Hexavalent chromium contaminated soil in-situ remediation method

Abstract

The invention discloses a hexavalent chromium contaminated soil in-situ remediation method. The method comprises the following steps: dissolving a water-soluble sulfur-containing reagent into water, preparing 0.1-10 percent of a reducing agent, mixing chromium contaminated soil and the reducing agent in a reactor according to a mass ratio of the soil to the reducing agent being 3:1-1:5, stirring for 0.5-2 hours, and drying. Then, a stabilizer is added for treatment, so that the soil meets the environmental risk control requirement. The hexavalent chromium which is high in toxicity and easy to migrate and can be absorbed and utilized by plants in the soil is completely reduced and immobilized into trivalent chromium which is low in toxicity and difficult to migrate and can be utilized by plants, and bounce is difficultly caused. The in-situ remediation of the heavy metal hexavalent chromium contaminated soil is realized.

Description

technical field [0001] The invention relates to an in-situ remediation technology for hexavalent chromium-contaminated soil. Specifically, by configuring a water-soluble sulfur-containing reagent as a reducing agent and a water-soluble phosphorus-containing reagent as a stabilizer, the highly toxic soil that can be The hexavalent chromium absorbed and utilized by plants is reduced and fixed, and the in-situ remediation of hexavalent chromium-contaminated soil is realized. Background technique [0002] my country's soil is seriously polluted by heavy metals. The "National Soil Pollution Survey Bulletin" shows that the national chromium pollution rate is 1.1%, which is one of the eight major polluting heavy metals. There are many sources of chromium in soil, among which the most serious hazards mainly contain three aspects: 1) Random dumping of industrial waste and municipal waste. According to reports, in the past 30 years of reform and opening up, my country has accumulate...

AI Technical Summary

Problems solved by technology

According to reports, in the past 30 years of reform and opening up, my country has accumulated 6 million tons of chromium slag due to metallurgical and chemical production, and the annual output has increased by 200,000 to 300,000 tons. Many factories lack good chromium slag treatment facilities and pile up everywhere, resulting in Hexavalent chromium leaching from chromium-containing waste and further polluting the surrounding soil

2) Sewage irrigation and sludge use, sewage irrigation leads to excessive chromium concentration in rice fields in many sewage irrigation areas

3) Irrational application of chromium-containing fertilizers and pesticides in agricultural farming is also the main cause of soil hexavalent chromium pollution

The pH and other conditions required to remove hexavalent chromium and trivalent chromium are opposite, and it is difficult to achieve the purpose of simultaneous removal

In addition, the technology is currently only being explored in the laboratory

Because the current action distance is too small, and the actual polluted land area is too large, this technology is difficult to implement in engineering, and despite its high operating costs, it is unaffordable