CuMgAl类水滑石的制备和表征

Preparation and characterization of CuMgAl-hydrotalcite-like-compounds

用盐-碱制备法合成了CuMgAl三元类水滑石化合物.探讨了原料配比、合成方式、水热处理温度和时间对合成过程的影响,筛选出合成HTLs的适宜条件,并对HTLcs结构的热稳定性进行初步研究.结果表明,制备HTLcs主要取决于pH值,同时由于Cu2+的姜-太勒效应,合成结构单一的CuMgAl类水滑石要求原料配比中n(Cu):n(Mg)不得超过1.0,CuMgAl-HTLcs热稳定性较差,300℃焙烧2h结构破坏,600℃开始烧结,在300～500℃之间,随焙烧温度提高所得复合氧化物比表面积增大,最高可达200m2/g.

CuMgAl-HTLcs（hydrotalcite-like-compounds） were synthesized mainly by the salt-base method with materials of filtrate and NaOH. The effects of pH value, different ratio of mixed solution, temperature and time of hydrothermal treatment, synthetic ways on relative crystallization were studied. The best conditions of preparing CuMgAl-HTLcs were obtained, The effects of calcite temperature on the structure of HTLcs was preliminary studied. The result showed the preparation of HTLcs mainly depended on pH value, ratio of mixed solution. Due to the Jahn-Teller theorem of Cu^2＋ , the ratio of n （Cu） ： n （Mg） in the HTLcs containing Cu^2＋ should so much the better be less than 1.0.The structure of CuMgAl-HTLcs will be destroyed after 2 h at 300℃ , and begin to agglomerate at 600℃. The results show that the specific surface area of oxides derived from CuMgAl- HTLcs increases with the increase of calcinations temperature within 300-500℃,and can be 200 m^2/g at 500℃ for the highest.