Graphite carbon nitride coupled with high-dispersed iron (II) phthalocyanine for efficient oxytetracycline degradation under photo-Fenton process: Performance and mechanism

Abstract

Antibiotic contamination has become an environmental problem that cannot be ignored, and there is an endless demand for high performance advanced oxidation technologies to efficiently remove antibiotics from wastewater. Iron (II) phthalocyanine (FePc) with monoatomic dispersed iron sites has great potential for Fenton-like catalysis, but its tendency to aggregate in aqueous environments leads to self-degradation, poor electrical conductivity, and masking of active centers, which severely limits its practice application. Herein, aiming at these disadvantages, a novel FePc/g-C3N4(CNFP)/H2O2 photo-Fenton system was constructed. In CNFP, the highly dispersed FePc on g-C3N4 not only avoided the self-degradation caused by high aggregation, but also provided more active centers. Additionally, the π-π interaction between FePc and g-C3N4 formed a quick-speed electron transfer routeway, which enabled the fast transfer of photogenerated electrons. g-C3N4 as a photocatalytic center can continuously provide photogenerated electrons for FePc to realize the rapid regeneration of Fe(II). In CNFP/H2O2 photo-Fenton system, the coexistence of radicals and non-radicals (OH, O2−, h+, and 1O2) enhanced the anti-interference ability. The self-degradation analysis showed that FePc had obvious self-degradation in the photo-Fenton process, while CNFP had no self-degradation. Furthermore, the CNFP/H2O2 photo-Fenton system was carefully evaluated by pH effect, ions effect, toxicity assessment, and cycling experiments, revealing its application potential in practical wastewater treatment.