Remediation method of heavy metal contaminated soil

A technology of polluted soil and remediation method, which is applied in the field of soil remediation and governance, can solve the problems of reduced utilization efficiency, secondary pollution, and high cost, and achieve the effects of preventing agglomeration, improving utilization efficiency, and improving dispersion

Active Publication Date: 2017-07-28
沃邦环保有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] At present, the commonly used chemical fixatives are divided into several categories such as natural minerals, organic matter, lime, and replacement metals. These chemical fixatives have the following problems: the fixation efficiency of natural mineral fixatives for heavy metals is low; When the fixative is used for the remediation of heavy metal-contaminated soil, there is secondary pollution; lime-based fixatives usually change the soil pH to make heavy metals form hydroxides and carbonates. After adding lime-based fixatives to the soil, it will cause After repairing, the soil is hardened and expanded, and the fixation effect of heavy metals in the soil by compounds such as hydroxides and carbonates formed after the hydration reaction is easily affected by external environmental conditions. After long-term weathering and acid rain erosion, the soil The heavy metals in it have the potential danger of being re-dissolved
However, the cost of submicron or nanometer iron is high, and it is easily oxidized by the surrounding medium (such as dissolved oxygen, water), resulting in a decrease in its utilization efficiency; in addition, the transfer of nanometer zero-valent iron in non-porous media is very slow, which further limits its use. Applications in Soil Remediation

Method used

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  • Remediation method of heavy metal contaminated soil

Examples

Experimental program
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Effect test

Embodiment 1

[0024] Preparation of Chemical Stabilizer for Heavy Metal Contaminated Soil Remediation

[0025] (1) Preparation of solid conditioner: uniformly mix fly ash, phosphogypsum and red mud according to a weight ratio of 48:27:22 to obtain a solid conditioner;

[0026] (2) Preparation of liquid stabilizer: under nitrogen atmosphere and mechanical stirring (rotating speed 400r / min), rhamnolipid solution (2g / L) and FeCl 3 After the solution (0.2mol / L) was fully mixed, it was added dropwise with FeCl 3 solution with an equal volume of NaHB 4 Solution (0.4mol / L) was reacted, and after the bubbles were no longer generated, the reaction was completed, and the rhamnolipid-coated zero-valent nano-iron suspension was obtained, which was sealed and stored at room temperature.

[0027] figure 1 The scanning electron microscope image of the rhamnolipid-coated zero-valent nano-iron suspension prepared for this example, it can be seen from the figure that the zero-valent nano-iron particles ar...

Embodiment 2

[0037] A method for repairing heavy metal contaminated soil, comprising the following steps:

[0038] S1: Use an excavator to dig out the 20cm-thick soil on the surface layer of heavy metal contaminated soil left over from a non-ferrous mining area in Xianghualing area, Linwu County, and crush and screen the excavated soil, and evenly distribute it on the anti-seepage layer;

[0039] S2: Add the solid conditioner prepared in step (1) of Example 1 into the excavated soil in step S1 and stir and mix, and the addition amount per kilogram of polluted soil is 20%wt;

[0040] S3: After 2 months, the liquid stabilizer prepared in step (2) was sprayed in the heavy metal-contaminated soil, and the addition amount per kilogram of contaminated soil was 20%wt. After 6 months of maintenance, most of the heavy metals Pb, Zn, Cu, Cd, and Hg in the original heavy metal-contaminated soil were reduced to low-priced immobilized heavy metals, indicating that this method has realized the in-situ r...

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Abstract

The invention discloses a remediation method of heavy metal contaminated soil. The method comprises the following steps: (1) excavating, breaking and screening the heavy metal contaminated soil; (2) conditioning the contaminated soil by using a solid conditioning agent; and (3) reducing heavy metals in the contaminated soil by using a liquid stabilizer. The remediation method of the heavy metal contaminated soil has the advantages of low cost, excellent effect, high efficiency and environment friendliness.

Description

technical field [0001] The invention relates to the technical field of soil remediation and treatment, in particular to a method for remediating heavy metal-contaminated soil. Background technique [0002] With the upgrading of my country's industrial structure and the adjustment of urban layout, a large number of polluting enterprises have been closed and relocated in many cities, resulting in the emergence of a large number of industrially polluted sites in cities, among which heavy metal contaminated soil is a common type of industrially polluted sites. Most of these polluted sites face changes in land use due to re-use. Due to the long-term, potential and irreversible harm of heavy metals to animals, plants and human bodies, corresponding restoration should be carried out before the contaminated soil is reused to ensure the site environment and the safety of residents. healthy. [0003] At present, the remediation of heavy metal-contaminated soil mainly includes physica...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/08B09C1/00
CPCB09C1/00B09C1/08
Inventor 刘军亮
Owner 沃邦环保有限公司
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