Compound chemical leaching method for efficient remediation of heavy metal contaminated soil

A contaminated soil and chemical leaching technology, applied in the field of soil remediation, can solve the problems of large-scale promotion and application of large treatment costs, difficulty in obtaining large-scale promotion, and easy to produce secondary pollution, etc., to achieve rapid and efficient leaching repair, Wide application value and market promotion prospect, fast removal effect by leaching

Inactive Publication Date: 2017-06-13
东莞中科土壤科技开发有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Inorganic leaching agent is a method of eluting heavy metals from soil through the ion exchange of water, inorganic acid, inorganic salt solution, etc. This method is low in cost, but has the disadvantages of low leaching efficiency and large water consumption; chelating agent is Using EDTA, citric acid, etc. to desorb the heavy metal ions attached to the surface of soil particles through chelation has the advantages of fast and efficient, but the high cost of large investment makes this method difficult to be widely used; surfactants The purpose of pollutant elution is achieved by changing the surface properties of the soil or ion exchange, etc., but there are disadvantages such as high regeneration cost and easy to produce secondary pollution; the compound chemical leaching method is a hot spot in the field of soil remediation at present, and its principle is Through the synergistic effect of various leaching agents, the method for efficiently eluting heavy metal ions in contaminated soil, such as the patent application of publication number CN105478467A, uses EDTA and calcium oxide as raw materials to prepare EDTA calcium salt composite leaching soil. The method for heavy metals Cu, Zn, Pb, and Cd, the patent application of publication number CN104492806A uses Aspergillus niger liquid and citric acid as raw materials to prepare eluent to restore chromium-contaminated soil. Although this type of method has the characteristics of high efficiency and wide application , but there are still disadvantages such as high cost, complicated operation, easy to produce secondary pollution, etc.
[0004] In short, the current soil leaching and restoration technologies are restricted by their own shortcomings, and it is difficult to obtain large-scale promotion. Therefore, it is very necessary to develop new soil remediation and leaching methods.

Method used

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  • Compound chemical leaching method for efficient remediation of heavy metal contaminated soil

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] 1) First, weigh 0.9g of citric acid, 0.3g of glacial acetic acid, 4.1g of ferric chloride and 6.1g of ferric nitrate and add them to 100ml of deionized water, stir and dissolve, and obtain a standby compound eluent for repairing heavy metal-contaminated soil;

[0028] 2) Grinding the soil polluted by heavy metals through a 10-mesh sieve to remove coarse debris in the soil;

[0029] 3) Weigh 2g of the contaminated soil obtained in step 2) into a 100ml centrifuge tube, add 20ml of the compound eluent obtained in step 1) at a solid-to-liquid ratio of 1:10, and place it in a shaker at room temperature for 180r min -1 Shake for 90min, and then use a centrifuge at 2500r·min -1 Centrifuge for 10 minutes to separate the mud and water.

[0030] 4) Filter the waste liquid after rinsing, and then regenerate it with iron-manganese double metal oxide modified porous adsorption material for 15 minutes.

[0031] 5) Other steps remain unchanged, and the soil leaching test is carried ...

Embodiment 2

[0033] 1) First weigh 1.3g of citric acid, 0.5g of glacial acetic acid, 5.4g of ferric chloride and 7.3g of ferric nitrate and add them to 100ml of deionized water, stir and dissolve to obtain a standby compound eluent for repairing heavy metal-contaminated soil;

[0034] 2) Grinding the soil polluted by heavy metals through a 10-mesh sieve to remove coarse debris in the soil;

[0035] 3) Weigh 2g of the contaminated soil obtained in step 2) into a 100ml centrifuge tube, add 30ml of the compound eluent obtained in step 1) at a solid-to-liquid ratio of 1:15, and place it in a shaker at room temperature for 180r min -1 Shake for 150min, then centrifuge at 2500r min -1 Centrifuge for 10 minutes to separate mud and water;

[0036] 4) The waste liquid after rinsing is regenerated through the recycled material.

Embodiment 3

[0038] 1) First weigh 1.7g of citric acid, 0.3g of glacial acetic acid, 6.8g of ferric chloride and 8.2g of ferric nitrate and add them to 100ml of deionized water, stir and dissolve to obtain a standby compound eluent for repairing heavy metal-contaminated soil;

[0039] 2) Grinding the soil polluted by heavy metals through a 10-mesh sieve to remove coarse debris in the soil;

[0040] 3) Weigh 2g of the contaminated soil obtained in step 2) and add it to a 100ml centrifuge tube, add 10ml of the compound eluent obtained in step 1) at a solid-to-liquid ratio of 1:5, and place it in a shaker at room temperature for 180r min -1 Shake for 120min, then centrifuge at 2500r min -1 Centrifuge for 10 minutes to separate mud and water;

[0041] 4) The waste liquid after rinsing is regenerated through the recycled material.

[0042] Table 2 shows the heavy metal content in the soil after the repair treatment of the present invention.

[0043] Table 2 Heavy metal content in soil after ...

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Abstract

The invention relates to the field of soil remediation, in particular to a compound chemical leaching method for efficient remediation of heavy metal contaminated soil. Natural organic acid and iron salt are used as main raw materials to prepare a compound leacheate, and the technical problems that an existing soil remediation eluent is high in cost and low in efficiency and can cause secondary pollution easily are solved. According to the compound chemical leaching method, the heavy metal contaminated soil is remediated, the heavy metal content in the soil can be reduced quickly, and a good remediation effect is achieved. Waste liquid generated after leaching is disposed through a regenerant, and the primary regeneration efficiency can reach 80% or over.

Description

technical field [0001] The invention relates to the field of soil remediation, in particular to a compound chemical leaching method for efficiently remediating heavy metal-contaminated soil. Background technique [0002] Soil pollution is one of the most serious environmental problems facing human society, and the remediation of contaminated soil has become a hot spot in the field of environmental remediation. Existing soil remediation technologies mainly include thermal desorption technology, electrodynamic remediation, biological remediation, solidification and stabilization remediation and soil leaching remediation. Among them, soil leaching remediation of heavy metal-contaminated soil is due to its rapid remediation, wide adaptability and thorough remediation. It has been widely studied and applied to actual restoration projects because of its characteristics, and has broad market space and development prospects. [0003] At present, the leaching agents for leaching and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/02B09C1/08
CPCB09C1/02B09C1/08
Inventor 肖定书李小飞郑煜基何辉
Owner 东莞中科土壤科技开发有限公司
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