Mechanism of Different Passivating Agents on the Solidification of Heavy Metals in Soil

Abstract

Through the mechanism study, it can be seen that the three kinds of passivating agents can increase the soil pH value and cation exchange capacity, which is beneficial to the transformation of heavy metals from ion exchange state to residue state. The addition of organic fertilizer can increase the activities of urease and acid phosphatase, and montmorillonite is beneficial to activate the activity of catalase in the soil. MO treatment can simultaneously increase the activities of the three enzymes and increase the absorption of soil carbon, nitrogen and organic phosphorus. Electron microscope scanning results showed that MO effectively increased the connectivity between soil particles and increased the specific surface area of soil. Therefore, the synergistic effect of MO treatment on the passivation of heavy metals is obvious, and the passivation effect is the best.