First-principles study on the stability of Cd passivates in soil

Abstract

The stable existence of heavy metals in soil under natural conditions is the core issue in heavy metal pollution solidification and remediation technology. This paper takes the common heavy metal ion Cd2+ as an example to analyze the stability of the combination of heavy metal ions and common ion groups in soil. The stability and existing form of Cd are analyzed by using the first principle, and the free energy, band structure, and partical density of states (PDOS) of CdCO3, CdSO4, CdCl2, CdSiO3 are calculated. Determine the stability of Cd binding to common anions in soil. The results show that the order of structural stability of cadmium compounds from high to low is CdSiO3, CdSO4, CdCO3, CdCl2. SO42−, and SiO32− can be used as preferred functional groups for cadmium pollution passivation. Anhydrous sodium sulfate and sodium silicate are effective passivator.