Optimization of Fe3O4/SiO2/N-TiO2/Ag/AgCl core-shell nanomaterial and its properties, repeatability and photocatalytic mechanism
In this study, the magnetic core-shell nanomaterial Fe 3 O 4 /SiO 2 /N-TiO 2 /Ag/AgCl (FSNT/Ag/AgCl) that efficiently degraded methyl orange (MO) was produced. The dosages of tetrabutyl titanate (TBOT), urea and AgNO 3 were optimized by response surface methodology (RSM). Scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy analysis (XPS), energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), fourier transform infrared spectrometer (FT-IR), and UV–vis diffuse reflectance spectrum (UV–vis DRS) were used to characterize the nanomaterial. The particle size of FSNT/Ag/AgCl was 91.98 nm, and it presented a core-shell structure with Fe 3 O 4 as the core, SiO 2 and N-TiO 2 wrapped in Fe 3 O 4 , and Ag/AgCl deposited on the outermost layer. Performance and mechanism research experiments showed that under the optimized conditions of 1 g/L FSNT/Ag/AgCl, pH = 9, temperature of 35℃ and initial MO concentration of 10 mg/L, about 90 % of MO was degraded in 20 min. The mineralization rate was 35.2 % within 120 min. Holes (h + ) and superoxide anions (·O 2 − ) were the main active substances in the whole photocatalytic degradation. FSNT/Ag/AgCl could be recovered by magnet. After 5 repeated experiments, the degradation rate of MO within 100 min still reached 88.5 %. This work provides a recyclable core-shell nanomaterial for faster degradation of dye wastewater.
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