Synergistic leaching solution for chromium slag left place with heavy metal polluted soil and applications thereof

A technology for contaminated soil and heavy metals, applied in the restoration of contaminated soil, application, soil conditioning materials, etc., can solve the lack of simultaneous removal, no synergistic leaching-plant joint restoration method, and the diversity of microbial ecological functions in the soil environment Take into account the recovery of stability and other issues, so as to improve the removal rate of leaching and promote the effect of desorption and release

Inactive Publication Date: 2020-02-28
INST OF SOIL SCI CHINESE ACAD OF SCI
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Problems solved by technology

Publication numbers: CN105127190A, CN106734169A, CN106583436A, CN105295932A, CN103949468A, CN103521513A respectively provide a method for repairing hexavalent chromium in chromium-contaminated soil, a treatment method and equipment for repairing hexavalent chromium-contaminated soil, and a method for repairing hexavalent chromium A leaching method for contaminated soil, a leaching agent for remediation of chromium-contaminated soil, a remediation method and a device, a method for heterotopic treatment of total chromium in chromium-contaminated soil, a leaching method for hexavalent chromium-contaminated soil, and the above-mentioned leaching agent Both use chemical acid reagents or surfactants. Although they can effectively remove the total chromium in the soil, they greatly disturb and destroy the diversity of soil microbial ecological functions, which is not conducive to the recovery of soil environmental functions after leaching; Publication numbers: CN110170512A, CN110170511A, CN106964642A, and CN107008747A respectively provide an ultrasonic leaching device and method suitable for chromium-contaminated soil ectopic remediation, a thermal elution device and method suitable for chromium-contaminated soil ectopic remediation, and a chromium-contaminated site Ultrasonic enhanced oxidation leaching joint repair method, a microwave enhanced oxidation leaching combined repair method for chromium-contaminated sites, such methods use ultrasonic, heating, oxidation, microwave and other synergistic auxiliary means to enhance the removal efficiency of leaching, However, it did not give the synergistic effect of the leaching agent during the implementation of the strengthening measures, nor did it take into account the restoration of the soil ecological environment function after leaching
[0006] Through relevant literature review and patent retrieval, no publication and acceptance of the synergistic leaching-plant joint restoration method for complex heavy metal-contaminated soil in the chromium slag legacy site has been found. The closest prior art to the present invention is the environment-friendly leaching method. Lotion repair technology, publication number: CN104492806A, CN102601106A, CN102247980A and CN104492806A, respectively provide a preparation method of chromium-contaminated soil composite leaching agent, chromium slag contaminated soil ectopic leaching repair equipment and repair method, a heavy metal chromium Contaminated soil leaching repair agent and a preparation method of chromium-contaminated soil compound leaching agent, this kind of leaching repair technology uses environmentally friendly biosurfactant or small molecule organic acid, but because the leaching technology itself is a kind of Physicochemical remediation techniques with strong external force will bring certain damage to the physical structure and biochemical properties of the soil after remediation. Therefore, the above four methods fail to take into account the restoration of the ecological function diversity of soil supporting microorganisms after leaching, and aim at The co-existence of various complex heavy metal pollutants in the soil of the chromium slag legacy site has not been considered.
[0007] The main defects in the existing technology are: lack of synergistic leaching technology for synchronous removal of various complex heavy metal pollutants in the soil of the chromium slag legacy site, poor environmental friendliness of the selected chemical leaching agent, incomplete removal of pollutants and leaching. The recovery effect of the ecological function of the soil environment after washing is not ideal, and the research and development of related collaborative supporting restoration technologies are obviously insufficient to follow up, so the market application prospects of existing technologies are not clear
[0008] The main reasons for the defects are: In recent years, a large number of chromium slag sites have appeared due to the closure and relocation of metal chromium and chromium salt production enterprises. Early scientific and technological personnel paid more attention to the pollution of high-concentration chromium in such soils, but ignored the chromium residues. There are a large number of chromium-containing ores and other heavy metal pollution in the associated minerals in the slag site, so there are relatively few remediation technologies for the simultaneous removal of complex heavy metal pollution in the chromium slag site; the existing remediation technologies are mainly for The original chromium farmland soil with relatively low pollution concentration, but for the site soil with high pollution concentration, the remediation effect cannot meet the remediation needs; the existing remediation technology is more concerned about the restoration of the diversity and stability of microbial ecological functions in the remediation soil environment. few

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  • Synergistic leaching solution for chromium slag left place with heavy metal polluted soil and applications thereof
  • Synergistic leaching solution for chromium slag left place with heavy metal polluted soil and applications thereof
  • Synergistic leaching solution for chromium slag left place with heavy metal polluted soil and applications thereof

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Experimental program
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Effect test

Embodiment 1

[0037] For total Cr concentration greater than 1000 mg kg -1 And less than 5000 mg kg -1 , Pb concentration greater than 1000 mg kg -1 And less than 2000 mg kg -1 , Cd concentration greater than 1 mg kg -1and less than 10 mg kg -1 Chromium slag left over polluted soil:

[0038] The test soil was collected from a chromium residue site in Tianqiao District, Jinan City, Shandong Province. The soil samples were air-dried, the impurities were sorted out, and the soil samples were passed through a 10-mesh sieve for later use. The basic physical and chemical properties of the soil are pH 7.9, organic matter content 32.7 g kg -1 , total nitrogen 1.1 g kg -1 , available nitrogen 35.2 mg kg -1 , total phosphorus 0.4 g kg -1 , available phosphorus 31.6 mg kg -1 . The mechanical composition of the soil is 11.2 wt.% sand, 65.5 wt.% soil, and 23.3 wt.% clay. The background pollution concentrations of total chromium, hexavalent chromium and trivalent chromium in soil were 2343.1 ...

Embodiment 2

[0044] For total Cr concentration greater than 5000 mg kg -1 And less than 10000 mg kg -1 , Pb concentration greater than 2000 mg kg -1 And less than 5000 mg kg -1 , Cd concentration greater than 10 mg kg -1 And less than 100 mg kg -1 Chromium slag left over polluted soil:

[0045] The test soil was collected from a chromium slag legacy site in Luzhou City, Sichuan Province. The soil samples were air-dried, the impurities were sorted out, and the soil samples were passed through a 10-mesh sieve for later use. The basic physical and chemical properties of the soil are pH 8.1 and organic matter content 12.5 g kg -1 , total nitrogen 1.6 g kg -1 , available nitrogen 28.3mg kg -1 , total phosphorus 0.2 g kg -1 , available phosphorus 31.2 mg kg -1 . The mechanical composition of the soil is 15.4 wt.% sand, 64.2 wt.% soil, and 20.4 wt.% clay. The background pollution concentrations of total chromium, hexavalent chromium and trivalent chromium in soil were 8490.9 ±453.5 mg...

Embodiment 3

[0051] For total Cr concentration greater than 10000 mg kg -1 , Pb concentration greater than 5000 mg kg -1 , Cd concentration greater than 100 mgkg -1 Chromium slag left over polluted soil:

[0052] The test soil was collected from a site left over from chromium slag in Changsha City, Hunan Province. The soil samples were air-dried, the impurities were sorted out, and the soil samples were passed through a 10-mesh sieve for later use. The basic physical and chemical properties of the soil are pH 8.5, organic matter content 26.6 g kg -1 , total nitrogen 2.1 g kg -1 , available nitrogen 42.1mg kg -1 , total phosphorus 0.3 g kg -1 , available phosphorus 23.6 mg kg -1 . The soil mechanical composition is 18.9 wt.% sand, 69.2 wt.% loam, and 11.9 wt.% clay. The background pollution concentrations of total chromium, hexavalent chromium and trivalent chromium in soil were 14467.3 ±1543.2 mg kg -1 , 12938.3 ± 1345.3 mg kg -1 and 1529.5 ± 121.3 mg kg -1 . The background po...

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Abstract

The invention discloses a synergistic leaching solution for a chromium slag left place with heavy metal polluted soil and applications thereof. The application method comprises following steps: at first, grinding and sieving polluted soil particles; then placing the soil particles in a soil polybasic ex-situ leaching-repairing facility; adding an amino beta-cyclodextrin and sophorolipid mixed leaching solution, at the same time, adopting an ultrasonic enhancing and heating mode to carry out continuous ex-situ synergistic leaching; planting conyza canadensis on the leached soil, applying a nutritional buffer solution, which accounts for 5 to 10 mass% of the soil, to the soil, and carrying out artificial culture. After the growth of conyza canadensis, the repairing is finished. The providedleaching solution can remove multiple heavy metals in soil such as chromium, cadmium, lead, and the like. Due to the plantation of conyza canadensis and addition of exogenous nutritional substances, the ecological environment and ecological diversity of soil can be recovered rapidly.

Description

technical field [0001] The invention belongs to the technical field of remediation of compound heavy metal polluted soil in chromium slag leftover sites, and specifically relates to a synergistic eluent for compound heavy metal polluted soil in chromium slag leftover sites and an application thereof. Background technique [0002] In recent years, with the in-depth implementation of policies such as "retreating from the second to the third" and "retreating from the city to the garden", there have been a large number of chromium slag sites left behind due to the closure and relocation of metal chromium and chromium salt production enterprises in many suburbs. The high-concentration and high-toxicity compound heavy metal pollutants left in the soil of the site have brought serious risks to the ecological environment and human health; according to statistics, after the founding of the People's Republic of my country, the remaining sites with a residual volume of more than 5 mill...

Claims

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Application Information

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IPC IPC(8): C09K17/18B09C1/08B09C1/02
CPCB09C1/02B09C1/08C09K17/18
Inventor 叶茂黄丹张忠云祁慧鵷冯宁沙卞永荣蒋新
Owner INST OF SOIL SCI CHINESE ACAD OF SCI
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