Effect of Nonthermal Plasma on Cation Distribution and Photocatalytic Activity of MgFe 2 O 4 Nanoparticles for Dye Degradation Application

Nanophotocatalysts are becoming increasingly popular for removing heavy metals from wastewater, degrading organic pollutants, and producing hydrogen. In this work, MgFe 2 O 4 nanoparticles were prepared by a sol‐gel process to study the photocatalytic degradation of crystal violet (CV), rhodamine blue (RhB), and methylene blue (MB) dyes under sunlight irradiation. The prepared MgFe 2 O 4 nanoparticles were calcined at 500°C and then treated with nonthermal microwave plasma for 60 min. The X‐ray diffraction (XRD) analysis revealed that the crystallinity of plasma‐treated MgFe 2 O 4 nanoparticles increased by showing a different cation distribution compared with plasma‐treated nanoparticles based on the intensity ratios of (220), (400), and (420) diffraction peaks. The intensity ratios of XRD peaks decreased, and the lattice parameter increased after plasma treatment. Crystallite size also increases after plasma treatment. The optical band gap energy of the treated ferrites decreased from 2.21 eV to 2.17, showing increased light absorption in the visible region compared with pristine ferrites. The saturation magnetization of magnetic photocatalysts increased from 40.9 emu/g to 62.16 emu/g after plasma modification. The photocatalytic activity for CV, RhB, and MB degradation increased from 60%, 65%, and 53% to 90%, 91%, and 87% after plasma modification. Plasma treatment enhances dye degradation by promoting the formation of reactive species that can effectively break down the dye molecules.