Mercury contaminated soil in-situ restoration method

An in-situ remediation and mercury-contaminated technology, applied in the field of in-situ remediation of mercury-contaminated soil, can solve problems such as difficult implementation, unreasonable application of mercury-containing fertilizers and pesticides, and large land area, so as to reduce purification costs, cheap raw materials, The effect of simple preparation method

Active Publication Date: 2013-01-16
PEKING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

2) Man-made pollution, mainly from sewage irrigation, discharge from mercury smelters and mercury preparation factories (chlor-alkali industry, electrical appliances, instruments); unreasonable use of mercury-containing fertilizers and pesticides in agricultural farming, etc.
Because the current action distance is too small, and the actual polluted land area is too large, this technology is difficult to implement in engineering, and despite its high operating costs, it is unaffordable

Method used

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  • Mercury contaminated soil in-situ restoration method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 1) Extracting agent raw material 1 (10 kg sodium iodide, 10 kg sodium sulfate, 10 kg ammonium nitrate and 10 kg ammonium thiosulfate, sodium iodide: sodium sulfate: ammonium nitrate: ammonium thiosulfate mass ratio 1:1 :1:1,) into the stirring tank 2, dissolved in 360 kg of water, and configured as an extractant 3 with a mass concentration of 10%.

[0029] 2) In the extraction kettle 4, 80 kg of mercury-contaminated soil 5 and 400 kg of extractant 3 are fully stirred and mixed, the mass ratio of mercury-contaminated soil:extractant 3 is 1:5, the stirring time is 2 hours, and the centrifuge 6 is used for centrifugation . Clean soil 7 is obtained after separation.

[0030] 3) Transfer the 330 cubic meters of extract 8 produced after centrifugation into the precipitation reactor 9, add 1 kg of sodium sulfide precipitant 10, that is, add 0.33 kg of sulfide per cubic meter of supernatant, stir well, and react for 20 minute. The centrifuge 11 is used for centrifugal separa...

Embodiment 2

[0032] 1) Extracting agent raw material 1 (10 kg ammonium iodide, 10 kg potassium sulfate, 10 kg sodium nitrate and 10 kg sodium thiosulfate, ammonium iodide: potassium sulfate: sodium nitrate: sodium thiosulfate mass ratio 1:1 :1:1,) into the stirring tank 2, dissolved in 460 kg of water, and configured as an extraction agent 3 with a mass concentration of 8%.

[0033] 2) In the extraction kettle 4, 125 kg of mercury-contaminated soil 5 and 500 kg of extractant 3 are fully stirred and mixed, the mass ratio of mercury-contaminated soil:extractant 3 is 1:4, the stirring time is 2 hours, and the centrifuge 6 is used for centrifugation . Clean soil 7 is obtained after separation.

[0034] 3) Transfer the 420 cubic meters of extract 8 produced after centrifugation into the precipitation reactor 9, add 0.84 kg of potassium sulfide precipitant 10, that is, add 0.2 kg of sulfide per cubic meter of supernatant, stir well, and react for 20 minute. The centrifuge 11 is used for centr...

Embodiment 3

[0036] 1) Extraction agent raw material 1 (3.75 kg potassium iodide, 3.75 kg ammonium sulfate, 3.75 kg potassium nitrate and 3.75 kg potassium thiosulfate, potassium iodide: ammonium sulfate: potassium nitrate: potassium thiosulfate mass ratio 1:1:1:1 ,) into the stirring tank 2, dissolved in 285 kg of water, and configured as an extractant 3 with a mass concentration of 5%. Contaminated soil: extractant mass ratio = 1:3, stirring time 2 hours, centrifuged by centrifuge 6. Clean soil 7 is obtained after separation.

[0037] 3) Transfer the 280 cubic meters of extract 8 produced after centrifugation into the precipitation reactor 9, add 0.84 kg of calcium sulfide precipitant 10, that is, add 0.3 kg of sulfide per cubic meter of supernatant, stir well, and react for 20 minute. The centrifuge 11 is used for centrifugal separation to recover the mercury sulfide 12 and realize the regeneration of the extraction agent at the same time. The regenerated extractant 13 is reused in t...

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Abstract

The invention discloses a mercury contaminated soil in-situ restoration method. The method includes: preparation of extracting agent, namely dissolving water-soluble iodized salt, sulfate, nitrate and thiosulfate into water to prepare the extracting agent for restoration of mercury contaminated soil; and purification of mercury contaminated soil and regeneration of the extracting agent, namely subjecting the mercury contaminated soil and the extracting agent to mixing, stirring and centrifugal separation, wherein the centrifuged soil is clean soil; extracting 90% of mercury absorbable and usable for plants into supernatant, adding precipitating agent to recover mercuric sulfide and realize regeneration of the extracting agent, and reusing the regenerated extracting agent for the soil. Details are shown in the specification. The mercury contaminated soil in-situ restoration method has the advantages that mercury absorbable and usable for plants in soil is separated by extracting, and the purification efficiency is up to 90%; and materials of the extracting agent are low in cost and easy to obtain, the extracting agent preparation method is simple, feasible, recyclable and reusable, and thereby mercury contaminated soil purification cost is greatly reduced.

Description

technical field [0001] The invention relates to a treatment method for polluted soil, in particular to an in-situ restoration method for mercury polluted soil. Background technique [0002] Since the first case of methylmercury poisoning was discovered in Kumamoto Prefecture, Japan in the 1950s, scholars in different research fields have paid great attention to mercury pollution. There are three main sources of mercury in soil: 1) Natural release of mercury, including volcanic and geothermal activities, transpiration of soil, natural water bodies and plant surfaces, forest fires and rock weathering. Mercury pollution caused by such natural factors usually accounts for 1 / 4 of the total mercury emissions. 2) Man-made pollution, mainly from sewage irrigation, emissions from mercury smelters and mercury preparation plants (chlor-alkali industry, electrical appliances, instruments); agricultural farming Unreasonable application of mercury-containing fertilizers and pesticides. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/02
Inventor 刘阳生向月娇
Owner PEKING UNIV
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