Stabilizer for heavy metal compound contaminated soil and preparation method of stabilizer for heavy metal compound contaminated soil

A stabilizer and heavy metal technology, applied in the field of soil remediation, can solve the problems of inconspicuous stabilization effect, promotion of arsenic release, poor buffer capacity, etc., and achieve the effects of overcoming poor stabilization effect, realizing resource utilization, and reducing leaching concentration

Inactive Publication Date: 2015-03-25
CHINESE RES ACAD OF ENVIRONMENTAL SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] 1) Mostly, the effect on a single heavy metal is more significant, and the stabilization effect on the simultaneous presence of multiple heavy metal elements is not obvious, especially in the case of the simultaneous presence of lead, zinc, cadmium and arsenic
For example, many studies have shown that phosphate-containing materials have a significant effect on the stabilization of lead, but some studies have found that when phosphate is used in contaminated soil with high arsenic content, it will promote the release of arsenic;
[0006] 2) Traditional restoration materials mainly composed of lime, phosphate, etc. have a relatively single agent composition and poor buffering capacity. When the external conditions change, the stabilization effect is easily affected, and the long-term stability is questioned;
[0007] 3) In the existing heavy metal stabilizing agents, the addition of agents is mostly based on the mass ratio of the soil, ignoring that what the agent needs to stabilize is the bioavailable heavy metal part

Method used

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  • Stabilizer for heavy metal compound contaminated soil and preparation method of stabilizer for heavy metal compound contaminated soil
  • Stabilizer for heavy metal compound contaminated soil and preparation method of stabilizer for heavy metal compound contaminated soil
  • Stabilizer for heavy metal compound contaminated soil and preparation method of stabilizer for heavy metal compound contaminated soil

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] 1. Selection of contaminated soil

[0048] The soil samples were collected from a polluted site in Gansu. The basic properties of the soil are shown in Table 1. The leaching concentration of Pb in the soil sample was 40.37mg / L, and the leaching concentration of Zn was 229.39mg. / L, the leaching concentration of Cd is 8.56mg / L, and the leaching concentration of As is 0.03mg / L; the total effective state content of the heavy metals lead, zinc, and cadmium to be stabilized and the effective state content of arsenic are calculated.

[0049] Table 1

[0050]

[0051] 2. Selection of raw materials:

[0052] (1) Sodium sulfide: commonly known as soda sulfide, the chemical formula is Na 2 S·9H 2 O, content ≥ 98%, produced by Shanghai Tongya Chemical Technology Development Co., Ltd.;

[0053] (2) Shell powder: wash the shells with water, dry them, and grind them through a 400-mesh (38 μm) sieve. Mineral composition of shell flour see figure 1 ; Microscopic morphology and s...

Embodiment 2

[0063] The selection of polluted soil and raw materials is the same as in Example 1, and the preparation of the stabilizer is different from Example 1.

[0064] Sodium sulfide is added at a molar ratio of 3 times the total amount of heavy metal lead, zinc, and cadmium; shell powder is added at a molar ratio of 2 times the total amount of heavy metal lead, zinc, and cadmium; Add in a molar ratio of 4 times the effective state of arsenic.

[0065] The preparation method and use method of the stabilizer are the same as in Example 1, and the addition amount of the stabilizer is 5% of the soil weight. Seal and place the uniformly mixed sample in a standard curing box under the conditions of temperature 20±2°C and relative humidity 95%. After curing for 3 days, do toxicity leaching test. The test method is carried out according to the leaching method of the US Environmental Protection Agency TCLP, and the leaching results are as follows: Figure 5 shown.

[0066] From Figure 5...

Embodiment 3

[0068] The selection of polluted soil and raw materials is the same as in Example 1, and the preparation of the stabilizer is different from Examples 1 and 2.

[0069] Add sodium sulfide at a molar ratio of 6 times the total amount of available heavy metal lead, zinc, and cadmium; add shell powder at a molar ratio that is 4 times the total amount of available heavy metal lead, zinc, and cadmium; Add in a molar ratio of 8 times the effective state of iron to arsenic.

[0070] The preparation method and use method of the stabilizer are the same as in Example 1, and the addition amount of the stabilizer is 10% of the soil weight. Seal and place the uniformly mixed sample in a standard curing box under the conditions of temperature 20±2°C and relative humidity 95%. After curing for 3 days, do toxicity leaching test. The test method is carried out according to the leaching method of the US Environmental Protection Agency TCLP, and the leaching results are as follows: Figure 6 s...

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Abstract

The invention relates to a stabilizer for heavy metal compound contaminated soil and a preparation method of the stabilizer for heavy metal compound contaminated soil. The stabilizer comprises sulfide, shell powder and red mud, wherein the molar ratio of the sulfide to effective-state gross of heavy metals lead, zinc and cadmium is 1.5 to 6; the molar ratio of the shell powder to the effective-state gross of heavy metals lead, zinc and cadmium is 1-4; and the red mud is added in a molar ratio of the content of iron in the red mud to the effective-state content of arsenic in soil of 2-8. The preparation method of the stabilizer comprises the following steps: drying the red mud by airing, grinding and sieving the dried red mud; then, cleaning the shell powder, grinding and sieving after drying by air; and preparing the sulfide into an aqueous solution, thereby obtaining the stabilizer. Based on the effective-state content of the heavy metals in the soil, the content of each component is reasonably prepared, so that the stabilizer can be applicable to compound contaminated soil with high leaching concentration, can be used for effectively reducing the leaching concentration of heavy metals in the soil and overcoming the defect of poor stabilization effects of the existing medicament, and has a certain application value.

Description

technical field [0001] The invention relates to the technical field of soil remediation, in particular to a stabilizer for polluted soil and a preparation method thereof, in particular to a stabilizer for heavy metal compound polluted soil and a preparation method thereof. Background technique [0002] Heavy metal pollution is harmful, deep and wide, and has become one of the biggest environmental problems of soil pollution today. In recent years, frequent heavy metal environmental pollution incidents have made the public pay more and more attention to this issue. Different from organic pollution, heavy metals are non-biodegradable. Once they enter the soil, they will exist, accumulate and migrate in different chemical forms. Part of the heavy metals in the soil will migrate to surface water or groundwater with the water cycle, or through different channels. Entering the food chain, and accumulating and amplifying in different trophic levels, it may cause direct and indirec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K17/06
CPCB09C1/08C09K17/06
Inventor 张琢郭观林宋鑫莱王梅张朝李发生
Owner CHINESE RES ACAD OF ENVIRONMENTAL SCI
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