The competitive effect for the oxidative species produced during solar photo-Fenton process at neutralpH between an organic compound (resorcinol) and a model microorganism (Enterococcus faecalis) wasinvestigated. With this purpose, the inactivation of E. faecalis was evaluated under several solar processes,i.e. SODIS, solar-UVA with H2O2 (10, 20 and 50 mg L−1) and solar-UVA-Fe2+ (2.5, 5 and 20 mg L−1)in the absence and presence of resorcinol (10 mg L−1). The effect of resorcinol on the Fenton reaction(H2O2/Fe2+ in the dark: 5/2.5 and 50/20 mg L−1) efficacy at neutral pH was also evaluated. In spite ofresorcinol maintained a high amount of iron (around 10 mg L−1) in solution during the experiments, withthe highest concentrations of H2O2/Fe2+ (50/20 mg L−1), only a 2-log decrease of bacteria was observedwith 10 mg L−1 of resorcinol, while a 3.5-log abatement was detected without resorcinol. These resultshighlight the competitive role of organic matter for the oxidant species against bacteria when photooxidationand photo-disinfection processes are occurring at the same time. This competition for theoxidant species, mainly hydroxyl radicals generated during photo-Fenton, was confirmed by (i) thesolar photo-Fenton assays at three different concentrations (H2O2/Fe2+): 5/2.5, 10/5 and 20/10 mg L−1,although at elevated concentrations of H2O2 and Fe2+ (50/20 mg L−1) the disinfection efficiency wasindependent of the addition of resorcinol because an excess of radicals were generated, and (ii) bythe photo-Fenton results obtained when the concentration of resorcinol was increased from 20, 30 till40 mg L−1.
- Enterococcus faecalis
- Solar photo-Fenton
- Hydroxyl radicals
Ortega-Gómez, E., Ballesteros Martín, M. M., Esteban García, B., Sánchez Pérez, J. A., & Fernandez-Ibanez, P. (2013). Solar photo-Fenton for water disinfection: An investigation of the competitive role of model organic matter for oxidative species. Applied Catalysis B: Environmental, 148-14, 484-489. https://doi.org/10.1016/j.apcatb.2013.09.051