Continuous flow column adsorption and desorption for the study of interaction of fluoroquinolone antibiotic ofloxacin hydrochloride with ZnO and CuO nanometal oxides in aqueous solution

Abstract

Broad-spectrum antibiotic, major veterinary medicines, due to large consumption and inappropriate disposal contribute a major part in generation of pharmaceutical pollutants in aquatic environment. The study investigates the interaction of nanometal oxides for adsorption and desorption of Fluoroquinolone antibiotic, ofloxacin hydrochloride from aqueous solution using vertical and sequential bed adsorption columns: designing parameters of adsorption column determined using bed depth service time model. To optimize the continuous flow column adsorption, varying initial drug concentration and flow rates have been studied using ZnO and CuO nanoparticles at pH 4, already determined for optimized batch studies. To access the characteristic behaviour of breakthrough curves, Thomas model and Yoon-Nelson models have been studied, which were in good agreement with experimental data. Sequential bed column shows slightly better results than vertical bed column as the sequential bed is simple and economical, the solution flows in continuous manner under gravity without any mechanical devices and come into contact with fresh adsorbent bed having same amount as that in vertical bed. Therefore sequential bed column can consider in small scale industries for pharmaceutical wastewater treatment. Column desorption experiments have also been carried out by using HCl/NaOH as desorbing agent for the regeneration of drug loaded adsorbent column.