Nitrogen adsorption at ca. 77.4 K on partially hydrated and anhydrous α-Al ₂ O ₃

N ₂ adsorption isotherms at ca. 77 K on macroporous α-Al ₂ O ₃ have been measured and analyzed in the frameworks of the classic thermodynamic approach, with independent experimental data obtained by means of SEM-EDX, XRD, TGA, helium pycnometry, and mercury porosimetry taken into account. It is shown, that presence of adsorbed water considerably influences N ₂ adsorption, which gradually increases with temperature of the degas treatment. Simultaneously, the shape of the isotherms has a trend to change from Type II to Type VI, that assumes changing of adsorption mechanism from progressive increasing of the adsorbed layer thickness towards layer-by-layer adsorption. Corrected and smoothed isotherms are presented in the tabular form as reference for subsequent more comprehensive analysis using molecular statistical approaches.