Laboratory Investigation of Antibiotic Interactions with Fe2O3 Nanoparticles in Water

The movement and degradation of drugs in soil and water environments are related to surface interactions with oxide nanoparticles. These nanoparticles could be stationary substrates or suspended in aqueous solution. In this study, different pH solutions of the common antibiotic ampicillin (AMP) were mixed with 50-nmFe2O3 (maghemite) particles. Both sorption and breakdown of AMP were observed. For initial drug concentrations from approximate to 3M to 2.9mM, the overall AMP removal from solution can be described by linear isotherms with removal coefficients (Kr) of 394 (+/- 43) Lkg-1 at pH 2, 551 (+/- 37) Lkg-1 at pH 6, and 256 (+/- 37) Lkg-1 at pH 8. At pH 4, AMP removal can be described by a Freundlich isotherm of logKf=3.27 (+/- 0.19) and n=0.57 (+/- 0.15). AMP solutions were separated from maghemite nanoparticles after mixing and analyzed by liquid chromatography/mass spectroscopy (LC/MS) techniques, resulting in the detection of penicilloic and penilloic acid breakdown products. (C) 2016 American Society of Civil Engineers.