Magnetite/ceria-based composites for effective adsorption of pharmaceuticals and pesticides in water

Contamination of water sources by pharmaceuticals and agricultural pollutants has become an urgent environmental issue. A magnetic cerium oxide composite (FeCe oxides) was synthesized and used as an effective adsorbent for the removal of 2,4-dichlorophenoxyacetic acid (2,4-D) and cephalexin (CEF) from aqueous solution. The magnetic core of FeCe composite was prepared from commercial chemicals (common food additives or flocculants) or the commercial pigment was used directly as a magnetic core without further purification. The adsorption kinetics and mechanism governing the removal of CEF and 2,4-D by FeCe composites were studied in detail. The measured data were fitted by the commonly used isotherms (Langmuir, Langmuir-Freundlich, Freundlich and Temkin). The results showed that the adsorption of 2,4-D and CEF followed Freundlich and Langmuir-Freundlich isotherm with the maximum adsorption capacity of 55.7 mg/g (2,4-D) and 110.7 mg/g (CEF), respectively. Also, 2,4-D and CEF adsorption on the composite follow pseudo-second-order kinetics. The study showed that the FeCe composites have high efficacy in eliminating 2,4-D and CEF from aqueous solution with the added benefit of simple separation of the used composites. Therefore, they can be considered as promising and effective tools for water purification.