A high-capacity cationic hydrogel adsorbent (CHA) was prepared by polycondensation using triethylenetetramine, acetone and formaldehyde as raw materials. Batch and fixed-bed column experiments were conducted to investigate the adsorption of Acid Black 1 from aqueous solution by CHA. The adsorption mechanism was discussed with respect to its characteristics. Experimental results showed that the adsorption was attributed to a combination of electrostatic attraction and intermolecular interactions between the functional groups of the hydrogel and the dye. The high adsorption capacity of CHA was due to its high cationic charge density and abundant functional groups. Langmuir isotherm fitted well to the equilibrium data and the adsorption process followed pseudo-second-order and intraparticle diffusion kinetic models. The diffusion of dye molecules inside the hydrogel was found to govern the mass transfer process. Good adsorption performance was also observed in the continuous column experiments. The adsorption capacity increased with increasing bed height and decreased with increasing feed flow rate. Overall, the results reported here indicated that CHA could be used as a promising adsorbent for the removal of anionic dyes from wastewater. (C) 2016 Elsevier B.V. All rights reserved.