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ORIGINAL RESEARCH article
Front. Chem.
Sec. Solid State Chemistry
Volume 12 - 2024 |
doi: 10.3389/fchem.2024.1455838
Physicochemical, steric, and energetic characterization of kaolinite based silicate nano-sheets as potential adsorbents for safranin basic dye: Effect of exfoliation reagent and techniques
Provisionally accepted- 1 Beni-Suef University, Beni-Suef, Egypt
- 2 Imam Muhammad ibn Saud Islamic University, Riyadh, Saudi Arabia
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 to 29 kJ/mol), electrostatic attraction (2-50 kJ/mol), van der Waals forces (4 to 10 kJ/mol), and hydrogen bonding (<30 kJ/mol)
Keywords: Kaolinite, Exfoliation, intercalating agent, Safranin, Adsorption, advanced equilibrium
Received: 01 Jul 2024; Accepted: 09 Sep 2024.
Copyright: © 2024 Ali, Mohamed, Abdel-Khalek, Ahmed and Abukhadra. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Mostafa Abukhadra, Beni-Suef University, Beni-Suef, Egypt
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