Chemical fixing agent for heavy metal contaminated soil remediation and preparation and application thereof

A contaminated soil and chemical immobilization technology, which is applied in the restoration of polluted soil, chemical instruments and methods, and compositions for inhibiting chemical changes, can solve the problems of low heavy metal immobilization efficiency, easy re-release of heavy metals, and secondary pollution. Achieve the effect of low cost, wide source of raw materials, and strengthening the fixing effect

Active Publication Date: 2013-09-04
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The commonly used chemical fixatives have the following problems: (1) The fixation efficiency of natural mineral fixatives for heavy metals is low (usually within 30%); (2) When organic fixatives are used for heavy metal contaminated soil remediation, Secondary pollution; (3) Lime-based fixatives usually change the pH of the soil to make heavy metals form hydroxides and carbonates. Once the environmental conditions change, heavy metals are easy to re-release, especially in areas with severe acid rain. occur

Method used

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  • Chemical fixing agent for heavy metal contaminated soil remediation and preparation and application thereof
  • Chemical fixing agent for heavy metal contaminated soil remediation and preparation and application thereof
  • Chemical fixing agent for heavy metal contaminated soil remediation and preparation and application thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Dissolve titanium dioxide waste slag in water, and measure its Fe by titration 2+ content, and formulated to 0.3mol L -1 FeSO 4 solution, add Ca(H 2 PO 4 ) 2 powder, stir until completely dissolved; add carbide slag supernatant to the above mixed solution while stirring, adjust the pH of the mixed solution to 7.02; then add the molar ratio of H 2 o 2 : Fe 2+ =1.2:1 Add hydrogen peroxide, react for 90 minutes, vacuum filter, and dry the resulting filter residue in a constant temperature oven at 60°C to constant weight, crush it and pass it through a 20-mesh sieve to prepare a soil heavy metal fixative. Weigh 100g of lead and cadmium contaminated soil, add 5g of the above-mentioned fixative, add tap water according to the soil-water mass ratio of 3:1, and stir until uniform. Samples were taken at 1, 2, 5, 7, and 14 days respectively, and the available Cd, Pb, and Zn contents in the soil (DTPA extraction dosage state) were determined. After testing, the soil availa...

Embodiment 2

[0030] Dissolve titanium dioxide waste slag in water, and measure its Fe by titration 2+ content, and formulated to 0.3mol L -1 FeSO 4 solution, add phosphoric acid to the above solution at a molar ratio of P / Fe=0.08, and stir until completely dissolved; add carbide slag supernatant to the above mixture while stirring, and adjust the pH of the mixture to 8.45; Molby H 2 o 2 : Fe 2+ =1.5:1 Add hydrogen peroxide, oxidize for 120 minutes, vacuum filter, and dry the resulting filter residue in a constant temperature oven at 70°C to constant weight, crush it and pass it through a 20-mesh sieve to prepare a soil heavy metal fixative.

[0031] Weigh 100g of lead and cadmium contaminated soil, add 5g of the above-mentioned fixative, add tap water according to the soil-water mass ratio of 3:1, and stir until uniform. Samples were taken at 1, 2, 5, 7, and 14 days respectively, and the available Cd, Pb, and Zn contents in the soil (DTPA extraction dosage state) were determined. Aft...

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Abstract

The invention provides a chemical fixing agent for heavy metal contaminated soil remediation and a preparation and an application thereof. the preparation method comprises the following steps: 1) using titanium dioxide waste residue as a raw material, stirring while adding phosphate and an alkaline substance into a solution successively, and adjusting pH to alkaline; and 2) adding an oxidizing agent into a mixed liquor, fully stirring, reacting for 60-120min, filtering, drying the residue at 50-80 DEG C, grinding and sieving through a 20-mesh sieve so as to obtain a heavy metal fixing agent. The heavy metal fixing agent is added into lead-cadmium contaminated soil according to the mass ratio of 5%. Effective state cadmium and lead fixed rates reach 34-43% and 41-48% respectively. According to the heavy metal fixing agent provided by the invention, industrial solid wastes are fully utilized, and the preparation process is simple and requires low cost. In addition, the fixing agent prepared by the preparation method has a good effect of fixing heavy metal and can be used for lead-cadmium contaminated soil remediation.

Description

technical field [0001] The invention relates to a chemical fixative product for repairing heavy metal polluted soil, a preparation method and its application in repairing heavy metal polluted soil. Background technique [0002] Soil is the natural environment on which human beings depend and an important resource for agricultural production. However, environmental pollution and ecological damage are becoming more and more serious, seriously affecting human health and survival, among which heavy metal elements have a particularly serious effect on environmental pollution and damage. Soil heavy metal pollution and its restoration have become the focus of current environmental science research. [0003] At present, the remediation of heavy metal-contaminated soil mainly includes physical, chemical, and biological methods. Physical remediation is mainly the foreign soil method, which is suitable for small areas of seriously polluted soil, but the replaced soil must be treated. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K15/02B09C1/08
Inventor 杨志辉柴立元吴瑞萍吴宝麟闵小波杨卫春廖映平
Owner CENT SOUTH UNIV
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