Alazreg Asma, Tadić Vladisav, Egelja Adela, Savić Andrija, Šaponjić Aleksandra, Vuksanović Marija M, Heinemann Radmila Jančić
Faculty of Technology and Metallurgy, University of Belgrade, 11000 Belgrade, Serbia.
Department of Chemical Dynamics and Permanent Education, "VINČA" Institute of Nuclear Sciences-National Institute of the Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia.
Materials (Basel). 2025 Jan 3;18(1):162. doi: 10.3390/ma18010162.
A layered double hydroxide (LDH) containing Mg and Al was synthesized from a nitrate solution using a coprecipitation method. The resulting material exhibited a homogeneous structure, which, upon calcination at 450 °C, was converted into a layered double oxide (LDO). When rehydrated in a fluoride-containing aqueous solution, the original hydroxide structure was successfully regenerated, demonstrating the LDH's memory effect. During this transformation, fluoride anions from the solution were incorporated into the interlayer galleries to maintain electroneutrality, as confirmed by energy-dispersive X-ray spectroscopy (EDS) analysis. Separately, the process was tested in the presence of ethanol, which significantly enhanced the incorporation of fluoride ions into the interlayer spaces. The material's potential for controlled fluoride release was evaluated by monitoring its release into demineralized water. For comparison, a simple ion-exchange process was carried out using the as-synthesized MgAl LDH. The memory effect mechanism displayed a notably higher fluoride incorporation capacity compared to the ion-exchange process. Among all the specimens, the sample reconstructed in the presence of ethanol exhibited the highest fluoride ion content. Fluoride release studies revealed a two-phase pattern: an initial rapid release within the first three hours, followed by a substantially slower release over time.
采用共沉淀法从硝酸盐溶液中合成了一种含镁和铝的层状双氢氧化物（LDH）。所得材料呈现出均匀的结构，在450℃煅烧后转化为层状双氧化物（LDO）。当在含氟水溶液中再水化时，原始的氢氧化物结构成功再生，证明了LDH的记忆效应。在这个转变过程中，溶液中的氟阴离子被纳入层间通道以保持电中性，这通过能量色散X射线光谱（EDS）分析得到证实。另外，该过程在乙醇存在下进行了测试，乙醇显著增强了氟离子向层间空间的掺入。通过监测其向去离子水中的释放来评估该材料控制氟释放的潜力。作为比较，使用合成的MgAl LDH进行了简单的离子交换过程。记忆效应机制显示出比离子交换过程更高的氟掺入能力。在所有样品中，在乙醇存在下重构的样品表现出最高的氟离子含量。氟释放研究揭示了一种两相模式：在前三个小时内初始快速释放，随后随着时间的推移释放速度大幅减慢。
