Photodegradation performance and transformation mechanisms of sulfamethoxazole by porous g-C3N4 modified with ammonia bicarbonate

Abstract Graphitic carbon nitride (g-C3N4) is considered to be a potential photocatalyst, while its catalytic performance is restricted by lower surface area and rapid recombination of photo-generated charge carriers. Herein, a simple method was used to prepare the porous g-C3N4 nanosheets by introducing NH4HCO3 as pore former. The as-prepared porous g-C3N4 showed a larger specific surface area, which was 56.47% larger than control. And the abundant porous structure promoted the electron transfer and inhibited the recombination of photoexcited electron and hole pairs. Furthermore, the photodegradation performance of as-prepared porous g-C3N4 was superior than control, the degradation efficiency for sulfamethoxazole (SMX) was 93.37%, which was 26.42% higher than control. Radicals like •O2− and •OH were proved to be the main active species for SMX degradation after the reactive oxygen species trapping experiments and investigation of the impacts of different pH value on the photodegradation efficiencies. The intermediates were identified by liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC–MS), and the degradation pathways of SMX were proposed. The results showed that porous g-C3N4 had an excellent performance for the degradation of SMX.