Application of magnesium-aluminum double-metal hydroxide loaded ferrous sulfide composite material in soil remediation

A hydroxide and composite material technology, applied in the field of environmental functional materials and soil treatment, can solve problems such as lack of research, damage to soil structure, soil acidification, etc., to achieve wide application prospects, improve reaction performance, and stabilize the effect.

Pending Publication Date: 2022-01-14
JINAN UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, studies have shown that adding alkaline materials such as lime, slag, fly ash, etc. to the soil if the soil pH is too high will destroy the soil structure and cause the alkalization of the soil, and the impact of alkaline materials on various microbial indicators of the soil is unknown ; Phosphate curing agents such as phosphate ore, hydroxyapatite, diammonium hydrogen phosphate, etc., will cause acidification of the soil after being added to the soil, destroying the original structure of the soil; zeolite, sodium bentonite, sepiolite and other clay The influence of metal oxide-based materials on the easy migration of heavy metals such as carbonate binding state is unknown, and the research on soil physical and chemical properties such as soil pH and soil microbial properties is still lacking; the adsorption capacity of metal oxide-based curing agents increases with the decrease of soil pH. Weakened, it is necessary to use soil pH regulators to strengthen the adsorption and fixation; the heavy metals immobilized by organic materials may be activated again with the degradation of organic matter, and the mechanism of their interaction with soil, microorganisms, and plants is not yet clear
At present, the treatment effect of commonly used passivating agents needs to be improved, and there is a lack of research on the long-term stability of heavy metals after treatment; in addition, after the remediation materials are added to the soil, there is still a lack of understanding of the impact on soil physical and chemical properties and microbial properties, and further research is still needed

Method used

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  • Application of magnesium-aluminum double-metal hydroxide loaded ferrous sulfide composite material in soil remediation
  • Application of magnesium-aluminum double-metal hydroxide loaded ferrous sulfide composite material in soil remediation
  • Application of magnesium-aluminum double-metal hydroxide loaded ferrous sulfide composite material in soil remediation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Example 1FeS@Mg 2 Preparation of Al-LDH

[0034] (1)Mg 2 Al-LDH is prepared by the following method:

[0035] With water as the carrier, the AlCl 3 ·6H 2 O and MgCl 2 ·6H 2 O (mass ratio = 1:1.68) was mixed and reacted under magnetic stirring at room temperature for 30 minutes, and the pH was adjusted to 10 with ammonia water. After the white colloid was formed, it was allowed to stand at room temperature for 60 minutes, and the white colloid was centrifuged and washed with deionized water. Dry in an oven at 80°C for 24 hours to obtain Mg 2 Al-LDH material.

[0036] (2) FeS@Mg 2 Al-LDH is prepared by the following method:

[0037] Under the condition of nitrogen protection (removal of dissolved oxygen), 1.58g of FeSO 4 ·7H 2 O(0.0057mol Fe 2+ ) into 485mL deionized water; then add 0.5g of Mg 2 Al-LDH, magnetic stirring for 30min; then add 15mL of 378.80mM Na dropwise 2 S·9H 2 O, magnetic stirring for 30 minutes. To ensure complete reaction and nanomaterial...

Embodiment 2

[0038] Example 2 FeS@Mg of different times and different dosages 2 Effect of Al-LDH on Stabilization Efficiency of Mercury in Contaminated Soil

[0039] The soil is silty loam (36.8% sandy soil, 51.6% silt content, 14.0% clay content), collected from 0-30cm mercury-free surface soil of Nankai University in Tianjin (the latitude and longitude of the site is 117.34 / 38.99). After the samples are often warm and air-dried, impurities such as gravel are removed, ground, passed through a 10-mesh sieve, washed three times with tap water to remove suspended colloids and water-leaching components, then air-dried, and stored in sealed plastic buckets for later use. The pretreated soil was mixed with mercury nitrate solution in a closed polyethylene container for 90 days, and after 24 hours of gravity sedimentation, the supernatant was separated and the soil was air-dried at room temperature for 7 days. It was determined that the final mercury content in the soil was 200-240mg / kg.

[00...

Embodiment 3

[0045] Example 3FeS@Mg 2 Changes of mercury in soil before and after Al-LDH treatment

[0046] image 3 Compared with FeS@Mg 2 Al-LDH (amount of 0.1% and 1%) treated soil before and after the change of mercury in the soil form. The exchangeable (EX), carbonate-bound (CB), iron-manganese oxide-bound (OX), organic-bound (OM) and residual (RS) mercury in the untreated soil accounted for 3% respectively , 0.1%, 0.9%, 86.1%, 9.9%. Add 0.1% FeS@Mg 2 In the Al-LDH soil, the exchangeable state and the carbonate-bound state were almost completely transformed into the organic-bound state (88.8%) and the residue state (10.2%). When FeS@Mg 2 When the amount of Al-LDH increased to 1%, the contents of organic bound state and residue state were 70.3% and 29.0%, respectively. The increase of residue state may be due to the increase in the amount of composite materials, and the heavy metal state continues to be more stable and difficult to migrate. migrate.

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Abstract

The invention belongs to the technical field of environmental functional materials and soil treatment, and discloses an application of a magnesium-aluminum double-metal hydroxide loaded ferrous sulfide composite material in soil remediation. The influence of the composite material dosage and the reaction time on the soil mercury remediation effect is studied, and the change of the mercury existence form in the soil before and after material treatment is studied; and the influence of the application of the composite material on soil properties is studied. The use amount and reaction time of the composite material required for enabling the leaching concentration of mercury in the soil to reach the III-class standard of the groundwater environmental quality standard (GB/T 14848-2017) are determined, the stabilized mercury has long-term stability, the environmental risk of mercury in the soil is remarkably reduced by adding the composite material, the pH value and microbiological indexes of the soil are effectively improved, and the cyclic regeneration capability of the soil ecological environment is promoted. The remediation technology is simple to operate, short in reaction time and capable of persistently and efficiently stabilizing mercury, and has a wide application prospect in environmental remediation.

Description

technical field [0001] The invention belongs to the technical field of environmental functional materials and soil treatment, and in particular relates to the application of a magnesium-aluminum double metal hydroxide-loaded ferrous sulfide composite material in soil restoration. Background technique [0002] Mercury is one of the most toxic heavy metal elements. It has the characteristics of neurotoxicity, teratogenicity, accumulation and heredity. The US Environmental Protection Agency has listed it as one of the priority pollutants. The sources of mercury are mainly divided into natural emissions and man-made emissions: natural emissions are mainly natural weathering and crustal activities, etc.; man-made emissions refer to the production processes such as chlor-alkali industry, coal combustion, mercury metallurgy and construction (cement) that discharge a large amount of mercury into the environment . The National Soil Pollution Survey Bulletin released in 2014 shows th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/08
CPCB09C1/08B09C2101/00
Inventor 宫艳艳胡冠钊王丽娟白杨
Owner JINAN UNIVERSITY
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