Dynamic model of water vapor adsorption by mesoporous alumina-coated fabric

This work presents the experimental characterization and dynamic modeling of a novel mesoporous alumina‑coated fabric designed for water vapor adsorption. Alumina is a well‑established desiccant due to its high surface area, mesoporosity, and thermal stability, yet its integration into lightweight and flexible fabric structures remains insufficiently documented. To address this gap, the adsorption equilibrium of the alumina coating was first measured, showing limited temperature dependence and a transition from multilayer adsorption to capillary condensation at high relative humidity. Dynamic adsorption experiments were then conducted in a dedicated PVC ‑tube reactor under controlled temperature, humidity, and flow conditions using four fabric roll geometries. A 1‑dimensional dynamic model was developed based on coupled mass and heat balances in both the gas phase and the solid. The model incorporates equilibrium thermodynamics and interfacial transfer phenomena, and its parameters were estimated through Levenberg–Marquardt (1963) optimization using outlet humidity and temperature measurements. Results show that mass and heat transfer resistances are negligible under the tested conditions, leading to local thermodynamic equilibrium throughout the fabric. Model predictions agree well with experimental data, with deviations generally below 2%, except for extreme geometries where hydrodynamics is modelled less accurately. The atypical breakthrough shapes observed experimentally are attributed to the exothermicity of adsorption and the low thermal capacity of air, which limits heat dissipation and temporarily reduces adsorption capacity. The validated model provides a predictive tool for optimizing alumina‑coated fabrics in dehumidification applications and highlights the need for improved heat management in future designs.