Chromium-polluted soil cleaning method enhancing ion migration

A technology for chromium-contaminated soil and ion migration is applied in the field of cleaning chromium-contaminated soil by means of electro-enhanced ion migration, which can solve problems such as poor treatment effect of the cleaning method and achieve the effect of high treatment cost.

Inactive Publication Date: 2010-10-06
SHENYANG INST OF APPLIED ECOLOGY - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Factors restricting the effect of cleaning and repairing contaminated soil mainly include soil texture characteristics, pollutant types and occurrence status, etc. For soil with too fine texture, the cleaning method is not effective.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Pretreatment: First, remove stones and other sundries in the polluted soil, crush large soil clods, and pass through a 5mm sieve; secondly, add the treated polluted soil into the treatment column in batches (the inner diameter of the treatment column is 8cm, and the height is 35cm), and finally Electrodes are applied on both sides of the column, wherein the anode is a porous graphite electrode and the cathode is a porous graphite electrode.

[0021] The enhanced ion migration leaching method of the present invention: first, the contaminated soil after the above treatment, i.e. the hexavalent chromium-contaminated soil prepared in the laboratory, 1.5kg of the hexavalent chromium-contaminated soil is added to the treatment column-leaching column in five times for compaction ;

[0022] Secondly, it is advisable to add cleaning liquid through the applied direct current to cover 5-10cm of soil, the acceleration of cleaning liquid droplet is controlled at 1-5mL / min, and the v...

Embodiment 2

[0029] The enhanced ion migration cleaning method of the present invention: the polluted soil is taken from the soil samples around the chromium slag storage site of a certain chemical plant, and added in batches to the treatment column-cleaning column for compaction;

[0030] Next, choose 0.1mol / L citric acid-sodium citrate buffer solution, cleaning solution with pH 4.0, apply direct current, add cleaning solution to submerge 6cm of soil, control the droplet velocity of cleaning solution at 3mL / min, and voltage gradient of 5V / cm. After 2 hours of electrification, the chromium ions in the polluted soil are directional migrated under the action of a DC electric field with the assistance of the cleaning solution, and the cleaning solution is continuously added, and then the electricity is left to stand, so that the concentration of pollutants in the soil reaches the target, and the anode The area is used as the cleaning solution enrichment area, and the free heavy metals in the ...

Embodiment 3

[0033] The enhanced ion migration cleaning method of the present invention: the polluted soil is the trivalent chromium polluted soil prepared in the laboratory.

[0034] Secondly, choose distilled water as the cleaning solution, add the cleaning solution through the applied direct current to submerge the soil for 10cm, control the droplet velocity of the cleaning solution at 5mL / min, and the voltage gradient is 3V / cm. With the assistance of the direct current electric field, the water in the cleaning solution is electrolyzed on the electrode surface under the action of the electrode, and the anode generates a large amount of hydrogen ions to acidify the polluted soil, accelerate the directional migration of heavy metal ions in the soil to dissolve them, and make the cathode area As a cleaning solution enrichment area; then continue to add cleaning solution, and then energize, so that the concentration of pollutants in the soil reaches the target, the cathode area is used as a ...

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PUM

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Abstract

The invention relates to technology for cleaning heavy metal-polluted soil, in particular to a chromium-polluted soil cleaning method enhancing ion migration. The method comprises the following steps of: inserting an electrode into soil to be cleaned; applying a direct current electric field to the soil; injecting cleaning liquid into the polluted soil to make chromium ions in the polluted soil migrate directionally under the action of electric field force; continuing to add the cleaning liquid; standing and electrifying the polluted soil; and performing the previous steps circularly until the pollutant concentration of the soil reaches a treatment target. The method has the advantages of solving the problem of slow qualitative migration of heavy metal pollutants in low-permeability polluted soil, shortening repair time and recycling chromium-containing cleaning liquid.

Description

technical field [0001] The invention relates to the remediation of chromium-contaminated soil, in particular to a process of cleaning chromium-contaminated soil by means of electro-enhanced ion migration. Background technique [0002] Heavy metal polluted soil cleaning technology is the process of using fluid (usually liquid) to remove soil pollutants. The heavy metals in the soil solid phase are transferred to the soil liquid phase through ion exchange, adsorption and chelation, and then the wastewater is treated to recover heavy metals. and extractant process. The cleaning fluid is mainly acid-base solvent, surfactant, chelating agent, etc., and the cleaning equipment is generally pressure-driven equipment or mud cleaning equipment; according to the soil cleaning location, it can be divided into in-situ or ex-situ cleaning and repair. [0003] (1) In-situ cleaning and remediation of heavy metal contaminated soil [0004] Cleaning and in-situ remediation of heavy metal-co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/08
Inventor 郭书海李淑彩李刚
Owner SHENYANG INST OF APPLIED ECOLOGY - CHINESE ACAD OF SCI
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