Double-lanthanide functionalized covalent organic framework hybrid material for the enhanced adsorption of fluoroquinolone antibiotics via synergistic effect

Developing high-efficiency sorbents for the removal of fluoroquinolone (FQ) contaminants is of great significance for water environmental conservation. In this study, double lanthanide ions were loaded onto a specially designed SO 3 H-decorated covalent organic framework (TpPa-SO 3 H) to obtain hybrid sorbent material (Tb-Eu@TpPa-SO 3 H) for the removal of typical FQs present in wastewater. Tb-Eu@TpPa-SO 3 H was a porous nanostructure of high density with evenly distributed Tb, Eu and sulfonic acid as active groups. Sulfonic acid groups could bind amine sites of FQs molecules through electrostatic interaction. Double lanthanide ions binded FQs according to dinuclear charge transfer complex with β-diketones unit in FQs molecule. Tb-Eu@TpPa-SO 3 H with multiple active sites exhibited a synergistic effect for FQs adsorption from water. Tb-Eu@TpPa-SO 3 H revealed unprecedentedly high adsorption capacity of 1111, 1147, and 1176 mg/g for norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENR), respectively, accompanied by fast removal rates (99 % adsorption efficiency within 2 min). Further, the results of analysis on contaminated seawater suggested enormous potential of the developed material Tb-Eu@TpPa-SO 3 H in practical applications. These findings promoted the development of the designs and preparations of lanthanide functionalized covalent organic framework hybrid materials and their application to the removal of organic contaminants.