Montmorillonite impregnated electrospun cellulose acetate nanofiber sorptive membrane for ciprofloxacin removal from wastewater

Abstract The present study investigates the efficiency of electrospun montmorillonite-impregnated cellulose acetate nanofiber membranes (MMT-CA-NFM) for adsorptive removal of ciprofloxacin (CIP). Surface morphology, nanofiber characteristics and pHzpc of NFM were analysed by FE-SEM, EDS and pH drift method, respectively. The surface morphology of NFM showed random arrangements of nanofiber. Experiments were performed in batch mode to examine the effect of contact time, adsorbent dose, initial CIP concentration, pH, electrolyte, temperature and agitation speed. It was observed that 60 min contact was sufficient to reach reaction equilibrium and corresponding percentage removal was 76 % when CIP concentration, MMT-CA-NFM dose and solution pH were 10 mg/L, 4 g/L and 6.0 respectively. Equilibrium of the adsorption was described well by both Langmuir and Freundlich isotherm models. The sorption capacity was determined to be 13.8 mg/g. The sorption most closely followed Elovich kinetics model among the models tested. The pH range 6–7.5, where the zwitter ionic nature of CIP was dominant, was found to be most favourable for adsorption. Decrease of ΔG with increase in temperature demonstrated that CIP removal was favourable at higher temperature and positive values of ΔH confirmed endothermic nature of reaction. In continuous mode of operation using fixed bed column, the height of mass transfer zone was found to be 14.96 cm and adsorption rate and capacity constant in continuous mode were also calculated. The regeneration experiments indicated that 10 mM NaOH solution can desorb CIP from exhausted NFM and adsorbent demonstrated good reusability for removal of the antibiotic studied.