Chemical-thermal desorption combined remediation method for polycyclic aromatic hydrocarbon contaminated soil

A technology for contaminated soil and polycyclic aromatic hydrocarbons, applied in the field of soil pollution remediation, can solve problems such as unsuitable for large-scale remediation applications, PAHs are not easy to volatilize, and ozone soil is difficult to aerate, so as to improve remediation cost-effectiveness, good remediation effect, and increase ecotoxicity Effect

Inactive Publication Date: 2021-12-03
SOUTHEAST UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its main disadvantages are: since most PAHs are not volatile and difficult to biodegrade, this method has low repair efficiency, high cost, and is not suitable for large-scale repair applications.
Its main disadvantages are: it has high requirements on the environment, and it is not suitable for dealing with large-scale and complex contaminated soil; and the repair period of this technology is relatively long, and the repair efficiency is low
The problem that these oxidizing agents exist in use is: Na 2 S 2 o 8 The reaction rate is low at room temperature, and the oxidation effect is not significant. It needs to be activated by heat activation, alkali activation, ultraviolet activation, etc., which increases the repair cost.
However, hydrogen peroxide has the problem of rapid decomposition, and ozone has the problem of difficult soil aeration.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] A chemical-thermal desorption combined remediation method for polycyclic aromatic hydrocarbon contaminated soil, comprising the following steps,

[0029] Step 1. Pretreatment of contaminated soil: The soil contaminated by polycyclic aromatic hydrocarbons is crushed, ground, and sieved with a 1-2mm sieve in sequence, and the moisture content of the soil is adjusted to 16%. The soil sample is obtained for later use;

[0030] Step 2, chemical pre-oxidation treatment: add 2wt% oxidant to the soil sample by dry mixing method, and carry out chemical pre-oxidation treatment under agitation for 24 hours; the oxidant is benzoyl peroxide; The stirring is carried out in an overturning oscillator, and the stirring speed is 30rpm;

[0031] Step 3. Thermal desorption: heat the pre-oxidized soil at 100° C. for 30 minutes, and then cool it to room temperature.

Embodiment 2

[0033] A chemical-thermal desorption combined remediation method for polycyclic aromatic hydrocarbon contaminated soil, comprising the following steps,

[0034] Step 1. Pretreatment of contaminated soil: The soil contaminated by polycyclic aromatic hydrocarbons is crushed, ground, and sieved with a 1-2mm sieve in sequence, and the moisture content of the soil is adjusted to 16%. The soil sample is obtained for later use;

[0035] Step 2, chemical pre-oxidation treatment: add 5wt% oxidant to the soil sample by dry mixing method, carry out chemical pre-oxidation treatment under agitation, and the treatment time is 24h; the oxidant is benzoyl peroxide; The stirring is carried out in an overturning oscillator, and the stirring speed is 30rpm;

[0036] Step 3. Thermal desorption: heat the pre-oxidized soil at 100° C. for 30 minutes, and then cool it to room temperature.

Embodiment 3

[0038] A chemical-thermal desorption combined remediation method for polycyclic aromatic hydrocarbon contaminated soil, comprising the following steps,

[0039] Step 1. Pretreatment of contaminated soil: The soil contaminated by polycyclic aromatic hydrocarbons is crushed, ground, and sieved with a 1-2mm sieve in sequence, and the moisture content of the soil is adjusted to 16%. The soil sample is obtained for later use;

[0040] Step 2, chemical pre-oxidation treatment: add 2wt% oxidant to the soil sample by dry mixing method, and carry out chemical pre-oxidation treatment under agitation for 24 hours; the oxidant is benzoyl peroxide; The stirring is carried out in an overturning oscillator, and the stirring speed is 30rpm;

[0041] Step 3. Thermal desorption: heat the pre-oxidized soil at 200° C. for 30 minutes, and then cool it to room temperature.

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PUM

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Abstract

The invention relates to a chemical-thermal desorption combined remediation method for polycyclic aromatic hydrocarbon contaminated soil. The method comprises the following steps: 1, pretreatment of the contaminated soil: sequentially crushing, grinding and screening the polycyclic aromatic hydrocarbon contaminated soil, and then adjusting the moisture content of the soil to obtain a soil sample for later use; 2, chemical pre-oxidation treatment: adding an oxidizing agent into the soil sample by adopting a dry mixing method to carry out chemical pre-oxidation treatment; and 3, thermal desorption: performing thermal desorption treatment on the soil subjected to pre-oxidation treatment under a medium-temperature condition, and then cooling to room temperature. According to the method, the contaminated soil is pre-oxidized through the oxidizing agent containing benzoyl peroxide, then the PAHs contaminated soil is subjected to thermal desorption treatment, the PAHs removal efficiency can be improved, meanwhile, the remediation temperature can be reduced, and therefore the purposes of reducing remediation energy consumption and remediation cost are achieved.

Description

technical field [0001] The invention belongs to the technical field of soil pollution remediation, and in particular relates to a chemical-thermal desorption combined remediation method for polycyclic aromatic hydrocarbon contaminated soil. Background technique [0002] Polycyclic aromatic hydrocarbons (PAHs) are a class of uncharged, nonpolar, and lipophilic polycyclic carbon organic compounds, usually containing two or more benzene rings connected in the form of fused rings, straight chains, or angles. The degradation of PAHs under natural conditions is very difficult. PAHs are easily adsorbed in soil or sediment particles rich in organic matter, and have "three effects" and biological toxicity. The polluted soil seriously threatens human life and health and the safety of the ecological environment. [0003] PAHs pollution widely exists in waters, atmosphere and soil around the world, among which soil pollution is the most serious. In the past 30 years, due to my country...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/08B09C1/06
CPCB09C1/08B09C1/06
Inventor 张亚平徐成华刘刚于天施威陈春红
Owner SOUTHEAST UNIV
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