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A method for removing heavy metals from polluted soil by using magnetically modified biochar

A technology of polluted soil and biochar, applied in the field of polluted soil remediation, can solve the problems of low technical content of foreign soil, long remediation time, poor stability of remediation effect, etc. The effect of reducing engineering construction and investment

Inactive Publication Date: 2020-09-15
江西夏氏春秋环境股份有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Physical restoration includes foreign soil, solidification, electrodynamic restoration, etc. Among them, foreign soil has low technical content and a large amount of engineering, and only exchanges the spatial positions of non-polluted soil and polluted soil, without any restoration of polluted soil; solidification restoration is to remove heavy metal pollution The material and the soil are sealed together. Although the heavy metal pollution cannot be migrated, the soil also loses a variety of use values; the actual repair of electrodynamic repair is affected by the electrode material, and the repair effect is poor in stability, which is not suitable for engineering applications.
[0004] Chemical remediation includes leaching, chemical redox, chemical stabilization, etc. Among them, leaching technology is currently the most used heavy metal pollution remediation method at home and abroad, mainly because it completely reduces the content of heavy metal pollutants in the soil, but it will produce a large amount of leaching. Washing waste liquid needs to be treated, and the amount of engineering is increased; chemical redox is only for the restoration of volatile heavy metals, and has little effect on the restoration of a large number of other heavy metals; after the stabilization restoration stabilizes the effective state of heavy metals, the migration of heavy metal pollutants is reduced, but The stability effect cannot be guaranteed with the passage of time and environmental changes. It requires a lot of monitoring in the later stage, and there is a risk of being activated. At the same time, it is easy to produce secondary pollution, and the market is gradually shrinking.
[0005] Bioremediation uses plants, microorganisms, animals, etc. to stabilize and extract heavy metal pollutants. Although this method is green and economical, it has a long repair time and is difficult to adapt to the treatment of heavily heavy metal-contaminated soil, and the bioremediation rate is much lower than the pollution rate. There are many limitations

Method used

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  • A method for removing heavy metals from polluted soil by using magnetically modified biochar

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Experimental program
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Effect test

Embodiment 1

[0028] Around 100nm of Fe 3 o 4 Add 50g of granules and 10g of sodium lauryl sulfate into water, keep the solid-liquid mass ratio at 1:3, then add NaOH to adjust the pH to 10, raise the temperature to 95°C, stir for 1 hour, add concentrated nitric acid after the reaction to adjust the pH to 7, rinse with water And isolate the iron ferric oxide particles coated with sodium lauryl sulfate, then add it and sodium dodecylbenzenesulfonate to water with a mass ratio of 4: 1, keep the solid-liquid mass ratio of 1: 3, and heat up Keep at 60°C for 1 hour to prepare a magnetic agent coated with two layers of surfactants; modify and activate biochar and 0.2 mol / L manganese chloride solution at a solid-liquid mass ratio of 1:2 at a pH of 5 for 2 hours , and then wash the pH to 7 with clean water to obtain modified biochar; then add the modified biochar and magnetic agent to water at a mass ratio of 1:1, keep the solid-liquid mass ratio at 1:5, heat up to 60°C and stir for 1 hour , and t...

Embodiment 2

[0030] The polluted soil is located in agricultural land near a watershed. The polluted area is 34 mu. The pH of the soil is between 6.5 and 7.5. The heavy metal pollution is: cadmium 5mg / kg, arsenic 150mg / kg, lead 1000mg / kg. The contaminated soil is transported to the vicinity of the site for purification and disposal. When feeding, the contaminated soil and magnetically modified biochar are mixed with a mass ratio of 500:1 and added to the flushing and screening system. The modified biochar enters the strong stirring mixing system with a mass ratio of 200:1, and the solid-liquid mass ratio is 1:5. The contaminated soil and magnetically modified biochar are stirred and mixed in the mixing system for 1 hour, and then enter the magnetic separation system; Wet permanent magnetic separation is adopted with a magnetic field strength of 300-400mT. After the magnetically modified biochar is separated by magnetic separation, the residue enters the solid-liquid separation system; after...

Embodiment 3

[0032]The polluted soil is located in a site left by the relocation of an industrial plant. The polluted area is 78 mu. The soil pH is between 6.5 and 7.5. The heavy metal pollution is: cadmium 180mg / kg, lead 3000mg / kg, copper 20000mg / kg, nickel 2800mg / kg. Contaminated soil is transported to the vicinity of the site for purification and disposal. When feeding, polluted soil and magnetically modified biochar are mixed into the flushing and screening system at a mass ratio of 40:1; after screening, soil components with a particle size of less than 5mm and magnetically modified biochar are mixed at a mass ratio of 20:1 Then enter the strong stirring mixing system, the solid-liquid mass ratio is 1:5, the contaminated soil and magnetically modified biochar are stirred and mixed in the stirring mixing system for 2 hours, and then enter the magnetic separation system, using wet permanent magnet magnetic separation, the magnetic field strength 300-400mT; After magnetic separation and ...

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Abstract

The invention discloses a method for removing contaminated-soil heavy mental with magnetic-modified biochar. The method includes the specific steps that the prepared magnetic-modified biochar serves as a soil remediation agent, water serves as a dispersion medium, heavy metal contaminated soil and the magnetic-modified biochar are mixed and make contact with each other, the steps such as high pressure washing sieving, continuous strong mixing, magnetic separating and solid-liquid separating are carried out, and standard soil for agricultural production and construction is obtained. According to the method, the magnetic-modified biochar is applied to heavy metal contaminated soil remediation, the treatment process of leaching waste liquid is fundamentally eliminated, engineering construction and cost are reduced, heavy metal contaminants in soil are thoroughly removed, and the environmental risk is eliminated. Meanwhile, a large amount agricultural waste can be consumed through resourceutilization of the biochar, and contamination caused by waste incineration and landfill and land occupancy are reduced.

Description

technical field [0001] The invention relates to a method for removing heavy metals from polluted soil by using magnetically modified biochar, and specifically belongs to the technical field of polluted soil remediation. Background technique [0002] With the continuous acceleration of the industrialization process, soil heavy metal pollution is becoming more and more serious, which has a serious impact on the soil ecosystem, and at the same time enters the human body through the food chain, causing harm to human health. At present, the remediation technologies for soil heavy metal pollution mainly include physical remediation, chemical remediation, and biological remediation. [0003] Physical restoration includes foreign soil, solidification, electrodynamic restoration, etc. Among them, foreign soil has low technical content and a large amount of engineering, and only exchanges the spatial positions of non-polluted soil and polluted soil, without any restoration of polluted...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B09C1/00B09C1/02
CPCB09C1/00B09C1/02
Inventor 王江帆孙燕张燕
Owner 江西夏氏春秋环境股份有限公司
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