Synthesis and characterization of stearic acid capped silver nanoparticles: pH dependent stabilization and colorimetric detection of Hg(II) in water

¹Department of Chemistry, University of Delhi, Delhi-11007, India

²Department of Chemistry, Deen Dayal Upadhyaya College, University of Delhi, Dwarka, New Delhi 1100078, India

Adv. Mater. Lett., 2018, 9 (1), pp 53-57

DOI: 10.5185/amlett.2018.1756

Publication Date (Web): May 15, 2018

Copyright © IAAM-VBRI Press

E-mail: nnagasti@gmail.com

Abstract

This work reports, synthesis of Ag nanoparticles in aqueous medium, under ambient reaction conditions using stearic acid as capping agent. Ag nanoparticles have been used for colorimetric detection of Hg²⁺ in water. Effect of pH of the medium on size and stabilization of silver nanoparticles has been studied. Synthesized by chemical reduction of AgNO₃ using NaBH₄, Ag nanoparticles were characterised by UV-visible spectroscopy, transmission electron microscopy (TEM), FTIR spectroscopy and TGA techniques. Quenching of intensity along with blue shift of SPR band of Ag nanoparticles is observed due to deposition of Hg layer over Ag nanoparticles. Change in colour of Ag nanoparticles from dark yellow to colourless led to naked eye detection of Hg²⁺ in water. The detection limit of Hg²⁺ in water was found up to 1ppm monitored by colorimetric response of Ag nanoparticles by UV-visible spectrophotometer. A simple and cost-effective process allows quick determination of Hg²⁺ in water.

Keywords

Stearic acid capped Ag nanoparticles, pH-dependent stability, Effect of pH on size, Hg detection.