Necklace-like Core-shell Structural Mesoporous Silica-coated Nanoscale Zero-valent Iron for Efficient Remediation Cd-Contaminated Water and Soil

The removal of Cd from irrigation water and the remediation of Cd-contaminated soil remain significant challenges. Herein, we developed necklace-like core-shell structured mesoporous silica-coated nanoscale zero-valent iron (NL-NZVI@mHs) to efficiently remediate Cd-contaminated water and soil. The obtained materials had a large specific surface area and a higher adsorption capacity of 41.38 mg/g on Cd(II) [this was 5.7 times for nano-zero-valent iron (NZVI) alone]. X-ray photoelectron spectroscopy demonstrated that ligand exchange, surface complexation, and electrostatic adsorption were the main mechanisms of Cd(II) adsorption. In addition, NL-NZVI@mHs exhibited good performance in the removal of Cd(II) from practical irrigation water samples. The nanochain mesoporous term chain of zero-valent iron exhibits long-term stability, indicating that it can be used multiple times (reduce waste volume). Furthermore, the addition of the obtained NL-NZVI@mHs composites decreased the bioavailability of Cd in the soil and significantly reduced the Cd content in rice seedlings. The results of this study provide a promising strategy for the remediation of Cd-polluted water and soil that may have large-scale applications in the future. Graphical abstract