New approach for adsorptive removal of the antibiotic ciprofloxacin: carboxymethyl-dextran-functionalised magnetic iron oxide nanomaterials

Antibiotic residues in environmental media pose a significant health, social and economic problem and require effective removal strategies. This study presents a novel approach for the removal of the antibiotic ciprofloxacin from water sources using magnetic iron oxide nanoparticles (MNPs) synthesised by co-precipitation, and subsequently functionalised with the polysaccharide carboxymethyl-dextran (CMD). The prepared nanoadsorbent was characterised extensively by various physicochemical analyses, to evaluate its morphology, crystal structure, surface chemistry, electrokinetic properties, thermogravimetric properties and magnetic features. These analyses confirmed the successful functionalisation of the MNPs with CMD highlighting its potential for effective adsorption applications. The stability of CMD coating on MNPs was evaluated in terms of total carbon content, an important, yet often overlooked factor. The adsorption performance of MNPs@CMD for ciprofloxacin was investigated systematically by studying the effects of adsorbent dosage, pH, initial ciprofloxacin concentration, ionic strength, adsorption time and kinetics, temperature, and reusability. Under optimal conditions, nanoadsorbent exhibited a satisfactory maximum adsorption capacity of 14.71 mg/g, and maintained a removal efficiency of 79 % after four cycles, with minimal desorption of CMD layer on the MNPs. These findings demonstrate the potential of this magnetic polysaccharide nanoadsorbent for effective removal of ciprofloxacin from aqueous environments, enabling magnetic recovery and reuse.