Instantaneous Adsorption of Synthetic Dyes from an Aqueous Environment Using Kaolinite Nanotubes: Equilibrium and Thermodynamic Studies

Mostafa R Abukhadra; Merna Mostafa; Ahmed M El-Sherbeeny; Mohammed A El-Meligy; Ahmed Nadeem

doi:10.1021/acsomega.0c05430

Instantaneous Adsorption of Synthetic Dyes from an Aqueous Environment Using Kaolinite Nanotubes: Equilibrium and Thermodynamic Studies

ACS Omega. 2020 Dec 23;6(1):845-856. doi: 10.1021/acsomega.0c05430. eCollection 2021 Jan 12.

Authors

Mostafa R Abukhadra^{1

2}, Merna Mostafa^{1

2}, Ahmed M El-Sherbeeny³, Mohammed A El-Meligy⁴, Ahmed Nadeem⁵

Affiliations

¹ Geology Department, Faculty of Science, Beni-Suef University, Beni-Suef City 65211, Egypt.
² Materials Technologies and Their Applications Lab, Geology Department, Faculty of Science, Beni-Suef University, Beni-Suef City 62521, Egypt.
³ Industrial Engineering Department, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia.
⁴ Advanced Manufacturing Institute, King Saud University, Riyadh 11421, Saudi Arabia.
⁵ Department of Pharmacology & Toxicology, College of Pharmacy, King Saud University, Riyadh 12372, Saudi Arabia.

Abstract

Innovative kaolinite nanotubes (KNTs) are synthesized utilizing a simple technique involving a sonication-induced exfoliation process, followed by chemical scrolling reactions. The KNTs as a material have high reactivity and promising surface area to be used in the purification of water from cationic dyes (safranin (SF) and malachite green (MG)) and anionic dyes (methyl orange (MO) and Congo red (CR)). The kinetic studies of the four dyes SF, MG, CR, and MO show an equilibration time interval of 240 min. The SF, MG, CR, and MO dyes' uptake reactions are in agreement with the kinetic behavior of the pseudo-first-order model and the equilibrium properties of the Langmuir model. Such modeling results, in addition to the Gaussian energies from the Dubinin-Radushkevich (D-R) model (SF (1.01 kJ/mol), MG (1.08 kJ/mol), CR (1.11 kJ/mol), and MO (1.65 kJ/mol)), hypothesize monolayer adsorption of the four dyes by physical reactions. The KNTs show theoretical q _max values of 431.6, 489.9, 626.2, and 675.5 (mg/g) for SF, MG, CR, and MO, respectively. The thermodynamic examination of SF, MG, CR, and MO adsorption reactions using KNTs verifies their adsorption by exothermic and spontaneous reactions. The KNT adsorbents achieve promising adsorption results in the presence of different coexisting ions and show significant recyclability properties. Therefore, the production of KNTs from kaolinite shows a strong effect on inducing the textural, physicochemical, and adsorption properties of clay layers as well as their affinity for different species of synthetic dyes.