xmlui.ArtifactBrowser.SimpleSearch.filter.source:Scientific papers of the University of Pardubice. Series A, Faculty of Chemical Technology. 21/2015
ISSN:1211-5541
Abstract:
The aim of this work is to compare the structure and basicity of Mg-Al mixed
oxides with the same Mg/Al molar ratio (Mg/Al 2) synthesised by means of
different procedures. We have focused on the preparation of Mg-Al mixed oxides
by the thermal pre-treatment of hydrotalcites synthesized by co-precipitation
method. The individual methods differed from the application of alkaline solution
used to control the reaction pH. We used two solutions, 0.5 M Na2CO3 + 3 M
NaOH and 2 M NaOH, respectively. Moreover, MgO and two Mg-Al mixed oxides
available to large-scale were used to compare the structure and basicity with
those of materials synthesized in laboratory. The structure and basicity of Mg-Al
mixed oxides were analysed by using XRD, N2-adsorption, TGA, and TPD-CO2.
As found, the Mg-Al mixed oxide prepared by the thermal pre-treatment of
hydrotalcite material and synthesised in the concentrated NaOH solution has
exhibited a lower total concentration of basic sites as well as lower relative
amount of medium/strong basic sites, in comparison with the Mg-Al mixed oxides
originating from the hydrotalcites in the carbonate form.