title: Adsorption of the diazo dye Direct Red 23 onto a zinc oxide surface: a spectroscopic study.
abstract: The adsorption of the diazo dye Direct Red 23 onto a zinc oxide surface at 30 degrees C in the dark was investigated. The color reduction was monitored by spectrophotometry at 503 nm. The FTIR and Raman spectra of the Direct Red 23 adsorption as a function of ZnO concentration were registered. From the PM3 semi-empirical calculations of the atomic charge density and dipole moment of the Direct Red 23 molecule, it was demonstrated that the azo dye molecule may be adsorbed onto the ZnO surface through molecule geometry modifications, enhancing the interfacial area causing a variation in the bonding frequencies.
authors: Department of Chemistry, CCE, Londrina State University, Londrina, PR, Brazil.
authors: Adriana Campano
authors: AC
authors: Lucilha
authors: Carlos Eduardo
authors: CE
authors: Bonancêa
authors: Wagner José
authors: WJ
authors: Barreto
authors: Keiko
authors: K
authors: Takashima
mesh_terms: D000327:Adsorption; D000813:Anilides / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry; D015394:Molecular Structure; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D000813:Anilides; D001391:Azo Compounds; D004396:Coloring Agents; D014874:Water Pollutants, Chemical; C506598:1-(2-methoxy-5-nitrophenylazo)-2-hydroxy-3-(3-nitrophenylcarbamoyl)naphthalene; D015034:Zinc Oxide