Solvothermal synthesis of KBi3F10:Eu3+ phosphors as selective three-in-one fluorescent probes for Cr3+, CrO42− and Cr2O72− ion detection

Abstract

Chromium is a common heavy metal element that is harmful to the ecosystem as well as human health, so sensitive detection of chromium ions in solution is important for life and health. In this paper, a series of Eu³⁺-doped KBi₃F₁₀ fluorescent powders were successfully synthesized by a one-step solvothermal method for the selective detection of Cr³⁺, CrO₄²⁻ and Cr₂O₇²⁻ ions in an aqueous solution. When adjusting the pH value to 3 and adding PVP as an additive, the obtained KBi₃F₁₀:12%Eu³⁺ phosphor showed excellent red luminescence. Due to the competitive absorption and the inner filter effect of Cr³⁺, CrO₄²⁻ and Cr₂O₇²⁻ ions, the red emission from Eu³⁺ ions produces fluorescence quenching, which can be used to detect them with good selectivity. And the detection limits are as low as 0.19 μM, 0.38 μM and 0.094 μM for Cr³⁺, CrO₄²⁻ and Cr₂O₇²⁻ ions, respectively. Other metal ions and common anions showed little interference with chromium ion detection. The obtained fluorescent probe has good recyclability, accurate and reliable detection results, simple operation and low cost and is easy to promote, which make it an excellent three-in-one probe for chromium detection.