Structure Versus Chemical Factors in The Trapping of Fluoroquinolone Antibiotics in Clay Interlayers

Abstract

Many studies have been conducted on the adsorption of fluoroquinolone antibiotics (FQs) on Montmorillonite (MONT) and concluded that pH is the dominant factor in the interlayer adsorption of these FQs. However, little is known about how FQs of different generations adsorb onto MONT. In this study, we used both experimental and simulated data to further understand the interstratification of four different FQs, ciprofloxacin (CFX), ofloxacin (OFX), sarafloxacin (SFX) and moxifloxacin (MFX), at pH 5 and 7. The adsorption experiments show that adsorption was greater at pH 5 than pH 7. MFX showed higher affinity to MONT. X-ray diffraction analyses demonstrated that interlayer adsorption controls the extent of FQ adsorption. Molecular modeling reveals that the mechanisms of interactions that promote FQ trapping within the interlayer.