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Remediation method of hexavalent chromium polluted soil

A technology for chromium-contaminated soil and contaminated soil, applied in the direction of restoration of polluted soil, etc., can solve problems such as no research and report, inability to obtain soil hexavalent chromium content detection results, interference with soil hexavalent chromium detection, etc. The effect of reducing pipeline blockage and promoting recovery

Active Publication Date: 2021-12-24
CHONGQING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, FeS and elemental sulfur will seriously interfere with the detection of hexavalent chromium in soil, making it impossible to obtain qualified test results of hexavalent chromium in soil
Due to the above shortcomings, the reduction process under alkali immersion + alkaline conditions has not been studied and reported so far.

Method used

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  • Remediation method of hexavalent chromium polluted soil

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032]Repair the contaminated soil of chromium slag storage yard (the soil comes from the contaminated soil of a chromium slag storage yard, its hexavalent chromium content is 630mg / kg, and the moisture content is 4.1%). The technological process in the restoration process is as follows figure 1 As shown, the specific repair method includes the following steps:

[0033] (1) Preparation of lye containing soluble carbonate: add sodium carbonate and sodium hydroxide to water to form lye containing 0.3mol / L sodium carbonate and 0.5mol / L sodium hydroxide, which are stored at room temperature respectively In the lye tank and the high temperature lye tank (the high temperature lye tank has its own heating device);

[0034] (2) Soak the polluted soil in the soaking lye tank containing lye in step (1) for 5 days, carry out solid-liquid separation with a dehydrator to obtain lye (return to the soaking lye tank for the next batch of soil to be repaired soaking) and dehydrated soil I;

...

Embodiment 2

[0040] To remediate a certain chromium-contaminated soil with a hexavalent chromium content of 215 mg / kg, the operation process of this embodiment is the same as that of Example 1, except that the time of normal-temperature alkali immersion and high-temperature alkali immersion is different:

[0041] (1) The time of alkali immersion at normal temperature is 20 days,

[0042] (2) The soaking time in high temperature alkali is 5 minutes.

[0043] The hexavalent chromium in the soil repaired by the above process was tested for this batch of soil, and the hexavalent chromium content was 9mg / kg.

Embodiment 3

[0045] For the polluted soil of chromium slag stockyard (from the industrial pollution site, the content of hexavalent chromium is 1250mg / kg, and the cubic volume is only 98m 3 ) for repair, the technological process in the repair process is as follows figure 2 As shown, the specific repair method includes the following steps:

[0046] (1) preparation contains the lye of soluble carbonate: sodium carbonate and sodium hydroxide are added in water, form the lye that contains the sodium carbonate of 1.0mol / L and the sodium hydroxide of 1.0mol / L;

[0047] (2) Soak 1000kg of chromium-contaminated soil to be repaired in a soaking tank containing 1000L of 90°C high-temperature lye in step (1) for 3h;

[0048] (3) After soaking, add 27.5 kg of glucose into the soaking tank, stir and react at 50° C. for 10 minutes, cool naturally, and then dehydrate in a sand filter to obtain repaired soil.

[0049] The hexavalent chromium in the soil repaired by the above process was tested for thi...

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Abstract

The invention relates to a remediation method for hexavalent chromium polluted soil, and belongs to the technical field of chromium pollution remediation. The remediation method of the hexavalent chromium polluted soil comprises the following steps: soaking the to-be-remedied chromium contaminated soil in alkali liquor, and then adding reducing sugar for reduction reaction to reduce hexavalent chromium in the soil into trivalent chromium, thereby reducing the toxicity of the soil. According to the remediation method, through alkali soaking and heating reduction under the alkaline condition, the reduction efficiency of the hexavalent chromium in the insoluble state is improved, and meanwhile the problems that soil is corroded, secondary pollution is caused to the soil by a residual reducing agent, and soil hexavalent chromium detection is interfered are solved.

Description

technical field [0001] The invention belongs to the technical field of chromium pollution restoration and relates to a restoration method for hexavalent chromium-contaminated soil. Background technique [0002] In the natural environment, chromium is represented as trivalent chromium (Cr 3+ ) exists in the form of carcinogens, and hexavalent chromium [Cr(VI)] comes from human industrial activities, and CrO 4 2- It exists in the form of acid radicals, its toxicity is nearly a thousand times that of trivalent chromium, and it is a carcinogen. Therefore, the most commonly used technical route for the remediation of chromium-contaminated soil is to reduce the hexavalent chromium in the soil to trivalent chromium to reduce the toxicity of the contaminated soil. [0003] According to whether the contaminated soil is excavated during the remediation process, the remediation methods can be divided into in-situ remediation (no excavation) and ex-situ remediation (excavation). In ...

Claims

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Application Information

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IPC IPC(8): B09C1/08
CPCB09C1/08
Inventor 李东
Owner CHONGQING UNIV
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