Magnetic 2D/2D oxygen doped g-C3N4/biochar composite to activate peroxymonosulfate for degradation of emerging organic pollutants

Herein, magnetic 2D/2D oxygen-doped graphite carbon nitride/ biochar (gamma-Fe2O3/O-g-C3N4/BC) composite was rationally fabricated and used to activate peroxymonosulfate (PMS) for the degradation of emerging organic pollutants. O-g-C3N4 or coconut-derived biochar (BC) displayed low catalytic activity to PMS, while gamma-Fe2O3/O-g-C3N4/BC composite showed superior catalytic activity, in which complete degradation of antibiotic sulfamethoxazole (SMX) was quickly achieved, with the mineralization ratio of 62.3%. The surface-bound reactive species (dominant) and sulfate radicals as well as hydroxyl radicals contributed to SMX degradation. Visible light could accelerate SMX degradation and enhance SMX mineralization, suggesting that gamma-Fe2O3/O-g-C3N4/BC composite had good photocatalytic activity. The superior catalytic activity of gamma-Fe2O3/O-g-C3N4/BC composite to activate PMS and visible light was attributed to the enhanced interfacial charge transfer and adsorption capacity. In addition to antibiotic SMX, other typical emerging organic pollutants, including atrazine, phenol, nitrobenzene and carbamazepine could also be degraded and mineralized in the system of visible light/O-g-C3N4/BC/PMS, indicating its wide applicability for degradation of various toxic organic pollutants in water and wastewater.