title: Effects of sonochemical parameters and inorganic ions during the sonochemical degradation of crystal violet in water.
abstract: This work deals with the ultrasonic degradation (800 kHz) of crystal violet (CV) under different experimental conditions. The effects of saturating gas (argon, carbon dioxide and air), CV concentration (2.45-1225 μmol L(-1)), pH (3-9) and power (20-80 W) were evaluated. The best performances were obtained at 80 W with argon as a saturating gas. The pH had no significant effect. The influence of several water matrices containing anions (chloride, sulphate and bicarbonate) and cations (Fe(2+)) on the sonolytic degradation of CV was also investigated. Significant differences were not observed with the presence of chloride and sulphate. However, at relatively low pollutant concentration (2.45 μmol L(-1)) bicarbonate showed a particular effect: a high bicarbonate concentration (350 mmol L(-1)) produced a detrimental effect, while a low bicarbonate concentration (3 mmol L(-1)) increased the efficiency of the process. The presence of Fe(2+) (1 mmol L(-1)) also increased the CV (49 μmol L(-1)) degradation by 32% after 180 min. Analyses of intermediates by GC-MS led to the identification of several sonochemical by-products: N,N-dimethylaminobenzene, 4-(N,N-dimethylamino)-4'-(N',N'-dimethylamino)benzophenone, and N,N,N',N'-tetramethyl-4,4'-diaminodiphenylmethane. The presence of these aromatic structures showed that the main ultrasonic CV degradation pathway is linked to the reaction with *OH radicals. At the end of the treatment, these early products were converted into biodegradable organic by-products which could be easily treated in a subsequent biological treatment.
authors.affiliation: Grupo de Diagnóstico y Control de La Contaminación, Facultad de Ingeniería, Universidad de Antioquia, A.A. 1226 Medellín, Colombia.
authors.forename: Fernando
authors.initials: F
authors.lastname: Guzman-Duque
authors.forename: Christian
authors.initials: C
authors.lastname: Pétrier
authors.forename: Cesar
authors.initials: C
authors.lastname: Pulgarin
authors.forename: Gustavo
authors.initials: G
authors.lastname: Peñuela
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Torres-Palma
mesh_terms: D001639:Bicarbonates / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry*; D003460:Crystallization; D005296:Ferrous Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry*; D014465:Ultrasonics; D032413:Viola / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D001639:Bicarbonates; D002712:Chlorides; D005296:Ferrous Compounds; D007477:Ions; D013431:Sulfates; D014867:Water