A stabilizer for heavy metal compound polluted soil and preparation method thereof

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 contaminated soil and a preparation method thereof, in particular to a stabilizer for heavy metal compound contaminated soil and a preparation method thereof. Background technique [0002] The heavy metal pollution has become one of the biggest environmental problems of soil pollution because of the great harm, the deep degree and the wide area. In recent years, frequent heavy metal environmental pollution incidents have caused the public to pay more and more attention to this problem. Unlike organic pollution, heavy metals are non-biodegradable. Once they enter the soil, they will exist, accumulate and migrate in different chemical forms. Some of the heavy metals in the soil will migrate to surface water or groundwater with the water cycle, or through different channels. Enter the food chain, and accumulate and enlarge in different trophic levels, so it may...

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

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