Imine-bonded covalent organic frameworks with abundant carboxyl groups and triazine rings for the efficient and selective removal of ciprofloxacin in actual water environments

Due to the poor treatment efficiency of wastewater with ciprofloxacin (Cip), effective removal of Cip has become a significant topic in waste management. In this study, a carboxylated COF (TzAm COF) with triazine rings is synthesized by “one-step” approach of Schiff reaction. The prepared TzAm COF possesses multiple functional binding sites, including triazine rings and carboxyl groups, enabling it achieves highly removal efficiency of ciprofloxacin in real water samples. Additionally, TzAm COF presents high Cip adsorption capacity of 217.86 mg·g −1 , good thermal and pH stability, strong resistance to ionic interference, good regenerability and excellent selectivity for Cip. Additionally, the process of monolayer adsorption and chemisorption are confirmed by the isotherms and kinetics of adsorption. The adsorption mechanisms of π-π interaction, electrostatic attraction, hydrogen bonding , channel adsorption and hydrophilic–lipophilic balance are further demonstrated by XPS , EDX , Zeta potential and FT-IR. This work aims to provide new ideas for developing novel adsorbents through the synthesis and adsorption application of carboxylated COFs. • The carboxylated COFs with triazine rings by solvent-thermal Schiff reaction. • Good thermal and p H stability, strong resistance to ionic interference and good recyclability. • High adsorption capacity (217.86 mg·g −1 ) and excellent selectivity for Cip. • High removal rates of Cip in actual water samples. • Electrostatic and π-π interaction, hydrogen bonding, channel adsorption and hydrophilic–lipophilic balance.