Two-level remediation method of heavy metal contaminated soil

A technology for contaminated soil and heavy metals, applied in the field of contaminated soil treatment, can solve the problems of unsatisfactory restoration of contaminated soil, achieve the effect of reducing the number of residues and improving soil quality

Active Publication Date: 2014-07-02
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But the problem is that the adsorbed ions in this kind of adsorption phenomenon are easier to release, which is not ideal for the restoration of contaminated soil.

Method used

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  • Two-level remediation method of heavy metal contaminated soil
  • Two-level remediation method of heavy metal contaminated soil
  • Two-level remediation method of heavy metal contaminated soil

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] A method for secondary restoration of heavy metal contaminated soil, comprising the following steps:

[0030] (1) Break up a dry paddy field polluted by heavy metals, and break the soil at a depth of 0.5m on the surface to clods less than 2mm; irrigate until the accumulated water layer on the soil layer reaches a depth of 10cm; add light ceramsite-shaped improved The modified clay mineral adsorbent was mechanically stirred for 20 minutes and left to stand for 6 hours, and the adsorbent that had completed the adsorption was removed and the supernatant was discharged at the same time to complete the primary repair; the modified clay mineral adsorbent was Mongolian Lightweight ceramsite made of a mixture of destoned clay modified adsorbent, chitosan modified clay, bentonite modified clay, and phosphoric acid modified attapulgite, the pH value is 5, and the mixing ratio is 1:2 by volume: 1:1;

[0031] (2) Put the adsorbent that has completed adsorption taken out in step (1) ...

Embodiment 2

[0049] Remediation of contaminated soil in a suburb of the Pearl River Delta:

[0050] A method for secondary restoration of heavy metal contaminated soil, comprising the following steps:

[0051] (1) Break up a dry paddy field polluted by heavy metals, and break the soil at a depth of 0.55m on the surface to clods less than 2.5mm; irrigate until the accumulated water layer on the soil layer reaches a depth of 12.5cm; add light ceramsite The modified clay mineral adsorbent is mechanically stirred for 25 minutes, and left to stand for 7 hours, and the adsorbent that is floating on the water surface and completed the adsorption is taken out, and the supernatant is discharged at the same time to complete the primary repair; the modified clay mineral adsorbent Lightweight ceramsite made from a mixture of montmorillonite clay modified adsorbent, chitosan modified clay, bentonite modified clay and phosphoric acid modified attapulgite, the pH value is 6.5, and the mixing ratio is vol...

Embodiment 3

[0069] The experiment on a polluted land in the Pearl River Delta is as follows:

[0070] Remediation of contaminated soil in a suburb of the Pearl River Delta:

[0071] A method for secondary restoration of heavy metal contaminated soil, comprising the following steps:

[0072] (1) Break up a dry paddy field polluted by heavy metals, and break the soil at a depth of 0.6m on the surface to clods less than 3mm; irrigate until the water layer on the soil layer reaches a depth of 15cm; add light ceramsite modified The modified clay mineral adsorbent was mechanically stirred for 30 minutes and left to stand for 8 hours, and the adsorbent that had completed the adsorption was taken out and the supernatant was discharged at the same time to complete the primary repair; the modified clay mineral adsorbent was Mongolian Lightweight ceramsite made of a mixture of destoned clay modified adsorbent, chitosan modified clay, bentonite modified clay, and phosphoric acid modified attapulgite...

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Abstract

The invention discloses a two-level remediation method of heavy metal contaminated soil. The method comprises the steps of breaking a heavy metal contaminated paddy field, irrigating the paddy field until a water logging layer on a soil layer is 10-15cm deep after breaking the 0.5-0.6m deep soil on the surface layer into soil lumps with sizes less than 2-3mm, adding a modified clay mineral adsorbent, mechanically stirring the adsorbent, standing for 6-8 hours, fishing out the adsorbent which floats on water and completes adsorption, and simultaneously discharging the supernatant, thus completing first-level remediation; then collecting adsorbed light ceramsites, eluting the ceramsites in a wastewater treatment plant, and then leaching 1-3 times by using pure water as an eluent, thus completing second-level remediation, wherein the amount of water used each time is 0.6-1 times the leachate added for the first time by volume. The method is simple to operate, is low in cost, has high removal efficiency, meets actual requirements, and has good popularization and application values.

Description

technical field [0001] The invention relates to the field of contaminated soil treatment, in particular to a method for repairing heavy metal polluted soil. Background technique [0002] Cadmium (Cd), mercury (Hg), and arsenic (As) are currently recognized as heavy metal elements that are harmful to the human body. They produce toxic effects on the human body by inhibiting the activity of enzymes. Due to various production activities of human beings, the degree of pollution to the ecological environment is increasing day by day, among which the pollution of soil has become a serious problem that cannot be ignored. Toxic heavy metal elements in agricultural land generally refer to five types of mercury, cadmium, arsenic, chromium, and lead. In the south, cadmium is the most toxic and harmful, and the problem of water and soil pollution in the Pearl River Delta is prominent. The soils in these areas are dominated by low-pH soils with variable charges, which have weak bufferin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/00B09C1/02B09C1/06B01J20/24B01J20/30
Inventor 牛晓君
Owner SOUTH CHINA UNIV OF TECH
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