Method for remediating heavy metal-contaminated sediment and method for improving farmland soil by using modified zeolite molecular sieve

A zeolite molecular sieve and modified zeolite technology, which is applied in the field of farmland soil improvement, can solve problems such as occupancy, unsatisfactory effect, and influence on adsorption efficiency, and achieve the effects of improving soil, realizing resource reuse, and improving the ability to absorb heavy metals

Active Publication Date: 2019-08-23
HUNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, different from soil, the total organic matter content of river and lake sediments and the organic matter content of clay components are much higher than that of soil, and the combination of heavy metals and organic matter is strong, so that the stabilizer, which is originally very effective in treating soil, can be used when treating sediment. The effect is not ideal
In addition, due to the presence of impurities in industrial zeolites, the adsorption sites are occupied during the heavy metal adsorption process, which affects the adsorption efficiency.

Method used

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  • Method for remediating heavy metal-contaminated sediment and method for improving farmland soil by using modified zeolite molecular sieve
  • Method for remediating heavy metal-contaminated sediment and method for improving farmland soil by using modified zeolite molecular sieve
  • Method for remediating heavy metal-contaminated sediment and method for improving farmland soil by using modified zeolite molecular sieve

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] A kind of method utilizing modified zeolite molecular sieve of the present invention to repair heavy metal polluted bottom mud, comprises the following steps:

[0035] (1) Preparation of modified zeolite molecular sieve materials

[0036] (1.1) Prepare the solution

[0037] Configure 1mol / L HNO 3 Solution: measure 12.8ml HNO 3 Add 50ml of deionized water, dilute to 200ml, stir well to get HNO 3 solution.

[0038]Prepare 1mol / L NaOH solution: weigh 8.0g NaOH and dissolve it in 200ml deionized water, stir well to obtain NaOH solution.

[0039] Prepare 0.5mol / L NaOH solution: weigh 4.0g NaOH and dissolve in 200ml deionized water, stir well to obtain NaOH solution.

[0040] Prepare chitosan solution: Weigh 10g chitosan (used to treat 10g zeolite molecular sieve) in 200ml deionized water.

[0041] (1.2) Preparation of granular zeolite molecular sieves: Grind industrial clinoptilolite molecular sieves (original form, particle size > 2mm) into small particles using a pul...

Embodiment 2

[0052] A method of using modified zeolite molecular sieve of the present invention to restore heavy metal-contaminated bottom mud, its steps are basically the same as in Example 1, the only difference is that the mass ratio of modified zeolite molecular sieve to bottom mud sample in Example 2 is 3:2 .

[0053] Speciation detection of Cu(II), Cd(II), Pb(II), Zn(II) in sediment:

[0054] Take the bottom sludge treated with the modified zeolite molecular sieve in Example 2, use the BCR continuous extraction method to carry out graded extraction of metals in the exchangeable state, reducible state, oxidizable state and residue state, and the obtained extract is determined by atomic absorption spectrometer. The content of metals; at the same time, take the unrepaired heavy metal contaminated sediment, and use the same method to detect the forms of Cu(II), Cd(II), Pb(II), Zn(II), the results are as follows Figure 4 shown. Figure 4 It is a change diagram of the content of heavy m...

Embodiment 3

[0057] A method of using modified zeolite molecular sieve of the present invention to restore heavy metal-contaminated bottom mud, the steps of which are basically the same as in Example 1, the only difference being that the mass ratio of modified zeolite molecular sieve to bottom mud sample in Example 3 is 1:9 .

[0058] Speciation detection of Cu(II), Cd(II), Pb(II), Zn(II) in sediment:

[0059] Take the bottom sludge treated with the modified zeolite molecular sieve in Example 3, use the BCR continuous extraction method to carry out graded extraction of metals in the exchangeable state, reducible state, oxidizable state and residue state, and the obtained extract is determined by atomic absorption spectrometer. The content of metals; at the same time, take the unrepaired heavy metal contaminated sediment, and use the same method to detect the forms of Cu(II), Cd(II), Pb(II), Zn(II), the results are as follows Figure 5 shown. Figure 5 It is a change diagram of the conten...

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Abstract

The invention discloses a method for remediating heavy metal polluted sediment by use of a modified zeolite molecular sieve and a farmland soil improvement method. The remediating method comprises the following steps: mixing a modified zeolite molecular sieve with heavy metal polluted sediment; and performing a fixing-stabilizing reaction of the obtained mixture to finish remediation of the heavy metal polluted sediment, wherein the modified zeolite molecular sieve is prepared by modifying a zeolite molecular sieve with chitosan. The improvement method comprises the following step: mixing farmland soil with the remediated sediment to finish improvement of the farmland soil. According to the method, the heavy metal polluted sediment is remediated by use of the modified zeolite molecular sieve, the occurrence form of heavy metals in sediment is changed, and the harm of heavy metals to the aquatic biological environment is reduced; and moreover, the remediated sediment returns to the land for soil improvement, the soil fertility and ecological index can be improved, and an aim of resource recycling is achieved while polluted sediment is remediated.

Description

technical field [0001] The invention belongs to the field of sediment pollution restoration in environmental and water conservancy projects, and relates to a method for repairing heavy metal-contaminated sediment by using modified zeolite molecular sieves and an improvement method for farmland soil. Background technique [0002] River and lake sediment is an important part of the aquatic ecosystem. It is not only a nutrient pool, but also a storage pool for pollutants. The bottom mud of rivers and lakes contains a large amount of heavy metals, which are highly toxic, high in content, difficult to degrade, easy to accumulate in the food chain, and seriously threaten the aquatic ecosystem and human health. Under certain hydrodynamic conditions, the heavy metals in the sediment will be released into the overlying water through interfacial diffusion and resuspension, which will increase the concentration of heavy metals in the water and deteriorate the water quality. At present...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F11/00C02F11/18C05G3/04C05G3/00C02F101/20C05G3/80
CPCC02F11/008C02F11/18C02F2101/20C05D9/00C05G3/00C05G3/80C05F7/00
Inventor 文嘉曾光明易元杰彭志龙
Owner HUNAN UNIV
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