title: Photoinactivation of virus on iron-oxide coated sand: enhancing inactivation in sunlit waters.
abstract: Adsorption onto iron oxides can enhance the removal of waterborne viruses in constructed wetlands and soils. If reversible adsorption is not coupled with inactivation, however, infective viruses may be released when changes in solution conditions cause desorption. The goals of this study were to investigate the release of infective bacteriophages MS2 and ΦX174 (two human viral indicators) after adsorption onto an iron oxide coated sand (IOCS), and to promote viral inactivation by exploiting the photoreactive properties of the IOCS. The iron oxide coating greatly enhanced viral adsorption (adsorption densities up to ≈ 10(9) infective viruses/g IOCS) onto the sand, but had no affect on infectivity. Viruses that were adsorbed onto IOCS under control conditions (pH 7.5, 10 mM Tris, 1250 μS/cm) were released into solution in an infective state with increases in pH and humic acid concentrations. The exposure of IOCS-adsorbed MS2 to sunlight irradiation caused significant inactivation via a photocatalytic mechanism in both buffered solutions and in wastewater samples (4.9 log(10) and 3.3 log(10) inactivation after 24-h exposure, respectively). Unlike MS2, ΦX174 inactivation was not enhanced by photocatalysis. In summary, IOCS enhanced the separation of viruses from the water column, and additionally provided a photocatalytic mechanism to promote inactivation of one of the surrogates studied. These qualities make it an attractive option for improving viral control strategies in constructed wetlands.
authors.affiliation: Laboratory of Environmental Chemistry, School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Pecson
authors.forename: Loïc
authors.initials: L
authors.lastname: Decrey
authors.forename: Tamar
authors.initials: T
authors.lastname: Kohn
mesh_terms: D000327:Adsorption / Q000528:radiation effects; D010584:Bacteriophage phi X 174 / Q000528:radiation effects*; D005290:Ferric Compounds / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000528:radiation effects; D017909:Levivirus / Q000528:radiation effects*; D009930:Organic Chemicals / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D012996:Solutions; D013472:Sunlight; D038301:Virus Inactivation / Q000528:radiation effects*; D014865:Waste Disposal, Fluid; D014871:Water Microbiology
chemical_list: D005290:Ferric Compounds; D009930:Organic Chemicals; D012996:Solutions; C000499:ferric oxide; D012822:Silicon Dioxide