Modification, hybridization and applications of saponite: An overview

Abstract

Modification of saponite (Sap) by surface engineering and intercalation chemistry introduces guest species into the structure of Sap and enhances the functionalities of the resultant Sap-based hybrids or composites. This review summarizes and evaluates latest scientific advances in the strategies for surface engineering, intercalation and hybridization of Sap, the insights into the relevant mechanisms, and the properties and applications of the resultant Sap-based materials. Studies have indicated that Sap can be inorganically modified by acid activation, inorganic cation exchange, pillaring, and adsorption. The methods of preparing organo-saponite (OSap) hybrids can be categorized as follows: 1) exchanging the inorganic cations in the interlayer space of Sap with organic cations; 2) covalent grafting of organic moieties or groups onto the surface of Sap; 3) intercalating polymer into the interlayer space of Sap by solution intercalation, and melt mixing or in situ polymerization. Organic-inorganic modified Sap can be made through the reactions between organic species and inorganic-modified Sap, or by the combination of inorganic species with organic-modified Sap. Modified Sap exhibits exceptional thermal stability, surface acidity, optical effects and adsorption. As such, the modified Sap can be used for optical materials, adsorbents, catalysts and clay/polymer nanocomposites (CPN). Literature survey suggests that future studies should place emphasis on optimizing and scaling up the modification of Sap, probing the thermodynamics, kinetics and mechanisms of the modification of Sap, endowing Sap with novel functionalities, and accordingly advancing the practical applications of the resultant Sap-based materials.

Physico-Chemical Characterization and Antimicrobial Properties of Hybrid Film Based on Saponite and Phloxine B

“…After the modification and functionalization with PS, it formed optically homogeneous and transparent films (see discussion below). This silicate, with its parameters such as particle size and layer charge, meets the criteria for the modification of polymer nanocomposites and controlled drug delivery [ 46 , 47 , 48 ]. Its layer charge can provide a static anchor to help with the proper distribution and assembly of different molecules, including those with photoactive properties [ 44 , 49 ], which was also confirmed in this study.…”

Using raw and thermally modified fibrous clay minerals as low concentration NH4+–N adsorbents

“…The intensity change of the reflections highlights the surficial interaction between adsorbent-adsorbate (Papoulis et al 2019), whereas the peak shifting can be attributed either to the ion exchange that took place or to the surficial bonding that may affect the crystallinity. Moreover, even the small presence of saponite may influence the surficial interactions with NH4 + , since saponite consists of multiple OHgroups on its surface (Zhou et al 2019).…”

Saponite-anthocyanin pigments: Slipping between the sheets

“…The structure of saponite is composed of a magnesium octahedral sheet sandwiched between two silicon tetrahedral sheets via sharing oxygen. Substitution of Si 4+ cations by Al 3+ where M is the exchangeable interlayer cation, x (0.2 ≤ x ≤ 1.2) is the fraction of aluminum present in Si-O tetrahedral sheets, and n is the number of water molecules [25,26].…”