Exploring charge transfer and degradation mechanism of one-step synthesized modified g-C3N4 for efficient photocatalytic bisphenol A removal under visible light

This study introduces a novel one-step, template-assisted synthesis of modified graphitic carbon nitride (MCN) using calcium cyanamide (CaCN2) as a template via calcination, and investigates its performance in the photo-catalytic degradation of bisphenol A (BPA) under visible-LED irradiation. The characterization results confirmed the successful modification of MCN using CaCN2 as a template, which was subsequently removed through washing with diluted HCl. The optimized sample, MCN-0.25, demonstrated significantly enhanced degradation efficiency, exhibiting notably high reaction kinetics and achieving complete removal of BPA within 40 min. It demonstrated 3.6 times higher degradation performance compared to the parent bulk carbon nitride (BCN) after 40 min of reaction time under visible-light irradiation. The corresponding reaction kinetic rate was 0.089 min(-1). The enhanced photocatalytic performance is primarily attributed to the increased photocurrent generation and reduced charge-carrier recombination rate. Furthermore, electron paramagnetic resonance analysis identified DMPO-trapped superoxide radicals (center dot O-2(-)) as the dominant reactive oxygen species, confirming their crucial role in the degradation process. The toxicological predictions reveal that BPA has moderate toxicity and most degradation intermediates are less toxic. Our development of MCN catalysts demonstrates a superior photo-catalytic degradation performance compared to previous reports, achieved through the use of cost-effective materials and a novel one-step synthesis method, thereby enhancing organic pollutant removal. These improvements underscore the effectiveness of our approach in addressing pollutant degradation challenges and its potential application in water treatment.