title: Mineralization of C.I. Reactive Yellow 84 in aqueous solution by sonolytic ozonation.
abstract: The operational parameters and mechanism of mineralization of C.I. Reactive Yellow 84 (RY84), one of the azo dyes, in aqueous solution were investigated using sonolytic ozonation (US/O(3) oxidation). Of the pseudo-first-order degradation rate constants of TOC reduction, 9.0 x 10(-4), 7.3 x 10(-3) and 1.8 x 10(-2)min(-1) were observed with US, O3, and a combination of US and O3, respectively. These results illustrate that ozonation combined with sonolysis for removal of TOC is more efficient than ozonation alone or ultrasonic irradiation alone without considering the operating costs. With the initial pH value at 10.0, the ozone dose at 4.5 g h(-1), the energy density of ultrasound at 176 W l(-1), and the initial concentration of RY84 at 100 mg l(-1), the extent of mineralization measured as TOC loss was maximized. The variation of the concentrations of related ions (oxalate, formate, acetate, NO3(-), NO2(-), NH4(+), Cl(-), and SO4(2-)) during the reaction process was monitored. Other organic intermediates detected by GC/MS were N-methyleneaniline, phthalic acid, 4-hydroxyphthalic acid, isocyanatobenzene, aniline, 4-iminocyclohexa-2,5-dien-1-one, butene diacid and urea. Based on these findings, a tentative degradation pathway was proposed.
authors.affiliation: College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, People's Republic of China.
authors.forename: Zhiqiao
authors.initials: Z
authors.lastname: He
authors.forename: Shuang
authors.initials: S
authors.lastname: Song
authors.forename: Min
authors.initials: M
authors.lastname: Xia
authors.forename: Jianping
authors.initials: J
authors.lastname: Qiu
authors.forename: Haiping
authors.initials: H
authors.lastname: Ying
authors.forename: Bosheng
authors.initials: B
authors.lastname: Lü
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Jiang
authors.forename: Jianmeng
authors.initials: J
authors.lastname: Chen
mesh_terms: D004396:Coloring Agents / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D008903:Minerals / Q000737:chemistry*; D010126:Ozone / Q000737:chemistry*; D012996:Solutions; D014867:Water / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D008903:Minerals; D012996:Solutions; D014867:Water; D010126:Ozone