Ultrafast and Selective Adsorption of 99 TcO 4 – /ReO 4 – from Water by Nonporous Cationic Metal–Organic Framework

Rationally designing adsorbents for the effective and selective removal of 99 TcO 4 – from a water environment is extremely desired but remains a challenge. In this study, we successfully constructed a nonporous cationic metal–organic framework (MOF-1) with a three-dimensional architecture. Remarkably, nonporous MOF-1 exhibits extremely fast adsorption kinetics toward ReO 4 – (a nonradioactive analog for 99 TcO 4 – ), achieving adsorption equilibrium within 1 min. And the maximum adsorption capacity of MOF-1 for ReO 4 – is 375 mg/g. Furthermore, MOF-1 exhibits exceptional selectivity for ReO 4 – removal in the presence of large excesses of competing anions such as NO 3 –, SO 4 2–, and Cl –, as even 6000 times of SO 4 2– in excess does not significantly affect the sorption of ReO 4 – . Additionally, MOF-1 shows excellent ReO 4 – removal efficiency over a broad pH range (2.0–11.0), and it can still remove 97% of ReO 4 – after four recycles. Furthermore, a combination of characterization analyses, molecular dynamics simulations, and density functional theory calculations is utilized to clearly elucidate the adsorption mechanism of MOF-1 toward 99 TcO 4 – /ReO 4 – . MOF-1 holds superior adsorption performance and significant potential for large-scale preparation and is proven to be a highly promising material for removing 99 Tc from contaminated water sources.