The specific roles of extracellular polymeric substances (EPS) and how factors influenced EPS’s roles during U(VI) immobilization are still unclear. In this study, high content of U with the main form of nanoparticles was detected in EPS, accounting for 10–42% of total U(VI) removal. EPS might be utilized as energy source or even as electron donors when external carbon source was unavailable. The influencing degree of each experimental parameter to uranium (U) removal process was elucidated. The influential priority to U(IV)/U(VI) ratios in sludge was as follows: acetate, U(VI), and nitrate. The influential priority to total EPS contents was as follows: U(VI), nitrate and acetate. The complex interaction mechanism between U(VI) and EPS in the U immobilization process was proposed, which might involve three ways including biosorption, bioreduction and bioprecipitation. These results indicate important and various roles of EPS in U(VI) immobilization.

中文翻译：

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细胞外聚合物在厌氧污泥固定化铀中的作用。

尚不清楚细胞外聚合物（EPS）的具体作用以及在U（VI）固定过程中因素如何影响EPS的作用。在这项研究中，EPS中检测到高含量的以纳米颗粒主要形式存在的U，占U（VI）去除总量的10-42％。当没有外部碳源时，EPS可能被用作能源甚至电子供体。阐明了每个实验参数对铀（U）去除过程的影响程度。对污泥中U（IV）/ U（VI）比的影响优先级如下：乙酸盐，U（VI）和硝酸盐。对总EPS含量的影响优先级如下：U（VI），硝酸盐和乙酸盐。提出了U（VI）与EPS在U固定化过程中的复杂相互作用机理，可能涉及生物吸附，吸附，吸附，吸附，吸附等三种途径。生物还原和生物沉淀。这些结果表明EPS在U（VI）固定中的重要作用和各种作用。