Fixing agent for repairing arsenic-polluted soil, and preparation and application method thereof

A fixative and arsenic-polluted technology, which is applied in the field of fixatives for repairing arsenic-contaminated soil, can solve the problems of pH value influence, inconvenient use, adverse effects of physical and chemical properties, etc., and achieve simple and convenient production operation, low cost, and favorable cultivation of crops Effect

Inactive Publication Date: 2014-04-23
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The iron salt solution will have adverse effects on the physical and chemical properties of the soil, especially the pH value of the soil. Quicklime is still needed for pH adjustment, which makes it inconvenient to use

Method used

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  • Fixing agent for repairing arsenic-polluted soil, and preparation and application method thereof
  • Fixing agent for repairing arsenic-polluted soil, and preparation and application method thereof
  • Fixing agent for repairing arsenic-polluted soil, and preparation and application method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] To prepare the fixative for repairing arsenic-contaminated soil of the present invention:

[0032] (1) Prepare a ferrous sulfate solution with a ferrous ion concentration of 0.04-1.2mol / L;

[0033] (2) Add oxidant hydrogen peroxide to the above solution while stirring, oxidant and Fe 2+ The molar ratio is 1:1-2; the reaction is 6-24h, and then the residue is washed 2-3 times with an acid with a pH of about 1.5-3 during suction filtration, and then washed 2-3 times with pure water to collect the residue.

[0034] (3) Dissolve the above residue at 30-70℃7 <pH After reacting for 6-24 hours in <9NaOH solution, suction filter, dry the obtained residue at 40-70°C, and grind through a 100-mesh sieve to obtain a chemical fixative.

Embodiment 2

[0036] In this example, weigh 10g of arsenic-contaminated soil in each Erlenmeyer flask, and add the fixative of Example 1 prepared under different temperature conditions with a mass ratio of 4% to the contaminated soil, according to the soil-water mass ratio of 2:1 Add tap water and stir until uniform. After standing for 7 to 14 days, samples were taken to determine the content of water-soluble As and effective As (sodium bicarbonate extractant) in the soil. After testing, the content of water-soluble As and sodium bicarbonate extractable As in the soil after the fixation prepared at a lower temperature was reduced from 27.11mg / kg and 312.49mg / kg to 0.98mg / kg and 156.28mg, respectively / kg, the fixation rate of water-soluble state is 96.38%, and the fixation rate of sodium bicarbonate leaching state is 49.99%; the content of water-soluble As and sodium bicarbonate leaching As in the soil after fixation prepared at higher temperature Reduced from the original 27.11mg / kg and 31...

Embodiment 3

[0038] The experiment soil was collected from Shimen, Hunan Province, and passed through a 20-mesh nylon sieve after air-drying, removing impurities and grinding. In this example, 10g of arsenic contaminated soil is weighed in each Erlenmeyer flask, and chemical fixatives are added to the soil at a mass ratio of 1%, 2%, 4%, 4.5%, 5%, 6%, 8%, and 10%. To the contaminated soil, add tap water according to the soil-water mass ratio of 2:1 and stir until uniform. After standing for 7 to 14 days, samples were taken to determine the content of water-soluble As and effective As (sodium bicarbonate extractant) in the soil. After testing, when the amount of fixative added is 4%, the content of water-soluble As and sodium bicarbonate extractable As in the soil are reduced from 33.17mg / kg and 226.78mg / kg to 0.94mg / kg and 104.86mg / respectively. kg, the fixation rate of water-soluble state is 97.17%, and that of sodium bicarbonate extract state is 53.76%.

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Abstract

The invention discloses a fixing agent for repairing arsenic-polluted soil, and preparation and an application method thereof. The preparation of a chemical fixing agent comprises the following steps: 1) preparing a solution by using ferrous sulfate as a raw material, slowly adding an oxidant to the solution while stirring, collecting sediments after reacting for a period of time; 2) adding a sodium hydroxide solution to the collected sediments; filtering after reacting for 6-24 hours; and baking residues at 40-70 DEG C, grinding and sieving by a 100-mesh sieve, so as to obtain the chemical fixing agent. After the chemical fixing agent is added to the arsenic-polluted soil, the fixed rates of water-soluble arsenic and effective-state arsenic respectively reach 99.5% and 72.81%; the pH value of the soil does not need to be adjusted when the chemical fixing agent is in use, the physicochemical property of the soil is not destroyed, and the repaired soil is still applicable to plant growth.

Description

Technical field [0001] The invention belongs to the field of arsenic-contaminated soil treatment, and specifically relates to a fixative for repairing arsenic-contaminated soil and a preparation and application method thereof. Background technique [0002] Mine mining and the discharge of the three industrial wastes containing arsenic will cause arsenic pollution in the soil. Soil arsenic pollution will reduce crop yields and cause agricultural product safety issues. Arsenic in the soil may cause harm to human health through the food chain, drinking water or direct contact. At present, my country urgently needs arsenic-contaminated soil remediation technology. [0003] Soil pollution is persistent and difficult to control. At present, how to safely and effectively control arsenic-contaminated soil has become a research hotspot. The treatment methods of contaminated soil include leaching method, electrochemical method, vitrification method, fixation / stabilization method, phytoreme...

Claims

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Application Information

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IPC IPC(8): C09K17/02B09C1/08C09K101/00
Inventor 杨志辉柴立元刘琳廖映平李青竹杨卫春
Owner CENT SOUTH UNIV
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