There have been obtained and characterized ferruginous powders designed for the depollution of water containing arsenic. The powders have been obtained via combustion synthesis and iron salts decomposition, than analyzed in terms of phase composition, thermal analysis, surface area and adsorbent properties relative to As³⁺. The effect of SiO₂ and Al₂O₃ additions upon the adsorption capacity of the obtained materials has been pursued. It has been concluded that these materials may be successfully used in the depollution of underground waters with a high arsenic content.