Though adsorption is a promising method to treat anitibotics pollution, the complexity of many kinds of antibiotics molecules and the multiple roles of organic functional groups in organo-functionalized mesoporous silicas adsorbents cause diverse interactions between the antibiotics and the adsorbents. Here, we prepared SBA-15, SH-SBA-15 and SO3H-SBA-15 with comparable textural and structural property for the adsorption of ciprofloxain to elucidate the dual roles of organic functional groups. It is found that the beneficial electrostatic interaction of SO3H-SBA-15 precedes its disadvantageous hydrophilicity for adsorption, which is different from amine functionalized mesoporous materials as reported elsewhere. The potential antibiotics adsorbents, SO3H-SBA-15, could be reused 3 times without obvious decrease of adsorption property. (C) 2015 Elsevier B.V. All rights reserved.