Environment Research Institute, Shandong University, Qingdao 266237, China.
State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
Molecules. 2022 Apr 8;27(8):2407. doi: 10.3390/molecules27082407.
Heavy metals are non-biodegradable and carcinogenic pollutants with great bio-accumulation potential. Their ubiquitous occurrence in water and soils has caused serious environmental concerns. Effective strategies that can eliminate the heavy metal pollution are urgently needed. Here the adsorption potential of seven heavy metal cations (Cd2+, Cu2+, Fe3+, Hg2+, Mn2+, Ni2+ and Zn2+) with 20 amino acids was systematically investigated with Density Functional Theory method. The binding energies calculated at B3LYP-D3/def2TZVP level showed that the contribution order of amino acid side chains to the binding affinity was carboxyl > benzene ring > hydroxyl > sulfhydryl > amino group. The affinity order was inversely proportional to the radius and charge transfer of heavy metal cations, approximately following the order of: Ni2+ > Fe3+ > Cu2+ > Hg2+ > Zn2+ > Cd2+ > Mn2+. Compared to the gas-phase in other researches, the water environment has a significant influence on structures and binding energies of the heavy metal and amino acid binary complexes. Collectively, the present results will provide a basis for the design of a chelating agent (e.g., adding carboxyl or a benzene ring) to effectively remove heavy metals from the environment.
重金属是具有高生物累积潜力的不可生物降解和致癌污染物。它们在水和土壤中的普遍存在引起了严重的环境问题。迫切需要能够消除重金属污染的有效策略。在这里，我们系统地用密度泛函理论方法研究了 20 种氨基酸对 7 种重金属阳离子（Cd2+、Cu2+、Fe3+、Hg2+、Mn2+、Ni2+和 Zn2+）的吸附潜力。在 B3LYP-D3/def2TZVP 水平计算的结合能表明，氨基酸侧链对结合亲和力的贡献顺序为羧基＞苯环＞羟基＞巯基＞氨基。亲和力顺序与重金属阳离子的半径和电荷转移成反比，大致遵循以下顺序：Ni2+＞Fe3+＞Cu2+＞Hg2+＞Zn2+＞Cd2+＞Mn2+。与其他研究中的气相相比，水环境对重金属和氨基酸二元配合物的结构和结合能有显著影响。总的来说，本研究结果将为设计螯合剂（例如添加羧基或苯环）以有效去除环境中的重金属提供依据。
