Organobentonites were prepared using three cationic surfactants tetradecyl- (C14), hexadecyl- (C16) and octadecyltrimethylammonium (C18) bromides in the proportions of 100% and 200% of the cationic exchange capacity (CEC) at 323 K under microwave irradiation for 5 min. The XRD patterns indicated the formation of intercalated hybrids with d values in the range 1.83–2.00 nm. CHN elemental analysis showed better organofunctionalization of the clay matrix for the organobentonites obtained with 200% of the CEC and longer organic alkyl chains and agreed with thermogravimetric analysis. Infrared spectroscopy suggested the presence of the organic moieties on organobentonites, showing typical absorptions of CH2 and CH3 groups. The solids were applied for Remazol blue RN dye removal from a single and synthetic effluent sample. The influences of the pH, adsorbent dosage, contact time and initial dye concentration were systematically investigated. The data were fitted to different kinetic and equilibrium models. All of the adsorption processes were adjusted to pseudo-second order and Langmuir models. The organobentonites showed good performance in dye removal at a pH of 2 for the solids obtained with 100% of the CEC, and the dye removal was independent of the pH for the other solids, which is in agreement with the zeta potential measurements. The optimal reaction time was 60 min, except for Bent-C16-200%. The best dye removal efficiency (100%–211 mg g−1) for the Bent-C14-200% sample with 500 mg/L of dye concentration.