Efficient treatment of naphthenic acids with radical/non-radical synergy–based on MoS2/Si-CQDs derived from fructose

As a typical pollutant in petrochemical wastewater, naphthenic acids are highly ecotoxic and difficult to biodegrade due to its robust structure. The advanced oxidation process has always been the research hotspot for naphthenic acids degradation and removal. In this work, with low cost and biomass fructose as raw material, Si-doped carbon quantum dots (Si-CQDs) and its composite material (MoS 2 /Si-CQDs) of Flower-like molybdenum disulfide (Flower-like MoS 2 ) were targeted synthesized by hydrothermal method, and characterized by Transmission electron microscope, Scanning electron microscope, X-Ray diffraction, UV-Vis spectroscopy, and Raman spectrum. To study the activation of prepared materials in naphthenic acid oxidative degradation, the influencing factors of kinds of materials, reaction temperature, the dosage of catalyst and persulfate were all explored systematically. The experiments showed that the naphthenic acid degradation rate of MoS 2 /Si-CQDs@NaPS system could reach more than 99 % in 120 min, and the relationship between the naphthenic acid degradation rate and the reaction temperature was in accordance with the quasi-primary kinetic equation. In mechanistic studies, the role of free radical and non-free radical pathways in oxidative degradation was verified. After five reuse cycles, the catalyst can still achieve a degradation rate of over 80 %. Finally, the experiment also tested the effectiveness of MoS 2 /Si-CQDs@NaPS system in real naphthenic acids wastewater, and the production cost of its removal of naphthenic acids was economically analyzed, showing that MoS 2 /Si-CQDs is a promising composite with stability and cost-effectiveness, and provides a new material for naphthenic acid degradation that can achieve a dual degradation pathway.