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...

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Problems solved by technology

[0035] 1. Engineering restoration: If the foreign soil method is adopted, a large amount of foreign soil needs to be taken, and the same amount of contaminated soil needs to be disposed of;

[0036] 2. Physical and chemical treatment: serious damage to soil structure and soil fertility, complicated process control, high treatment unit cost, poor technical stability, and large disturbance to soil

[0038] 4. Bioremediation: The treatment cycle is long, the later plant collection and treatment process is more complicated, and the maintenance management cycle is long

[0039] 5. Constructed wetland: The treatment cycle is long, the plant activity decreases in winter, and the adsorption capacity of heavy metals decreases; the project covers a large area

[0040] 6. Permeable reaction wall: the construction cost is high, and the seasonal change of groundwater affects the treatment effect

There is no direct effect on soil remediation without leaching

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