Method for extracting heavy metal in soil using cotton

Abstract

The invention discloses a method for utilizing algondon to extract heavy metals from soil. The method comprises the steps that: a pollution source providing heavy metals is isolated from the land area where restoration is required and the heavy metal content of the soil is out of limits; the pH value of the soil in the land area is regulated and controlled to range from 6 to 7.5 and the algondon is selected as extraction plant, which is then planted in the soil of the land area; the planted algondon extracts the heavy metals in the soil of the land area and the algondon is planted and harvested for cotton in one phase or a plurality of phases without interruption till tests indicate that the content of the heavy metals in the soil meet the safety standards. The method is simple, highly operable and easy to populate as well as has low cost; furthermore, the obtained various parts of the algondon plant crops all can be used and have great economic and social benefits. The method can fundamentally eliminate harms the heavy metals do to soil health, foods safety and the health of human beings and effectively avoid secondary pollution without damaging the ecological environment of the soil.

Description

technical field [0001] The invention relates to a technology for controlling environmental pollution, in particular to a method for extracting heavy metals Zn, Cu and Cr in soil by using cotton (Gossypium hirsutum Linn.). Background technique [0002] In view of the prevalence and severity of soil heavy metal pollution, some developed countries have formulated corresponding soil remediation plans. The U.S. federal government has formulated a soil and groundwater remediation plan, and plans to invest tens of billions to hundreds of billions of dollars. In 1994, the United States initiated and established the "Global Soil Remediation Network (Global Soil Remediation Network)". [0003] The traditional treatment of heavy metal-contaminated soil mainly adopts physical or chemical methods such as soil solidification, vitrification, leaching, soil washing, guest soil, and electrochemical methods. These methods have the following disadvantages: (1) the cost is high, and one hecta...

AI Technical Summary

Problems solved by technology

These methods have the following disadvantages: (1) the cost is high, and one hectare of heavy metal-contaminated land is often as high as tens of millions of dollars, and it is difficult to use on a large scale; (2) the soil ecological environment is destroyed, resulting in loss of soil structure, soil biological activity and The degradation of soil fertility often requires secondary treatment; (3) secondary pollution, the process of using physical and chemical methods to restore heavy metal-contaminated soil often results in re-pollution of the soil

[0005] The inventors found that from the current domestic and foreign plant extraction technology research and practical progress, there are still the following problems: (1) There are few plant varieties that can be selected to enrich heavy metals Zn, Cu and Cr, especially those that can enrich heavy metals at the same time There are very few plants with more than two kinds of metals; (2) hyperaccumulators, which are recommended for priority use, generally have low biomass, low overall removal efficiency of heavy metals, and there are also climate adaptation in different places and lack of economic benefits. (3) The bioavailability of heavy metals in contaminated soil needs to be improved; (4) From the perspective of application, some phytoremediation technologies in developed countries have been put into practical application and have achieved good environmental, economic and social benefits , while our country is still in its infancy, and the relevant technologies are still in the laboratory or pilot stage, lack of promotion and universality, and there is no method for using non-edible economic crop cotton to simultaneously and continuously extract multiple heavy metals exceeding the standard in soil