The effect of advection on the adsorption kinetics of ammonia onto a polyaniline-sensitive surface in channel flow

• Improved the understanding of adsorption mechanisms applied to a sensitive surface. • Linked global to local adsorption observations around sensitive material. • Introduced a novel ratio (ACC) for NH 3 adsorption efficiency. • Dimensionless numbers (Da, Pe) generalized adsorption dynamic across potential setups. This numerical study investigates the effect of advection on NH 3 adsorption kinetics onto a doped Polyaniline (PAni) sensitive surface in channel flow, under diffusion-limited conditions characterized by a high Damköhler number. The effects of various parameters, such as gas inlet velocity, NH 3 concentration, and channel height, are tested and discussed. Results show that increasing channel height increases equilibrium time, while higher flow velocity reduces it. Local-scale analysis indicates that adsorption primarily occurs upstream and downstream of the sensitive surface initially, creating a depleted zone in between. An Adsorption Capacity Coefficient (ACC) is introduced to evaluate adsorption efficiency, revealing an inverse relationship between equilibrium time and efficiency. This study enhances the understanding of adsorption mechanisms by emphasizing the balance between diffusion and advection. These findings could be extended to other gases and sensitive materials, optimizing adsorption processes in various applications.