Application of a tailor-made polymer as a selective and sensitive colorimetric sensor for reliable detection of trace levels of uranyl ions in complex matrices

Abstract

In this study, a new colorimetric chemosensor based on ion imprinted polymer nanoparticles was designed for quantitative detection of uranyl ions at trace levels in environmental water samples. The removal and pre-concentration of uranyl ions using the synthesized imprinted polymer was performed under optimized conditions and the color of the sorbent changed from yellow to violet. UO₂²⁺-imprinted polymer nanoparticles were synthesized by a precipitation polymerization technique. The sorbent was characterized using solid state UV-vis analysis, thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscopy (SEM), elemental analysis (CHN) and Fourier transform infrared spectrometry (FT-IR). The color change provides a simple, rapid and reliable method for the sensitive and selective visual detection of trace levels of uranyl ions without the need of sophisticated instruments. The color of the sorbent in the absence and presence of uranyl ions shifts from yellow to violet. The method detection limit of the synthesized chemo-sensor for uranyl ions was 0.0005 ppm. The method was successfully applied for trace detection of uranyl ions in distilled, tap, Caspian Sea and Persian Gulf water samples.