Passivator used for in-situ repairing of polluted farmland soil and processing method

Abstract

The invention discloses a passivator used for in-situ repairing of polluted farmland soil. The passivator comprises raw materials including an iron-based compound, lime charcoal and bentonite. The passivator includes, by weight, 8-30 parts of the iron-based compound, 10-30 parts of the lime charcoal and 20-40 parts of the bentonite. The passivator has the beneficial effects that the sources of reagents adopted in the passivator used for repairing arsenic polluted soil are wide, the cost is low, secondary pollution cannot be caused on soil, a synergistic effect is achieved among different materials, the repairing efficiency is high, and the effect is obvious. When in-situ repairing is conducted on the arsenic polluted soil, the surface of the soil is covered with a repairing material, the 0cm-30 cm surface layer of the soil is evenly mixed with the repairing material in a plough manner, water is added for one week of curing, the leaching concentration of the heavy metal arsenic in therepaired farmland soil is detected, the soil is qualified when the leaching concentration is smaller than the III standard of the Quality Standard for Underground Water (GB / T14848-93), and if the leaching concentration cannot reach the standard, the curing time is prolonged.

Description

Technical field [0001] The invention relates to the field of restoration of arsenic-contaminated soil, in particular to a passivator for in-situ restoration of arsenic-contaminated farmland soil. Background technique [0002] Arsenic exists widely in nature, and hundreds of arsenic minerals have been discovered. Elemental arsenic is non-toxic, but arsenic compounds are toxic. Accumulation of arsenic in the body is toxic to the gastrointestinal tract, liver, kidneys, cardiovascular system, nervous system, and respiratory system, and may cause skin cancer. With the mining and smelting of arsenic-containing metal minerals, the combustion of fossil fuels, the use of arsenic-containing chemicals and pesticides, wood preservation, and the discharge and illegal dumping of industrial wastewater, the concentration of arsenic in the soil is increasing day by day, causing worldwide Different degrees of soil arsenic pollution. Due to the complexity of formation, long-term accumulatio...

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Problems solved by technology

[0004] A comprehensive analysis of the above repair technologies shows that engineering measures are easy to operate, but cost high and are only applicable in a small area; agronomic control measures are simple to operate, low in cost, and relatively mature in technology, but the disadvantage is that the repair effect is limited, and they are only suitable for heavy metals in farmland. and mildly polluted remediation, in which the adjustment of planting structure may lead to difficulties for farmers to accept and affect food security, generally only as an auxiliary means; phytoremediation technology is low in cost and environmentally friendly, but due to its small target biomass, remediation It takes a long time and low efficiency, and it is difficult to promote at present; the chemical in-situ passivation method is low in cost and easy to operate. Although it cannot completely remove heavy metals in the soil, it is suitable for a wide range of farmland, and the selection of suitable curing materials is a chemical method. The essential

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