Adsorption study on the removal of ciprofloxacin in aqueous solution by an acidic ion exchange resin with bifunctional group

Abstract

Removal of fluoroquinolone antibiotic pollutants in the aquatic environment has become a research hotspot. In this work, two skeletal resins and four acidic ion exchange resins have been used as adsorbent materials to evaluate their adsorption properties for fluoroquinolone antibiotic ciprofloxacin (CIP) in aqueous solution. Compared with other materials, the sulfonic-phosphoric acid-based bifunctional resin S9570 has shown the best adsorption performance for CIP. The effect of solution pH on the adsorption of CIP by S9570 has been further explored, and the optimal adsorption capacity has been obtained at pH 4.0. The adsorption kinetics and thermodynamics of S9570 for CIP have been investigated in details. The high fits of the pseudo-second-order and intraparticle diffusion equations indicate that these two models can better describe the adsorption process of S9570 for CIP which has been jointly controlled by chemical adsorption and intraparticle diffusion steps and has been accompanied by weak or intermediate initial adsorption behaviour. The best fit results of Langmuir has indicated that there exists a monolayer adsorption on the surface of the S9570.Thermodynamic parameters suggest that the adsorption is an endothermic, spontaneous process with increased randomness at the solid-liquid interface. Through this evaluation of resin adsorption materials, it has been proved that the adsorbent material has good reusability and antiinterference performance.