title: Photocatalytic degradation of humic acids using substrate-supported Fe³⁺-doped TiO₂ nanotubes under UV/O₃ for water purification.
abstract: In this paper, Fe(3+)-doped TiO2 nanotubes (Fe-TNTs) were successfully synthesized using hydrothermal method. Four different types of substrates, more specifically, ceramsite, zeolite, activated alumina, and activated carbon (AC), have been investigated in the study. The substrate-supported Fe-TNTs were used to effectively decompose humic acids (HAs) in water under O3/UV conditions. The experiment results show that the highest photocatalytic activity was obtained in the presence of AC-supported 1.0 atomic percent (at.%) Fe-TNTs calcined at 500 °C, as HAs was removed by 97.4%, with a pseudo-first-order rate constant of 0.126/min. The removal efficiencies of HAs reduced when the catalysts was repeatedly used, since the amount of adsorption sites of the supporting substrates decreased. However, even after the catalyst was repeatedly used for five times, the removal efficiency of HAs in the presence of AC-supported catalyst, which was 78.5%, was still sufficient in water treatment. The enhanced photocatalytic activity of AC-supported Fe-TNTs was related to a synergistic effect of AC adsorption and Fe-TNT photocatalytic ozonation.
authors.affiliation: Department of Environmental Engineering, School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
authors.forename: Rongfang
authors.initials: R
authors.lastname: Yuan
authors.affiliation: Department of Environmental Engineering, School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China. zhoubeihai@sina.com.
authors.forename: Beihai
authors.initials: B
authors.lastname: Zhou
authors.affiliation: Department of Environmental Engineering, School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
authors.forename: Xuemin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Environmental Engineering, School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
authors.forename: Huanhuan
authors.initials: H
authors.lastname: Guan
mesh_terms: D000327:Adsorption; D002384:Catalysis; D002606:Charcoal / Q000737:chemistry; D006812:Humic Substances; D007501:Iron / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry; D010126:Ozone / Q000737:chemistry*; D055668:Photochemical Processes; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods*
chemical_list: D006812:Humic Substances; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D002606:Charcoal; D010126:Ozone; D014025:Titanium; D007501:Iron
keywords: Activated alumina (Al2O3); Activated carbon (AC); Fe3+-doped TiO2 nanotubes (Fe-TNTs); Humic acids; Zeolite