Anchoring Thiol-Rich Traps in 1D Channel Wall of Metal-Organic Framework for Efficient Removal of Mercury Ions

Metal-organic frameworks (MOFs) attract broad interests in mercury (Hg) ion adsorption field, while unreasonable distribution of active groups commonly restricts their utilization efficiency. In this work, we constructed a new MOF (TYUST-6) with dense thiol-rich traps in the 1D pore wall. This accessible channel and rational distribution of thiols allow the smooth diffusion of Hg ions and thereby result in a high Langmuir adsorption capacity of 1347.6 mg/g, almost reaching the theoretical maximum (1444.3 mg/g). Adsorption equilibrium needs 10 and 30 min at the initial concentrations of 10 and 100 mg/L, respectively. Common co-existing ions and solution pH show almost negligible interferences on the adsorption, and adsorbent regeneration can be well achieved. Combining experimental characterizations and theoretical calculations, the thiol groups in the pore wall are proved to be the dominant interaction sites. Thus, this work reports a novel high-capacity adsorbent for Hg2+, and proposes a feasible guideline for designing effective adsorbents.