This study demonstrated the removal and recovery of uranium(VI) in a fed-batch stirred tank reactor (STR) using waste digested activated sludge (WDAS). The batch adsorption experiments showed that WDAS can adsorb 200 (±9.0) mg of uranium(VI) per g of WDAS. The maximum adsorption of uranium(VI) was achieved even at an acidic initial pH of 2.7 which increased to a pH of 4.0 in the equilibrium state. Desorption of uranium(VI) from WDAS was successfully demonstrated from the release of more than 95% of uranium(VI) using both acidic (0.5 M HCl) and alkaline (1.0 M Na₂CO₃) eluents. Due to the fast kinetics of uranium(VI) adsorption onto WDAS, the fed-batch STR was successfully operated at a mixing time of 15 min. Twelve consecutive uranium(VI) adsorption steps with an average adsorption efficiency of 91.5% required only two desorption steps to elute more than 95% of uranium(VI) from WDAS. Uranium(VI) was shown to interact predominantly with the phosphoryl and carboxyl groups of the WDAS, as revealed by in situ infrared spectroscopy and time-resolved laser-induced fluorescence spectroscopy studies. This study provides a proof-of-concept of the use of fed-batch STR process based on WDAS for the removal and recovery of uranium(VI).

这项研究表明使用废料消化的活性污泥（WDAS）在补料分批搅拌釜反应器（STR）中去除和回收铀（VI）。分批吸附实验表明，每克WDAS WDAS可以吸附200（±9.0）mg铀（VI）。即使在酸性初始pH值为2.7（在平衡状态下pH值增加到4.0）下，铀（VI）的吸附量也达到最大。通过使用酸性（0.5 M HCl）和碱性（1.0 M Na ₂ CO ₃）释放超过95％的铀（VI），成功地证明了WDAS中铀（VI）的解吸。）洗脱液。由于铀（VI）吸附到WDAS上的动力学很快，因此分批补料STR在15分钟的混合时间成功运行。十二个连续的铀（VI）吸附步骤的平均吸附效率为91.5％，仅需两个解吸步骤即可从WDAS洗脱出95％以上的铀（VI）。原位红外光谱和时间分辨激光诱导荧光光谱研究表明，铀（VI）主要与WDAS的磷酸基和羧基发生相互作用。这项研究提供了使用基于WDAS的补料分批STR工艺去除和回收铀（VI）的概念证明。