Batch and column adsorption of four pharmaceuticals, namely, tetracycline (TC), sulfamethoxazole (SMZ), nalidixic acid (NAD), and chloramphenicol (CHL) on ionic liquid modified montmorillonite (Mt-IL) was evaluated. The effects of variation in pH and contact time were analyzed and the data were fitted to kinetics and isotherm models. The equilibrium experimental data were best explained by the Freundlich model. A pseudo second-order kinetic model described all pharmaceuticals adsorbed on Mt-IL. In column studies, the exchange zone depth, adsorption capacity, the required time for the pharmaceuticals to move through the height of the adsorbent in the column, and adsorption rates were investigated by the Yoon-Nelson and the Thomas and Adams-Bohart models.