Development of Highly Efficient Dual Sensor Based on Carbon Dots for Direct Estimation of Iron and Fluoride Ions in Drinking Water

Abstract

The fluorescent nanomaterial carbon dots (CDs) have attracted tremendous attention in the recent times because of their unique physico‐chemical characteristics. Highly fluorescent CDs were prepared through a simple and nontoxic one‐step hydrothermal carbonization of polyvinylpyrrolidone (PVP). The as‐synthesised CDs, without any pre‐treatments or post‐treatments, show high stability over a broad pH range and have an excellent potential in chemical sensing applications. The as‐prepared CDs have been demonstrated to be an excellent nano probe for Fe3+ ions sensing in aqueous media based on the fluorescence quenching with high sensitivity (lower limit of detection ∼ 1 μM) and selectivity towards Fe3+ ions. “Turn off” fluorescence arises due to the formation of CDs‐Fe3+ nanocomposite complex in the solution. The nanocomposite complex forms by the attachment of Fe3+ ions to the surface emissive site of the CDs, resulting in an obvious fluorescence quenching. Here, CDs itself act as a promising nano carrier for loading of Fe3+ ions to form the CDs‐Fe3+ nanocomposite complex in the solution. In addition to all, in this study we are intensely focused to explore the application of CDs‐Fe3+ nanocomposite complex. We have used the CDs‐Fe3+ nanocomposite complex as a novel sensor probe for the detection of F‐ ions in aqueous media based on “Turn on” fluorescence mechanism. “Turn on” fluorescence occurs due to the formation of thermodynamically highly stable [FeF6]3‐ complex and bare CDs in the solution. The developed sensor has high sensitivity (lower limit of detection ∼ 1 μM) and selectivity towards F‐ ions over a wide‐ranging other competing anions. Finally, we successfully demonstrate the real life application of the developed sensor by estimating the trace F‐ ions in the real world drinking water samples.

Greenish‐Yellow Emitting Carbon Dots as ‘On‐Off‐On’ Fluorescent Probe for Selective Determination of Mercury (II) and Sulphide Ions

“…On the other hand, carbon dots as a fluorescent sensor shows high sensitivity, involves effortless procedure and provide rapid results. The mechanism is mainly based on fluorescence turn‐off/on of carbon dots in presence of specific chemical species [16,17] …”

“…The mechanism is mainly based on fluorescence turnoff/on of carbon dots in presence of specific chemical species. [16,17] Recently, Patir et alsynthesised nitrogen doped carbon dots using urea and EDTA as precursors for the determination of mercury and copper ions in aqueous medium based on fluorescence on-off-on mechanism. [18] Similarly, Jiangling and co-workers synthesised fluorescent carbon dots using citric acid and diethylenetriamine to sense mercury and iodide ions based on photo-induced electron transfer process.…”

High Visual Colorimetric Determination of F‐ Ions by Exploiting the Inhibition of Oxidase Mimicking Activity of FeMnO4@GQD Nanocomposite

“…On the other hand, over exposure to fluoride ions in water may cause chronic dental problems and bone diseases. [6][7][8][9] A high dose of fluoride ions shows a detrimental effect on nerve cells of children and lowers the IQ level, which brings attention deficiency, osteosarcoma, and hyperactive disorder. [10][11][12] So, it looks like a double-aged sword, it is beneficial in lower doses, but a high dose of fluoride ions may cause a major problem.…”

Highly Sensitive Optical Sensor for Selective Detection of Fluoride Level in Drinking Water: Methodology to Fabrication of Prototype Device

“…Over the past decades, a great effort has been devoted to the discovery of new analytical methods for the reliable and cost-effective detection of various targeted species, including cations and anions. − Fluoride is one of the essential anions that has drawn much attention due to its vital importance in various environmental and health-care issues. , F – is naturally found in soil and groundwater, but there are several industrial and agricultural activities which are responsible for large scale fluoride contamination in water. Low content of F – plays an important role in treating the osteoporosis and prevent the dental cavities.…”