Porous visible light-responsive Fe3+-doped carbon nitride for efficient degradation of sulfadiazine.

The development of efficient solar driven catalyst for the degradation of antibiotics has become increasingly important in environmental protection. However, the reported efficient photocatalysts for antibiotic degradation are limited. In this work, porous Fe3+-doped graphitic carbon nitride (g-C3N4) with outstanding photocatalytic ability is synthesized and then used as the photocatalyst for the efficient degradation of sulfadiazine (SDZ) under visible light. A series of characterization results indicate that Fe3+ is successfully doped into the interlayer of g-C3N4 and is stabilized in g-C3N4 by Fe-N coordination bond. The SEM, DRS and ESI and transient photocurrent results demonstrated that Fe3+-doped g-C3N4 has a porous structure, a low band gap, improved separation efficiency of photogenerated electron and holes as well as a wider light absorption range. Such improved physical and chemical properties greatly enhanced the photocatalytic ability. Using Fe3+-doped g-C3N4 for photocatalytic degradation of SDZ under white light, almost complete degradation of SDZ was achieved with a degradation efficiency as high as 99.8% (whereas only 52.1% for bulk g-C3N4) within 90 min. The degradation was mainly ascribe to 1O2 during the irradiation, and also a small amount of •O2-, OH• and h+ are involved in the degradation process. The Fe3+-doped g-C3N4 was applicable for the degradation of a wide range of antibiotic pollutants.