Method for remediating chromium polluted soil by enabling super fine iron powder to cooperate with microorganisms

Abstract

The invention belongs to the technical field of ecological remediation, and discloses a method for remediating chromium polluted soil by enabling super fine iron powder to cooperate with microorganisms. The method comprises the following step of: sufficiently mixing the super fine iron powder and mixed bacteria with the chromium polluted soil to culture, thereby completing remediation of chromiumpolluted soil, wherein the mixed bacteria comprise chromium reducing bacteria, iron reducing bacteria and sulphate reducing bacteria. According to the method disclosed by the invention, the characteristic of corroding and releasing H2, in a remediation process, of the super fine iron powder is sufficiently utilized, and the microorganisms which take H2 as an electron donor are induced to grow andbreed on the surface, so that the microorganisms obtain energy, high-valence-state high-toxicity hexavalent chromium is reduced to be low-valence-state low-toxicity trivalent chromium, and the low-valence-state low-toxicity trivalent chromium is converted into occurrence forms, which are difficult in bioavailability, such as an iron-manganese combined form, an organic combined form and a residualform from a water-soluble form, an exchangeable form and a carbonate combined form, and therefore, transfer ability and bioavailability, in the soil, of chromium are reduced.

Description

technical field [0001] The invention belongs to the technical field of ecological restoration, and in particular relates to a method for restoring chromium-contaminated soil with ultrafine iron powder and microorganisms. Background technique [0002] As an important raw material, chromium is widely used in industries such as electroplating, tanning, metal processing, paint and wood preservation. Due to the open-air stacking and leakage of chromium slag, dripping and leakage of chromium during use, non-standard discharge of wastewater and infiltration of chromium-containing sludge, etc., a large amount of chromium enters the surrounding and downstream soil environment of the site, resulting in serious soil chromium pollution. In the soil environment, chromium often exists in two forms: hexavalent chromium (Cr(VI)) and trivalent chromium (Cr(III)). Trivalent chromium is easily adsorbed by soil colloids and precipitates due to its positive charge, which is relatively less toxi...

AI Technical Summary

Problems solved by technology

Therefore, once Fe 0 The surface is covered by ferrochromium precipitates, and the reduction reaction of hexavalent chromium will be terminated, resulting in adsorption and fixation on Fe 0 Hexavalent chromium on the surface is re-released into the soil, greatly reducing the remediation effect of zero-valent iron in chromium-contaminated soils

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