Hexavalent chromium pollution in-situ repairing agent FeSx, preparation and application

Abstract

The invention discloses hexavalent chromium pollution in-situ repairing agent FeSx, preparation and application. The preparation includes: preparing a solution of water-soluble sulfur-containing regent as well as water-soluble iron-containing reagent, mixing well at pH 3.0-8.0, and carrying out solid-liquid separation to obtain solid that is iron polysulfide (FeSx), used as in-situ repairing agent for hexavalent chromium polluted soil and underwater.

Description

technical field

[0001] The invention relates to an in-situ restoration agent for hexavalent chromium polluted soil and groundwater, a preparation method and a use method thereof. Specifically, FeS was prepared using water-soluble iron-containing reagents and water-soluble sulfur-containing reagents x , and apply it to the in-situ remediation of hexavalent chromium-contaminated soil, to restore and fix the hexavalent chromium in the soil, which is easy to migrate, has high toxicity and has phytotoxicity, and realizes the in-situ remediation of hexavalent chromium-contaminated soil and groundwater. Background technique

[0002] The "National Soil Pollution Survey Bulletin" released in April 2014 shows that my country's soil is seriously polluted by heavy metals. Chromium is one of the eight major heavy metal pollutants, and the national chromium pollution rate is 1.1%. There are many sources of chromium in soil, among which the most serious hazards mainly include three aspec...

Examples

Embodiment 1

[0031] Embodiment 1 (soil remediation case)

[0032] (1) Dissolving 10 kilograms of ferric sulfate in 90 kilograms of water is configured into a solution with a mass concentration of 10%, and the pH is adjusted to 6;

[0033] 15.6 kilograms of sodium sulfide are added in the above-mentioned solution, and the pH is adjusted to 6 to obtain the precursor suspension of the restoration agent;

[0034] Aging the precursor suspension of the above restoration agent for 24 hours, and centrifuging to obtain the hexavalent chromium soil in-situ restoration agent FeS x 5.5 kg.

[0035] (2) The remediation object is a certain soil polluted by hexavalent chromium. The content of hexavalent chromium in the soil is 4628.9mg / kg. 5.5 kg FeS x Mix evenly with 300 kg of polluted soil, the dosage ratio used is 1.83%. After remediation, the hexavalent chromium content in the soil is less than 1mg / kg, the hexavalent chromium toxicity leaching amount is less than 0.1mg / L, and the total chromium ...

Embodiment 2

[0036] Embodiment 2 (soil remediation case)

[0037] (1) 4 kilograms of ferrous chloride are dissolved in 96 kilograms of water, and it is configured into a solution that the mass concentration is 4%, and the pH is adjusted to 8;

[0038] 6.3 kilograms of calcium pentasulfide are added to the above-mentioned solution, and the pH is adjusted to 8 to obtain the precursor suspension of the restoration agent;

[0039] Aging the precursor suspension of the above restoration agent for 0.5 hours, and centrifuging to obtain the hexavalent chromium soil in-situ restoration agent FeS x About 6.2 kg.

[0040] (2) The remediation object is a certain soil polluted by hexavalent chromium. The content of hexavalent chromium in the soil is 2572.4mg / kg. 6.2 kg FeS x Mixed with 620 kg of contaminated soil, the dose used was 1.0%. After remediation, the hexavalent chromium content in the soil is less than 1mg / kg, the hexavalent chromium toxicity leaching amount is less than 0.1mg / L, and the...

Embodiment 3

[0041] Embodiment 3 (soil remediation case)

[0042] (1) 0.1 kilogram of ferrous sulfate is dissolved in 99.9 kilograms of water, is configured into the solution that mass concentration is 0.1%, adjusts pH to 3;

[0043] 0.11 kg of potassium hydrosulfide is added to the above solution, and the pH is adjusted to 3 to obtain the precursor suspension of the restoration agent;

[0044] Aging the above repair agent precursor suspension for 10 hours, and centrifuging to obtain hexavalent chromium soil in-situ repair agent FeS x 0.05 kg.

[0045] (2) The remediation object is a certain soil polluted by hexavalent chromium. The content of hexavalent chromium in the soil is 526.3mg / kg. 0.05 kg FeS x Mixed with 16.7 kg of contaminated soil, the dose used was 0.3%. After remediation, the hexavalent chromium content in the soil is less than 1mg / kg, the hexavalent chromium toxicity leaching amount is less than 0.1mg / L, and the total chromium toxicity leaching amount is less than 2mg / L...

technical field

[0001] The invention relates to an in-situ restoration agent for hexavalent chromium polluted soil and groundwater, a preparation method and a use method thereof. Specifically, FeS was prepared using water-soluble iron-containing reagents and water-soluble sulfur-containing reagents x , and apply it to the in-situ remediation of hexavalent chromium-contaminated soil, to restore and fix the hexavalent chromium in the soil, which is easy to migrate, has high toxicity and has phytotoxicity, and realizes the in-situ remediation of hexavalent chromium-contaminated soil and groundwater. Background technique

[0002] The "National Soil Pollution Survey Bulletin" released in April 2014 shows that my country's soil is seriously polluted by heavy metals. Chromium is one of the eight major heavy metal pollutants, and the national chromium pollution rate is 1.1%. There are many sources of chromium in soil, among which the most serious hazards mainly include three aspec...

Examples

Embodiment 1

[0031] Embodiment 1 (soil remediation case)

[0032] (1) Dissolving 10 kilograms of ferric sulfate in 90 kilograms of water is configured into a solution with a mass concentration of 10%, and the pH is adjusted to 6;

[0033] 15.6 kilograms of sodium sulfide are added in the above-mentioned solution, and the pH is adjusted to 6 to obtain the precursor suspension of the restoration agent;

[0034] Aging the precursor suspension of the above restoration agent for 24 hours, and centrifuging to obtain the hexavalent chromium soil in-situ restoration agent FeS x 5.5 kg.

[0035] (2) The remediation object is a certain soil polluted by hexavalent chromium. The content of hexavalent chromium in the soil is 4628.9mg / kg. 5.5 kg FeS x Mix evenly with 300 kg of polluted soil, the dosage ratio used is 1.83%. After remediation, the hexavalent chromium content in the soil is less than 1mg / kg, the hexavalent chromium toxicity leaching amount is less than 0.1mg / L, and the total chromium ...

Embodiment 2

[0036] Embodiment 2 (soil remediation case)

[0037] (1) 4 kilograms of ferrous chloride are dissolved in 96 kilograms of water, and it is configured into a solution that the mass concentration is 4%, and the pH is adjusted to 8;

[0038] 6.3 kilograms of calcium pentasulfide are added to the above-mentioned solution, and the pH is adjusted to 8 to obtain the precursor suspension of the restoration agent;

[0039] Aging the precursor suspension of the above restoration agent for 0.5 hours, and centrifuging to obtain the hexavalent chromium soil in-situ restoration agent FeS x About 6.2 kg.

[0040] (2) The remediation object is a certain soil polluted by hexavalent chromium. The content of hexavalent chromium in the soil is 2572.4mg / kg. 6.2 kg FeS x Mixed with 620 kg of contaminated soil, the dose used was 1.0%. After remediation, the hexavalent chromium content in the soil is less than 1mg / kg, the hexavalent chromium toxicity leaching amount is less than 0.1mg / L, and the...

Embodiment 3

[0041] Embodiment 3 (soil remediation case)

[0042] (1) 0.1 kilogram of ferrous sulfate is dissolved in 99.9 kilograms of water, is configured into the solution that mass concentration is 0.1%, adjusts pH to 3;

[0043] 0.11 kg of potassium hydrosulfide is added to the above solution, and the pH is adjusted to 3 to obtain the precursor suspension of the restoration agent;

[0044] Aging the above repair agent precursor suspension for 10 hours, and centrifuging to obtain hexavalent chromium soil in-situ repair agent FeS x 0.05 kg.

[0045] (2) The remediation object is a certain soil polluted by hexavalent chromium. The content of hexavalent chromium in the soil is 526.3mg / kg. 0.05 kg FeS x Mixed with 16.7 kg of contaminated soil, the dose used was 0.3%. After remediation, the hexavalent chromium content in the soil is less than 1mg / kg, the hexavalent chromium toxicity leaching amount is less than 0.1mg / L, and the total chromium toxicity leaching amount is less than 2mg / L...

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