纳米级水氯铁镁石的制备及颗粒团聚控制

水氯铁镁石是具有Mg/Fe结构层的一类特殊阴离子粘土,具有典型的阴离子粘土层状结构、较大的比表面积和热分解特性,是吸附和催化领域内性能优异的新型粘土材料,而纳米水氯铁镁石颗粒的团聚是阻碍其性能开发的关键问题,本文从材料合成、超声分散和悬浮液干燥3个方面阐述了纳米水氯铁镁石制备过程中颗粒团聚的机理和控制措施,并利用XRD、透射电子显微镜、扫描电镜、粒径分布和比表面积等检测手段对合成产物进行表征.研究表明,通过快速沉淀-水热法合成的水氯铁镁石悬浮液颗粒呈薄片状,具有完整的正六边形晶型,粒径大多在166~675 nm,选用有机溶剂洗涤,并缩短晶化时间,采用最低限度的超声分散,冷冻干燥有助于制备颗粒尺寸小、表面细腻、排列整齐的水氯铁镁石纳米材料,最终达到理想的分散效果.

Synthesis and agglomeration control of nanocrystalline iowaite

Iowaite is a kind of anion clay contained Mg/Fe in the layer and has typical layer structure, large surface area and thermal decomposition,which performs well in adsorption and catalysis as a novel clay material. However, the particle agglomeration of nanocrystalline iowaite becomes the main factor that impedes the exploitation of its capability,and the comparative research about its synthesis and agglomeration control is not reported. In this paper,the agglomerate mechanism and control measures in synthesizing nanocrystalline iowaite are explained in three aspects:material preparation,ultrasonic dispersion and slurry drying. The compound was characterized by XRD,TEM,SEM, particle size distribution and specific surface area. It turned out that, via the rapid precipitation-hydrothermal method, the synthetic nano-iowaite suspension acted as orthohexagonal platelets and the particles mostly distributed within 166~675 nm.The organic solvent washing,short crystallined time,minimal ultrasonic dispersion and freeze drying were beneficial to the synthesis of nanosized iowaite with the smaller size,delicate surface and regular arrangement,ultimately achieving the desirable dispersed effect.