Synthesis and characterization of micro-mesoporous solids: pillared clays

In this work, the synthesis and characterization of micro-mesoporous materials obtained from clays, with Fe, Co and Rh are presented. These materials can be used in Catalysis or Adsorption when the necessary active phases are those metals. The porous materials were Pillared Clays — PILCs — synthesized from a natural Spanish laminar clay with two kinds of Aluminum oligocations. One of these oligocations was obtained from a suspension of a commercial product, Locron (aluminum chlorhydrate), and the other was synthesized in the laboratory from Aluminum chloride and sodium hydroxide solutions. Two Al-PILCs were prepared from these oligocations: the first one (from Locron) by a quick method; the second one by a conventional method. Both Al-PILCs show differences in their acidity and porous distribution related to the presence of Al-pillars with different structure. They also show a great increase in their basal distance and their specific area, which is associated to the formation of microporous. Both pillared clays were impregnated with Co, Fe or Rh solutions and then characterized by different techniques — AAS, XRD, N2-sorption and acidity studies by TGA — obtaining data about their porosity and location of the metals in oxidize state. After the impregnation, the specific area decreases but keeps some of their porous structure if compared with the PILCs. To conclude, materials with stable porous characteristics are obtained from natural clays in order to be used in catalytic and adsorption processes.