title: Electrochemical and sonoelectrochemical processes applied to amaranth dye degradation.
abstract: Amaranth dye is an organic compound largely used in the food and beverage industries with potential toxicity effects on humans. It can be found as a pollutant species in aquatic environments and has been classified as an endocrine disruptor. This study describes amaranth degradation upon ultrasonication associated with an electrochemical system that uses a boron-doped diamond anode BDD, defined as a sonoelectrochemical process. Ninety-minute electrolyses were performed using current densities in the 10-50 mA cm(-2) range, and the concentration decay, pH, energy and current efficiencies, as well as the discoloration rate were evaluated. The amaranth concentration decayed as a function of electrolysis time and the reactions obeyed pseudo first-order kinetics, with an apparent constant rate between 10(-1) and 10(-3)min(-1). The electrochemical and sonoelectrochemical processes at 35 mA cm(-2) yielded TOC removal values between 92.1% and 95.1% respectively, after 90 min. Current efficiency values obtained for both processes were 18.2% and 23.6%. Exhaustive 5h electrolysis was performed and the degradation products were identified by HPLC-MS. A mechanism for the degradation of amaranth was proposed based on an analysis of the aromatic and aliphatic intermediates.
authors: São Carlos Institute of Chemistry, University of São Paulo, Avenida Trabalhador São Carlense 400, CEP 13566-590 São Carlos, SP, Brazil.
authors: Juliana R
authors: JR
authors: Steter
authors: São Carlos Institute of Chemistry, University of São Paulo, Avenida Trabalhador São Carlense 400, CEP 13566-590 São Carlos, SP, Brazil.
authors: Willyam R P
authors: WR
authors: Barros
authors: São Carlos Institute of Chemistry, University of São Paulo, Avenida Trabalhador São Carlense 400, CEP 13566-590 São Carlos, SP, Brazil.
authors: Marcos R V
authors: MR
authors: Lanza
authors: São Carlos Institute of Chemistry, University of São Paulo, Avenida Trabalhador São Carlense 400, CEP 13566-590 São Carlos, SP, Brazil. Electronic address: artur@iqsc.usp.br.
authors: Artur J
authors: AJ
authors: Motheo
mesh_terms: D000548:Amaranth Dye / Q000737:chemistry*; D001895:Boron / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D018130:Diamond / Q000737:chemistry; D004566:Electrodes; D004572:Electrolysis; D007700:Kinetics; D013058:Mass Spectrometry; D013010:Sonication; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D014874:Water Pollutants, Chemical; D018130:Diamond; D000548:Amaranth Dye; D001895:Boron
keywords: Amaranth dye; BDD anode; Degradation pathways; Sonoelectrochemistry; Ultrasound