DE4219420A1 - Metallic mercury removal from soil with organic chelating agent and oxidant - e.g. di:ethylene-tri:amine-penta:acetic acid and hydrogen peroxide for easy purificn. to legal limit - Google Patents

Metallic mercury removal from soil with organic chelating agent and oxidant - e.g. di:ethylene-tri:amine-penta:acetic acid and hydrogen peroxide for easy purificn. to legal limit

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Publication number
DE4219420A1
DE4219420A1 DE19924219420 DE4219420A DE4219420A1 DE 4219420 A1 DE4219420 A1 DE 4219420A1 DE 19924219420 DE19924219420 DE 19924219420 DE 4219420 A DE4219420 A DE 4219420A DE 4219420 A1 DE4219420 A1 DE 4219420A1
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DE
Germany
Prior art keywords
soil
ppm
hydrogen peroxide
pref
oxidant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
DE19924219420
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German (de)
Inventor
Paul Dr Klingelhoefer
Alfred Dr Ruland
Uwe Dr Gauglitz
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BASF SE
Original Assignee
BASF SE
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Filing date
Publication date
Application filed by BASF SE filed Critical BASF SE
Priority to DE19924219420 priority Critical patent/DE4219420A1/en
Publication of DE4219420A1 publication Critical patent/DE4219420A1/en
Withdrawn legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
    • A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
    • A62D3/38—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by oxidation; by combustion
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
    • A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
    • A62D3/33—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by chemical fixing the harmful substance, e.g. by chelation or complexation
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
    • A62D2101/40—Inorganic substances
    • A62D2101/43—Inorganic substances containing heavy metals, in the bonded or free state
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D2203/00—Aspects of processes for making harmful chemical substances harmless, or less harmful, by effecting chemical change in the substances
    • A62D2203/04—Combined processes involving two or more non-distinct steps covered by groups A62D3/10 - A62D3/40

Abstract

Removal of metallic Hg from soil is effected by treating the soil with organic chelating agent (I) in the presence of an oxidant (II). (I) has a Hg2+ complex formation constant of over 10 power 22 and pref. is diethylenetriaminepentaacetic acid (DTPA); and (II) is NaOCl, alkali peroxydisulphate or pref. H2O2. Treatment pref. is carried out with 3-8% (I) soln. and 0.1-1, pref. 0.3-0.8% H2O2 at pH under 9, pref. 5-8. ADVANTAGE - The Hg content of the soil can be reduced from values as high as e.g. 10000 ppm to 1-25 ppm, so that the legal limit can be attained easily. In an example, 100g samples of (A) loam contg. 105000 ppm Hg, (B-G) loam contg. 95 ppm Hg and (H) sandy soil contg. 80 ppm Hg (from a rstoration project), all homogenised by ball milling, placed in a column and covered with 1 kg aq. extn. soln. contg. (E) 1, rest 7% DTPA.Na5 and (F,G) 0.1, rest 0.6% H2O2, adjusted to pH (D) O, rest pH 6 with dil. HNO3. The flow rate was adjusted to 10-20 drops/min.. The Hg concn. was reduced to (A) 10, (B) 2.4, (C) 2.8, (D,E) 6, (F) 9, (G) 13, (H) 12 ppm.

Description

Die Erfindung betrifft ein Verfahren zur Entfernung von metallischem Quecksilber aus Böden durch Extraktion.The invention relates to a method for removing metallic mercury from soil by extraction.

Es sind schon verschiedene Verfahren zur Reinigung von mit metallischem Quecksilber belasteten Böden empfohlen worden. Beispielsweise sollen solche Böden in Öfen erhitzt werden, wobei das Quecksilber verdampft und in nachgeschalteten Kon­ densatoren gewonnen wird (Verfahren der Firma Umwelt-Tech­ nics-Nord GmbH, Norderstedt). Entsprechend den Angaben der DE-OS 38 12 986 ist es möglich, durch ein Extraktionsmittel, bestehend aus verdünnter Salpetersäure und Natriumchlorid die mit metallischem Quecksilber kontaminierten Böden (bei 50 bis 60°C) in einem Gegenstromextraktor zu reinigen. Die angegebenen Verfahren führen jedoch noch nicht zu zufrieden­ stellenden Ergebnissen. So tritt bei dem in der DE-OS be­ schriebenen Verfahren wegen der Pufferwirkung des Bodens ein hoher Verbrauch an Säure auf, wohingegen bei thermischen Verfahren große Energieeinträge notwendig sind und eine si­ chere Reinigung der Abgase sehr schwierig ist.There are various methods of cleaning with metallic mercury contaminated floors have been recommended. For example, such floors should be heated in ovens, the mercury evaporates and in downstream con capacitors is obtained (process from Umwelt-Tech nics-Nord GmbH, Norderstedt). According to the information from DE-OS 38 12 986 it is possible to use an extraction agent, consisting of dilute nitric acid and sodium chloride soils contaminated with metallic mercury (at 50 to 60 ° C) in a countercurrent extractor. The However, the specified procedures are not yet satisfactory results. So be at the in the DE-OS procedures because of the buffer effect of the soil high consumption of acid, whereas thermal Procedure large energy inputs are necessary and a si Exhaust gas cleaning is very difficult.

Das erfindungsgemäße Verfahren ist nun dadurch gekenn­ zeichnet, daß man mit metallischem Quecksilber verunreinigte Böden mit einem organischen Komplexbildner in Gegenwart eines Oxidationsmittels behandelt.The method according to the invention is now known records that one was contaminated with metallic mercury Soils with an organic complexing agent in the presence treated with an oxidizing agent.

Das erfindungsgemäße Verfahren wird zweckmäßigerweise so durchgeführt, daß man den kontaminierten Boden mit einer das Oxidationsmittel und den Komplexbildner enthaltenden wäß­ rigen Lösung behandelt. Die Behandlung kann z. B. in einer Säule durch Elution, im Rührkessel unter guter Durchmischung oder im Gegenstrom erfolgen. Vorzugsweise wird der konta­ minierte Boden als homogene Masse in einen offenen Behälter gegeben und mit dem Extraktionsmittel besprüht. Die ver­ sprühte Lösung wird gesammelt und im Kreislauf geführt. Ent­ sprechende Apparate und Einrichtungen sind aus dem Stand der Technik bekannt. The method according to the invention is expediently so performed that the contaminated soil with a Oxidizing agents and the complexing agent containing aq treated solution. The treatment can e.g. B. in one Column by elution, in a stirred tank with thorough mixing or in countercurrent. Preferably, the contact mined soil as a homogeneous mass in an open container given and sprayed with the extractant. The ver sprayed solution is collected and circulated. Ent speaking apparatus and devices are from the state of the Technology known.  

Die Extraktion des Quecksilbers erfolgt üblicherweise bei Umgebungstemperatur, es ist aber auch möglich, bei erhöhter oder erniedrigter Temperatur oder auch Unter- oder Überdruck zu arbeiten.The mercury is usually extracted at Ambient temperature, but it is also possible at elevated or reduced temperature or negative or positive pressure to work.

Als Oxidationsmittel können z. B. Alkalihypochlorite, Alkali­ peroxodisulfate und vorzugsweise Wasserstoffperoxid in Betracht. Das Oxidationsmittel H2O2 wird, bezogen auf die Extraktionslösung, zweckmäßigerweise in Konzentrationen von 0,1 bis 1%, vorzugsweise 0,3 bis 0,8 Gew.-% verwendet; zweckmäßige Konzentrationen anderer Oxidationsmittel lassen sich durch Vorversuche leicht ermitteln.As an oxidizing agent such. B. alkali hypochlorites, alkali peroxodisulfate and preferably hydrogen peroxide. The oxidizing agent H 2 O 2 , based on the extraction solution, is expediently used in concentrations of 0.1 to 1%, preferably 0.3 to 0.8% by weight; Appropriate concentrations of other oxidizing agents can easily be determined by preliminary tests.

Geeignete pH-Werte für das erfindungsgemäße Verfahren liegen für H2O2 in der Nähe des Neutralpunktes, insbesondere zwischen 5 und 8.Suitable H 2 O 2 pH values for the process according to the invention are in the vicinity of the neutral point, in particular between 5 and 8.

Die Komplexbildner werden ebenfalls bezogen auf die wäßrige Lösung üblicherweise in Konzentrationen zwischen 1 und 15, vorzugsweise 3 und 8 Gew.-% verwendet.The complexing agents are also based on the aqueous Solution usually in concentrations between 1 and 15, preferably 3 and 8 wt .-% used.

Geeignet sind insbesondere Verbindungen mit einer Komplex­ bildungskonstanten gegenüber Hg2+ von < 1022 (bei 25°C und einer Ionenstärke von 0,1).Compounds with a complex formation constant with respect to Hg 2+ of <10 22 (at 25 ° C. and an ionic strength of 0.1) are particularly suitable.

Besonders bevorzugt ist Diethylentriaminpentaessigsäure (DTPA) in Form der Alkalisalze, wobei die Verbindung ganz oder teilweise neutralisiert sein kann. Natriumsalze sind bevorzugt und die Neutralisation ergibt sich aus dem ge­ wünschten pH-Wert.Diethylenetriaminepentaacetic acid is particularly preferred (DTPA) in the form of the alkali salts, the compound being whole or partially neutralized. Are sodium salts preferred and the neutralization results from the ge wanted pH.

Das erfindungsgemäß zu entfernende Quecksilber liegt in der Regel adsorbiert vor und kann daher im Gegensatz zu in Tröpfchenform anwesendem Quecksilber nicht durch mechanische Verfahren, wie Zentrifugieren, abgetrennt werden.The mercury to be removed according to the invention is in the Rule adsorbs before and can therefore in contrast to in Mercury present in droplet form not by mechanical Methods such as centrifugation are separated.

Um die Benetzbarkeit von Böden zu erhöhen, kann es zweck­ mäßig sein, Netzmittel mitzuverwenden; solche Netzmittel sind beispielsweise Nekal®X trocken (Na-Salz einer Naphthalin-disulfonsäure). In order to increase the wettability of soils, it can be useful be moderate to use wetting agents; such wetting agents are, for example, Nekal®X dry (Na salt one Naphthalene disulfonic acid).  

Das extrahierte Quecksilber liegt in der Extraktionslösung als Hg2+ vor und kann nach an sich bekannten Methoden daraus isoliert werden, beispielsweise durch Fällung als Queck­ silbersulfid. Beim Arbeiten mit H2O2 als Oxidationsmittel wird dieses vorher zerstört.The extracted mercury is present in the extraction solution as Hg 2+ and can be isolated therefrom by methods known per se, for example by precipitation as mercury sulfide. When working with H 2 O 2 as an oxidizing agent, it is destroyed beforehand.

Das erfindungsgemäße Verfahren ermöglicht es, selbst Böden mit sehr hohen Quecksilbergehalten, z. B. solchen mit 10 000 ppm auf Konzentrationen von 1 bis 25 ppm abzu­ reichern. Es können somit in einfacher Weise die gesetzlich zugelassenen Grenzwerte erreicht werden.The method according to the invention enables even soils with very high mercury levels, e.g. B. such with 10,000 ppm down to concentrations of 1 to 25 ppm enrich. It can therefore be legally permitted limit values can be reached.

BeispieleExamples Allgemeine VersuchsbedingungenGeneral test conditions

Für die Versuche wurden folgende Böden verwendet:
Boden A: Lehmboden mit 10 500 ppm Quecksilber (durch Mahlen in der Kugelmühle homogen eingearbeitet)
Boden B: Lehmboden mit 95 ppm Quecksilber (durch Mahlen in der Kugelmühle homogen eingearbeitet)
Boden C: sandiger Boden mit 80 ppm Quecksilber aus einem Sanierungsprojekt (durch Mahlen in der Kugelmühle homogenisiert)The following soils were used for the tests:
Soil A: clay soil with 10 500 ppm mercury (homogeneously incorporated by milling in a ball mill)
Soil B: clay soil with 95 ppm mercury (homogeneously incorporated by milling in a ball mill)
Soil C: sandy soil with 80 ppm mercury from a renovation project (homogenized by milling in a ball mill)

VersuchsdurchführungTest execution

100 g des jeweiligen Bodens wurden in eine 2 Liter fassende Säule mit einer Watte- und einer Sandschicht gegeben. Es wurde mit 1 kg der Extraktionslösung, bestehend aus einer wäßrigen Lösung des Pentanatriumsalzes der Diethylentriamin­ pentaessigsäure und Wasserstoffperoxid überschichtet. Die Fließgeschwindigkeit wurde auf 10 bis 20 Tropfen/min einge­ stellt. Alle Versuche wurden bei Raumtemperatur durchge­ führt. Der pH-Wert wurde mit verdünnter Salpetersäure einge­ stellt. 100 g of the respective soil were put into a 2 liter Pillar with a layer of cotton and sand. It was with 1 kg of the extraction solution consisting of a aqueous solution of the pentasodium salt of diethylenetriamine pentaacetic acid and hydrogen peroxide overlaid. The Flow rate was set at 10 to 20 drops / min poses. All experiments were carried out at room temperature leads. The pH was adjusted with dilute nitric acid poses.  

Folgende Ergebnisse wurden erhalten:The following results were obtained:

Claims (7)

1. Verfahren zur Entfernung von metallischem Quecksilber aus Böden, dadurch gekennzeichnet, daß man die Böden mit einem organischen Komplexbildner in Gegenwart eines Oxidationsmittels behandelt.1. A process for removing metallic mercury from soils, characterized in that the soils are treated with an organic complexing agent in the presence of an oxidizing agent. 2. Verfahren gemäß Anspruch 1, dadurch gekennzeichnet, daß man als Komplexbildner Verbindungen mit einer Komplex­ bildungskonstanten gegenüber Hg2+ < 1022 und als Oxida­ tionsmittel Wasserstoffperoxid, Natriumhypochlorit oder Alkaliperoxidisulfate verwendet.2. The method according to claim 1, characterized in that one uses as complexing agent compounds with a complex formation constant against Hg 2+ <10 22 and as an oxidizing agent hydrogen peroxide, sodium hypochlorite or alkali peroxidisulfates. 3. Verfahren gemäß Anspruch 1, dadurch gekennzeichnet, daß man Wasserstoffperoxid verwendet.3. The method according to claim 1, characterized in that to use hydrogen peroxide. 4. Verfahren gemäß Anspruch 1, dadurch gekennzeichnet, daß man Wasserstoffperoxid in Konzentrationen von 0,1 bis 1%, vorzugsweise 0,3 bis 0,8%, verwendet.4. The method according to claim 1, characterized in that to hydrogen peroxide in concentrations of 0.1 to 1%, preferably 0.3 to 0.8%, is used. 5. Verfahren gemäß Anspruch 3, dadurch gekennzeichnet, daß man bei pH-Werten < 9, vorzugsweise zwischen 5 und 8, arbeitet.5. The method according to claim 3, characterized in that one at pH values <9, preferably between 5 and 8, is working. 6. Verfahren gemäß Anspruch 1, dadurch gekennzeichnet, daß man 1 bis 15, vorzugsweise 3 bis 8%ige Komplexbildner­ lösungen verwendet.6. The method according to claim 1, characterized in that 1 to 15, preferably 3 to 8% complexing agents solutions used. 7. Verfahren gemäß Anspruch 6, dadurch gekennzeichnet, daß man als Komplexbildner Diethylentriaminpentaessigsäure (DTPA) oder deren Salze verwendet.7. The method according to claim 6, characterized in that one as a complexing agent diethylenetriaminepentaacetic acid (DTPA) or their salts used.
DE19924219420 1992-06-13 1992-06-13 Metallic mercury removal from soil with organic chelating agent and oxidant - e.g. di:ethylene-tri:amine-penta:acetic acid and hydrogen peroxide for easy purificn. to legal limit Withdrawn DE4219420A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19924219420 DE4219420A1 (en) 1992-06-13 1992-06-13 Metallic mercury removal from soil with organic chelating agent and oxidant - e.g. di:ethylene-tri:amine-penta:acetic acid and hydrogen peroxide for easy purificn. to legal limit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19924219420 DE4219420A1 (en) 1992-06-13 1992-06-13 Metallic mercury removal from soil with organic chelating agent and oxidant - e.g. di:ethylene-tri:amine-penta:acetic acid and hydrogen peroxide for easy purificn. to legal limit

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DE4219420A1 true DE4219420A1 (en) 1993-12-16

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4317338A1 (en) * 1993-05-25 1994-12-01 Dyckerhoff & Widmann Ag Process for decontaminating polluted soils, sludges, ashes, sediments or the like
DE19717122A1 (en) * 1997-04-23 1998-10-29 Kali Umwelttechnik Sondershaus Mineral building material
DE102010017075A1 (en) 2010-05-25 2011-12-01 Sascha Schröder Method for decontamination of ground soil loaded with mercury and/or volatile carbon containing organic pollutants or oil, involves supplying exhaust stem to condenser where pollutant-specific separation takes place
US10138657B2 (en) 2013-01-16 2018-11-27 Kiekert Aktiengesellschaft Motor vehicle door lock

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4317338A1 (en) * 1993-05-25 1994-12-01 Dyckerhoff & Widmann Ag Process for decontaminating polluted soils, sludges, ashes, sediments or the like
DE19717122A1 (en) * 1997-04-23 1998-10-29 Kali Umwelttechnik Sondershaus Mineral building material
DE102010017075A1 (en) 2010-05-25 2011-12-01 Sascha Schröder Method for decontamination of ground soil loaded with mercury and/or volatile carbon containing organic pollutants or oil, involves supplying exhaust stem to condenser where pollutant-specific separation takes place
US10138657B2 (en) 2013-01-16 2018-11-27 Kiekert Aktiengesellschaft Motor vehicle door lock

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