RT Journal Article
T1 Variability of the surface properties of sepiolite
A1 Súarez Barrios, Mercedes
A1 García Romero, Emilia
AB A comparative study of a wide collection of sepiolites (22 samples from different locations, including samplescoming from the greatest deposits of sepiolite in the world) was made with the aim of understanding the realvariability of the surface properties in sepiolite. The samples have been studied by XRD, Electron Microscopy(TEM and SEM) and the adsorption–desorption of N2. The influence of possible impurities, crystallinity andcrystalline defects, and the textural variations, is taken into account to explain the high differences foundin the specific surface area of sepiolites. The studied samples display a high variability in crystallinity, fibrelength and texture. The BET surface varies between 77 and 399 m2 g−1, demonstrating the significant variationin the surface properties in natural sepiolites. Both the external and the microporous area vary betweenvery wide extreme values, from 52 m2 g−1 to 246 m2 g−1 for the microporous area and 6 m2 g−1 to178 m2 g−1 for the external area. The exceptionally low values of these properties found in some samplescannot be related to the presence of impurities, but rather to their structural and textural features. Twotypes of microporosity that can be described are structural microporosity and interfibre microporosity. TheSSA and the porosity of each sepiolite is the result of the sum of the intracrystalline or structural microporosityand the textural porosity (interfibre microporosity and mesoporosity). As a consequence, there is a hierarchicaldistribution of pore sizes, which is different for each sepiolite. The lowest values of microporosity arerelated to the presence of very open pores and the sepiolites with higher SSA are those having a smallerlength and a more closed porosity.
PB Elsevier
SN 0169-1317
YR 2012
FD 2012
LK https://hdl.handle.net/20.500.14352/43843
UL https://hdl.handle.net/20.500.14352/43843
LA eng
DS Docta Complutense
RD 30 abr 2024