摘要
采用ＭｎＯ－４和Ｍｎ２＋在强碱性条件下制得层状结构的Ｍｇ＿Ｂｉｒｎｅｓｓｉｔｅ，用ＸＲＤ（Ｘ射线多晶粉末衍射）、ＦＴ－ＩＲ（傅里叶红外光谱）、ＴＧ－ＤＴＧ／ＤＴＡ（热失重－微商热失重／热分析）等方法对它进行了表征。Ｍｇ＿Ｂｉｒｎｅｓｉｔｅ在２００～４００℃时为无定形，在６００℃生成结晶良好的Ｍｎ２Ｏ３相。ＣＣｌ４、ＣＨ３ＯＨ、ｎ＿Ｃ６Ｈ１４的吸附等温线类似于第三种类型的吸附等温线，在接近饱和的情况下都有凝聚现象产生。在６００℃，比表面和吸附数据表明出现层状结构塌陷。吸附吡啶ＦＴ－ＩＲ谱表明在Ｍｇ＿Ｂｉｒｎｅｓｉｔｅ中存在非质子酸（Ｌ酸）和质子酸（Ｂ酸）酸位。
Mg_Birnessite,a layer_structured manganese oxide,was prepared by the redox reaction between Mn^2+and MnO_4 under strong alkaline conditions.Its characterization was carried out by means of X-ray diffraction (XRD),Fourier-transform infrared spectrophotometry (FT-IR),thermal gravity-differential thermal gravity analysis/differential thermal analysis(TG_DTG/DTA).Mg-Birnessite upon heating between 200～400 ℃ is turned to an amorphous phase.At 600 ℃ it is transformed into a well crystalline Mn_2O_3 phase.Adsorption isotherms of CCl_4,CH_3OH and n-C_6H_14 vapors are analogous to the third-type isotherms.In all cases,condensation occurred near saturation points.At 600 ℃,the specific surface area and adsorption data suggest the collapse of the layer structure.The FT_IR spectra of adsorbed pyridine show the presence of both Lewis and Brnsted acid sites in Mg-Birnessite.
出处
《分析测试学报》
CAS
CSCD
1998年第2期20-23,共4页
Journal of Instrumental Analysis
