title: Reaction pathways and kinetics of butylated hydroxyanisole with UV, ozonation, and UV/O(3) processes.
abstract: The chemical degradation of the endocrine disrupting chemical, butylated hydroxyanisole (BHA), was investigated by different treatment processes including ultraviolet (UV) irradiation, ozonation (O(3)), and UV/O(3). O demethylation, dimerization, and oxidation have been found to be the main degradation mechanisms. A systematic decay pathway was proposed based on ten identified intermediates in the studied processes, including a unique pathway leading to the formation of precipitates in the ozonation process. An unconventional minimum-type variation of BHA decay rate constants from acidic to caustic range has been found for both ozonation and UV/O(3) processes. The precipitates formed during ozonation can be removed during the process to optimize the treatment, while the UV/O(3) process can offer a relatively fast and clean process to degrade BHA and its associated intermediates.
authors.affiliation: Department of Civil and Structural Engineering, Research Centre for Environmental Technology and Management, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
authors.forename: T K
authors.initials: TK
authors.lastname: Lau
authors.forename: W
authors.initials: W
authors.lastname: Chu
authors.forename: N
authors.initials: N
authors.lastname: Graham
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D002083:Butylated Hydroxyanisole / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010126:Ozone / Q000378:metabolism*; D010782:Photolysis; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D002083:Butylated Hydroxyanisole; D010126:Ozone