Department Institut de Science des Matériaux de Mulhouse IS2M, Université de Haute Alsace (UHA), CNRS, UMR 7361, F-68100 Mulhouse, France.
Université de Strasbourg, 67081 Strasbourg, France.
Molecules. 2020 Feb 20;25(4):944. doi: 10.3390/molecules25040944.
The influence of the compensating cation (Na, Li, Mg) nature on the water adsorption properties of LTA and FAU-type zeolites was investigated. Cation exchanges were performed at 80 °C for 2 h using 1 M aqueous solutions of lithium chloride (LiCl) or magnesium chloride (MgCl). XRF and ICP-OES analyses indicate that the cation exchange yields reach values between 59 to 89% depending on the number of exchange cycles and the nature of the zeolite and cation, while both zeolites structures are preserved during the process, as shown by XRD and solid state NMR analyses. Nitrogen adsorption-desorption experiments indicate a higher available microporous volume when sodium cations are replaced by smaller monovalent lithium cations or by divalent magnesium cations because twice less cations are needed compared to monovalent cations. Up to 15% of gain in the available microporous volume is obtained for FAU-type zeolites exchanged with magnesium cation. This improvement facilitates the adsorption of water with an increase in the water uptake up to 30% for the LTA and FAU type zeolites exchanged with magnesium. These exchanged zeolites are promising for uses in water decontamination because a smaller amount is needed to trap the same amount of water compared to their sodium counterparts.
研究了补偿阳离子（Na、Li、Mg）性质对 LTA 和 FAU 型沸石水吸附性能的影响。在 80°C 下，使用 1 M 氯化锂（LiCl）或氯化镁（MgCl）水溶液进行阳离子交换 2 小时。XRF 和 ICP-OES 分析表明，阳离子交换产率取决于交换周期的次数和沸石和阳离子的性质，在 59%至 89%之间，而沸石结构在整个过程中都得到了保留，这一点通过 XRD 和固态 NMR 分析得到了证实。氮气吸附-解吸实验表明，当钠离子被更小的单价锂离子或二价镁离子取代时，微孔体积的可用空间更大，因为与单价阳离子相比，所需的阳离子数量减少了一半。对于用镁阳离子交换的 FAU 型沸石，可用微孔体积的增加高达 15%。这种改进促进了水的吸附，对于用镁交换的 LTA 和 FAU 型沸石，水的吸附量增加了 30%。与它们的钠离子对应物相比，这些交换后的沸石在水净化方面具有很大的应用前景，因为与它们相比，需要更少的沸石来捕获相同量的水。
