Microbial extracellular polymeric substances (EPS) have gained increasing attention for various water treatment applications. In this study, EPS produced from nitrogen-limited glycerol/ethanol-rich wastewater were used to recover Cu2+ and Pb2+ from aqueous solutions. Continuous flow-through tests were conducted on a column packed with silica gel coated with polyethyleneimine, to which EPS were irreversibly attached as shown by optical reflectometry. These immobilised EPS excellently adsorbed Cu2+ and Pb2+, with 99.9% of influent metal adsorbed before the breakthrough points. Metal desorption was achieved with 0.1M HCl, with an average recovery of 86% for Cu2+ and 90% recovery for Pb2+. For the first time, we successfully showed the possibility to regenerate and reuse the immobilised EPS for five adsorption-desorption cycles (using Cu2+ as an example) with no reduction in the adsorbed amount at the breakthrough point (qbp). Based on the mass balance of the associated metal ions participating in the adsorption process, ion exchange was identified as the major mechanism responsible for Cu2+ and Pb2+ adsorption by EPS. The results demonstrate the potential of wastewater-produced EPS as an attractive and perhaps, cost-effective biosorbent for heavy metal removal (to trace effluent concentrations) and recovery (86-99%).

中文翻译：

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固定在床柱上用于重金属回收的微生物细胞外聚合物的再生和再利用。

微生物细胞外聚合物（EPS）在各种水处理应用中越来越受到关注。在这项研究中，从含氮受限的甘油/乙醇富集废水中产生的EPS用于从水溶液中回收Cu2 +和Pb2 +。在填充有聚乙烯亚胺的硅胶填充的色谱柱上进行连续的流通测试，EPS不可逆地附着在其上，如光学反射法所示。这些固定的EPS极好地吸附了Cu2 +和Pb2 +，在突破点之前有99.9％的流入金属被吸附。用0.1M HCl可使金属脱附，Cu2 +的平均回收率为86％，Pb2 +的平均回收率为90％。首次，我们成功地展示了在五个吸附-解吸循环中（以Cu2 +为例）再生并重新使用固定化EPS的可能性，并且在突破点（qbp）处的吸附量没有减少。根据参与吸附过程的相关金属离子的质量平衡，离子交换被认为是EPS吸附Cu2 +和Pb2 +的主要机理。结果表明，废水产生的EPS具有潜在的吸引力，也许是具有成本效益的生物吸附剂，可用于去除重金属（以痕量废水浓度）和回收（86-99％）。离子交换被认为是EPS吸附Cu2 +和Pb2 +的主要机理。结果表明，废水产生的EPS具有潜在的吸引力，也许是具有成本效益的生物吸附剂，可用于去除重金属（以痕量废水浓度）和回收（86-99％）。离子交换被认为是EPS吸附Cu2 +和Pb2 +的主要机理。结果表明，废水产生的EPS作为一种有吸引力的，也许是具有成本效益的生物吸附剂，具有去除重金属（以痕量废水浓度）和回收（86-99％）的潜力。