title: Electrochemical degradation of aromatic amines on BDD electrodes.
abstract: The electrochemical oxidation of four aromatic amines, with different substituent groups, 3-amino-4-hydroxy-5-nitrobenzenesulfonic acid (A1), 5-amino-2-methoxybenzenesulfonic acid (A2), 2,4-dihydroxyaniline hydrochloride (A3) and benzene-1,4-diamine (A4), was performed using as anode a boron-doped diamond electrode, commercially available at Adamant Technologies. Tests were run at room temperature with model solutions of the different amines, with concentrations of 200 ppm, using as electrolyte 0.035 M Na(2)SO(4) aqueous solutions, in a batch cell with recirculation, at different current densities (200 and 300 A m(-2)). The following analyses were performed with the samples collected during the assays: UV-Vis spectrophotometry, chemical oxygen demand (COD), total organic carbon (TOC), total Kjeldahl nitrogen, ammonia nitrogen, nitrates and HPLC. Results have shown a good electrodegradation of all the amines tested, with COD removals, after 6 h assays, higher than 90% and TOC removals between 60 and 80%. Combustion efficiency (η(C)), which measures the tendency to convert organic carbon to CO(2), was also determined for all the amines, being η(CA1)<η(CA2)<η(CA3)<η(CA4)=0.99.
authors.affiliation: UMTP and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal. mjap@ubi.pt
authors.forename: M J
authors.initials: MJ
authors.lastname: Pacheco
authors.forename: V
authors.initials: V
authors.lastname: Santos
authors.forename: L
authors.initials: L
authors.lastname: Ciríaco
authors.forename: A
authors.initials: A
authors.lastname: Lopes
mesh_terms: D000588:Amines / Q000032:analysis*; D057919:Biological Oxygen Demand Analysis; D001896:Boron Compounds / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D018130:Diamond; D004563:Electrochemistry; D004566:Electrodes; D006841:Hydrocarbons, Aromatic / Q000032:analysis*; D017745:Incineration; D010100:Oxygen / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000588:Amines; D001896:Boron Compounds; D006841:Hydrocarbons, Aromatic; D002244:Carbon; D018130:Diamond; D010100:Oxygen