Abstract

Developing sustainable, metal-free photocatalytic systems for wastewater remediation remains challenging: powdered photocatalysts agglomerate in aqueous media, lose active surface area, and are difficult to recover. Herein, we report g-C₃N₄/cellulose acetate (CA) nanofibrous membranes fabricated via electrospinning as a solution for continuous water treatment, evaluated using methylene blue (MB) as a model probe. Graphitic carbon nitride (g-C₃N₄) nanosheets, characterized by a 2.73spaceeV band gap and a layered polymeric structure, were embedded into CA nanofibers to overcome these dispersibility and recovery barriers. FTIR shifts of the CO and s-triazine modes revealed an interfacial interaction between g-C₃N₄spaceand the CA matrix, indicating intimate coupling rather than simple physical entrapment, while the electrospun architecture provided hierarchical porosity maximizing light harvesting and mass transfer. Scavenger assays identified superoxide radicals (center dot O₂(-)) as the primary reactive species, with a secondary contribution from singlet oxygen (O-1₂), consistent with a reductive oxygen-activation pathway imposed by the band structure of g-C₃N₄. Key achievements are: (i) a fully organic, metal-free membrane obtained by a single-step, scalable route; (ii) 98.7% MB degradation within 240spacemin under visible light (k_appspace= 1.67spacex 10(-2)spacemin(-)(1)), similar to 2-fold higher than pristine g-C₃N₄ and 1.5-14 times higher than phase-inversion CA membranes loaded with ZnO, TiO₂spaceor CeO₂; (iii) a 63% increase in dark MB uptake versus pristine CA, pre-concentrating the dye at catalytic sites; (iv) stable operation across a broad alkaline window (pH 8-10); and (v) solvent-free, light-driven regeneration preserving >space97% activity over five cycles. These membranes are directly applicable as reusable, metal-free modules for textile-effluent decolorization under solar/visible illumination.