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International Journal of Photoenergy
Volume 2018 (2018), Article ID 1862597, 6 pages
https://doi.org/10.1155/2018/1862597
Research Article

1D TiO2 Nanostructures Prepared from Seeds Presenting Tailored TiO2 Crystalline Phases and Their Photocatalytic Activity for Escherichia coli in Water

1Universidad Nacional de Ingeniería, Av. TúpacAmaru s/n, Rimac, Lima, Peru
2Instituto de Física, Universidad Nacional Autónoma de México, 20364 Ciudad de México, Mexico
3Instituto de Investigación e Ingeniería Ambiental, CONICET, Universidad Nacional de San Martín, Campus Miguelete, 25 de Mayo y Francia, 1650 San Martín, Provincia de Buenos Aires, Argentina
4Centro de Microscopias Avanzadas, FCEyN, Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires, Argentina

Correspondence should be addressed to Juan M. Rodriguez; ep.ude.inu@zeugirdorj

Received 23 July 2017; Revised 4 December 2017; Accepted 28 December 2017; Published 2 April 2018

Academic Editor: Joaquim Carneiro

Copyright © 2018 Julieta Cabrera 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.

Abstract

TiO2 nanotubes were synthesized by alkaline hydrothermal treatment of TiO2 nanoparticles with a controlled proportion of anatase and rutile. Tailoring of TiO2 phases was achieved by adjusting the pH and type of acid used in the hydrolysis of titanium isopropoxide (first step in the sol-gel synthesis). The anatase proportion in the precursor nanoparticles was in the 3–100% range. Tube-like nanostructures were obtained with an anatase percentage of 18 or higher while flake-like shapes were obtained when rutile was dominant in the seed. After annealing at 400°C for 2 h, a fraction of nanotubes was conserved in all the samples but, depending on the anatase/rutile ratio in the starting material, spherical and rod-shaped structures were also observed. The photocatalytic activity of 1D nanostructures was evaluated by measuring the deactivation of E. coli in stirred water in the dark and under UV-A/B irradiation. Results show that in addition to the bactericidal activity of TiO2 under UV-A illumination, under dark conditions, the decrease in bacteria viability is ascribed to mechanical stress due to stirring.