膨润土改性制备多孔结构钛锂离子筛前驱体

Synthesis of porous bentonite modified titanium-lithium ion sieve precursor

以Ti(SO)为钛源,CHCOOLi·2H_(2)O为锂源,NH_(3)·H_(2)O为沉淀剂,H_(2)O_(2)为络合剂,采用沉淀胶溶法制备了钛酸锂前驱体溶胶,添加膨润土,经搅拌、陈化、干燥、煅烧后得到膨润土改性Li_(2)TiO_(2)_(3)粉体。研究了络合剂H_(2)O_(2)与Ti的摩尔比(R)、煅烧温度、膨润土与溶胶的固液比对Li_(2)TiO_(2)_(3)的表面形貌及晶体结构的影响。采用扫描电镜、X射线衍射、热重-差示扫描量热、红外光谱对样品进行表征。结果表明,当R=6时,未改性的Li_(2)TiO_(2)_(3)在750℃煅烧下,晶体结构最完整。按1.67 g/L的固液比添加膨润土对样品进行改性后,煅烧温度为750℃时各晶面结晶最完整,得到表面呈均匀多孔结构的Li_(2)TiO_(2)_(3)。

The lithium titanate precursor sol was prepared by inorganic precipitation-peptization method with titanium sulfate as titanium source, lithium acetate as lithium source, followed by adding bentonite as modifier. Bentonite modified Li_(2)TiO_(2)_(3)powder was obtained after stirring, aging, drying and calcination. The effects of molar ratio (R) of complexing agent H_(2)O_(2)to Ti, calcination temperature, solidliquid ratio of bentonite to sol on the surface morphology and crystal structure of precursor Li_(2)TiO_(2)_(3)were studied. The samples were characterized by scanning electron microscopy, X-ray diffraction, thermogravimetry-differential scanning calorimetry and infrared spectroscopy. The results show that the crystal structure of unmodified Li_(2)TiO_(2)_(3) is the most complete when calcined at 750 ℃ with R=6. After the sample was modified by bentonite with a solid-liquid ratio of 1.67 g/L, the crystallinity of each crystal surface was the most complete when the calcination temperature was 750 ℃, and Li_(2)TiO_(2)_(3)with uniform porous structure on the surface was obtained.