Application of potassium calcium magnesium sulfate as repairing material in reduction of bioavailability of Cd in alkalescent soil

Abstract

The invention provides application of potassium calcium magnesium sulfate as a repairing material in reduction of the bioavailability of Cd in alkalescent soil, and relates to the technical field of soil heavy metal pollution prevention and control. Potassium calcium magnesium sulfate is a natural fertilizer, sulfate radicals contained in the potassium calcium magnesium sulfate and ammonium ions in the alkalescent soil can form strong acid and alkalescent salt, H < + > generated after hydrolysis can reduce the pH of the alkalescent soil, and the situation that the alkalinity of the soil is too high is avoided; calcium oxide and magnesium oxide in potassium calcium magnesium sulfate can form a stable structure with Cd, so that the proportion of residual Cd in soil is increased, and the bioavailability of Cd is reduced; the potassium calcium magnesium sulfate can provide potassium, calcium, magnesium, sulfur and other nutrients necessary for crop growth, improve soil fertility, and improve the agglomeration ability of soil particles and the buffer ability of soil after being applied to the soil, thereby improving the soil moisture value and the tilling adaptability of the soil. The potassium calcium magnesium sulfate is used as a repairing material to be applied to the alkalescent soil, so that the bioavailability of heavy metal Cd in the alkalescent soil can be effectively reduced, and the soil fertility can be improved.

Description

technical field [0001] The invention relates to the technical field of prevention and control of soil heavy metal pollution, in particular to the application of potassium calcium magnesium sulfate as a repair material in reducing the bioavailability of Cd in weakly alkaline soil. Background technique [0002] In recent years, heavy metal pollution in cultivated land soil in my country has become more and more serious, and the primary pollutant is heavy metal Cd. Cd is a non-essential element for organisms, and it is considered as the most toxic heavy metal due to its high mobility, high toxicity, high accumulation and difficult elimination. [0003] For large areas of heavy metal-contaminated soil, especially moderately and slightly polluted farmland soil, the in-situ chemical passivation remediation technology has the advantages of simple implementation, low cost and fast treatment speed. For the in-situ fixed passivation restoration of soil Cd pollution, currently widely ...

AI Technical Summary

Problems solved by technology

However, these remediation materials are usually used to remediate Cd pollution in acidic soils, and their main function is to increase the soil pH, which reduces the activity of heavy metals by increasing the soil pH, thereby reducing the bioavailability of heavy metals.

For weakly alkaline soils (pH 7.1 to 7.5), the background pH of the soil is relatively high. If alkaline materials such as phospholime or lime are added, because these materials can greatly increase the pH of the soil, it will make the The pH value of the soil increases to above 7.5, which leads to the strong alkalinity of the soil and increases the risk of soil compaction and soil salinization. At present, there is almost no long-term effective reason for the long-term reduction of soil Cd bioavailability in weakly alkaline soil contaminated by Cd. Bit fixed passivation repair method

In addition, these passivating restoration materials tend to reduce soil fertility

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