High-effective, convenient and environmental-friendly MOFs-chitosan-glyoxal composite film for ceftizoxime adsorption: Behavior and mechanisms.

Abstract

In this work, a novel PCN-222-chitosan-glyoxal (PCN@CSG2) composite film was constructed by loading PCN-222 in chitosan substrate, and used for ceftizoxime adsorption. The results demonstrated that the PCN@CSG not only had excellent adsorption properties for ceftizoxime, but also maintained excellent structural properties in harsh environments (strong acids and alkalis), making it have good recycling performance. Specifically, the adsorption kinetics and isotherms investigation demonstrated that the adsorption process followed the pseudo-second-order kinetic model and Freundlich isotherm model respectively, indicating that it was a multilayer process mainly controlled by chemisorption. The PCN@CSG possesses excellent absorptive capacity of 561.7 mg·g-1 and reaches equilibrium rapidly within 60 min, which is attributed to the structural advantages of PCN-222 and chitosan. The amino, carboxyl and hydroxyl functional groups of PCN-222 provide numbers of active sites and cationic chitin greatly promoted the electrostatic adsorption with negative ceftizoxime. In addition, the PCN@CSG has the advantages of renewable and environment-friendly for the biodegradation of chitosan. After five consecutive adsorption-desorption cycles, the removal rate was still higher than 90 %, confirming the excellent reusability of PCN@CSG. This work provided a great prospect for the design and application of shaped-MOFs composite materials for the removal of cephalosporins in environmental water.