2024.01.22《Nanoscale Insights into the Interaction Mechanism Underlying the Adsorption and Retention of Heavy Metal Ions by Humic Acid》
在发表于《EST》的研究中，围绕天然有机质与重金属相互作用的分子机制开展系统探究。依托原子力显微镜，首次在微观尺度上定量表征了腐殖酸与典型重金属离子（如 Cd(II)、Pb(II)、砷酸盐及铬酸盐）之间的相互作用力，并结合耗散型石英晶体微天平、光谱分析及理论计算等多源手段，协同揭示了有机质-重金属间的作用机理。研究表明，腐殖酸与阴、阳离子型重金属的结合模式存在显著差异：对于阳离子重金属（如 Pb²⁺、Cd²⁺），其主要通过与腐殖酸中含氧官能团形成稳定的配位络合，同时还能与芳香结构单元发生阳离子–π相互作用，共同驱动形成稳定的“HA–重金属”桥连结构，从而诱导显著的吸附与团聚效应；而对于阴离子重金属（如 As(V)、Cr(VI)），其与腐殖酸的结合则主要依赖氢键等相对微弱的物理作用，由于缺乏关键的电子轨道重叠与定向化学键合作用，导致其吸附能力明显偏弱。该研究从微观层面为理解重金属离子的环境行为提供了新的机理认知与研究视角。
该文的第一作者为：王周杰；通讯作者：谢磊教授和曾宏波教授
In the study published in EST, a systematic investigation was conducted into the molecular mechanisms underlying the interactions between natural organic matter and heavy metals. Utilizing atomic force microscopy, the interaction forces between humic acid and typical heavy metal ions (such as Cd(II), Pb(II), arsenate, and chromate) were quantitatively characterized at the microscopic scale for the first time. Combined with complementary approaches including quartz crystal microbalance with dissipation monitoring, spectroscopic analysis, and theoretical calculations, the mechanisms governing organic matter–heavy metal interactions were collaboratively elucidated. The research revealed significant differences in the binding modes between humic acid and cationic versus anionic heavy metals: For cationic heavy metals (e.g., Pb²⁺, Cd²⁺), stable coordination complexes are primarily formed through oxygen-containing functional groups in humic acid, accompanied by cation–π interactions with aromatic structural units. These interactions collectively drive the formation of stable "HA–heavy metal" bridged structures, leading to significant adsorption and aggregation effects. In contrast, the binding of anionic heavy metals (e.g., As(V), Cr(VI)) with humic acid relies mainly on relatively weak physical interactions such as hydrogen bonding. Due to the lack of key electron orbital overlap and directional chemical bonding, their adsorption capacity is notably weaker. This study provides new mechanistic insights and research perspectives for understanding the environmental behavior of heavy metal ions at the microscopic level.
First Author: Zhoujie Wang
Corresponding Author: Professor Lei Xie and Professor Hongbo Zeng