title: Optimization of the electro-Fenton and solar photoelectro-Fenton treatments of sulfanilic acid solutions using a pre-pilot flow plant by response surface methodology.
abstract: A central composite rotatable design and response surface methodology were used to optimize the experimental variables of the electro-Fenton (EF) and solar photoelectro-Fenton (SPEF) degradations of 2.5L of sulfanilic acid solutions in 0.05M Na(2)SO(4). Electrolyses were performed with a pre-pilot flow plant containing a Pt/air diffusion reactor generating H(2)O(2). In SPEF, it was coupled with a solar photoreactor under an UV irradiation intensity of ca. 31Wm(-2). Optimum variables of 100mAcm(-2), 0.5mM Fe(2+) and pH 4.0 were determined after 240min of EF and 120min of SPEF. Under these conditions, EF gave 47% of mineralization, whereas SPEF was much more powerful yielding 76% mineralization with 275kWh kg(-1) total organic carbon (TOC) energy consumption and 52% current efficiency. Sulfanilic acid decayed at similar rate in both treatments following a pseudo-first-order kinetics. The final solution treated by EF contained a stable mixture of tartaric, acetic, oxalic and oxamic acids, which form Fe(III) complexes that are not attacked by hydroxyl radicals formed from H(2)O(2) and added Fe(2+). The quick photolysis of these complexes by UV light of sunlight explains the higher oxidation power of SPEF. NH(4)(+) was the main inorganic nitrogen ion released in both processes.
authors.affiliation: Laboratori d'Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.
authors.forename: Abdellatif
authors.initials: A
authors.lastname: El-Ghenymy
authors.forename: Sergi
authors.initials: S
authors.lastname: Garcia-Segura
authors.forename: Rosa María
authors.initials: RM
authors.lastname: Rodríguez
authors.forename: Enric
authors.initials: E
authors.lastname: Brillas
authors.forename: Mohamed Soussi
authors.initials: MS
authors.lastname: El Begrani
authors.forename: Ben Ali
authors.initials: BA
authors.lastname: Abdelouahid
mesh_terms: D055664:Electrochemical Techniques; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D055668:Photochemical Processes; D010865:Pilot Projects; D012996:Solutions; D013425:Sulfanilic Acids / Q000737:chemistry*
chemical_list: C045076:Fenton's reagent; D012996:Solutions; D013425:Sulfanilic Acids; D006861:Hydrogen Peroxide; D007501:Iron