Soil extracting agent and preparation method thereof, and application of soil extracting agent in treatment of cadmium-contaminated soil

A technology of cadmium-contaminated soil and extractant, which is applied in the restoration of contaminated soil, application, soil conditioning materials, etc., can solve the problems of secondary pollution, secondary precipitation, and repair rate of less than 3%, and achieve a simple preparation and operation process , good adsorption performance and stable recovery

Inactive Publication Date: 2020-04-07
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, and 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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  • Soil extracting agent and preparation method thereof, and application of soil extracting agent in treatment of cadmium-contaminated soil
  • Soil extracting agent and preparation method thereof, and application of soil extracting agent in treatment of cadmium-contaminated soil
  • Soil extracting agent and preparation method thereof, and application of soil extracting agent in treatment of cadmium-contaminated soil

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] To prepare the soil extractant:

[0036] 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

[0037] Prepared by:

[0038] Step 1, preparing biomass carbon, using peeled wheat straw, after washing, air drying and crushing, the temperature was raised to 300°C under oxygen-limited conditions at an initial temperature of 25°C at a heating rate of 20°C / min. And after maintaining high temperature pyrolysis for 4 hours, airtight cooling to 25°C, removal of surface ash, and passing through 80-mesh sieve for later use.

[0039] Step 2, the composite process is as follows: 2-2.5 parts by mass of biochar pass through 80 mesh, put it into a 1L beaker, dissolve 2.5-3 parts by mass of ferric chloride hexahydrate in 150ml deionized water, and then take 1-1.1 parts by mass of One part of ferrous chloride tetrahydrate was dissolved in 50ml of deionized water, the two iron-containing sys...

Embodiment 2

[0041] 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. The proportion of TOC is 0.97%, pH6.36. The original moisture content is 4.77%, and the saturated moisture content is 30.16%.

[0042] The dosage of the soil extractant is 5% (mass ratio), and the specific test method is to select the magnetic biochar (0.3725g) made of 5g soil sample mixed with 0.25g biochar to test in a 50ml centrifuge tube, add 35ml deionized water , use, cover tightly and place on a shaker to oscillate at a speed of 110rpm. Samples were taken at 7 and 30 days, respectively.

[0043] The background concentration, concentration and removal rate of cadmium heavy metals after restoration are shown in Table 2. Among them: the total amount of cadmium in the soil was digested by the three-acid met...

Embodiment 3

[0048] The soil extractant that embodiment 1 is obtained will be used for soil sample pollution control in Hunan, and the soil extraction point is located in a certain county of Hunan Province to obtain soil at many points, and when the soil is obtained, the wheat straw stubble that does not have rot on the ground is removed, and the surface soil is about 20 cm deep . pH5.49. Table 3 shows the background concentration of cadmium heavy metals, the concentration after remediation and the removal rate. The original moisture content is 10.03%, and the saturated moisture content is 38.45%.

[0049] Table 3 The extraction effect of soil extractant on cadmium in Hunan soil Unit: mg / kg

[0050]

[0051]

[0052] According to the above data, the soil extractant can achieve a relatively good effect in 7 days for the treatment of cadmium-contaminated soil, and stabilize at this effect in 30 days. In the actual application process, the extraction of cadmium in the soil can be com...

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PUM

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Abstract

The invention discloses a soil extracting agent and a preparation method thereof, and application of the soil extracting agent in treatment of cadmium-contaminated soil. The soil extracting agent is formed by compounding biochar and magnetic powder, wherein a mass ratio of the biochar to the magnetic powder (in terms of Fe3O4) is (1.5-2.5): 1. When the adding mass of the soil extracting agent in the soil is 5%, the contamination concentration of cadmium is reduced by 20.1-24.0% in 7 days after the soil extracting agent is used for treating the cadmium-contaminated soil. In 30 days after the soil extracting agent is used for treating the cadmium-contaminated soil, the contamination concentration of cadmium is reduced by 26.2 to 28.3%.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to a soil extractant, a preparation method thereof and an application in treating cadmium-contaminated 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 t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K17/02B09C1/08B01J20/20
CPCB01J20/20B09C1/08B09C2101/00C09K17/02
Inventor 迟杰宫浩斐张璠丁铮
Owner TIANJIN UNIV
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