title: Ag2O and Fe2O3modified oxides on the photocatalytic treatment of pulp and paper wastewater.
abstract: The effects of doping of ZnO and Nb2O5solids with Fe2O3(1.4 wt%) and Ag2O (1.4 wt%) on its surface and catalytic properties were investigated, as well as its photocatalytic performance on the degradation of a pulp and paper wastewater (PPW). The catalysts were characterized by XRD, SEM, photoacoustic spectroscopy (PAS), NH3-TPD and textural analysis. The results obtained revealed that Fe2O3doping of Nb2O5conducted at 500 °C resulted in an increase of about 116% for SBETwhile Ag2O treatment exerted a decrease of 33% for SBETof the doped adsorbents. Doping ZnO with Fe2O3or Ag2O led to an increase of 80% for SBET. Iron and silver doping also led to a decrease in band gap energy of at least 6%. The addition of 1.4 wt% Ag2O on ZnO followed by calcination at 500 °C resulted in an increase of 11% in the value of the reaction rate constant (kap) for COD reduction under UV radiation. The treatment of Nb2O5with 1.4 wt% Ag2O increased by a factor of 2.04 the value of kapfor the reaction taking place under VIS radiation. The catalysts partially reduced the organic load and the real colour of the wastewater, allowing the achievement of the specifications for release into rivers, so photocatalysis could be an alternative for pulp and paper wastewater final polishing.
authors.affiliation: Universidade Estadual de Maringá, Av. Colombo, 5790, Maringá, PR, Brazil.
authors.forename: R G
authors.initials: RG
authors.lastname: Marques
authors.affiliation: Universidade Tecnológica Federal do Paraná, Rua Marcílio Dias, 635, Apucarana, PR, Brazil. Electronic address: ana_eq@hotmail.com.
authors.forename: A M
authors.initials: AM
authors.lastname: Ferrari-Lima
authors.affiliation: Universidade Estadual do Oeste do Paraná, Rua da Faculdade, 645, Toledo, PR, Brazil.
authors.forename: V
authors.initials: V
authors.lastname: Slusarski-Santana
authors.affiliation: Universidade Estadual de Maringá, Av. Colombo, 5790, Maringá, PR, Brazil.
authors.forename: N R C
authors.initials: NRC
authors.lastname: Fernandes-Machado
mesh_terms: D002384:Catalysis; D005290:Ferric Compounds / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry; D010209:Paper; D062065:Wastewater
chemical_list: D005290:Ferric Compounds; D010087:Oxides; D062065:Wastewater
keywords: Ag(2)O/ZnO; Fe(2)O(3)/Nb(2)O(5); Paper wastewater; Photocatalysis