title: Effect of operational parameters on degradation of Malachite Green by ultrasonic irradiation.
abstract: The aim of the present study was to apply ultrasonic technique to remove Malachite Oxalate Green (MG) from aqueous solution. An ultrasonic bath with frequency of 35 kHz was used to investigate the effect of different operational parameters such as MG concentration, power density, temperature, mechanical agitation and addition of EtOH, 2-PrOH and iso-BuOH. Decolorization of MG follows a first order kinetics and hydroxyl radicals have an important role in degradation of MG. The apparent reaction rate constant (k(ap)) was influenced by variation of operational parameters. The activation energy was 30.95 kJ/mol in temperature range of 21-34 degrees C, suggesting a diffusion-controlled reaction. Alcohols act as hydroxyl radicals scavengers having undesirable contribution. UV-vis spectral change of MG showed hypsochromic shift occurred with increasing sonication time, proposing N-demethylation process of MG.
authors.affiliation: Department of Applied Chemistry, Islamic Azad University, Tabriz Branch, P.O. Box 1655, Tabriz, IR, Iran. behnajady@iaut.ac.ir
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Behnajady
authors.forename: Nasser
authors.initials: N
authors.lastname: Modirshahla
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shokri
authors.forename: Behrouz
authors.initials: B
authors.lastname: Vahid
mesh_terms: D000440:Butanols / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry / Q000528:radiation effects; D000431:Ethanol; D016166:Free Radical Scavengers / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D020005:Propanols / Q000737:chemistry; D012394:Rosaniline Dyes / Q000737:chemistry* / Q000528:radiation effects*; D012997:Solvents; D013696:Temperature; D014465:Ultrasonics; D014732:Vibration
chemical_list: D000440:Butanols; D004396:Coloring Agents; D016166:Free Radical Scavengers; D020005:Propanols; D012394:Rosaniline Dyes; D012997:Solvents; C005095:malachite green; D017665:Hydroxyl Radical; D000431:Ethanol