Theory-driven design of cadmium mineralizing layered double hydroxides for environmental remediation

• Published in: Chemical science (Cambridge) Vol. 15; no. 32; pp. 1321 - 1331
• Main Authors: Li, Zixian, Xu, Nuo, Ren, Jing, Hao, Haigang, Gao, Rui, Kong, Xianggui, Yan, Hong, Hua, Xiao, Peng, Yung-Kang, Ma, Shulan, O'Hare, Dermot, Zhao, Yufei
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 14.08.2024; The Royal Society of Chemistry
• Subjects: Calcium ions; Chemistry; Coordination; Density functional theory; Environmental restoration; Heavy metals; Hydroxides; Mineralization; Molecular dynamics; Molecular structure; Remediation; Soil layers; Soil pollution; Soil remediation; Soil water
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d4sc02860k

The environmental concern posed by toxic heavy metal pollution in soil and water has grown. Ca-based layered double hydroxides (LDHs) have shown exceptional efficacy in eliminating heavy metal cations through the formation of super-stable mineralization structures (SSMS). Nevertheless, it is still unclear how the intricate coordination environment of Ca 2+ in Ca-based LDH materials affects the mineralization performance, which hinders the development and application of Ca-based LDH materials as efficient mineralizers. Herein, we discover that, in comparison to a standard LDH, the mineralization efficiency for Cd 2+ ions may be significantly enhanced in the pentacoordinated structure of defect-containing Ca-5-LDH utilizing both density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. Furthermore, the calcination-reconstruction technique can be utilized to successfully produce pentacoordinated Ca-5-LDH. Subsequent investigations verified that Ca-5-LDH exhibited double the mineralization performance (421.5 mg g −1 ) in comparison to the corresponding pristine seven coordinated Ca-7 OH/H 2 O -LDH (191.2 mg g −1 ). The coordination-relative mineralization mechanism of Ca-based LDH was confirmed by both theoretical calculations and experimental results. The understanding of LDH materials and their possible use in environmental remediation are advanced by this research. The environmental concern posed by toxic heavy metal pollution in soil and water has grown.