查看更多>>摘要：Conventional mining of economically and strategically important critical rare earth elements(REEs)(such as neodymium,lanthanum and dysprosium),and chalcogens(such as selenium and tellurium)are associated with a huge economic and environmental cost.Therefore,the need to recover REEs as well as chalcogens from dif-ferent waste streams including wastewaters is becoming urgent.Batch assays on synthetic chalcogen/REE-laden wastewater showed that the presence of REEs significantly improved the tellurite removal rate(＞80％)and enhanced selenate removal by 66％±10％.Three 3.9 L continuous upflow anaerobic granular sludge bed(UASB)reactors were operated at a hydraulic retention time of 24 h and 30 ℃.Selenate reduction was achieved with a removal efficiency of～98％with an influent pH of 4.0 for more than 28 days.The effect of REEs on tellurite removal in the UASB bioreactor could not be clearly established since a soluble tellurium removal efficiency of more than 98％was observed already before the addition of REEs at ele-vated tellurite concentrations.The complete REE removal in both batch assays and UASB reactors at higher pH(7.0±0.5)was attributed to precipitation,whereas chalcogen oxyanions removal was due to microbial reduction.However,at acidic pH,biosorption was responsible for REE's removal,and the Se-enriched sludge exhibited a superior REE's removal efficiency than the non-enriched and Te-enriched sludge.
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