Engineering the Structures of Nanoporous Clays with Micelles of Alkyl Polyether Surfactants

Abstract

Composite clay nanostructures (CCNs) were observed in intercalating Laponite clay with alumina in the presence of alkyl polyether surfactants which contain hydrophobic alkyl chains and ether groups. Such nanostructured clays are highly porous solids consisting of randomly orientated clay platelets intercalated with alumina nanoparticles. The pores in the product solids are larger than the dimension of the surfactant molecules, ranging from 2 to 10 nm. This suggests that the micelles of the surfactant molecules, rather than the molecules, act as templates in the synthesis. Interestingly, it is found that the size of the framework pores was directly proportional to the amount of the surfactants in terms of moles, but shows no evident dependence on the size of the surfactant molecules. Broad pore size distributions were observed for the product CCNs. This study demonstrates that introducing surfactants in the pillaring process of clays is a powerful strategy for tailoring the pore structures of nanoporous clays. With this new technique, it is possible to design and engineer such composite clay nanostructures with desired pore and surface properties by the proper choice of surfactant amounts and preparation conditions.

Synthetic clay nanocomposite‐based coatings prepared by UV‐cure photopolymerization

“…40 The difficulty in observing a sharp diffraction peak for the pure clay is attributed to the very small (20 -30 nm) diameter of the clay platelets and to the poor longrange order caused by the aggregation of these platelets. 41 The diffraction peak shifted 2 ϭ 5.6°for the organically modified clay (OML) [ Fig. 7(b)], signifying an increase of the interlayer distance of the clay sheets to 1.58 nm, whereas an increase to 2.14 nm was observed for the laponite plus Jeffamine [ Fig.…”

Discoloration and mineralization of Orange II by using Fe3+-doped TiO2 and bentonite clay-based Fe nanocatalysts

“…Nanostructured materials have been developed and employed as heterogeneous catalysts for various applications including the remediation of water and air [1][2][3][4][5][6][7][8][9][10][11][12][13][14] by photocatalysis and photo-Fenton reaction. Photocatalysis is based on photogenerated electrons (e À ) and holes (h + ) migrating to the catalyst surface, reacting with adsorbed pollutants and resulting in the degradation of the pollutants.…”

“…Apart from TiO 2 nanostructured catalysts, clay-based nanostructured catalysts have also been developed for both water and air remediation [9][10][11][12][13][14]. For example, Feng et al [11][12][13][14] Their results illustrate that both nanocatalysts exhibited optimal photocatalytic activity at an initial solution of pH 3.0, which is the optimal pH for homogeneous and heterogeneous photo-Fenton reactions [15][16][17][18].…”

Selective catalytic oxidation of H2S over iron oxide supported on alumina-intercalated Laponite clay catalysts

“…However, in the small angle XRD patterns, no peaks can be observed for the host clay, AL-Lap and all catalysts, which can be attributed to the small platelets of host clay (about 20-30 nm in diameter) and lack of long-range order [14]. In order to further investigate the structure of Fe/Al-Lap catalysts, FTIR technology was applied.…”

“…Herein, a good method was developed to synthesize aluminaintercalated Laponite clay composites with mesoporous structures and high thermal stability in the presence of surfactants [14,15]. In consequence, the composites can be widely used as catalyst supports.…”