title: Mechanism and dynamic study of reactive red X-3B dye degradation by ultrasonic-assisted ozone oxidation process.
abstract: The effectiveness of ozone combined with ultrasound techniques in degrading reactive red X-3B is evaluated. A comparison among ozone (O3), ultrasonic (US), ozone/ultrasonic (O3/US) for degradation of reactive red X-3B has been performed. Results show that O3/US system was the most effective and the optimally synergetic factor reaches to 1.42 in O3/US system. The cavitation of ultrasound plays an important role during the degradation process. It is found that 99.2% of dye is degraded within 6min of reaction at the initial concentration of 100mg·L-1, pH of 6.52, ozone flux of 40L·h-1and ultrasonic intensity of 200W·L-1. Ozonation reactions in conjunction with sonolysis indicate that the decomposition followed pseudo-first-order reaction kinetics but the degradation efficiencies are affected by operating conditions, particularly initial pH and ultrasonic intensity. A kinetic model is established based on the reaction corresponding to operational parameters. In addition, the main reaction intermediates, such as p-benzoquinone, catechol, hydroquinone, phthalic anhydride and phthalic acid, are separated and identified using GC/MS and a possible degradation pathway is proposed during the O3/US process.
authors.affiliation: School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China. Electronic address: shenyj@ntu.edu.cn.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Shen
authors.affiliation: School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China.
authors.forename: Qihui
authors.initials: Q
authors.lastname: Xu
authors.affiliation: School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China.
authors.forename: Rongrong
authors.initials: R
authors.lastname: Wei
authors.affiliation: School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China.
authors.forename: Jialing
authors.initials: J
authors.lastname: Ma
authors.affiliation: School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
keywords: Degradation pathway and mechanisms; Kinetics; Ozonation; Reactive red X-3B; Sonolysis