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A kind of remediation method of chromium polluted soil

A technology of chromium-contaminated soil and repair method, which is applied in the field of environmental protection, can solve the problems of easy harm to the environment, long repair time, strong migration, etc., and achieve the effect of good repair effect, low repair cost and wide source

Active Publication Date: 2016-05-11
中节能大地(杭州)环境修复有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Hexavalent chromium has high toxicity and strong mobility, so it is easy to harm the environment and threaten human health
Phytoremediation technology can reduce soil chromium content, but there are few plant species that can be used for chromium-contaminated soil remediation and their growth is greatly affected by the environment
In addition, phytoremediation technology also has problems such as long repair time and difficult harvesting and handling of plants, so the engineering application of this technology is seldom
Electric remediation technology is an emerging chromium-contaminated soil remediation technology, which can reduce the chromium content in soil, but it has the disadvantages of high energy consumption, many uncertain factors, and few engineering applications.

Method used

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  • A kind of remediation method of chromium polluted soil
  • A kind of remediation method of chromium polluted soil
  • A kind of remediation method of chromium polluted soil

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Excavate 100kg of chromium-contaminated soil with a hexavalent chromium concentration of 0.01mol / kg, and control the particle size of the soil block within 6cm by rolling and crushing. Put the crushed soil into the mixer, and while stirring, add 400mol iron powder according to the molar ratio of reducing agent and hexavalent chromium being 400:1. After stirring for 2 minutes, add 20L of water and stir for 3 minutes. Then, add 0.1 kg of magnesium oxide according to 0.1% of the mass of chromium-contaminated soil, and stir for 3 minutes. Mound the treated soil into a pile and cover with a rain cloth. After 1 day of curing, the treated soil was sampled for leaching toxicity testing, and HJ / T299 sulfuric acid nitric acid method was used for leaching. The test results showed that the leaching concentration of hexavalent chromium decreased from 20mg / L before treatment to 0.01mg / L after treatment; the leaching concentration of total chromium decreased from 25mg / L before treat...

Embodiment 2

[0033] Excavate 100kg of chromium-contaminated soil with a hexavalent chromium concentration of 0.01mol / kg, and control the particle size of the soil block within 8cm by rolling and crushing. Put the crushed soil into a mixer, and while stirring, add 380mol ferrous sulfate according to the molar ratio of reducing agent and hexavalent chromium being 380:1. After stirring for 3 minutes, 5 L of water was added and stirred for 4 minutes. Then, add 1kg of magnesium hydroxide according to 1% of the mass of chromium-contaminated soil, and stir for 3 minutes. Mound the treated soil into a pile and cover with a rain cloth. After 1 day of curing, the treated soil was sampled for leaching toxicity testing, and HJ / T299 sulfuric acid nitric acid method was used for leaching. The test results showed that the leaching concentration of hexavalent chromium decreased from 20mg / L before treatment to 0.015mg / L after treatment; the leaching concentration of total chromium decreased from 25mg / L b...

Embodiment 3

[0034] Excavate 100kg of chromium-contaminated soil with a hexavalent chromium concentration of 0.01mol / kg, and control the particle size of the soil block within 6cm by rolling and crushing. Put the crushed soil into a mixer, and while stirring, add 350mol of ferrous nitrate according to the molar ratio of reducing agent and hexavalent chromium being 350:1. After stirring for 5 minutes, add 25L of water and stir for 5 minutes. Then, add 5kg of calcium oxide according to 5% of the mass of chromium-contaminated soil, and stir for 3 minutes. Mound the treated soil into a pile and cover with a rain cloth. After 1 day of curing, the treated soil was sampled for leaching toxicity testing, and HJ / T299 sulfuric acid nitric acid method was used for leaching. The test results showed that the leaching concentration of hexavalent chromium decreased from 20mg / L before treatment to 0.01mg / L after treatment; the leaching concentration of total chromium decreased from 25mg / L before treatme...

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Abstract

The invention discloses a method for restoring chromium-polluted soil. The method comprises the following steps of crushing the chromium-polluted soil to obtain the grain diameter being less than 10cm; adding the crushed chromium-polluted soil into a reducing agent and water, and uniformly mixing to obtain reduced chromium-polluted soil, wherein the molar ratio of the reducing agent to hexavalent chromium in the chromium-polluted soil is (50-400):1, and the water is 5 to 25 percent by mass of the chromium-polluted soil; adding a stabilizer into the reduced chromium-polluted soil, wherein the stabilizer is 0.1 to 20 percent by mass of the chromium-polluted soil, uniformly stirring the stabilizer and the chromium polluted soil, insulating the air, and humidifying and maintaining the mixture for 1 to 3 days. By adopting the method, the restoring cost is low; the restoring speed is high; the restoring effect is good; the restored soil is leached by adopting a strict HJ / T299 sulfuric acid / nitric acid method, and the concentration of the hexavalent chromium in the leached liquid is lower than the fourth category surface water standard; the secondary pollution can be avoided.

Description

technical field [0001] The invention belongs to the technical field of environmental protection and relates to a method for repairing chromium-contaminated soil. Background technique [0002] Soil chromium pollution mainly comes from industrial waste residues such as chromium ore, metal smelting, electroplating, tanning, pigment and chemical industry. Hexavalent chromium has high toxicity and strong mobility, so it is easy to harm the environment and threaten human health. Trivalent chromium has low toxicity and almost completely precipitates in neutral and weakly alkaline solutions, so it is less harmful to the environment and humans. Chromium also has a great influence on the growth of crops. According to experiments, chromium in water can stimulate crop growth at 1ppm, slow down crop growth at 1-10ppm, and almost stop crop growth at 100ppm. In recent years, serious chromium pollution incidents have occurred in Hunan, Henan, Fujian and other places, causing heavy econom...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B09C1/00B09C1/08
Inventor 张文辉肖愉马力
Owner 中节能大地(杭州)环境修复有限公司