Composite passivant for soil polluted by heavy metal and preparation method

Abstract

The invention discloses a composite passivant for soil polluted by heavy metal and a preparation method thereof. The composite passivant is prepared by three raw materials of power plant slags, sepiolite mineral powder and calcined lime in proportion. The preparation method comprises the following steps: A. preparing the power plant slags; B. preparing the sepiolite mineral powder preparation; and C. evenly mixing the raw materials prepared by steps A and B with the calcined lime, wherein the mixture is the composite passivant. By utilizing the composite passivant, the contents of the effective constituents, such as silicon oxide, magnesium oxide, calcium oxide, ferric oxide and the like lowering the soil heavy metal activity is 78.2-90.6% which is calculated by the sum of SiO2, MgO, CaO, MnO2 and Fe2O3; the composite passivant can be widely used in various soils polluted by the heavy metal, especially the soil with visco-weight texture; and by using the composite passivant, the contents of cadmium and lead in a soil active state in the pollutant farmland are lowered by 15.9-48.4% and 26.2-56.4% respectively; the contents of the cadmium and the lead of agricultural products are lowered by 13.6-43.9% and 22.1-53.2% respectively; and the soil pH value is also improved by 0.21-0.46%. The composite passivant has various functions of passivating soil heavy metal, repairing acidification soil and improving the soil tilth and the like.

Description

technical field [0001] The invention belongs to the technical field of agricultural environment conservation and restoration, and more specifically relates to a compound passivator for heavy metals in polluted soil, and also relates to a preparation method for a compound passivator for heavy metals in polluted soil, which is suitable for various heavy metals Contaminated soils, especially those with a heavy texture. Background technique [0002] With the continuous advancement of industrialization and urbanization, the problem of heavy metal pollution in my country's soil has been paid more and more attention by people. According to relevant reports, in the early 1980s, the area of ​​cultivated land polluted by heavy metals such as cadmium, lead, mercury, arsenic, chromium, and nickel in my country was only 2.67 million hm 2 , increased to 6.67 million hm in 1988 2 , had exceeded 10 million hm by the end of the last century 2 , has exceeded 20 million hm 2 , accounting f...

AI Technical Summary

Problems solved by technology

Most of the research results show that the application of lime-like substances is an effective measure to reduce soil cadmium bioavailability and reduce plant uptake, but the effect varies greatly under different soil conditions, types of lime-like substances, dosage and management conditions (Hong et al. , 2007; Tsadilase et al., 2005; Huo Wenrui et al., 1989; Cao Renlin et al., 1992; Tu Naimei et al., 2000; Liao Min et al., 1998)

The research results of Cao Renlin et al. (1992) and Huo Wenrui et al. (1992) showed that on acidic paddy soil, the application of lime can significantly promote the growth and yield of rice and reduce the cadmium content of rice; growth, reduce the yield of rice, and the effect of reducing the cadmium content of rice is very unstable, and even the cadmium content of rice treated with lime is higher than that of the control

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