Synthesis of an anionic 2D → 3D interpenetration metal–organic framework for efficient removal of Sr2+

Abstract

Rapid removal of radioactive strontium from solutions is of great significance for ecosystem conservation. Herein, a new Cu-Zn-MOF namely, [NH4]3[(Cu3Zn2(FDA)6(H2O)8Cl·3H2O] (Cu-Zn-MOF; H2FDA = 2,5-furandicarboxylic acid) is designed for the efficient adsorption of radioactive Sr2+ by ion exchange. The newly designed Cu-Zn-MOF possessed an anionic 2D → 3D interpenetration framework based trinuclear centers which are charge-balanced by amino cations. Kinetic studies showed that Cu-Zn-MOF rapidly removed Sr2+ (96.7 % in 4 h), and the kinetic data fitted well with the pseudo-second-order model. The adsorption isotherms were well described by Langmuir model and Cu-Zn-MOF exhibited high adsorption capacity (220.7 mg/g at 298 K), out-performing many state of the art adsorbents. More importantly, Cu-Zn-MOF exhibited intriguingly high selectivity for Sr2+ in solutions containing coexisting ions with good reusability. The findings of this study can provide key and useful information for the adsorptive removal of Sr2+ and other similar radioactive material with minimal processing and cost.