摘要
采用共沉淀法制备了Mg2Al1，Zn2Al1和Mg1Zn1Al1类水滑石（LDHs），利用XRD，FT-IR和TG／DTA等表征手段，对三种LDHs的热分解性质及焙烧物在Na2CO3水溶液中水化恢复层状结构的能力进行对比研究．结果表明：在400～700℃温度范围内，Zn2Al1 LDH和Mg2Al1 LDH的焙烧物中均出现氧化物相（ZnO和MgO）和尖晶石相（ZnAl2O4和MgAl2P4相），而Mg1Zn1Al1 LDH的焙烧物中始终以ZnO相为主，仅在700℃时出现微弱的MgAl2O4相．三种LDHs的焙烧物经Na2CO3溶液处理后恢复层状结构的能力大小为：Mg1Zn1Al1 LDH〉Mg2Al1 LDH〉Zn2Al1 LDH，其与焙烧物的组成有关．原始LDHs的层间含CO3^2-和NO3^-，而恢复后的LDHs层间仅含CO3^2-．随LDHs中Mg含量增加，热失重温度向高温区移动．
Mg1Al1, Zn2Al1 , Mg1Zn1Al1 hydrotalcite-like materials （LDHs） were synthesized by a co-precipitation method. The thermal decomposition behavior of these LDHs and the reconstruction of their decomposition products in Na2CO3 aqueous solution were investigated by employing Power x-ray diffraction, Fourier transform infrared spectroscopy and Thermal analysis. In the temperature range from 400℃ to 700℃, the calcinations of Zn2Al1 LDH and Mg2Al1 LDH resuited in an oxide phase （ZnO or MgO） and a spinel phase （MgAl2O4 or ZnAl2O4）, but for Mg1Zn1Al1 LDH the oxide phase of ZnO is always dominant in the decomposition products. The thermal decomposition products of these LDHs could rehydrate in the Na2CO3 solution and recon structed their layered structures. The order of the reconstruction ability was Mg1Zn1Al1 LDH〉 Mg2Al1 LDH〉Zn2Al1 LDH, which was possibly related to the components in the thermal decomposition products. There were anions CO3^2- and NO3^- in the interlayer of the original LDHs, but only CO3^2- existed in the interlayer of the reconstructed LDHs. In addition, the losing weight temperature increased with the increase of the Mg^2＋ content in LDHs.
出处
《浙江工业大学学报》
CAS
2006年第1期37-42,共6页
Journal of Zhejiang University of Technology
关键词
类水滑石
热分解
水化
层状结构
hydrotalcite like materials
thermal decomposition
hydration
layered structure
