Karadağ E., Ekinci Z.
Journal of Brilliant Engineering (BEN), cilt.7, sa.1, ss.1-11, 2026 (Hakemli Dergi)
Özet
Electrospun PVDF/GO/CNT nanofiber membranes were produced and evaluated as adsorbents for the removal of methylene blue (MB) from water. Adsorption tests were carried out in batch mode and the effects of pH, contact time, initial concentration, membrane dosage, and temperature were examined. The uptake showed a clear dependence on pH, with the highest performance obtained near pH 8. Under the representative conditions (C₀ = 100 mg L-1, V = 100 mL, m = 0.03 g, 25 °C, 60 min), the membrane adsorbed about 280 mg g-1, corresponding to roughly 84% removal. Equilibrium was reached within approximately one hour, and subsequent experiments were conducted at 25 °C. The kinetic data were fitted satisfactorily by the pseudo-second-order model; however, this model is used only as a fitting tool and not as proof of a specific rate-controlling mechanism. Among the equilibrium models tested, the Freundlich equation provided the best description of the data, indicating adsorption on a heterogeneous surface. Thermodynamic evaluation yielded negative ΔG° values and a positive ΔH° (46.7 kJ mol-1), showing that the process is spontaneous and endothermic within the studied temperature range. In contrast to studies that examine only PVDF/GO or PVDF/CNT systems, the present work investigates the combined use of GO and CNT in a single electrospun membrane and shows that their coexistence enhances MB uptake. These findings suggest that the PVDF/GO/CNT membrane is a workable material for MB removal from aqueous solutions.