Ion mobility spectrometry for evaluation of iron oxide magnetic nanoparticles ability to adsorb nalidixic acid

The contamination of water by organic pollutants, especially pharmaceutical contaminants, is one of the concerns all over the world. Among the various water pollutants, antibiotics are of particular interest to researchers because of the risk of increasing antibiotic resistance. Nalidixic acid (NA) is the first commercialized antibacterial quinolone [۱]. Ion mobility spectroscopy (IMS) is a separation method that works at atmospheric pressure. The advantages of ion mobility spectrometer are high sensitivity, low detection limit, simple operation and low cost [۲]. In the present study, ion mobility spectrometer was used to measure nalidixic acid residues in aqueous solution. The removal of nalidixic acid from water by adsorption on iron oxide magnetic (Fe۳O۴) nanoparticles has been investigated. In order to do this, Effect of NA initial concentrations (۳۰-۸۰ ppm), effects of pH (۲-۱۲), and contact time (۰.۵,۱-۵ hours) in removing of NA from aqueous solutions were investigated. Transmission electron microscope (TEM), and FT-IR were used to identify the characterization of synthesized Fe۳O۴ nanoparticles.The results indicated that ۸۷.۶ % of the NA concentration removed by Fe۳O۴ in the optimal conditions including pH=۱۲, temperature ۲۵ °C, NA concentration ۸۰ mg/L, contact time ۵ hours and adsorbent dose ۰.۵ mg/L. The resulting data from adsorption experiments had better correlation with the Freundlich isotherm and pseudo-second order kinetic model. The results of this study demonstrate that iron oxide magnetic (Fe۳O۴) nanoparticles is a suitable adsorbent for antibiotic removal from aqueous solutions.