Insight into the Morphological Properties of Nano-Kaolinite (Nanoscrolls and Nanosheets) on Its Qualification as Delivery Structure of Oxaliplatin: Loading, Release, and Kinetic Studies

Physicochemical, steric, and energetic characterization of kaolinite based silicate nano-sheets as potential adsorbents for safranin basic dye: effect of exfoliation reagent and techniques

Kaolinite was subjected to advanced exfoliation processes to form separated nano-silicate sheets (EXK) with enhanced physicochemical properties as adsorbents. This involved the incorporation of different exfoliating agents, urea (U/EXK), KNO3 (N/EXK), and CTAB (C/EXK), highlighting their impacts on their textural and surficial properties as adsorbents for safranin dye. The applied characterization techniques confirmed the higher exfoliating degree of C/EXK, followed by N/EXK and U/EXK. This appeared significantly in the determined surface area (55.7 m2/g (C/EXK), 36.7 m2/g (U/EXK), and 47.1 m2/g (N/EXK)) and adsorption performances. The C/EXK structure displayed a better safranin uptake capacity (273.2 mg/g) than N/EXK (231 mg/g) and U/EXK (178.4 mg/g). Beside the remarkable differences in textural properties, the advanced mathematical modeling and the corresponding steric and energetic parameters illustrate the mentioned uptake properties. The interface of C/EXK is highly saturated by active uptake sites (Nm = 158.8 mg/g) as compared to N/EXK (109.3 mg/g) and U/EXK (93.4 mg/g), which is in agreement with the characterization findings and the expected higher exposure of siloxane groups. Each of these sites can be filled with four dye molecules using C/EXK and N/EXK, which implies the vertical orientation of these adsorbed ions and the effective operation of multi-molecular mechanisms. The energetic (ΔE < 40 kJ/mol) and thermodynamic investigations indicate the spontaneous, physical, and exothermic uptake of safranin molecules by EXK particulates. These mechanisms might involve dipole bonding (2-29 kJ/mol), electrostatic attraction (2-50 kJ/mol), van der Waals forces (4-10 kJ/mol), and hydrogen bonding (<30 kJ/mol).

Enhanced remediation of U(vi) ions from water resources using advanced forms of morphologically modified glauconite (nano-sheets and nano-rods): experimental and theoretical investigations

Two forms of morphologically transformed glauconite (GL) involved exfoliated nanosheets (EXG) and nanorods (GRs), which were synthesized by facile exfoliating and scrolling modification under sonication. The two advanced forms (EXG and GRs) were applied as enhanced adsorbents for U(vi) ions and compared with using raw glauconite. The developed GRs structure displays higher saturation retention properties (319.5 mg g-1) in comparison with both EXG (264.8 mg g-1) and GL (237.9 mg g-1). This enhancement is assigned to the noticeable increment in the surface area (32.6 m2 g-1 (GL), 86.4 m2 g-1 (EXG), and 123.7 m2 g-1 (GRs)) in addition to the surface reactivity and exposure of effective siloxane groups. This was supported by the steric investigation based on the isotherm basics of the monolayer model of one energy site. The steric functions declared a strong increase in the density of the existing effective uptake receptors throughout the modification stages (GRs (112.1 mg g-1) > EXG (87.7 mg g-1) > 72.5 mg g-1 (GL)). Also, each active site can be filled with 4 U(vi) ions, donating the parallel orientation of these ions and the operation of multi-ionic mechanisms. The energetic functions, either the uptake energy (<13 kJ mol-1) or Gaussian energy (<5 kJ mol-1), validate the retention of U(vi) by physical reactions. These reactions displayed spontaneous properties and exothermic behaviors based on the investigated thermodynamic functions, including entropy, enthalpy, and internal energy. The structures also showed significant recyclability, indicating potential application on a realistic and commercial scale.

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

Synergistic studies were conducted to evaluate the retention potentiality of exfoliating bentonite (EXBEN) as well as its methanol hybridization derivative (Mth/EXBEN) toward Cd(II) ions to be able to verify the effects of the transformation processes. The adsorption characteristics were established by considering the steric and energetic aspects of the implemented advanced equilibrium simulation, specifically the monolayer model with a single energy level. Throughout the full saturation states, the adsorption characteristics of Cd(II) increased substantially to 363.7 mg/g following the methanol hybridized treatment in comparison to EXBEN (293.2 mg/g) as well as raw bentonite (BEN) (187.3 mg/g). The steric analysis indicated a significant rise in the levels of the active sites following the exfoliation procedure [retention site density (Nm) = 162.96 mg/g] and the chemical modification with methanol [retention site density (Nm) = 157.1 mg/g]. These findings clarify the improvement in the potential of Mth/EXBEN to eliminate Cd(II). Furthermore, each open site of Mth/EXBEN has the capacity to bind approximately three ions of Cd(II) in a vertically aligned manner. The energetic investigations, encompassing the Gaussian energy (less than 8 kJ/mol) plus the adsorption energy (less than 40 kJ/mol), provide evidence of the physical sequestration of Cd(II). This process may involve the collaborative impacts of dipole binding forces (ranging from 2 to 29 kJ/mol) and hydrogen binding (less than 30 kJ/mol). The measurable thermodynamic functions, particularly entropy, internal energy, and free enthalpy, corroborate the exothermic and spontaneous nature of Cd(II) retention by Mth/EXBEN, as opposed to those by EXBEN and BE.

Effective retention of cesium ions from aqueous environment using morphologically modified kaolinite nanostructures: experimental and theoretical studies

Kaolinite can undergo a controlled morphological modification process into exfoliated nanosilicate sheets (EXK) and silicate nanotubes (KNTs). The modified structures were assessed as potential effective adsorbents for the retention of Cs+ ions. The impact of the modification process on the retention properties was assessed based on conventional and advanced equilibrium studies, considering the related steric and energetic functions. The synthetic KNTs exhibit a retention capacity of 249.7 mg g-1 as compared to EXK (199.8 mg g-1), which is significantly higher than raw kaolinite (73.8 mg g-1). The kinetic modeling demonstrates the high effectiveness of the pseudo-first-order kinetic model (R2 > 0.9) to illustrate the sequestration reactions of Cs+ ions by K, EXK, and KNTs. The enhancement effect of the modification processes can be illustrated based on the statistical investigations. The presence of active and vacant receptors enhanced greatly from 19.4 mg g-1 for KA to 40.8 mg g-1 for EXK and 46.9 mg g-1 for KNTs at 298 K. This validates the significant impact of the modification procedures on the specific surface area, reaction interface, and reacting chemical groups' exposure. This also appeared in the enhancement of the reactivity of their surfaces to be able to uptake 10 Cs+ ions by KNTs and 5 ions by EXK as compared to 4 ions by kaolinite. The thermodynamic and energetic parameters (Gaussian energy < 8.6 kJ mol-1; uptake energy < 40 kJ mol-1) show that the physical processes are dominant, which have spontaneous and exothermic properties. The synthetic EXK and KNT structures validate the high elimination performance of the retention of Cs+ either in the existence of additional anions or cations.

Synthesis and Characterization of Iron-Rich Glauconite Nanorods by a Facile Sonochemical Method for Instantaneous and Eco-friendly Elimination of Malachite Green Dye from Aquatic Environments

Novel glauconite nanorods (GNRs) were synthesized by the sonication-induced chemical expansion and scrolling process of natural glauconite. The synthetic nanostructure was characterized by different analytical techniques as a superior adsorbent for the malachite green dye (MG). The synthetic GNRs were detected as porous nanorods with an average length of 150 nm to 5 μm, an average diameter of 25 to 200 nm, and a specific surface area of 123.7 m2/g. As an adsorbent for MG, the synthetic GNRs showed superior uptake capacity up to 1265.6 mg/g at the saturation stage, which is higher than most of the recently developed highly adsorbent dyes. The adsorption behavior and mechanistic properties were depicted by using modern and traditional equilibrium modeling. The kinetic assumption of the pseudo-first-order model (R2 > 0.94) and the classic isotherm of the Langmuir equilibrium model (R2 > 0.97) were used to describe the adsorption reactions. The steric investigation demonstrates that each active site on the surface of GNRs can adsorb up to three MG molecules (n = 2.19-2.48) in vertical orientation involving multimolecular mechanisms. Also, the determined active site density (577.89 mg/g) demonstrates the enrichment of the surface of GNRs with numerous adsorption receptors with strong affinity for the MG dye. The energetic study, including Gaussian energy (6.27-7.97 kJ/mol) and adsorption energy (9.45-10.43 kJ/mol), revealed that GNRs had physically adsorbed the dye, which might involve electrostatic attraction, hydrogen bonding, van der Waals forces, and dipole forces. The internal energy, enthalpy, and entropy determined the exothermic and spontaneous uptake of MG.

Advanced Equilibrium Modeling for the Synergetic Effect of β-Cyclodextrin Integration on the Adsorption Efficiency of Methyl Parathion by β-Cyclodextrin/Exfoliated Kaolinite Nanocomposite

Exfoliated kaolinite nanosheets (EXK) and their hybridization with β-cyclodextrin (β-CD/EXK) were evaluated as potential-enhanced adsorbents of methyl parathion (MP) in synergetic investigations to determine the effects of the different modification procedures. The adsorption behaviors were described on the basis of the energetic steric and energetic factors of the specific advanced equilibrium models (monolayer model of one energy). The functionalization process with β-CD enhanced the adsorption behaviors of MP considerably to 350.6 mg/g in comparison to EXK (291.7 mg/g) and natural kaolinite (K) (244.7 mg/g). The steric studies revealed a remarkable improvement in the quantities of the existing receptors after exfoliation (Nm = 134.4 mg/g) followed by β-CD hybridization (Nm = 162.3 mg/g) as compared to K (75.7 mg/g), which was reflected in the determined adsorption capacities of MP. Additionally, each active free site of β-CD/EXK can adsorb about 3 molecules of MP, which occur in a vertical orientation by types of multimolecular mechanisms. The energetic investigations of Gaussian energy (<8.6 kJ/mol) and adsorption energy (<40 kJ/mol) validate the physical adsorption of MP, which might involve the cooperation of dipole bonding forces, van der Waals, and hydrogen bonding. The properties and entropy values, free enthalpy, and intern energy as the investigated thermodynamic functions declared the exothermic and spontaneous behaviors of the MP adsorption.