A Combined Numerical and Experimental Analysis of Nanofiber Effects on Ion Transport in Nanoporous Composite Membranes

Enhancing ion transport through Metal-Organic-Framework (MOF) membranes is becoming increasingly important in various research fields, such as heavy metal separation from water, CO 2 absorption, and energy conversion. Using two-dimensional metal-organic framework (2D MOF) material has received tremendous attention in the salinity gradient power (SGP) and molecular separation due to its high surface area, tunable pore size, chemical stability, and flexibility. However, low ion flux is crucial yet challenging with standard 2D nanomaterial, due to limited pore, long ion path, and low ion selectivity. The insertion of nanofiber into 2D nanoporous Cu-TCPP membrane can generate interconnections between the interplanar nanofibers and the lamellar 2D nanoporous MOF membrane, introducing a fixed space‑charge density of –1.0×10⁷ C m⁻³ and resulting in increased mechanical strength, ion flux, and ion selectivity compared to the pure 2D MOF membrane. This study focuses on MOF/natural nanofiber membrane applied in converse energy from sustainable resource of seawater and river water. Regarding experiment, green and inexpensive natural-based fiber would be used to synthesize nanofiber (NNF) which are then compounded with 2D nanoporous Cu-TCPP to prepare Cu-TCPP@NNF nanofluidic membranes. The experimental results can be validated by means of COMSOL Multiphysics simulations based on the Poisson-Nernst-Planck and Navier-Stokes equations to indicate the effect of NNF on increasing space charge density and enhancing the ion transport through the membrane. Simulation results show that under a 500/10 mM NaCl gradient, the CuTCPP@NNF membrane delivers an opencircuit voltage (Voc) of 43.6 mV and a shortcircuit current (Isc) of 4.25 mA/m, which are 9% and 21% higher than those of the pristine CuTCPP film (40 mV, 3.5 mA/m). COMSOL simulations replicate experimental diffusion voltage within 1% of errors. These quantitative results demonstrate that NNF integration effectively elevates space charge, amplifies ion‑diffusion‑driven potentials and currents.