Five modified nano materials from chitosan have been prepared and characterized. These materials comprise cross-linked aminated, sulfated, carboxylated and sulfated-carboxylated chitosan. They were applied for both the adsorption of some heavy metal and for some cationic, anionic, and anionic azodyes. The extent of adsorption depends on the selectivity between the modified materials and the desired metal ion. Ag(I) is the most preferable metal ion by all modified materials whereas Cu(II) is preferable by carboxylated- sulfated chitosan. For dye adsorption, the maximum adsorption capacity depended strongly on the modified material. The crosslinked and aminated materials are more selective for anionic dyes whereas the sulfated, carboxylated and carboxylated-sulfated materials are more selective for cationic dyes.