CoAl2O4/Co3O4/boron and nitrogen doped biochar for round-the-clock ultra-efficient degradation of 4-nitrophenol with peroxymonosulfate.

Abstract

Developing a new strategy to boost the degradation efficiency of photocatalysts for toxic phenolic compounds in peroxymonosulfate (PMS)-based degradation processes was essential but remained an challenging task. Our study proposed the one-pot construction of CoAl₂O₄/Co₃O₄/boron and nitrogen doped biochar (CoAl₂O₄/Co₃O₄/BNC) to accelerate the PMS activation and enable ultra-fast degradation of 80 mg L^-1 nitrophenol (4-NiP). Radical species (˙OH, SO₄˙^-, and h⁺) and non-radical (¹O₂) played crucial roles during the degradation process. Additionally, 4-NiP was effectively degraded across the full pH range. The catalyst's stability in simulated real aqueous environments was evaluated, demonstrating that the CoAl₂O₄/Co₃O₄/BNC exhibited excellent recyclability and anti-interference capability during degradation. Under UV-visible light irradiation, 80 mg L^-1 of 4-NiP was degraded within 10 min, it has been demonstrated that illumination accelerates the activation of PMS and the photocatalytic degradation rate of 4-NiP. Furthermore, the degradation efficiency exceeded 95% for seven types of organic pollutants in different water matrices. Seven types of organic pollutants included levofloxacin (LEV), tetracycline (TC), doxycycline hydrochloride (DOX), ciprofloxacin (CIP), 2-chloro-4-nitrophenol (2C4Nip), 2-chloro-6-nitrophenol (2C6Nip), these results confirmed the capability of CoAl₂O₄/Co₃O₄/BNC to activate PMS for degrading organic pollutants in wastewater.