One-Pot Detection of Heavy Metals and Biosynthesis of Fluorescent Nanoparticles from Metals in Groundwater Samples

Abstract

Heavy metals like Pb2+ and Hg2+ are well known for their toxicity and harmful health impacts. The present study was designed to carry out on-site detection of heavy metals like Pb2+ and Hg2+ in the water samples passed through the egg shell powder column. Egg shells are washed and powdered, preheated at 110 °C for activation, and used as stationary phase in the column. Two metal solutions of varying concentrations (1 μg·L−1, 10 μg·L−1, 100 μg·L−1, and 1000 μg·L−1) were prepared in different buffers of basic pH (8–11) and then passed through the column, and plain buffer solutions were used as control. The column eluent was observed under a trans-illuminator for fluorescence and checked for absorbance in a UV-visible spectrophotometer from 200 to 600 nm. The presence of fluorescence and UV absorption indicated the presence of heavy metals in the sample. Proteins present in the egg shell, on reacting with metal ions, formed stable nanoparticles due to reduction and capping. The biosynthesized nanoparticles from egg shell proteins were confirmed by SEM analysis, where Pb2+ and Hg2+ nanoparticles were formed. The study was repeated for the detection of heavy metals present in groundwater samples, which was confirmed from fluorescence, UV-visible spectrum, EDAX, and FESEM where heavy metal nanoparticles of size range 12–23 nm were formed. Therefore, this method could be a good alternative for the detection of heavy metals at low concentrations in environmental samples and is feasible for on-site detection.