重要事项如下，非放射性锶（Sr）是由铀和钍等重元素的放射性衰变产生的。非放射性锶与钙具有物理化学相似性，在骨骼形成过程中可以替代钙，从而可能在人体中引发骨癌。因此，关于与锶相关的潜在危害，有必要予以消除。本研究旨在调查赤铁矿吸附的锶被钙溶液所去除的机制。锶在pH 8和10处被赤铁矿吸附，并用钙溶液进行洗涤。对洗涤前后的样品进行了X射线吸收近边结构（XANES）、扩展X射线吸收精细结构（EXAFS）、扫描电子显微镜、X射线衍射（XRD）和X射线光电子能谱（钙洗涤后）的测试。通过XANES和EXAFS的分析和拟合，确认了锶在pH 10下形成内层配合物。XRD光谱显示锶在pH 8和10下分别形成SrCO3和SrFe2O4。在用钙溶液洗涤后，锶被直接替代形成CaCO3和CaFe2O4。X射线光电子能谱的结果对赤铁矿和锶的比例进行了系统分析，确认了锶与钙的替代作用。这种替代可以归因于钙和锶之间的物理化学相似性。该研究证实了Sr与Ca的替代，突出了Sr和Ca之间的物理化学相似性促进了替代反应。版权所有 © 2023. 由Elsevier Ltd.出版。

Nonradioactive strontium (Sr) are produced as a result of radioactive decay of heavier elements such as uranium and thorium. Nonradioactive Sr shares physicochemical similarities with Ca and can replace it during bone formation, which may cause bone cancer in humans. Hence, concerning the potential hazards associated with strontium, it is imperative to eliminate it. The present study aimed to investigate the removal mechanisms of hematite-adsorbed strontium by calcium solution. Strontium was adsorbed to hematite at pH 8 and 10 and washed with calcium solution. X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS), scanning electron microscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (after Ca washing) were performed on the samples before and after washing. Analyses and fitting by XANES and EXAFS confirmed the formation of an inner-sphere complex of strontium at pH 10. The XRD spectra showed that SrCO3 and SrFe2O4 formed at pH 8 and 10, respectively. After washing with the calcium solution, strontium was directly substituted to form CaCO3 and CaFe2O4. The X-ray photoelectron spectroscopy results provided a systematic analysis of the proportions of hematite and strontium, confirming the substitution of strontium with calcium. This substitution could be attributed to the physicochemical similarities between calcium and strontium. This study confirms the substitution of Sr with Ca, highlighting the physicochemical similarity of the Sr and Ca that facilitates substitution reactions.Copyright © 2023. Published by Elsevier Ltd.