Hexavalent chromium contaminated soil in-situ remediation method

A technology for in-situ remediation of contaminated soil, applied in the field of in-situ remediation of hexavalent chromium-contaminated soil, which can solve the problems of hexavalent chromium leaching, pollution, and polluted surrounding soil, and achieve stable trivalent chromium, simple operation method, and cheap raw materials Effect

Active Publication Date: 2015-08-19
PEKING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

According to reports, in the past 30 years of reform and opening up, my country has accumulated 6 million tons of chromium slag due to metallurgical and chemical production, and the annual output has increased by 200,000 to 300,000 tons. Many factories lack good chromium slag treatment facilities and pile up everywhere, resulting in Hexavalent chromium leaching from chromium-containing waste and further polluting the surrounding soil
2) Sewage irrigation and sludge use, sewage irrigation leads to excessive chromium concentration in rice fields in many sewage irrigation areas
3) Irrational applic

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The object of the embodiment is the soil polluted by the chromium slag leachate of a certain chemical plant. The chromium content in the soil is 5628.9 mg / kg of hexavalent chromium. Utilize the method of the present invention to repair hexavalent chromium polluted soil main steps are as follows:

[0022] 1) 10 kilograms of sodium thiosulfate are dissolved in 90 kilograms of water to be configured as a reducing agent with a mass concentration of 10%.

[0023] 2) dissolving 10 kg of disodium hydrogen phosphate in 90 kg of water to prepare a stabilizer with a mass concentration of 10%.

[0024] 3) 100 kilograms of hexavalent chromium-contaminated soil and 50 kilograms of reducing agent are fully stirred and mixed, and the stirring time is 2 hours, and the obtained soil is dried;

[0025] 4) 100 kg of reduced and dried soil and 50 kg of stabilizer were fully stirred and mixed for 2 hours, and the obtained soil was dried.

[0026] After the above steps are completed, the ...

Embodiment 2

[0028] The object targeted by the embodiment is certain soil polluted by hexavalent chromium. The chromium content in the soil is 526.3 mg / kg of hexavalent chromium. Utilize the method of the present invention to repair hexavalent chromium polluted soil main steps are as follows:

[0029] 1) Dissolving 1 kg of sodium sulfide in 90 kg of water to prepare a reducing agent with a mass concentration of 0.1%.

[0030] 2) Dissolving 1 kilogram of phosphoric acid in 99 kilograms of water is configured as a stabilizer with a mass concentration of 0.1%.

[0031] 3) 100 kilograms of hexavalent chromium-contaminated soil and 200 kilograms of reducing agent are fully stirred and mixed, and the stirring time is 2 hours, and the obtained soil is dried;

[0032] 4) 100 kg of reduced and dried soil and 300 kg of stabilizer were fully stirred and mixed for 2 hours, and the obtained soil was dried.

[0033] After the above steps are completed, the concentration of hexavalent chromium in the ...

Embodiment 3

[0035] The object targeted by the embodiment is certain hexavalent chromium-contaminated soil. The chromium content in the soil is 2572.4 mg / kg of hexavalent chromium. Utilize the method of the present invention to repair hexavalent chromium polluted soil main steps are as follows:

[0036] 1) 5 kilograms of sodium thiosulfate and 5 kilograms of ferrous sulfite are dissolved in 90 kilograms of water to prepare a reducing agent with a mass concentration of 10%.

[0037] 2) Dissolving 5 kilograms of sodium phosphate and 5 kilograms of disodium hydrogen phosphate in 190 kilograms of water to prepare a stabilizer with a mass concentration of 5%.

[0038] 3) 100 kilograms of hexavalent chromium-contaminated soil and 50 kilograms of reducing agent are fully stirred and mixed, and the stirring time is 2 hours, and the obtained soil is dried;

[0039] 4) 100 kg of reduced and dried soil and 50 kg of stabilizer were fully stirred and mixed for 2 hours, and the obtained soil was dried...

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Abstract

The invention discloses a hexavalent chromium contaminated soil in-situ remediation method. The method comprises the following steps: dissolving a water-soluble sulfur-containing reagent into water, preparing 0.1-10 percent of a reducing agent, mixing chromium contaminated soil and the reducing agent in a reactor according to a mass ratio of the soil to the reducing agent being 3:1-1:5, stirring for 0.5-2 hours, and drying. Then, a stabilizer is added for treatment, so that the soil meets the environmental risk control requirement. The hexavalent chromium which is high in toxicity and easy to migrate and can be absorbed and utilized by plants in the soil is completely reduced and immobilized into trivalent chromium which is low in toxicity and difficult to migrate and can be utilized by plants, and bounce is difficultly caused. The in-situ remediation of the heavy metal hexavalent chromium contaminated soil is realized.

Description

technical field [0001] The invention relates to an in-situ remediation technology for hexavalent chromium-contaminated soil. Specifically, by configuring a water-soluble sulfur-containing reagent as a reducing agent and a water-soluble phosphorus-containing reagent as a stabilizer, the highly toxic soil that can be The hexavalent chromium absorbed and utilized by plants is reduced and fixed, and the in-situ remediation of hexavalent chromium-contaminated soil is realized. Background technique [0002] my country's soil is seriously polluted by heavy metals. The "National Soil Pollution Survey Bulletin" shows that the national chromium pollution rate is 1.1%, which is one of the eight major polluting heavy metals. There are many sources of chromium in soil, among which the most serious hazards mainly contain three aspects: 1) Random dumping of industrial waste and municipal waste. According to reports, in the past 30 years of reform and opening up, my country has accumulate...

Claims

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Application Information

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IPC IPC(8): B09C1/08
Inventor 刘阳生李芸邑
Owner PEKING UNIV
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