Fotodegradação de contaminantes emergentes por catalisadores à base de PHI (Poli Heptazina Imida)

Abstract

The remediation of pollutants promoted by systems that are cheap and viable remains an important challenge in the field of catalysis. Carbon nitrides applied in photocatalytic systems are a promising class of materials for promoting advanced oxidative processes, with several studies demonstrating their potential in removing contaminants. In the work that follows, rifampicin and tetracycline, two antibiotics with latent human and environmental toxicity, were photodegraded/removed by Fe-PHI, a crystalline carbon nitride with potential applications in oxidative reactions. The synthesis of the material followed the processes reported in the literature. Unlike other orders of the class, the PHI has cations inserted between the heptazine structures, which can be exchanged for other transition metals, being classified in certain cases as single-atoms, catalytic sites with good activity and stability. The obtained catalysts had their structure analyzed by DRX, FT-IR, HR-TEM and EXAFS. Contaminants were reserved in aqueous solution and their respective photodegradations/adsorptions were monitored by spectroscopy in the UV-Vis region (~80% removal), being almost 100% remedied in the subsequent irradiation. Tetracycline, once more durable in the medium, displayed around 65% of remediation in 8 hours of irradiation with Fe-PHI and neutral pH. The catalyst recycles showed continuous activity, for both sorption and photoremediation. With such a prolonged activity, in addition to its simple synthesis, carbon nitrides have shown promise in the application of contaminant removal.