title: Humic-like substances extracted from composts can promote the photodegradation of Irgarol 1051 in solar light.
abstract: Humic-like substances (HLS) were extracted from a mixture of sewage sludges and trimmings (70-30%, w/w) after different times of composting (0, 70 days and 130 days). HLS were analyzed by elemental analysis, UV-visible and fluorescence spectroscopy and also tested for their ability to photosensitize the degradation of Irgarol. The rate of Irgarol photodegradation in artificial solar light was found to be 2.5- to 4.3-fold higher in the presence of HLS than in buffered Milli-Q water. These results were confirmed by experiments in solar light that evidenced the photodegrading properties of HLS in a more striking way. Using 2-propanol as hydroxyl radical scavenger, we could show that hydroxyl radicals contributed to the photosensitized Irgarol degradation for about 25%. The photodegrading activity of HLS, their absorbance and their emissive properties were all found to increase between 0 and 70 days of composting and to remain quite constant between 70 and 130 days. The degree of humification varied in the same way, linking all these properties to the humification process.
authors.affiliation: Laboratoire de Photochimie Moléculaire et Macromoléculaire, UMR CNRS-Université Blaise Pascal 6505, 63177 Aubière Cedex, France.
authors.forename: Amina
authors.initials: A
authors.lastname: Amine-Khodja
authors.forename: Olga
authors.initials: O
authors.lastname: Trubetskaya
authors.forename: Oleg
authors.initials: O
authors.lastname: Trubetskoj
authors.forename: Luciano
authors.initials: L
authors.lastname: Cavani
authors.forename: Claudio
authors.initials: C
authors.lastname: Ciavatta
authors.forename: Ghislain
authors.initials: G
authors.lastname: Guyot
authors.forename: Claire
authors.initials: C
authors.lastname: Richard
mesh_terms: D019840:2-Propanol / Q000737:chemistry; D002244:Carbon / Q000032:analysis; D006540:Herbicides / Q000737:chemistry / Q000528:radiation effects*; D006812:Humic Substances; D006859:Hydrogen / Q000032:analysis; D007700:Kinetics; D009584:Nitrogen / Q000032:analysis; D010782:Photolysis; D012987:Soil; D014227:Triazines / Q000737:chemistry / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D006540:Herbicides; D006812:Humic Substances; D012987:Soil; D014227:Triazines; C103341:irgarol 1051; D002244:Carbon; D006859:Hydrogen; D009584:Nitrogen; D019840:2-Propanol