Efficient and Selective Removal of Copper(II) from Aqueous Solution by a Highly Stable Hydrogen-Bonded Metal-Organic Framework

Copper(II) is an indispensable element in nature, while exposure to excessive Cu2+ will potentially cause health issues. It is imperative to develop new strategies for efficient Cu2+ uptake from aqueous solution. Herein, a hydrogen-bonded metal-organic framework (MOF) [(Zn3L3(H2O)(6)][(Na)(NO3)] (1) with high stability was elaborately constructed. The uncoordinated carboxylate oxygen atoms in the channels of MOF were designed as active sites to recognize Cu2+ and further coordinate with it. Without pretreatment, MOF 1 demonstrated a relatively high adsorption capacity (379.13 mg g(-1)), exceeding most C2+ adsorbents. Even with the existence of different metal ions and a high concentration of interfering ions, highly selective adsorption of Cu2+ can be achieved. Moreover, the excellent water stability together with the high removal efficiency in the presence of coexisting ions offers MOF 1 the possibility in practical application. The mechanism for C2+ selective adsorption was systematically investigated by UV-vis, Fourier transform infrared, and fluorescence lifetime techniques, which may originate from the strong interaction between Cu2+ and the carboxylate oxygen atoms. Our work may open an avenue to develop MOFs into adsorbent materials for water pollutants.