An ingenious one-dimensional zirconium phosphonate with efficient strontium exchange capability and moderate proton conductivity

Abstract

A new 1-D zirconium phosphonate [(CH₃)₂NH₂]₂[Zr(CH₂(HPO₃)(PO₃))₂] (SZ-5) was synthesized via a solvothermal reaction and its single crystal structure was elucidated. SZ-5 exhibits efficient strontium exchange capability with high uptake capacity and selectivity, as further demonstrated by the radioactive Sr-90 removal from a real contaminated seawater sample with an extremely high ionic strength. In addition, the measured proton conductivity at 90 °C and 90% relative humidity (RH) is 5.65 × 10⁻⁴ S cm⁻¹. The efficient ion-exchange ability and the moderate proton conductivity suggest the potential applications of SZ-5 in fuel cells or in the remediation of contaminated water.