Device and method for restoring soil polluted by polychlorinated biphenyl

A technology for polluted soil and polychlorinated biphenyls, which is applied in the restoration of polluted soil and other directions, can solve the problems of PCBs pollution, short chemical repair cycle, unfavorable industrial promotion, etc., and achieves easy automatic control and small equipment footprint. , a wide range of effects

Active Publication Date: 2013-09-25
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Among them, physical remediation cannot fundamentally solve the pollution problem of PCBs in the environment, but is only a temporary measure based on the different functions of the land; chemical remediation has a short period and obvious effect, but it requires high cost and is easy to cause secondary pollution. At present, the understanding of some reaction mechanisms is still unclear, and some methods are not cond

Method used

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  • Device and method for restoring soil polluted by polychlorinated biphenyl

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] The electrolysis of soil pollutants is carried out in the electrolytic cell. Take 150g of hexachlorobenzene-contaminated kaolin, the content of hexachlorobenzene is 500mg / kg, and the moisture content is 45%, and put it into the reaction device. Insert the electrode anode and the electrode cathode at both ends of the polluted soil respectively. The anode is a square stainless steel wire mesh, and the cathode is made of graphite felt. The size of the plates is 6cm×4cm×0.2cm. Deionized water is used as the electrolyte solution. The voltage gradient was 1.0 V / cm, and the electrode spacing was 20 cm. The amount of air blown into the soil is controlled by an air pump near the cathode of the electrolyzer. β-cyclodextrin with a concentration of 0.5mol / L was selected as co-solvent and added to the anode chamber. Ultrasonic emission adopts a device with a probe, the ultrasonic frequency is 20kHz, the output power is 100W, and the irradiation time is 30min. This experiment was d...

Embodiment 2

[0050] This experiment was carried out in a single-chamber device with a size of 20cm×14cm×8cm and a material of HDPE. 500g of old soil artificially doped with a concentration of 100mg / kg hexachlorobiphenyl (HCB) was piled into the device as an experimental sample. The soil pH was 3.0 and the moisture content was 60%. The surface area of ​​both electrodes was 32.97cm 2 Graphite electrode, insert the negative and positive electrodes into the soil, the distance between the two electrodes is 15cm; choose sodium sulfate as the electrolyte solution; put H 2 o 2 The solution is added to the anode; β-cyclodextrin co-solvent with a concentration of 0.5mol / L is added to the injection well; the ultrasonic emission adopts a device with a probe, the ultrasonic frequency is 20kHz, the output power is 400W, and the irradiation time is 1~ 4h. Due to the high content of iron minerals inherent in kaolin, which can catalyze the electro-Fenton reaction of hydrogen peroxide, no iron-containing ...

Embodiment 3

[0052] In Example 1, other conditions remain unchanged, when the frequency of the ultrasonic wave is increased to 50kHz, and H 2 o 2 When the solution concentration was 30%, the removal rate of HCB in soil was 69.3%; when the ultrasonic frequency was increased to 100kHz, and H 2 o 2 When the solution concentration was 30%, the removal rate of HCB in soil was 76.9%. It can be seen that increasing the ultrasonic frequency is beneficial to the removal of HCB in soil.

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Abstract

The invention belongs to the technical field of environment protection, and in particular relates to a device and a method for restoring soil polluted by polychlorinated biphenyl. Oxygen fed into the soil is reduced on the surface of a cathode to produce hydrogen peroxide by applying a power supply; ferrous ions in the soil and the hydrogen peroxide perform reaction to generate hydroxyl radical (.OH); the.OH can oxidize and degrade organic pollutants in the soil, so that the organic pollutants can be finally converted into small-molecule substances such as CO2, H2O and inorganic salt. By a union ultrasonic technology, the pollutants in the soil can be physically desorbed according to a mechanical effect and an emptying phenomenon, and water molecules can be decomposed to form free radicals with high oxidability such as the.OH; an effect of promoting electro-fenton is achieved. The device and the method have wide application range and short treatment period; the soil polluted by the polychlorinated biphenyl can be economically and effectively subjected to in-situ restoration.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and particularly relates to a device and method for repairing soil polluted by polychlorinated biphenyls. Background technique [0002] According to WHO statistics, since the production began in the 1920s to the end of the 1980s, the world produced about 2x10 7 t of industrial PCBs, about 31% of which have been discharged into the environment. Due to the stable physical and chemical properties of polychlorinated biphenyls (PCBs), they have the characteristics of persistence, resistance to biodegradation, fat solubility, semi-volatility, long-distance migration and obvious biological toxicity, which pose a great threat to organisms and human health. , causing global pollution, is one of the first 12 POPs to be eliminated according to the Stockholm Convention on Persistent Organic Substances (POPs Convention for short). Studies have shown that the toxicity of PCBs is mainly manif...

Claims

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Application Information

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IPC IPC(8): B09C1/08
Inventor 卢宏玮任丽霞何理
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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