Both inorganic and organic modified montmorillonite with diethylamine was used to adsorb N,N-dimethylaniline from water. The aim of this work was the use of montmorillonite clays, saturated first with sodium/potassium chloride and, second, exchanged with diethylamine, as a sorbent for purifying N,N-dimethylaniline contaminated water. Diethylamine was protonated in situ with HCl to obtain diethylammonium cations. Water and water/methanol mixture were used as reaction medium, and the ratios amine/clay and HCl/amine were also varied. Optimal results were obtained for an amine/clay ratio of 0.12 mmol/g. For a given amine/clay ratio, the HCl/amine ratio influences the interaction. The results will provide valuable information on using inorganic and organic modified montmorillonite for removing hazardous pollutants such as aromatic amines. The effect of pH and Na+/K+ exchange on the adsorptive behaviour of montmorillonite clay was examined.