title: Pyrene photochemical species in commercial clays.
abstract: The photochemistry of pyrene, a polycyclic aromatic hydrocarbon, adsorbed on kaolinite, sodium montmorillonite and acid bentonite K10® was investigated to determine how the concentration and structure of the clay minerals affect the formation of different species of pyrene. Fluorescence emission spectra were obtained using reflection geometry for pyrene at the concentrations ranging from 0.5 to 100.0 μmol g(-1) (pyrene:clay). Two pyrene photochemical species were observed, the monomer, which fluoresces at 396 nm, and its excimer which fluoresces at 470 nm. The formation of excimers occurred first on the kaolinite, due to the smaller surface area. In the acid montmorillonite, the fixed interlamellar space provided greater specific area, leading to lower formation of excimers. Emission from pyrene crystals was also detected for samples with high loadings.
authors.affiliation: Instituto de Química, Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier, 524, Maracanã, 20550-900 Rio de Janeiro, RJ, Brazil.
authors.forename: Silvio Cesar Godinho
authors.initials: SC
authors.lastname: Teixeira
authors.forename: Anabela
authors.initials: A
authors.lastname: Oliveira
authors.forename: Paulo
authors.initials: P
authors.lastname: Duarte
authors.forename: Luis Filipe
authors.initials: LF
authors.lastname: Vieira Ferreira
authors.forename: Josino Costa
authors.initials: JC
authors.lastname: Moreira
authors.forename: Daniel Vidal
authors.initials: DV
authors.lastname: Peréz
authors.forename: Monica Regina da Costa
authors.initials: MR
authors.lastname: Marques
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry*; D001546:Bentonite / Q000737:chemistry; D000077215:Clay; D004784:Environmental Monitoring; D007616:Kaolin / Q000737:chemistry; D055668:Photochemical Processes; D011721:Pyrenes / Q000032:analysis* / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D011721:Pyrenes; D012989:Soil Pollutants; D001546:Bentonite; D007616:Kaolin; D000077215:Clay