Adsorption of naproxen and clofibric acid, two typical (pharmaceuticals and personal care products) PPCPs has been studied with virgin and modified MIL-101s, one of the typical metal-organic frameworks (MOFs). Aminomethanesulfonic acid (AMSA) and ethylenediamine (ED) were used to coordinate (using the common -NH2 group) on coordinatively unsaturated sites (CUSs) or open metal sites of the MOF to generate an acidic (-SO3H) group and basic (-NH2) group, respectively. The highest removal efficiency was observed with ED-MIL-101 both for the adsorption rate and adsorption capacity. On the contrary, the performance of the acidic AMSA-MIL-101 was very poor. Therefore, the adsorption mechanism may be explained with an acid-base interaction between the PPCPs and the adsorbents. The effect of pH on the adsorption of naproxen also supports this acid-base interaction. Moreover, a functionalized basic MOF (with -NH2) can be regenerated by simple washing with ethanol and is reusable up to at least the third run with little change in the performance along with a high adsorption capacity and rapid adsorption which is important for commercial applications. (C) 2013 Elsevier B.V. All rights reserved.