Regenerable g-CN-chitosan beads with enhanced photocatalytic activity and stability.

In this study, a series of regenerable graphitic carbon nitride-chitosan (g-CN-CS) beads were successfully synthesized the blend crosslinking method. The prepared beads were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The structural characterization results indicate that the g-CN granules were uniformly distributed on the surface of the chitosan matrix, and the structures of g-CN and CS are maintained. In addition, the prepared g-CN-CS beads exhibited efficient MB degradation and stability. The optimum photocatalytic activity of our synthesized g-CN-CS beads was higher than that of the bulk g-CN by a factor of 1.78 for MB. The improved photocatalytic activity was predominantly attributed to the synergistic effect between adsorption and photocatalytic degradation. In addition, the reacted g-CN-CS beads can be regenerated by merely adding sodium hydroxide and hydrogen peroxide. Additionally, the regenerated g-CN-CS beads exhibit excellent stability after four runs, while the mass loss is less than 10%. This work might provide guidance for the design and fabrication of easily regenerated g-CN-based photocatalysts for environmental purification.