Cleaning method for repairing heavy metal contaminated soil

Abstract

The invention discloses a cleaning method for repairing heavy metal contaminated soil. The method is characterized by comprising the following steps: (1) adding water and an oxidant to heavy metal contaminated soil, wherein the oxidant is hydrogen peroxide; (2) adding an acid and a salt to the mixture obtained from the step (1), wherein the acid is any one or combination of hydrochloric acid and sulfuric acid; the salt is any one or combination of CaCl2 or FeCl3; and (3) carrying out solid-liquid separation on the mixture obtained from the step (2), adjusting the pH value of the obtained liquid to be 8-9, adding a flocculant, standing, participating and separating, wherein the flocculant is any one or combination of polyacrylamide and aluminum polychlorid. The repairing method disclosed by the invention has the advantages of being easily available in raw material, proper in cost, simple in preparation, good in repairing effect and the like; the combined adding ratio of medicines is determined according to the soil contamination degree and the physicochemical property, so that waste of the medicines caused by excessive repair is avoided; and the risk of secondary pollution is reduced.

Description

technical field [0001] The invention belongs to the field of environmental restoration engineering, and in particular relates to a cleaning method for repairing heavy metal polluted soil. Background technique [0002] With the advancement of the country's urbanization process and the development of industry and agriculture, the relocation of industrial enterprises has left a large number of heavy metal-contaminated sites, and agricultural sewage irrigation has caused heavy metal pollution in a large number of farmland soils, posing a huge threat to land circulation and reuse and food quality and safety. Heavy metal pollution Incidents occur frequently, and the phenomenon of compound polluted soil by various heavy metals is common, so people pay more attention to the restoration and treatment of compound polluted soil. [0003] Common methods for remediation of heavy metal-contaminated soil are as follows: [0004] 1. Soil replacement method and foreign soil method: the soil...

AI Technical Summary

Problems solved by technology

The disadvantages of these two technologies are: because the clean soil is expensive, it is only suitable for the restoration of contaminated soil with a small amount of engineering; farmland soil pays attention to the maintenance of its ecological function, and the soil replacement method and the guest soil method will destroy the soil structure and affect the production capacity of farmland soil.

The restoration cost of this method is low, and there is basically no secondary pollution in the restoration process, but the absorption of heavy metals by phytoremediation methods is limited, and it is not suitable for plant growth in high-concentration heavy metal-contaminated soil environments. There are also regional differences in screening and cultivation, and the phytoremediation cycle is long, making it difficult to meet engineering requirements

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