High-efficient degradation of chloroquine phosphate by oxygen doping MoS₂ co-catalytic Fenton reaction

To degrade the antiviral and antimalarial drug chloroquine phosphate (CQP), an oxygen doping MoS₂ nanoflower (O-MoS₂-230) co-catalyst was prepared by a hydrothermal method to construct an O-MoS₂-230 co-catalytic Fenton system (O-MoS₂-230/Fenton) without pH adjustment (initial pH 5.4). Remarkable CQP degradation efficiency (99.5 %) could be achieved in 10 min under suitable conditions ([co-catalyst] = 0.2 g L^-1, [Fe²⁺]₀ = 70 μM, [H₂O₂]₀ = 0.4 mM) with a reaction rate constant of 0.24 min^-1, which was 4.8 times that of MoS₂ co-catalytic Fenton system (MoS₂/Fenton). Compared to MoS₂/Fenton, the system had 1.5 times more Fe²⁺ (28.4 μM) and showed a 24.0 % increase in H₂O₂ activation efficiency, reaching 50.0 %. The electron paramagnetic resonance (EPR) determinations and active species trapping experimental data revealed that •OH and ¹O₂ were responsible for CQP degradation. The combination of experiments and density functional theory (DFT) calculation demonstrates that O doping in MoS₂ modifies the surface charge distribution, leading to an increase in its conductivity, thus accelerating the Fe³⁺/Fe²⁺ cycle and promoting reactive oxygen species (ROS) generation. Furthermore, O-MoS₂-230/Fenton system exhibited excellent stability. This work reveals the degradation mechanism of accelerated Fe³⁺/Fe²⁺ cycle and abundant ROS in the O-MoS₂-230/Fenton system and provides a promising technology for antibiotic pollutant degradation.