A method for efficiently repairing mercury-contaminated soil by leaching and a leaching agent

A mercury pollution and soil technology, applied in the restoration of polluted soil and other directions, can solve the problems of low leaching efficiency, low secondary pollution, and low mercury residue, and achieve enhanced leaching efficiency, good effect and synergistic effect. powerful effect

Active Publication Date: 2020-06-12
AEROSPACE KAITIAN ENVIRONMENTAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Another object of the present invention is to provide a method for remediating mercury-contaminated soil that can achieve efficient elution of various valence states of mercury in mercury-contaminated soil, with low residual mercury and low secondary pollution to the environment. The removal rate of mercury in the soil after remediation can reach 90%, which solves the problem of low leaching efficiency of general mercury-contaminated soil

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] The contaminated farmland soil around a mercury mine in Guizhou was taken, and the mercury content in the soil was 7.8 mg / kg. After the soil was naturally air-dried, it was ground and passed through a 20-mesh sieve for use. Configure oxidizing agent, eluent I and eluent II respectively, wherein oxidant is that 4% potassium persulfate solution is added in 5% HCl solution, the volume ratio is 1:10, and the concentration of citric acid in eluent I is 1moL / L, the concentration of potassium iodide is 0.1moL / L, the concentration of calcium chloride is 0.3moL / L, the mass percentage concentration of sodium sulfide in the eluent II is 5%, and the amount of sodium hydroxide added is 1.5% of the amount of sodium sulfide. Weigh 5g of the pretreated soil into a 100mL centrifuge tube, add deionized water to keep the soil moist, and then add the prepared oxidant potassium persulfate solution to control the potassium persulfate in the potassium persulfate solution and the mercury in the...

Embodiment 2

[0053] Get the same soil as in Example 1, and through the same air-drying, grinding and sieving process, configure oxidizing agent, eluent I and eluent II respectively, wherein the oxidizing agent is that 4% sodium persulfate solution is added to 5% In the HCl solution, the volume ratio is 1:10, and the eluent I is citric acid, sodium iodide and sodium chloride, wherein the concentration of citric acid is 1moL / L, the concentration of sodium iodide is 0.1moL / L, and the concentration of sodium chloride is 0.1moL / L. Concentration is 0.3moL / L, and eluent II is identical with embodiment 1. Take by weighing 5g of pretreated soil in a 100mL centrifuge tube, the next oxidation step is the same as in Example 1, and the mercury content in the soil measured after air-drying is 0.87mg / kg, which is higher than the value in Example 1 , but lower than the "Soil Environmental Quality Standard" (GB15618-1995) level 3 standard value (1.5mg / kg), the soil mercury removal rate is 88.85%.

Embodiment 3

[0055] Get the same soil as in Example 1, and through the same air-drying, grinding and sieving process, configure oxidizing agent, eluent I and eluent II respectively, wherein the oxidizing agent is that 4% potassium persulfate solution is added to 5% In the HCl solution, the volume ratio is 1:10, and the eluent I is tartaric acid, potassium iodide and potassium chloride, wherein the concentration of tartaric acid is 1moL / L, the concentration of potassium iodide is 0.1moL / L, and the concentration of potassium chloride is 0.3moL / L , Eluent II is the same as in Example 1. Take by weighing 5g of pretreated soil in a 100mL centrifuge tube, the next oxidation step is the same as in Example 1, and the mercury content in the soil measured after air-drying is 0.81 mg / kg, which is higher than the value in Example 1 , but lower than the "Soil Environmental Quality Standard" (GB15618-1995) level 3 standard value (1.5mg / kg), the soil mercury removal rate is 89.62%.

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Abstract

The invention discloses a method for efficient remediation of mercury-contaminated soil by leaching and a leaching agent. The leaching agent is composed of an oxidizing agent, a leaching solution I and a leaching solution II, wherein the oxidizing agent is a persulfate solution, a solute of the leaching solution I is composed of organic acid, iodized salt and chloride salt, and a solute of the leaching solution II is composed of sodium sulfide and sodium hydroxide. The method for leaching the mercury-contaminated soil by adopting the leaching agent comprises the steps that oxidation treatment is carried out on the mercury-contaminated soil, and then the mercury-contaminated soil is sequentially subjected to leaching by adopting the leaching solution I and the leaching solution II. The method has the advantages that efficient elution of mercury with various valence state in the mercury-contaminated soil can be realized, mercury residues are little, in addition, secondary pollution to the environment can be avoided, and the cost is low.

Description

technical field [0001] The invention relates to a mercury-contaminated soil remediation agent and method, in particular to a method for repairing mercury-contaminated soil by leaching using a special leaching agent, and belongs to the technical field of heavy metal soil treatment. Background technique [0002] In recent years, with the rapid development of industry and agriculture, a large amount of mercury has been released in the process of production and use, making the soil polluted by mercury more and more serious. The main sources of soil mercury pollution are atmospheric deposition, sewage irrigation, industrial pollution sources (coal-burning, chlor-alkali industry, battery factory, smelting, papermaking and other industries), agricultural pollution sources (use of pesticides and fertilizers), mercury-containing waste (thermometers, waste battery, etc.) mishandled, etc. Mercury and its compounds in the soil can enter the human body through the food chain, causing gr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B09C1/02B09C1/08
CPCB09C1/02B09C1/08
Inventor 邵乐史学峰韩凤刘晓月李昌武
Owner AEROSPACE KAITIAN ENVIRONMENTAL TECH CO LTD
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