Effect of Fe(II)/Fe(III) species, pH, irradiance and bacterial presence on viral inactivation in wastewater by the photo-Fenton process: Kinetic modeling and mechanistic interpretation

• Published in: Applied catalysis. B, Environmental Environmental, 2017-05, Vol.204, p.156-166
• Main Authors: Giannakis, Stefanos, Liu, Siting, Carratalà, Anna, Rtimi, Sami, Bensimon, Michaël, Pulgarin, César
• Format: Article
• Language: English
• Subjects: Advanced oxidation processes; Bacteria; Catalytic oxidation; Competition; Deactivation; Disinfection & disinfectants; Hydrogen ions; Hydrogen peroxide; Inactivation; Iron; Iron catalysts; Iron compounds; Irradiance; Kinetics; Microorganisms; MS2 Coliphage inactivation; Near-neutral photo-Fenton; Organic matter; Oxidants; Oxidation; Oxidizing agents; pH effects; Reaction kinetics; Reactive oxygen species; Salts; Scavengers; Solubilization; Sunlight; Viral and bacterial disinfection; Viruses; Wastewater; Wastewater treatment; Water treatment
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2016.11.034

[Display omitted] •MS2 coliphage inactivation parameters by the photo-Fenton process in wastewater were assessed.•Dissolved Organic Matter did not inhibit the photocatalytic MS2 inactivation at near-neutral pH.•Increased iron presence by DOM complexation enhanced the inactivation of MS2 virions.•In presence of their bacterial host, the competition for oxidants delayed MS2 inactivation.•An integrated mechanism for the MS2 inactivation in wastewater was proposed. Advanced Oxidation Processes and in particular photo-Fenton, represent promising strategies of pathogen inactivation in wastewater effluents. Nevertheless, its full potential is not yet unlocked, as the efficacy of photo-Fenton against viruses has not been deeply explored. In this work, we characterize the effect of major parameters (Fe species and concentration, solar irradiance, pH and microbial competition) on the inactivation of MS2 Coliphage by the photo-Fenton process. The use of Fe(II) salts, under any combination of H2O2 concentration, sunlight irradiance or starting pH (6–8), induced a faster inactivation compared to their Fe(III) counterparts. Moreover, ICP-MS analyses revealed that starting with Fe(II) resulted to higher amount of iron in solution longer than Fe(III), which led to higher inactivation kinetics. Even so, a 4-log MS2 inactivation was achieved upon exposure to 600W/m2 for 30min in presence of Fe(III) and H2O2 (1:1 ratio). Furthermore, the inactivation of MS2 was only slightly decreased in presence of the bacterial host, suggesting a low competition for the oxidants in the bulk. The enhancement of iron solubilization through its complexation by organic matter present in wastewater was also investigated, observing an efficient viral inactivation despite the presence of reactive oxygen species (ROS) scavengers. The present data have been used to propose a simple model describing MS2 photo-Fenton inactivation in wastewater. Finally, the pathway describing the photo-Fenton-induced MS2 inactivation in wastewater was proposed, in presence or absence of bacteria.