Advances in magnesium spinel ferrites for photocatalytic degradation of methylene blue: Challenges and future prospectives

• A comprehensive overview of Mg-based spinel ferrite based photocatalysts for the dye degradation. • Summarization of advantages and disadvantages of synthesis approaches for making Mg-spinel ferrites. • Critical analysis on the recent works in the field of MB dye degradation. • Detailed analysis on impact of structure, morphology, reaction condition and catalytic dosage on methylene blue degradation. • Deeper insights on the mechanism followed during the MB degradation. • Recent literature analysis and future recommendation for photocatalytic applications of Mg-spinel ferrites. Spinel ferrites have been found to be a promising material for water purification because of their large surface area, tunable traits, high chemical stability and excellent magnetic traits. Their multifunctionality and ease of magnetic separation enable rapid adsorption and efficient decomposition of contaminants, including dyes, pharmaceuticals, and heavy metals. Furthermore, MgFe 2 O 4 and its carbon-based composites exhibit strong photocatalytic activity under visible and UV light, generating reactive radicals for effective pollutant degradation. Despite these advantages, their practical application remains constrained by an incomplete understanding of adsorption and degradation mechanisms. This paper highlights key variables that influence photocatalytic efficiency, including pH, pollutant concentration, and reaction time, while also examining the role of synthesis strategies, elemental substitutions, and surface modifications in enhancing efficiency. In addition, this review paper focuses on the different fabrication approach, decomposition of methylene blue dye by photocatalysis, research gap, and the application of MgFe 2 O 4 .