Adsorption and photodegrading of Methylene Blue by using of BaLa xGdxFe۱۲-۲xO۱۹ (x=۰.۲, ۰.۴, ۰.۶ and ۰.۸)/PANI nanocomposites

In this paper, a series of BaLa­xGdxFe۱۲-۲xO۱۹ (x=۰.۲, ۰.۴, ۰.۶ and ۰.۸)/PANI (polyaniline) nanocomposites synthesized for investigating the photocatalytic properties. Barium hexaferrite doped with La۳+ and Gd۳+ prepared via a sol-gel auto-combustion method and then the binary nanocomposites fabricated by the in situ polymerization method. (Fourier transform infrared) FTIR, (x-ray diffraction) XRD, (field emission electron microscopy) FESEM and (vibrating sample magnetometer) VSM confirmed the formation of binary nanocomposites. In FTIR analysis, the peaks at ۴۳۱ and ۵۸۰ cm-۱ wavenumbers supported the formation of barium doped hexaferrite. At ۱۴۶۳ and ۱۵۵۴cm-۱ wavenumbers, the formations of quinoid and benzenoid rings were observable. The XRD patterns of nanocomposites proved the formation of PANI by appearing the amorphous peak at ۲θ=۲۳.۰۵ and ۲۶.۰۵ degrees beside the hexaferrite phase. In FESEM pictures, the sphere shape of PANI masked the whole nanoparticles of hexaferrite. In VSM hysteresis loops, by doping La۳+, the saturation magnetization increased to ۷۴ emu. Then, by adding non-magnetic part (PANI) to the magnetic hexaferrite, the saturation magnetization decreased to ۱۱ emu. The photocatalytic properties of samples performed under the irradiation of UV-Vis light. All samples presented the photocatalytic properties. Hexaferrites as a semiconductor generated the electron-hole pairs under irradiation. PANI prevented the accumulation of electron-hole pairs on the valance band and consequently accelerated the photo-degradation of methylene blue. Kinetic studies and calculation of the correlation coefficient (R۲) value which was about ۰.۹۸, proved that the photocatalytic reactions followed the Pseudo-first order kinetic.

Keywords:

Hexaferrite , Methylene Blue , PANI , Photocatalytic Property , Saturation Magnetization