Pillared montmorillontes from unusual antiperspirant aqueous solutions: Characterization and catalytic tests

Preparation of Al/Fe-Pillared Clays: Effect of the Starting Mineral

“…The adsorption–desorption isotherms of the refined and pillared clays are shown in Figure 4 . The isotherms of the starting refined materials are type IV (a) according to the IUPAC system ( Figure 4 and Figure S2 in Supplementary Material ) [ 42 ], corresponding to mesoporous materials [ 43 ]. The C3-R aluminosilicate presented an adsorption–desorption curve with a higher separation between the branches of adsorption and desorption; it means this material presented high capillary condensation [ 4 ].…”

Preparation of Al/Fe-PILC clay catalysts from concentrated precursors: enhanced hydrolysis of pillaring metals and intercalation

“…This effect was clearly avoided when the hydrolysis ratio was increased as in the case of the intercalating solution Al/Fe-Al 0 2.58 that clearly achieved the Al/Fe-pillaring. On the other hand, the adsorption/desorption isotherms of the C2-N and C2-R starting materials belonged to type II according to the IUPAC classication, 33 typical of mesoporous materials, 20 whose measured surface area is mostly due to external area ( Fig. 3 and S2 †).…”

“…Meanwhile, the isotherms of all Al/Fe-modied materials displayed intermediate behaviour between type I at low relative pressures, and type II at high p/p o according to the BDDT classication, 33 featuring mixed mesoporous and microporous solids. 20 The specic surface area of the materials modied by the NS intercalation method was mainly represented by the generation of micropores with the largest physisorbed volumes on both starting materials. Besides, all solids obtained from the rened clay (C2-R) exhibited higher adsorbed volumes in comparison to those prepared from the natural mineral (C2-N), verifying the strong favourable effect of the previous particle-size rening on the textural properties of the nal solids, including microporous surface and total volume of pores.…”

“…All solids were prepared with the Al/Fe-hydrolysed precursors in proper amount to obtain a nal loading of 20 meq (Al 3+ + Fe 3+ ) per g clay. The intercalating procedures (a) and (b) were adapted from our previous work, 4 whereas the method (c) was adopted from Kooli et al: 20 (a) Addition of the intercalating solution over the ethanolclay-dispersion. The starting clay was previously dispersed in ethanol (25% w/v) and swollen under magnetic stirring at room temperature for 16 h; then, the Al/Fe-hydrolysed solution was slowly dropped under stirring for 2 h over the clay-ethanol dispersion.…”

“…10 Other techniques such as microwave 2,8,17,18 or ultrasound irradiation have been also used for this purpose; 2,5,19 these methods allowed to decrease between 70-90% the synthesis and intercalation time, but they imply the consumption of an extra amount of energy. Other works dealing over the intercalation of Al or Al/Fe solutions 20,21 reported the use of either an antiperspirant intercalating solution or the straightforward addition of raw clays (not previously swollen) over up to 40% clay's suspensions attaining Alpillared materials with a signicant increase in basal spacing (>17.0 A), specic surface area (S BET > 182 m 2 g À1 ), micropore surface area (S mp > 77.5 m 2 g À1 ), and improved thermal stability (up to 800 C).…”