Effective degradation of tetracycline via recyclable cellulose nanofibrils/polyvinyl alcohol/Fe3O4 hybrid hydrogel as a photo-Fenton catalyst

In this work, the method of in-situ co-precipitation was used to prepare PVA/CNF/Fe3O4 hybrid hydrogel, and the relationship between its structure and performance was explored. The Fe3O4NPs prepared by this method were dispersed on the carrier PVA/CNF hydrogel and were easy to recover. The catalytic degradation of tetracycline was investigated using PVA/CNF/Fe3O4 hybrid hydrogel as photo-Fenton catalysts. The results showed that light and hydrogel carriers were pivotal factors in promoting Fe2+ and Fe3+ cycling and that the PVA/CNF/Fe3O4 hybrid hydrogel as catalysts were able to activate H2O2 to generate a large amount of oxygen radical •OH, resulting in efficient removal of tetracycline. The tetracycline degradation followed a proposed first-order kinetic model and achieved a removal rate of about 98% in 120 min at an optimum pH of 3, H2O2 100 mM, catalyst 0.3 g/L, and a temperature of 25 °C.