title: Biosorption and bioreduction of Cr(VI) by a microalgal isolate, Chlorella miniata.
abstract: The ability and mechanism of a microalgal isolate, Chlorella miniata to remove Cr(VI) were investigated. Kinetic studies indicated that both biosorption and bioreduction were involved in the Cr(VI) removal. The adsorbed Cr(VI) was reduced to Cr(III), and desorption studies indicated that Cr(III) occupied most of the adsorption sites on the biomass. The equilibrium time for Cr(VI) removal was dependent on various factors including initial pH, biomass and Cr(VI) concentrations. Equilibrium study showed that the Cr(VI) removal capacity was negatively related to the initial pH, and the biosorption capacity of total Cr [Cr(III) and Cr(VI)] reached the maximum at initial pH of 3.0. The spectrum of Fourier Transform Infrared Spectrometer analysis (FTIR) further confirmed that amino group on the algal biomass was the main adsorption site for Cr(VI) biosorption in acidic pH while the reduced Cr(III) was mainly sequestered by carboxylate group. The comparison between biosorption-bioreduction and direct bioreduction kinetic models proved that biosorption of Cr(VI) was the first step, followed by Cr(VI) bioreduction and Cr(III) biosorption on the algal biomass.
authors.affiliation: Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Han
authors.forename: Yuk Shan
authors.initials: YS
authors.lastname: Wong
authors.forename: Ming Hung
authors.initials: MH
authors.lastname: Wong
authors.forename: Nora Fung Yee
authors.initials: NF
authors.lastname: Tam
mesh_terms: D000327:Adsorption; D002708:Chlorella / Q000378:metabolism; D002857:Chromium / Q000737:chemistry* / Q000378:metabolism*; D007700:Kinetics; D008962:Models, Theoretical; D010084:Oxidation-Reduction; D017550:Spectroscopy, Fourier Transform Infrared; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000378:metabolism*; D018508:Water Purification / Q000379:methods
chemical_list: D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion