Abstract Changes of crystal morphology and size of calcium sulfate hemihydrate (HH) by Al3+ ions, synthesized by hydrothermal method, were carried out to understand the interaction mechanism between the metal ion and crystal surface. The preferential adsorption of Al3+ on the top crystal surface was confirmed by XPS and ICP-OES, and the interaction mechanism was evaluated by molecular dynamics (MD). It was observed that the Al3+ ions significantly inhibited the HH growth along c-axial. The shape of HH crystal with the increasing of Al3+ ions concentration (0 to 10 mM), changed from whiskers to short rod-like. The position of Al3+ ions into the structure by molecular dynamics simulation showed preferential adsorption on active sites of (0 0 2) face, which inhibited the growth rate and leaded to the formation of short rod-like HH. This provided a guide for the research of calcium sulfate whiskers preparation from industrial gypsum.

中文翻译：

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Al 3+ 对半水硫酸钙晶体形态和尺寸的影响：实验和分子动力学模拟研究

摘要 通过水热法合成的Al3+离子对半水合硫酸钙(HH)晶体形貌和尺寸的改变，研究了金属离子与晶体表面的相互作用机理。XPS和ICP-OES证实了Al3+在顶部晶体表面的优先吸附，并通过分子动力学（MD）评估了相互作用机制。观察到 Al3+ 离子显着抑制了 HH 沿 c 轴的生长。HH晶体的形状随着Al3+离子浓度的增加(0～10mM)，由晶须状变为短棒状。分子动力学模拟表明Al3+离子在结构中的位置显示优先吸附在(0 0 2)面的活性位点上，这抑制了生长速率并导致形成短棒状HH。