Synthesis of poly (vinylpyrrolidone)/Fe3O4@SiO2 nanoporous catalyst by γ-rays and evaluation their sono-photo-Fenton degradation of toluidine blue under magnetic field

Nanoporous of poly (vinylpyrrolidone)/Fe3O4@SiO2 has been synthesized using ultrasonic-assisted-gamma irradiation technique and characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM)/energy-dispersive spectroscopy (EDX), Fourier transform infrared (FTIR), X-ray diffraction (XRD), Vibrating Sample Magnetometer (VSM), and Brunauer-Emmett-Teller (BET). The efficiency evaluation of PVP/Fe3O4@SiO2 nanoporous catalyst for degradation of toluidine blue (TB) by sono-photo-Fenton (US/UV/FE) processes has been investigated using modified reactor under the influence of magnetic field (MF) 250 Gauss. PVP molecules prevent ions leaching and render Fe3O4@SiO2 nanoparticles to bind with pollutant molecules. Comparative effect of sonication assists on photo-Fenton processes has been studied. The TB degradation was examined at different pHs and H2O2 concentration. After 60 min, the photo-catalytic degradation rate of TB is attained to optimum value (83%) at pH 4. The photo-Fenton catalytic degradation rate of TB decreased (36.39%, 31.84%, and 23.92%) within (0.5, 1.0, and 1.5 M) of H2O2, respectively. The degradation of TB by sono-photo-Fenton process was 76.55 and 95.3% after 60 and 10 min in absence and presence of MF, respectively. Negligible amounts of Fe leaching from PVP/Fe3O4@SiO2 confirm high stability in oxidation systems. BET surface area and pore volume of PVP/Fe3O4@SiO2 were 43.50 m(2) g(-1) and 0.1798 cm(3) g(-1), respectively, with pore size distribution of 16.53 nm indicating their nanoporosity structure. Herein, the novelty is evaluated through the effect of MF and ultrasound-assisted photo-Fenton system for TB degradation using novel PVP/Fe3O4@SiO2 nanoporous catalyst that easily recovered from the reaction solution by external magnet. The PVP/Fe3O4@SiO2/US/UV/FE/MF hybrid system can be introduced as a successful advanced treatment process for degradation of dyes from wastewater with high degradation efficiency in short time.

Automated summary

The synthesis and characterization of nanoporous PVP/Fe3O4@SiO2 using ultrasonic-assisted-gamma irradiation technique was studied. The catalyst showed high efficiency in degrading toluidine blue, and the presence of PVP molecules prevented ions leaching and enhanced binding with pollutant molecules. The effects of ultrasound assistance on the photo-Fenton process were also investigated.