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Repairing method of chromium polluted soil

A technology of chromium-contaminated soil and remediation method, which is applied in the field of remediation of contaminated soil, can solve the problems of low remediation rate, low generation rate, and secondary pollution, and achieve the goal of increasing iron content, increasing the generation rate, and improving the removal rate Effect

Inactive Publication Date: 2013-09-25
TIANJIN ACADEMY OF ENVIRONMENTAL SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, the rinsing method is a commonly used repair method with low cost and easy implementation, but its defect is: due to the Cr 6+ It is directly reduced to Cr in the unhydrolyzed state 3+ , so Cr 3+ The generation rate is low, resulting in a low repair rate of only about 60%. In addition, because the coagulant uses organic reagents, the soil introduces secondary pollution while removing chromium pollution. Furthermore, the repair agent used in the prior art will change soil matrix, deteriorating soil quality

Method used

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  • Repairing method of chromium polluted soil

Examples

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Effect test

Embodiment 1

[0015] In this example, the polluted soil in Dabizhuang, Dongli District, Tianjin City was selected, and the chromium content in the polluted soil was 92.24 mg / kg after detection by HJ 491-2009 "Determination of Total Chromium in Soil by Flame Atomic Absorption Spectrophotometry".

[0016] Adopt a kind of remediation method of chromium-contaminated soil provided by the invention, it is characterized in that comprising the steps:

[0017] ⑴. First crush the chromium-contaminated soil to a particle size of 1-2 cm, and then take 10 kg of it and put it into the reactor. In actual operation, a reactor with a mixer is used;

[0018] (2) Aluminum sulfate and basic ferric sulfate are added to the reaction kettle and mixed uniformly with 10kg of chromium-contaminated soil obtained from step (1), wherein the quality of aluminum sulfate accounts for 14% of the quality of the chromium-contaminated soil, which is 1400g. Formula ferric sulfate quality accounts for 6% of chromium polluted so...

Embodiment 2

[0027] In the present embodiment, the source of polluted soil selected, operation procedure, reaction mechanism and the measuring method of chromium content are all the same as embodiment 1, and difference is only: in step (2), aluminum sulfate quality accounts for 15% of chromium-contaminated soil quality, is 1500g Basic ferric sulfate quality accounts for 7% of chromium-contaminated soil quality, is 700g; In step (3), the mass ratio of adding water and chromium-contaminated soil mixture is 1.64:1; In step (4), the filtrate pH value is adjusted to 10.

Embodiment 3

[0029] In the present embodiment, the source of polluted soil selected, operation steps, reaction mechanism and the measuring method of chromium content are all the same as embodiment 1, the difference is only: in step (2), the quality of aluminum sulfate accounts for 16% of the mass of chromium-contaminated soil, which is 1600g Basic ferric sulfate quality accounts for 8% of chromium-contaminated soil quality, is 800g; In step (3), the mass ratio of adding water and chromium-contaminated soil mixture is 1.76:1; In step (4), the filtrate pH value is adjusted to 11.

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Abstract

The invention relates to a repairing method of chromium polluted soil. The repairing method is characterized by comprising the following steps: (1) smashing the chromium polluted soil to a granularity of 1-2 cm; (2) adding aluminum sulfate and ferric subsulfate into the chromium polluted soil, blending uniformly, wherein aluminum sulfate accounts for 14-18% by mass of the chromium polluted soil, and ferric subsulfate accounts for 6-10% by mass of the chromium polluted soil; (3) adding water, stirring the chromium polluted soil mixture, immersing for 2 days, filtering and collecting the filtrate, wherein the mass ratio of water to the chromium polluted soil mixture is 1.5:1-2:1, drying the obtained soil after filtration and getting repaired soil; (4) adding sodium hydroxide or potassium hydroxide into the collected filtrate, adjusting pH of the filtrate to 10-11, adding a flocculating agent to deposit chromium in the filtrate at the same time, standing and filtering out chromium in the filtrate, and the filtrated liquid is used as the water required in step (3). The beneficial effects of the repairing method comprise raising repair rate, preventing secondary pollution and maintaining soil matrix.

Description

technical field [0001] The invention relates to a restoration method of polluted soil, in particular to a restoration method of chromium-polluted soil. Background technique [0002] For many years, chromium pollution has become an important object of environmental pollution control because of its serious harm to human health. Chromium slag is the hexavalent chromium-containing Cr that is discharged from the chromium salt during the calcium roasting and leaching process. 6+ Solid waste belongs to heavy metal hazardous waste. Chromium, mercury, cadmium, lead, and arsenic are also known as the "five poisons" of heavy metal pollution. Cr in chromium slag 6+ It is one of the three internationally recognized carcinogenic metals and one of the 129 key pollutants recognized by the US EPA. According to statistics, about 600,000 tons of chromium slag are newly discharged in my country every year, and the cumulative stockpiled chromium slag has reached nearly 6 million tons over the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/08
Inventor 邓小文卢学强马建立焦永杰袁雪竹陈红张良运刘畅霍宁
Owner TIANJIN ACADEMY OF ENVIRONMENTAL SCI
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