Abstract In order to explore the interactions between Fe-doped kaolinite and coal, the lattice substitution of different valence Fe in kaolinite crystal was analyzed by Mossbauer spectrometer and density functional theory (DFT) calculations. The results show that there are three lattice substitution forms of Fe with different valence states in kaolinite, are mainly six-coordinate Fe2+, four-coordinate Fe3+ and six-coordinated Fe3+, and the difficult and easy level of lattice substitution from easy to difficult is six-coordinate Fe2+ > four-coordinate Fe3+ > six-coordinated Fe3+. According to the results of Mossbauer spectrum analysis and DFT calculation, the best calculation model of Fe-doped kaolinite was determined, and the interactions between Fe-doped kaolinite and coal were investigated in this study through DFT calculations. The results show that the interaction mechanism between Fe-doped kaolinite and coal is the result of hydrogen-bond interaction and the strong electrostatic attraction between benzene rings and Fe-doped kaolinite surfaces, and the interactions between Fe-doped kaolinite and coal are stronger than that between perfect kaolinite and coal. The lattice substitution of Fe mainly enhances the reactivity of kaolinite (0 0 1) surface, and the equilibrium cation Na+ has a certain influence on the reactivity of kaolinite (0 0 1) and ( 00 1 ¯ ) surface. The results can provide a theoretical basis for further study of the true adsorption state of kaolinite surface in coal slurry water.

中文翻译：

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基于DFT计算的Fe掺杂高岭石与煤相互作用的系统探索

摘要 为探究掺铁高岭石与煤的相互作用，利用穆斯堡尔谱仪和密度泛函理论（DFT）计算分析了高岭石晶体中不同价态Fe的晶格置换。结果表明,高岭石中不同价态的Fe存在三种晶格置换形式,主要是六配位Fe2+、四配位Fe3+和六配位Fe3+,从易到难的晶格置换难易程度分别为六配位 Fe2+ > 四配位 Fe3+ > 六配位 Fe3+。根据穆斯堡尔谱分析和DFT计算结果，确定了掺Fe高岭石的最佳计算模型，本研究通过DFT计算研究了掺Fe高岭石与煤的相互作用。结果表明，掺铁高岭石与煤的相互作用机理是氢键相互作用和苯环与掺铁高岭石表面之间强静电引力的结果，掺铁高岭石与煤的相互作用强于介于完美的高岭石和煤炭之间。Fe的晶格置换主要增强了高岭石(0 0 1)面的反应性，平衡阳离子Na+对高岭石(0 0 1)和( 00 1 )面的反应性有一定的影响。研究结果可为进一步研究高岭石表面在煤浆水中的真实吸附状态提供理论依据。