Sm-Co substituted M-type lead hexaferrite for dielectric properties and visible light driven methylene blue degradation in industrial wastewater.

The rapid industrialization of the world is critically influencing our environment and natural ecosystem. The researchers are taking keen interest to invent novel material as photocatalyst for non-degradable organic pollutants. Herein, we have fabricated Sm and Co substituted M-type hexaferrite with composition Ca_0.5Pb_0.5–xSm_xCo_yFe_12–yO₁₉, (x = 0.00–0.1; y = 0.00–1.00) by sol–gel auto-combustion approach. The effect of Sm2+ and Co3+ substitution in calcium-lead hexaferrite has been investigated for structural, morphological, dielectric and photocatalytic applications for organic pollutants. X-ray diffraction study exhibited the presence of the single-phase M-type hexaferrite with size ranged between 19–23 nm. The particle size, shape and elemental composition were determined by scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis. It was investigated that the electrical resistivity was decreased, and drifts mobility increased with increasing Sm²⁺ and Co³⁺ contents in the doped materials. An inverse relation has been established between the dielectric constant and the dielectric loss up to a frequency of 9.0 GHz and remains constant above this frequency range. The synthesized materials may prove a suitable contender in the domain of high-frequency devices like circulators, filters, transformers and antennas and environmental remediation. The energy bandgap (Eg) was calculated from UV-visible absorbance spectra by Tauc plot. It showed decreasing trend from 2.2 to 1.95 eV for precursor and doped material (Ca_0.5Pb_0.5–xSm_xCo_yFe_12–yO₁₉, x = 0.1; y = 1.00) respectively. Narrowing of bandgap is considered an important factor for the degradation of industrial effluents. The doped materials have also been explored to study the photocatalytic efficiency using a batch reactor to remove methylene blue dye from the textile synthetic wastewater in the presence of visible light radiations at 668 nm, recording 87.50% of degradation efficiency. [ABSTRACT FROM AUTHOR]