Method for restoring heavy-metal-polluted soil through plants

Abstract

The invention relates to a method for restoring heavy-metal-polluted soil through plants. The method comprises the following steps that (1), to-be-restored heavy-metal-polluted soil is selected, then slaked lime is laid and sprinkled into the soil, and the soil and the slaked lime are evenly mixed; (2), after a week, pennisetum begins to be planted in the to-be-restored heavy-metal-polluted soil, after growing for 120 days, the pennisetum can be harvested, the harvested pennisetum is processed into biomass granular fuel, the planted pennisetum is harvested twice a year, after harvesting of the second time, pennisetum root tips are turned out for airing, and after being aired, the pennisetum root tips are processed into the biomass granular fuel; and (3), pennisetum is planted again in the next year, and the step (2) is repeated again for continuing treating and restoring till the soil is detected to accord with the standard within the state-specified allowable value. The method for restoring the heavy-metal-polluted soil through the plants has the advantages of being low in restoring cost and capable of avoiding secondary pollution, and the method is suitable for application of restoring of the large-area heavy-metal-polluted soil.

Description

technical field [0001] The invention relates to a method for repairing heavy metal polluted soil, in particular to a method for phytoremediation of heavy metal polluted soil. Background technique [0002] Rice is the staple food of more than 60% of the Chinese people, and now the heavy metal pollution of rice has surfaced day by day. According to a sample survey reported by the "New Century" weekly, about 10% of the rice in many markets in China contains excessive cadmium content. Cadmium is a heavy metal. Long-term accumulation will cause harm to human bones and kidneys. Cadmium pollution has certain concealment but can cause chronic poisoning and cancer. The emergence of the "Cadmium Rice Crisis" once again sounded the alarm of soil pollution. [0003] Soil heavy metal pollution refers to that the content of trace metal elements in soil exceeds the background value due to human activities, and the content is too high due to excessive deposition, which is collectively ref...

AI Technical Summary

Problems solved by technology

The original treatment methods such as mechanical separation, chemical rinsing, electric restoration, etc. have high restoration costs, complicated operations, and even the threat of secondary pollution. Therefore, the above methods are not suitable for the restoration of large-scale heavy metal-contaminated soil. application