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Biosorption Of Heavy Metal Ions On Magnetotactic Bacteria And Mechanism Of Nano-gold Preparation

Posted on:2011-07-10Degree:MasterType:Thesis
Country:ChinaCandidate:J LiFull Text:PDF
GTID:2121330338481178Subject:Chemical Engineering
Abstract/Summary:PDF Full Text Request
Because of the quantum size and the macroscopic quantum tunnel of nano-gold,the nano-gold is applicated in the DNA recognition, the heredity medicine, thenano-catalysis and so on. In this work, the magnetotactic bacteria (MTB) namedMSR-1 is harnessed to capture heavy metal ions in their aquatic solution under thetheory of biosorption, and adsorption 0characterization of single and binary systemswere investigated deeply. In addition, based on the research of biosorption, reductionmechanism of preparing nano-gold with MTB is investigated in this paper.In this paper, the biosorption characteristic of single systems including Cu2+, Ag+and Au3+ by MSR-1 were investigated. The effects of pH value, temperature, theamount of MTB, time, the initial concentration to the biosorption of MTB wereanalyzed. 1Isothermal adsorption and 2absorption dynamics were simulated, and 3modelparameter was obtained. The results of equilibrium and kinetic studies indicated thatthe Langmuir model and the pseudo second order kinetic model could describe thebiosorption of Cu2+, Ag+ and Au3+ with MTB well.The biosorption characteristic of binary systems including Ag+-Cu2+ andAu3+-Cu2+ by MSR-1 were also studied in this article. The results of the biosorptionexperiments of MTB to Ag+-Cu2+ and Au3+-Cu2+ binary systems showed a highselectivity to Ag (I) and Au (III) in binary systems.Moreever, adsorption isotherm ofbinary systems was simulated by Langmuir adsorption model and the correspondingmodel parameters were obtained.Overall, experimental results were agreed withsimulation results well of Ag (I) and Au (III). The expression of Cu (II) was obtainedby fitting.Finally, the reduction mechanism of MSR-1 in the removal of Au (III) wasdiscussed with Transmission electron microscope (TEM), X-ray diffraction (FRD)and X-ray photoelectron spectroscopy (XPS). The results indicated that the process ofreduction was AuCl3·HCl→AuCl→Au0. The lower pH value and the initialconcentration of Au (III) of the solution were, the smaller the nano-gold was.
Keywords/Search Tags:magnetotactic bacterium, heavy metal ions, biosorption, nano-gold
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