Degradation studies of ciprofloxacin on a pillared iron catalyst

Photo-assisted Fenton mineralization of ciprofloxacin (CFX), a broad-spectrum antibiotic used in human and veterinary medicine was studied using a modified laponite clay-based Fe nanocomposite (Fe-Lap-RD) as a heterogeneous catalyst in the presence of hydrogen peroxide and UV light. The catalytic performance has been monitored in terms of CFX (0.15 mM) and total organic carbon (TOC) conversions, whereas the catalyst stability was evaluated according to the metal leached from the solid structure into the aqueous solution. The Fe-Lap-RD was characterized by Xray photoelectron spectroscopy (XPS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) techniques. Further, the effects of reaction parameters such as H2O2 concentration, Fe-Lap-RD catalyst loading and initial solution pH on the mineralization of CFX were investigated. It was found that at the optimal reaction conditions (60 mM H2O2, 1.0 g L-1 Fe-Lap-RD, initial solution pH 3.0), complete CFX degradation and over 57% total organic carbon (TOC) removal of CFX can be achieved after 30 min reaction. In addition degradation and mineralization kinetics of CFX was also studied to obtain apparent reaction rate constants. The photo-Fenton degradation of CFX follows the pseudo-first-order kinetics. Fe-Lap-RD exhibits good catalytic activity in the photodegradation and mineralization of CFX, with negligible leaching of Fe ions from the catalyst structure. (C) 2008 Elsevier B.V. All rights reserved.