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Oxidation-chelation leaching combined remediation method for Cr-contaminated soil

A technology for chromium-contaminated soil and contaminated soil, applied in the field of remediation of heavy metal pollution in site soil, can solve the problems of low removal rate of total Cr in soil, interference of subsequent chelation leaching, and low removal rate of total Cr, so as to improve repair efficiency and facilitate Effect of rinsing removal and improvement of removal rate

Active Publication Date: 2015-12-16
SHANDONG NORMAL UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to solve the problem of the low removal rate of total Cr in the soil and the use of H 2 o 2 In the oxidation treatment method, there are problems of low oxidation efficiency, interference with subsequent chelation leaching, and low removal rate of total Cr. After experimental research, the inventor provides a combined oxidation-chelation leaching repair technology for chromium-contaminated soil. This method not only has higher oxidation efficiency, but also does not affect the microwave oxidation method of subsequent chelation leaching, and then leaching with water or chelating agent can obtain higher remediation efficiency, especially suitable for remediation of contaminated soil with low Cr activity index and Cr-contaminated sites remediation

Method used

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  • Oxidation-chelation leaching combined remediation method for Cr-contaminated soil
  • Oxidation-chelation leaching combined remediation method for Cr-contaminated soil
  • Oxidation-chelation leaching combined remediation method for Cr-contaminated soil

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Experimental program
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Effect test

Embodiment 1

[0034] (1) After the Cr-contaminated soil is air-dried, grind, pass through a 2mm sieve, and set aside;

[0035] (2) According to the mass ratio of liquid to soil = 2.5:1, 10% H 2 o 2 Add to the Cr-contaminated soil pretreated in step (1), stir while adding, after mixing evenly, microwave at low level for 5 minutes; then add H 2 O to a mass ratio of liquid to soil of 6:1, vibrate or stir back and forth (180r / min) for 30 minutes, filter or centrifuge to remove the eluent.

[0036] (3) Chelate rinsing: 0.15MEDTA is adjusted to pH=10 with HCl and NaOH, according to liquid-soil mass ratio=10:1, joins in the Cr-contaminated soil that step (2) handles, reciprocating vibration or stirring ( 180r / min) for 60 minutes, filter or centrifuge to remove the eluent, and rinse 3 times according to the pollution situation.

Embodiment 2

[0038] (1) The present invention tries to use microwave-hydrogen peroxide oxidation-microwave-EDTA leaching in the research process, but the inventors found that microwave treatment is also used in the rinsing process, resulting in a decrease in rinsing efficiency, which may be due to microwave Heating causes partial EDTA to be oxidized and decomposed, which reduces the rinsing efficiency. Considering the complexity and cost of the process, microwave treatment is not used in the rinsing step in the method adopted in the present invention.

[0039] (2) Choice of eluent:

[0040] The present invention compares deionized water, DTPA, 0.1mol·L -1 HCl, 0.1mol L -1 Citric acid (CTA), 0.1mol·L -1 Disodium ethylenediaminetetraacetic acid (EDTA), 0.1mol·L -1 h 3 PO 4 , 0.1mol·L -1 CaCl 2 , 0.1mol·L -1 The leaching effects of 8 kinds of leaching agents of NaOH hydrochloric acid, wherein the leaching agents all have the effect of leaching to remove Cr; among them, EDTA has the be...

Embodiment 3

[0042] (1) After air-drying the Cr-contaminated soil, grind it, pass through a 1mm sieve, and set aside;

[0043] (2) Microwave-H 2 o 2 Oxidation: According to the mass ratio of liquid to soil = 2:1, 10% H 2 o 2 Add to the Cr-contaminated soil pretreated in step (1), stir while adding, after mixing evenly, microwave at low-grade for 3 minutes; then add H 2 O to a mass ratio of liquid to soil of 5:1, vibrate or stir back and forth (180r / min) for 20 minutes, filter or centrifuge to remove the eluent.

[0044] (3) Chelate leaching: 0.1MEDTA is adjusted to pH=9 with HCl and NaOH, according to the mass ratio of liquid to soil=9:1, join in the Cr-contaminated soil processed in step (2), vibrate or stir back and forth ( 180r / min) for 30 minutes, filter or centrifuge to remove the eluent, and rinse once according to the pollution situation.

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Abstract

The invention relates to an oxidation-chelation leaching combined remediation method for Cr-contaminated soil. The remediation method comprises the following steps: performing microwave treatment on a H2O2 oxidizing process: uniformly mixing a H2O2 aqueous solution with Cr-contaminated soil for microwave treatment; adding H2O for leaching, and removing leaching liquid; performing chelation leaching, that is, adding a chelating agent for chelation leaching, and removing Cr (VI) and part of Cr (III). Through adoption of the remediation method, Cr in soil can be effectively removed; the remediation method is suitable for Cr-contaminated soil remediation, is relatively high in oxidation efficiency, is a microwave oxidation method without affecting subsequent chelation leaching, and can realize relatively high remediation efficiency through leaching with water or the chelating agent.

Description

technical field [0001] The invention belongs to the technical field of remediation of site soil heavy metal pollution, and in particular relates to a method for combined oxidation-chelation leaching and remediation of chromium-contaminated soil. Background technique [0002] With the overall rapid advancement of the world's industrialization and urbanization process, environmental pollution is increasing day by day, and heavy metal pollution in soil is very serious, which has become a serious environmental problem facing the world. According to the "National Soil Pollution Survey Bulletin", the soil pollution in some areas of my country is relatively serious, the soil environmental quality of cultivated land is worrying, and the soil environmental problems of industrial and mining wasteland are prominent. In my country, 12 million tons of grain are polluted by heavy metals every year, causing direct economic losses of more than 20 billion yuan. Soil heavy metal pollution no...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/02B09C1/08
CPCB09C1/02B09C1/08
Inventor 成杰民李世业李华鹏
Owner SHANDONG NORMAL UNIV
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