JP4076510B2 - Environmental purification method - Google Patents

Environmental purification method Download PDF

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JP4076510B2
JP4076510B2 JP2004028104A JP2004028104A JP4076510B2 JP 4076510 B2 JP4076510 B2 JP 4076510B2 JP 2004028104 A JP2004028104 A JP 2004028104A JP 2004028104 A JP2004028104 A JP 2004028104A JP 4076510 B2 JP4076510 B2 JP 4076510B2
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gypsum
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JP2004255376A (en
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忠義 中村
敏 今村
直也 伊藤
謙一 佐々木
恭正 平井
薫 桜井
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石原産業株式会社
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本発明は水、土壌等に含まれる重金属イオンの吸着能に優れた環境浄化材及びそれを用いた環境浄化方法に関する。   The present invention relates to an environmental purification material having an excellent ability to adsorb heavy metal ions contained in water, soil, and the like, and an environmental purification method using the same.

クロム、ヒ素、セレン、カドミウム、水銀、鉛等の重金属は、種々の工業分野で使用されているが、微量でも毒性が強く、重金属による水質、土壌等の環境汚染が深刻な社会問題となっている。重金属で汚染された水の浄化方法としては、重金属をアルカリで中和し水酸化物として沈殿させ固液分離する水酸化物沈殿法、被処理水に第二鉄塩を添加して中和し、生成した水酸化鉄に重金属の水酸化物を吸着させ、固液分離する共沈法、被処理水に第一鉄塩を添加し中和・酸化して、重金属を鉄との複合酸化物として安定化させた後、磁力等により固液分離するフェライト法が知られている(非特許文献1参照)。また、重金属で汚染された土壌の処理は、例えば、汚染土壌を除去した後、セメント等で固化したり、汚染土壌のまわりをセメント等の遮蔽材で囲っている。   Heavy metals such as chromium, arsenic, selenium, cadmium, mercury and lead are used in various industrial fields, but they are highly toxic even in trace amounts, and environmental pollution such as water quality and soil caused by heavy metals is a serious social problem. Yes. Methods for purifying water contaminated with heavy metals include hydroxide precipitation, in which heavy metals are neutralized with alkali, precipitated as hydroxide, and separated into solid and liquid, and neutralized by adding ferric salt to the water to be treated. Co-precipitation method in which heavy metal hydroxide is adsorbed on the generated iron hydroxide and separated into solid and liquid, ferrous salt is added to the treated water, neutralized and oxidized, and heavy metal is mixed with iron After being stabilized, a ferrite method is known in which solid-liquid separation is performed by magnetic force or the like (see Non-Patent Document 1). The soil contaminated with heavy metals is treated by, for example, removing the contaminated soil and then solidifying it with cement or surrounding the contaminated soil with a shielding material such as cement.

しかし、水酸化物沈殿法は、多量のアルカリを必要とするばかりでなく、重金属の種類よって水酸化物が生成するpHが異なるので、重金属の種類が特定されない場合や数種の重金属により複合汚染されている場合には不向きであり、更に固液分離した水酸化物のスラッジから重金属が再溶出し易いという問題もある。また、共沈法は、吸着能力が不十分であり、フェライト法は、未反応の第一鉄塩により処理水が着色する場合がある。土壌処理においては、固化法は処分場の確保が必要であり、遮蔽法では、汚染土壌の再利用ができない。   However, the hydroxide precipitation method not only requires a large amount of alkali, but also the pH generated by the hydroxide differs depending on the type of heavy metal, so if the type of heavy metal is not specified or it is complex contamination with several heavy metals However, there is also a problem that heavy metals are easily re-eluted from the sludge of the hydroxide separated into solid and liquid. Further, the coprecipitation method has insufficient adsorption capacity, and the ferrite method may color the treated water with unreacted ferrous salt. In soil treatment, the solidification method requires securing a disposal site, and the shielding method cannot reuse contaminated soil.

本発明者らは、これらの問題点を解消すべく鋭意研究を重ねた結果、特定の比表面積を有する鉄酸化物は重金属の吸着能に優れ、しかも一旦吸着した重金属は再溶出し難いことを見出し、本発明を完成した。   As a result of intensive studies to solve these problems, the present inventors have found that iron oxides having a specific specific surface area are excellent in heavy metal adsorption ability, and that once adsorbed heavy metals are difficult to re-elute. The headline and the present invention were completed.

即ち、本発明は、比表面積が少なくとも100m/gである鉄酸化物を含むことを特徴とする環境浄化材である。 That is, this invention is an environmental purification material characterized by including the iron oxide whose specific surface area is at least 100 m < 2 > / g.

本発明は、重金属の吸着能に優れ、しかも一旦吸着した重金属は再溶出し難い。更に石膏を含む本発明の環境浄化材は、重金属で汚染され、しかも水分を多量に含み軟弱な土壌の浄化と土質改良に有用である。   The present invention is excellent in the ability to adsorb heavy metals, and the heavy metals once adsorbed are hardly re-eluting. Furthermore, the environmental purification material of the present invention containing gypsum is useful for purification and soil quality improvement of soft soil contaminated with heavy metals and containing a large amount of moisture.

本発明は環境浄化材であって、比表面積が少なくとも100m/gである鉄酸化物を含むことを特徴とする。本発明の環境浄化材は、重金属の吸着能力に優れ、しかも一旦吸着した重金属はほとんど再溶出しないので、長期にわたって重金属を安定化できる。これは、本発明で用いる鉄酸化物の比表面積が前記範囲のように大きく、物理的吸着、化学的吸着のいずれにも有利に働くためではないかと推測される。比表面積が100m/gより小さくなると吸着力は低くなるばかりでなく、一旦吸着した重金属が再溶出しやすくなる。本発明における比表面積は、BET法により測定したものであり、より好ましい比表面積の範囲は150〜300m/gである。本発明の環境浄化材には、この鉄酸化物が30重量%以上、好ましくは40重量%以上、更に好ましくは80重量%以上含まれていれば、所望の環境浄化能力が得られる。 This invention is an environmental purification material, Comprising: The iron oxide whose specific surface area is at least 100 m < 2 > / g is characterized by the above-mentioned. The environmental purification material of the present invention is excellent in heavy metal adsorption capacity, and the heavy metal once adsorbed hardly re-elutes, so that the heavy metal can be stabilized over a long period of time. This is presumed to be because the specific surface area of the iron oxide used in the present invention is as large as the above-mentioned range and works favorably for both physical adsorption and chemical adsorption. When the specific surface area is smaller than 100 m 2 / g, not only the adsorptive power is lowered but also the heavy metal once adsorbed is easily re-eluted. The specific surface area in this invention is measured by BET method, and the range of a more preferable specific surface area is 150-300 m < 2 > / g. If the environmental purification material of the present invention contains 30% by weight or more, preferably 40% by weight or more, and more preferably 80% by weight or more, the desired environmental purification ability can be obtained.

本発明における鉄酸化物とは、通常の酸化第一鉄(FeO)、酸化第二鉄(Fe)、四三酸化鉄(Fe)等の酸化鉄の他、鉄の水和酸化物を包含するもので、それらの単独でも混合物でも良く、鉄の水酸化物等の非晶質のものが含まれていてもよい。環境浄化材の性状は、粉体状、粒状、ペレット状、ウエットケーキ状等いずれでもよく、あるいは水等の分散媒に懸濁させスラリー状として用いてもよく、特に制限は無い。 The iron oxide in the present invention is iron oxide such as normal ferrous oxide (FeO), ferric oxide (Fe 2 O 3 ), triiron tetroxide (Fe 3 O 4 ), etc. They include hydrated oxides, and may be used alone or as a mixture thereof, or may be amorphous such as iron hydroxide. The nature of the environmental purification material may be any of powder, granules, pellets, wet cake, etc., or may be suspended in a dispersion medium such as water and used as a slurry, and is not particularly limited.

本発明の環境浄化材には、更にマンガン酸化物が含まれていると、重金属の吸着不溶化能力が高くなるので好ましい。マンガン酸化物は鉄酸化物との混合物として環境浄化材に含まれていてもよいが、鉄との複合酸化物として鉄酸化物中に含まれているのが特に好ましい。マンガン含有量は、Mn/Fe比で表して1〜20重量%の範囲が好ましく、より好ましくは5〜15重量%の範囲である。マンガン酸化物以外にも、本発明の効果を高める目的で、石膏等の固化材、活性炭、ゼオライト、キレート樹脂等の吸着材や、スラリー状で用いる場合、分散剤、凝集剤等が含まれていてもよい。   When the environmental purification material of the present invention further contains manganese oxide, it is preferable because the ability to adsorb and insolubilize heavy metals is increased. Manganese oxide may be contained in the environmental purification material as a mixture with iron oxide, but it is particularly preferred that it be contained in the iron oxide as a composite oxide with iron. The manganese content is preferably in the range of 1 to 20% by weight, more preferably in the range of 5 to 15% by weight, expressed as the Mn / Fe ratio. In addition to manganese oxide, for the purpose of enhancing the effect of the present invention, it includes a solidifying material such as gypsum, an adsorbing material such as activated carbon, zeolite, and chelate resin, and a dispersant, a flocculant and the like when used in a slurry state. May be.

特に、本発明の環境浄化材に石膏が含まれていると、重金属で汚染され、しかも水を多量に含む土壌に用いた場合、重金属の不溶化と土壌の固化とを同時に行えるので、建設工事、掘削工事、浚渫工事等によって発生した汚泥や軟弱土を、経済的に短期間で処理できる。石膏は中性であるので、被処理土壌は広範囲に再利用でき、しかも、土壌の植生を改良する効果も有する。本発明で用いる石膏は、二水石膏(CaSO・2HO)、半水石膏(CaSO・0.5HO)、無水石膏(CaSO)、またはそれらから選ばれる2種以上の混合物のいずれでもよい。半水石膏、無水石膏またはそれらの混合物は焼石膏とも呼ばれ、吸水性が高く、固化速度が速いので、焼石膏を用いるのが好ましい。石膏には、硫酸法酸化チタンの製造工程、鉄鋼材料の酸洗浄工程等の副産物や、リン酸石膏、脱硫石膏等の副生石膏、合成石膏、再生石膏等の化学石膏、及び、天然石膏等が、焼石膏にはこれら加熱焼成したものを用いることができる。 In particular, when gypsum is contained in the environmental purification material of the present invention, when used in soil contaminated with heavy metals and containing a large amount of water, insolubilization of heavy metals and solidification of the soil can be performed at the same time. The sludge and soft soil generated by excavation work and dredging work can be treated economically in a short period of time. Since gypsum is neutral, the treated soil can be reused extensively, and it also has the effect of improving soil vegetation. The gypsum used in the present invention is dihydrate gypsum (CaSO 4 · 2H 2 O), hemihydrate gypsum (CaSO 4 · 0.5H 2 O), anhydrous gypsum (CaSO 4 ), or a mixture of two or more thereof. Either of these may be used. Hemihydrate gypsum, anhydrous gypsum, or a mixture thereof is also called calcined gypsum, and it is preferable to use calcined gypsum because of its high water absorption and high solidification rate. Gypsum includes by-products such as sulfuric acid method titanium oxide manufacturing process, acid washing process of steel materials, by-product gypsum such as phosphate gypsum and desulfurized gypsum, synthetic gypsum, chemical gypsum such as recycled gypsum, and natural gypsum, etc. As the calcined gypsum, those heated and fired can be used.

石膏の含有量は、適用する土質、土壌の含水率等により適宜設定するが、通常は、鉄酸化物に対し重量比(CaSO:FeO)で0.5:1〜2:1の範囲が好ましく、0.7:1〜1.5:1の範囲が更に好ましい。浄化後の土壌を埋立、盛土等に再利用したり輸送する際に、成形性や付着性を改善する目的で、有機高分子、ベントナイト等の増粘剤を加えることもできる。有機高分子としては、例えば、ポリアクリル酸ソーダ、アクリル酸−アクリル酸エステル共重合体、アクリル酸ソーダ−アクリルアミド共重合体、カルボキシメチルセルロースソーダ塩、デンプン−アクリル酸−アクリル酸ソーダ共重合体、酢酸ビニル−マレイン酸ソーダ共重合体等のアニオン系のもの、ポリアクリルアミド、アルキルセルロース、ポリエチレンオキサイド等の非イオン系のもの等が挙げられる。 The content of gypsum is appropriately set depending on the soil to be applied, the moisture content of the soil, etc., but is usually 0.5: 1 to 2: 1 in weight ratio (CaSO 4 : Fe 2 O 3 ) to iron oxide. The range of 0.7: 1 to 1.5: 1 is more preferable. Thickeners such as organic polymers and bentonite can also be added for the purpose of improving moldability and adhesion when the purified soil is reused or transported to landfill, embankment or the like. Examples of the organic polymer include polyacrylic acid soda, acrylic acid-acrylic acid ester copolymer, sodium acrylate-acrylamide copolymer, carboxymethylcellulose soda salt, starch-acrylic acid-sodium acrylate copolymer, acetic acid. Anionic compounds such as vinyl-maleic acid soda copolymer and nonionic compounds such as polyacrylamide, alkyl cellulose, polyethylene oxide, and the like can be mentioned.

本発明の環境浄化材に含まれる鉄酸化物としては、第一鉄塩溶液を30〜70℃の範囲の温度下で且つpHが6〜9の範囲で中和・酸化して得られるものを用いると、更に重金属の吸着不溶化力が高くなり好ましい。この方法で得られた鉄酸化物は結晶性が低いので、表面の化学的活性が大きく、特に化学的吸着に有利であるためではないかと推測される。   The iron oxide contained in the environmental purification material of the present invention is obtained by neutralizing and oxidizing a ferrous salt solution at a temperature in the range of 30 to 70 ° C. and a pH in the range of 6 to 9. When used, it is preferable because the adsorption and insolubility of heavy metals is further increased. Since the iron oxide obtained by this method has low crystallinity, it is presumed that the chemical activity of the surface is large and it is particularly advantageous for chemical adsorption.

また、本発明の環境浄化材に含まれる鉄とマンガンの複合酸化物としては、第一鉄塩溶液に予め硫酸マンガン、塩化マンガン等のマンガン化合物を添加しておき、30〜70℃の範囲の温度下で且つpHが6〜9の範囲で中和・酸化して得ることができる。反応温度の好ましい範囲は40〜60℃であり、反応時の好ましいpHの範囲は7〜9である。   Moreover, as a complex oxide of iron and manganese contained in the environmental purification material of the present invention, a manganese compound such as manganese sulfate or manganese chloride is added in advance to the ferrous salt solution, and the temperature is in the range of 30 to 70 ° C. It can be obtained by neutralization and oxidation at a temperature and in the range of pH 6-9. A preferable range of the reaction temperature is 40 to 60 ° C., and a preferable pH range during the reaction is 7 to 9.

第一鉄塩としては硫酸第一鉄、塩化第一鉄等を用いることができる。特に、硫酸法酸化チタンの製造工程から発生する副生物は、廃硫酸と呼ばれ、硫酸第一鉄を主成分とし、しかも所望量の硫酸マンガンを含む溶液であるので、低コストであるばかりでなく、特にマンガン化合物を添加する必要が無いので、第一鉄塩とマンガン塩とを含む溶液として有利である。   As the ferrous salt, ferrous sulfate, ferrous chloride and the like can be used. In particular, the by-product generated from the production process of sulfuric acid method titanium oxide is called waste sulfuric acid, and it is a solution containing ferrous sulfate as a main component and containing a desired amount of manganese sulfate. In particular, since it is not necessary to add a manganese compound, it is advantageous as a solution containing a ferrous salt and a manganese salt.

また、中和剤としては、水酸化ナトリウム、水酸化カリウム等のアルカリ金属の水酸化物、水酸化カルシウム等のアルカリ土類金属の水酸化物、炭酸ナトリウム等のアルカリ金属の炭酸塩、炭酸カルシウム等のアルカリ土類金属の炭酸塩、アンモニウムガス、アンモニア水、炭酸アンモニウム等のアンモニウム化合物等の公知の塩基性化合物が挙げられる。酸化剤としては、空気、酸素、オゾン等の酸化性ガスや、過酸化水素等の酸化性化合物を用いることができ、特に、空気を溶液中を吹き込む方法は、経済的で取り扱い易く、工業的に有利である。反応温度、中和剤の種類および反応pH等の中和条件、並びに酸化剤の種類、量および酸化方法等の酸化条件を適宜、選択することにより、所望の比表面積並びにMn/Fe比を有する環境浄化材を得ることができる。   The neutralizing agent includes alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide, alkali metal carbonates such as sodium carbonate, calcium carbonate Known basic compounds such as alkaline earth metal carbonates such as ammonium gas, ammonium gas, ammonium water, and ammonium compounds such as ammonium carbonate. As the oxidizing agent, an oxidizing gas such as air, oxygen or ozone, or an oxidizing compound such as hydrogen peroxide can be used. In particular, the method of blowing air into the solution is economical, easy to handle, and industrial. Is advantageous. By appropriately selecting neutralization conditions such as reaction temperature, type of neutralizing agent and reaction pH, and oxidizing conditions such as type, amount and oxidizing method of oxidizing agent, it has a desired specific surface area and Mn / Fe ratio. Environmental purification material can be obtained.

石膏を含む環境浄化材を得るには、前記鉄酸化物と石膏とを混合してもよい。しかし、第一鉄塩を含む硫酸を、好ましくは硫酸法酸化チタンの製造工程や鉄鋼材料の酸洗浄工程から発生する廃硫酸を、更に好ましくは硫酸法酸化チタンの製造工程から発生する廃硫酸を、中和剤として水酸化カルシウム、炭酸カルシウム等の塩基性カルシウム化合物を用いて中和・酸化すると、前記鉄酸化物と二水石膏とを含む環境浄化材が得られ、更に、これを加熱焼成すると、前記鉄酸化物と焼石膏とを含む環境浄化材が得られる。この方法は、低コストであるので好ましい。中和・酸化は、30〜70℃の範囲の温度下で且つpHが6〜9の範囲で行うと、前記鉄酸化物が得られ易いので好ましい。反応温度の好ましい範囲は40〜60℃であり、反応時の好ましいpHの範囲は7〜9である。加熱焼成温度は95〜250℃の範囲が好ましく、100〜200℃の範囲が更に好ましい。   In order to obtain an environmental purification material containing gypsum, the iron oxide and gypsum may be mixed. However, the sulfuric acid containing ferrous salt is preferably waste sulfuric acid generated from the sulfuric acid process titanium oxide production process and the acid washing process of the steel material, more preferably waste sulfuric acid generated from the sulfuric acid process titanium oxide production process. When neutralized and oxidized using a basic calcium compound such as calcium hydroxide or calcium carbonate as a neutralizing agent, an environmental purification material containing the iron oxide and dihydrate gypsum is obtained. Then, the environmental purification material containing the said iron oxide and calcined gypsum is obtained. This method is preferable because of its low cost. The neutralization / oxidation is preferably performed at a temperature in the range of 30 to 70 ° C. and a pH in the range of 6 to 9, since the iron oxide is easily obtained. A preferable range of the reaction temperature is 40 to 60 ° C., and a preferable pH range during the reaction is 7 to 9. The heating and firing temperature is preferably in the range of 95 to 250 ° C, and more preferably in the range of 100 to 200 ° C.

本発明で処理対象となる有害物質の種類に特に制限は無く、クロム、ヒ素、セレン、カドミウム、水銀、鉛、ニッケル、スズ、亜鉛、銅、アンチモン等の重金属や、リン等が挙げられる。   There is no restriction | limiting in particular in the kind of hazardous | toxic substance processed by this invention, Heavy metals, such as chromium, arsenic, selenium, cadmium, mercury, lead, nickel, tin, zinc, copper, antimony, phosphorus, etc. are mentioned.

次の本発明は環境浄化方法であって、前記環境浄化材に水または土壌に含まれる重金属を吸着させることを特徴とする。水または土壌に含まれる重金属を吸着させるには、水処理や土壌処理で用いられている公知の方法を用いることができる。例えば、水処理では、本発明の環境浄化材を重金属を含む水に投入し、重金属を吸着不溶化させた後、環境浄化材を濾別しても良く、あるいは処理塔に充填したり、フィルターに担持させて用いることもできる。地下水の処理では、例えば、土壌中に本発明の環境浄化材を含む層を形成し、この層を地下水が透過する際に、地下水に含まれる重金属を吸着させることもできる。土壌処理では、重金属を含む土壌に直接投入する所謂原位置浄化法に有用であり、本発明では重金属を長期間安定して不溶化できるので、重金属を吸着不溶化させた後の環境浄化材は、特に回収する必要が無く、低コストで土壌を浄化できる。土壌に投入する方法には特に制限は無く、土壌を掘り起こし本発明の環境浄化材と混合した後埋め戻す、スラリー状にした本発明の環境浄化材を土壌に注入する等、土壌の性状、地形等に応じて適宜選択できる。本発明の環境浄化材を水中のリン除去に用いるのであれば、水のpHを中性から酸性の領域に、特に酸性領域に調整すると、リンの吸着能が向上するので好ましい。   The following present invention is an environmental purification method, characterized in that heavy metals contained in water or soil are adsorbed on the environmental purification material. In order to adsorb heavy metals contained in water or soil, a known method used in water treatment or soil treatment can be used. For example, in water treatment, the environmental purification material of the present invention may be poured into water containing heavy metal, and after heavy metal is adsorbed and insolubilized, the environmental purification material may be filtered off, or may be filled in a treatment tower or supported by a filter. Can also be used. In the treatment of groundwater, for example, a layer containing the environmental purification material of the present invention is formed in the soil, and when the groundwater permeates through this layer, heavy metals contained in the groundwater can be adsorbed. In soil treatment, it is useful for the so-called in-situ purification method that is directly put into the soil containing heavy metal.In the present invention, the heavy metal can be stably insolubilized for a long period of time. There is no need to collect and the soil can be purified at low cost. There is no particular limitation on the method of putting into the soil, the soil properties, topography, such as digging up the soil, mixing with the environmental purification material of the present invention and backfilling, injecting the slurry of the environmental purification material of the present invention into the soil, etc. It can be appropriately selected depending on the like. If the environmental purification material of the present invention is used for removing phosphorus in water, it is preferable to adjust the pH of water from a neutral to an acidic region, particularly an acidic region, because the phosphorus adsorption capacity is improved.

以下に本発明の実施例を示すが、本発明はこれらに限定されるものではない。   Examples of the present invention are shown below, but the present invention is not limited thereto.

実施例1
硫酸第一鉄溶液(Feとして6.7g/リットル)7リットルを45℃に昇温し、pHが8.5となるように20%苛性ソーダを添加しながら、溶液中に空気を吹き込み、鉄の酸化率が100%となるまで酸化した後、濾過、洗浄し、75℃で20時間乾燥して本発明の環境浄化材を得た。(試料A)
Example 1
While heating 7 liters of ferrous sulfate solution (6.7 g / liter as Fe) to 45 ° C. and adding 20% sodium hydroxide so that the pH is 8.5, air was blown into the solution, After oxidation until the oxidation rate reached 100%, filtration, washing and drying at 75 ° C. for 20 hours yielded the environmental purification material of the present invention. (Sample A)

実施例2
実施例1において、硫酸第一鉄溶液に替えて硫酸法酸化チタンの製造工程から発生した廃硫酸(硫酸第一鉄をFeとして6.7g/リットル、硫酸マンガンをMnとして0.7g/リットル含む)を用いた以外は同様にして、マンガン酸化物をMn/Feで9.5重量%含む本発明の環境浄化材を得た。(試料B)
Example 2
In Example 1, waste sulfuric acid generated from the production process of sulfuric acid method titanium oxide instead of ferrous sulfate solution (containing 6.7 g / liter of ferrous sulfate as Fe and 0.7 g / liter of manganese sulfate as Mn) The environmental purification material of the present invention containing manganese oxide in an amount of 9.5% by weight in terms of Mn / Fe was obtained in the same manner except that was used. (Sample B)

実施例3
実施例2で用いた廃硫酸7リットルを60℃に昇温し、pHが6.3となるように20%苛性ソーダを添加しながら、溶液中に空気を吹き込み、鉄の酸化率が100%となるまで酸化した後、濾過、洗浄して、マンガン酸化物をMn/Feで2.4重量%含む本発明の環境浄化材を得た。(試料C)
Example 3
7 liters of waste sulfuric acid used in Example 2 was heated to 60 ° C., and 20% caustic soda was added so that the pH was 6.3, while air was blown into the solution, and the oxidation rate of iron was 100%. After being oxidized until it was filtered, it was filtered and washed to obtain an environmental purification material of the present invention containing 2.4% by weight of manganese oxide in Mn / Fe. (Sample C)

比較例1
硫酸第一鉄溶液(Feとして60g/リットル)7リットルを42℃に昇温し、20%苛性ソーダでpHを7.3に調製した後、溶液中に空気を吹き込み、pHが4以下になった時点で反応を終了し、濾過、洗浄して比較試料の環境浄化材を得た。(試料D)
Comparative Example 1
After heating 7 liters of ferrous sulfate solution (60 g / liter as Fe) to 42 ° C. and adjusting the pH to 7.3 with 20% caustic soda, air was blown into the solution, and the pH became 4 or less. At the time point, the reaction was terminated, filtered and washed to obtain an environmental purification material as a comparative sample. (Sample D)

評価1:比表面積の測定
実施例1〜3及び比較例1で得られた試料A〜Dをの比表面積を比表面積測定装置(モノソーブMS−16型、ユアサアイオニクス製)を用いてBET法により測定した。その結果を、表1に示す。
Evaluation 1: Measurement of specific surface area The specific surface area of samples A to D obtained in Examples 1 to 3 and Comparative Example 1 was measured using a specific surface area measuring device (Monosorb MS-16, manufactured by Yuasa Ionics) with the BET method. It was measured by. The results are shown in Table 1.

評価2:重金属の吸着能力の測定
クロム、ヒ素、セレン、カドミウム、水銀及び鉛を含むpH4の試験液(I)に、実施例1〜3及び比較例1で得られた試料A〜Dを酸化鉄濃度が1g/リットルになるように添加し、2時間攪拌後、試料を遠心分離し、さらに0.45μmのメンブランフィルターを用いて濾過した。試験液及び各瀘液に含まれる上記重金属の濃度を、原子吸光分析により測定した。また、重金属の濃度の異なる試験液(II)に、試料A〜Dを酸化鉄濃度が50g/リットルになるように添加したこと以外は同様にして、重金属の濃度を測定した。結果を表2に示す。本発明の環境浄化材は、重金属の吸着力、特に高濃度での吸着力が優れていることが判る。
Evaluation 2: Measurement of heavy metal adsorption capacity Samples A to D obtained in Examples 1 to 3 and Comparative Example 1 were oxidized in a pH 4 test solution (I) containing chromium, arsenic, selenium, cadmium, mercury and lead. The mixture was added so that the iron concentration became 1 g / liter and stirred for 2 hours, and then the sample was centrifuged, and further filtered using a 0.45 μm membrane filter. The concentration of the heavy metal contained in the test solution and each of the filtrates was measured by atomic absorption analysis. Further, the concentration of heavy metal was measured in the same manner except that Samples A to D were added to the test solution (II) having different heavy metal concentrations so that the iron oxide concentration was 50 g / liter. The results are shown in Table 2. It can be seen that the environmental purification material of the present invention is excellent in the adsorption power of heavy metals, particularly at a high concentration.

評価3:重金属の不溶化能力の測定
評価2の試験液(II)を処理後、遠心分離した残渣を分取、風乾し、乾燥品50gを500ccの超純水と混合し、6時間振とう(4cm、200回/分)を行った。30分静置後、遠心分離し、0.45μmのメンブランフィルターを用いて濾過した。瀘液に含まれる前記重金属の濃度を、原子吸光分析により測定した。その結果を、表3に示す。本発明の環境浄化材は、吸着した重金属をほとんど再溶出しないことが判る。
Evaluation 3: Measurement of insolubilization ability of heavy metal After treating the test solution (II) of Evaluation 2, the centrifuged residue was collected and air-dried, and 50 g of the dried product was mixed with 500 cc of ultrapure water and shaken for 6 hours ( 4 cm, 200 times / min). After leaving still for 30 minutes, it centrifuged and filtered using a 0.45 micrometer membrane filter. The concentration of the heavy metal contained in the filtrate was measured by atomic absorption analysis. The results are shown in Table 3. It can be seen that the environmental purification material of the present invention hardly re-elutes the adsorbed heavy metal.

評価3:リンの吸着能力の測定
リン酸水素二ナトリウム水和物(NaHPO・12HO)を用いてリン濃度が10mg/リットルになるように試験液(III)を調整した。希硫酸を用いてpHを7.1に調整した試験液(III)200ミリリットルに実施例2及び比較例1で得られた試料B、Dを0.2g加え、2時間攪拌した後、試験液のリン濃度を原子吸光分析により測定した。また、試験液のpHを再度測定した。その後、硫酸を用いてpHを約3に調整して更に1時間攪拌した後、同様に試験液のリン濃度とpHを測定した。結果を表4に示す。本発明の環境浄化材が水中のリンの除去にも用いることができ、特に酸性領域でリンの吸着力が優れていることが判る。
Evaluation 3: Measurement of Adsorption Capacity of Phosphorus Test liquid (III) was adjusted using phosphoric acid disodium hydrogen phosphate hydrate (Na 2 HPO 4 · 12H 2 O) so that the phosphorus concentration was 10 mg / liter. After adding 0.2 g of Samples B and D obtained in Example 2 and Comparative Example 1 to 200 ml of test solution (III) adjusted to pH 7.1 with dilute sulfuric acid, the test solution was stirred for 2 hours. The phosphorus concentration of was measured by atomic absorption analysis. Further, the pH of the test solution was measured again. Then, after adjusting pH to about 3 using sulfuric acid and stirring for another hour, the phosphorus concentration and pH of the test solution were measured in the same manner. The results are shown in Table 4. It can be seen that the environmental purification material of the present invention can also be used for removing phosphorus in water, and has an excellent phosphorus adsorption power particularly in an acidic region.

実施例4
20%苛性ソーダに替えて15%水酸化カルシウムを用いた以外は、実施例2と同様にして得た生成物を濾過、洗浄後、120℃の温度で1時間加熱焼成し、マンガン酸化物をMn/Feで9重量%含む鉄酸化物と焼石膏とを重量比(CaSO:FeO)で1:1の割合で含む本発明の環境浄化材を得た。(試料E)
Example 4
The product obtained in the same manner as in Example 2 except that 15% calcium hydroxide was used in place of 20% caustic soda was filtered, washed, and then heated and fired at a temperature of 120 ° C. for 1 hour to convert manganese oxide into Mn. An environmental purification material of the present invention containing iron oxide and calcined gypsum containing 9 wt% of / Fe at a weight ratio (CaSO 4 : Fe 2 O 3 ) of 1: 1 was obtained. (Sample E)

評価4:試料に含まれる鉄酸化物の比表面積の測定
実施例4で得られた試料E1gを500ccの水に投入し、攪拌して石膏を溶解し、濾過、洗浄して鉄酸化物を分離後、75℃の温度で20時間乾燥した後、鉄酸化物の比表面積を評価1と同様にして測定した。その結果、試料Eに含まれる鉄酸化物の比表面積は、210m/gであった。
Evaluation 4: Measurement of specific surface area of iron oxide contained in sample The sample E1 g obtained in Example 4 was put into 500 cc of water, stirred to dissolve gypsum, filtered and washed to separate the iron oxide. Then, after drying for 20 hours at a temperature of 75 ° C., the specific surface area of the iron oxide was measured in the same manner as in Evaluation 1. As a result, the specific surface area of the iron oxide contained in Sample E was 210 m 2 / g.

評価4:重金属の不溶化能力及び固化能力の測定
砒素を含む汚染土壌(含水比23%)100重量部に対し、実施例4で得られた試料E10重量部を混合し、24時間養生させた。養生後の処理土を分取、風乾し、乾燥品50gを500ccの超純水と混合し、6時間振とう(4cm、200回/分)を行った。30分静置後、遠心分離し、0.45μmのメンブランフィルターを用いて濾過した。瀘液に含まれる砒素の濃度を、原子吸光分析により測定した。また、処理土をもう一部分取し成形した後、コーン指数を測定した。コーン指数が大きい程、固化強度が高い。試料を加えない汚染土壌のみで、同様にして砒素の濃度、コーン指数を測定した。これを比較例2とする。評価結果を表5に示す。本発明の石膏を含む環境浄化材は重金属の不溶化能力が高く、しかも土壌の強度を向上させることが判る。
Evaluation 4: Measurement of insolubilization ability and solidification ability of heavy metal 10 parts by weight of sample E obtained in Example 4 was mixed with 100 parts by weight of contaminated soil containing arsenic (water content ratio: 23%) and cured for 24 hours. The treated soil after curing was separated and air-dried, and 50 g of the dried product was mixed with 500 cc of ultrapure water and shaken for 6 hours (4 cm, 200 times / min). After leaving still for 30 minutes, it centrifuged and filtered using a 0.45 micrometer membrane filter. The concentration of arsenic contained in the filtrate was measured by atomic absorption analysis. Further, after a part of the treated soil was taken and molded, the cone index was measured. The larger the corn index, the higher the solidification strength. Arsenic concentration and corn index were measured in the same manner using only contaminated soil to which no sample was added. This is referred to as Comparative Example 2. The evaluation results are shown in Table 5. It can be seen that the environmental purification material containing gypsum of the present invention has a high insolubilizing ability of heavy metals and improves the strength of the soil.

本発明の環境浄化材は、重金属で汚染された水質や土壌の浄化に有用である。更に石膏を含む本発明の環境浄化材は、重金属で汚染され、しかも水分を多量に含み軟弱な土壌の浄化と土質改良に有用である。
The environmental purification material of the present invention is useful for purification of water quality and soil contaminated with heavy metals. Furthermore, the environmental purification material of the present invention containing gypsum is useful for purification and soil quality improvement of soft soil contaminated with heavy metals and containing a large amount of moisture.

Claims (1)

  1. 硫酸第一鉄と硫酸マンガンとを含む溶液を30〜70℃の範囲の温度下で且つpHが6〜9の範囲で塩基性カルシウム化合物を用いて中和・酸化することで、比表面積が少なくとも100m/gである鉄とマンガンの複合酸化物および石膏を含有する重金属吸着材を得る工程、並びに前記工程で得られた重金属吸着材に水または土壌に含まれる重金属を吸着させる工程とを含むことを特徴とする環境浄化方法。 By neutralization and oxidation using a solution basic calcium compound and a range of pH 6 to 9 at temperatures ranging from 30 to 70 ° C. The containing ferrous sulfate manganese sulfate, the specific surface area A step of obtaining a heavy metal adsorbent containing a composite oxide of iron and manganese and gypsum that is at least 100 m 2 / g, and a step of adsorbing heavy metal contained in water or soil to the heavy metal adsorbent obtained in the step environmental purification method, characterized in that it comprises.
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JP2006116477A (en) * 2004-10-22 2006-05-11 Miura Co Ltd Arsenic removing agent and arsenic removing method
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