Sustainable and energy-efficient degradation of acetaminophen in water using an optimized Fenton-like system with iron-doped graphitic carbon nitride catalyst

Pharmaceutical contaminants such as acetaminophen (APAP) present significant environmental and public health risks in aqueous environment. This study focuses on the degradation of APAP using iron-doped graphitic carbon nitride (Fe-g-C 3 N 4 ) catalysts in a Fenton-like system. The Fe-g-C 3 N 4 catalyst with highly dispersed iron enabled efficient hydrogen peroxide (H 2 O 2 ) activation, achieving near-complete APAP degradation within 30 min across a wide pH range. Key factors including iron content of Fe-g-C 3 N 4 catalyst, H 2 O 2 concentration, catalyst dosage and pH value were optimized to enhance efficiency and stability, while minimizing iron leaching. The Fe-g-C 3 N 4 /H 2 O 2 system demonstrated low energy consumption, quantified as electrical energy per log order (EE/O), underscoring its cost-effectiveness. The oxidizing properties of Fe-g-C 3 N 4 /H 2 O 2 system was little affected by the inorganic anions and organic matter commonly found in the aqueous environment. The APAP degradation process in Fe-g-C 3 N 4 /H 2 O 2 system involved radical (•OH and O 2 •- ) and non-radical ( 1 O 2 ) pathway. The APAP degradation intermediates were detected to propose degradation pathways and assess toxicity. This work offers a sustainable and energy-efficient solution for the removal of pharmaceutical micro-pollutants, with promising applications for large-scale water treatment.