The role of water in the adsorption of Nitro-organics pollutants on Activated Carbon

13 pags, 6 figs., 6 tabs.Density functional theory (DFT) is applied to theoretically study the capture and storage of three different nitro polycyclic aromatic hydrocarbons, 4-Nitrophenol, 2-Nitrophenol and 9-Nitroanthracene by activated carbon, with and without the presence of water. These species are pollutants derived from vehicles and industry emissions. The modeling of adsorption is carried out at the molecular level using high level density functional theory with the B3LYP-GD(BJ)/6-31+G(d,p) level of theory. The adsorption energies of polluting gases considered isolated and in a humid environment are compared to better understanding the role of water. The calculations reveal different possible pathways involving the formation of chemicals bonds between adsorbent and adsorbate on the formation of intermolecular Van der Waals interactions. The negative adsorption energy on AC for the three species is obtained when they are treated individually and in mixture with H2O. The basis-set superposition error, estimated using the counterpoise correction, varies the adsorption energies by 2 to 13%. Dispersion effects were also taken into account. The adsorption energy ranges from -10 kJ/mol to -414 kJ/mol suggesting a diversity of pathways. The resulting analysis suggests three prefered pathways for catupre. The main pathway is physical interaction due to ¿-¿ stacking. Other means are capture due to the formation of hydrogen bonds resulting from water adsorbed on the surface, and the simultaneous adsorption of pollutant and water where water can act as a link that promotes adsorption. The thermodynamic properties give a clue to the most eco-friendly approaches for molecular adsorption.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 872081”. The authors acknowledge the Ministerio de Ciencia, Innovación y Universidades of Spain through the grants PID2020-112887GB-I00 and PID2020-113084GB-I00. The author acknowledges the CTI (CSIC) and CESGA and to the “Red Española de Computación” for the grant RES-AECT-2022-3-0006 and for computing facilities

Structural Diversity Within the Series of 68-Electron M4LnE2 (L = 2-Electron Ligand; M = Fe, Ru, Os, Co; E = CH, N, P, NR, PR, S) Organometallic Clusters: A Theoretical Investigation

International audienceFour different skeletal structural arrangements with very different connectivities are known for 6-vertex/68-electron of M4E2 core (M = transition metal; E = main-group atom or ligand). DFT calculations on a large number of title model compounds allow to rationalize the preferences between these structural shapes with respect to the nature of the metal and main-group elements constituting the cluster cage. In particular, the electronegativity of M and the "size" (first-row vs. second-row element) of E play an important role in the stability preference of a particular isomer. For several compounds, although only one type of structure is known, other low-energy isomeric forms are also likely to exist. Moreover, two structural types, so far unreported, are predicted to be stable enough for being synthesized