A slow-release remediation agent for treating cadmium-arsenic composite polluted paddy field soil and its preparation method

Abstract

The invention discloses a slow-release restorative agent for treating cadmium-arsenic compound polluted rice field soil and a preparation method thereof. The preparation method comprises the following steps: (1) fully stirring and mixing calcium carbonate and calcium-magnesium phosphate fertilizer, and carrying out the preparation under nitrogen protection. Calcination, the calcined mixture is ground and pulverized to obtain compound A; (2) Add potassium silicate to water and stir to dissolve it, spray the dissolved potassium silicate solution evenly on the surface of iron powder, and then Granulation on the granulator to obtain the mixture granules B; (3) Put the compound A and the mixture granules B in the granulator, and gradually spray pure water until the compound A is evenly wrapped on the surface of the mixture granules B, forming a 3-5 mm diameter Granular matter; (4) drying the granular matter obtained in step (3) to a moisture content of ≤5% to obtain a slow-release restoration agent. The slow-release restorative agent of the present invention can implement synchronous passivation resistance and control of cadmium and arsenic in the key growth period of rice, with small dosage, effectively reduces the content of cadmium and arsenic in rice, and has remarkable and stable effect.

Description

technical field [0001] The invention belongs to the technical field of soil remediation, and in particular relates to a slow-release remediation agent for treating cadmium-arsenic composite polluted paddy field soil and a preparation method thereof. Background technique [0002] Cultivated land soil is the basic condition for agricultural production and cultivation. The health status and nutrient content in the soil directly affect the growth of crops. At present, with the rapid development of industry and agriculture, a large number of pollutants, especially heavy metals, enter the soil environment, resulting in increasingly serious soil pollution. At the same time, the excessive use of agricultural inputs is also one of the important factors causing soil heavy metal pollution. Cadmium and arsenic are common polluting elements in cultivated soil. According to the 2014 National Soil Environmental Survey Bulletin, the point-exceeding rates of cadmium and arsenic in the nati...

AI Technical Summary

Problems solved by technology

Due to the differences in properties and forms of cadmium and arsenic in the soil, the current passivators for treating cadmium-contaminated soils are often not suitable for the treatment of arsenic-contaminated soils, and the passivators for treating arsenic-contaminated soils are also not suitable for cadmium-contaminated soils governance

For example, at present, a large number of alkaline materials are used to repair cadmium-contaminated soil, which is used to increase the pH value of the soil, make the cadmium form hydroxide precipitation, and achieve the purpose of reducing the availability of cadmium in the soil; However, the arsenic in the soil plays an activation role and improves the availability of arsenic in the soil, which is not suitable for the remediation and treatment of arsenic-contaminated soil.

Obviously, it is more difficult to simultaneously remediate cadmium-arsenic compound polluted soil than single cadmium or arsenic pollution

[0004] Due to the differences in the properties and forms of cadmium and arsenic in the soil, it is difficult for the currently commonly used passivation materials to achieve simultaneous passivation of cadmium and arsenic, and it is difficult to simultaneously reduce the content of cadmium and arsenic in rice.

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