Development and validation of a 1D gas–liquid model for dissolved Mn(II) removal by oxidation process in a square bubble column

•A comprehensive 1D model is developed to couple hydrodynamics, oxygen transfer and autocatalytic manganese oxidation.•The transient axial 1D model is applied to a bubble column used for Mn(II) removal.•A two bubbles class model is implemented to represent the heterogeneous regime.•Simulated parameters are in good agreement with experimental measurements and very close to 3D CFD results.•Transient 1D model and experimental data are in good agreement for several operating conditions after the first 15 min. Modeling multiphase reactors requires an in-depth multidisciplinary analysis of various phenomena including the chemical kinetics, oxygen mass transfer, as well as the simulation of flows within these contactors. In this study, a 1D model of two-phase flow for Mn(II) removal from drinking water by aeration process is developed and validated. This model is based on the Eulerian description of two-phase gas–liquid flow with the comparison between a one-medium bubble size and a two-bubble class description to represent the bubble population in the heterogeneous flow regime. All the relevant chemical species are simulated by coupling hydrodynamics, gas–liquid mass transfer, and reaction kinetic. A pseudo-first-order model accounting for homogeneous and heterogeneous kinetics is considered for Mn(II) oxidation. The performance of the developed 1D model is compared and validated with experimental data. The 1D model was able to predict quantitatively Mn oxidation as a function of pH, initial Mn(II) and initial Mn(IV) concentrations.