Strip‐based nano‐silver biocomposite construct for rapid screening of aqueous mercury

A simple, rapid and a cost‐effective colorimetric method for detection of Hg ²⁺ in an aqueous system using silver nanoparticle (AgNP) has been developed in the present study. AgNPs were synthesised using gum kondagogu (GK), a natural biopolymer that acts as both reducing and stabilising agent. The stability of GK‐AgNPs composites was determined by zeta potential and was observed to be −30.43 mV. The yellow colour spot on the nitrocellulose membrane turned colourless at Hg ²⁺ concentration of 20 ppm in aqueous solution, which can be observed visually. By using inductively coupled plasma mass spectrometry, it was observed that as the concentration of Hg ²⁺ increases the Ag concentration decreased. Further, scanning electron microscopy and energy‐dispersive X‐ray spectroscopy were used to confirm the morphological changes on membrane before and after treating with Hg ^{2 +} . The interference of other metal ions was also studied to validate Hg ²⁺ specificity. This method was successfully employed to screen Hg ²⁺ in industrial effluents. In summary, this study entails the development of a nitrocellulose membrane based mercury sensor that has practical applicability for on‐site screening of Hg ²⁺ contamination in the aqueous system.