Activated coal obtained from mango residues is an alternative for the valorisation of these wastes for applications. This work focuses on the production of a new adsorbent from mango residues collected in the urban common of Mamou (Republic of Guinea) by chemical activation with potassium hydroxide. To do this, the different rates: humidity, cinders, volatile matter, fixed carbon et iodine indices before activation and after activation at 400˚C and 700˚C were determined which are: (6.28%; 0.97%; 73.80%; 25.23%) respectively. The best indices were found in powdered activated coal compared to grain activated coal for the concentrations used. This study can be an alternative bio-adsorbent for the urban community of Mamou in water treatment.