title: Adsorption of Ag (I) from aqueous solution by waste yeast: kinetic, equilibrium and mechanism studies.
abstract: One type of biosorbents, brewer fermentation industry waste yeast, was developed to adsorb the Ag (I) in aqueous solution. The result of FTIR analysis of waste yeast indicated that the ion exchange, chelating and reduction were the main binding mechanisms between the silver ions and the binding sites on the surface of the biomass. Furthermore, TEM, XRD and XPS results suggested that Ag(0) nanoparticles were deposited on the surface of yeast. The kinetic experiments revealed that sorption equilibrium could reach within 60 min, and the removal efficiency of Ag (I) could be still over 93 % when the initial concentration of Ag (I) was below 100 mg/L. Thermodynamic parameters of the adsorption process (ΔG, ΔH and ΔS) identified that the adsorption was a spontaneous and exothermic process. The waste yeast, playing a significant role in the adsorption of the silver ions, is useful to fast adsorb Ag (I) from low concentration.
authors.affiliation: Key Laboratory of Catalysis and Materials Science of Hubei Province, College of Chemistry and Materials, South-central University for Nationalities, Wuhan, 430-074, Hubei, People's Republic of China.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Zhao
authors.forename: Dongfang
authors.initials: D
authors.lastname: Wang
authors.forename: Hezhen
authors.initials: H
authors.lastname: Xie
authors.forename: Sung Wook
authors.initials: SW
authors.lastname: Won
authors.forename: Longzhe
authors.initials: L
authors.lastname: Cui
authors.forename: Guiping
authors.initials: G
authors.lastname: Wu
mesh_terms: D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D012834:Silver / Q000378:metabolism*; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014867:Water; D015003:Yeasts / Q000378:metabolism*
chemical_list: D012996:Solutions; D014867:Water; D012834:Silver