Colorimetric and plasmonic detection of Hg2+ in water by biogenic Ag nanoparticles synthesized with Opuntia joconostle

Abstract

Silver nanoparticles (AgNPs) have been synthesized, for the first time, using the pulp of Opuntia joconostle fruit as reducing reagent of Ag+ ions. The reported method is wholly green, since no temperature or infusion preparation were required. AgNPs with a 428 nm plasmon absorbance, a quasi-spherical morphology, a mean size of 17.7 nm, and an FCC crystal structure were obtained. These biogenic AgNPs, without further chemical functionalization, could sense easily (naked eye) and selectively the presence of Hg2+ ions in aqueous solution and in tap water.