This work investigates the liquid-phase adsorption of n-butanol on Amberlyst (TM) 15 in the temperature range 295-323 K at different initial adsorbate concentrations. The adsorbent was characterized by N-2 physisorption, Fourier transform infrared adsorption of pyridine, scanning electron microscopy, and powder X-ray diffraction. The data obtained confirmed an adsorbent structure with two porosity levels and amorphous polymer structure. The active sites in Amberlyst (TM) 15 are of Bronsted or Bronsted-Lewis type. The liquid-phase adsorption equilibrium constants were determined at different temperatures from slurry adsorber experiments. The thermodynamic state functions were estimated and are consistent thermodynamically with physical adsorption. The macropore diffusion coefficients of n-butanol on Amberlyst (TM) 15 were estimated by using the moment technique, and the contribution of surface diffusion to the macropore diffusion coefficients was evaluated.