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Method for restoring cadmium-contaminated farmland soil

A technology that pollutes soil and heavy metals and is applied in the restoration of polluted soil to achieve the effects of eliminating environmental pollution risks, ensuring safe production, and protecting integrity

Inactive Publication Date: 2016-03-02
中国有色桂林矿产地质研究院有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The invention patent with publication number CN103143556A discloses a passivator for reducing cadmium activity in acidic vegetable soil and its application method. The invention uses lime, humic acid and rice husk carbon as passivators to solidify cadmium-contaminated soil. The result of embodiment shows that the solidification rate of cadmium after repairing is 30~40%, but the content of cadmium in the soil after repairing by the method described in this invention does not reduce, but only changes the existing form of cadmium in soil, in natural There is a risk of re-transformation into the available state of cadmium under the condition of changing environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] (1) Naturally air-dry the farmland soil (with a Cd content of 1.1mg / kg, pH=6.5) collected from a lead-zinc mining area in Guilin, Guangxi, and grind it through a 10-mesh analytical sieve to remove large-grained stones and plant roots in the soil Non-earth impurities;

[0018] (2) Get ferric chloride and ammonium chloride and add water and be mixed with rinse agent, wherein, the concentration of ferric chloride and ammonium chloride is respectively 1.0% (w / w) and 0.5% (w / w);

[0019] (3) Take 20g of contaminated soil and put it into a 250ml Erlenmeyer flask, add 100ml of prepared eluent at a ratio of 5ml:1g according to the liquid-solid ratio, and use a stirrer to carry out stirring reaction at room temperature for 1.0h, and the stirring rate is controlled at 150r / min;

[0020] (4) Suction filter the leached soil to complete the solid-liquid separation. After the soil and the eluate are separated, slowly add 30ml of distilled water to the soil while suction filtering to...

Embodiment 2

[0030] (1) Naturally air-dry the farmland soil (with a Cd content of 0.83mg / kg, pH=6.5) collected from a mining area in Yangshuo, Guangxi, and grind it through a 10-mesh analytical sieve to remove non-soil such as large-grained stones and plant roots in the soil. impurities;

[0031] (2) Take ferric chloride and ammonium chloride and add water to prepare eluent, wherein the concentration of ferric chloride and ammonium chloride is 1.0% (w / w) and 0.5% (w / w);

[0032] (3) Take 20g of contaminated soil and put it into a 250ml Erlenmeyer flask, add 100ml of prepared eluent at a ratio of 8ml:1g according to the liquid-solid ratio, use a stirrer at room temperature to carry out stirring reaction for 1.0h, and the stirring rate is controlled at 170r / min;

[0033] (4) Suction filter the leached soil to complete the solid-liquid separation. After the soil and the eluate are separated, slowly add 30ml of distilled water to the soil while suction filtering to clean the eluent remaining ...

Embodiment 3

[0037] (1) The soil collected from a polluted farmland in Nandan, Guangxi (with a Cd content of 5.50 mg / kg, pH=6.0) was naturally air-dried, ground and passed through a 10-mesh analytical sieve to remove non-soil particles such as large stones and plant roots in the soil impurities;

[0038] (2) Use ferric chloride and ammonium chloride to compound the eluting agent, and the concentrations of ferric chloride and ammonium chloride are 1.0% (w / w) and 0.5% (w / w) respectively;

[0039] (3) Take 20g of contaminated soil and put it into a 250ml Erlenmeyer flask, add 100ml of prepared eluent at a ratio of 5ml:1g according to the liquid-solid ratio, and use a stirrer to carry out stirring reaction at room temperature for 1.0h, and the stirring rate is controlled at 160r / min;

[0040] (4) Suction filter the leached soil to complete the solid-liquid separation. After the soil and the eluate are separated, slowly add 30ml of distilled water to the soil while suction filtering to clean t...

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Abstract

The invention discloses a method for restoring cadmium-contaminated farmland soil. The method comprises the specific steps that cadmium in the contaminated soil is transferred and removed through a chemical elution mode, a mixed water solution of ferric chloride and ammonium chloride is adopted as an eluting agent during chemical elution, the mass concentration of ferric chloride ranges from 0.8% to 2.0%, and the mass concentration of ammonium chloride ranges from 0.5% to 1.5%. Ferric chloride and ammonium chloride are compounded to serve as the eluting agent, the cadmium removal rate is high, and especially when the cadmium-contaminated farmland soil with the cadmium content smaller than or equal to 1.1 mg / kg is restored, the content of cadmium in the restored soil can conform to the secondary standard GB15618-1995. The environmental pollution risk of the cadmium-contaminated farmland soil is thoroughly eliminated, and safety production of agricultural products is ensured. In addition, the prepared eluting agent can effectively protect the integrity of the soil structure, and the probability that the restored soil can be used for farming is ensured.

Description

technical field [0001] The invention relates to a method for repairing polluted soil, in particular to a method for repairing farmland soil polluted by heavy metal cadmium. Background technique [0002] In recent years, soil cadmium pollution incidents have occurred frequently in my country, such as the "cadmium rice" incident in Hunan, which has aroused widespread concern in the society, and the restoration and treatment of heavy metal-contaminated farmland soil is imminent. Cadmium is one of the "five poisons" with the most harmful effects of heavy metals. It is latent, persistent and irreversible, and has high biological toxicity. It is easier to be absorbed by crops than other heavy metals in the soil, enter the food chain, and endanger human health. [0003] At present, the remediation and treatment of cadmium-contaminated farmland soil mainly includes two research directions: one is to transfer and remove cadmium in the soil through chemical leaching, plant extraction,...

Claims

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Application Information

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IPC IPC(8): B09C1/02B09C1/08
CPCB09C1/02B09C1/08
Inventor 覃朝科农泽喜卢宗柳刘静静胡乔帆黄江波唐文杰
Owner 中国有色桂林矿产地质研究院有限公司
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