title: Anodic oxidation of o-nitrophenol on BDD electrode: variable effects and mechanisms of degradation.
abstract: The electrochemical oxidation of pesticide, o-nitrophenol (ONP) as one kind of pesticide that is potentially dangerous and biorefractory, was studied by galvanostatic electrolysis using boron-doped diamond (BDD) as anode. The influence of several operating parameters, such as applied current density, supporting electrolyte, and initial pH value, was investigated. The best degradation occurred in the presence of Na2SO4 (0.05 M) as conductive electrolyte. After 8h, nearly complete degradation of o-nitrophenol was achieved (92%) using BDD electrodes at pH 3 and at current density equals 60 mA cm(-2). The decay kinetics of o-nitrophenol follows a pseudo-first-order reaction. Aromatic intermediates such as catechol, resorcinol, 1,2,4-trihydroxybenzene, hydroquinone and benzoquinone and carboxylic acids such as maleic glycolic, malonic, glyoxilic and oxalic, have been identified and followed during the ONP treatment by chromatographic techniques. From these anodic oxidation by-products, a plausible reaction sequence for ONP mineralization on BDD anodes is proposed.
authors.affiliation: Materials, Environment and Energy Laboratory (06/UR/12-01), Science Faculty of Gafsa, 2112, University of Gafsa, Tunisia. chimie_tunisie@yahoo.fr
authors.forename: Nejmeddine
authors.initials: N
authors.lastname: Rabaaoui
authors.forename: Mohamed El Khames
authors.initials: Mel K
authors.lastname: Saad
authors.forename: Younes
authors.initials: Y
authors.lastname: Moussaoui
authors.forename: Mohamed Salah
authors.initials: MS
authors.lastname: Allagui
authors.forename: Ahmed
authors.initials: A
authors.lastname: Bedoui
authors.forename: Elimame
authors.initials: E
authors.lastname: Elaloui
mesh_terms: D016227:Benzoquinones / Q000737:chemistry; D001895:Boron / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry; D002396:Catechols / Q000737:chemistry; D018130:Diamond; D004566:Electrodes; D004572:Electrolysis; D006863:Hydrogen-Ion Concentration; D006873:Hydroquinones / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D009596:Nitrophenols / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D010575:Pesticides / Q000302:isolation & purification; D012118:Resorcinols / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods
chemical_list: D016227:Benzoquinones; D002264:Carboxylic Acids; D002396:Catechols; D006873:Hydroquinones; D009596:Nitrophenols; D010575:Pesticides; D012118:Resorcinols; D014874:Water Pollutants, Chemical; C013038:hydroxyhydroquinone; C004532:quinone; D018130:Diamond; C034221:catechol; D001895:Boron; D010100:Oxygen; C031927:hydroquinone; C031389:resorcinol