Artículo
Photodegradation routes of the herbicide bromoxynil in solution and sorbed on silica nanoparticles
Escalada, Juan Pablo
; Arce, Valeria Beatriz; Carlos, Luciano
; Porcal, Gabriela Valeria
; Biasutti, Maria Alicia
; Criado, Susana Noemi
; Garcia, Norman Andino
; Martire, Daniel Osvaldo






Fecha de publicación:
04/2014
Editorial:
Royal Society of Chemistry
Revista:
Energy & Environmental Science
ISSN:
1754-5692
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Some organic contaminants dissolved in natural waters tend to adsorb on suspended particles and sediments. In order to mimic the photodegradation routes in natural waters of bromoxynil (BXN) adsorbed on silica, we here prepare and characterize silica nanoparticles modified with BXN (NP-BXN). We measure the direct photolysis quantum yield of aqueous BXN at 307 nm (0.064 ± 0.001) and detect the formation of bromide ions as a reaction product. Under similar conditions the photolysis quantum yield of BXN bonded to NP-BXN is much lower (0.0021 ± 0.0004) and does not lead to formation of bromide ions. The rate constant of the reaction of NP-BXN with the excited triplet states of riboflavin, a molecule employed as a proxy of chromophore dissolved organic matter (DOM) was measured in laser flash-photolysis experiments. The rate constants for the overall (kt) and chemical interaction (kr) of singlet oxygen with NP-BXN were also measured. Kinetic computer simulations show that the relevance of the direct and indirect (through reactions with reactive species generated in photoinduced processes) photodegradation routes of BXN is very much affected by sorption on silica. Immobilization of the herbicide on the particles, on one hand, affects the photolysis mechanism and lowers its photolysis quantum yield. On the other hand, the results obtained in aqueous suspensions indicate that immobilization also lowers the rate of collisional encounter, which affects the quenching rate constants of excited triplet states and singlet oxygen with the herbicide.
Palabras clave:
Bromoxynil
,
Photodegradation
,
Silica Particles
,
Nanoparticles
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(CCT - CORDOBA)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - CORDOBA
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - CORDOBA
Articulos(INIFTA)
Articulos de INST.DE INV.FISICOQUIMICAS TEORICAS Y APLIC.
Articulos de INST.DE INV.FISICOQUIMICAS TEORICAS Y APLIC.
Articulos(SEDE CENTRAL)
Articulos de SEDE CENTRAL
Articulos de SEDE CENTRAL
Citación
Escalada, Juan Pablo; Arce, Valeria Beatriz; Carlos, Luciano; Porcal, Gabriela Valeria; Biasutti, Maria Alicia; et al.; Photodegradation routes of the herbicide bromoxynil in solution and sorbed on silica nanoparticles; Royal Society of Chemistry; Energy & Environmental Science; 16; 4; 4-2014; 858-865
Compartir
Altmétricas