Research On The Degradation Of Quinolone Antibiotics In Water By Sea Urchin-like W₁₈O₄₉ Based Nanocomposites

Antibiotics are widely used in animal husbandry,aquaculture and medical treatment.Due to its advantages of green environment protection,simple reaction conditions and low energy consumption,photocatalysis technology has attracted much attention in the field of antibiotic application in water.W₁₈O₄₉is a kind of wide band gap n-type semiconductor,has the unusual defect structure and near infrared absorption properties of strong.compared with the two kinds of nanostructures,three-dimensional sea urchin structure with high volume,carrier transport way is unique,the advantages of small organic molecules transport way to rich.In this paper,the sea urchin-shaped W₁₈O₄₉matrix was used to enhance its photocatalytic activity in a composite way,and a series of studies were carried out on the difficult problem of quinolone antibiotic removal in medical wastewater.The specific results are as follows:A series of W₁₈O₄₉photocatalysts were prepared using nitrogen-doped carbon quantum dot as crystal seed,WCl₆as precursor and ethanol as solvent under the condition of reaction temperature of 240℃and hydrothermal time of 20 h.The effect of N-CQD_Swith different mass ratio on the morphology of W₁₈O₄₉was investigated.The physical and chemical properties of the catalyst were analyzed by SEM,XRD,XPS,PL and UV-vis.The results show that the material takes on the shape of a sea urchin and has the best performance when adding nitrogen doped carbon quantum dots with a mass ratio of 5%.W₁₈O₄₉（5）showed the best photocatalytic performance under visible and near-infrared light,and its degradation rate was 60.4%and 65.8%,respectively.SEM and XRD results confirmed that the sea urchin W₁₈O₄₉was successfully prepared,and PL and UV-vis showed that the photocatalytic activity of sea urchin W₁₈O₄₉was significantly improved.On this basis,sea urchin W₁₈O₄₉/N-CQD_Sand sea urchin W₁₈O₄₉/NS-CQD_Swere prepared by combining N-CQD_Sand NS-CQD_S.In the experiment,the degradation efficiency of the catalyst for quinolones in water under visible and infrared light was taken as the evaluation index.And by using fluorescence spectroscopy（PL）and uv-vis spectroscopy（UV-Vis）has carried on the test and analysis,the results showed that N-CQDs,NS-CQDs with sea urchin W₁₈O₄₉compound to improve the photocatalytic efficiency,the sea urchin is W₁₈O₄₉/NS-CQDs（3）the best photocatalytic performance,under the condition of visible light and infrared light to 10 mg/L of levofloxacin degradation rate were 70%and 79%respectively;The degradation rate of 10mg/L ciprofloxacin was 73%and 80%,respectively.The degradation rate of 10mg/L norfloxacin was 85%and 90%,respectively.In view of the problems that may be encountered in the actual treatment of antibiotic wastewater,the optimal W₁₈O₄₉/NS-CQD_S（3）was used as a photocatalyst to explore the factors affecting the efficacy,and the influence of p H value was shown to be more conducive to the removal of quinolones when p H value was neutral.Considering the complexity of real wastewater,the experiment of quinolone antibiotic removal was carried out in this paper.When the water quality background was domestic sewage,the removal of quinolone antibiotic could reach 85.1%.Compared with the wastewater containing quinolones in the laboratory,the main reason for the lower removal rate is that the wastewater contains organic matter and inorganic salts which can be used as strong active species capture agents,thus affecting the photocatalytic degradation efficiency.A photocatalytic test was carried out on norfloxacin 10 mg/L by adding a sea urchin-like W₁₈O₄₉/NS-CQD_S（3）photocatalyst.The photocatalytic results of the dynamic reactor showed that the removal capacity of norfloxacin could still reach 82%after 1040 min of circulation in the dynamic reactor.