Comparative parametric study on development of porous structure of aluminium oxide in presence of anionic and cationic surfactants

Aluminium oxide was prepared from aluminium nitrate by precipitation in presence of cationic cetyl trimethyl ammonium bromide (CTAB) and anionic sodium dodecyl sulfate (SDS) surfactants. Effects of surfactant type and concentration, pH, aging temperature and aging time on development of porous structure of aluminium oxide were investigated and compared. Surface area of samples prepared with CTAB was higher compared to that prepared with SDS at all preparation conditions. Mainly mesopores were obtained with SDS, whereas in presence of CTAB micropores were also obtained, particularly at lower surfactant concentration. The bayerite and boehmite were predominant structures in presence of CTAB and SDS, respectively. Formation of mesopores was favored at higher pH in presence of SDS and at lower pH in presence of CTAB. Surface area and pore volume of aluminium oxide increased with aging time in presence of SDS, but the effect was not significant for CTAB.