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Journal of Nanomaterials
Volume 2018, Article ID 7215210, 7 pages
Research Article

Silver Nanoparticles Obtained by Aqueous or Ethanolic Aloe vera Extracts: An Assessment of the Antibacterial Activity and Mercury Removal Capability

1Facultad de Ciencias Básicas, Grupo de Materiales Nanoestructurados y Biomodelación (MATBIOM), Universidad de Medellín, Medellín, Colombia
2Facultad de Ingenierías, Grupo de Investigaciones y Mediciones Ambientales (GEMA), Universidad de Medellín, Medellín, Colombia
3Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Calle 70, No. 52-21, A.A. 1226, Medellín, Colombia

Correspondence should be addressed to Gloria Campillo; oc.ude.medu@ollipmaceg

Received 30 October 2017; Revised 12 January 2018; Accepted 14 February 2018; Published 19 March 2018

Academic Editor: Francesco Ruffino

Copyright © 2018 Ederley Vélez et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Silver nanoparticles (AgNPs) were synthesized by chemical reduction of Ag+ ions (from silver nitrate AgNO3), using aqueous or ethanolic Aloe vera extracts as reducing, stabilizing, and size control agent. The nanoparticles’ sizes were between 2 and 7 nm for ethanolic extract and between 3 and 14 nm for aqueous extract, as measured by High-Resolution Transmission Electron Microscope (HRTEM). The antibacterial activity against a mesophilic microorganism, Kocuria varians, a Gram-positive coccus, was measured by counting bacterial colonies in agar plate for both extracts. We found that 4% effective concentration is the lowest concentration that completely inhibited visible growth. Mercury removal was investigated by Atomic Absorption Spectroscopy (AAS) measurements, where it was shown that it is not necessary to use high concentrations of nanoparticles for effective removal of mercury inasmuch as with a 20% V/V concentration of both extracts; the Hg(II) removal percentage was above 95%. These results show that the mercury remaining unremoved from the different essays is below the level allowed by World Health Organization (WHO) and the Environmental Protection Agency (EPA).