Reverse micro emulsion route with subsequent several heat-treatments was considered to synthesize ã and ï¡ ?alumina nanoparticles. The study clarified that metastable ã-Al2O3 phase was gross through the annealing temperature (650oC-900oC) with particle size ranged (2nm-4nm). The increase of temperature to more than 900oC, leads to a well formation of stable á-Al2O3 with particle size 80nm. The investigations confirmed that, ã-alumina is characterized by its great roughness, surface area and pore volume, while á-alumina is distinct by small porosity. These two alumina phases were tested in water detoxification. Their efficiency to remove lead from water was measured. The measurements indicated that the removal efficiency after 7h for ã and ï¡ï alumina reaches 94.5% and 92% respectively. These results together with the characteristic study of roughness and porosity recommended that ã-Al2O3 can be applied as catalyst support in adsorption of toxic heavy metals, while, á-Al2O3 can be used in fabrication of water desalination membrane.