| Naphthenic acids（NAs）is a toxic component in refinery wastewater.In recent years,with the development of petrochemical industry,a large amount of NAs in petrochemical industry wastewater has accumulated in the environment,causing serious environmental pollution.In this paper,for the development of convenient detection and degradation techniques for NAs,a series of carbon quantum dots（CQDs）and their composites were designed and synthesized.The applications of CQDs and their composites in the fluorescence trace detection of NAs and advanced oxidative degradation of NAs by persulfate were investigated.1)Fluorescence trace detection of NAs based on PEG-CQDsA fluorescent CQDs（PEG-CQDs）with near-infrared emission was designed and synthesized by one-step solvothermal method using polyethylene glycol 400（PEG400）and p-phenylenediamine（PPD）as precursors,as a fluorescent probe for the trace detection of NAs.A series of characterization methods were used to investigate the physical and chemical properties of PEG-CQDs,and a quantitative detection system for NAs based on PEG-CQDs was successfully constructed.In addition,the mechanism of the detection of NAs by PEG-CQDs was also speculated,and PEG-CQDs was successfully applied to the detection of NAs in real industrial wastewater.2)Oxidative degradation of NAs based on Si-CQDs by persulfateA silicon-doped CQDs（Si-CQDs）was designed and synthesized by one-step solvothermal method using lauryl betaine and D-fructose as precursors and tetraethyl silicate as silicon source.Si-CQDs was used as catalyst in advanced oxidation system to study the feasibility of its application in oxidative degradation of NAs by activated sodium persulfate（Na PS）.By optimizing the oxidation reaction conditions（reaction temperature,catalyst dosage,oxidant dosage,etc.）,the oxidation degradation rate of NAs reached 93.17%in Si-CQDs@Na PS system within 120 min.The active substances in Si-CQDs@Na PS system were studied by Electron Paramagnetic Resonance（EPR）technique,and the cause of NAs degradation was speculated.3)Oxidative degradation of NAs based on Mo S2/Si-CQDs by persulfateA molybdenum disulfide flower-like microsphere（Mo S2）was prepared.The Mo S2/Si-CQDs composite was obtained by hydrothermal composite of Mo S2 and Si-CQDs.The oxidative degradation of NAs in Mo S2/Si-CQDs@Na PS system was investigated using Mo S2/Si-CQDs as catalyst and sodium persulfate as oxidant.Compared with the Si-CQDs@Na PS system,Mo S2/Si-CQDs@Na PS system showed a great improvement in the oxidative degradation of NAs.By optimizing the oxidation reaction conditions,the oxidation degradation rate of NAs reached 99.42%in Mo S2/Si-CQDs@Na PS system within 120 min.Based on the results of EPR test on the possible active components in Mo S2/Si-CQDs@Na PS system,the mechanism of NAs degradation was speculated. |
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