Hexavalent chromium-contaminated soil and groundwater remediation agent and preparation method

Abstract

The invention discloses a medicament for restoring hexavalent chromium contaminated soil and underground water. The restoring medicament consists of the following ingredients in percentage by mass: 35-45 percent of active carbon powder loaded acidified bentonite slurry, 35-45 percent of zero-valent iron powder loaded bentonite slurry and 10-30 percent of mixed slurry of bentonite and industrial waste alkali. The medicament is relatively high in hexavalent chromium reduction capability and can be used for effectively reducing the toxicity of the hexavalent chromium contaminated soil and underground water, efficiently reducing hexavalent chromium, curing trivalent chromium and also balancing the pH value of the soil and the underground water; meanwhile, the invention also provides a preparation method of the medicament, and thus the medicament can be used for treating wastes by using wastes and is low in cost and simple to prepare.

Description

technical field [0001] The invention belongs to the technical field of civil engineering and environmental geotechnical engineering, and specifically relates to a repairing agent for hexavalent chromium-contaminated soil and groundwater and a preparation method thereof, and the repairing agent can be used for greening and repairing hexavalent chromium-contaminated formations of land for construction In restoration projects, it is especially suitable for low-permeability hexavalent chromium-contaminated sticky and silty soils. Background technique [0002] Chromium and its compounds play an important role in modern industrial society. With the continuation of the industrialization process, a large number of modern industrial enterprises such as electroplating, tanning, metallurgy, and medicine have been built and developed. The three wastes discharged often contain a large amount of heavy metal chromium. Cause surrounding soil and groundwater pollution in the surrounding envi...

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Problems solved by technology

Among in-situ remediation technologies, cement solidification / stabilization technology can effectively seal hexavalent chromium and trivalent chromium in an inert solid matrix to reduce the toxicity of polluted soil, but it does not fundamentally change the form of hexavalent chromium, causing re-pollution At the same time, the high alkalinity of cement solidification will change the acid-base balance of soil and water, which will have adverse effects on surrounding organisms; microbial restoration technology has strict requirements on environmental conditions such as temperature and pH, which are difficult to meet during on-site construction, and its restoration efficiency is easy. Affected; the aqueous solution irrigation method uses a large amount of chemicals, and the acid-base environment is single (the reduction of hexavalent chromium and the precipitation of trivalent chromium cannot be guaranteed at the same time), and it is not suitable for formations with low permeability coefficients such as clay. Ferrous Sulfate (FeSO 4 ), sodium metabisulfite (Na 2 S 2 o 5 ), ferrous chloride (FeCl 2 ) and other reducing agents contain a large amount of corrosive anions, which will cause secondary pollution to the soil and groundwater, and the safety of cement, steel bars and other structures in dangerous underground projects

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