Abstract

Layered double hydroxides (LDHs) and LDHs-derived materials are emerging as potential engineered adsorbents for the protection of water environment. Particularly, LDHs intercalated with different guest compounds (GC-LDHs), which differ from traditional interlayer anions (such as Cl⁻, SO₄²⁻, NO₃⁻, CO₃²⁻, and PO₄³⁻), are widely reported by recent studies showing their promising multifunctional roles in water purification. Herein, this review systematically presents the synthesis methods and characterization techniques of GC-LDHs and their application as adsorbents in removing potentially toxic elements (PTEs) from the aqueous phase. This review also elaborates on the important roles of complexation, chelation, precipitation, isomorphic substitution, and ion exchange in the process of PTE removal by GC-LDHs. Among them, compared with PTE cations, ion exchange is an additional mechanism for the removal of PTE oxyanions by GC-LDHs. Furthermore, the influence of pH, ionic strength, temperature, physiochemical properties of original LDHs and guest compounds on the GC-LDHs adsorption performance are also summarized. Finally, the development trends and future challenges related to GC-LDHs are proposed.

摘要

层状双氢氧化物 (LDHs) 和 LDHs 衍生材料正在成为保护水环境的潜在工程吸附剂。特别是，LDHs 嵌入了不同的客体化合物 (GC-LDHs)，不同于传统的层间阴离子（如 Cl ^-、SO ₄ ^2-、NO ₃ ^-、CO ₃ ^2-和 PO ₄ ^3-), 被最近的研究广泛报道，显示出它们在水净化中有前途的多功能作用。在此，这篇综述系统地介绍了 GC-LDHs 的合成方法和表征技术及其作为吸附剂从水相中去除潜在毒性元素 (PTE) 的应用。该综述还阐述了络合、螯合、沉淀、同构取代和离子交换在 GC-LDHs 去除 PTE 过程中的重要作用。其中，与PTE阳离子相比，离子交换是GC-LDHs去除PTE氧阴离子的额外机制。此外，还总结了pH、离子强度、温度、原始LDHs和客体化合物的理化性质对GC-LDHs吸附性能的影响。最后，