%0 Journal Article
%A Súarez Barrios, Mercedes
%A Santiago Buey, Cristina de
%A García Romero, Emilia
%A Martín Pozas, José M.
%T Textural and structural modifications ofsaponite from Cerro del Aguila by acidtreatment
%D 2001
%@ 0009-8558
%U https://hdl.handle.net/20.500.14352/58537
%X The physicochemical properties of clays can be modified by acid treatment withinorganic acids. This treatment is usually referred to as ‘acid activation’ , because it increases thespecific surface area and the number of active sites of the solids. In the present study, the acidactivation of saponite from Cerro del Aguila (Madrid, Spain) with HCl solutions was measured.Illite, quartz and small amounts of feldspar were found as impurities in the raw saponite.Acid treatments were carried out with different concentrations of HCl solutions. The samplesobtained were characterized by mineralogical and chemical analyses, XRD, FT-IR spectroscopy, N2adsorption-desorption isotherms and TEM. The acid attack, under the conditions employed, produceda progressive destruction of the structure of saponite by partial dissolution of the octahedral Mg(II)cations. Amorphous silica coming from the tetrahedral sheet of saponite was generated. The specificsurface area of the most intensely treated sample (2.5% for 24 h) was doubled with respect to that ofnatural saponite. This increase in the surface area is due to the increase in both the external andinternal surface areas.
%~