Construction of dual sulfur sites in metal-organic framework for enhanced mercury(II) removal

Highly efficient removal of mercury ion (Hg²⁺) from aqueous solution is a serious concern. Herein, a novel metal-organic framework (MOF) containing dual sulfur sites was successfully constructed via an in-situ method. Different with previous reports, thiophene and thiol sites were simultaneously introduced via organic linker and inorganic cluster, resulting in high-density sulfur sites. The composition and porosity of the newly synthesized DUT-67-SH (DUT, Dresden University of Technology) were systematically characterized. Based on abundant sulfur sites and strong host-guest interaction, DUT-67-SH exhibits a high adsorption capacity (370.2 mg g^-1) and rapid adsorption kinetics (∼3 min for equilibrium). Excellent separation selectivity, regenerability, and applicability under wide acidic pH range were further confirmed. Mechanism analysis suggests that the chemical bonding between sulfurs and Hg²⁺ is the main driven force. Thus, our work demonstrates that DUT-67-SH is a potential adsorbent for Hg²⁺, and more importantly, provides a new insight for introducing high-density sulfur sites in MOFs.