title: Biosorption of Ag(I) from aqueous solutions by Klebsiella sp. 3S1.
abstract: This study investigated the potential ability of Klebsiella sp. 3S1 to remove silver cations from aqueous solutions. The selected strain is a ubiquitous bacterium selected from among several microorganisms that had been isolated from wastewaters. To optimise the operating conditions in the biosorption process, a Rotatable Central Composite Experimental Design was developed establishing pH, temperature and biomass concentration as independent variables. Interaction mechanisms involved were analysed through kinetic and equilibrium studies. The experimental results suit pseudo-second order kinetics with two biosorption stages, being the first almost instantly. The Langmuir equilibrium model predicted a maximum capacity of biosorption (q) of 114.1mg Ag/g biomass. The study of the mechanisms involved in the biosorption was completed by employing advanced techniques which revealed that both bacterium-surface interactions and intracellular bioaccumulation participate in silver removal from aqueous solutions. The ability of Klebsiella sp. 3S1 to form silver chloride nanoparticles with interesting potential applications was also discussed.
authors.affiliation: Department of Chemical, Environmental and Materials Engineering, University of Jaén, 23071 Jaén, Spain.
authors.forename: Antonio Jesús
authors.initials: AJ
authors.lastname: Muñoz
authors.affiliation: Department of Chemical, Environmental and Materials Engineering, University of Jaén, 23071 Jaén, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Espínola
authors.affiliation: Department of Chemical, Environmental and Materials Engineering, University of Jaén, 23071 Jaén, Spain. Electronic address: eruiz@ujaen.es.
authors.forename: Encarnación
authors.initials: E
authors.lastname: Ruiz
mesh_terms: D000327:Adsorption; D007700:Kinetics; D007709:Klebsiella / Q000502:physiology*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D012834:Silver / Q000302:isolation & purification*; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D014874:Water Pollutants, Chemical; D012834:Silver
keywords: AgCl-NPs; FTIR; Isotherm adsorption; Kinetic study; SEM; TEM