Asynchronous Synergetic Remediation Strategy for Cd-Contaminated Soil via Passivation and Phytoremediation Technology

Cadmium (Cd) contamination in soil has emerged as a significant challenge for agricultural production. Phytoremediation and passivation are key techniques for remediating Cd-contaminated soil. However, few studies have focused on the synergistic effects of these two techniques. In this work, the effectiveness of synergetic remediation strategies, both synchronous and asynchronous, utilizing passivation and phytoremediation techniques, was explored. The results of pot experiments and field experiments indicated that optimal remediation effects were obtained by asynchronous synergetic remediation, removing over 80% of bioavailable Cd within 14 days. Mechanistic studies conducted using XPS analysis, soil property analysis, and microbial diversity analysis confirmed that the chelation effect of SDD and soil pH value are the primary factors contributing to the effectiveness of both remediation strategies. In contrast, the variations in microbial populations are identified as the crucial factors influencing the varying outcomes of the two sequential remediation approaches. This research demonstrates that asynchronous synergistic remediation is a promising strategy for mitigating Cd contamination in soil.