Method for repairing cadmium-lead composite polluted calcareous soil

A technology for calcareous soil and compound pollution, applied in the field of heavy metal pollution soil remediation, can solve the problems of secondary pollution, long remediation period, easy damage to soil structure, etc., and achieves the effect of maintaining stability and reducing heavy metal content

Active Publication Date: 2012-08-01
CENT SOUTH UNIV +1
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AI Technical Summary

Problems solved by technology

The bioremediation method has the advantages of low treatment cost and high cleaning level, but the required repair period is long and the type of pollution is limited; the electric restoration method is costly, complex and huge in operation equipment, and is not conducive to large-scale remediation. Repair; leaching method is expensive, easy to cause secondary pollution, easy to damage the soil structure, etc.
The fixation method can reduce heavy metal mobility and bioavailability, but some fixatives themselves have secondary pollution, and the long-term fixation effect is unstable, and many existing fixatives have no obvious treatment effect on calcareous polluted soil

Method used

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  • Method for repairing cadmium-lead composite polluted calcareous soil

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Embodiment 1

[0028] Embodiment 1: remediation of cadmium-lead compound polluted calcareous soil

[0029] Weigh 5Kg of contaminated soil in Dongdagou, Baiyin City, Gansu Province, crush it to less than 2cm, put it into a 15-liter plastic container, and add 1KgAl 2 (SO 4 ) 3 18H 2 O and 200g polyferric sulfate (PFS), after mixing evenly, add 10LH 2 O, stir, let stand for 1d, and collect the filtrate by filtration. Determination of Cd and Pb content in soil and filtrate. Filtrate with 10% Ca(OH) 2 Adjust the pH to 9.0, add 5ml / L 0.1% polyacrylamide (PAM) and stir, let stand for 1h, filter, and reuse the filtrate. The contents of DTPA-extracted Cd and Pb in the soil were reduced from 5.82mg / kg and 89.15mg / kg to 0.93mg / kg and 18.31mg / kg respectively, and the removal rate of DTPA-extracted Cd was 84%. The removal rate of elevated Pb was 79%.

Embodiment 2

[0030] Example 2: Remediation project of cadmium-lead compound polluted soil in Dongdagou, Baiyin City, Gansu Province

[0031] The polluted farmland soil in Dongdagou, Baiyin City, Gansu Province was crushed to less than 2cm with a rotary tiller, and the crushed soil was built into a mound with a thickness of less than 20cm, and a plastic film was spread underneath to prevent leakage; Al, which accounted for 18% of the soil mass, was added 2 (SO 4 ) 3 18H 2 O and polyferric sulfate (PFS) accounting for 8% of the soil quality, fully mix the soil and the agent with a rotary tiller, add the Yellow River irrigation water according to twice the soil quality, and stir to make the agent fully dissolve and react with the surface of the soil particles , after reacting for 1 day, drain and collect the supernatant. Use 10% Ca(OH)2 in the supernatant to adjust the pH to 9.0, add 5ml / L 0.1% polyacrylamide (PAM) to stir, let it stand for 1h, filter the sludge, collect the filtrate, and ...

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Abstract

The invention discloses a method for repairing cadmium-lead composite polluted calcareous soil. Heavy metals of cadmium and lead in the calcareous soil mainly exist in a carbonate combined state and an organic combined state which are more stable, treatment requirements are difficultly met by a chemical fixation method, and a conventional leaching repair method has the problems of serious damage to soil property and difficulty in leaching liquid treatment. In order to solve the problems, Al2(SO4)3 18H2O and polymeric ferric sulfate (PFS) are uniformly mixed with the soil according to a certain molar ratio and are soaked with water, filtrate is collected, the heavy metals in the filtrate are settled, and the soil can be circularly leached by supernate. The removal rate of available Cd in the polluted soil reaches 84.02%, the removal rate of available Pb in the polluted soil reaches 79.47%, and the repaired soil is beneficial to crop plantation.

Description

technical field [0001] The invention relates to the technical field of soil remediation polluted by heavy metals, in particular to the remediation of calcareous soil polluted by cadmium and lead compound. Background technique [0002] With the rapid development of the national economy, the demand for heavy metal resources in human society has increased rapidly, and heavy metal pollutants in industrial and mining waste residues, garbage, wastewater, petroleum, and pesticides have continuously entered the soil environment, causing some cultivated land to be polluted. Long-term stacking of heavy metal-contaminated soil will cause heavy metal pollutants to diffuse into groundwater, making the heavy metal content in groundwater exceed the standard and cannot be used. Heavy metals in the soil will also seriously affect the growth and quality of crops, and can enter the human body through direct contact with hands and mouth through dust, and heavy metals in the soil can easily ente...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/08
Inventor 杨志辉柴立元王庆伟闵小波廖映平史学峰苗旭峰张淑娟吴宝麟
Owner CENT SOUTH UNIV
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