Sorption of Strontium by Bacteria, Fe(III) Oxide, and Bacteria-Fe(III) Oxide Composites

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• 作者：Troy D. Small ; Lesley A. Warren ; Eric E. Roden ; and F. Grant Ferris
• 刊名：Environmental Science & Technology
• 出版年：1999
• 出版时间：December 15, 1999
• 年：1999
• 卷：33
• 期：24
• 页码：4465 - 4470
• 全文大小：158K
• 年卷期：v.33,no.24(December 15, 1999)
• ISSN：1520-5851

文摘

This study provides the first quantitative comparison ofthe sorptive capacities of a bacteria-Fe oxide compositeto its individual components. These results have enormoussignificance for understanding the fate and transportof inorganic contaminants in natural aqueous environmentswhere heterogeneous bacteria-oxide composite solidsare commonly found. We quantify Sr²⁺ sorption to the bacteriaShewanella alga, Shewanella putrefaciens, amorphoushydrous ferric oxide (HFO), and S. alga coated with HFOover a range of total Sr²⁺ concentrations (0.005-10 mM) andpH (2.5-11 at 0.5 pH increments), under well controlledlaboratory conditions. Significant Sr²⁺ sorption occurred atsignificantly lower pH values to the bacteria and S. alga-HFO composite (5.5-5.9) compared to HFO (7.6). Geochemical modeling using a generalized Langmuir equation showedthat the bacteria sorb significantly greater quantities ofSr²⁺ (maximum sorptive capacity: BSr_max = 0.079 and 0.075mmol·g^-1 for S. alga and S. putrefaciens, respectively)than the HFO (0.001 mmol·g^-1). The observed BSr_max for theS. alga-HFO composite (0.034 mmol·g^-1) was less thanthe combined sorptive properties of its components (BSr_max= 0.041 mmol·g^-1), likely reflecting HFO masking ofbacterial surface binding sites.