Exploration of interfacial chemistry and physical movement in fixed-bed adsorption/desorption of anthocyanins with and without in-process ultrasonication.

The fundamental physics underlying the fixed-bed adsorption and desorption of anthocyanins was systematically investigated, both with and without in-process ultrasonication. A novel self-assembled fixed-bed system was designed by compacting macroporous resins and coupling the setup with ultrasound. The adsorption and desorption of chokeberry anthocyanins were quantitatively simulated using a phenomenological model that incorporated convection-dispersion in the axial flow and intraparticle diffusion within the resin matrix. Results revealed that fixed-bed performance was primarily governed by convection and dispersion in the bulk fluid, interfacial mass transfer at the resin-liquid boundary, intraparticle diffusion, and the number of binding sites between anthocyanins and the resin. Higher adsorption and desorption rates were observed when bulk convection and dispersion weakened, while interfacial mass transfer and intraparticle diffusion were enhanced. In-process ultrasonication did not significantly alter overall adsorption-desorption efficiency; however, it moderately intensified bulk liquid convection and dispersion, thereby reducing the extent of anthocyanin-resin binding. Overall, this modeling study provides mechanistic insights into anthocyanin purification via fixed-bed elution, offering new strategies for optimizing and controlling adsorption-based separation processes.