Method for remedying arsenic polluted soil

A technology for arsenic pollution and soil, applied in the restoration of contaminated soil, etc., can solve the problems of inability to remove arsenic efficiently and reliably, and achieve efficient treatment and simple operation and management

Inactive Publication Date: 2010-11-10
CHINA UNIV OF GEOSCIENCES (BEIJING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the stabilization mechanism of the above substances to arsenic is mainly adsorption/desorption, under certain conditions,

Method used

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  • Method for remedying arsenic polluted soil
  • Method for remedying arsenic polluted soil
  • Method for remedying arsenic polluted soil

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] The experimental soil was collected from Haidian District, Beijing, and passed through a 20-mesh nylon sieve after air-drying, impurity removal and grinding. Add NaAsO to arsenic contaminated soil through artificial external sources 2 The form is configured. The artificially configured soil used in this example has an arsenic pollution intensity of 1151 mg / kg and a pH of 8.21. Set the following 7 experimental conditions:

[0049] 1. Fe / As=2, CaO%=0 (that is, no quicklime is added);

[0050] 2. Fe / As=4, CaO%=0;

[0051] 3. Fe / As=6, CaO%=0;

[0052] 4. Fe / As=8, CaO%=0;

[0053] 5. Fe / As=12, CaO%=0;

[0054] 6. Fe / As=16, CaO%=0;

[0055] 7. Fe / As=20, CaO%=0;

[0056] In this example, the stabilizer FeCl 3 They were added to the contaminated soil at the set molar ratio of Fe / As, and after stabilizing for 1 day, after a toxicity leaching experiment, it was found that as the molar ratio of Fe / As increased, the arsenic content in the leaching solution continued to decrease, and the stab...

example 2

[0058] The soil used in Example 2 was the same as that in Example 1. There are still 7 experimental conditions:

[0059] 1. Fe / As=3, CaO%=0.005%;

[0060] 2. Fe / As=3, CaO%=0.01%;

[0061] 3. Fe / As=3, CaO%=0.05%;

[0062] 4. Fe / As=3, CaO%=0.1%;

[0063] 5. Fe / As=3, CaO%=0.5%;

[0064] 6. Fe / As=3, CaO%=1%;

[0065] 7. Fe / As=3, CaO%=2%;

[0066] In this example, before using the stabilizer, first use quicklime to adjust the soil pH. When CaO was added to the contaminated soil at 0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 2% (mass ratio), the pH of the soil was 8.28, 8.50, 8.63 after being buffered by the soil system. , 9.06, 10.02, 11.52, 12.12. FeCl 3 Add the Fe / As molar ratio of 3 to the contaminated soil sample, keep the solid-to-liquid ratio at about 2:1, continue stirring for 20 minutes, and stabilize for 1 day. The stabilization effect of arsenic varies with soil pH image 3 . It can be seen from the figure that in the range of pH 8.28-10.02, with the increase of pH, the stabilization ...

Embodiment 3

[0068] The three soil samples used in this example are still collected from Haidian District and are artificially configured simulated soil samples. Its characteristics are shown in Table 1. The pH values ​​of soil samples S1, S2 and S3 were 9.41, 10.02, and 9.73 after being buffered by 0.1% quicklime. Then add FeCl with Fe / As=3 3 The solution was stable for 1 day. After the leaching toxicity test, the stabilization rates of arsenic in soil samples S1, S2, and S3 were 97.98%, 99.61%, and 99.22%, respectively, and the arsenic content in the leaching solution was 2.32mg / L and 1.48mg / L and 3.43mg / L are both lower than 5mg / L.

[0069] Table 1 Some characteristics of artificially configured simulated soil samples

[0070]

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Abstract

The invention discloses a method for remedying arsenic polluted soil. The method comprises a step of adding iron salt solution into the arsenic polluted soil so that the iron salt solution is reacted with arsenic in the soil to form arsenate FeAsO3 or FeAsO4 of iron. Before the iron salt solution is added, the method also comprises a step of crushing the arsenic polluted soil and steps of adjusting the pH of the arsenic polluted soil and measuring the arsenic content of the arsenic polluted soil. The method can quickly and efficiently treat the arsenic polluted soil, has simple operation and management and is suitable for major unexpected arsenic pollution remediation.

Description

Technical field [0001] The invention relates to a method for treating arsenic-contaminated soil in situ. Background technique [0002] Arsenic is a kind of heavy metal. Its abundance in the earth's crust is 1.8mg / kg, and its element abundance ranks 20th. It is an element widely distributed in nature. Its compounds are obtained in the production of alloys, dyes, pesticides, preservatives, etc. widely used. With the development of the arsenic industry, major environmental pollution accidents caused by the leakage of arsenic-containing chemicals, fires, and explosions have also occurred from time to time. For example, on December 11, 2002, an arsenic transport vehicle overturned in Qijian Township, Jinxiu County, Guangxi, and 20 tons of arsenic leaked, causing large-scale pollution of hillsides and water bodies along the way. In 2008, a chemical plant in the upper reaches of the Dasha River in Minquan County, Henan Province, replaced pyrite with high arsenic content of arsenic pyr...

Claims

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Application Information

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IPC IPC(8): B09C1/08
Inventor 张焕祯赵慧敏赵茜张莹李飞庞博唐敏陈宗英
Owner CHINA UNIV OF GEOSCIENCES (BEIJING)
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