Palmer Sara J, Soisonard Aurore, Frost Ray L
Inorganic Materials Research Program, School of Physical and Chemical Sciences, Queensland University of Technology, Queensland, Australia.
J Colloid Interface Sci. 2009 Jan 15;329(2):404-9. doi: 10.1016/j.jcis.2008.09.065. Epub 2008 Sep 30.
Hydrotalcites with cationic ratios of 2:1, 3:1, and 4:1 were synthesised using the co-precipitation method. The mechanism of inclusion of arsenate, vanadate, and molybdate into these structures is investigated using the combination of X-ray diffraction, Raman spectroscopy, and thermal analysis. Results show that hydrotalcites with cationic ratios of 3:1 are thermally more stable then the 2:1 and 4:1 structures. The increase in thermal stability of the 3:1 hydrotalcite structures is understood to be due to the intercalation of arsenate, vanadate, or molybdate, by an increase in hydrogen bonds associated with the intercalated anion. The 3:1 vanadate hydrotalcite is the most thermally stable hydrotalcite investigated. It is observed that the predominant mechanism for inclusion of the three anionic species is adsorption for 2:1 and 4:1 hydrotalcites, and intercalation for the 3:1 hydrotalcite structures. The intercalation of arsenate, vanadate, and molybdate into the hydrotalcite structure increased the interlayer distance of the hydrotalcite by 0.14, 0.13, and 0.26 A, respectively.
采用共沉淀法合成了阳离子比例为2:1、3:1和4:1的水滑石。结合X射线衍射、拉曼光谱和热分析等手段，研究了砷酸盐、钒酸盐和钼酸盐在这些结构中的嵌入机制。结果表明，阳离子比例为3:1的水滑石在热稳定性上高于阳离子比例为2:1和4:1的结构。3:1水滑石结构热稳定性的提高被认为是由于砷酸盐、钒酸盐或钼酸盐的嵌入，以及与嵌入阴离子相关的氢键增加所致。3:1钒酸盐水滑石是所研究的热稳定性最高的水滑石。研究发现，对于阳离子比例为2:1和4:1的水滑石，三种阴离子物种嵌入的主要机制是吸附，而对于阳离子比例为3:1的水滑石结构，主要机制是插层。砷酸盐、钒酸盐和钼酸盐嵌入水滑石结构后，水滑石的层间距分别增加了0.14 Å、0.13 Å和0.26 Å。
