Fenton-like degradation of tetracycline on MgO/P-doped g-C3N4 with low H2O2 consumption: behavior and mechanism

Fenton-like oxidation is a widely used advanced oxidation processes (AOPs) for the removal of persistent organic compounds. However, its development is significantly constrained by low H 2 O 2 utilization, the loss of transition metal ions, and the presence of harsh acidic conditions. Herein, a catalyst composed of MgO supported on porous P-doped graphitic C 3 N 4 (P-CN) was fabricated using a straightforward stepwise calcination process. The catalyst exhibited excellent performance in catalyzing the degradation of tetracycline (TC) through activated H 2 O 2 in the dark. The maximum reaction rate constant of the synthesized catalyst for TC degradation was 0.034 min −1 , which was nearly 62 times that of MgO and 18 times that of CN. The enhancement of catalytic properties was attributed to the doping of g-C 3 N 4 by P and the N-Mg bonds formed between g-C 3 N 4 and MgO, which not only enhanced charge transfer capabilities but also promoted the conversion of H 2 O 2 into 1 O 2 , •OH, and •O 2 − , thereby benefiting the degradation of pollutants. The effects of various parameters, including catalyst dosage, pH level, common interfering substances, and H 2 O 2 and TC concentrations, on degradation efficiency were examined in detail, and the ecological risk associated with the catalytic degradation of TC was predicted. In addition, the MgO/P-CN catalyst exhibited high stability, low H 2 O 2 consumption, and a broad pH range, had no transition metal components, and did not require an external energy input, demonstrating potential for the removal of organic pollutants and toxic waste.