A novel biodegradable porous graphitic carbon nitride/poly(lactic acid) fiber photocatalyst for efficient elimination of carbamazepine under solar irradiation

Developing efficient photocatalytic materials for the elimination of emerging contaminants is of great significance for wastewater treatment. However, photocatalysts in powder form usually suffer from the problems of easy agglomeration and difficult recycle in water. Herein, graphitic carbon nitride/polylactic acid (g-C3N4/PLA) fiber composites with highly hierarchical macro/mesoporous structure were constructed by a simple and efficient methods of centrifugal-electrostatic spinning and alkali treatment. The porous structure of fiber could provide abundant space to immobilize g-C3N4 nanosheets, avoiding the wrapping of g-C3N4 inside the fiber and creating more active sites for photocatalytic reaction. Importantly, the carbamazepine (CBZ) removal rate by porous g-C3N4/PLA fiber composites under solar irradiation was as high as 99% in 2 h. The reaction mechanisms and CBZ degradation pathways were identified. Superoxide radical (•O2−), singlet oxygen (1O2) and hole (h+) were regarded as dominant active species in porous g-C3N4/PLA photocatalytic system for photocatalytic degradation of CBZ. The porous fiber composites not only possessed superior photocatalytic activity, repeatability and stability, but also could be biodegraded in natural environment without secondary pollution. This work proposed a promising way for developing efficient, stable and environmental-friendly photocatalytic materials for the removal of CBZ and other emerging contaminants in wastewater.