Promotion of ciprofloxacin adsorption from contaminated solutions by oxalate modified nanoscale zerovalent iron particles

Falyouna, O.*; Idham, M. F.*; Maamoun, I.; Bensaida, K.*; Ashik, U. P. M.*; Sugihara, Yuji*; Eljamal, O.*

Water contamination by ciprofloxacin (CIP) is a global and emerging issue because it increases the risk of infection by antimicrobial resistant bacteria. CIP removal from water by iron nanoparticles (Fe) with the presence of oxalate hasn't been reported yet. The present study demonstrated that the addition of oxalate to Fe nanoparticles improved the removal of CIP under the following optimum conditions: dose = 0.3 g L, oxalate = 0.3 mM, initial pH = 7, and temperature = 25 C. Furthermore, the experimental results illustrated that high concentrations of dissolved oxygen in the aqueous solution greatly decreased the removal efficiency of CIP by Fe oxalate system. In addition, the desorption experiments and the results of SEM-EDS, XRD, and FTIR revealed that physisorption and chemisorption were responsible for CIP removal by Fe oxalate system as the addition of 0.3 mM of oxalate boosted the surface complexation between Fe nanoparticles and the carboxylic, ketone, and piperazinyl groups in CIP. These results were supported by the outcomes of kinetics, isotherm, and thermodynamic analysis. Finally, this study proved that Fe oxalate system is inexpensive, practical, and more efficient than most of the reported Fe-based systems with a maximum adsorption capacity of 294.66 mg g.