In this study, removal of some heavy metals ions $(Mn^{2+}, Fe^{2+}, Ni^{2+} and Cu^{2+})$ from aqueous solution by adsorption was investigated. For this purpose, high-grade MnSO4.H2O, FeSO4.7H2O, NiSO4.7H2O and CuSO4.5H2O were used as heavy metal samples. The commercial activated carbon (Merck 2514), chitosan and agar were used as adsorbents. The pH of each solution was not controlled. This is because the net interaction between the adsorbent and the heavy metal could be disturbed by the buffer solution. Therefore, all experiments were carried out in a pH range from 5.3 to 5.5. The equilibrium adsorption contact times were determined for M - 2514. The adsorption rate constants were determined from obtained kinetics curves suitable for first degree of rate kinetics. Adsorption isotherms of heavy metals on M - 2514 from aqueous solution were determined. These adsorption isotherms were seen to be consistent with Freundlich's adsorption isotherm. k and n constants were determined from Freundlich's linear equation. In addition, M - 2514, chitosan and agar were compared according to their percent uptake yields of the heavy metals.