Measurements of the pore structure of alumina (Neobead C) were investigated. The pore structure was measured by nitrogen adsorption-desorption and mercury penetration technique. The pore size distribution was calculated from the nitrogen adsorption-desorption isotherm data by the Cranston-Inkley method, the Barrett-Joyner-Halenda method and the Modelless method.
The surface area was determined by the B. E. T. method and the t method (the thickeness method). Result obtained were as follows: (1) The sample M (dp: 605 microns) was shown to be smaller amounts of adsorption of nitrogen over whole range of the relative pressure than that of the powdered sample S (dp: 58.5 microns). It is considered that the difference of the time consumed for a equilibrium adsorption, depends on that of particle size. (2) The surface area SBET obtained by B. E. T. method coincided well with the surface area St by the t method for powder sample S. (3) From the fact of plotting on a adsorption volume against the relative pressure being linear in the low relative pressure range, it is suggested that the multilayer of gas adsorption must be formed at the lower relative pressures. (4) The pore size distribution calculated from the nitrogen adsorption-desorption isotherm by each method was not so much different with each other. (5) The pore size distribution calculated from the nitrogen adsorption isotherm was largely different from that of the nitrogen desorption isotherm. The pore size distribution obtained by the mercury penetration method was markedly different from the branch of compression or the branch of depression in the penetration curve. (6) The pore size distribution of the aggregate of glass beads measured by the mercury penetration method was similar to that of alumina.
