title: Rapid Photodegradation of Methyl Orange (MO) Assisted with Cu(II) and Tartaric Acid.
abstract: Cu(II) and organic carboxylic acids, existing extensively in soil and aquatic environments, can form complexes that may play an important role in the photodegradation of organic contaminants. In this paper, the catalytic role of Cu(II) in the removal of methyl orange (MO) in the presence of tartaric acid with light was investigated through batch experiments. The results demonstrate that the introduction of Cu(II) could markedly enhance the photodegradation of MO. In addition, high initial concentrations of Cu(II) and tartaric acid benefited the decomposition of MO. The most rapid removal of MO assisted by Cu(II) was achieved at pH 3. The formation of Cu(II)-tartaric acid complexes was assumed to be the key factor, generating hydroxyl radicals (•OH) and other oxidizing free radicals under irradiation through a ligand-to-metal charge-transfer pathway that was responsible for the efficient degradation of MO. Some intermediates in the reaction system were also detected to support this reaction mechanism.
authors.affiliation: College of Sciences, Nanjing Agricultural University, Nanjing 210095, P.R. China.
authors.forename: Jing
authors.initials: J
authors.lastname: Guo
authors.affiliation: College of Sciences, Nanjing Agricultural University, Nanjing 210095, P.R. China.
authors.forename: Xue
authors.initials: X
authors.lastname: Chen
authors.affiliation: College of Sciences, Nanjing Agricultural University, Nanjing 210095, P.R. China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Shi
authors.affiliation: College of Sciences, Nanjing Agricultural University, Nanjing 210095, P.R. China.
authors.forename: Yeqing
authors.initials: Y
authors.lastname: Lan
authors.affiliation: College of Sciences, Nanjing Agricultural University, Nanjing 210095, P.R. China.
authors.forename: Chao
authors.initials: C
authors.lastname: Qin
mesh_terms: D001391:Azo Compounds / Q000528:radiation effects*; D002384:Catalysis; D002413:Cations, Divalent / Q000494:pharmacology*; D002863:Chromogenic Compounds / Q000032:analysis; D003124:Colorimetry; D004396:Coloring Agents / Q000528:radiation effects; D003300:Copper / Q000494:pharmacology*; D005609:Free Radicals; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical; D010084:Oxidation-Reduction; D010782:Photolysis; D011804:Quinolines / Q000032:analysis; D012989:Soil Pollutants / Q000528:radiation effects; D013644:Tartrates / Q000494:pharmacology*
chemical_list: D001391:Azo Compounds; D002413:Cations, Divalent; D002863:Chromogenic Compounds; D004396:Coloring Agents; D005609:Free Radicals; D011804:Quinolines; D012989:Soil Pollutants; D013644:Tartrates; C419881:2,2'-biquinoline; D017665:Hydroxyl Radical; C100258:methyl orange; D003300:Copper; C029768:tartaric acid