Acetaminophen removal by peroxymonosulfate catalyzed by C and O co-doped graphitic carbon nitride in synthetic secondary treatment effluent matrix

Abstract

Catalytic oxidation using carbonaceous materials and peroxymonosulfate (PMS) has attracted attention because of high potential in pharmaceuticals removal. For successful field applications, it is essential to identify the components and characteristics in real water matrices affecting the performance, though it has hardly been elaborated. Therefore, acetaminophen (ACT) removal by C and O co-doped graphitic carbon nitride (COCN) and PMS was investigated in synthetic secondary treatment effluent (SSTE) and compared to that in deionized water (DIW). ACT removal was significantly suppressed in SSTE (20.33 %) compared to that in DIW (94.20 %) under 10 mg/L ACT, 100 mg/L COCN, and 0.5 mM PMS. However, it was enhanced greatly with increasing COCN and/or PMS dose. The reactive species were the same in SSTE and DIW, of which 1O2 from O2− dominantly contributed. However, the amount of them was considerably lower in SSTE than in DIW. ACT removal was slightly affected by the anions in SSTE, such as Cl−, SO42−, and NO3−, at 1.41 × 10−3–0.71 mM. But it was suppressed greatly by 0.71 mM phosphates and by 10 mg/L humic acid and natural organic matter, via consuming hydrophobic and aromatic fractions. It is strongly suggested that the reactivity of COCN/PMS in SSTE was dominantly affected by raised pH and scavenging O2− reducing DOM, which decreased 1O2 generation. The results would significantly contribute to successful practical applications of catalytic systems.