Montmorillonite is a layered clay mineral whose modification by pillaring, i.e., insertion of oxide nanoclusters between the layers, yields porous materials of great potential in sorption and catalysis. In the present study, an unrefined industrial bentonite from Kopernica (Slovakia), containing ca. 70% of montmorillonite, was used for the preparation of Ti-, Zr-, and mixed [Ti,Zr]-pillared clay sorbents. The pillared samples were characterized with X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and N₂ adsorption at −196 °C and tested for the capacity of CO₂ sorption at 0 °C and 1 bar pressure. The experiments revealed that pillared samples sorbed at least four times more CO₂ than the parent bentonite. Of the materials tested, the sample pillared with mixed [Ti,Zr] oxide props showed the best performance, which was attributed to its superior microporosity. The results of CO₂ adsorption demonstrated that the cost-effective use of crude industrial bentonite as the sorbent precursor is a viable synthesis option. In another experiment, all pillared montmorillonites were subjected to 24 h exposure at room temperature to a flow of dry CO₂ and then tested using simultaneous thermal analysis (STA) and the mass spectrometry (MS) analysis of the evolving gases (STA/QMS). It was found that interaction with dry CO₂ reduces the amount of bound carbon dioxide and affects the processes of dehydration, dehydroxylation, and the mode of CO₂ binding in the pillared structure.

This paper summarizes information about recently worked bentonite deposits in Slovakia and presents the results of studies on bentonite from the Central Slovakia Volcanic Field (CSVF). The authors compared the mineralogy of commercial bentonites exploited in the Stara Kremnička (Jelšový potok), Kopernica, and Hliník nad Hronom deposits. X-ray diffraction (XRD), chemical analyses and microscopy showed that the main component is montmorillonite (37-88%), followed by opal C/CT (5-25%), clinoptilolite (up to 15%), feldspars (3-12%), quartz (up to 8%), biotite (2-5%), and kaolinite (up to 2%). The microscopic imaging provided information valuable for the technological assessment of bentonites, particularly the evaluation of mineralogy determined by XRD. The low variability of the mineral composition of commercial bentonites exploited in the western CSVF, together with the significant reserves and localization of deposits close to the Polish-Slovak state border prove that this raw material deserves more attention from Polish industry.