JP2011161218A - Detoxification method of solid containing organohalogen compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detoxification method of a solid containing an organohalogen compound, having excellent processing efficiency while an operating condition is mild and the energy consumption amount is small. <P>SOLUTION: The solid containing the organohalogen compound and a metal particle as an electron donor are brought into contact with each other to reduce the organohalogen compound and detoxify the same. At this time, at least some of the metal particles to be used are particles of nano size. The metal particles including particles of nano size are obtained by crushing a mixture of solid-like metal and water adsorption and desorption agent and/or a porous inorganic material until at least some of the solid-like metal becomes nano size. The obtained metal particles are dispersed in the water adsorption and desorption agent and/or a porous inorganic material to form a metal dispersed body. Thus, the high activity can be maintained. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for detoxifying a solid containing an organic halogen compound that detoxifies solids such as soil, incineration ash, incineration fly ash, and sludge containing an organic halogen compound typified by dioxins.

  Chemical or biological treatment methods to detoxify soil contaminated with persistent organic pollutants (POPs) and / or volatile organic compounds (VOC) such as dioxins and PCBs Many treatment methods using methods have been researched and developed. Regarding the decomposition of POPs by chemical methods, many dechlorination methods have been developed at the laboratory level so far, but unfortunately they are often not directly available in the field. One reason is that it is difficult to efficiently contact POPs adsorbed in a heterogeneous solid phase such as soil and a decomposing agent, and the decomposing agent is deactivated due to the influence of coexisting substances such as moisture. Because.

  Turning to practical technologies, indirect heating oxidative decomposition method, geosteaming method, solvent extraction method, bioremediation method and the like are well known. However, since the indirect heating oxidative decomposition method and geosteaming method involve heating, the amount of energy input per unit processing amount is enormous and the cost is high. On the other hand, in the solvent extraction method in which the processing temperature is suppressed, a hydrocarbon solvent having a high boiling point is added to increase the extraction efficiency, so that it is difficult to completely separate the solvent from the object. In the bioremediation method, it takes time to decompose, takes time to control the optimal decomposition conditions, and further, there is a limit to the decomposable objects, so it must be combined with other methods. Hot soil method that purifies contaminated soil by adding and mixing hot soil (registered trademark) consisting of quick lime and the like that comes into contact with water and generating heat to soil contaminated by VOC, and volatilizing and separating VOC by the generated heat of hydration Cannot decompose POPs.

  In addition, in the mechanochemical method, POPs in the solid phase can be rendered harmless at room temperature by the shock wave of the planetary ball mill, but the amount of addition of calcium oxide as a decomposition aid reaches several to several tens of times that of the object to be processed. The milling efficiency decreases as the concentration increases (for example, see Non-Patent Document 1). In addition, the mechanochemical method using calcium oxide as a reducing agent is not practical because the final amount of waste increases.

  In contrast, the present inventors have found a novel POPs decomposition technique using metallic calcium and achieved a high treatment efficiency of 99% or more (see, for example, Non-Patent Document 2). This method is a wet reaction using metallic calcium as an electron source in the presence of alcohol (see, for example, Patent Document 1). This treatment method is a useful method, but since a flammable lower alcohol is used, a safer and cheaper treatment method has been demanded. For this reason, we developed a method of supplying the energy required for dechlorination reaction from the outside using a planetary ball mill without using alcohol. Using this method, the dioxin-containing incinerated ash was treated at room temperature, and the initial concentration of 3000 to 5000 pgTEQ / g was successfully rendered harmless to the lower detection limit (0.1 pgTEQ / g) (for example, Non-Patent Document 3). reference).

Japanese Patent No. 3785556

“Elucidation of Degradation Mechanism of Dioxins during Mechanochemical Treatment” Y. Nomura, S. Nakai, M. Hosomi, Environ. Sci. Technol., 39, 3799-3804 (2005) ”Highly effective degradation of polychlorinated biphenyls in soilmediated by a Ca / Rh bicatalyticsystem,” Y. Mitoma, N. Egashira, C. Simion, Chemosphere, 74, 968-973 (2009) “Current Condition of Dioxins Emitted by Incineration and Degradation of Dioxins Using Metallic Calcium,” M.Takase, M.Kakeda, Y.Yoshino, Y.mitoma, Bull.Hiroshima Pref.Univ.19,69-81 (2007)

  Although the method using the planetary ball mill developed by the present inventor can efficiently detoxify soil contaminated with dioxins, the cost of the apparatus becomes very high when an actual machine is assumed. In addition, as described above, other methods for detoxifying contaminated soil that have been developed and proposed so far have problems in energy consumption, processing efficiency, processing speed, equipment cost, running cost, etc. There is a need for improvement.

  An object of the present invention is to provide a method for detoxifying a solid containing an organic halogen compound that is excellent in processing efficiency while being low in energy consumption under mild operating conditions.

  The present invention according to claim 1 is a method of detoxifying the organic halogen compound by bringing a solid containing the organic halogen compound into contact with metal particles as an electron donor, wherein at least a part of the metal particles is A method for detoxifying a solid containing an organic halogen compound, comprising nano-sized particles, wherein the organic halogen compound is reduced and detoxified.

  The present invention according to claim 2 is the method of detoxifying a solid containing the organohalogen compound according to claim 1, wherein the metal particles have a function of adjusting moisture with a solid metal and function as a hydrogen source. The water adsorbing and desorbing agent and / or the porous inorganic material that adsorbs and desorbs the water to the metal particles obtained by pulverizing the solid metal until at least a part of the metal becomes nano-sized, and / or It is provided as a metal dispersion dispersed in a porous inorganic material.

  Further, the present invention described in claim 3 is the method for detoxifying a solid containing the organohalogen compound according to claim 2, wherein the metal dispersion has a surface of nano-sized metal particles attached to the water adsorption / desorption agent and The porous inorganic material is coated, and the water adsorption / desorption agent and / or the porous inorganic material prevents most of the nano-sized metal particles from coming into direct contact with oxygen, carbon dioxide or water. To do.

  According to a fourth aspect of the present invention, there is provided the method for detoxifying a solid containing the organic halogen compound according to the first aspect, wherein the metal particles are used in the treatment for detoxifying the organic halogen compound. The solid containing a solid and a solid metal are obtained by pulverizing such that at least a part of the solid metal is nano-sized.

  Further, the present invention according to claim 5 is the method for detoxifying a solid containing the organic halogen compound according to claim 4, further comprising adding a water adsorption / desorption agent and / or a porous inorganic material, An agent and / or a porous inorganic material are pulverized simultaneously.

  Further, the present invention according to claim 6 is a method for detoxifying a solid containing the organic halogen compound according to any one of claims 1 to 5, compared with a planetary ball mill without actively heating from the outside. The organic halogen compound is reduced and rendered harmless while stirring using a mill having a low energy density in the mill.

  Further, the present invention according to claim 7 is the method of detoxifying a solid containing the organic halogen compound according to any one of claims 1 to 6, and further, alcohol and / or organic acid as a hydrogen source coexist. The organic halogen compound is reduced and rendered harmless.

  Further, the present invention according to claim 8 is the method for detoxifying a solid containing the organic halogen compound according to claim 7, wherein the solid containing the organic halogen compound is soil, incineration ash, incineration fly ash, sludge Or a mixture thereof, wherein the alcohol and / or organic acid is an alcohol and / or organic acid or the like contained in soil, incineration ash, incineration fly ash, sludge, or a mixture thereof. .

  The present invention according to claim 9 is the method of detoxifying a solid containing an organic halogen compound according to any one of claims 1 to 8, wherein the amount of water contained in the solid containing the organic halogen compound is When it exceeds a predetermined value, prior to the detoxification treatment of the organic halogen compound, a water adjusting agent is added to the solid to adjust the water content so that the amount of water contained in the solid is not more than a predetermined value. And

  Further, the present invention according to claim 10 is the method for detoxifying a solid containing the organic halogen compound according to any one of claims 1 to 9, wherein the metal particles are alkali metal, alkaline earth metal, It is characterized by containing at least one of group 3 elements, iron, zinc and alloys containing these.

  The present invention according to claim 11 is the method of detoxifying a solid containing the organic halogen compound according to any one of claims 1 to 10, wherein the organic halogen compound is a residual organic pollutant and / or It is a volatile organic compound.

  Further, the present invention according to claim 12 is the method for detoxifying a solid containing the organic halogen compound according to claim 11, wherein the vapor of the volatile organic compound generated when the organic halogen compound is further detoxified. Adsorbed on an adsorbent and mechanochemically treating the adsorbent and metal particles as an electron donor, or at least partly dissolved in the adsorbent and a protic solvent and having a reducing power by electron transfer and proticity It includes a step of mixing with a solvent and detoxifying volatile organic compounds.

  The method for detoxifying a solid containing an organic halogen compound according to the present invention is a method in which a solid containing an organic halogen compound and metal particles that are nano-sized electron donors are brought into contact with each other to reduce and detoxify the organic halogen compound. Yes, a high detoxification rate can be achieved with mild operating conditions. There is no need to actively heat from the outside, and energy consumption is low.

2 is an electron micrograph (SEM) of the metallic calcium nanodispersion (1) produced in Example 1. FIG. It is GC-MS chromatogram before and behind experiment of Example 2, (a) is before an experiment, (b) is after an experiment.

  The method for detoxifying a solid containing an organic halogen compound according to the present invention is a method for detoxifying the organic halogen compound by bringing a solid containing the organic halogen compound into contact with metal particles which are an electron donor. At least a part of the metal particles is nano-sized particles, and the organic halogen compound is reduced and rendered harmless.

  Examples of the object to be treated of the method for detoxifying a solid containing the organic halogen compound according to the present invention include soil contaminated with POPs and / or VOC such as dioxins and PCB, incineration ash, incineration fly ash, sludge, or a mixture thereof. Is mentioned.

  The metal particles that are electron donors are substances that donate electrons and ions to the organic halogen compound. Specific examples include alkali metals, alkaline earth metals such as calcium metal, Group 3 elements such as aluminum, iron, zinc, and alloys containing these elements. These may be used alone or in combination, and metallic calcium can be suitably used.

  The metal particles that are electron donors are at least partially nano-sized particles. Such metal particles can be pulverized with a pulverizer until at least a part of the solid metal is nano-sized by a mixture of the solid metal and the water adsorption / desorption agent and / or the porous inorganic material. preferable. The mixing ratio of the metal and the water adsorbing / desorbing agent and / or the porous inorganic material is preferably 1: 2 by weight, but is not limited to this ratio, and is 1:20 to 50 by weight, The mixing ratio may be reduced. Examples of the water adsorption / desorption agent that can be used here include calcium oxide, and examples of the porous inorganic material include celite (Celite is a registered trademark of Celite Corporation), silica gel, and activated carbon. Celite is diatomaceous earth calcined with sodium carbonate and can retain a large amount of moisture.

  The pulverized product thus obtained is a metal dispersion in which metal particles including nano-sized metal particles are dispersed in a water adsorption / desorption agent and / or a porous inorganic material. In the metal dispersion, the surface of the nano-sized metal particles is coated with a water adsorption / desorption agent and / or a porous inorganic material. Generally, when a metal is refined to a nano size, it is oxidized and deactivated in the environment. However, in the metal dispersion, a water absorption / desorption agent and / or a porous inorganic material covering the surface of the nano size metal particles is provided. Since most of the metal particles are prevented from coming into direct contact with oxygen, carbon dioxide, or water, the nano-sized metal particles can maintain high activity even in the atmosphere. As a result of the experiment, metallic calcium ground with Celite (registered trademark) had an activity of 90% or more as an electron source, and could be stably present in the atmosphere for 2 months or more. Similarly, the calcium metal ground with calcium oxide maintained 80% or more of the initial activity for 1 month or more at room temperature in the atmosphere.

  Further, the water absorption / desorption agent and / or the porous inorganic material functions as a moisture adjusting agent that adsorbs moisture contained in an object to be treated such as contaminated soil. The water absorption / desorption agent and / or the porous inorganic material desorbs the adsorbed water. This water acts as a hydrogen source.

  Next, taking a soil containing dioxins (hereinafter referred to as contaminated soil) as an example, the metal dispersion in which metal particles containing nano-sized metal particles are dispersed in a water adsorption / desorption agent and / or a porous inorganic material. A method of detoxifying using the body will be described.

  A metal dispersion is added to the contaminated soil, and these are stirred and mixed as necessary to bring the contaminated soil into contact with the nano-sized metal particles. As a result, the organic halogen compound is reduced and rendered harmless by dehalogenation, ring reduction reaction or the like. These operations can be performed at room temperature and do not need to be positively heated from the outside. Although the addition ratio of the metal dispersion to the contaminated soil varies depending on the amount of dioxins contained in the contaminated soil, it can be about 1/100 by weight. This value is about 1/5 to 1/200 of the amount of calcium oxide used in the mechanochemical method using conventional calcium oxide, and is very small. As a result, the amount after treating the contaminated soil hardly increases compared to the amount of the contaminated soil before the treatment. This is one of the features of the present invention.

  To increase the detoxification rate and detoxification rate (decomposition rate) of dioxins contained in contaminated soil, it is important to increase the chance of contact between dioxins in contaminated soil and metal particles that are nano-sized electron donors It is. For this reason, it is preferable to stir and mix the contaminated soil and the metal dispersion, and it is more preferable to stir and mix the contaminated soil and the metal dispersion while updating the surface of the contaminated soil and / or the metal dispersion. Therefore, a mill having a pulverizing function is preferable as a stirring mixer. Since the stirring and mixing is an operation performed to increase the chance of contact between the dioxins in the contaminated soil and the metal particles that are nano-sized electron donors, the stirring strength may be small. Therefore, the stirring and mixing can be performed using a mill having a smaller energy density in the mill as compared with the planetary ball mill. Examples of such a mill include a roller mill and a tower mill. The planetary ball mill can apply high energy, but requires a large amount of power and is difficult to increase in size. On the other hand, roller mills are also used for pulverization of coal at coal-fired thermal power plants. Handbook, Revised 6th edition, page 846), it can be said to be a preferable mill for proceeding with the treatment of contaminated soil on a large scale.

  In the mechanochemical treatment, it is necessary to give the energy necessary for detoxification of dioxins through the mill, but in this method, the stirring and mixing operation only needs to increase the contact opportunity between the contaminated soil and the metal dispersion, It is not necessary to give the energy required for detoxification of dioxins through a stirring and mixing operation. In this method, dioxins can be rendered harmless even under low energy input conditions by using a metal that is an electron donor that has been refined to a nano size. In general, a metal, which is an electron donor that has been miniaturized to a nano size, has high activity and reactivity, but reacts with oxygen, carbon dioxide or water in the atmosphere due to its high activity and reactivity, and deactivates. . For this reason, even if it uses the metal which is an electron donor refined | miniaturized to nanosize as it is, dioxins cannot be made harmless. However, here, by using the metal dispersion, it is possible to maintain the activity of the metal, which is an electron donor refined to a nano size, in a high state, and to detoxify dioxins even under low energy input conditions. it can.

  The stirring and mixing operation can also be performed as follows. Since dioxins contained in contaminated soil are often present on the soil surface, it is assumed that most dioxins are present on the contaminated soil surface when the content of dioxins in the contaminated soil is low. The In such a case, once the contaminated soil and the metal dispersion are uniformly mixed, stirring may be stopped. At this time, by heating at a temperature of 200 ° C. or less only at the initial stage, the dioxins in the contaminated soil can be detoxified at a stretch, and then the heating and stirring can be stopped to gradually detoxify the remaining dioxins. Good. Similarly, the reaction accelerator is added in the initial stage, and the dioxins in the contaminated soil are detoxified. After that, without adding the reaction accelerator, the stirring is stopped and the remaining dioxins are gradually harmless. You may make it. By proceeding with detoxification of dioxins at an early stage, the concentration of the metal dispersion with respect to the dioxins becomes relatively high, so that the dioxins in the contaminated soil can be detoxified efficiently. Since heating is performed only in the initial stage, the energy consumption is very small, which is advantageous in terms of cost. On the other hand, when the content of dioxins in the contaminated soil is large, it is presumed that dioxins are also present inside the contaminated soil. Therefore, stirring and mixing that renews the surface of the contaminated soil and / or metal dispersion is performed. Preferably it is done.

  Another mode of detoxifying the contaminated soil containing dioxins with the metal particles that are nano-sized electron donors will be described. In the above method, the metal particles that are nano-sized electron donors were provided as a preliminarily prepared metal dispersion, but here, metal particles that are nano-sized electron donors are provided in the process of detoxifying contaminated soil. .

  The contaminated soil and the metal that is a solid electron donor are pulverized using a pulverizer so that at least a part of the solid metal is nano-sized. In this method, in the process of detoxifying contaminated soil, the metal as an electron donor is made nano-sized, and dioxins are reduced and detoxified. At this time, it is preferable to simultaneously add a porous inorganic material such as Celite (registered trademark) and / or a water absorption / desorption agent such as calcium oxide and pulverize them simultaneously. When the porous inorganic material and / or the water adsorption / desorption agent are contained in the contaminated soil, it is not necessary to add the porous inorganic material and / or the water adsorption / desorption agent separately. Thereby, like the said method, it can maintain, without losing the activity of the metal particle which is a nanosized electron donor. Here, the pulverizer only needs to be able to pulverize so that at least a part of the solid metal is nano-sized, and it is not necessary to use a planetary ball mill. Also in this method, it is not necessary to actively heat from the outside.

  Contaminated soil and sludge often contain moisture. Incineration ash, incineration fly ash, etc. are also left unattended to absorb moisture in the air or spray water to prevent scattering. Often contains. When the dioxins and the like contained in contaminated soil containing water are detoxified by the above method, if the water concentration is about 5% by weight or less, it may be detoxified by the above method as it is. Water, organic acids, amines, metal hydrides, and / or alcoholic hydroxyl groups, etc. contained in contaminated soil, etc. function as a hydrogen source in the treatment process of the above detoxification method, and thus do not need to be removed. .

  However, when the contaminated soil contains a lot of water, it is preferably detoxified in the following manner. When contaminated soil or the like contains a large amount of moisture, it is not a problem to make it harmless by the above method, but when the amount of moisture is large, the amount of metal particles added as electron donors increases. For this reason, in the said detoxification method, it is preferable to add and process calcium oxide simultaneously. Calcium oxide functions as a moisture adjuster that absorbs moisture and functions as a decomposition aid. Furthermore, the heat generated when calcium oxide reacts with water to form calcium hydroxide acts to increase the detoxification rate. To do. The calcium oxide added here can utilize the calcium oxide added as the water adsorbing and desorbing agent. Therefore, when decontaminating contaminated soil containing a lot of water, the contaminated soil, calcium oxide and solid electrons The donor metal can be detoxified while being pulverized by a pulverizer so that at least a part of the solid metal is nano-sized.

  Furthermore, when detoxifying contaminated soil having a high water content and a water concentration exceeding 40% by weight, it is preferable to use a two-step method. The two-step method is the first step, in which calcium oxide is added to the contaminated soil containing water after being dehydrated by filtration operation or the like as necessary, and after adjusting the moisture, the second step is nano size. In this method, a metal which is an electron donor source is added and detoxified by the above method. Moisture adjustment in the first step can also be performed using a roller mill and without forcibly heating from the outside, and the detoxification process in the second step is followed by the moisture adjustment process in the first step. A metal dispersion containing a metal that is a nano-sized electron donor may be added to the mill. The amount of addition of the metal as the electron donor can be further reduced by separating the step of adjusting the moisture by adding calcium oxide and the step of adding the metal as the nano-sized electron donor and detoxifying it. .

  Next, the point of detoxification of contaminated soil or the like containing VOCs in addition to dioxins will be described. The detoxification of the contaminated soil is performed by appropriately selecting the above detoxification method according to the amount of water. Even if the soil contains VOC in addition to dioxins, there is basically no difference from the procedure for detoxifying contaminated soil containing dioxins. However, in the detoxification process, there is a possibility that VOC is partially vaporized and discharged from the mill. Therefore, the exhaust gas discharged from the mill is guided to the exhaust gas treatment device, and the VOC is trapped here. By using an exhaust gas treatment apparatus made of an adsorbent such as activated carbon, VOC can be easily trapped. The adsorbent that has adsorbed VOC is separately added with a metal as an electron donor and subjected to mechanochemical treatment, or at least partly dissolved in the adsorbent and a protic solvent and has a reducing power by electron transfer and proton. A VOC may be rendered harmless by mixing with an organic solvent. Such a processing method is described in detail in Japanese Patent Application Laid-Open No. 2008-207044 and Japanese Patent No. 3785556. When decontaminating contaminated soil containing dioxins and the like that do not contain VOCs, it is natural that exhaust gas discharged as needed may be guided to an exhaust gas treatment device and the exhaust gas purified in the same way. It is.

  As shown in the above embodiment, the method for detoxifying a solid containing an organic halogen compound according to the present invention does not require forcibly heating from the outside, and the apparatus used for stirring and mixing also has a power consumption such as a roller mill. Since a small mill can be used, soil contaminated with dioxins can be rendered harmless with less energy. A high detoxification rate and a high detoxification rate can be achieved by using a nano-sized metal as the electron donor metal while consuming little power and mild operating conditions. In addition, since a solid-state detoxification method containing an organic halogen compound according to the present invention can be carried out using a general-purpose apparatus, it is easy to increase the size and capacity, and the processing cost in an actual machine is also low. Become. Moreover, the solid detoxification method containing the organic halogen compound according to the present invention does not require washing of contaminated soil or the like prior to the detoxification treatment. This is also one of the characteristics of this detoxification method.

  Furthermore, handling becomes easy by disperse | distributing the metal which is a nanosize electron donor to a water adsorption / desorption agent and / or a porous inorganic material. In the method for detoxifying a solid containing an organohalogen compound according to the present invention, the temperature is increased by heat of hydration of a metal having frictional force by a roller mill or the like, heat generation by shearing force, reduction power, and further by hydration heat of calcium oxide. Although it rises, unlike the method of applying heat by forcibly heating from the outside, the temperature in the mill can be made 200 ° C. or lower, and impurities and chlorine content react at 350 to 500 ° C. The possibility that dioxins are generated can be eliminated.

  Further, in the method for detoxifying a solid containing an organic halogen compound according to the present invention, when calcium metal is used as the metal as the electron donor, the calcium does not become an obstacle to making contaminated soil into a cement material. If a high-chlorine content is treated, after removing calcium chloride by washing the treated soil, a kiln can be used as a cement material. In general, after the treatment of contaminated soil, it is difficult to secure a disposal site for the treated soil. Furthermore, although the soil after VOC processing is generally contaminated with oil, in the kiln processing, it can be positioned as soil containing a combustion aid. At this time, chlorine is in a combustion environment that is difficult to generate as dioxin by adding calcium.

Example 1
Production of Metal Calcium Nanodispersion (1) 1 g of metal calcium and 5 g of celite were subjected to normal temperature pulverization treatment at 400 rpm for 60 minutes in a nitrogen gas atmosphere using a planetary ball mill. The milled product was classified in a nitrogen gas atmosphere to obtain a 2 mm sieved product. This was designated as metal calcium nanodispersion (1). An electron micrograph (SEM) is shown in FIG. From an electron micrograph, it was confirmed that at least a part of metallic calcium was 50 to 100 nm. The metal calcium content in the obtained metal calcium nanodispersion (1) was calculated from the amount of hydrogen generated upon contact with water by a water displacement method. As a result of the experiment, the hydrogen gas generation amount is 5 to 15 ml with respect to 0.5 g of the metal calcium nanodispersion (1). From this result, the metal calcium content per 1 g of the metal calcium nanodispersion (1) is , 0.018-0.054 g.

Detoxification experiment To 1 g of contaminated soil containing PCB with an initial concentration of 2850 mg / kg, 1 g of the above metal calcium nanodispersion (1) (metal calcium content 0.054 g) was added, and using a roller mill type pulverizer, Stir at ambient temperature for 24 hours. Thereafter, hydrochloric acid was added to quench the reaction completely, and the total amount of organic matter was collected with diethyl ether and concentrated. The total amount was analyzed by the GC-ECD method according to the official method. The analytical value was 34 mg / kg.

Example 2
A detoxification experiment was conducted under exactly the same conditions as in Example 1. The PCB with an initial concentration of 2850 mg / kg was 120 mg / kg. The GC-MS chromatogram at this time is shown in FIG. FIG. 2 (a) is a GC-MS chromatogram of contaminated soil containing an initial concentration of 2850 mg / kg PCB before the experiment, and FIG. 2 (b) is a contamination containing 120 mg / kg PCB after the experiment. It is a GC-MS chromatogram of soil. It can be seen that after the detoxification experiment, the concentration of each component was greatly reduced. Furthermore, as indicated by broken lines in the figure, the ratio of each component changed greatly before and after the detoxification experiment.

Example 3 to Example 6
Production of Metal Calcium Nanodispersion (2) Metal calcium nanodispersion (2) was produced in the same manner as metallic calcium nanodispersion (1) using calcium oxide instead of celite. The metal calcium content in the obtained metal calcium nanodispersion (2) was calculated from the amount of hydrogen generated upon contact with water by a water displacement method. As a result of the experiment, the hydrogen gas generation amount was 100 ml with respect to 1.0 g of the metal calcium nanodispersion (2). From this result, the metal calcium content per 1 g of the metal calcium nanodispersion (2) was 0. 357 g.

Detoxification experiment As shown in Table 1, 1 mmol of 2-chlorobiphenyl was added to 10 g of mash under a 500 μm sieve, and this was used as a specimen. Each specimen has a different moisture content, and the specimen of Example 3 does not contain any moisture. The experiment was performed in the same manner as in Example 1. The experimental results are shown in Table 1. As a result of the experiment, the more water contained in the specimen, the more harmless. However, 2-chlorobiphenyl was reduced even when the specimen did not contain any moisture. When the water content in the specimen was low, the dechlorination reaction proceeded, and when the water content in the specimen was high, the ring reduction reaction proceeded.

Example 7
In the same manner as in Examples 3 to 6, 1 mmol of 2-chlorobiphenyl was added to 10 g of mash under a 500 μm sieve, and this was used as a specimen. The moisture content of the masa soil at this time was 1.28% by weight. An experiment was performed in the same manner as in Example 1 by adding 1.0 g of the metal calcium nanodispersion (2) and 1.0 g of activated carbon containing 10% by weight of water to the specimen. As a result of the experiment, 2-chlorobiphenyl was detoxified and a dimer was produced.

Example 8
An experiment was conducted in which 1.0 g of silica gel containing 3% by weight of water was added to the specimen instead of the activated carbon of Example 7. As a result of the experiment, the ring reduction reaction proceeded and 2-chlorobiphenyl was rendered harmless.

Comparative Example 1
In place of the metal calcium nanodispersion (2), a detoxification experiment was conducted under the same conditions as in Example 4 using metal calcium containing no nano-sized particles. However, the addition amount (preparation amount) of metallic calcium was 0.05 g. Detoxification did not progress compared to Example 4. The results are shown in Table 1.

Comparative Example 2
A detoxification experiment was performed under the same conditions as in Example 4 using calcium oxide containing no metal calcium at all and containing nano-sized particles in place of the metal calcium nanodispersion (2). However, the addition amount (preparation amount) of calcium oxide was 0.95 g. Detoxification did not progress compared to Example 4. The results are shown in Table 1.

Examples 9-17
As described below, the POPs-contaminated soil was detoxified using the metallic calcium nanodispersion. Commercially available metal Ca (φ2.0-2.5 mm, 0.43-0.48 m ² / g) and CaO (850 ° C., dried for 2 hours) were mixed at a ratio of Ca / CaO = 2/5, and in an Ar atmosphere Then, pulverization was performed at 600 rpm for 1 hour using a planetary ball mill (manufactured by Fritsch: model P-7). The obtained pulverized mixture was observed with a scanning electron microscope (JEOL, 6510ASEM-EDS). The amount of metallic Ca in the pulverized mixture was determined from the amount of hydrogen gas by the water displacement method. The soil moisture was measured according to JIS-Z7302-3, and the composition analysis was performed according to JIS-M8853 and M8855. A typical degradation test is as follows. Metal nano Ca / CaO pulverized mixture and POPs-contaminated soil are added to the mortar-type decomposition apparatus at a predetermined mixing ratio (mixing ratio of metal Ca to contaminated soil = 0.5 to 1.12 wt%), and an open system The mixture was stirred and mixed at room temperature for a predetermined time. After the treatment, the whole amount was recovered using a solvent, and the whole amount of residual POPs was analyzed. POPs analysis was performed by GC-ECD, GC / QMS, or HRGC / HRMS depending on the purpose. In all cases, the pretreatment conformed to the official law. Further, the decomposition efficiency (decomposition rate) was determined from the comparison of the total amount of POPs before and after the treatment.

  The amount of metallic Ca in the pulverized mixture was approximately 2.8 mmol / g-mixture (11.2 wt% Ca / g-mixture). Observation with an electron microscope revealed that the particles were aggregates having a particle size of 50 nm or less, and maintained 80% or more of the initial activity for 1 month or more at room temperature in the atmosphere. Next, the dechlorination activity of the ground mixture was examined. For example, it was confirmed that biphenyl was obtained by mixing a pulverized mixture containing 1 mmol of 2-chlorobiphenyl and 2.8 mmol of metal Ca in a mortar-type decomposition apparatus for 24 hours. Therefore, this method was applied to the treatment of POPs contaminated soil.

  Using the metal Ca / CaO pulverized mixture (11.2 wt% Ca / g-mixture) prepared to the nano size, POPs-contaminated soil was treated at normal temperature in the atmosphere. The ratio of the metal Ca / CaO pulverized mixture (11.2 wt% Ca / g-mixture) prepared to nanosize and the POPs-contaminated soil was 1 g: 9 g. The processing conditions and results are shown in Table 2. In Table 2, the amount of water is a value for POPs-contaminated soil to which a metal Ca / CaO pulverized mixture is added. As shown in Table 2, the decomposition of polychlorinated dibenzo-P-dioxins (PCDDs) proceeded with a high efficiency of 91.5% even at room temperature (Example 9). Furthermore, the dechlorination reaction also proceeded for polychlorinated dibenzofurans (PCDFs) in 4.36 wt% to 9.61 wt% hydrous soil, and the decomposition rate of 61.4% was maintained (Examples 10 to 12). In both PCDDs and PCDFs, the decomposition by dechlorination reaction was promoted on the polychlorinated body side.

  Next, the contaminated soil containing 1060 μg to 2850 μg of PCBs in 10 g of soil was treated in the same manner, and a decomposition rate of 96.2 to 99.9% was achieved (Examples 13 to 15). In addition, a high decomposition rate was achieved in each component of coplanar PCBs (Example 16). A dechlorination efficiency of 61.3% was achieved only by stirring for 24 hours with a cylindrical rotating device (Example 17). For reference, it was also confirmed that dechlorination reaction using calcium oxide alone or unground metal Ca hardly progressed at room temperature.

  Furthermore, although the total water content of the 10 wt% water content soil is about 10 times mol of the amount of metal Ca used and about 3 times mol of CaO, nanoparticulate metal Ca has high dechlorination activity. Maintained.

Examples 18-24, Comparative Example 3
Commercially available metal Ca (φ2.0-2.5 mm, 0.43-0.48 m ² / g) and CaO (825 ° C., dried for 2 hours) were mixed at a ratio of Ca / CaO = 1/5, and in an Ar atmosphere Then, pulverization was performed at 600 rpm for 1 hour using a planetary ball mill (manufactured by Fritsch: model P-7). The obtained pulverized mixture was observed with a scanning electron microscope (JEOL, 6510ASEM-EDS). The amount of metallic Ca in the pulverized mixture was determined from the amount of hydrogen gas by the water displacement method. The soil moisture was measured according to JIS-Z7302-3, and the composition analysis was performed according to JIS-M8853 and M8855. The amount of metallic Ca in the pulverized mixture was approximately 2.8 mmol / g-mixture (11.2 wt% Ca / g-mixture). Observation with an electron microscope revealed that the particles were aggregates having a particle size of 50 nm or less, and maintained 80% or more of the initial activity for 1 month or more at room temperature in the atmosphere.

  PCBs-contaminated soil was treated at room temperature in the atmosphere using the metal Ca / CaO pulverized mixture (11.2 wt% Ca / g-mixture) prepared to the nano size. The ratio of the metal Ca / CaO pulverized mixture (11.2 wt% Ca / g-mixture) prepared to nanosize and PCBs-contaminated soil was 1 g: 9 g. The processing conditions and results are shown in Table 3. In Table 3, the amount of water is a value for PCBs-contaminated soil to which a metal Ca / CaO pulverized mixture is added. As Comparative Example 3, an experiment was conducted using only calcium oxide as a decomposition agent at room temperature in the atmosphere. The analysis procedure is the same as in Example 9. By using a metal Ca / CaO pulverized mixture prepared to a nano size, a high decomposition rate of 90% or more was achieved even at room temperature. The stirring and mixing operation was also performed by stirring for 1 hour with a mortar type stirring device, and a decomposition rate of 97% was achieved even after being left for 10 days (Example 23). On the other hand, when calcium oxide was used as the decomposing agent, PCBs were not decomposed at all.

Examples 25-40
Contamination of PCBs, PCDDs, and PCDFs at room temperature in the air using a metal Ca / CaO pulverized mixture (11.9 wt% Ca / g-mixture, 2.8 mmol) prepared in the same manner as in Example 18 The soil was treated. The ratio of the metal Ca / CaO pulverized mixture prepared in nanosize to the contaminated soil was 1 g: 9 g. Treatment conditions and results are shown in Tables 4-7. In Tables 4-7, the amount of water is a value for PCBs-contaminated soil to which a metal Ca / CaO pulverized mixture is added. As the stirrer, a mortar stirrer was used, and the mixture was stirred and mixed at room temperature for 24 hours. The analysis procedure is the same as in Example 9. By using a metal Ca / CaO pulverized mixture prepared in nano size, a high decomposition rate was achieved even at room temperature.

Claims (12)

A method of detoxifying the organic halogen compound by bringing a solid containing the organic halogen compound into contact with metal particles as an electron donor,
A method for detoxifying a solid containing an organic halogen compound, wherein at least a part of the metal particles are nano-sized particles, and the organic halogen compound is reduced and detoxified.   The metal particle is a mixture of a solid metal and a water adsorbing / desorbing agent for adsorbing / desorbing water having a moisture adjusting function and acting as a hydrogen source and / or a porous inorganic material, at least a part of the solid metal. 2. The organohalogen compound according to claim 1, wherein the organohalogen compound according to claim 1 is provided as a metal dispersion in which metal particles obtained by pulverization until a nano-size is dispersed in a water adsorption / desorption agent and / or a porous inorganic material A method for detoxifying contained solids.   In the metal dispersion, the surface of nano-sized metal particles is coated with the water adsorption / desorption agent and / or porous inorganic material, and the water adsorption / desorption agent and / or porous inorganic material is large in size of the nano-sized metal particles. 3. The method for detoxifying a solid containing an organic halogen compound according to claim 2, wherein the portion is prevented from coming into direct contact with oxygen, carbon dioxide or water.   In the treatment for detoxifying the organic halogen compound, the metal particles are obtained by pulverizing the solid containing the organic halogen compound and the solid metal so that at least a part of the solid metal is nano-sized. The method for detoxifying a solid containing an organic halogen compound according to claim 1, wherein   The solid containing an organic halogen compound according to claim 4, further comprising adding a water adsorption / desorption agent and / or a porous inorganic material, and simultaneously pulverizing the water adsorption / desorption agent and / or the porous inorganic material. Detoxification method.   6. The organic halogen compound is reduced and rendered harmless while stirring using a mill having a lower energy density in the mill as compared with a planetary ball mill without actively heating from the outside. A method for detoxifying a solid containing the organic halogen compound according to any one of the above.   The solid containing an organic halogen compound according to any one of claims 1 to 6, further comprising an alcohol and / or an organic acid as a hydrogen source coexisting to reduce and detoxify the organic halogen compound. Detoxification method. The solid containing the organic halogen compound is soil, incineration ash, incineration fly ash, sludge or a mixture thereof,
8. The organic according to claim 7, wherein the alcohol and / or organic acid is alcohol and / or organic acid contained in soil, incineration ash, incineration fly ash, sludge, or a mixture thereof. A method for detoxifying a solid containing a halogen compound.   When the amount of water contained in the solid containing the organic halogen compound exceeds a predetermined value, a moisture adjusting agent is added to the solid prior to the detoxification treatment of the organic halogen compound, and the amount of water contained in the solid The method for detoxifying a solid containing an organic halogen compound according to any one of claims 1 to 8, wherein the moisture is adjusted to a value not more than a predetermined value.   10. The metal particle according to claim 1, wherein the metal particles include at least one of an alkali metal, an alkaline earth metal, a Group 3 element, iron, zinc, and an alloy containing these. A method for detoxifying a solid containing an organic halogen compound.   The method for detoxifying a solid containing an organic halogen compound according to any one of claims 1 to 10, wherein the organic halogen compound is a residual organic pollutant and / or a volatile organic compound. Further, the adsorbent adsorbs the vapor of the volatile organic compound generated when detoxifying the organic halogen compound,
The adsorbent and metal particles as an electron donor are mechanochemically treated, or at least a part of the adsorbent and a protic solvent are dissolved and mixed with a metal having a reducing power by electron transfer and a protic solvent, The method for detoxifying a solid containing an organic halogen compound according to claim 11, comprising a step of detoxifying a volatile organic compound.