<p>This study investigated the adsorption of Congo red dye on alginate and chitosan hydrogel in batch and continuous modes. The purpose of this study was to evaluate alginate and chitosan hydrogel beads, with and without modifications, for the adsorption of Congo red dye in batch and continuous systems. In batch mode, activated charcoal and microalgal cells were embedded in the alginate and chitosan hydrogel beads. The results were compared against unmodified hydrogel beads, bare charcoal powder, and free microalgal cells. The highest dye removal efficiency was 96.99 ± 0.6% at 80 mg L⁻¹ with chitosan hydrogel obtained in batch. Kinetic study suggested pseudo-second order and intraparticle diffusion model for adsorption. Langmuir and Freundlich isotherm models were found to fit the dye adsorption into chitosan and alginate-based hydrogels, respectively. Later, in continuous study, chitosan hydrogels showed more than 75% dye removal efficiency for all initial concentrations. Moreover, increased adsorption capacity for all the initial concentrations was observed in a continuous range from 0.032 to 0.4&#xa0;mg/g. The findings support the utilization of chitosan-based hydrogels for industrial dye treatment after further optimization.</p>