It is well-known that chitosan consists of amino groups for the chelation of metal ions while NH 2 -MCM-41 has excellent adsorption selectivities for metals. This work compares both adsorption capacities and selectivities of chitosan and NH 2 -MCM-41. It has been found that chitosan has adsorption capacities of 1.76mmol/g, 1.03mmol/g and 1.30mmol/g for Cu 2+ , Ni 2+ and Zn 2+ respectively whereas NH 2 -MCM-41 has adsorption capacity of 1.52mmol/g, 0.8mmol/g and 0.83mmol/g for Cu 2+ , Ni 2+ and Zn 2+ . The higher adsorption capacity in chitosan is attributed to its higher loading of amine groups. The single component adsorption isotherms were well-fitted using Freundlich model. The binary adsorptions of Cu 2+ –Zn 2+ and Ni 2+ –Zn 2+ systems showed similar adsorption selectivities for both adsorbents. However, chitosan has no preferential adsorption for Ni 2+ –Zn 2+ system while NH 2 -MCM-41 has a good selectivity towards Zn 2+ . It is believed that the difference can be attributed to the heterogeneous surface of chitosan due to its organic nature. The multi-component adsorptions were best described by a multicomponent extended Freundlich model. Despite the surface functional group, this work indicates the importance of the adsorbent support on selective adsorption.