Adsorption of methylene blue surface by g-C3N4 based on attenuated total reflection LED spectroscopy
With SiO2 photoconductive fiber as the carrier,g-C3N4 was loaded on the surface of SiO2 opti-cal fiber to form a uniform film by sol-gel method.The samples were characterized by X-ray diffraction(XRD),infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),transient fluorescence spectrosco-py(PL),fluorescence electron microscopy(LSCM),Zeta potential and other characterization techniques.The re-sults showed that g-C3N4 was evenly distributed on the surface of SiO2 optical fiber.After adsorption of meth-ylene blue molecules,the Zeta potential increased from-45.35 mV to-28.72 mV.The absorption peak at 700 cm-1 in FT-IR spectrum moved to 667 cm-1,and the absorption peak at 600 cm-1 disappeared.The typical emission peak of PL spectroscopy decreased significantly,indicating that g-C3N4 had good adsorption capacity for methylene blue molecules.The surface adsorption of methylene blue on g-C3N4 was studied using red LED as light source and photomultiplier tube as detector by using the characteristics of SiO2 optical fiber and the principle of attenuated total reflection spectroscopy.The experimental results were fitted by Freundlich iso-therm adsorption model and Langmuir isotherm adsorption model.The results showed that the adsorption of methylene blue molecules by g-C3N4 was more in line with the Langmuir isothermal adsorption model,which belonged to single-layer adsorption rather than multi-layer adsorption.
attenuated total reflection LED spectroscopyg-C3N4SiO2 optical fibermethylene bluesurface adsorption
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