Eu3+ and Tb3+ anchoring a 2D Zr-MOF for highly efficient fluorescence sensing detection towards Cr2O72- ions with high sensitivity, selectivity and anti-interference performances

Identification and detection of low concentration heavy metal Cr(VI) ions is one of the focus in water environment monitoring field. But, development of fluorescent sensing probes with high sensitivity, selectivity and anti-interference capabilities is still challenging. Given that the antenna effect of organic units can induce rare earth ions to emit high purity fluorescence, two novel luminous materials Eu@Zr-MOF and Tb@Zr-MOF were deliberately assembled by anchoring of Eu3+ and Tb3+ on a 2D Zr-MOF. Compared with the weak fluorescence of Zr-MOF, they emit the strong bright red and bright green luminescence signals of immobilized rare earth Eu(III) and Tb(III), respectively. And their luminescent intensity can be well maintained in water for >7 days. Prominently, Eu@Zr-MOF and Tb@Zr-MOF are fully capable of high-efficiency fluorescence quenching recognition and quantitative detection of Cr2O72- ions (from 0 to 280 mu M), by virtue of their respective maximum emission signal at 618 and 546 nm, exhibiting fairly K-SV values of 7.7 x 10(4) and 6.4 x 10(4) M-1, rather low detection limit (DL) values of 6.63 and 4.82 ppb, which are quite impressive performances even compared to other reported MOFs-based photochemical sensors. This study affords a feasible avenue for designing qualified fluorescence sensors to address some intractable environmental problems, i. e. recognition and detection of heavy metal ions from water.