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Chromium-polluted soil restoration leaching agent and chromium-polluted soil restoration method

A technology of chromium-contaminated soil and eluent, which is applied in the field of eluents for remediating chromium-contaminated soil, can solve the problems of low pH value of leaching solution, high price, increased elution repair cost, etc., and achieves high removal efficiency, good The effect of repair efficiency

Active Publication Date: 2015-05-13
SOUND ENVIRONMENTAL RESOURCES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the leaching repair methods published in patent documents (Application No.: 201210059303.1) and (Application No.: 201410158901.3), one or more organic acid mixtures are used as eluting agents, resulting in a low pH value of the eluate, which is not conducive to subsequent Removal of heavy metals and recycling of eluents
Patent literature (application number: 201310689172.X) uses 1% to 70% polyepoxysuccinic acid (PESA) as a leaching agent to repair chromium-contaminated soil, but PESA is an artificial chelating agent, the price is relatively high, if there is no A cost-effective recycling method will greatly increase the cost of rinsing and repairing
Patent literature (application number: 201310493630.2) discloses a method for leaching soil contaminated with hexavalent chromium. This method uses hydrochloric acid as the eluent, and the leaching and stirring are carried out for 3 to 6 hours. long question
The above patent documents are mainly aimed at hexavalent chromium, and less involved in total chromium in soil, especially trivalent chromium which is not easily leached.

Method used

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  • Chromium-polluted soil restoration leaching agent and chromium-polluted soil restoration method
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  • Chromium-polluted soil restoration leaching agent and chromium-polluted soil restoration method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Accurately weighed 50.00g of contaminated clay from an electroplating factory in Shiyan City, Hubei Province that was passed through a 2mm sieve. The concentration of heavy metal chromium in the soil was 4346.82mg / kg, of which hexavalent chromium accounted for 94.8%. 2 O, 3.48g / LSDBS solution, containing 3.48g / L SDBS and 24g / L H 2 o 2 The mixed solution was used as eluting agent, processed in an ultrasonic processor with a power of 720W and a frequency of 20kHZ, and 5ml of mud was taken at 1, 2, 4, 8, 14, 22, 30, 40, and 50min, and centrifuged at 3000×g After 20 minutes, pass through a 0.45 μm filter membrane, and measure the content of heavy metal chromium in the filtrate. Three parallels were performed for each treatment, and the results were averaged.

[0024] The removal efficiency (unit: %) of three kinds of leaching agents to total chromium in soil under the different treatment time of table 1

[0025]

Embodiment 2

[0027] Accurately weigh 50.00g of the contaminated clay left over from an electroplating factory in Shiyan City, Hubei Province through a 2mm sieve. The concentration of heavy metal chromium in the soil is 4346.82mg / kg, of which hexavalent chromium accounts for 94.8%. According to the solid-liquid ratio of 1:10, 3.48 g / L SDBS and 24g / L H 2 o 2 The mixed solution was used as eluting agent, treated in ultrasonic processor with power of 480W, 720W, 960W and frequency of 20kHZ respectively, and 5ml mud was taken at 1, 2, 4, 8, 14, 22, 30, 40, 50min respectively, Centrifuge at 3000×g for 20 minutes, pass through a 0.45 μm filter membrane, and measure the content of heavy metal chromium in the filtrate. Three parallels were performed for each treatment, and the results were averaged.

[0028] The removal efficiency (unit: %) of total chromium in soil under table 2 different treatment time and power

[0029]

Embodiment 3

[0031] Take 20ml and process it according to the above method to obtain leachate in a 50ml plastic centrifuge tube, the concentration of total chromium in the leachate is 430.0mg / L, add 0.06, 0.08, 0.10, 0.12, 0.16, 0.2g sulfuric acid heptahydrate respectively For ferrous iron, at room temperature and 150rpm, oscillate in a water bath constant temperature oscillator for 20min, centrifuge at 3000×g for 20min, pass through a 0.45μm filter membrane, and measure the content of heavy metal chromium in the filtrate. Three parallels were performed for each treatment, and the results were averaged.

[0032] Table 3 The removal rate of total chromium in the leachate under different ferrous sulfate heptahydrate additions

[0033] Amount of ferrous sulfate heptahydrate added (g)

[0034] As can be seen from the above three groups of embodiments, the use of the leaching agent of the present invention in combination with ultrasonic strengthening treatment has a good repair effect...

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Abstract

The invention discloses a chromium-polluted soil restoration leaching agent and a chromium-polluted soil restoration method, and belongs to the technical field of environmental remediation. The leaching agent comprises sodium dodecyl benzene sulfonate, hydrogen peroxide and water, and the sodium dodecyl benzene sulfonate, hydrogen peroxide and water are mixed into a hybrid solution. The invention also discloses a chromium-polluted soil restoration method which is as follows: mixing screened chromium-polluted soil with the chromium-polluted soil restoration leaching agent, processing by use of an ultrasonic processor, standing, taking supernatant as a leaching solution; adding a solid reducing agent into the leaching solution to reduce dissolved hexavalent chromium into trivalent chromium sediment, separating the sediment, and centrally treating the sediment containing trivalent chromium and iron element to complete the ultrasound enhanced remediation of chromium-polluted soil. The removal rate of chromium in the polluted soil can reach 95% above by the method. By use of the sodium dodecyl benzene sulfonate and hydrogen peroxide mixed leaching agent for chromium-polluted soil leaching and restoration, the method has the characteristics of high total chromium remediation efficiency, short processing time and the like.

Description

technical field [0001] The invention relates to the technical field of environmental remediation, in particular to a leaching agent and a method for remediating chromium-contaminated soil. Background technique [0002] With the development of my country's chrome ore mining, smelting, chromium salt manufacturing, electroplating, leather, printing and dyeing and other related industries, a large amount of chromium elements have entered the soil and groundwater environment along with the industrial "three wastes", especially the large amount of chromium slag piles, bringing enormous pressure to the surrounding ecological environment and human health. In polluted sites, the total chromium in the soil (mainly in hexavalent and trivalent forms) can reach 10500mg / kg (of which the concentration of hexavalent chromium can reach 10000mg / kg), far exceeding my country's "Soil Environmental Governance Standards" ( GB 15618-1995) level 3 standard 400mg / kg, while the pollution depth can rea...

Claims

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Application Information

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IPC IPC(8): C09K17/40B09C1/02
CPCB09C1/02C09K17/40
Inventor 崇忠义蔡红文一波
Owner SOUND ENVIRONMENTAL RESOURCES
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