Microcapsule composite material for Cd and Pb contaminated soil, preparation method and remediation method

Abstract

The invention discloses a microcapsule composite material for Cd and Pb contaminated soil, a preparation method and a remediation method. The microcapsule composite material comprises the following components in percentage by weight: 20%-50% of modified clay minerals, 30%-50% of a calcium-magnesium-based composite material, 5%-20% of sulfate and 1%-10% of a pH regulator. The microcapsule compositematerial is friendly to the soil environment, does not cause secondary pollution, does not damage the original aggregate structure of the soil, can improve the acid-base buffer capability of the soilto a certain extent, and can improve the water retention of the soil. The treatment effect on Cd and Pb pollution in soil is obvious, the duration time is long, the adaptability to changes of external environment factors is high, and construction is simple.

Description

technical field

[0001] The invention relates to the technical field of soil remediation, in particular to a microcapsule composite material for Cd and Pb polluted soil, a preparation method and a remediation method. Background technique

[0002] Cadmium is a dangerous environmental pollution element with only two valence states of 0 and +2. The average content of cadmium in the lithosphere is between 0.1 and 0.2 mg / kg. Cadmium often coexists with zinc and lead in nature, and cadmium in soil only involves divalent cadmium and its compounds. Cadmium is easily absorbed by plants. As long as the cadmium content in the soil increases slightly, the cadmium content in plants will increase accordingly. Cadmium is highly toxic and is chemically close to zinc. Therefore, in some biochemical processes, cadmium can be used as a chemical analogue of zinc to replace zinc, destroying various carbonases, dehydrogenases and phosphatases related to human respiration and digestion. Similarl...

Examples

preparation example Construction

[0077] The invention provides a kind of preparation method of microcapsule composite material, comprising:

[0078] S1, thermally modifying the clay minerals to obtain modified clay minerals;

[0079] The specific preparation method of modified clay mineral includes:

[0080] 1), pretreatment: naturally dry the clay minerals, crush them, and sieve them through a 200-mesh sieve to obtain clay mineral pretreatment products;

[0081] 2), heat treatment: heat-treat the clay mineral pretreated product to obtain a clay mineral heat-treated product; wherein, the heat-treatment temperature is 200°C-600°C, and the heat-treatment time is 5-7 hours;

[0082] 3) Cooling treatment: putting the heat-treated clay mineral product into a drier for cooling to obtain the modified clay mineral.

[0083] S2, prepare calcium magnesium matrix composite material;

[0084] S3. Mixing the modified clay mineral, the calcium-magnesium-based composite material, the sulfate and the pH regulator accordin...

Embodiment 1

[0104] The samples used in the experiment came from Cd and Pb polluted farmland in a certain area of ​​Tianjin, and the total amount of Cd and Pb in the soil samples was detected by the method stipulated in the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard" (GB15618-2018); Determination of mass effective lead and cadmium The method specified in "Atomic Absorption Method" (GB / T23739-2009) detects the effective concentration of Cd and Pb in soil samples. The test results show that the total amount of Cd in the polluted soil of this farmland is 0.8-1.3mg / kg, the total amount of Pb is 934-680mg / kg, and the pH value is between 7.3-7.8. The goal of soil remediation is to passivate and stabilize the microcapsule composite material After the chemical technology, the effective concentration of cadmium and lead in the soil decreased by 30%.

[0105] The present invention provides a kind of microcapsule composite material of Cd, Pb polluted soil, by w...

Embodiment 2

[0118] The samples used in the experiment came from Cd and Pb polluted farmland in a certain area of ​​Shaoxing, and the total amount of Cd and Pb in the soil samples was detected by the method stipulated in the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard" (GB15618-2018); Determination of mass effective lead and cadmium The method specified in "Atomic Absorption Method" (GB / T23739-2009) detects the effective concentration of Cd and Pb in soil samples. The test results show that the total amount of Cd in the polluted soil of this farmland is 1.2-3.5mg / kg, the total amount of Pb is 800-1400mg / kg, and the pH value is between 4.9-7.5. The goal of soil remediation is to passivate and stabilize the microcapsule composite material. After the chemical technology, the effective concentration of cadmium and lead in the soil decreased by 30%.

[0119] The present invention provides a kind of microcapsule composite material of Cd, Pb polluted soil, b...

technical field

[0001] The invention relates to the technical field of soil remediation, in particular to a microcapsule composite material for Cd and Pb polluted soil, a preparation method and a remediation method. Background technique

[0002] Cadmium is a dangerous environmental pollution element with only two valence states of 0 and +2. The average content of cadmium in the lithosphere is between 0.1 and 0.2 mg / kg. Cadmium often coexists with zinc and lead in nature, and cadmium in soil only involves divalent cadmium and its compounds. Cadmium is easily absorbed by plants. As long as the cadmium content in the soil increases slightly, the cadmium content in plants will increase accordingly. Cadmium is highly toxic and is chemically close to zinc. Therefore, in some biochemical processes, cadmium can be used as a chemical analogue of zinc to replace zinc, destroying various carbonases, dehydrogenases and phosphatases related to human respiration and digestion. Similarl...

Examples

preparation example Construction

[0077] The invention provides a kind of preparation method of microcapsule composite material, comprising:

[0078] S1, thermally modifying the clay minerals to obtain modified clay minerals;

[0079] The specific preparation method of modified clay mineral includes:

[0080] 1), pretreatment: naturally dry the clay minerals, crush them, and sieve them through a 200-mesh sieve to obtain clay mineral pretreatment products;

[0081] 2), heat treatment: heat-treat the clay mineral pretreated product to obtain a clay mineral heat-treated product; wherein, the heat-treatment temperature is 200°C-600°C, and the heat-treatment time is 5-7 hours;

[0082] 3) Cooling treatment: putting the heat-treated clay mineral product into a drier for cooling to obtain the modified clay mineral.

[0083] S2, prepare calcium magnesium matrix composite material;

[0084] S3. Mixing the modified clay mineral, the calcium-magnesium-based composite material, the sulfate and the pH regulator accordin...

Embodiment 1

[0104] The samples used in the experiment came from Cd and Pb polluted farmland in a certain area of ​​Tianjin, and the total amount of Cd and Pb in the soil samples was detected by the method stipulated in the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard" (GB15618-2018); Determination of mass effective lead and cadmium The method specified in "Atomic Absorption Method" (GB / T23739-2009) detects the effective concentration of Cd and Pb in soil samples. The test results show that the total amount of Cd in the polluted soil of this farmland is 0.8-1.3mg / kg, the total amount of Pb is 934-680mg / kg, and the pH value is between 7.3-7.8. The goal of soil remediation is to passivate and stabilize the microcapsule composite material After the chemical technology, the effective concentration of cadmium and lead in the soil decreased by 30%.

[0105] The present invention provides a kind of microcapsule composite material of Cd, Pb polluted soil, by w...

Embodiment 2

[0118] The samples used in the experiment came from Cd and Pb polluted farmland in a certain area of ​​Shaoxing, and the total amount of Cd and Pb in the soil samples was detected by the method stipulated in the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard" (GB15618-2018); Determination of mass effective lead and cadmium The method specified in "Atomic Absorption Method" (GB / T23739-2009) detects the effective concentration of Cd and Pb in soil samples. The test results show that the total amount of Cd in the polluted soil of this farmland is 1.2-3.5mg / kg, the total amount of Pb is 800-1400mg / kg, and the pH value is between 4.9-7.5. The goal of soil remediation is to passivate and stabilize the microcapsule composite material. After the chemical technology, the effective concentration of cadmium and lead in the soil decreased by 30%.

[0119] The present invention provides a kind of microcapsule composite material of Cd, Pb polluted soil, b...

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