Eco-Friendly Synthesis of Ba/Sr-Hexaferrites and Their Photocatalytic Performance in Water Remediation

In the present study, M-type barium-doped and strontium-doped hexaferrites (Ba@HF and Sr@HF) were synthesized using a green auto-combustion route, providing an environmentally friendly method for preparing sophisticated ferrite-based materials. Powder X-ray Diffraction (P-XRD), FTIR spectroscopy, FESEM, Energy Dispersive X-ray Spectroscopy (EDS), and UV-Vis spectroscopy were used to systematically characterize the structural, morphological, compositional, and optical properties of the synthesized hexaferrite. The photocatalytic performance of the prepared hexaferrites was tested using diclofenac, a recalcitrant drug pollutant of increasing environmental importance. Photocatalytic experiments indicated that both Ba@HF and Sr@HF showed good degradation under optimized conditions, achieving 94.99% and 96.45% diclofenac degradation, respectively, within 120 min, and both followed pseudo-first-order kinetics. Sr@HF also exhibited a larger apparent rate constant (0.0216 min^-1) than Ba@HF (0.0133 min^-1), which shows better photocatalytic activity. This improvement in performance was explained by increased charge separation, more effective harvesting of visible light, and the production of reactive oxygen species that catalyze the mineralization of pollutants. The catalysts were also found to be stable and reusable, thus indicating that they are viable. These major conclusions indicate that M-type hexaferrites produced via green synthesis are promising multifunctional materials for sustainable environmental remediation and high-level water treatment via photocatalytic processes.