The mass diffusivities for the samples were determined to be 4.47 ± .04 1010 m2/s (adsorption) and 9.06 ± .05 1010 m2/s
(desorption), and 8.57 ± .06 1010 m2/s (adsorption) and 12.79 ± .04 1010 (desorption) for ammonium hydroxide and
hydrofluoric acid catalysts, respectively.