Application of a Soil Extractant in Treating Lead Contaminated Soil

The technology of lead-contaminated soil and extractant is applied to the application field of soil extractant in the treatment of lead-contaminated soil, can solve the problems of secondary pollution, secondary precipitation, and repair rate of less than 3%, and achieves simple and convenient preparation and operation process. The effect of good adsorption performance and stable recovery rate

Active Publication Date: 2022-03-22
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the remediation of heavy metal-contaminated soil has just started in my country, and the current remediation rate is less than 3%.
However, the heavy metals after passivation still remain in the soil, there is a risk of secondary precipitation, and the pollution control of heavy metals is not thorough enough
The second is removal, which removes heavy metals from the soil to achieve the purpose of cleaning the soil; currently, super-accumulative plants are often used to extract heavy metals in the soil. Heavy metals are super-cumulatively extracted, and finally the ragweed is incinerated. The use of biological heavy metal adsorption treatment often has insufficient extraction capacity, and subsequent treatment will cause secondary pollution and other problems.

Method used

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  • Application of a Soil Extractant in Treating Lead Contaminated Soil
  • Application of a Soil Extractant in Treating Lead Contaminated Soil

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] To prepare the soil extractant:

[0027] The soil extractant is composed of biochar and magnetic powder. Among them, biochar and magnetic powder (with Fe 3 o 4 ) with a mass ratio of 2:1

[0028] Prepared by:

[0029] Step 1, preparing biomass carbon, using peeled wheat straw, after washing, air-drying, and crushing, the temperature is raised to 300°C under the condition of an initial temperature of 25°C and a heating rate of 20°C / min with limited oxygen. And after maintaining high temperature pyrolysis for 4 hours, airtightly cool to 25°C, remove surface ash, and pass through 80-mesh sieve for later use.

[0030] Step 2, the composite process is as follows: 2-2.5 parts by mass of biochar passed through 80 mesh, put it into a 1L beaker, dissolved 2.5-3 parts by mass of ferric chloride hexahydrate in 150ml deionized water, and then took 1-1.1 Parts by mass of ferrous chloride tetrahydrate were dissolved in 50ml of deionized water, the two iron-containing systems wer...

Embodiment 2

[0033] In this example, the soil extractant obtained in Example 1 is used for soil pollution control in Jiyuan, Henan Province. The soil extraction point is located in Jiyuan, with a range of about 4 mu. The wheat stubble is removed, and the topsoil is about 20cm deep. TOC accounted for 0.97%. pH6.36. The original moisture content is 4.77%, and the saturated moisture content is 30.16%. The dosage of the soil extractant is 5% (mass ratio), and the specific test method is to select the magnetic biochar (0.3725g) made by mixing 0.25g biochar with 5g soil sample to test in a 50ml centrifuge tube, add 35ml to remove Ionized water, after use, cover tightly and shake on a shaker at 110rpm. Samples were taken for testing after 7 and 30 days.

[0034] Table 2 shows the background concentration, post-remediation concentration and removal rate of lead heavy metals. Among them: the total amount of lead in the soil is digested by the three-acid method, and the content of different for...

Embodiment 3

[0039] The soil extractant obtained in Example 1 is used for soil sample pollution control in Hunan. The soil extraction point is located in a certain county in Hunan Province. The soil is extracted from multiple points. When the soil is extracted, the wheat stalk stubble without rot on the ground is removed, and the surface soil is about 20 cm deep. . pH5.49. Table 3 shows the background concentration, post-remediation concentration and removal rate of lead heavy metals. The original moisture content is 10.03%, and the saturated moisture content is 38.45%.

[0040]Table 3 The effect of soil extractant on the extraction of lead in Hunan soil Unit: mg / kg

[0041]

[0042] According to the above data, the soil extractant can achieve a relatively good effect in 7 days for the treatment of lead-contaminated soil, and stabilize at this effect in 30 days. In the actual application process, the extraction of lead in the soil can be completed within 7 days of application.

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Abstract

The invention discloses the application of a soil extractant in treating lead-contaminated soil. The soil extractant is composed of biomass charcoal and magnetic powder. Among them, biochar and magnetic powder (with Fe 3 o 4 ) has a mass ratio of (1.5‑2.5):1. When the dosing mass of the soil extractant in the soil is 5%, the lead pollution concentration is reduced by 30.8-41.9% after the soil extractant treats the lead-contaminated soil for 7 days. In the above technical solution, when the weight of the soil extractant added to the soil is 5%, after the soil extractant treats lead-contaminated soil for 30 days, the concentration of lead pollution is reduced by 26.8-40.1%.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to the application of a soil extractant in treating lead-polluted soil. Background technique [0002] Soil is one of the main natural resources that human beings rely on for survival, and it is also an important part of the ecological environment. Due to the increasing scale of industrial and agricultural production, the waste water and waste residues are also increasing. These wastes not only destroy the surface vegetation, but also The toxic and harmful heavy metals in it will also enter the surrounding soil environment with the discharge of wastewater and the weathering and leaching of waste residue piles, affecting the growth of surface organisms, and can enter the human body and other animals through food chains and other channels for enrichment, affecting human health. [0003] The accumulation of heavy metals in farmland to a certain extent not only reduces t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B09C1/00
CPCB09C1/00
Inventor 迟杰宫浩斐丁铮张璠
Owner TIANJIN UNIV
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