A theoretical and experimental study of the adsorptive removal of hexavalent chromium ions using graphene oxide as an adsorbent

Abstract

This study is focused on the adsorption of hexavalent chromium ions Cr(vi) using graphene oxide (GO). The GO was prepared by chemical oxidation (Hummers method) of graphite particles. The synthesized GO adsorbent was characterized by Fourier transform infrared spectroscopy and UV-Vis spectroscopy. It was used for the adsorption of Cr(vi) ions. The theoretical calculations based on density functional theory and Monte Carlo calculations were used to explore the preferable adsorption site, interaction type, and adsorption energy of GO toward the Cr(vi) ions. Moreover, the most stable adsorption sites were used to calculate and plot noncovalent interactions. The obtained results are important as they give molecular insights regarding the nature of the interaction between GO surface and the adsorbent Cr(vi) ions. The found adsorption energy of −143.80 kcal/mol is indicative of the high adsorptive tendency of this material. The adsorption capacity value of GO toward these ions is q = 240.361 mg/g.

An experimental and theoretical analysis of supercritical carbon dioxide extraction of Cu(II) and Pb(II) ions in the form of dithizone bidentate complexes

“…The evaluation of the interaction nature in the formed structures of dithizone complexes is performed via the NCI surface plot and the reduced density gradient (RDG) vs. sign (λ) (Figure 2) [15,31]. The greenish-blueish coloured surface and the spikes with negative sign (λ) values in the 2D NCI plot support that the van der Waals interactions are presented in the formed complex [20,24,32]. It is evident from the NCI plot that these interactions are more strongly present in the Pb(II)/dithizone complex-which is also supported by the interaction energy of this system compared to Cu(II) ions.…”

“…The adsorption energy, is evaluated using the well-known method [20][21][22]. The noncovalent interaction (NCI) was calculated using Multiwfn software [23] [24]. The NCI surface is plotted using the Visual Molecular Dynamics software [25].…”

Application of Taguchi method, response surface methodology, DFT calculation and molecular dynamics simulation into the removal of orange G and crystal violet by treated biomass

“…The interaction energy, both, in vacuum is evaluated as follow [ [40] , [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] ]: where E Adsorbent/CV or OG is the total energy of the adsorption system. E Adsorbent and E CV or GO are the energies of the isolated CV or GO and adsorbent respectively.…”

Oxygen Interactions with Covalently Grafted 2D Nanometric Carboxyphenyl Thin Films—An Experimental and DFT Study

“…To understand the adsorption details of the oxygen molecule onto the bare and CPgrafted gold surface, the NCI 2D and 3D plots [40,41] for the interaction of O 2 molecule with both surfaces were computed (Figure 8). The result confirms that adsorption proceeds through van der Waals interactions (cf.…”