Magnetic ion exchange resin for effective removal of perfluorooctanoate from water: study of a response surface methodology and adsorption performances

This research exhibited the use of magnetic ion exchange (MIEX) resin as an effective adsorbent for the removal of perfluorooctanoate (PFOA) in aqueous solution. The adsorption performance of PFOA was investigated by a batch experiment. All kinds of factors affecting the adsorption of PFOA, including adsorbent dosage, initial concentration, adsorption time, temperature, stirring intensity, coexistent anions, initial solution pH, natural organic matter, ion strength, and bed volume were studied. Moreover, the response surface methodology was put into use to know the key parameters affecting PFOA removal efficiency. The sorption equilibrium and kinetic data could conform well to the Langmuir and pseudo-second-order model, respectively. Thermodynamic parameters were obtained, and it was observed that the adsorption of PFOA onto MIEX resin was an endothermic and spontaneous process at the temperatures under investigation. It was summarized that both chemical absorption and physical adsorption were involved in the PFOA sorption onto the MIEX resin. Moreover, the MIEX resin could be effectively regenerated using a saturated sodium chloride solution. A series of batch experiments and characterizations demonstrated that the MIEX resin possessed a strong adsorption ability with the removal efficiency exceeding 90%, allowing a possible practical application in future water treatment.