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Reduction-stabilization two-stage type remediating method for chromium-contaminated soil

A technology of chromium-contaminated soil and a remediation method, which is applied in the field of reduction-stabilization two-stage remediation of chromium-contaminated soil, can solve the problems of long bioremediation method remediation period, great harm to operators, poor stabilization effect, etc. Poor stabilization effect, enhanced stabilization effect, and toxicity reduction effect

Inactive Publication Date: 2016-01-06
LIAONING UNIVERSITY OF PETROLEUM AND CHEMICAL TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these treatment technologies have certain limitations, such as the high cost of the soil replacement method; the leaching method is prone to secondary pollution and is more harmful to the operators; the reduction method can only reduce the toxicity of chromium to a certain extent; The remediation method has a long remediation cycle and slow progress, and is restricted by various environmental conditions; the stabilization / stabilization method has generally poor stabilization effects on Cr(Ⅵ) in soil

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] In this embodiment, the contaminated soil of a chemical plant chromium slag stacking site is selected for remediation experiment. The concentration of Cr(Ⅵ) in the tested soil is 1851.5 mg / kg, and the total Cr concentration is 12251.4 mg / kg. The method of the present invention is used for remediation treatment. The steps are as follows.

[0023] 1) After the soil sample is air-dried, pick out the stones, grass roots and other debris, break the soil particles to make the particle size less than 0.5cm, weigh 1500g of contaminated soil, put it in a plexiglass container, and add Reducing agent (reducing agent contains alkaline activator Ca(OH) 2 And hexavalent chromium reducing agent NaHSO 3 ), in mass percent, where NaHSO 3 90%, Ca(OH) 2 Accounted for 10%. The molar ratio of the reducing agent to Cr(Ⅵ) in the polluted soil was 9, so that it was evenly mixed with the soil, and an appropriate amount of distilled water was added to adjust the soil humidity to 25%, and a pl...

Embodiment 2

[0030] In this embodiment, artificially prepared polluted soil is selected for remediation experiment, and the effect of the method of the present invention in simulating the emergency treatment of sudden soil pollution accidents is investigated. The prepared soil adopts exogenous addition of K 2 Cr 2 o 7 The basic situation of the contaminated soil is shown in Table 3.

[0031] Table 3 shows the basic situation of polluted soil.

[0032] Test indicators Organic matter (%) pH Cr(VI) (mg / kg) Total Cr(mg / kg) polluted soil 1.95 7.7 893 1093.4

[0033] The restoration operation steps and main index test methods of the present embodiment are all the same as those in Example 1, the difference is that: 1) the contaminated soil used is the above-mentioned artificially prepared soil; 2) in terms of mass percentage, the hexavalent chromium reducing agent NaHSO 3 85%, alkaline activator Ca(OH) 2 15%; 3) In terms of mass percentage, the soluble phosphate...

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Abstract

The invention belongs to the technical field of environment protection, and relates to a remediating technology for chromium-contaminated soil, in particular to a reduction-stabilization two-stage type remediating method for the chromium-contaminated soil. The method sequentially comprises the following steps that (1) after a chromium reducing agent and the chromium-contaminated soil are evenly mixed, the humidity of the soil is adjusted to 20%-40%, chromium in the soil and the chromium reducing agent fully react for 0.5-5 days, and the content of Cr (VI) in the soil is lowered to below 150 mg / kg, namely remediation of the reduction stage is completed; and (2) chromium stabilizing agents are added into the contaminated soil after reduction through the step (1), the chromium stabilizing agents and the soil are evenly mixed, the humidity of the soil is still kept at 20%-40%, and the soil is stabilized for 15-60 days, namely the stabilization stage of the chromium-contaminated soil is completed. By means of the method, the toxicity of the chromium can be lowered, and the total leaching concentration of the chromium in the soil is greatly lowered; the method can be used for ex-site remediation and in-site remediation, and is a rapid and efficient chromium-contaminated soil remediating method.

Description

technical field [0001] The invention belongs to the restoration technology of chromium-contaminated soil in the technical field of environmental protection, and specifically relates to a two-stage restoration method of reduction-stabilization of chromium-contaminated soil. Background technique [0002] With the development of industry and society, the demand for chromium in human production and life is increasing year by year, and the world's chromium production is increasing day by day. Wastewater, sludge, waste gas, etc. produced in leather processing, electroplating industry, paint and pigment production, printing and dyeing industry, pharmaceutical and organic synthesis industries contain chromate or a large amount of chromium residue. By 2000, the total world production of hydrated sodium dichromate was about 740 kilotons. Chromate and its compounds are highly corrosive, highly toxic to animals, plants and microorganisms, and have lethal, carcinogenic and teratogenic e...

Claims

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Application Information

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IPC IPC(8): B09C1/08
CPCB09C1/08
Inventor 魏小娜李法云
Owner LIAONING UNIVERSITY OF PETROLEUM AND CHEMICAL TECHNOLOGY
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