In this work, a new resin that can remove cationic dyes like Methylene Blue dye from aqueous solutions will be introduced. For this, novel kappa-carrageenan/polyvinyl alcohol hydrogel (kC/PVA) composites with modified pumice were made. Using the freezing-thawing procedure, the mixture of polymers and modified pumice was cross-linked, and then K+ ions were added. Using SEM, FTIR, and XRD methods, the structure of the resultant hydrogel composites was identified. Using a batch adsorption technique, the effects of contact time, changed pumice content, temperature, pH, ion strength, and dye solution salinity on the adsorption of cationic methylene blue dye on the hydrogel composites were examined. The swelling capacity of the resultant hydrogels was found to be lower than that of modified pumice-free hydrogels, falling from 780 to 470 %. The number of salts CaCl2 and AlCl3 in the solution dramatically reduced the adsorption capacity from 24.61 to 19 and 17 correspondingly. The greatest adsorption capacity of the hydrogel composites achieved was 185.65 mg g-1, and equilibrium dye adsorption data were also found to follow the Langmuir model. Based on the results of this study, synthetic hydrogel composites can be used as inexpensive adsorbents to remove colors from aqueous solutions, such as commercial dye baths.