Structural and thermal properties of inorganic–organic montmorillonite: Implications for their potential environmental applications

Abstract

Inorganic-organic clays (IOCs), clays intercalated with both organic cations such as cationic surfactants and inorganic cations such as metal hydroxy polycations have the properties of both organic and pillared clays, and thereby the ability to remove both inorganic and organic contaminants from water simultaneously. In this study, IOCs were synthesised using three different methods with different surfactant concentrations. Octadecyltrimethylammonium bromide (ODTMA) and hydroxy aluminium ([Al13O4(OH)24(H2O)12](7+) or Al13) are used as the organic and inorganic modifiers (intercalation agents). According to the results, the interlayer distance, the surfactant loading amount and the Al/Si ratio of IOCs strictly depend on the intercalation method and the intercalation agent ratio. Interlayers of IOCs synthesised by intercalating ODTMA before Al13 and IOCs synthesised by simultaneous intercalation of ODTMA and Al13 were increased with increasing the ODTMA concentration used in the synthesis procedure and comparatively high loading amounts could be observed in them. In contrast, Al/Si decreased with increasing ODTMA concentration in these two types of IOCs. The results suggest that Al-pillars can be fixed within the interlayers by calcination and any increment in the amount of ODTMA used in the synthesis procedure did not affect the interlayer distance of the IOCs. Overall the study provides valuable insights into the structure and properties of the IOCs and their potential environmental applications.

The Role of Dispersion Technique and Type of Clay on the Mechanical Properties of Clay/Epoxy Composites

“…Several reviews on polymer‐layered silicate nanocomposites have been published and can be found elsewhere . Most epoxy‐clay nanocomposites reported in the literature contain montmorillonite (MMT), which is classified as a 2:1 phyllosilicate, composed by the stacking of 1 nm thick layers formed by one alumina octahedral sheet sandwiched between two silica tetrahedral sheets, with lateral dimensions around 200–300 nm …”

“…[7][8][9] Most epoxyclay nanocomposites reported in the literature contain montmorillonite (MMT), which is classified as a 2:1 phyllosilicate, composed by the stacking of 1 nm thick layers formed by one alumina octahedral sheet sandwiched between two silica tetrahedral sheets, with lateral dimensions around 200-300 nm. [10] Montmorillonite belongs to the smectite group of clay minerals, and its layers are negatively charged due to the presence of impurities. Sodium, calcium, lithium, or other cations are normally present in the interlayer space to counterbalance these charges.…”

Ecocompatible Halloysite/Cucurbit[8]uril Hybrid as Efficient Nanosponge for Pollutants Removal

“…Many of them have strong sorption affinities, large specific surface areas and high cation exchange capacities. [5] Among the aluminosilicates, halloysite nanotubes (Al 2 Si 2 O 5 (OH) 4 ·2H 2 O) (HNTs) are special nano-geomaterials similar to commonly used platy kaolin that have garnered interest in material science due to their versatile advantages of biocompatibility, environmental friendliness, large surface area, high porosity, widely spreadable properties and tunable surface chemistry as well as low cost. Moreover, HNTs are nanomaterials not toxic to aqueous species as confirmed by several studies on the interaction of halloysite nanotubes with microscopic algae Chlorella pyrenoidosa, [6] fresh water ciliate protist Paramecium caudatum [7] and nematode Caenorhabditis elegans.…”

“…[19] Cucurbiturils (CB) are cyclic oligomers of glycoluril units which can exhibit host-guest chemistry like cyclodextrins. There are different homologues of cucurbiturils i. e., CB [5], CB [6], CB [7], CB [8], etc. These pumpkin shaped compounds have a sufficiently large hydrophobic internal cavity of~5.5 which is accessible through two carbonyl fringed hydrophilic portals of~4 diameters for strong interactions with hydrophobic molecules.…”

“…[21] For instance CB [7] was indicated as a drug delivery agent for the cancer drug, oxaliplatin. [22] It is also known that cucurbiturils can strongly bind to hydrocarbons; for example, CB [5] and CB [6] can hold small gas molecules, aliphatic and unsubstituted aromatic guests, while CB [7] can host a few substituted aromatic guests. Recently, it was demonstrated [23] that CB [8] cavity represents an efficient binding site for the photocontrolled inclusion of organic guest molecules.…”