Acid activated clays: Materials in continuous demand

Experimental Study of Montmorillonite Structure and Transformation of Its Properties under Treatment with Inorganic Acid Solutions

“…Alterations in FTIR data revealed as decreasing intensities of the bands related to octahedral Al, Fe and Mg and exchangeable Ca, Na and Mg correlate with changes in chemical composition shown above. Therefore, the structural units comprised of the tetrahedral sheet fragments are released from the 2:1 structure, which corresponds to "Si-O free " vibrations-1095 cm −1 [11,15,21,50]. Changes in the Si-O-Si band profile within the range of 1100-1050 cm −1 (Figure 2b) indicate transformation of interaction within the tetrahedral sheet.…”

Acid‐treated Bentonite as filler in the development of novel composite PVA hydrogels

“…At the same time, acid treatment leaves a large number of silanol groups (SiOH) on the active adsorbent sites . The extent of these processes depends on the experimental conditions of the acid treatment . In this work, the reaction was performed in mild conditions due to the fact that it was carried out at room temperature.…”

“…In this way, the specific surface area and surface acidity properties of the clay minerals can be greatly increased by acid activation . The extent of these changes will depend on different parameters such as the nature of the clay, the type of the used acid, and the reaction conditions …”

“…24 The extent of these changes will depend on different parameters such as the nature of the clay, the type of the used acid, and the reaction conditions. 25,26 The objectives of this study are to investigate the effect of the addition of an acid-treated bentonite on the structure and properties of PVA hydrogels and to explore the application of the resulting nanocomposite hydrogels for organic dyes adsorption. It is important to point out that to the best of our knowledge, the here obtained and characterized composite hydrogels (containing acid-modified bentonite as filler) have not been previously described.…”

Influence of Food with High Moisture Content on Oxygen Barrier Property of Polyvinyl Alcohol (PVA)/Vermiculite Nanocomposite Coated Multilayer Packaging Film

“…It is also possible that the simulant penetrating the film was dissociated by AA at the surface and edge of the vermiculate, which was likely to come into direct contact. Acid can dissociate inorganic oxides from vermiculite by chemical reaction (Komadel ), which is possible from the edge of vermiculite even in relatively weak 3% AA. From Kupková and others’ study, acid was effective at leaching Mg 2+ cations from the smaller vermiculite platelet along with Fe 2+ from the octahedral sheet and Al 3+ from the tetrahedral sheet of other vermiculite (Kupkova and others ).…”