Composite material containing FeS2 and reduced iron as well as preparation method and application of the composite material

A technology of composite materials and reduced iron, which is applied in the field of soil pollution remediation, can solve problems such as difficult engineering application, complicated preparation methods, and low remediation efficiency, and achieve the effects of low cost, simple preparation method, and low price

Active Publication Date: 2020-06-05
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the traditional reducing and stable repair agents such as ferrous sulfate, zero-valent iron powder, sodium sulfide, etc., have problems such as low repair efficiency and secondary pollution.
Some high-efficiency synthetic materials commonly reported, such as nano-zero-valent iron, are complicated to prepare, expensive, and difficult for engineering applications. Therefore, research on efficient, green and relatively economical repair materials and their preparation methods is the key to solving hexavalent chromium-contaminated soil

Method used

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  • Composite material containing FeS2 and reduced iron as well as preparation method and application of the composite material
  • Composite material containing FeS2 and reduced iron as well as preparation method and application of the composite material
  • Composite material containing FeS2 and reduced iron as well as preparation method and application of the composite material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0060] Select FeS 2 The pyrite whose mass fraction is greater than 95% is dried, vibrating and sieved through 20 mesh to obtain pyrite particles; fully mix the pyrite and iron powder (over 20 mesh) molar ratio of 9:1, add the total mass of The citric acid with a fraction of 1% is put into a hard stainless steel ball mill tank, and balls are added according to a ball-to-material ratio of 15:1. The ball mill is an omnidirectional planetary ball mill, and the ball mill speed is set to 400 rpm. After 4 hours of mechanical ball milling, After sieving through 100 meshes, the required hexavalent chromium-contaminated soil remediation material is obtained.

Embodiment 2

[0062] Select the tailings of an iron ore, crush it, take a high-purity pyrite sample, wash and air-dry it, and then grind it through a 20-mesh sieve (the contents of Fe and S are 47.33% and 51.68%, respectively, according to chemical composition analysis), and obtain Pyrite particles; fully mix according to the molar ratio of pyrite and iron powder (over 20 mesh) 9:1, add citric acid with a total material mass fraction of 1%, put it into a hard stainless steel ball mill tank, and press the ball-to-material ratio of 15 : 1 Add grinding balls, the ball mill is an omnidirectional planetary ball mill, the setting ball milling speed is 400 rpm, after mechanical ball milling for 4 hours, sieve through 100 meshes to obtain the required hexavalent chromium-contaminated soil remediation material.

Embodiment 3

[0064] Weighing 20g of contaminated soil with a hexavalent chromium content of 448.1mg / kg is placed in a polytetrafluoroethylene beaker, adding 1g of the economical and easy-to-preparation hexavalent chromium-contaminated soil restoration material described in Example 1, according to the soil-water mass ratio 2:1 Add pure water and stir until uniform. The samples were taken at the reaction time of 1, 2, 5, 7, 14, and 30 days, and then dried at 60°C for 6 hours. The content of hexavalent chromium in the soil was extracted by alkaline digestion (EPA METHOD 3060B). Phenylcarbazide spectrophotometric determination of hexavalent chromium concentration. Experimental results such as Figure 7 As shown, after 30 days of treatment, the concentration of total hexavalent chromium in the soil was 2.5mg / kg, and the removal rate of total hexavalent chromium in the soil reached 99.44%.

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PUM

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Abstract

The invention provides a composite material containing FeS2 and reduced iron as well as a preparation method and application of the composite material. The method comprises the following steps: mixinga substance with a FeS2 content of 95% or above with reductive iron powder, adding a chelating agent, fully mixing, carrying out ball milling, taking out, and sieving to obtain a remediation material. When the to-be-remediated soil is added into the hexavalent chromium contaminated soil, the reduction rate of hexavalent chromium reaches 99% or above. The economic hexavalent chromium contaminatedsoil remediation material easy to prepare is expected to fully utilize metal tailings, one-step preparation is achieved, the preparation method is simple, the cost is low, and the problem that tailings are difficult to stack during large-scale preparation is expected to be solved; and the prepared remediation material has a good reduction remediation effect on hexavalent chromium contaminated soilunder external field conditions such as microwaves and the like, is short in time and can be efficiently used for remediation of hexavalent chromium contaminated soil.

Description

technical field [0001] The invention relates to the technical field of soil pollution remediation, in particular to an economical and easy-to-prepare FeS-containing 2 and reduced iron restoration materials and methods for their preparation and application. Background technique [0002] Chromium and its compounds are typical heavy metal pollutants produced by the chromium chemical industry. At present, there are still more than 40 chromium slag dumps and more than 30 abandoned chromium salt factories in China. Due to the lack of environmental risk control measures such as pollutant migration barriers, the soil in the chromium chemical industry chrome waste dump and abandoned plant sites has been seriously polluted. Chromium usually exists in two forms of Cr(VI) and Cr(III). The toxicity of Cr(VI) is about 100 times higher than that of Cr(III), and hexavalent chromium in the environment can enter the soil through various ways. Water-soluble Cr(VI) is listed as one of the ei...

Claims

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Application Information

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IPC IPC(8): C09K17/40B09C1/08
CPCB09C1/08C09K17/40
Inventor 杨卫春李琦闵小波杨志辉张晓明廖骐石岩
Owner CENT SOUTH UNIV
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