The synergistic effect of Fe3O4/g-C3N4 for persulfate activation in sulfate radical photo-Fenton

The Fe3O4/g-C3N4 composite has been successfully synthesized using coprecipitation method. The light absorption capabilities of g-C3N4 and Fe3O4 demonstrate synergistic effect in activating persulfate (PS). This synergistic effect occurs at Fe3O4 loading of 22-35 mass%, which has the effectiveness of hole-electron separation. The Fe-N coordination bonds were present, reflecting the interfacial chemical interactions between g-C3N4 and Fe3O4. The PS-activated Fe3O4/g-C3N4 system can completely degrade methyl orange (MO) in 15 min under visible light illumination (lambda > 420 nm). Radical scavenging experiments show that SO4 center dot-, (OH)-O-center dot, O-center dot(2)-, and h(+) play a role in the degradation of organic pollutants. Other organic pollutants, such as methylene blue, rhodamine B, crystal violet, and phenol were also successfully degraded, indicating that this system has strong non-selective oxidative capabilities. Therefore, the Fe3O4/g-C3N4/PS system has high photocatalytic activity, high magnetic properties and stability, and potential for application in the water treatment of organic pollutants.