Mechanisms of ciprofloxacin removal by nano-sized magnetite

► Ciprofloxacin adsorbs strongly onto nano-magnetite. ► Adsorption is dependent on pH with the higher adsorption observed at pH 5.5-6. ► Ionic strength has negligible effect on adsorption isotherm at low surface coverage. ► IR data indicated inner-sphere nature of the adsorption. ► IR data suggested that ciprofloxacin formed a bridging bidentate surface complex.