Method for repairing heavy metal contaminated soil by nanometer zero-valent iron

A nano-zero-valent iron and contaminated soil technology, applied in the field of environmental remediation, can solve the problems of little soil remediation effect, achieve the effect of reducing leaching toxicity and bioavailability, small time and economic cost, and simple operation

Inactive Publication Date: 2017-07-28
HUNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In recent years, in order to expand the application of nano-zero-valent iron in soil remediation, a lot of work on synthetic modification has been done, but the effect of applying to soil remediation is very little

Method used

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  • Method for repairing heavy metal contaminated soil by nanometer zero-valent iron
  • Method for repairing heavy metal contaminated soil by nanometer zero-valent iron
  • Method for repairing heavy metal contaminated soil by nanometer zero-valent iron

Examples

Experimental program
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Effect test

Embodiment 1

[0035] A nanometer zero-valent iron stabilized by sodium carboxymethylcellulose of the present invention is prepared by the following method:

[0036] (1) Nitrogen gas was passed through ultrapure water for 20 minutes to remove dissolved oxygen as a solvent for preparing the solution.

[0037] (2) Weigh 0.6g of sodium carboxymethylcellulose (CMC) in 100mL of water, seal and heat it in a water bath at 65°C, shake continuously to dissolve it, and after it cools down, deoxidize it with nitrogen for 20 minutes to obtain carboxymethylcellulose sodium solution.

[0038] (3) Weigh 7.4464g FeSO 4 ·7H 2 O was dissolved in 250mL water to obtain 0.107M FeSO 4 solution. Weigh 2.0266gNaBH 4 Dissolve in 250mL water to get 0.214M NaBH 4 solution.

[0039] (4) Take 25mL of FeSO with a concentration of 0.107M 4 The solution was immediately added to a 250mL three-neck flask equipped with 100mL sodium carboxymethylcellulose solution, and stirred while blowing nitrogen to obtain CMC-Fe 2...

Embodiment 2

[0048] A method for repairing heavy metal-contaminated soil through sodium carboxymethylcellulose-stabilized nano zero-valent iron of embodiment 1, comprising the following steps:

[0049] (1) Taken from the surface soil (0-25cm) on the banks of the Xiangjiang River in Changsha City, Hunan Province, and carried out pretreatment: remove impurities such as stones, branches and leaves, and pass through a 2mm sieve. The pH of the pretreated surface soil was 7.6, and the local contents of heavy metals Cd, Pb, Cu, and Zn in the soil were 22.5mg / kg, 167.10mg / kg, 30.25mg / kg, and 26.17mg / kg, respectively.

[0050] In order to make the experimental effect more obvious, four kinds of soil samples were designed by adding standard in heavy metal soil. The specific steps are as follows:

[0051] Cd-contaminated soil: Add heavy metal cadmium to the surface soil after the above pretreatment, so that the content of cadmium reaches 500mg / kg.

[0052] Pb-contaminated soil: Add heavy metal lead ...

Embodiment 3

[0072] A method adopting the stable nanometer zero-valent iron of embodiment 1 to remediate heavy metal-contaminated soil, the stable nanometer zerovalent iron made in embodiment 1 is passed into the soil contaminated with cadmium with a migration velocity of 0.0009cm / s respectively (Cadmium-contaminated soil composition is the same as embodiment 2) in the glass fiber reinforced plastic column (glass fiber reinforced plastic column specification and soil filling amount are identical with embodiment 2), pass into volume and be 6~10PV, collect effluent with part collector. The remediation effect is evaluated by the leaching toxicity test and bioavailability test of heavy metals in the soil after remediation, and the specific steps are the same as in Example 2. For inspection results, see Figure 4 .

[0073] Depend on Figure 4 It can be seen that with the increase of the volume of the stable nano-zero-valent iron suspension, the leaching toxicity and bioavailability treatment...

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Abstract

The invention discloses a method for repairing heavy metal contaminated soil by nanometer zero-valent iron. The method comprises the following steps of: filling heavy metal contaminated soil in a fiberglass-reinforced column; introducing water until constant weight is obtained; and introducing nanometer zero-valent iron suspension liquid in the fiberglass-reinforced column to perform elution on the heavy metal contaminated soil. Through the adoption of the method disclosed by the invention, heavy metal with high toxicity in the soil can be eliminated or reduced once under the condition that the original ecological structure of the soil is not damaged, and secondary contamination of nanometer zero-valent iron and heavy metal desorption are avoided; and the method has the advantages of being simple in treating technology, low in cost and obvious in treatment effect.

Description

technical field [0001] The invention relates to the technical field of environmental restoration, in particular to a method for restoring heavy metal-contaminated soil with nanometer zero-valent iron. Background technique [0002] In recent years, with the rapid development of industrialization and urbanization, the area of ​​cultivated land polluted by heavy metals such as Cd, Pb, Cu and Zn in my country is nearly 20 million hectares, accounting for about one-fifth of the total cultivated land area. Soil heavy metal pollution has become an issue that cannot be ignored. outstanding environmental issues. Studies have shown that even if the concentration of heavy metals in the soil is at a low level, it will still cause varying degrees of harm to macroscopic aquatic plants, algae, benthic animals, fish and microorganisms, and even affect food safety through food chain enrichment, indirectly affecting human beings. Health is a threat. Therefore, the remediation of heavy metal-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/02C09K17/40C09K101/00
CPCB09C1/02C09K17/40C09K2101/00
Inventor 黄丹莲胡正勋彭志威曾光明龚小敏王荣忠薛文静王茜秦香胡婵娟
Owner HUNAN UNIV
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