Resumo

CASTRO, Camilo et al. EFFECT OF THE CHEMICAL COMPOSITION OF WATER ON ITS PHOTOCATALYTIC DISINFECTION. rev.udcaactual.divulg.cient. [online]. 2011, vol.14, n.1, pp.117-125. ISSN 0123-4226.

The present work aims to identify the influence of the chemical composition of water on bacterial inactivation using a photocatalyst. Several simulated water matrixes were prepared using different concentrations of (HCO₃)^-, Cl^-, (SO₄)^2-, (HPO₄)^2- on individual suspensions and all together, as well as, water from a natural source. A native strain of Escherichia coli was used as a model microorganism, and TiO₂ Degussa P-25 was employed as the photocatalyst. Results show that, in different proportions, the presence of Cl^-, (SO₄)^2- or (HPO₄)^2- increases the disinfection time in the SODIS (solar disinfection) and in photocatalytic processes, proportional to the amount of ion in the reaction. In these three cases, the disinfection time in the presence of the photocatalyst was shorter than without it. (HCO₃)^- also increased the disinfection time in the photocatalytic process, but contrarily, in the SODIS process, the disinfection time decreases with the concentration of this ion. Additionally, it was proven that the effective disinfection time for 24h without bacterial regrowth after irradiation is affected by the presence of these ions, and in most of the reactions, with the photocatalyst the residual effect is greater than the one originated with the SODIS process.

Palavras-chave : Photodisinfection; SODIS; TiO₂; Escherichia coli.

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