Preparation of hectorite-like swelling silicate with controlled layer charge density

Abstract

Smectite like layered silicates with cation exchange capacity ranges from 60 to 90 mequivalent/100g clay were synthesized from LiF, Mg(OH)2 and colloidal silica. The controlled cation exchange capacity achieved by changing the composition of the starting mixture (namely the added LiF amount) successfully influenced the nanostructures of intercalation compounds prepared by the ion exchange with dioctadecyldimethylammonium ion.

Inorganic–Organic Interactions

“…The basal spacing, which corresponds to the inclination of the alkyl chains, should increase with the layer charge of clays ( Fig. 6.2 [25], which affected the spatial distribution of cationic guest distribution [26]. Ion exchange of the hectorite-like silicates with dioctadecyldimethylammonium (abbreviated as 2C 18 2C 2 N + ) resulted in paraffin-type arrangements of the intercalated 2C 18 2C 2 N + ( Fig.…”

“…In order to control the interlayer expansion, clays with different layer charge density [24][25][26][151][152][153][154][155] or alkylammonium ions with different molecular structures should be used. These may bring other factors such as different levels of impurity and variation of the particle size to affect the photoprocesses of the adsorbed species.…”

Photochromic Intercalation Compounds

“…Co.) [62,63], have advantages for the photochemical studies since natural clay minerals contain impurities, which gave colored clays. Synthetic analogues of smectite have been prepared in laboratory and used for the adsorption of dyes [19,[64][65][66][67].…”

Crystal architectures of a layered silicate on monodisperse spherical silica particles cause the topochemical expansion of the core-shell particles

“…[30][31][32][33][34] It has therefore been recognised that one of the advantages smectites offer (in addition to the many other important properties of smectites and their intercalation compounds) is that the CEC can be varied in order to control the spatial distribution of organic moieties. [35] Hectorite [36] and saponite [37] are layered clay minerals in the smectite family that have variable CECs. Hectorite and saponite have been synthesised for use precisely controlling cationic dye distributions [37] and adsorbing organic molecules.…”

“…[23,36,[65][66][67] The amount of intercalated alkylammonium ions can be deduced from changes in the basal spacings caused by the intercalating alkylammonium ions, the arrangement as a function of the layer charge density and the alkyl chain length. The arrangement will change from the parallel type (monomolecular, bimolecular and pseudo-trimolecular layers, with the alkyl chains parallel to the silicate layers) to the paraffin type in the interlayer space [67,68] as the layer charge density of a smectite is increased, as shown schematically in Fig.…”