title: Photosonochemical degradation of butyl-paraben: optimization, toxicity and kinetic studies.
abstract: The objective of the present work is to evaluate the potential of a photosonolysis process for the degradation of butyl-paraben (BPB). After 120 min of treatment time, high removal of BPB was achieved by the photosonolysis (US/UV) process (88.0±0.65%) compared to the photochemical (UV) and the conventional ultrasonication (US) processes. Several factors such as calorimetric power, treatment time, pH and initial concentration of BPB were investigated. Using a 2(4) factorial matrix, the treatment time and the calorimetric power are the main parameters influencing the degradation rate of BPB. Subsequently, a central composite design methodology has been investigated to determine the optimal experimental parameters for BPB degradation. The US/UV process applied under optimal operating conditions (at a calorimetric power of 40 W during 120 min and under pH7) is able to oxidize around 99.2±1.4% of BPB and to record 43.3% of mineralization. During the US/UV process, BPB was mainly transformed into 1 hydroxy BPB, dihydroxy BPB, hydroquinone and 4-hydroxybenzoic acid. Microtox biotests (Vibrio fisheri) showed that the treated effluent was not toxic. The pseudo-first order kinetic model (k=0.0367 min(-1)) described very well the oxidation of BPB.
authors.affiliation: Centre des Technologies de l'Eau (CTE), 696, Avenue Sainte-Croix, Montréal, Quebec H4L 3Y2, Canada. Electronic address: rdaghrir@cteau.com.
authors.forename: R
authors.initials: R
authors.lastname: Daghrir
authors.affiliation: Université Paul Sabatier (Laboratoire de Génie Chimique), Université de Toulouse III, 118 Route de Narbonne, C.P. 31062 Toulouse, France. Electronic address: aicha.mpira@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Dimboukou-Mpira
authors.affiliation: Institut National de la Recherche Scientifique (INRS-ETE), Université du Québec, 490 rue de la Couronne, C.P. 7500, Quebec City, Quebec G1K 9A9, Canada. Electronic address: Brahima.Seyhi@ete.inrs.ca.
authors.forename: B
authors.initials: B
authors.lastname: Seyhi
authors.affiliation: Institut national de la Recherche Scientifique (INRS-Eau Terre et Environnement), Université du Quebec, 490 rue de la Couronne, Quebec City, Quebec G1K 9A9, Canada. Electronic address: patrick.drogui@ete.inrs.ca.
authors.forename: P
authors.initials: P
authors.lastname: Drogui
mesh_terms: D008956:Models, Chemical; D010084:Oxidation-Reduction; D010226:Parabens / Q000032:analysis / Q000737:chemistry*; D055668:Photochemical Processes; D013010:Sonication; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D010226:Parabens; D014874:Water Pollutants, Chemical; C038091:butylparaben; C038193:4-hydroxybenzoic acid
keywords: Butyl-paraben; Photosonolysis; Response surface methodology; Wastewater treatment