Titration-Based Simplification of Zirconium Complex Reactions and Advection-Diffusion Simulation in Flow Cell

Abstract

In this study, we developed a reactive advection-diffusion simulation model for H2ZrF6 solutions by integrating titration-based equilibrium analysis with concentration field simulation in a flow cell model. Equilibrium constants of Zr complex reactions were identified from titration curves using Bayesian estimation, and key reactions were selected via model selection based on Akaike information criterion. The simplified reaction model effectively reproduced experimental data while reducing computational cost. This model was then incorporated into a a concentration field simulation of reactive advection-diffusion equation in a flow cell to analyze Zr complex behavior near the metal surface under laminar flow. Simulations at pH 3.5, 4.0, 4.5 revealed steep H+ gradients and localized accumulation of Zr(OH)4 near the surface, providing insight into the influence of pH on protective film formation.