Upcycling agro-waste as a physical template for synthesizing self-doped Fe₂O₃ and CuO nanoparticles: Assessing...

Instituting an environmentally sustainable and industrially viable method for generating photocatalytic nanoparticles (NPs) through green synthesis is highly challenging due to the complexity of the current protocols. The present study thus investigated the utility of banana flower perianth, a non-edible agro-waste with self-assembled microporous architecture, as a physical template to synthesize Fe₂O₃ and CuO NPs through one-pot synthesis. The synthesized NPs were spherical and highly crystalline. The dye degradation (methylene blue and reactive red 198) efficiency of the NPs was attributed to in-situ doping (potassium from the perianth) from the template. Both the NPs favored the photo-self-Fenton process. Singlet oxygen was characterized as the primary reactive species responsible for the photocatalytic efficiency. The catalyst dose and the initial dye concentration were identified to be the most influential variables by OFAT design and validated by Taguchi design. The NPs sustained their efficiency up to 5 cycles owing to higher surface area (11.84 and 12.57 m²/g). The lower band gap values (Eg = 1.48 and 1.64 eV) corroborated their superiority against commercial NPs even under solar light. Moreover, the NPs degraded tetracycline within 80 min, validating their versatility. Safety assessment of the NPs and the remediated water with Brassica nigra revealed their non-toxic nature. This study thus authenticated the potential of porous plant structures in the sustainable industrial production of visible light responsive NPs.