Preparation of alumina-pillared layered tetratitanates with different interlayer spacings

The synthesis of pillared clays have led to the development of new materialswith suitable pore size and sufficient stability to be used as shape-selective catalystsand molecular sieves. There are numerous layered inorganic oxides which havethe potential to undergo ion-exchange reactions analogous to those observed withclays, but the nonswelling nature of most ionic layered oxides generally prevents

Synthesis and characterization of chromia-pillared layered tetratitanate

The first chromia-pillared layered tetratitanate was prepared by the reaction of layered tetramethylammonium tetratitanate with chromium (III) acetate [Cr(OAc)3] aqueous solution and subsequent calcination of the resultant solid product in air at 400°C. The obtained chromia-pillared layered tetratitanate has an interlayer distance of 1.06 nm and a high thermal stability up to 600°C. It was also found that calcination in N2 led to the chromia-pillared layered tetratitanate with relatively higher Brunauer-Emmett-Teller (BET) specific surface area (93.9 m2·g?1) and smaller average pore diameter (4.44 nm) than that in air (82.0 m2·g?1, 7.61 nm). Both Br?nsted and Lewis acid sites (mainly Lewis type) are present on the chromia-Pillared layered tetratitanate (500°C, N2, 8 h) and strong enough to still remain a small proportion of pyridine upon outgassing at 250°C. Moreover, ammonia temperature-programmed desorption (NH3-TPD) result showed that there were three NH3 desorption peaks at 160, 200 and 315°C, respectively. The corresponding acid amount is 41.3, 73.9 and 290.7 μmol·g?1. The total acid amount is 405.9 μmol·g?1.

用溶剂热处理法制备TiO_2纤维及其光催化降解甲基橙的活性

在不同温度下 ,用甘油常压热处理层状水合钛酸 (H2 Ti4O9·nH2 O)制备了TiO2 纤维 ,并用XRD进行了表征 .结果表明 ,经 6 0 ,15 0和 2 5 0℃甘油热处理后 ,样品的主晶相均为H2 Ti8O17,得到有较大比表面积和有微孔结构的TiO2 纤维 ;当处理温度为 15 0℃时 ,制得的TiO2 纤维比表面积由原来的 30m2 /g增大到 12 7m2 /g ,其中小于 1nm的微孔比表面积为 79m2 /g .以甲基橙为代表物 ,考察了TiO2 纤维的光催化活性 .与在空气中热处理相比 ,甘油常压热处理提高了TiO2 纤维的光催化氧化活性 ,其降解甲基橙的能力优于P 2 5 .

具有超大通道结构的介孔氧化硅柱层状钛酸的合成和催化应用初探

A mesoporous(d=2.3mm)silica-pillared layered tetratita nate with a super gallery(d 001 =1.84mm)was prepared by first preswelling layered tetratitanate with n-dodecyl amine,then reacting with 20wt%NH 2 (CH 2 ) 3 Si (OC 2 H 5 ) 3 aqueous solution,and finally calcinating the resultant solid product i n air at 550℃.All the reaction was carried out hydrothermally in an aut oclave at 130℃.The obtained materia l has a relatively high BET surface area of204m 2 ·g -1 and a thermal stability beyond 600℃.The catalytic application of the material was also investigated by using the dehydration of isopropanol and the reform of n-hexane as two probing reactions.

胺基化四钛酸材料吸附直接湖蓝5B性能

微波酸化K2Ti4O9，正十二胺微波胺基化改性H2Ti4O9，获得正十二胺柱撑的层状钛酸材料．研究了其作为吸附剂，pH、初始染料质量浓度、吸附剂用量等因素对直接湖蓝5B偶氮染料吸附的影响，确定最佳条件．研究结果表明：微波法改性钛酸钾材料，具有良好的吸附性能；pH为2～4，脱色时间为40min，吸附剂用量为1g／L，温度为40℃时饱和吸附量最大，达到1333mg／g，吸附等温式能较好地符合Langmuir和Freundlich方程模型参数．

微波胺基化四钛酸材料的合成研究

将m(TiO2):m(K2CO3)=3:1采用KDC(kneading-drying-calcination)法合成K2Ti4O9,经微波酸化得H2Ti4O9,再经正十二胺微波胺基化改性,获得正十二胺柱撑的层状化合物,利用XRD、IR和元素分析仪测定了材料的表征特性,并研究了微波辐照时间和功率对有机物进入层间量及层间距的影响。结果表明:采用微波胺基化改性钛酸钾材料,易于在层间引入正十二胺,层间距达2.803～3.923nm;微波辐射3h,约有48.5%H+离子与十二胺键合;层间距随微波辐照时间增长和功率增大而增大,且微波辐照时间的影响要大于微波辐照功率。

有机胺插层四钛酸对直接湖蓝5B的吸附性能研究

在微波辅助下对四钛酸进行了有机胺插层,获得了正辛胺﹑正十二胺﹑正十六胺插层四钛酸材料,研究了3种层状物质作为吸附剂,pH﹑震荡时间﹑吸附剂用量等因素对直接湖蓝5B偶氮染料吸附的影响,确定了3种材料吸附的最佳条件。研究表明:微波有机胺插层四钛酸材料具有优良的吸附性能,pH=1.0时,正辛胺插层四钛酸用量为0.8 g/L﹑振荡时间40 min,正十二胺插层材料和正十六插层材料用量为0.4 g/L﹑振荡时间分别30 min和50 min时,吸附脱色效果最好。随染料浓度增大,温度升高,插层四钛酸材料会发生板层分离,表现为常规的物理吸附过程。在50℃时,正辛胺﹑正十二胺﹑正十六插层四钛酸对直接湖蓝5B染料的吸附量分别达到636 mg/g﹑3 349 mg/g﹑2 856 mg/g。

正十二胺支撑钛酸材料对染料吸附行为研究

通过静态吸附实验,深入研究了正十二胺支撑钛酸材料对酸性红和茜素红染料的吸附行为。对吸附等温线进行典型吸附模式模拟研究发现:该吸附反应为放热反应,温度越高,吸附性能越好;对酸性红染料表现为典型的Langmu ir吸附模型,对茜素红染料表现为多段吸附模型;308 K下,对酸性红染料的最大吸附量高达590 mg/g,对茜素红染料的最大吸附量为144.5 mg/g,吸附染料性能佳。结合XRD结构表征进一步推断出该吸附过程的机理。