Fast and Selective Detection of Cr(III) in Environmental Water Samples Using Phosphovanadate Y(V0.2P0.8O4):Eu3+ Fluorescence Nanorods

Phosphovanadate Y(V0.2P0.8O4):Eu3+ nanorods have been created via a simple hydrothermal method and used for the highly sensitive and selective fluorescence detection of Cr3+ over other common heavy metal ions within a 10 min period. It was found that the fluorescence intensity of Y(V0.2P0.8O4):Eu3+ linearly decreases with Cr3+ concentrations ranging from 1 × 10–9 to 1.2 × 10–6 M. The sensing mechanism for Cr3+ is ascribed to the aggregation of Y(V0.2P0.8O4):Eu3+ nanorods triggered by Cr3+ ions owing to the high affinity of phosphate groups to metal ions. The excellent chemical stability, photostability over a wide pH range of 3–12, and high salt-tolerance performance with ionic strength from 1× 10–3 to 12 M of Y(V0.2P0.8O4):Eu3+ allow these nanorods to successfully overcome the photobleaching and pH-dependent fluorescence property of traditional organic fluorescence probes. These characteristics ensure their applicability to environmental monitoring of Cr3+. The sensitive determination of Cr3+ in different environmental water samples demonstrated the potential application of Y(V0.2P0.8O4):Eu3+ as a practical environmental probe. With the help of a UV lamp (254 nm), the visual Cr3+ values for dynamic monitoring in industrial wastewater further verified that this method can even exhibit on-site visible features in daytime and night easily. This allows for the direct monitoring of environmental Cr3+.