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Heavy metals are an important class of technogenic toxicants that pollute rivers and underground water. Here we proposed the use of electrochemical methods using silver (Ag)-gold (Au) alloy nanoparticle (NP)-aptamer-modified glassy carbon electrode (GCE) for the detection of lead ions (Pb 2+). Alloy Ag-Au NPs were electrodeposited on the electrode using the potentiostatic double-pulse method. The NPs were characterized by high-resolution transmission electron microscopy, which revealed that the average NP size was 44 nm. The binding of Pb 2+ induced conformational changes of the aptamer and corresponding modulation of electrochemical signals. As a result, we were able to detect Pb 2+ with a straight slope of 0.01-10 µg/L with limits of detection (LOD) of 0.03 × 10 −2 μg/L for CV, DPV and 0.04 × 10-2 μg/L for EIS. The minimum detectable Pb 2+ concentration was calculated to be 0.8 μM.

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In this study, we have fabricated polyacrylonitrile/montmorillonite (PAN/Mt) nanofibrous nanocomposites with variation in concentration of Mt from 0.25% to 1.00%. The electrospinning process developed PAN/Mt nanofibrous nanocomposites having reduced fiber diameters and high surface roughness as observed in Field emission scanning electron microscopy. The nanocomposite nanofibers were characterized by X‐ray diffraction (XRD) and thermogravimetric analyzer for intercalation and thermal stability respectively. PAN/Mt nanofibrous nanocomposites were tested for their water vapor transmission rate, air permeability, burst strength, and tensile strength. The filtration efficiency of 0.75% PAN/Mt nanofibrous nanocomposite was found to be 98.7% for PM2.5 particles present in air with a pressure drop of 46.8 Pa. The adsorption of copper (II) (Cu (II)) ions using 0.75% PAN/Mt nanofibrous nanocomposites has also been studied. The effect of contact time and initial concentration of adsorbent on the adsorption of Cu (II) ions have been analyzed. It was found that the PAN/Mt nanofibrous membranes follows pseudo‐second‐order kinetic model and Langmuir adsorption isotherm for the adsorption of Cu (II) ions from aqueous solutions. This study suggests the potential implication of PAN/Mt nanofibrous nanocomposites for filtration of PM2.5 and adsorption of metal ions.