Method for remedying heavy metal-contaminated soil by combining chemical reduction and chemical leaching

A technology of polluted soil and chemical leaching is applied in the field of combining chemical reduction and chemical leaching to remove heavy metals adsorbed by soil iron and manganese oxides. The effect of improving leaching efficiency, reducing ecological risk and improving removal rate

Active Publication Date: 2014-03-05
ZHONGKE DINGSHI ENVIRONMENTAL ENG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the relatively large proportion in the soil and not easy to be desorbed by the eluent, the efficiency of the traditional eluent is often not high
The iron-manganese bonded state accounts for a large proportion of the entire form, and has strong activity. It is easily converted into an effective state after leaching and absorbed by plants. If the leaching efficiency of this form is not high, there will be serious ecological risks.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The soil around a mining area in Linxiang, Hunan was collected, and its basic physical and chemical properties were measured: arsenic: 46.7mg / kg, cadmium: 1.34mg / kg, lead: 383mg / kg, pH=6.1, and the collected soil was air-dried at room temperature. Air-dried and ground, passed through a 100-mesh sieve, and fully stirred evenly;

[0022] (1) Weigh 10g of soil into a 250ml Erlenmeyer flask, add 100ml of 0.5mol / L Na 2 EDTA aqueous solution, and adjust the pH to 4.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0023] (2) Add 100ml of 0.5mol / L Na 2 EDTA aqueous solution, and adjust the pH to 4.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0024] (3) Add 100ml of deionized water to the re-centrifuged soil, shake at room temperature at...

Embodiment 2

[0026] The soil around a mining area in Linxiang, Hunan was collected, and its basic physical and chemical properties were measured: arsenic: 46.7mg / kg, cadmium: 1.34mg / kg, lead: 383mg / kg, pH=6.1, and the collected soil was air-dried at room temperature. Air-dried and ground, passed through a 100-mesh sieve, and fully stirred evenly;

[0027] (1) Weigh 10g of soil into a 250ml Erlenmeyer flask, add 100ml of 0.5mol / L Na 2 EDTA aqueous solution, and adjust the pH to 4.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0028] (2) Add 100ml of 0.5mol / L NH to the centrifuged soil 2 OH·HCl aqueous solution, and adjust the pH to 1.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0029] (3) Add 100ml of deionized water to the re-centrifuged soil, sh...

Embodiment 3

[0031] The soil around a mining area in Linxiang, Hunan was collected, and its basic physical and chemical properties were measured: arsenic: 46.7mg / kg, cadmium: 1.34mg / kg, lead: 383mg / kg, pH=6.1, and the collected soil was air-dried at room temperature. After air-drying, grind and pass through a 100-mesh sieve, fully stir evenly;

[0032] (1) Weigh 10g of soil into a 250ml Erlenmeyer flask, add 100ml of 0.5mol / L NH 2OH·HCl aqueous solution, and adjust the pH to 1.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0033] (2) Add 100ml of 0.5mol / L Na to the centrifuged soil 2 EDTA aqueous solution, and adjust the pH to 4.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0034] (3) Add 100ml of deionized water to the re-centrifuged soil, shake ...

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Abstract

The invention relates to a method for remedying heavy metal-contaminated soil by combining chemical reduction and chemical leaching, and aims to provide a method for remediation by virtue of combination of chemical reduction and chemical leaching. The method is used for eluting iron and manganese oxides to improve an effect of removing heavy metals from soil by using a leaching agent. The method comprises the following steps of performing leaching by using a reducing agent aqueous solution, namely performing vibratory washing on the contaminated soil by using the reducing agent aqueous solution, and filtering washing liquid after centrifugation; and performing leaching by using a Na2EDTA (Ethylene Diamine Tetraacetic Acid) aqueous solution, namely adding the Na2EDTA aqueous solution into the contaminated soil leached by the reducing agent aqueous solution for vibratory washing, and filtering washing liquid after centrifugation.

Description

technical field [0001] The invention relates to the field of soil heavy metal pollution treatment and restoration, in particular to a method combining chemical reduction and chemical leaching for eluting heavy metals adsorbed by soil iron and manganese oxides. Background technique [0002] In recent years, leaching technology has become one of the most important means in the treatment of heavy metal-contaminated soil. The leaching technology not only realizes the separation of heavy metals from the soil, but also has the advantages of quick results and no restrictions on climate and other conditions, and has gradually been widely used. . In the Superfund Program implemented in the United States in the 1990s, large-scale leaching restoration projects have begun. The key to leaching technology lies in the choice of leaching agent. There are many kinds of leaching agents: chelating agent, inorganic leaching agent, surfactant, etc. In a large number of tests and projects at hom...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/08
Inventor 杨勇殷晓东王海东徐峰黄海
Owner ZHONGKE DINGSHI ENVIRONMENTAL ENG CO LTD
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