photocatalytic characteristics of bifeo3 nanopowder synthesized via mechanothermal route

The discharge of various textile industry wastes into water bodies has become a significant global issue. methylene blue (mb) dye, a popular cationic dye, is both carcinogenic and mutagenic, and it is environmentally persistent and toxic. due to its extensive industrial usage, a substantial amount of wastewater containing methylene blue dye is released into groundwater and surface water. to address this environmental concern, researchers have turned to photocatalysis, an appealing method for treating water due to its use of clean and renewable solar energy. photocatalytic degradation is an advanced process of oxidation capable of breaking down high concentration pollutants with low biodegradability and complexity, using light energy to drive pollutant degradation. currently, the synthesis of single phase bifeo3 ceramics is a challenging issue. different techniques, such as solid state and wet chemical methods, have been developed to synthesize nanosized bifeo3 ceramics. the solid state route, which involves calcining a mixtur of bismuth oxides and iron oxides, is the most widely used technique for producing perovskite type structure materials like bifeo3. in this study, the high energy ball milling followed by high temperature heat treatment, resulted in the successful synthesis of bifeo3 nanopowder, this method has the advantage of large scale and low cost production. the process began with the accurate weighing of a stoichiometric equimolar mixture of α-bi2o3 and α-fe2o3 materials, followed by 20 hours of milling in the planetary high energy ball mill in air. the optimal heat treatment temperature for obtaining almost single phase powder was determined to be 750°c for 1 hour. the resulting bifeo3 nanopowder exhibit promising properties due to their multiferroic nature, unique crystal structure, and ability to absorb visible light in the solar spectrum. extensive characterization was performed on the samples including x-ray diffraction (xrd) analysis, field emission scanning electron microscopy (fesem), and diffuse reflectance spectroscopy (drs). the use of 78.07 kj/g energy during milling resulted in the creation of an amorphous structure, but the heat treated sample displayed numerous sharp and overlapping reflections without any amorphous-like background intensity in their patterns. calculations using the scherrer’s equation revealed average crystallite sizes of 41 nm for the mechanothermally synthesized sample. by employing the tauc method, the optical band gap (eg) of the bifeo3 sample was determined to be 2.21 ev. remarkably, the produced sample exhibited degrading 70% of the methylene blue dye within 300 minutes at a catalyst dosage of 4.0 g/l. the rate constant (k value) for the sample was calculated to be 0.00356 (1/min). these results highlight the significant impact of milling and heat treatment on the surface area and optical properties of bifeo3 nanopowder. platelike or flaky matter can be observed forming.