Method for regenerating and recycling waste leaching liquid used for heavy metal contaminated soil

A technology for polluted soil and heavy metals, which is applied in the field of polluted soil environmental management to achieve the effects of reducing the risk of secondary pollution, solving treatment problems and low cost

Inactive Publication Date: 2019-04-16
TAIYUAN UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Aiming at the deficiencies in existing methods for regenerating waste liquid from chemical leaching of heavy metal-contaminated soils, the purpose of the present invention is to provide a method capable of realizing the regeneration and recycling of waste liquid from chemical leaching. The method is simple in operation, low in cost, and suitable for promotional use

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] 1. Preparation of mixed eluent

[0031] The eluent is mixed with GLDA and citric acid in a molar ratio of 2:5, and the concentration of the mixed eluent is 50mmol·L -1 , pH value is 3.50.

[0032] 2. Generation of washing waste liquid

[0033] Basic properties of Cu-contaminated soil: the total Cu content in the soil is 543mg kg -1 , pH value 5.36, clay / silt / sand 19 / 56 / 25, organic matter content 16.6g·kg -1 , the cation exchange capacity is 9.4cmoL·kg -1 .

[0034] Weigh 10g of contaminated soil into a 250mL beaker, add 100mL of mixed eluent, 150r min -1 Stirring at a frequency of 4 hours, the solid-liquid separation is carried out after 4 hours of reaction, and the liquid produced at this time is the leaching waste liquid; the Cu concentration of the leaching waste liquid is 35mg L -1 , the pH value was 3.86, and the removal rate of Cu in the polluted soil was 64.4%.

[0035] 3. Preparation of regenerant

[0036] Soak acid (concentration is 10wt%HNO 3 ) overni...

Embodiment 2

[0041] 1. Preparation of mixed eluent

[0042] The eluent is mixed with EDTA, GLDA and citric acid in a molar ratio of 1:1:3, and the concentration of the mixed eluent is 100mmol·L -1 , the pH value is 3.73.

[0043] 2. Generation of washing waste liquid

[0044] Basic properties of polluted soil: the total Cu content in the soil is 289mg·kg -1 , the total Pb content is 1420mg·kg -1 , pH value 7.36, clay / silt / sand 9 / 36 / 55, organic matter content 36.6g·kg -1 , the cation exchange capacity is 20.4cmoL·kg -1 .

[0045] Weigh 10g of contaminated soil into a 250mL beaker, add 100mL of mixed eluent and place it in a shaker at 150r·min -1 Oscillate at a frequency of 4 hours, and after 4 hours of reaction, solid-liquid separation is carried out by centrifugation. The liquid produced at this time is the leaching waste liquid; the Cu concentration of the leaching waste liquid is 15mg L -1 , Pb concentration is 115mg L -1 , pH value is 4.86, the removal rate of Cu in polluted soi...

Embodiment 3

[0052] 1. Preparation of mixed eluent

[0053] The eluent is mixed with EDTA, GLDA and citric acid in a molar ratio of 1:3:5, and the concentration of the mixed eluent is 100mmol·L -1 , pH value is 4.56.

[0054] 2. Generation of washing waste liquid

[0055] Basic properties of polluted soil: the total Cu content in the soil is 263mg·kg -1 , the total Pb content is 654mg·kg -1 , the total Cd content is 8.3mg·kg -1 , pH value is 7.05, clay / silt / sand is 12 / 34 / 54, organic matter content is 33.6g·kg -1 , the cation exchange capacity is 19.5cmoL·kg -1 .

[0056] Weigh 10g of contaminated soil into a 250mL beaker, add 100mL of mixed eluent and place it in a shaker at 150r·min -1 Oscillating at a frequency of 4 hours, centrifugation is used to separate the solid and liquid after 4 hours of reaction. The liquid produced at this time is the leaching waste liquid; the Cu concentration of the leaching waste liquid is 18 mg L -1 , the Pb concentration is 49.1mg·L -1 , the concen...

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Abstract

The invention discloses a method for regenerating and recycling waste leaching liquid used for heavy metal contaminated soil. The method comprises the steps that a carrier is flushed by water, soakedin acid overnight, flushed to be neutral and dried, domesticated sulfate reducing bacteria is inoculated in a culture medium and cultured for 2-3 days, culturing liquid completely becomes black, the dried carrier is placed in the culturnign liquid, the mass ratio of sulfate reducing bacteria liquid and the carrier is (10-20):1, the stirring reaction is conducted for 1-2 days in a culturing box atthe constant temperature of 35 DEG C or 39 DEG C, solid-liquid separation is conducted; after a solid sample is dried, a waste leaching liquid regenerant is obtained. The method can regenerate and recycle the chemical waste leaching liquid and has the advantages that the operation is simple, the cost is low, and the method is suitable for using and popularization.

Description

technical field [0001] The invention belongs to the technical field of environmental treatment of polluted soil, and in particular relates to a method for regenerating and recycling heavy metal polluted soil leaching waste liquid by using immobilized sulfate-reducing bacteria. Background technique [0002] In recent years, the problem of heavy metal pollution in soil has aroused widespread concern from all walks of life. For heavy metal-contaminated soil, researchers have developed many remediation technologies, including physical remediation, chemical remediation, and biological remediation technologies. Compared with other remediation technologies, chemical remediation technology has the advantages of high efficiency, stability, and thoroughness. Soil leaching is an effective chemical remediation technology. It can not only quickly remove heavy metals from the soil, but also has the most thorough removal effect of heavy metals. It is especially suitable for the treatment o...

Claims

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Application Information

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IPC IPC(8): B09C1/02
CPCB09C1/02
Inventor 郭晓方韩玮吉莉张桂香郑伟何秋生
Owner TAIYUAN UNIVERSITY OF SCIENCE AND TECHNOLOGY
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