An investigation was conducted on the introduction of amino groups to the surface of activated carbon and the adsorption characteristics of the aminated surface. The organic chemical reactions allowed us to introduce amino groups to the surface of activated carbon without affecting the physical structure of the adsorbent. The introduction of amino groups lowered the adsorbancy of activated carbon in the adsorption of benzoic acid from solution, while it produced a remarkably favorable effect in the adsorption of NO in the gas phase.