Method for remedying heavy metal-contaminated soil by combining chemical reduction and chemical leaching

Abstract

The invention relates to a method for remedying heavy metal-contaminated soil by combining chemical reduction and chemical leaching, and aims to provide a method for remediation by virtue of combination of chemical reduction and chemical leaching. The method is used for eluting iron and manganese oxides to improve an effect of removing heavy metals from soil by using a leaching agent. The method comprises the following steps of performing leaching by using a reducing agent aqueous solution, namely performing vibratory washing on the contaminated soil by using the reducing agent aqueous solution, and filtering washing liquid after centrifugation; and performing leaching by using a Na2EDTA (Ethylene Diamine Tetraacetic Acid) aqueous solution, namely adding the Na2EDTA aqueous solution into the contaminated soil leached by the reducing agent aqueous solution for vibratory washing, and filtering washing liquid after centrifugation.

Description

technical field

[0001] The invention relates to the field of soil heavy metal pollution treatment and restoration, in particular to a method combining chemical reduction and chemical leaching for eluting heavy metals adsorbed by soil iron and manganese oxides. Background technique

[0002] In recent years, leaching technology has become one of the most important means in the treatment of heavy metal-contaminated soil. The leaching technology not only realizes the separation of heavy metals from the soil, but also has the advantages of quick results and no restrictions on climate and other conditions, and has gradually been widely used. . In the Superfund Program implemented in the United States in the 1990s, large-scale leaching restoration projects have begun. The key to leaching technology lies in the choice of leaching agent. There are many kinds of leaching agents: chelating agent, inorganic leaching agent, surfactant, etc. In a large number of tests and projects at hom...

Examples

Embodiment 1

[0021] The soil around a mining area in Linxiang, Hunan was collected, and its basic physical and chemical properties were measured: arsenic: 46.7mg / kg, cadmium: 1.34mg / kg, lead: 383mg / kg, pH=6.1, and the collected soil was air-dried at room temperature. Air-dried and ground, passed through a 100-mesh sieve, and fully stirred evenly;

[0022] (1) Weigh 10g of soil into a 250ml Erlenmeyer flask, add 100ml of 0.5mol / L Na 2 EDTA aqueous solution, and adjust the pH to 4.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0023] (2) Add 100ml of 0.5mol / L Na 2 EDTA aqueous solution, and adjust the pH to 4.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0024] (3) Add 100ml of deionized water to the re-centrifuged soil, shake at room temperature at...

Embodiment 2

[0026] The soil around a mining area in Linxiang, Hunan was collected, and its basic physical and chemical properties were measured: arsenic: 46.7mg / kg, cadmium: 1.34mg / kg, lead: 383mg / kg, pH=6.1, and the collected soil was air-dried at room temperature. Air-dried and ground, passed through a 100-mesh sieve, and fully stirred evenly;

[0027] (1) Weigh 10g of soil into a 250ml Erlenmeyer flask, add 100ml of 0.5mol / L Na 2 EDTA aqueous solution, and adjust the pH to 4.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0028] (2) Add 100ml of 0.5mol / L NH to the centrifuged soil 2 OH·HCl aqueous solution, and adjust the pH to 1.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0029] (3) Add 100ml of deionized water to the re-centrifuged soil, sh...

Embodiment 3

[0031] The soil around a mining area in Linxiang, Hunan was collected, and its basic physical and chemical properties were measured: arsenic: 46.7mg / kg, cadmium: 1.34mg / kg, lead: 383mg / kg, pH=6.1, and the collected soil was air-dried at room temperature. After air-drying, grind and pass through a 100-mesh sieve, fully stir evenly;

[0032] (1) Weigh 10g of soil into a 250ml Erlenmeyer flask, add 100ml of 0.5mol / L NH 2OH·HCl aqueous solution, and adjust the pH to 1.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0033] (2) Add 100ml of 0.5mol / L Na to the centrifuged soil 2 EDTA aqueous solution, and adjust the pH to 4.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0034] (3) Add 100ml of deionized water to the re-centrifuged soil, shake ...

technical field

[0001] The invention relates to the field of soil heavy metal pollution treatment and restoration, in particular to a method combining chemical reduction and chemical leaching for eluting heavy metals adsorbed by soil iron and manganese oxides. Background technique

[0002] In recent years, leaching technology has become one of the most important means in the treatment of heavy metal-contaminated soil. The leaching technology not only realizes the separation of heavy metals from the soil, but also has the advantages of quick results and no restrictions on climate and other conditions, and has gradually been widely used. . In the Superfund Program implemented in the United States in the 1990s, large-scale leaching restoration projects have begun. The key to leaching technology lies in the choice of leaching agent. There are many kinds of leaching agents: chelating agent, inorganic leaching agent, surfactant, etc. In a large number of tests and projects at hom...

Examples

Embodiment 1

[0021] The soil around a mining area in Linxiang, Hunan was collected, and its basic physical and chemical properties were measured: arsenic: 46.7mg / kg, cadmium: 1.34mg / kg, lead: 383mg / kg, pH=6.1, and the collected soil was air-dried at room temperature. Air-dried and ground, passed through a 100-mesh sieve, and fully stirred evenly;

[0022] (1) Weigh 10g of soil into a 250ml Erlenmeyer flask, add 100ml of 0.5mol / L Na 2 EDTA aqueous solution, and adjust the pH to 4.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0023] (2) Add 100ml of 0.5mol / L Na 2 EDTA aqueous solution, and adjust the pH to 4.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0024] (3) Add 100ml of deionized water to the re-centrifuged soil, shake at room temperature at...

Embodiment 2

[0026] The soil around a mining area in Linxiang, Hunan was collected, and its basic physical and chemical properties were measured: arsenic: 46.7mg / kg, cadmium: 1.34mg / kg, lead: 383mg / kg, pH=6.1, and the collected soil was air-dried at room temperature. Air-dried and ground, passed through a 100-mesh sieve, and fully stirred evenly;

[0027] (1) Weigh 10g of soil into a 250ml Erlenmeyer flask, add 100ml of 0.5mol / L Na 2 EDTA aqueous solution, and adjust the pH to 4.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0028] (2) Add 100ml of 0.5mol / L NH to the centrifuged soil 2 OH·HCl aqueous solution, and adjust the pH to 1.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0029] (3) Add 100ml of deionized water to the re-centrifuged soil, sh...

Embodiment 3

[0031] The soil around a mining area in Linxiang, Hunan was collected, and its basic physical and chemical properties were measured: arsenic: 46.7mg / kg, cadmium: 1.34mg / kg, lead: 383mg / kg, pH=6.1, and the collected soil was air-dried at room temperature. After air-drying, grind and pass through a 100-mesh sieve, fully stir evenly;

[0032] (1) Weigh 10g of soil into a 250ml Erlenmeyer flask, add 100ml of 0.5mol / L NH 2OH·HCl aqueous solution, and adjust the pH to 1.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0033] (2) Add 100ml of 0.5mol / L Na to the centrifuged soil 2 EDTA aqueous solution, and adjust the pH to 4.5 with 0.1mol / L HCl and 0.1mol / L NaOH, shake at room temperature at a horizontal shaking speed of 200rpm for 1h, centrifuge, and separate the soil and washing liquid;

[0034] (3) Add 100ml of deionized water to the re-centrifuged soil, shake ...