Boosting photocatalytic capability by dispersing TiO2 into chitin matrix for polystyrene microplastics degradation

Microplastics (MPs) have been demonstrated to pose significant health risks by investigations, thereby warranting an in-depth exploration of elimination techniques. In this research, TiO₂ nanoparticles were dispersed and fixed onto a chitin sponge matrix utilized the freeze–thaw method, fabricating a novel composite sponge. Analytical techniques such as XPS and SEM revealed that the TiO₂ nanoparticles were securely anchored onto the chitin network via van der Waals forces or hydrogen bonding. Notably, the distribution of TiO₂ on the chitin framework significantly influences its photocatalytic efficiency. Upon the dispersion of TiO₂, there is an observed enhancement in photocatalytic capability towards polystyrene (PS) MPs. The TiO₂/chitin composite sponge exhibited rapid and effective photocatalytic degradation efficiency, achieving 58.4 % within 6 h, and the degradation kinetics following a first-order reaction model. Furthermore, GC–MS and FTIR analyses conducted post-degradation of PS MPs uncovered the presence of three kinds of molecules containing carbonyl groups, with degradation yield of 3.26 %, 23.7 %, and 30.2 %, respectively. To summarize, this investigation introduces a approach leveraging TiO₂/chitin composite sponge as a high-performance photocatalyst, providing valuable theoretical insights for the utilization of chitin-based composite sponges in the removal of microplastics.