Magnetic Covalent Organic Frameworks for the Removal of Diclofenac Sodium from Water

Pharmaceutical contamination has drawn tremendous attention because of their adverse effects and potential risks on aquatic organisms and human health. Herein, magnetic covalent organic framework composites (MCOFs) were prepared and utilized for adsorptive removal of diclofenac sodium (DS) from water. The construction of MCOFs was achieved by integrating magnetic nanoparticles (MNPs) into a COFs’ matrix via an organic terracotta process. MCOFs featuring a highly specific area and magnetically separable ability are favorable to DS removal from water. Adsorption equilibrium can be achieved within 20 min following the pseudo-second-order kinetic model (R2 = 0.99). In addition, the experimental data achieved from adsorption isotherms demonstrated that the adsorption of DS onto MCOF-2 can be well fitted by the Freundlich adsorption model, and the maximum adsorption capacity for DS was found to be 565 mg/g. What is more important is that the high removal efficiency of DS from both actual and spiked water samples (>97.0%) was achieved by using MCOF-2 as an adsorbent. Owing to its high stability, the resultant materials exhibited excellent reusability, illustrating the great potential as sorbents for the removal of pharmaceutical contaminants.