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 nano-flower (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 & mu;M, [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 & mu;M) and showed a 24.0 % increase in H2O2 activation efficiency, reaching 50.0 %. The electron para-magnetic resonance (EPR) determinations and active species trapping experimental data revealed that & BULL;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.