for injecting ozone into the decomposable organic compound decomposer, comprising: a tourmaline powder mixing means for mixing tourmaline powder into the decomposition reaction tank; The point is that charge separation means for separating charges on the crystal is provided. By adopting such a configuration, a liquid or soil containing a hardly decomposable organic compound is charged into the decomposition reaction tank, and ozone is injected by the ozone injection means, and the liquid in the decomposition reaction tank is injected. Ozone is activated by mixing a predetermined amount of tourmaline powder by means of a tourmaline powder mixing means according to the conditions of soil and soil, etc., and separating the charge on the crystal by the charge separation means. First, the decomposition treatment of the hardly decomposable organic compound is promoted by improving the efficiency of the ozone decomposition reaction by the adsorption of the hardly decomposable organic compound on the surface of tourmaline powder. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic view showing one example of an embodiment of a device for decomposing hardly decomposable organic compounds according to the present invention.

FIG. 2 is an explanatory diagram showing 2,6-dichloro_4_heterophenol which is decomposed in Example 1.

FIG. 3 is a graph showing the experimental results of Comparative Example 1, and is a graph showing the relationship between the wavelength and the absorbance over time after the decomposition treatment.

FIG. 4 is a graph showing the experimental results of Example 1, and is a graph showing the relationship between the wavelength and the absorbance over time after the decomposition treatment.

FIG. 5 is a graph showing experimental results of Example 1 and Comparative Example 1, and is a graph showing a change in relative absorbance with respect to time.

FIG. 6 is a graph showing the experimental results of Comparative Example 2, and is a graph showing the relationship between the wavelength and the absorbance over time after the decomposition treatment. FIG. 7 is a graph showing the experimental results of Example 2, and is a graph showing the relationship between the wavelength and the absorbance over time after the decomposition treatment. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an example of an embodiment of a method for decomposing a hardly decomposable organic compound and an apparatus for performing the method according to the present invention will be described with reference to the drawings.

As a result of intensive studies, the present inventors have found that when ozone is injected into a liquid containing a hardly decomposable organic compound to perform a decomposition treatment, a highly piezoelectric tourmaline powder such as drapite powder is mixed. It has been found that the decomposition processing speed can be remarkably accelerated, especially for the decomposition of low-concentration hard-to-decompose organic compounds.

¾) Achieved fruitful results

The method for decomposing a hardly decomposable organic compound according to the present embodiment mainly uses ozone or ozone water for a treatment system made of a liquid in which a hardly decomposable organic compound such as dioxins is present or a treatment system in which a liquid is contained in soil. , A step of mixing tourmaline powder, and a step of adding an action of separating charges from the tourmaline powder on a crystal.

The hardly decomposable organic compound is not particularly limited and includes, for example, dioxins, bisphenols, phenol phenols, halogenated phenols, phthalates, estradiol, benzophenone, and trichloroethylene. No. These hardly decomposable organic compounds may be present in liquids such as factory effluents, but often in soils. In the present embodiment, when the hardly decomposable organic compound is present in the soil, the soil is mixed with a liquid, for example, ozone water, or conversely, an appropriate amount of ozone water is mixed with the soil to form a liquid. It is preferable to configure a similar reaction system.

Tourmaline is mainly dorapite (dra Vite), squall (s chor 1), ゥ paite (uvite), and Erbite (e1baite). In particular, Dubai is inexpensive, easy to obtain, and convenient for systematization. Although tourmaline powder can be obtained by pulverizing natural rock, it is more preferable to use a powder obtained by calcining and pulverizing the pulverized material once and then pulverizing it again. When the ceramic is used in this way, an excellent ozone activating effect can be exhibited at the surface, and the powder can be easily ground into a powder. In this case, the firing temperature for turning the drabite into a ceramic must be set to a temperature other than 900 to 100 ° C. If fired in this temperature range, the piezoelectricity of the graphite will be lost. In the present embodiment, a material obtained by baking the drapite at 1200 ° C. is used.

Means for imparting an electric charge separation effect to the tourmaline powder on the crystal include, for example, applying a predetermined voltage, applying a strong pressure by an impact such as ultrasonic waves, applying microwaves, heating, or the like. May be considered. Of these, the voltage is suitable for implementation because it can be realized with a simple configuration. It is also possible to apply the voltage directly to the soil.

FIG. 1 is a schematic view showing one embodiment of an apparatus for performing a method for decomposing a hardly decomposable organic compound according to the present invention. This hard-to-decompose organic compound decomposer 1 is composed of a decomposition reaction tank 2, an ozone injector 3, a tourmaline powder mixer 4, a stirrer 5, and a charge separator 6.

Decomposition reactor 2 is the body processes degrade hardly decomposable organic compound is carried out, _c contaminated wastewater and soil is provided with inlet 2 a to be inputted also to the ozone injector 3 The ozone water generated in advance may be stored in a storage tank and injected as appropriate, or a known ozone generator may be provided to generate and inject ozone gas. The tourmaline powder mixer 4 mixes a predetermined amount of tourmaline powder into the decomposition reaction tank 2 in accordance with the type and amount of wastewater or soil to be decomposed. Also, A stirrer 5 is provided in the decomposition reaction tank 2, and the stirrer 5 stirs and mixes the mixed ozone water and tourmaline powder with the wastewater and soil containing the hardly decomposable organic compound. ing.

The charge separator 6 separates electric charge from the tourmaline powder on the crystal.For example, a positive electrode 6a and a negative electrode 6b are arranged in the decomposition reaction tank 2 to apply a predetermined voltage. . As another means, an ultrasonic generator may be provided, and an impact pressure by ultrasonic waves may be applied to the tourmaline powder to separate electric charges. In addition, it is conceivable that a micro-loop generator is arranged to irradiate tourmaline powder to separate charges on the crystal. Further, a heat generating device may be provided to heat the crystals of tourmaline powder to have electric charges on the surface. It is also possible to effectively treat a plurality of means for causing charge separation on the crystals of tourmaline powder as described above.

As described above, when the electric stone powder mixed into the decomposition reaction tank 2 is separated on the crystal by the action of the charge separator 6, the ozone is activated by the strong polarization charge generated at the crystal axis end. Increases decomposition processing ability. Further, since the hardly decomposable organic compound is adsorbed on the surface of the tourmaline powder where the ozone is activated, a decomposition reaction by the activated ozone occurs at a high probability, and the action of the hardly decomposable organic compound is caused by these actions. Decomposition is promoted.

Next, the operation and effect of the method for decomposing a hardly decomposable organic compound according to the present embodiment will be described with reference to examples.

[Example 1]

In Example 1, a decomposition experiment of 2,6-dichloro-14-nitrophenol (hereinafter sometimes abbreviated as DCNP in the drawings) was performed. As shown in Fig. 2, 2,6-dichloro-1,4-trophenol is a model substance for the dioxin decomposition intermediate. This 2, 6—dichro mouth _ 4 12 Trofe It has been confirmed that there is a correlation between the degradation of knol and the degradation of dioxin.

The experimental conditions of Example 1 will be described. In Example 1, a 10 ppm aqueous solution in which 2,6-dichloro-14-nitrophenol was dissolved in pure water was used as an aqueous solution.

(Liter) Prepared and placed in a container. Ozone gas was injected into this aqueous solution at 100 mg / h, and the mixture was stirred with a screw. To this experimental treatment system, 2,000 mesh of dry powder was added in a concentration of 30% v / V to 2.41 and a DC voltage of 30 V was applied to the plus and minus electrodes composed of platinum. . The aqueous solution decomposed under such conditions was extracted every predetermined time, and the solution concentration was measured by spectrophotometry. Also, as Comparative Example 1, a decomposition experiment using only ozone was performed. First, the results of Comparative Example 1 are shown in Tables 1 and 3, and the results of Example 1 are shown in Tables 2 and 4.

[table 1]

No dry, 30V DC, ozone

2]

With drive, 30V DC, ozone

Tables 1 and 2 show that 2,6-dichloro-4 The change in the concentration of oral phenol is shown numerically, and the relative concentration ratio to the initial concentration is also shown in the lower row. FIGS. 3 and 4 are graphs showing changes in absorbance with the passage of reaction time. The horizontal axis indicates light wavelength (nm), and the vertical axis indicates absorbance.

First, as can be seen by comparing Tables 1 and 2, in the results of Comparative Example 1 using only ozone in Table 1, the concentration of 2,6-dichloro-4-122-trophenol decreases with the reaction time. However, the concentration was still 1.04 ppm even after 6 hours, and the relative concentration ratio to the initial concentration was 10.4%. In contrast, in the results of Example 1 with the addition of the drabites in Table 2, the concentration of 2,6-dichloro-412-trophenol decreased rapidly with the lapse of reaction time, and even when the concentration reached a low concentration range. The decomposition process proceeds quickly. After a lapse of 4 hours, the concentration decreased to 0.01 ppm or less, and the relative concentration ratio also decreased to 0.1% or less.

The results in Tables 1 and 2 are more evident in FIGS. 3 and 4, and in Comparative Example 1 in which only ozone in FIG. 3 was used, the smaller the absorbance, that is, the amount of 2,6-dichloro- 4 The lower the concentration of 12-trophenol, the smaller the decrease, and the absorbance around 30 ° nm to 400 nm tends to decrease the substantial reaction rate when the absorbance is less than 0.05. On the other hand, in the results of Example 1 with the addition of the drive shown in FIG. 4, even in the region where the absorbance is small, that is, even in the region where the concentration is low, the momentum of the concentration decrease does not decline and the substantial reaction rate is maintained. Absorbance reached almost 0.0 after 4 hours as it was. In the results of Example 1, the initial concentration of 2,6-dichloro-4-nitrophenol already showed 7.28 ppm. This is because 30% (vZv) of drabite powder was added to a 10 ppm aqueous solution of 2,6-dichloro_42-to-mouth phenol, and the concentration of the aqueous solution after filtration for absorbance measurement was adsorbed on the drabite. It's just lower. 4 hours After that, the adsorbed amount of drabite of 2,6-dichloro-1-412 phenol was almost zero.

Further, based on the results of Example 1 and Comparative Example 1, a graph as shown in FIG. 5 was prepared in order to investigate the decomposition mechanism by the powder of the powder. FIG. 5 is a graph in which the horizontal axis indicates elapsed time, and the vertical axis indicates relative absorbance to the initial concentration. The graph of Comparative Example 1 is indicated by white circles, and the graph of Example 1 is indicated by black circles. As indicated by the open circle graph, the graph showing decomposition by ozone alone has an exponential decreasing curve, and the contact reaction (collision reaction) between ozone and 2,6-dichloro-14-nitrophenol is shown in FIG. It shows that it has occurred, and it matches theoretically.

However, in the case of using drabite, as shown in the graph of Hatoma Kuromaru, the decrease of 2,6-dichloro-1-412 tropanol is dependent on the exponential decrease and the linear decrease with time. It is allowed to include both. This linear decrease is indicative of the time dependence typical of surface catalysis (zero-order reaction). This phenomenon indicates that in addition to the contact reaction between ozone and 2,6-dichroic _412 tropanol, further reactions are occurring. Probably, on the surface of the drabite powder, the action of adsorbing 2,6-dichloro-412-trophenol and the action of activating ozone due to the strong polarization charge on the crystal axis end occurred. It is considered that the activated ozone decomposes 2,6-dichloro-412-trophenol efficiently on the surface. In other words, when drabite is mixed in, ozone is activated to generate reactive oxygen species such as atomic oxygen and 〇H radicals, which are present in the solution.

Collides with 6-dichloro-4-nitrophenol to decompose it. Of course, the collision probability is not 100%, but the amount of collision decreases as the concentration of 2,6-dichloro-412-trophenol decreases. The reaction rate decreases. However, the action of adsorbing 2,6-dichloro_412-trotropenol occurs on the surface of doravite, and the active oxygen species are successively generated on the surface. 2,6-dichloro-1,412-trophy: The amount of collision with phenol does not decrease, and the decomposition reaction can proceed efficiently even at low concentrations. Thus, the graph shown in Fig. 5 suggests that the drabite functions as an ozone activation trigger and also functions as a reaction site for the decomposition reaction due to the adsorption of the drabite powder surface. Is what it is.

Although a voltage of 30 V was applied in both experiments of Example 1 and Comparative Example 1, the current value was 0 A in the processing system of Comparative Example 1, whereas the drive value was 0 in Example 1. When mixed, the current value shows 0.18 A, and it is recognized that polarized charges are generated in the drive powder.

[Example 2]

Next, in Example 2, an experiment for decomposing dibenzoparadioxin was performed. The experimental conditions in Example 2 were almost the same as in Example 1, but dibenzoparadioxin had low solubility in water, and was dissolved in water containing 30% ethanol to prepare a 10 ppm solution. For comparison with Example 2, a decomposition treatment without a devolatilizer was performed as Comparative Example 2. First, the results of Comparative Example 2 are shown in Table 3 and FIG. 6, and the results of Example 2 are shown in Table 4 and FIG.

[Table 3]

No dry, 30V DC, ozone

[Table 4]

With drive, 30V DC, ozone

Tables 3 and 4 show the change in the concentration of dibenzoparadioxin over time with the numerical value, and also show the relative concentration ratio to the initial concentration. Fig. 6 and Fig. 7 are graphs showing the change in absorbance with the passage of reaction time. The horizontal axis indicates light wavelength (nm), and the vertical axis indicates absorbance.

Comparing Tables 3 and 4, the results of Comparative Example 2 using only ozone in Table 3 show that the dibenzoparadioxin concentration decreases with the lapse of reaction time. Thus, the relative concentration ratio to the initial concentration remained at 55.1%, and was 39.3% even after 18.5 hours. On the other hand, in the results of Example 2 with the addition of the drabite in Table 4, the dibenzoparadioxin concentration rapidly decreased with the passage of reaction time, and continued to decrease even when the concentration became lower, and for 3 hours After the elapse, the concentration decreased to less than half of the initial concentration of 49.6%, and after 13 hours, decreased to 17.2%. In Comparative Example 2, it took 18.5 hours for the concentration to decrease to 39.3%, whereas in Example 2, the concentration decreased to 37.7% in 5 hours. . In other words, the speed difference of _c further the degradation process would be reduced by about 4 times the time to reduce the concentration by mixing Dorabai preparative 40% or less, and this of significant differences occur at lower concentrations Power S

In Tables 3 and 4, the initial concentration was 10.0 in Comparative Example 2. In contrast to 0 ppm, in Example 2, it is different from 15.06 ppm. This is because the concentration of dibenzoparadioxin before the reaction was adjusted to 10 ppm with respect to the total weight of drabite and a 30% aqueous ethanol solution in Example 2 in which drabite was added, and this was used as the absorbance. The concentration of dibenzoparadioxin in the solution was higher than 10 ppm because of removal of the drabite by filtration for measurement. This result also indicates that dibenzoparadioxin is hardly adsorbed on the drug in the case of an aqueous solution containing ethanol.

On the other hand, referring to FIGS. 6 and 7, as described above, since the initial concentration is different between Example 2 and Comparative Example 2, it is difficult to understand even if the absorbance values themselves are compared. Is clearly larger in the second embodiment. Also, when comparing the positions where the graphs converge, in Comparative Example 2, the absorbance tends to converge slightly above the 0.0 line, but in Example 2, it converges to the absorbance 0.0 line. This indicates that the substantial reaction speed in the low concentration range is maintained.

As described above, according to the present embodiment, ozone is activated by the strong polarization charge generated at the crystal axis end by separating charge on the crystal and the pyroelectric having remarkable pyroelectricity. To accelerate the decomposition process. In addition, it is considered that the decomposition reaction of activated ozone is efficiently performed on the surface of doravite by the adsorption action of the hardly decomposable organic compound. By these actions, it is possible to rapidly decompose hardly decomposable organic compounds such as 2,6-dichloro-1--4-phenol and dibenzoparadioxin, and to maintain the substantial reaction rate even in a low concentration range. it can.

In addition, the method for decomposing a hardly decomposable organic compound according to the present embodiment does not require ultraviolet rays, and it is only necessary to use an inexpensive and easily controllable material, which is a mixture of drabite powder. Can be carried out by the soil There are many merits when applied to purification facilities.

The configurations of the present embodiment of the present invention are not limited to those described above, and can be appropriately changed. Industrial applicability

As described above, according to the present invention, ozone can be effectively activated to accelerate the decomposition treatment of a hardly decomposable organic compound, and the hardly decomposable organic compound existing at a low concentration can be quickly removed. It has the effect that it can be decomposed.

Claims

The scope of the claims

1. A method for decomposing a hardly decomposable organic compound, which comprises injecting ozone into a treatment system in which the hardly decomposable organic compound is present, and decomposing the hardly decomposable organic compound by bringing the hardly decomposable organic compound into contact with ozone;

An ozone injecting step of injecting ozone into a system such as a liquid in which a hardly decomposable organic compound is present or a system in which a liquid is contained in soil in which a hardly decomposable organic compound is present;

A tourmaline powder mixing step of mixing tourmaline powder into the treatment system; and a tourmaline powder charge separation step for effecting charge separation on the crystal of the tourmaline powder mixed in the tourmaline powder mixing step;

A method for decomposing a hardly decomposable organic compound, comprising:

2. The method for decomposing a hardly decomposable organic compound according to claim 1, wherein the tourmaline powder is a ground tourmaline ceramic powder obtained by firing natural tourmaline to ceramic. Method.

3. The method for decomposing a hardly decomposable organic compound according to claim 2, wherein the tourmaline powder is a drabite ceramic powder obtained by sintering natural drabite.

4. The tourmaline powder charge separation step according to any one of claims 1 to 3, wherein a voltage is applied to the treatment system to cause the tourmaline powder to perform charge separation on a crystal. A method for decomposing hardly decomposable organic compounds.

5. An apparatus for decomposing hard-to-decompose organic compounds, comprising: a decomposition reaction tank in which a step of decomposing a hardly decomposable organic compound is performed; and an ozone injection means for injecting ozone into the decomposition reaction tank. Means for mixing tourmaline powder into the tank, and charge separation of the tourmaline powder mixed on the crystal A device for decomposing hardly decomposable organic compounds, the device comprising: a charge separation means for adding a function to the organic compound.