Evaluación de la inhibición bacteriana utilizando un fotocatalizador nanocomposito de dióxido de titanio-magnetita.

Abstract

The inhibitory effectiveness of a photocatayst composite of titanium dioxide-magnetite (TiO2-Fe3O4) was evaluated in water inoculated with S.aureus and E.coli. Three differend formulations of photocatalyst were synthesized by sol-gel method at 1%, 5% and 10% magnetite (Fe3O4). A simple previously inoculated with bacteria was subjected to ultraviolet light (UV) for 30 minutes, adding 0.5 g/L and 1 g/L for S.aureus and 1.5 g/L and 2.5 g/L for E.coli; the effectiveness of the process was evaluated when performing the experimentation without oxygenation and with oxygenation. The best results were obtained on the process that were not subjected to oxygenation, achieving to inhibit the two bacteria at 100%; while its counterpart with oxygenation did not manage to inhibit the bacteria growth in its entirely, obtaining a percentage of inhibition for S.aureus: 95% (0.5 y 1 g/L al 1%), 98% (0.5 g/L al 5%), 97 % (1 g/L al 5%) y 98% (0.5 y 1 g/L al 10%), whereas for E.coli the inhibition percentage was: 98% (1.5 y 2.5 g/L al 1%), 99% (1.5 y 2.5 g/L al 5%), 98% (1.5 g/L al 10%) y 99% (2.5 g/L al 10%). After the end of the experiment the photocatalyst was recovered by using a magnet, recovering an avarage of 83% (0.5 g/L) and 75% (1 g/L) for S.aureus; 73% (1.5 g/L) and 72% (2.5 g/L) for E.coli without oxygenation. Meanwhile for the process with oxygenation an average of 68% (0.5 g/L) and 71% (1 g/L) for S.aureus; 72% (1.5 g/L) and 72% (2.5 g/L) for E.coli was recovered, with the possibility of being reused. It is recommended that the aging time of the gel solution be minimal to avoid excessive growth of the crystals.