Cellulose nanocrystals mediated spontaneous weaving of ZIF-67 hybrid networks: Enhanced peroxymonosulfate activation and rapid removal of dye

Abstract

Inter-connected zeolite imidazolate framework-67 (ZIF-67) hybrid networks were successfully synthesized by a cellulose nanocrystals (CNCs) mediated spontaneous weaving strategy, which was denoted as ZIF-67@CNC, and was applied to activate peroxymonosulfate (PMS) for Rhodamine B (RhB) degradation. Characterizations results demonstrated that the ZIF-67 nanocrystals are encapsulated within CNCs and subsequently arranged in a string-like configuration. In comparison to pristine ZIF-67, the ZIF-67@CNC catalyst presented superior performances for RhB dye removal both in terms of degradation efficiency and rate, as the kinetic rate constant increased 5.8-fold. This finding was attributed to the improvement in oxygen-containing groups and meso/microporous structures after the introduction of CNCs, leading to efficient binding to compounds and rapid molecular diffusion. Moreover, the ZIF-67@CNC exhibited remarkable stability throughout the catalysis process in aqueous solutions owing to the robust crosslinking between negatively charged CNCs and positively charged cobalt ions, which significantly mitigated the potential secondary pollution of cobalt to the environment. This research opens up new possibilities for the design of highly efficient and durable ZIF-67-based catalysts to promote future wastewater treatment technology.