The previous section introduced several methods of phytochemical remediation of soil lead contamination, now we will introduce the remaining methods.

5, electrochemical method

Electrochemical method is to insert the electrode pair in the lead contaminated soil, through the DC, lead charged particles in the electromigration, electroporation and electrophoresis, etc. under the action of redox reaction, and migration, enrichment in the anus / anode, thus removing Contaminated soil lead. This technology is applied not only to lead contaminated soil in Europe, but also to remediation of heavy metal contaminated soils such as copper, zinc, chromium, nickel and cadmium. The technology is easy to operate, easy to install and technically feasible. It can remove contaminated soil containing 100mg / kg lead to 5 ~ 10mg / kg, and the treatment cost of contaminated soil is about 100 $ / m3. However, the electrode is susceptible to corrosion and there is a risk of secondary contamination. In addition, the complex conditions of the soil are also the limiting factors for this technology.

6, redox method

Redox method is to add redox agents in heavy metal contaminated soil to change the valence state of heavy metal ions by chemical reaction so as to reduce the activity and toxicity of heavy metals in the soil. For lead contaminated soil, commonly used reductants are ferrous sulfate, sulfite, sodium thiosulfate, sodium bisulfite, sulfur dioxide and so on. Studies have shown that the application of superphosphate, calcium magnesium phosphate, hydrated manganese oxide, etc. can also promote the precipitation of lead and reduce the exchangeable soil lead. This method should be noted that the choice of reducing agent, if the choice of improper, easy to cause secondary pollution of soil.

7, chelator method

Chelating agents applied in lead-contaminated soils can increase the activity and bioavailability of lead, making it easy to flow and absorb, often in conjunction with phytoremediation methods. Chelating agents on the one hand, the activation of lead ions in the soil, on the other hand affect the plant's absorption and transfer of lead. Currently there are two types of chelating agents commonly used: one is a synthetic chelating agent, such as EDTA, DTPA, EGTA, CDTA, etc .; the other is a natural chelating agent, such as oxalic acid, tartaric acid, citric acid and so on. Artificial chelating agent activation ability, natural chelating agent is easy to decompose, will not form secondary pollution, but the activation ability is weak. Therefore, the use of artificial chelating agent to be considered when the activation of heavy metals after the proliferation of environmental risks.

8, antagonistic method

For lead-contaminated soils, some heavy metals or trace elements that are not harmful to the human body can be used to reduce the exchangeable state of lead in the soil and inhibit the absorption of lead by plants through antagonism. Studies have shown that appropriate amount of selenium on the growth and development of rice seedlings have a promoting effect, and has the role of antagonizing the injury of heavy metals lead.

Oil Pressure Switch

We can provide all kinds of Oil Pressure Switch with high quality and reasonable price. The Oil Pressure Switch sends information directly to the vehicle's computer system. Once the data sent indicates low pressure, the computer automatically turns off the engine to avoid damaging vital auto parts. The switch has a very important role in vehicle, so it is only right to keep it in tip-top shape all the time. A damaged switch must be replaced immediately to ensure superior engine performance.

Oil Pressure Switch,Lubrication System,Oil Pressure Sensor

NINGBO DGOFEN AUTO TRADE CO., LTD , https://www.dgofen.com