Organic Exfoliation of Hydrophilic Bentonite using Aliquat 336 and Isobutyl(Trimethoxy)Silane to Enhance its Activity Toward pH-Dependent Adsorption of Epigallocatechin Gallate

Abstract

The most potent and significant polyphenolic molecule from tea catechins is epigallocatechin gallate (EGCG); it has potential anti-cancer and anti-inflammatory properties. Methods are needed to mitigate its presence in the environment and protect humans from exposure. The objective of the present study was to investigate a functionalized, low-cost clay mineral as an adsorbent for the tea polyphenol EGCG. Hydrophilic bentonite (Bn) was functionalized using Aliquat 336 (A336) and isobutyl(trimethoxy)silane (IBTS). The degree of clay functionalization depended on the extent of introduction of alkyl linkages between the superimposed clay layers. Results revealed that Aliquat 336 functionalized clay (A336-Bn) exhibited maximum thermal stability at 500°C and it is a promising adsorbent for ECGC with a maximum adsorption capacity of 196.26 mg/g at equilibrium. Experimental data were analyzed using pseudo-first order and pseudo-second order models. Adsorption isotherms were interpreted from the Freundlich adsorption isotherm.

Enhanced Retention of Cd(II) by Exfoliated Bentonite and Its Methoxy Form: Steric and Energetic Studies

“…Recent studies have established methoxy-modified clay-based frameworks as advanced forms of tailored clay, exhibiting enhanced adsorption properties. , Through the utilization of environmentally friendly grafting techniques, the hydroxyl groups present on the innermost surface of natural clay can undergo intercalation by alcohol molecules that exist under ambient conditions. − Previous studies have focused on investigating the technical aspects of methoxy-kaolinite, but there is a dearth of research on the properties of methoxy-bentonite. , The strategy of methoxy-kaolinite synthesis necessitates a preliminary treatment phase to mitigate the influence of hydrogen bonding present within the crystalline structure of kaolinite. This entails the utilization of additional chemicals and a number of experimental approaches. , In contrast to kaolin, montmorillonite exhibits a higher level of hydroxyl layer interchangeability, enabling the insertion of alcohol molecules within its layered structure.…”

“…This entails the utilization of additional chemicals and a number of experimental approaches. , In contrast to kaolin, montmorillonite exhibits a higher level of hydroxyl layer interchangeability, enabling the insertion of alcohol molecules within its layered structure. This characteristic facilitates the binding of methanol with no need for extra pretreatment steps. , Therefore, it was hypothesized that the incorporation of methanol into bentonite-layered subunits would result in the formation of a multifunctional hybrid framework with enhanced physicochemical properties . Moreover, during the past several decades, substantial advancements have been made in the field of the morphological transformation processes of clay, particularly in the area of separating or exfoliating the layered clay structures into discrete silicate sheets that possess two-dimensional geometrical structures. , The utilization of this approach has led to beneficial effects in the production of innovative nanostructures comprised of clay minerals, which demonstrate significant characteristics including considerable biological activity, adsorption potential, oxidation properties, surface reactivity, surface area, and dispersion properties. ,, Therefore, the formation of methoxy forms of the exfoliated bentonite nanosheets will result in highly promising adsorbents for a variety of soluble water pollutants.…”

“… 33 − 35 Previous studies have focused on investigating the technical aspects of methoxy-kaolinite, but there is a dearth of research on the properties of methoxy-bentonite. 32 , 36 The strategy of methoxy-kaolinite synthesis necessitates a preliminary treatment phase to mitigate the influence of hydrogen bonding present within the crystalline structure of kaolinite. This entails the utilization of additional chemicals and a number of experimental approaches.…”

“… 32 , 38 Therefore, it was hypothesized that the incorporation of methanol into bentonite-layered subunits would result in the formation of a multifunctional hybrid framework with enhanced physicochemical properties. 36 Moreover, during the past several decades, substantial advancements have been made in the field of the morphological transformation processes of clay, particularly in the area of separating or exfoliating the layered clay structures into discrete silicate sheets that possess two-dimensional geometrical structures. 39 , 40 The utilization of this approach has led to beneficial effects in the production of innovative nanostructures comprised of clay minerals, which demonstrate significant characteristics including considerable biological activity, adsorption potential, oxidation properties, surface reactivity, surface area, and dispersion properties.…”