Anion-exchange and thermal change of layered zinc hydroxides formed in the presence of Al(III)
Anion-exchange and thermal change of layered zinc hydroxides formed in the presence of Al(III)
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DOI：
10.1016/j.colsurfa.2006.07.018
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发表时间：
2007-02-01
影响因子：
5.2
通讯作者：
Nakayama, Takenori
中科院分区：
文献类型：
--
作者：
Ishikawa, Tatsuo;Matsumoto, Kumi;Nakayama, Takenori
在Al/Zn=0.1和0.6的条件下，用氯化锌溶液溶解AlCl3制备了ZHC(硅藻土，Zn-5(OH)Scl(2)中心点H2O)和层状双氢氧化物(LDH，Zn-Al-Cl)氢氧化锌颗粒。用X射线衍射仪、透射电子显微镜、傅立叶变换红外光谱、锌、铝、氯分析和N-2、H2O、CCl4气体吸附等方法研究了ZHC和LDH的阴离子交换和热变化。形成的ZHC和LDH颗粒分别为六方薄板和不规则形状的薄板。与ZHC相比，LDH更容易与CO32-和SO42-进行离子交换。与SO42-的离子交换破坏了LDH的层状结构，而与CO32-的离子交换破坏了ZHC的层状结构，而与两种阴离子交换后的层状结构保持不变。在75-400℃不同温度下放气的ZHC和LDH粒子的透射电子显微镜观察表明，在100-150℃放气时ZHC发生剥离，而LDH不发生剥离。当放气温度低于100℃时，ZHC对H2O表现出较高的吸附选择性，而在125℃以上发生剥离时，吸附选择性完全消失。另一方面，LDH的吸附选择性低于ZHC，但在400℃放气后仍能保持选择性。ZHC在真空中的分层促进作用表明，ZHC表现出比LDH更弱的层间引力。(C)2006爱思唯尔B.V.保留所有权利。
Zinc hydroxide chloride particles of ZHC (simonkolleite, Zn-5(OH)sCl(2)center dot H2O) and layered double hydroxides (LDH, Zn-Al-Cl) were prepared by hydrolysis of ZnCl2 solutions dissolving AlCl3 at Al/Zn=0.1 and 0.6 in atomic ratio, respectively. The anion-exchange and thermal change of ZHC and LDH were investigated by XRD, TEM, FTIR, analysis of Zn, Al, and Cl and gas adsorption of N-2, H2O, and CCl4. The formed ZHC and LDH particles were hexagonal thin plates and irregularly shaped thin plates, respectively. LDH was more easily ion-exchanged with CO32- and SO42- compared to ZHC. The layered structure of LDH was damaged by the ion-exchange with SO42- but not CO32-, whereas that of ZHC was kept after the ion-exchange with both the anions. The TEM observation of the ZHC and LDH particles outgassed at different temperatures of 75-400 degrees C revealed that exfoliation takes place on outgassing ZHC at 100-150 degrees C but not occurs in LDH. ZHC showed a high H2O adsorption selectivity when outgassed below 100 degrees C, however the adsorption selectivity completely disappeared above 125 C where the exfoliation took place. On the other hand, LDH exhibited less adsorption selectivity than ZHC though the selectivity was held after outgassed at 400 degrees C. The facilitated delamination of ZHC indicates that ZHC exhibits weaker interlalyer attractive force than LDH in vacuo. (c) 2006 Elsevier B.V. All rights reserved.