The synthesis of novel FeS2/g-C3N4 nanocomposites for the removal of tetracycline under visible-light irradiation

Abstract

Novel FeS₂/g-C₃N₄ (FC) composites were successfully constructed using an impregnation–calcination method, and they demonstrated a wonderful visible-light catalytic performance compared with unmodified g-C₃N₄ and FeS₂. The structures, morphologies, and chemical states of the samples were characterized. The photocatalytic performance was assessed based on the removal of tetracycline (TC) under visible light. The removal of TC by 20%-FC reached 83.5% within 180 min, much higher than when using g-C₃N₄ or FeS₂. The improved degradation of TC was a result of the introduction of FeS₂, which obviously enhanced the separation of photogenerated carriers at the firmly contacted interface. The effects of the key operating parameters were further explored, including the doping ratio, the concentration of photocatalyst, and the pH value. The photocatalytic theory of charge division was demonstrated using quenching experiments and electron spin resonance (ESR) studies. Finally, the FeS₂/g-C₃N₄ composite exhibited remarkable recyclability and stability. This study creates new prospects for the synthesis of photocatalysts and for the degradation of resistant organic pollutants for environmental remediation.