Remediation method for heavy metal cadmium-contaminated farmland

Abstract

The invention provides a remediation method for heavy metal cadmium-contaminated farmland. The method comprises the steps as follows: water is added to the farmland, so that the farmland is soaked inthe water; a ferric salt solution is added to the treated heavy metal-contaminated farmland, and the farmland is ploughed, broken and then flattened; the surface of soil is covered with a fiber film;and the steps are repeated as a cycle. The distance between the soaking water surface and the surface of the farmland during still standing ranges from 0.5 cm to 1.5 cm, the farmland is ploughed and broken for 1-3 times, the concentration of the ferric salt solution is 0.5-1.5 mg/L, ferric salt is ferric chloride or ferric sulfate, the fiber film is a polypropylene fiber film containing activatedcarbon, modified diatomite and modified kaolin, the fiber film covering time ranges from 3 days to 5 days, and the circulating times ranges from 3 times to 5 times. The remediation method has the obvious treatment effect, the content of cadmium in the heavy metal-contaminated farmland can be effectively reduced, used reagents and materials such as the ferric chloride, the polypropylene fiber filmand the like are low in price and easy to obtain, the treatment cost is reduced, the treatment efficiency is high, and the farmland remediation speed is high.

Description

technical field [0001] The invention belongs to the technical field of cultivated land pollution control, and in particular relates to a repair method for cultivated land polluted by heavy metal cadmium. Background technique [0002] Soil heavy metal pollution refers to human activities, the content of trace metal elements in the soil exceeds the background value, and the excessive content caused by excessive deposition is collectively referred to as soil heavy metal pollution. Heavy metals refer to metals with a specific gravity equal to or greater than 5.0, mainly including elements with significant biological toxicity such as cadmium, mercury, lead, chromium, and metalloid arsenic, as well as elements with certain toxicity such as zinc, copper, and nickel. These polluting elements mainly come from pesticides, wastewater, sludge and atmospheric deposition, etc. For example, cadmium and lead pollution mainly come from smelting emissions and vehicle exhaust gas deposition, m...

AI Technical Summary

Problems solved by technology

Although this method can restore cadmium-contaminated cultivated land soil, the chemicals added to the cultivated land are likely to cause secondary pollution, and the heavy metal precipitates after flocculation and sedimentation will be mixed in the soil, making it difficult to separate them.

[0005] In summary, there is currently no fast, low-cost, and efficient way to remediate heavy metal cadmium-contaminated cultivated land.