Abstract FeIII-containing aluminosilicate zeolites are present in cement-relevant and natural environments. Although FeIII is known to occur in framework tetrahedral sites where it substitutes isomorphically AlIIIO4 or in extra-framework octahedral sites as free Fe(H2O)63+, the structural incorporation process of FeIII into different sites is little known. We aim to discern feasible pathways of FeIII incorporation using hydrothermal synthesis methods and synchrotron-based spectroscopic analyses. Results showed that introducing either Fe3+ or Fe2O3·xH2O initially during zeolite nucleation did not lead to FeIII incorporation into the zeolites but only Fe2O3·xH2O prevailed in both cases. However, Fe(NO3)3, FeCl3, and Fe2O3·xH2O affected the kind of zeolite formed. A feasible pathway to incorporate tetrahedral FeIII in the zeolite framework was to introduce firstly FeIII in the cage of faujasite-Y followed by a phase transformation to chabazite. This study facilitates understanding of FeIII uptake in zeolites and of FeIII functional sites that can contribute to immobilization of contaminants.

中文翻译：

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水泥相关环境中 FeIII 结构掺入沸石骨架的光谱研究

摘要 含 FeIII 的铝硅酸盐沸石存在于与水泥相关的自然环境中。虽然已知 FeIII 出现在骨架四面体位点，在那里它替代同构的 AlIIIO4 或在框架外八面体位点作为游离的 Fe(H2O)63+，但 FeIII 到不同位点的结构掺入过程鲜为人知。我们的目标是使用水热合成方法和基于同步加速器的光谱分析来辨别 FeIII 掺入的可行途径。结果表明，在沸石成核过程中最初引入 Fe3+ 或 Fe2O3·xH2O 不会导致 FeIII 掺入沸石，但在这两种情况下只有 Fe2O3·xH2O 占优势。但是，Fe(NO3)3、FeCl3 和 Fe2O3·xH2O 会影响形成的沸石种类。将四面体 FeIII 掺入沸石骨架的可行途径是首先将 FeIII 引入八面沸石-Y 的笼子中，然后相转变为菱沸石。这项研究有助于了解沸石中 FeIII 的吸收和有助于固定污染物的 FeIII 功能位点。