Zinc Sorption by a Bacterial Biofilm

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• 作者：Brandy Toner ; Alain Manceau ; Matthew A. Marcus ; Dylan B. Millet ; and Garrison Sposito
• 刊名：Environmental Science & Technology
• 出版年：2005
• 出版时间：November 1, 2005
• 年：2005
• 卷：39
• 期：21
• 页码：8288 - 8294
• 全文大小：199K
• 年卷期：v.39,no.21(November 1, 2005)
• ISSN：1520-5851

文摘

Microbial biofilms are present in soils, sediments, andnatural waters. They contain bioorganic metal-complexingfunctional groups and are thought to play an importantrole in metal cycling in natural and contaminatedenvironments. In this study, the metal-complexing functionalgroups present within a suspension of bacterial cellaggregates embedded in extracellular polymeric substances(EPS) were identified in Zn adsorption experimentsconducted at pH 6.9 with the freshwater and soil bacteriumPseudomonas putida. The adsorption data were fit withthe van Bemmelen-Freundlich model. The molecularspeciation of Zn within the biofilm was examined with ZnK-edge extended X-ray absorption fine structure (EXAFS)spectroscopy. The Zn EXAFS data were analyzed by shell-by-shell fitting and linear least-squares fitting withreference spectra. Zinc sorption to the biofilm was attributedto predominantly Zn-phosphoryl (85 ± 10 mol %)complexes, with a smaller contribution to sorption fromcarboxyl-type complexes (23 ± 10 mol %). The results ofthis study spectroscopically confirm the importance ofphosphoryl functional groups in Zn sorption by a bacterialbiofilm at neutral pH.