Method for repairing heavy metal-polluted soil or sludge with nano-zero-valent iron (nZVI)

A technology of nano-zero-valent iron and polluted soil, which is applied in the restoration of polluted soil, sludge treatment, chemical instruments and methods, etc., to achieve the effect of simple system structure, low energy consumption and low cost

Inactive Publication Date: 2012-03-21
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for repairing heavy metal-contaminated soil or sludge with nanometer zero-valent iron to separate heavy metals in soil / sludge, Eliminate the risk of future contamination

Method used

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  • Method for repairing heavy metal-polluted soil or sludge with nano-zero-valent iron (nZVI)
  • Method for repairing heavy metal-polluted soil or sludge with nano-zero-valent iron (nZVI)
  • Method for repairing heavy metal-polluted soil or sludge with nano-zero-valent iron (nZVI)

Examples

Experimental program
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Embodiment 1

[0032] The soil is collected at a depth of 10-100cm in a certain place. The content of heavy metals (zinc, lead, cobalt, nickel, copper) in the soil is between 3-100mg / Kg, and the pH value is between 6.8-7.5. In this study, several soil samples with the same heavy metal content were designed. For several samples with the same conditions, the amount of nZVI was increased sequentially, and the change of the removal rate of heavy metals in the soil was investigated with the increase of the amount of nZVI. In order to make the experimental effect more obvious, the heavy metal soil spiked method was adopted. The heavy metal spiked concentration was 500-1500mg / Kg, where the soil amount was 10-100g, the water volume was 100-1000 mL, and the nZVI amount was 2-50 g. According to the technological process of this study, the water and the spiked soil were mixed for 15-24 hours through the mixing reaction device, and the contents of heavy metals in the mixed liquid water and soil were resp...

Embodiment 2

[0034] The soil is collected at a depth of 10-100cm in a certain place. The local content of heavy metals (zinc, lead, cobalt, nickel, copper) in the soil is between 3-100mg / Kg, and the pH value is between 6.8-7.5. This study is designed as a soil sample with a specific heavy metal content (500-1500mg / Kg). The same amount of nZVI (2-20g) was added to the sample in batches, and nZVI was not added once. After the reaction is sufficient, the heavy metals will be adsorbed. The separation of nZVI was used to determine the removal rate of heavy metals in soil. In order to make the experimental effect more obvious, the method of adding heavy metals to the soil is adopted, and the concentration of heavy metals is 500-1500mg / Kg. Here, the amount of soil is 10-100g, and the volume of water is 100-1000 mL. According to the technological process of this study, the water and the spiked soil were mixed for 15-25 hours through the mixing reaction device, and the contents of heavy metals in t...

Embodiment 3

[0036] In contrast to the removal of heavy metals from soil or sludge by nanoscale zero-valent iron, the removal of heavy metals (zinc, lead, cobalt, nickel, copper) in pure water was studied. The volume of the aqueous solution is 100-1000mL, the concentration of heavy metals in the aqueous solution is 10-150mg / L, and the dosage of nZVI is 0.1-25g / L. Prepare aqueous solutions containing different concentrations of heavy metals, add different amounts of nZVI, mix thoroughly for 1-10 hours, and then introduce the reaction separation zone. In the reaction separation zone, water, nZVI and the electromagnet are in full contact, and the nZVI adsorbed with heavy metals is absorbed by the electromagnet. After separation, the separated water is directly subjected to ICP test after routine digestion, and the removal rate of heavy metals in water is calculated according to the concentration change of heavy metals in water before and after adding nZVI. The removal rate of 5 kinds of metal...

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Abstract

The invention relates to a method for repairing heavy metal-polluted soil or sludge with nano-zero-valent iron (nZVI). The method comprises the following steps of: fully mixing treated soil, sludge and the nZVI by using a nanotechnology, wherein a part of heavy metals in the soil or sludge is reduced by the nZVI, and the other part is adsorbed onto the surface of the nZVI, so that the heavy metals in the soil or sludge are removed; and separating the nZVI containing heavy metals by adopting a magnet, so that the change of the physicochemical property of the soil or sludge during or after the removing process is reduced. The method is easy to operate, has a remarkable effect, can be used for removing copper, nickel, zinc, cobalt, chromium, cadmium, lead and the like existing in the soil orsludge in one step, and has the characteristics of low cost, high repairing rate and the like when applied to the type of heavy-metal-polluted soil. In the invention, certain adjustment can be performed on parameters, such as nZVI concentration, treating time, liquid-solid rate and the like, according to different kinds and contents of heavy metals contained in different polluted soil or sludge. Purified soil or sludge gets back to farmlands, so that secondary pollution is not caused.

Description

technical field [0001] The present invention relates to the purification technology of soil or sludge polluted by heavy metals, in particular to a nanometer zero-valent iron repairing zinc (Zn), copper (Cu), lead (Pb), cadmium (Cd), chromium (Cr), Method for contaminating soil or sludge with heavy metals such as mercury (Hg). Background technique [0002] Soil is one of the main natural resources that human beings rely on for survival, and it is also an important part of the human ecological environment. According to the national survey of sewage irrigation areas conducted by the Ministry of Agriculture of my country, among the approximately 1.4 million hectares of sewage irrigation areas, the area of ​​land polluted by heavy metals accounts for 64.8% of the area of ​​sewage irrigation areas, of which 46.7% are lightly polluted and 9.7% are moderately polluted. %, serious pollution accounted for 8.4%. Soil heavy metal pollution has the characteristics of poor mobility of po...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/00C02F11/00
Inventor 张伟贤张亚雷
Owner TONGJI UNIV
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