Avaliação teórica da adsorção e degradação do agente neurotóxico Soman utilizando δ-FeOOH pura e modificada com nióbio

Abstract

The adsorption and degradation of the Soman molecule (Pinacolylmethylphosphonofluoridate, C7H16FO2P) was investigated using the pure and Nb-doped δ-FeOOH (001) surfaces with density functional theory (DFT) calculations. We verified the Soman molecule adsorbs on pure and doped surface due to interaction, mainly, between phosphoryl oxygen (P=O) and hydroxyl groups from surface. The degradation of the Soman molecule on the δ-FeOOH and Nb-δ-FeOOH (001) surfaces was evaluated by analysis of electronic energy and kinetics. By the theoretical calculations of the reaction path, was identified only one transition state for both surfaces, corresponding to a maximum stretch of F-P=O group from Soman molecule and the bond breaking of the hydroxyl group bonded to Fe/Nb.The activation energy found is 16.58 and 8.80 kcal/mol to pure and doped surface, respectively. The products were identified and characterized theoretically. Both δ-FeOOH and Nb-δ-FeOOH (001) surfaces show great potential to adsorb and degrade the Soman neurotoxic agent, however the presence of Nb can favor the process.