Microwave-Assisted Rapid Synthesis of Novel Nitrogen-Rich Covalent Organic Frameworks for Ibuprofen Removal from Aqueous Solution

Abstract

Covalent organic frameworks (COFs) are an ideal adsorbent because of its high chemical stability, predictable structure and adjustable pore size for ibuprofen (IBP) which is difficult to adsorb. However, conventional synthesis methods for COFs usually require long reaction time. In this study, we successfully synthesized a novel COF material Schiff base network-1 (SNW-1) by microwave-assisted method for absorbing (IBP), which effectively reduced the reaction time to only 0.5 h compared with the solvothermal method (72 h). The results showed that SNW-1revealed an excellent absorption capacity for IBP at room temperature. The results showed that the adsorption of SNW-1 was consistent with Freundlich model (R² = 0.9999) and pseudo-second order kinetic model (R² = 0.9984). The underlying adsorption mechanism was due to π‒π interactions, hydrogen bonding interactions, and electrostatic attractions. The presence of abundant nitrogen elements in SNW-1 promoted the formation of hydrogen bonds, thereby enhancing the adsorption process. In addition, SNW-1 could be easily regenerated using ethanol and also had a good adsorption effect on ibuprofen after 5 cycles. This study provided an economical and rapid preparation method for the treatment of solutions containing ibuprofen.