title: Removal of anionic azo dye from aqueous solution via an adsorption-photosensitized regeneration process on a TiO2 surface.
abstract: Textile dye effluents are typically characterized by strong color and recalcitrance, even at very low concentration. The process of enrichment of anionic azo dye on the surface of TiO(2) fibers followed by photosensitization degradation under ambient air conditions was extensively investigated. Adsorption isotherms and zeta potentials were used to describe the "dye/TiO(2) surface" interface, taking into account the effects of pH on the nature and population of the surface groups on the TiO(2) fibers. The extent of the photocatalytic degradation of dye on TiO(2) surface was determined by FTIR. N(2) adsorption isotherms and optical spectra were employed to investigate the effect of photosensitization. The adsorption of dyes on the TiO(2) surface occurs via electrostatic attraction through the formation of single- or multidentate-coordinated surface complexes. Almost complete photobleaching of the absorption band at 534 nm is achieved in ~4 h. Dye-sensitized TiO(2) fiber could absorb part of the visible light spectrum (λ < 600 nm). Interfacial electron transfer can potentially alter the degradation efficiency. The regenerated TiO(2) fiber could be reused for subsequent decolorization without a decline in adsorption efficiency compared with freshly prepared TiO(2) samples, which may be attributed to preservation of the hierarchical pore structure and restoration of the original surface properties. In summary, we propose an efficient "adsorption-photoregeneration-reuse" process applying TiO(2) fibers for the degradation of dyes in water.
authors.affiliation: School of Environmental Science and Engineering, Shandong Key Laboratory of Water Pollution Control and Resource Reuse, Shandong University, Jinan 250100, Peoples Republic of China. baonan@sdu.edu.cn
authors.forename: Nan
authors.initials: N
authors.lastname: Bao
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Yu
authors.forename: Jun-Jian
authors.initials: JJ
authors.lastname: Niu
authors.forename: Guo-Lin
authors.initials: GL
authors.lastname: Wu
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Xu
mesh_terms: D000327:Adsorption; D000838:Anions; D001391:Azo Compounds / Q000737:chemistry* / Q000302:isolation & purification; D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry* / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D009281:Naphthalenes / Q000737:chemistry / Q000302:isolation & purification; D009282:Naphthalenesulfonates / Q000737:chemistry / Q000302:isolation & purification; D038761:Photobleaching; D012996:Solutions; D013499:Surface Properties; D013783:Textile Industry; D014025:Titanium / Q000737:chemistry*; D014227:Triazines / Q000737:chemistry / Q000302:isolation & purification; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000838:Anions; D001391:Azo Compounds; D004396:Coloring Agents; D009281:Naphthalenes; D009282:Naphthalenesulfonates; D012996:Solutions; D014025:Titanium; D014227:Triazines; D062065:Wastewater; D014874:Water Pollutants, Chemical; C520101:Reactive brilliant red X-3B; C463839:reactive red 3B; C009495:titanium dioxide