Insight into the Effect of Sulfonation Techniques on the Adsorption Properties of −SO<sub>3</sub>H Surface-Functionalized Coal as Adsorbent for Malachite Green Dye: Steric and Energetic Investigation
Ali A. AlHammadi, Rania Nasser, Mohamed Shaban, Sarah I. Othman, Jong Seong Khim, Jamaan S. Ajarem, Ahmed A. Allam, Mostafa R. Abukhadra
Abstract
of N.C (121.3 mg/g), MS.C (226.3 mg/g), and SS.C (296.4 mg/g) validate the significant effect of the sulfonation processes by the sonication waves. This is in agreement with the active site densities that reflect the saturation of SS.C by more active sites (180.74 mg/g) than MS.C (120.38 mg/g) and N.C (70.84 mg/g). The MS.C and SS.C can adsorb three MG molecules as compared to two molecules per site of N.C. The Gaussian energy (<8 kJ/mol) and adsorption energy (<40 kJ/mol)) reflects the physisorption of MG involving van der Waals forces, hydrogen bonding, and dipole bonding forces. The thermodynamic functions demonstrate the uptake of MG by exothermic, spontaneous, feasible reactions.