The removal of basic dye from aqueous solution was studied using Al2O3 modified frustule samples.The intrinsic exchange properties were further improved by modification with aluminum oxides.Modified adsorbent(referred to as Al-frustule)showed a higher tendency for adsorbing dye.The high performance exhibited by Al-frustule was attributed to increased surface area and higher negative surface charge after modification.Scanning electron microscope pictures revealed a birnessite structure of aluminum oxides.