JP2019103991A - Decomposition processing method of chloroethylene in soil and groundwater - Google Patents
Decomposition processing method of chloroethylene in soil and groundwater Download PDFInfo
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本発明は、クロロエチレンで汚染された土壌中や、クロロエチレンで汚染された地下水中におけるクロロエチレンを分解処理して当該土壌や地下水を浄化する、土壌や地下水におけるクロロエチレンの分解処理方法に関する。 The present invention relates to a method for decomposing chloroethylene in soil or groundwater, which decomposes chloroethylene in chloroethylene-contaminated soil or in groundwater contaminated with chloroethylene to purify the soil or groundwater.
半導体工場や金属加工工場等において、脱脂溶剤として過去より多量に使用され、使用後排出されあるいは投棄されてきたトリクロロエチレン（本発明において「ＴＣＥ」と記載する場合がある。）等の有機塩素系化合物が、土壌または地下水を汚染した状態で蓄積され、工場跡地の再利用や周辺地域の土地開発に障害をもたらした事例がある。また、当該蓄積された有機塩素系化合物による地下水の汚染が、この地下水利用上の障害になる等、大きな社会問題となった事例もある。
このような有機塩素系化合物による汚染水を鉄系金属還元剤で処理し、汚染物質を分解させ無害化する方法について、例えば特許文献１〜５の提案がある。
Organochlorine compounds such as trichloroethylene (sometimes referred to as “TCE” in the present invention) that has been used as a degreasing solvent in large amounts as a degreasing solvent in semiconductor and metal processing plants and the like and has been discharged or discarded after use. However, there have been cases in which soil or groundwater has been accumulated, which has resulted in the reutilization of factory sites and the failure of land development in the surrounding area. In addition, there have been cases in which contamination of groundwater by the accumulated organic chlorine compounds has become a serious social problem, such as becoming an obstacle to the use of the groundwater.
For example, Patent Documents 1 to 5 have proposed the method of treating the polluted water with such an organic chlorine compound with an iron-based metal reducing agent to decompose the pollutant and make it harmless.
特許文献１に記載の方法は、被処理水即ち難分解性ハロゲン化炭化水素含有水を、ｐＨ６．５〜９．５に調整したのち、鉄等の卑金属系還元剤により還元処理する方法である。特許文献２に記載の方法は、有機化合物を含有する被処理水を金属系還元剤により無害化処理するにあたり、予め被処理水をｐＨ６．５以上とし、還元性物質により酸化還元電位を下げて酸化性物質を除去しておく方法である。特許文献３に記載の方法は、有機塩素系化合物を含有する汚染水に水素を供給して溶存酸素を除いた後、鉄等の金属を担持した活性炭等担体物質に接触させて還元処理を行う方法である。 The method described in Patent Document 1 is a method in which water to be treated, that is, water having low degradability halogenated hydrocarbon, is adjusted to pH 6.5 to 9.5 and then reduction treatment is performed with a base metal-based reducing agent such as iron. . In the method described in Patent Document 2, when water to be treated containing an organic compound is detoxified with a metal-based reducing agent, the water to be treated is previously adjusted to pH 6.5 or more, and the redox potential is lowered by a reducing substance. It is a method of removing oxidizing substances. The method described in Patent Document 3 supplies hydrogen to contaminated water containing an organic chlorine compound to remove dissolved oxygen, and then contacts a carrier material such as activated carbon carrying a metal such as iron to perform reduction treatment It is a method.
また、特許文献４に記載の方法は、ハロゲン有機汚染物質による汚染地下水の浄化方法として、酸素が遮断された環境の下で、汚染地下水を鉄粒子等金属体からなる透過性の地中層に通して汚染物質の分解を行わせる方法である。さらに、特許文献５記載の方法は、特許文献４の記載と同様の汚染地下水の浄化方法であって、汚染地下水を、地中に形成した活性炭等吸着物質と鉄ヤスリ屑等金属粒子からなる混合物による透過性の層を通過させることで、汚染物質の吸着・分解を行わせる方法である。 In the method described in Patent Document 4, as a method of purifying groundwater contaminated with a halogen organic contaminant, polluted groundwater is passed through a permeable underground layer made of a metal body such as iron particles under an environment in which oxygen is shut off. Decomposition of pollutants. Furthermore, the method described in Patent Document 5 is a method for purifying polluted groundwater similar to the method described in Patent Document 4 and is a mixture of activated carbon such as activated carbon formed in the ground and metal particles such as iron scrap and the like. Is a method of adsorbing and decomposing pollutants by passing through a permeable layer.
その他、汚染地下水の処理方法については、この汚染地下水を土壌外に抽出して無害化処理する真空抽出法や揚水曝気法等がある。また、汚染土壌の処理方法については、当該汚染土壌を掘削して加熱処理によって無害化する熱脱着法および熱分解法が知られている。さらに、土壌中や地下水中の汚染物質を分解して無害化する方法として、微生物を利用したバイオレメディエーション法による浄化法が知られている。 In addition, as a method for treating contaminated groundwater, there are a vacuum extraction method, a pumping-air aeration method, etc. for extracting the contaminated groundwater outside the soil and detoxifying it. Moreover, the thermal desorption method and thermal decomposition method of digging the said contaminated soil and detoxifying it by heat processing are known as a processing method of contaminated soil. Furthermore, as a method of decomposing and detoxifying pollutants in soil and groundwater, a purification method by a bioremediation method using microorganisms is known.
しかしながら、上述の浄化法では、平成２９年４月１日に土壌汚染対策法の第一種特定有害物質に加えられたクロロエチレン（本発明において「ＣＥ」と略記する場合がある。）に対する浄化効果の有無は不明であった。さらに、ＣＥはＴＣＥ等有機塩素系化合物の分解によって副生することが知られているが、その副生物としてのＣＥを浄化する効果についても不明であった。 However, in the above-mentioned purification method, purification on chloroethylene (sometimes abbreviated as "CE" in the present invention) added on April 1, 2017 to the Class 1 specified harmful substances of the Soil Contamination Countermeasures Law. The presence or absence of the effect was unknown. Furthermore, CE is known to by-produce by decomposition of organic chlorine compounds such as TCE, but the effect of purifying CE as a by-product was also unclear.
そこで、本発明は、ＣＥで汚染された土壌や地下水、土壌中や地下水中に存在したＴＣＥ等の有機塩素系化合物の分解によってＣＥが副生してしまった土壌や地下水へ、安価な鉄材を用いた還元剤を分散させることにより短期間でＣＥを分解処理し、土壌や地下水を浄化出来るクロロエチレンの分解処理方法の提供を目的とする。
尚、本発明における「土壌」とは、地下水水位以下の所謂、飽和帯の土壌のみならず、水で満たされていない地下水水位以上の不飽和帯の土壌、さらに、掘削後の土壌も含み、含水率が５質量％以上の土壌全般を示す概念である。
Therefore, the present invention provides an inexpensive iron material to soil and groundwater in which CE has been by-produced by decomposition of organochlorine compounds such as soil and groundwater contaminated with CE, and TCE and the like present in soil and groundwater. It is an object of the present invention to provide a decomposition treatment method of chloroethylene capable of decomposing CE in a short time by dispersing the used reducing agent, and purifying soil and groundwater.
In the present invention, “soil” in the present invention includes not only soil in the so-called saturated zone below the groundwater level, soil in the unsaturated zone above the groundwater level not filled with water, and soil after excavating, It is a concept showing the whole soil with a moisture content of 5% by mass or more.
本発明者は、前記課題を解決すべく鋭意検討を重ねた結果、上述したＣＥで汚染されていたり、ＣＥが副生してしまった土壌中や地下水中、さらには、当該土壌や地下水の近傍の土壌中や地下水中へ、本発明に係る銅含有鉄粉を分散させて鉄粉分散層を敷設し、当該鉄粉分散層内でＣＥを分解することにより前記課題が解決できることを知見し、本発明を完成するに至った。
尚、本発明において「近傍」とは、ＣＥやＴＣＥ等の有機塩素系化合物で汚染された土壌や地下水を含みＣＥの分解処理を行うと判断された領域の周囲領域のことである。そして概ね、当該分解処理を行うと判断された領域の周囲において設定した１０ｍ格子の領域以上、３０ｍ格子の領域以下の範囲のことである。
As a result of intensive studies to solve the above problems, the inventor of the present invention has found that it is contaminated with the above-mentioned CE or in the soil or groundwater in which the CE is by-produced, and further in the vicinity of the soil or groundwater. The copper-containing iron powder according to the present invention is dispersed in soil or underground water to lay an iron powder dispersion layer, and it is found that the above problems can be solved by decomposing CE in the iron powder dispersion layer, The present invention has been completed.
In the present invention, the term “proximal” refers to a peripheral region of a region that is determined to be subjected to CE decomposition processing, including soil and groundwater contaminated with organic chlorine compounds such as CE and TCE. And generally, it is a range of 10 m lattice area or more and 30 m lattice area or less set around the area determined to perform the decomposition process.
即ち、上述の課題を解決する為の第１の発明は、
クロロエチレンで汚染され含水率が５質量％以上の土壌中および／またはクロロエチレンで汚染された地下水中のクロロエチレンの分解処理方法であって、
前記土壌中および／または地下水中へ、銅含有鉄粉を分散させて鉄粉分散層を敷設し、前記鉄粉分散層において前記クロロエチレンを分解することを特徴とするクロロエチレンの分解処理方法である。
第２の発明は、
前記土壌中および／または地下水中へ前記銅含有鉄粉を分散させる際、前記クロロエチレンで汚染された土壌および／または地下水が存在する領域の近傍へも、前記銅含有鉄粉を分散させて鉄粉分散層を敷設することを特徴とする第１の発明に記載のクロロエチレンの分解処理方法である。
第３の発明は、
前記銅含有鉄粉が、０．１質量％以上２０質量％以下の銅を含有していることを特徴とする第１または第２の発明に記載のクロロエチレンの分解処理方法である。
第４の発明は、
前記土壌および／または地下水が、さらにシス−１，２−ジクロロエチレン（本発明において「ＤＣＥ」と記載する場合がある。）、トリクロロエチレンおよびテトラクロロエチレン（本発明において「ＰＣＥ」と記載する場合がある。）から選択される１種以上で汚染されていることを特徴とする第１から第３の発明のいずれかに記載のクロロエチレンの分解処理方法である。
第５の発明は、
前記銅含有鉄粉を、前記土壌中および／または地下水中へ０．１質量％以上１０質量％以下分散させることを特徴とする第１から第４の発明のいずれかに記載のクロロエチレンの分解処理方法である。
第６の発明は、
前記銅含有鉄粉を、前記土壌中および／または地下水中へ分散させる際、水溶性であって水中で弱酸性を示す還元性物質を、前記銅含有鉄粉と共に前記土壌中および／または地下水中へ分散させることを特徴とする第１から第５の発明のいずれかに記載のクロロエチレンの分解処理方法である。
第７の発明は、
前記水溶性であって水中で弱酸性を示す還元性物質を、前記土壌中および／または地下水中へ１００ｐｐｍ以上分散させることを特徴とする第６の発明に記載のクロロエチレンの分解処理方法である。
第８の発明は、
前記水溶性であって水中で弱酸性を示す還元性物質が、亜硫酸水素ナトリウム、二亜硫酸ナトリウムおよび亜ジチオン酸ナトリウムから選択される１種以上の化合物であることを特徴とする第６または第７の発明に記載のクロロエチレンの分解処理方法である。
第９の発明は、
前記鉄粉分散層のｐＨが３．５以上９以下であることを特徴とする第１から第８の発明のいずれに記載のクロロエチレンの分解処理方法である。
第１０の発明は、
前記クロロエチレンを分解する際、前記鉄粉分散層へ与熱して、前記鉄粉分散層を自然温度よりも昇温させることを特徴とする第１から第９の発明のいずれかに記載のクロロエチレンの分解処理方法である。
第１１の発明は、
前記鉄粉分散層への与熱には、無機化合物の化学反応熱、熱媒、またはジュール熱から選択される１種以上を用いることを特徴とする第１０の発明に記載のクロロエチレンの分解処理方法である。
That is, the first invention for solving the above-mentioned problems is:
A method for decomposing chloroethylene in a soil contaminated with chloroethylene and having a water content of 5% by mass or more and / or in groundwater contaminated with chloroethylene,
A copper-containing iron powder is dispersed in the soil and / or underground water to lay an iron powder dispersion layer, and the chlorine powder is decomposed in the iron powder dispersion layer. is there.
The second invention is
When dispersing the copper-containing iron powder in the soil and / or in the ground water, the copper-containing iron powder is also dispersed in the vicinity of the area where the chloroethylene-contaminated soil and / or the ground water is present. It is the decomposition treatment method of chloroethylene according to the first invention characterized by laying a powder dispersion layer.
The third invention is
The method for decomposing and treating chloroethylene according to the first or second aspect of the invention is characterized in that the copper-containing iron powder contains 0.1% by mass or more and 20% by mass or less of copper.
The fourth invention is
The soil and / or ground water may further be cis-1,2-dichloroethylene (sometimes described as "DCE" in the present invention), trichloroethylene and tetrachloroethylene (sometimes described as "PCE" in the present invention). It is contaminated with one or more sorts chosen from, The decomposition processing method of chloroethylene according to any one of the first to third inventions.
The fifth invention is
The decomposition of chloroethylene according to any one of the first to fourth inventions, wherein the copper-containing iron powder is dispersed in the soil and / or in the ground water at 0.1% by mass to 10% by mass. It is a processing method.
The sixth invention is
When the copper-containing iron powder is dispersed in the soil and / or in the ground water, a reducing substance that is water-soluble and shows weak acidity in water, and the copper-containing iron powder in the soil and / or underground water It is a method of decomposing treatment of chloroethylene according to any one of the first to fifth inventions, characterized in that it is dispersed in water.
The seventh invention is
It is the decomposition treatment method of chloroethylene according to the sixth invention, wherein the water-soluble reducing substance showing weak acidity in water is dispersed in the soil and / or ground water by 100 ppm or more. .
The eighth invention is
The sixth or seventh feature is that the reducing substance that is water-soluble and weakly acidic in water is one or more compounds selected from sodium bisulfite, sodium bisulfite and sodium dithionite. It is a method for decomposition treatment of chloroethylene according to the invention of
The ninth invention is
The pH of the iron powder dispersion layer is 3.5 or more and 9 or less, which is the method for decomposing and treating chloroethylene according to any of the first to eighth inventions.
The tenth invention is
In decomposing the chloroethylene, the iron powder dispersion layer is heated to raise the temperature of the iron powder dispersion layer above the natural temperature, and the chloroethylene according to any one of the first to ninth inventions. It is a decomposition treatment method of ethylene.
The eleventh invention is
The decomposition of chloroethylene according to the tenth invention is characterized in that at least one selected from the heat of chemical reaction of an inorganic compound, a heat medium, or Joule heat is used for applying heat to the iron powder dispersion layer. It is a processing method.
本発明によれば、ＣＥに汚染された土壌や地下水を短期間で浄化出来る。 According to the present invention, soil and groundwater contaminated with CE can be cleaned in a short time.
本発明は、ＣＥで汚染された土壌や地下水、土壌中や地下水中に存在したＴＣＥ等の有機塩素系化合物の分解によってＣＥが副生してしまった土壌や地下水へ、安価な鉄材である銅含有鉄粉を用いた還元剤を分散させて鉄粉分散層を敷設し、当該鉄粉分散層において前記ＣＥを分解することにより短期間でＣＥを分解処理し、土壌や地下水を浄化出来るＣＥの分解処理方法である。
以下、本発明を実施するための形態について、［１］銅含有鉄粉、［２］土壌への銅含有鉄粉の添加方法、［３］鉄粉分散層への与熱方法、［４］効果、の順に説明する。
The present invention relates to copper, which is an inexpensive iron material, to soil and groundwater in which CE has been by-produced by decomposition of organochlorine compounds such as soil and groundwater contaminated with CE, and TCE and the like present in the soil and groundwater. An iron powder dispersion layer is formed by dispersing a reducing agent using iron powder containing iron powder, and the CE powder can be decomposed in a short period of time by decomposing the CE in the iron powder dispersion layer to purify soil and groundwater. It is a decomposition processing method.
Hereinafter, with respect to embodiments for carrying out the present invention, [1] copper-containing iron powder, [2] method of adding copper-containing iron powder to soil, [3] method of applying heat to iron powder dispersion layer, [4] The effects will be described in order.
［１］銅含有鉄粉
本発明に係る銅含有鉄粉に用いる鉄粉は、炭素含有量が０．１質量％以上である殆どの普通鋼成分および普通鋳鉄成分のものが含まれる。これは、炭素含有量が０．１質量％であるとＣＥの分解速度を担保出来、実用的であることにより、炭素含有量が１質量％以上である鉄粉は、さらに好適である。
また、鉄粉の粒度は目開き１５０μｍのふるいを全体の５０質量％以上が通過するように調整されたものを用いることが好ましい。当該粒度およびより細かい粒度の鉄粉を用いることにより、汚染物質の分解速度が担保出来ると共に、鉄粉の利用効率も担保出来、鉄粉添加量の増加を回避出来、経済的に好ましいからである。
[1] Copper-Containing Iron Powder The iron powder used for the copper-containing iron powder according to the present invention includes most ordinary steel components and ordinary cast iron components having a carbon content of 0.1% by mass or more. It is possible to ensure the decomposition rate of CE when the carbon content is 0.1% by mass, and it is practical that iron powder having a carbon content of 1% by mass or more is more preferable.
Moreover, it is preferable to use what the particle size of the iron powder adjusted so that 50 mass% or more of the whole might pass through a 150-micrometer sieve. By using the iron powder of the particle size and the finer particle size, it is possible to secure the decomposition rate of the contaminants and also secure the utilization efficiency of the iron powder and to avoid an increase in the amount of iron powder added, which is economically preferable. .
土壌および地下水に添加し、鉄粉分散層を敷設する銅含有鉄粉として、汚染物質との接触面積を大として反応効率を高める観点から、比表面積が５００ｃｍ２／ｇ以上、好ましくは２０００ｍ２／ｇ以上の鉄粉を用いることが好ましい。また、当該鉄粉は、汚染物質との反応性を高める観点から、結晶成長度が低く、結晶構造としてパーライト組織が存在するものが好ましい。そして、当該鉄粉は、比較的安価な鉄材を用いた還元剤であり、短期間で汚染物質を分解して浄化出来る。 A copper-containing iron powder to be added to soil and ground water to lay an iron powder dispersion layer, from the viewpoint of increasing the reaction efficiency by increasing the contact area with contaminants, the specific surface area is 500 cm 2 / g or more, preferably 2000 m 2 / It is preferable to use iron powder of g or more. Further, from the viewpoint of enhancing the reactivity with the contaminant, the iron powder preferably has a low degree of crystal growth, and a pearlite structure is present as a crystal structure. And the said iron powder is a reducing agent using a comparatively cheap iron material, and can decompose | disassemble and purify | clean a contaminant in a short time.
本発明に係る銅含有鉄粉は、例えば、上述した鉄粉を、硫酸銅水溶液等の銅イオンを含む溶液中に混合し、得られた沈澱物を回収することによって容易に調製される。
銅含有鉄粉の銅含有率は０．１〜２０質量％の範囲内とするのが好ましい。これは、銅含有率が０．１質量％より大きい場合、ＣＥの分解速度に顕著な効果を期待出来、銅含有率が２０質量％以下であれば当該銅含有鉄粉の原価を抑制出来、経済的に好ましいからである。
The copper-containing iron powder according to the present invention is easily prepared, for example, by mixing the above-mentioned iron powder in a solution containing copper ions such as a copper sulfate aqueous solution, and recovering the obtained precipitate.
The copper content of the copper-containing iron powder is preferably in the range of 0.1 to 20% by mass. This is because when the copper content is greater than 0.1% by mass, a significant effect can be expected on the decomposition rate of CE, and when the copper content is 20% by mass or less, the cost of the copper-containing iron powder can be suppressed. It is because it is economically preferable.
［２］土壌および地下水への銅含有鉄粉の添加方法
本発明に係る銅含有鉄粉は、地下水水位以下の所謂、飽和帯の土壌のみならず、水で満たされていない地下水水位以上の不飽和帯の土壌さらに掘削後の土壌を含む、含水率が５質量％以上の土壌全般および当該土壌中の水分、および地下水において還元作用を発揮し、ＣＥを分解すると考えられる。
そして、上記土壌および地下水への銅含有鉄粉の添加量は、土壌および地下水の湿重量に対して０．１〜１０質量％の範囲とすることが好ましい。これは、鉄粉を０．１質量％以上添加すれば、ＣＥの分解速度が担保出来、１０質量％以下の添加であれば経済的に好ましいからである。
[2] Method of Adding Copper-Containing Iron Powder to Soil and Groundwater The copper-containing iron powder according to the present invention is not only soil of the so-called saturated zone below the groundwater level, but not above the groundwater level not filled with water. It is thought that it exerts a reducing action on general soils with a moisture content of 5% by mass or more, including the soil in the saturated zone and the soil after excavating, and the water in the soil, and groundwater, to decompose CE.
And it is preferable that the addition amount of copper containing iron powder to the said soil and groundwater sets the range of 0.1-10 mass% with respect to the wet weight of soil and groundwater. This is because addition of 0.1% by mass or more of iron powder can ensure the decomposition rate of CE, and addition of 10% by mass or less is economically preferable.
本発明に係る銅含有鉄粉を、ＣＥで汚染された土壌中および／または地下水中へ分散させて鉄粉分散層を敷設する。この鉄粉分散層を敷設する際、当該ＣＥで汚染された土壌および／または地下水が存在する領域、さらに好ましくは当該領域の近傍へも、前記銅含有鉄粉を分散させて鉄粉分散層を敷設する。 The copper-containing iron powder according to the present invention is dispersed in CE-contaminated soil and / or underground water to lay an iron powder dispersion layer. When laying the iron powder dispersion layer, the iron powder dispersion layer is dispersed by dispersing the copper-containing iron powder in a region where the soil and / or ground water contaminated with the CE is present, more preferably in the vicinity of the region. Lay down.
さらに、上述した銅含有鉄粉の還元反応を効果的に促進する観点から、水溶性であって水中で弱酸性を示す還元性物質を、前記銅含有鉄粉と共に汚染された土壌および地下水へ添加することも好ましい構成である。
当該水溶性であって水中で弱酸性を示す還元性物質は具体的には、亜硫酸水素ナトリウム、二亜硫酸ナトリウムおよび亜ジチオン酸ナトリウムから選択される１種以上の化合物を好ましく挙げることが出来る。そして、前記土壌および地下水中およびその近傍の土壌および地下水中へ１００ｐｐｍ以上分散させることが好ましい。
そして、鉄粉分散層のｐＨは３．５以上９以下であることが好ましい。
Furthermore, from the viewpoint of effectively promoting the reduction reaction of the copper-containing iron powder described above, a water-soluble reducing substance that exhibits weak acidity in water is added to the soil and groundwater contaminated with the copper-containing iron powder. Is also a preferred configuration.
Specific examples of the reducing substance that is water-soluble and weakly acidic in water can specifically include one or more compounds selected from sodium bisulfite, sodium bisulfite and sodium dithionite. And it is preferable to disperse | distribute 100 ppm or more to the said soil and underground water, and the soil and underground water of that vicinity.
The pH of the iron powder dispersion layer is preferably 3.5 or more and 9 or less.
本発明に係る銅含有鉄粉を土壌および地下水に添加して混合し分散させて、鉄粉分散層を敷設するには、原位置処理の場合においては、空気または水等による高圧媒体を利用して地中に散布する方法、または土壌の場合は地盤改良工事で利用される土木機械を用いて機械的に掘削混合する方法を採ることが出来る。
一方、土壌に掘削混合する方法においては、ニーダー、ミキサー、ブレンダー等の混合装置の利用も可能である。特に、掘削する土壌が粘土質等で流動性が低い場合、数個の軸を持つ回転するハンマーによる打撃式混合方法が好ましい。
In the case of in-situ treatment, a copper-containing iron powder according to the present invention is added to, mixed with, and dispersed in soil and groundwater to use a high pressure medium such as air or water in the case of in-situ treatment. In the case of soil, it is possible to adopt a method of mechanically digging and mixing using a civil engineering machine used for ground improvement work.
On the other hand, in the method of digging and mixing in soil, it is also possible to use a mixing device such as a kneader, a mixer, or a blender. In particular, when the soil to be excavated is clay or the like and has low fluidity, a hammer-type mixing method using a rotating hammer having several axes is preferable.
尚、鉄粉は、表面が酸化されることで徐々に不活性化して反応力が低下する。そこで、鉄粉による汚染物質の分解作用を担保する為に、鉄粉を混合した後の土壌に対して新たな酸素あるいは酸化性物質の供給が行われないよう留意することが好ましい。具体的には、原位置処理や土壌の掘削後処理において鉄粉分散層を敷設後に、土壌および地下水表面が新たな外気と直接接触しないように留意することが好ましい。 The iron powder is gradually inactivated by oxidation of the surface and the reaction power is reduced. Therefore, in order to secure the decomposing effect of the iron powder on pollutants, it is preferable to be careful not to supply new oxygen or oxidizing substance to the soil after the iron powder is mixed. Specifically, it is preferable to keep in mind that the soil and groundwater surface do not directly contact with fresh outside air after laying the iron powder dispersion layer in the in-situ treatment and after the excavating treatment of the soil.
［３］鉄粉分散層への与熱方法
本発明者らは、本発明に係る銅含有鉄粉による汚染土壌および地下水の浄化を目標にして、土壌および地下水中のＣＥを初めとする有機塩素系化合物の効果的な分解除去法を確立すべく種々の試験研究を重ねてきた。そして、本発明に係る銅含有鉄粉を土壌および地下水に添加して混合し分散させて敷設した鉄粉分散層へ付熱して、当該鉄粉分散層を自然温度よりも昇温させることにより、ＣＥを初めとする有機塩素系化合物の分解が著しく促進されることを知見した。
[3] Method of applying heat to iron powder dispersed layer The present inventors set organic chlorine including CE in soil and groundwater aiming at purification of contaminated soil and groundwater by copper-containing iron powder according to the present invention. Various experimental studies have been conducted to establish an effective decomposition and removal method of the compound. Then, the copper powder-containing iron powder according to the present invention is added to the soil and the ground water, mixed, dispersed and heated to heat the iron powder dispersion layer, thereby raising the temperature of the iron powder dispersion layer above natural temperature; It has been found that the decomposition of organochlorine compounds including CE is significantly promoted.
そして、当該鉄粉分散層への与熱は、無機化合物の中和熱・水和熱・その他の化学反応熱を利用すれば比較的簡単、且つ、無害に行えることも明らかとなった。
結局のところ、鉄粉分散層への与熱手段としては、発熱を起こす無機化合物を単独または組み合わせて、当該汚染土壌に添加して混合するのが最も簡易である。
例えば、中和熱を利用する場合には、酸性化合物と塩基性化合物とを添加して無害な塩を生成させればよい。このような単独または組み合わせて使用する酸性無機化合物としては、鉱酸である硫酸、塩酸、硝酸、リン酸等が好ましく、塩基性無機化合物としては、生石灰、消石灰、水酸化ナトリウム、炭酸ナトリウム、炭酸カルシウム等が好ましい。
また例えば、水和熱を利用する場合には、生石灰等の水和反応熱を生成する無機化合物を添加すればよい。
It has also been revealed that heat application to the iron powder dispersion layer can be carried out relatively easily and harmlessly by utilizing heat of neutralization, heat of hydration and other chemical reaction of the inorganic compound.
After all, as the means for heating the iron powder dispersion layer, it is easiest to add an inorganic compound that generates heat alone or in combination to the contaminated soil and mix it.
For example, when using the heat of neutralization, an acid compound and a basic compound may be added to form a harmless salt. As such an acidic inorganic compound used singly or in combination, mineral acids such as sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid are preferable, and as a basic inorganic compound, quick lime, slaked lime, sodium hydroxide, sodium carbonate, carbonate Calcium and the like are preferred.
Also, for example, in the case of using the heat of hydration, an inorganic compound such as quicklime that generates heat of hydration reaction may be added.
上述したように、無機化合物をその種類によって水溶液の形態もしくは固体の状態で鉄粉分散層に添加することによって、鉄粉分散層の温度を自然温度より高く維持させることができる。また、固体状態のものは、その添加の前または後にさらに水を添加することによって、鉄粉分散層の温度を自然温度より高く維持させることができる。 As described above, the temperature of the iron powder dispersion layer can be maintained higher than the natural temperature by adding the inorganic compound to the iron powder dispersion layer in the form of an aqueous solution or in a solid state depending on the type. Also, in the solid state, the temperature of the iron powder dispersion layer can be maintained higher than the natural temperature by further adding water before or after the addition.
上述した鉄粉分散層への他の与熱手段としては、熱媒またはジュール熱も利用できる。熱媒としては昇温された水またはそれらの複合体（温水、熱水、等）を用いるのが経済的である。これらを直接的に土壌および地下水中に供給して鉄粉分散層を昇温させることもできるし、熱交換パイプを敷設し、その中に当該熱媒を通して、鉄粉分散層ヘ熱を供給させるようにしてもよい。ジュール熱を利用する場合には、温室栽培で利用されているように、通電により発熱する発熱マットや電熱線を鉄粉分散層中に敷設するのが便宜である。 A heat transfer medium or Joule heat can also be used as another means for heating the iron powder dispersion layer described above. It is economical to use heated water or a complex thereof (hot water, hot water, etc.) as the heat medium. These can be supplied directly to soil and groundwater to raise the temperature of the iron powder dispersion layer, or a heat exchange pipe can be laid, and heat can be supplied to the iron powder dispersion layer through the heat medium. You may do so. When Joule heat is used, it is convenient to lay a heating mat or a heating wire which generates heat by energization in the iron powder dispersion layer, as used in greenhouse cultivation.
［４］効果
以上説明した、本発明の実施に係る土壌および地下水処理を行うことにより、２〜３か月の処理期間で、日本における土壌汚染に係る環境基準（平成３年８月２３日環告、改正、平５環告１９、平６環告５・環告２５、平成７年環告１９、平成１０環告２１、平成１３環告１６、平成２０環告４６、平成２２環告３７、平成２６環告４４、平成２８環告３０）以下迄、土壌および地下水を浄化し無害化することが出来る。
[4] Effects By performing the soil and groundwater treatment according to the present invention as described above, the environmental standard for soil contamination in Japan in a treatment period of 2 to 3 months (August 23, 1991 Notification, Amendment, 5th Anniversary 19th, 6th Anniversary 5th, 25th Anniversary, 7th Anniversary 19th, Heisei 10th Anniversary 21, Heisei 13th Anniversary 16, Heisei 20th Anniversary 46, Heisei 22nd Notification 37 46, Heisei 28 (Heisei 28) 30) or less, it is possible to purify and detoxify soil, soil and groundwater.
以下、実施例を参照しながら本発明をより具体的に説明する。但し、本発明は当該実施例に限定される訳ではない。 Hereinafter, the present invention will be more specifically described with reference to examples. However, the present invention is not limited to the embodiment.
［実施例１］
実施例１に係る試験の操作方法を、図１を参照しながら説明する。
１２０ｍｌバイアル瓶に、純水５０ｍｌと、鉄粉として銅含有鉄粉（ＤＯＷＡ ＩＰクリエイション（株）製、Ｅ−４０１）１質量％とを投入して混合し、鉄粉を分散させた。当該バイアル瓶をＮ２ガスでパージ後，テフロンシール付きシリコン栓およびアルミキャップで密栓した。そして、ＣＥ標準１％ガス４．５ｍＬをシリンジで注入した。
当該バイアル瓶を常温で保管し、保管開始から０日目、３日目、７日目、１４日目、２１日目、２８日目毎に、ヘッドスペース中のＣＥガス濃度を測定した。
ＣＥガス濃度測定には、ＧＣ−８６１０（ＪＥＯＬ製）を用い、ＤＥＬＣＤ検出器にてガス濃度を測定した。当該測定結果を図２のグラフにおいて実線で示す。
図２より、ＣＥが銅含有鉄粉により分解され、２１日には溶出量基準値０．００２ｍｇ／Ｌ未満となり浄化が達成されたことが判明した。
尚、上述した銅含有鉄粉（Ｅ−４０１）は、還元鉄粉（ＤＯＷＡ ＩＰクリエイション（株）製、ロータリーキルン粉）５００ｇと、事前に２００℃空気気流中にて２ｈｒの熱処理を行い結晶水の脱水処理を行った硫酸銅（１水塩）粉１４．０ｇとを回転ボールミルに装入し、乾式で機械混合して両粉の粒子を接合させて得たポーラス状銅含有鉄粉である。
Example 1
The test operation method according to the first embodiment will be described with reference to FIG.
In a 120 ml vial, 50 ml of pure water and 1% by mass of copper-containing iron powder (DOWA IP Creation Co., Ltd. E-401) as iron powder were added and mixed to disperse the iron powder. The vial was purged with N 2 gas, and then sealed with a Teflon-sealed silicon plug and an aluminum cap. Then, 4.5 mL of CE standard 1% gas was injected by a syringe.
The vial was stored at normal temperature, and the CE gas concentration in the head space was measured every 0, 3, 7, 14, 14, 21 and 28 days after the start of storage.
For the measurement of the CE gas concentration, the gas concentration was measured with a DELCD detector using GC-8610 (manufactured by JEOL). The said measurement result is shown as a continuous line in the graph of FIG.
From FIG. 2, it was found that CE was decomposed by the copper-containing iron powder, and on the 21st day, the dissolution amount reference value was less than 0.002 mg / L and purification was achieved.
In addition, the copper-containing iron powder (E-401) mentioned above is heat treated for 2 hours in an air stream at 200 ° C. in advance with 500 g of reduced iron powder (Rotary Kiln powder manufactured by Dowa IP Creation Co., Ltd.) It is a porous copper-containing iron powder obtained by charging 14.0 g of copper sulfate (monohydrate salt) powder subjected to dehydration treatment to a rotary ball mill and mechanically mixing them in a dry state to join particles of both powders.
［比較例１］
鉄粉として、海綿状鉄粉（ＤＯＷＡ ＩＰクリエイション（株）製、Ｅ−２００）を使用した以外は、実施例１と同様の試験を行った。
測定結果を図２のグラフにおいて長破線で示す。
図２より、ＣＥは海綿状鉄粉により１４日から分解が始まったが、２８日時点では基準値を超過して残存していることが判明した。
Comparative Example 1
The same test as in Example 1 was conducted except that sponge iron powder (E-200 manufactured by Dowa IP Creation Co., Ltd.) was used as the iron powder.
The measurement results are shown by long dashed lines in the graph of FIG.
From FIG. 2, it was found that CE began to be decomposed from 14 days by cancellous iron powder, but by 28 days it remained above the reference value and remained.
［比較例２］
鉄粉として、アトマイズ鉄粉（和光純薬工業（株）製）を使用した以外は、実施例１と同様の試験を行った。
測定結果を図２のグラフにおいて短破線で示す。
図２より、ＣＥはアトマイズ鉄粉により１４日から分解が始まったが、２８日時点では基準値を超過して残存していることが判明した。
Comparative Example 2
The same test as in Example 1 was conducted except that atomized iron powder (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the iron powder.
The measurement results are shown by short dashed lines in the graph of FIG.
From FIG. 2, it was found that CE began to be decomposed from atomized iron powder from 14 days, but at 28 days it remained above the reference value and remained.
［実施例２］
実施例１にて用いたＣＥ標準１％ガス４．５ｍｌを、ＤＣＥ０．２μＬに置き換えた以外は、実施例１と同様の試験を行った。
尚、ＤＣＥ濃度はＧＣ−８６１０（ＪＥＯＬ製）、ＰＩＤ検出器にて測定した。
測定結果を図３、４のグラフにおいて実線で示す。但し、図３はＤＣＥ濃度の経時変化、図４はＤＣＥの分解により副生したＣＥ濃度の経時変化を示すグラフである。
図３より、ＤＣＥ濃度は銅含有鉄粉により７日で基準値０．０４ｍｇ／Ｌ未満になり、浄化が達成されたことが判明した。一方、図４より、ＣＥ濃度は７日まで増加していることから、ＤＣＥの分解によりＣＥが副生されたと考えられる。しかしＣＥはその後分解されて、１４日には基準値未満となり、浄化が達成されたことが判明した。
Example 2
The same test as in Example 1 was conducted, except that 4.5 ml of the CE standard 1% gas used in Example 1 was replaced with 0.2 μL of DCE.
The DCE concentration was measured using a GC-8610 (manufactured by JEOL) and a PID detector.
The measurement results are shown by solid lines in the graphs of FIGS. However, FIG. 3 is a graph showing temporal changes in DCE concentration, and FIG. 4 is a graph showing temporal changes in CE concentration by-produced by decomposition of DCE.
From FIG. 3, it was found that the DCE concentration was less than the reference value 0.04 mg / L in 7 days by the copper-containing iron powder, and the purification was achieved. On the other hand, as shown in FIG. 4, since the concentration of CE increased up to 7 days, it is considered that CE was by-produced by the decomposition of DCE. However, the CE was subsequently degraded and reached below the reference value on the 14th, and it was found that purification was achieved.
［比較例３］
鉄粉として、海綿状鉄粉（ＤＯＷＡ ＩＰクリエイション（株）製、Ｅ−２００）を使用した以外は、実施例２と同様の試験を行った。
測定結果を図３、４のグラフにおいて長破線で示す。
図３より、ＤＣＥは海綿状鉄粉により分解され徐々に減少し、２８日時点では０．１７ｍｇ／Ｌであることが判明した。一方、図４より、ＣＥ濃度は１４日目まで増加し、その後は２１日目まで減少したが、２８日時点では基準値を超えて残存していることが判明した。
Comparative Example 3
The same test as in Example 2 was conducted except that sponge iron powder (E-200 manufactured by Dowa IP Creation Co., Ltd.) was used as the iron powder.
The measurement results are shown by long broken lines in the graphs of FIGS.
From FIG. 3, it was found that DCE was decomposed and gradually decreased by cancellous iron powder, and was 0.17 mg / L at 28 days. On the other hand, FIG. 4 shows that the concentration of CE increased to the 14th day and then decreased to the 21st day, but remained at the 28th day beyond the reference value.
［比較例４］
鉄粉として、アトマイズ鉄粉（和光純薬工業（株）製）を使用した以外は、実施例２と同様の試験を行った。
測定結果を図３、４のグラフにおいて短破線で示す。
図３より、ＤＣＥはアトマイズ鉄粉により分解されているが、２８日時点では基準値を超えて残存していることが判明した。一方、図４より、ＣＥは７日目から増加していき、２８日時点では基準値を超えて残存していることが判明した。
Comparative Example 4
The same test as in Example 2 was conducted except that atomized iron powder (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the iron powder.
The measurement results are shown by short dashed lines in the graphs of FIGS.
From FIG. 3, it was found that DCE was decomposed by the atomized iron powder, but remained at the 28th day beyond the reference value. On the other hand, FIG. 4 shows that CE increased from the seventh day and remained above the reference value at the 28th day.
［実施例３］
実施例１にて用いたＣＥ標準１％ガス４．５ｍＬを、ＴＣＥ０．２μＬに置き換えた以外は、実施例１と同様の試験を行った。
尚、ＴＣＥ濃度はＧＣ−８６１０（ＪＥＯＬ製）、ＰＩＤ検出器にて測定した。
測定結果を図５〜７のグラフにおいて実線で示す。但し、図５はＴＣＥ濃度の経時変化、図６はＴＣＥの分解により副生したＤＣＥ濃度の経時変化、図７はＤＣＥの分解により副生したＣＥ濃度の経時変化を示すグラフである。
図５より、ＴＣＥは銅含有鉄粉により１４日で基準値０．０３ｍｇ／Ｌ未満になり、浄化が達成されたことが判明した。また、図６より、ＤＣＥは全日で検出されなかったことから、銅含有鉄粉ではＴＣＥからＤＣＥの副生はない、または、検出限界値未満と微量であることが考えられた。さらに、図７より、ＣＥもＤＣＥと同様に、全日で検出されなかった。
以上のことから、銅含有鉄粉ではＴＣＥが、ＤＣＥおよびＣＥを副生させない、またはこれらの発生量を検出限界値より少ない微量に抑制さながら分解されたと考えられる。
[Example 3]
The same test as in Example 1 was conducted except that 4.5 mL of the CE standard 1% gas used in Example 1 was replaced with 0.2 μL of TCE.
The TCE concentration was measured with a GC-8610 (manufactured by JEOL) and a PID detector.
The measurement results are shown by solid lines in the graphs of FIGS. However, FIG. 5 is a graph showing temporal change of TCE concentration, FIG. 6 is temporal change of DCE concentration by-produced by TCE decomposition, and FIG. 7 is temporal change of CE concentration by-produced by DCE decomposition.
From FIG. 5, it was found that TCE was less than the reference value of 0.03 mg / L in 14 days by copper-containing iron powder, and purification was achieved. Further, as shown in FIG. 6, since DCE was not detected on all days, it was considered that copper-containing iron powder had no by-products from TCE to DCE or was a trace amount of less than the detection limit value. Furthermore, as shown in FIG. 7, CE was not detected on all days, like DCE.
From the above, it is considered that in copper-containing iron powder, TCE is decomposed while DCE and CE are not by-produced, or the amount of generation thereof is suppressed to a trace amount smaller than the detection limit value.
［比較例５］
鉄粉として、海綿状鉄粉（ＤＯＷＡ ＩＰクリエイション（株）製、Ｅ−２００）を使用した以外は、実施例３と同様の試験を行った。
測定結果を図５〜７のグラフにおいて長破線で示す。
図５より、ＴＣＥは海綿状鉄粉により分解し、２８日時点では基準値未満になり浄化が達成されたことが判明した。図６より、ＤＣＥは７日まで増加し、その後分解されたことが判明した。図７より、ＣＥは１４日目まで増加し、その後は減少したがほぼ横ばいであった。そして、２８日時点では基準値を超えて残存していることが判明した。
以上のことから、海綿状鉄粉では、ＴＣＥからＤＣＥが副生され、さらにＤＣＥからＣＥが副生されることで、ＣＥの浄化が未達になる可能性が考えられた。
Comparative Example 5
The same test as in Example 3 was conducted, except that spongy iron powder (E-200, manufactured by Dowa IP Creation Co., Ltd.) was used as the iron powder.
The measurement results are shown by long broken lines in the graphs of FIGS.
From FIG. 5, it was found that TCE was decomposed by cancellous iron powder and became lower than the reference value at 28 days, and purification was achieved. From FIG. 6, it was found that DCE increased up to 7 days and then was degraded. From FIG. 7, CE increased to the 14th day, and decreased almost thereafter. And it turned out that it remained beyond the standard value as of 28th.
From the above, it is considered that in the case of cancellous iron powder, DCE is by-produced from TCE, and further, CE may be by-produced from DCE, so that purification of CE may not be achieved.
［比較例６］
鉄粉として、アトマイズ鉄粉（和光純薬工業（株）製）を使用した以外は、実施例３と同様の試験を行った。
測定結果を図５〜７のグラフにおいて短破線で示す。
図５より、ＴＣＥはアトマイズ鉄粉により分解されているが、分解速度が他の鉄粉に比べ遅く、２８日時点では基準値を超えて残存していることが判明した。図６より、ＤＣＥは７日目から２８日目時点まで増加しており、基準値を超えて残存していることが判明した。図７より、ＣＥは全日で検出されなかった。
以上のことから、ＴＣＥはアトマイズ鉄粉により分解されるが、分解速度は銅含有鉄粉に比べ遅いことが判明した。また、ＴＣＥからＤＣＥが副生され、２８日では分解せずに残存した。そして、当該ＤＣＥが分解されない為、ＣＥの副生はないと考えられた。
Comparative Example 6
The same test as in Example 3 was conducted except that atomized iron powder (manufactured by Wako Pure Chemical Industries, Ltd.) was used as iron powder.
The measurement results are shown by short dashed lines in the graphs of FIGS.
From FIG. 5, it was found that although TCE is decomposed by atomized iron powder, the decomposition rate is slower than other iron powders and remains above the standard value at 28 days. From FIG. 6, it was found that DCE increased from the 7th day to the 28th day, and remained above the reference value. From FIG. 7, CE was not detected in all days.
From the above, it was found that TCE is decomposed by atomized iron powder, but the decomposition rate is slower than copper-containing iron powder. In addition, DCE was by-produced from TCE and remained without decomposition at 28 days. And since the said DCE was not decomposed | disassembled, it was thought that there was no byproduct of CE.
［実施例４］
上述した実施例１、実施例２および実施例３において、銅含有鉄粉が純水中のＣＥを、副生物質も含めて浄化を達成出来ることを確認した。そこで本実施例では、当該銅含有鉄粉が土壌中のＣＥを浄化可能であるかを確認した。
Example 4
In Examples 1 and 2 and Example 3 described above, it was confirmed that the copper-containing iron powder can achieve purification of CE in pure water, including by-products. So, in the present Example, it confirmed whether the said copper containing iron powder can purify | clean CE in soil.
実施例４に係る試験の操作方法を、図８を参照しながら説明する。
１２０ｍｌバイアル瓶に、土壌１０ｇと、鉄粉として銅含有鉄粉（ＤＯＷＡ ＩＰクリエイション（株）製、Ｅ−４０１）１質量％とを投入して混合し、土壌中に鉄粉を分散させた。なお、使用した土壌は砂質土壌、含水率２０質量％、ｐＨ６．５であった。
当該バイアル瓶をＮ２ガスでパージ後，テフロンシール付きシリコン栓およびアルミキャップで密栓した。そして、ＣＥ標準１％ガス４．５ｍＬをシリンジで注入した。
当該バイアル瓶を常温で保管し、保管開始から０日目、３日目、７日目、１４日目、２１日目、２８日目毎に、ヘッドスペース中のＣＥガス濃度を測定した。
ＣＥガス濃度測定には、ＧＣ−８６１０（ＪＥＯＬ製）を用い、ＤＥＬＣＤ検出器にてガス濃度を測定した。
ヘッドスペースガスと土壌中とに同量でＣＥが存在すると仮定し、溶出量換算して濃度を算出した。
測定結果を図９のグラフにおいて短破線で示す。
図９より、ＣＥは銅含有鉄粉により分解され、２１日には基準値未満になり浄化が達成したことが判明した。
A test operation method according to the fourth embodiment will be described with reference to FIG.
In a 120 ml vial, 10 g of soil and 1 mass% of copper-containing iron powder (E-401 manufactured by Dowa IP Creation Co., Ltd.) as iron powder were added and mixed to disperse iron powder in the soil. The soil used was sandy soil, water content was 20% by mass, and pH was 6.5.
The vial was purged with N 2 gas, and then sealed with a Teflon-sealed silicon plug and an aluminum cap. Then, 4.5 mL of CE standard 1% gas was injected by a syringe.
The vial was stored at normal temperature, and the CE gas concentration in the head space was measured every 0, 3, 7, 14, 14, 21 and 28 days after the start of storage.
For the measurement of the CE gas concentration, the gas concentration was measured with a DELCD detector using GC-8610 (manufactured by JEOL).
Assuming that CE exists in the same amount in the head space gas and in the soil, the concentration is calculated by converting it into the elution amount.
The measurement results are shown by short dashed lines in the graph of FIG.
From FIG. 9, it was found that CE was decomposed by the copper-containing iron powder and became less than the reference value on the 21st, and purification was achieved.
[実施例５]
実施例４のＣＥ標準１％ガス４．５ｍＬをＤＣＥ０．２μＬに置き換えた以外は、実施例４と同様の試験を行った。
尚、ＤＣＥ濃度はＧＣ−８６１０（ＪＥＯＬ製）、ＰＩＤ検出器にて測定した。
測定結果を図１０に長破線で示す。但し、図１０中の長破線はＤＣＥ溶出量、短破線はＤＣＥの分解により副生したＣＥ溶出量である。
図１０より、ＤＣＥ溶出量は銅含有鉄粉により７日で基準値未満になり、浄化が達成された。ＣＥは３日まで増加していることから、ＤＣＥの分解により副生されたと考えられる。しかしＣＥはその後分解されて、７日には基準値未満となり、浄化が達成したことが判明した。
[Example 5]
The same test as in Example 4 was conducted, except that 4.5 mL of the CE standard 1% gas in Example 4 was replaced with 0.2 μL of DCE.
The DCE concentration was measured using a GC-8610 (manufactured by JEOL) and a PID detector.
The measurement results are shown by long dashed lines in FIG. However, the long broken line in FIG. 10 is the DCE elution amount, and the short broken line is the CE elution amount by-produced by the decomposition of DCE.
From FIG. 10, the DCE elution amount was less than the standard value in 7 days by the copper-containing iron powder, and the purification was achieved. Since CE increased to 3 days, it is considered that the byproduct of DCE decomposition was produced. However, CE was subsequently degraded and reached below the standard value on day 7, indicating that clean-up was achieved.
[実施例６]
実施例４のＣＥ標準１％ガス４．５ｍＬをＴＣＥ０．２μＬに置き換えた以外は、実施例４と同様の試験を行った。
尚、ＴＣＥ濃度はＧＣ−８６１０（ＪＥＯＬ製）、ＰＩＤ検出器にて測定した。
測定結果を図１１に実線で示す。但し、図１１中の実線はＴＣＥ溶出量、長破線はＴＣＥの分解により副生したＤＣＥ溶出量、短点線はＤＣＥの分解により副生したＣＥ溶出量である。
図１１より、ＴＣＥ溶出量は銅含有鉄粉により２８日で基準値０．０３ｍｇ／Ｌ未満になり、浄化が達成されたことが判明した。ＤＣＥは全日で検出されなかったことから、銅含有鉄粉ではＴＣＥからＤＣＥの副生はない、または検出限界値未満と微量であることが考えられた。ＣＥもＤＣＥと同様に全日で検出されなかった。
以上のことから、実施例３にて説明した純水の場合と同様、銅含有鉄粉を用いることで、ＴＣＥは、ＤＣＥおよびＣＥを副生させない、またはこれらの発生量を検出限界値より少ない微量に抑制されながら分解、浄化されたと考えられる。
[Example 6]
The same test as in Example 4 was conducted, except that 4.5 mL of the CE standard 1% gas of Example 4 was replaced with 0.2 μL of TCE.
The TCE concentration was measured with a GC-8610 (manufactured by JEOL) and a PID detector.
The measurement results are shown by solid lines in FIG. However, the solid line in FIG. 11 is the TCE elution amount, the long dashed line is the DCE elution amount by-produced by the decomposition of TCE, and the short dotted line is the CE elution amount by-produced by the decomposition of DCE.
From FIG. 11, it was found that the TCE elution amount was less than the reference value of 0.03 mg / L in 28 days by the copper-containing iron powder, and the purification was achieved. Since DCE was not detected on all days, it was considered that copper-containing iron powder had no by-products from TCE to DCE or was a trace amount below the detection limit. CE was not detected all day as well as DCE.
From the above, as in the case of the pure water described in Example 3, by using the copper-containing iron powder, TCE does not by-produce DCE and CE, or the amount of generation thereof is smaller than the detection limit value. It is thought that it was decomposed and purified while being suppressed to a small amount.
[実施例７]
銅含有鉄粉が、土壌中のＰＣＥ、および副生するＴＣＥ、ＤＣＥ、ＣＥを浄化可能であることを、実施例７にて確認した。
実施例７に係る試験の操作方法を、図１２を参照しながら説明する。
２０ｍｌバイアル瓶に、土壌１０ｇと、鉄粉として銅含有鉄粉（ＤＯＷＡ ＩＰクリエイション（株）製、Ｅ−４０１）１質量％とを投入して混合し、土壌中に鉄粉を分散させた。なお、使用した土壌は実施例４と同様で、砂質土壌、含水率２０質量％、ｐＨ６．５であった。
当該バイアル瓶をＮ２ガスでパージ後，テフロンシール付きシリコン栓およびアルミキャップで密栓した。そして、ＰＣＥ１．０μＬをシリンジで注入した。
当該バイアル瓶を常温で保管し、保管開始から０日目、１日目、４日目、７日目毎に、ヘッドスペース中のＰＣＥ濃度を測定した。
ＰＣＥ濃度測定には、ＧＣ−８６１０（ＪＥＯＬ製）を用い、ＰＩＤ検出器にてガス濃度を測定した。
ヘッドスペースガスと土壌中とに同量でＰＣＥが存在すると仮定し、溶出量換算して濃度を算出した。
測定結果を図１３のグラフに示す。但し、図１３中において二重線はＰＣＥ溶出量、実線はＰＣＥの分解により副生したＴＣＥ溶出量、長破線はＴＣＥの分解により副生したＤＣＥ溶出量、短破線はＤＣＥの分解により副生したＣＥ溶出量を示す。
図１３より、ＰＣＥは銅含有鉄粉により分解され、７日目には基準値未満となり、浄化が達成したたことが判明した。一方、ＴＣＥ、ＤＣＥおよびＣＥは検出されず、これらは副生されない、または検出限界値より少ない微量の発生量に抑制されながら分解、浄化されたと考えられる。
[Example 7]
It was confirmed in Example 7 that the copper-containing iron powder can purify PCE in the soil and TCE, DCE, and CE by-produced.
A test operation method according to Example 7 will be described with reference to FIG.
In a 20 ml vial, 10 g of soil and 1% by mass of copper-containing iron powder (E-401 manufactured by Dowa IP Creation Co., Ltd.) as iron powder were added and mixed to disperse iron powder in the soil. The soil used was the same as in Example 4; it was sandy soil, had a moisture content of 20% by mass, and had a pH of 6.5.
The vial was purged with N 2 gas, and then sealed with a Teflon-sealed silicon plug and an aluminum cap. Then, 1.0 μL of PCE was injected by a syringe.
The vial was stored at normal temperature, and the PCE concentration in the head space was measured every 0, 1, 4, and 7 days after the start of storage.
For the measurement of PCE concentration, gas concentration was measured with a PID detector using GC-8610 (manufactured by JEOL).
Assuming that PCE is present in the same amount in the head space gas and in the soil, the concentration was calculated by converting it into the elution amount.
The measurement results are shown in the graph of FIG. However, in FIG. 13, the double line is the PCE elution amount, the solid line is the TCE elution amount by-produced by PCE decomposition, the long dashed line is the DCE elution amount by-produced by TCE decomposition, and the short dashed line is by-product by DCE decomposition. Shows the eluted CE amount.
From FIG. 13, it was found that PCE was decomposed by the copper-containing iron powder and was below the reference value on the seventh day, and purification was achieved. On the other hand, TCE, DCE and CE were not detected, and it is considered that they were decomposed and purified while being suppressed to a small amount of generation not by-produced or smaller than the detection limit value.
Claims (11)
前記土壌中および／または地下水中へ、銅含有鉄粉を分散させて鉄粉分散層を敷設し、前記鉄粉分散層において前記クロロエチレンを分解することを特徴とするクロロエチレンの分解処理方法。 A method for decomposing chloroethylene in a soil contaminated with chloroethylene and having a water content of 5% by mass or more and / or in groundwater contaminated with chloroethylene,
A copper-containing iron powder is dispersed in the soil and / or underground water to lay an iron powder dispersion layer, and the chloroethylene is decomposed in the iron powder dispersion layer.
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| WO1997004868A1 (en) * | 1995-08-02 | 1997-02-13 | Monsanto Company | Dehalogenation of halogenated hydrocarbons in aqueous compositions |
| JP2000005740A (en) * | 1998-06-26 | 2000-01-11 | Dowa Mining Co Ltd | Cleaning method of soil and underground water contaminated with organic chlorine compound |
| WO2000029127A2 (en) * | 1998-11-18 | 2000-05-25 | Union Carbide Chemicals & Plastics Technology Corporation | Methods for the spray application of coatings using subcritical compressed fluids to reduce viscosity and enhance atomization |
| WO2007001309A2 (en) * | 2004-06-30 | 2007-01-04 | Auburn University | Preparation and applications of stabilized metal nanoparticles for dechlorination of chlorinated hydrocarbons in soils, sediments and groundwater |
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