A Green, Rapid and Efficient Dual-Sensors for Highly Selective and Sensitive Detection of Cation (Hg2+) and Anion (S2−) Ions Based on CMS/AgNPs Composites

Abstract

Detection of mercury (Hg2+) and sulfide (S2−), universal and well-known toxic ions, is crucial in monitoring several diseases. How to design and fabricate the high-performance sensor for simultaneously and accurately detecting the Hg2+ and S2− is critical. Herein, we proposed a novel and convenient strategy for optical detection of Hg2+ and S2− by employing a carboxymethyl cellulose sodium/silver nanoparticle (CMS/AgNPs) colloidal solution, in which AgNPs were used as monitor for Hg2+ and S2−, and the CMS was utilized as both the stabilizer and the hydrophilic substrate for AgNPs. Well-identifiable peaks for Hg2+ and S2– were obtained in water based on UV–VIS absorption spectra, the absorbance intensity and/or position of nano-silver vary with the addition of Hg2+ cation and S2– anion, accompanying with color change. Impressively, the optimal AgNPs anchored CMS exhibited a high sensitivity and selectivity toward Hg2+ and S2−, the change in absorbance was linear with the concentration of Hg2+ (0–50 μM) and S2− (15–70 μM), and the lowest limits of detection (LOD) were 1.8 × 10−8 M and 2.4 × 10−7 M, respectively. More importantly, owing to the superior properties in testing Hg2+ and S2−, the fabricated sensor was successfully applied for detection of target ions in lake and tap water samples. All these good results implied that the designed strategy and as-designed samples is promising in detecting cation (Hg2+) and anion (S2−) ions and open up new opportunities for selecting other kinds of ions.