Bimetallic Mn-MIL-53(Fe) Metal–Organic Framework Photo-Fenton Catalyst for Elimination of Crystal Violet in Aqueous Solution

Bimetallic Mn-doped MIL-53(Fe) metal–organic framework (MOF) has been developed to remove crystal violet (CV) efficiently from wastewater through the photo-Fenton process. The key innovation of the work lies in enhanced visible light activity, lesser H₂O₂ oxidant content, and faster removal with less sludge generation. Comprehensive characterizations revealed a lower bandgap and rapid charge separation, which reflected on the improvement of the performance of the photocatalyst. The bimetallic MOF achieved 99.01% removal of CV under the visible 100 W Xe light source with six times faster rate than the pristine MIL-53(Fe) and also 82.42% CV removal under irradiation of sunlight in 60 min at optimized conditions of 20.0 ppm dye concentration, 444 ppm H₂O₂ concentration, and 1.0 g/L catalyst loading. The composite maintained good recyclability up to five consecutive cycles with a removal of 78.89% CV. The treated effluent exhibited lower toxicity in seed germination tests, demonstrating the potentiality of Mn-doped MIL-53(Fe) as a stable and efficient catalyst for wastewater treatment.