title: Studies on biosorption equilibrium and kinetics of Cd2+ by Streptomyces sp. K33 and HL-12.
abstract: The sorption of Cd(2+) by Streptomyces sp. K33 and HL-12 was investigated. The removal efficiency increased with pH, but no obvious differences with different temperatures. Fourier transform infrared (FT-IR) was used to characterize the interaction between Cd(2+) and K33 and HL-12. Results revealed that the presence of amino, carboxyl, hydroxyl and carbonyl groups were responsible for the biosorption of Cd(2+). Strain HL-12 had more changes in the functional groups than K33. Biosorption equilibrium was established earlier by strain K33 than that by HL-12, and K33 had higher adsorption ratio. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms were used to describe the adsorption experiment, Langmuir model fitted the experiment data best. Strain K33 showed greater sorption capacities with 38.49 mg Cd(2+)/g dry cells. Pseudo-first-order and second-order kinetic models were used to describe the kinetic data, and second-order kinetic model fitted better. About 70% recovery of Cd(2+) could be obtained at pH <or= 3 from metal-loaded biomass of strains HL-12 and K33.
authors.affiliation: College of Life Science, Zhejiang University, Hangzhou, PR China. hpy_002@tom.com
authors.forename: Hai-ping
authors.initials: HP
authors.lastname: Yuan
authors.forename: Jun-hui
authors.initials: JH
authors.lastname: Zhang
authors.forename: Zhen-mei
authors.initials: ZM
authors.lastname: Lu
authors.forename: Hang
authors.initials: H
authors.lastname: Min
authors.forename: Chu
authors.initials: C
authors.lastname: Wu
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000302:isolation & purification*; D015386:Hazardous Substances / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008956:Models, Chemical; D017550:Spectroscopy, Fourier Transform Infrared; D013302:Streptomyces; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D015386:Hazardous Substances; D014874:Water Pollutants, Chemical; D002104:Cadmium