Study on the Transport Properties of SO₂ and NO at the Interface of H₂O₂ Solutions Using Molecular Dynamics

Gas-liquid interfaces have a unique structure different from the bulk phase due to the complex intermolecular interactions within them and are regarded as barriers that prevent gases from entering solution or as channels that affect gas reactions. In this study, the adsorption and mass-transfer mechanisms of sulfur dioxide and nitric oxide at the gas-liquid interface of a H₂O₂ solution were comprehensively analyzed using molecular dynamics (MD) simulations. The analysis on molecule angle showed that H₂O molecules tended to align parallel to the solution surface on the surface of the H₂O₂ solution. Regardless of whether the gas was adsorbed on the surface of the solution or not, H₂O₂ molecules were always perpendicular to the interface of the solution. The analysis on molecule angle and radial distribution function revealed that the H atoms of H₂O molecules had a corresponding turn, and SO₂ molecules were greatly affected by the attraction of H₂O₂ molecules during the adsorption of gas molecules on the interface. Steered MD was utilized to investigate the mass-transfer process of SO₂ and NO molecules across the gas-liquid interface. The S atoms of SO₂ molecules were significantly influenced by H₂O₂ molecules, while the O atoms of NO molecules gradually transitioned from the gas phase to the liquid phase. The results provided information on how gas molecules interacted with the surface of the solution and the specific details of the molecular orientation at the solution surface.