Papers by Keyword: Ion Transport

Abstract: Enhancing ion transport through Metal-Organic-Framework (MOF) membranes is becoming increasingly important in various research fields, such as heavy metal separation from water, CO₂ 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.

Abstract: Fourier Transform Infrared (FT-IR), was applied to investigate the complexation, structural, ionic transport properties and dominant charge carrier species in Chitosan (CS) / Methyl Cellulose (MC) blend doped with 1 – butyl – 3 – methylimidazolium bis (trifluorosulfonyl) imide (BMIMTFSI) solid biopolymer electrolytes (SBEs) which have been prepared via solution casting technique. Samples were partially opaque in appearance with no phase separation. The occurrence of interactions between the host polymer CS/MC blend and ionic dopant BMIMTFSI were proven by FT-IR analysis from the shift in C-O band in 1049 cm^-1. The FTIR spectrum in the region between 1080 and 980 cm⁻¹ were deconvoluted using Origin 8 software to disclose the percentage of free mobile ions and contact ion of the samples. Ionic transport properties analysis reveals that the ionic conductivity is dependent on the ionic mobility (μ) and diffusion of ions (D).Keywords: Biopolymer Electrolyte; Polymer Blend; Chitosan, Methylcellulose; BMITFSI; Ion transport.

Abstract: Re-examination of published conductivity spectra for 2Ca (NO₃)₂∙3KNO₃ (CKN) in its molten and glassy states, in terms of the MIGRATION concept, has brought to light new links between elementary processes occurring within one picosecond and their successful outcomes, i.e. those which determine the DC conductivities. The starting point of this analysis is the transition at 378 K, which arises from a change from a decoupled to a coupled transport mechanism. Remarkably, while there is a change in the shape of the conductivity dispersion and a jump in its onset frequency, there is no change in the temperature dependence of DC conductivity. What emerges from the analysis is a surprising continuity in high-frequency behaviour, with the activation energy and volume for elementary displacements, E_ed and V_ed, remaining constant from 300 K in the glass up to 500 K in the melt. The ratio, E_ed/V_ed, turns out to be equal to our previously defined DC activation moduli for CKN, given by E_DC(T)/V_DC(T) and T_g/(dT_g/dp) for charge transport in the melt and structural relaxation at T_g, respectively. It seems that, at very short times, molten CKN behaves just like an elastic solid. The importance of elastic forces for ionic transport in CKN is corroborated by the finding that the published value of the high-frequency shear modulus of glassy CKN, G_¥, matches those of E_ed/V_ed and hence of both activation moduli. The detected continuity in the picosecond behaviour of CKN across the glass transition could provide a new link between fragile liquids and glassy materials in general.

Abstract: The chemical and mechanical stability of membrane play a important role for understanding the mechanism and applications of cobalt tungstate cation exchange membrane. The PVC based cobalt tungstate (CT) membrane has been prepared by different methods like sol-gel, die-casting and others material processing techniques. It has been prepared through the mixing of PVC with cobalt tungstate into a definite ratio (1:3) that shows good mechanical stability. Moreover, the paper is concerned with physico-chemical and electro-chemical characterization of membrane, namely fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical studies. The results of characterization and electrochemical studies offered the potential industrial applications of membrane in different areas.

Abstract: All-solid-state composite polymer electrolyte is a multiphase material that adopted an organic polymer as the main matrix. Performance improvement of electrolyte materials can be achieved by complexation between functional groups from the polymer molecular chain and the ions and, by adjusting the component and proportion of polymer and modified filler. This manuscript presents a new idea for preparation composite polymer electrolyte based on the poly (ethylene oxide). We use scanning electron microscopy (SEM), AC impedance measurements etc. to character the polymer electrolyte and their properties. We observed a very large improvement of ion conductivity by adding appropriate content of dropping fillers.

Abstract: Motivation for this work comes from the application of the inverse method to electrochemical systems. The basic process operating in these systems is electrodiffusion, which can be described by the full form of the Nernst-Planck and Poisson equations. No simplification like electroneutrality assumption is used. Numerical procedure based on the method of lines (MLs) for time dependent electrodiffusion transport is presented with any number of ionic species. The resulting system of ODEs is effectively solved by employing different integrators (Radau IIA, Rosenbrock, SEULEX). Selected electrochemical systems (liquid junction, bi-ionic case, ion selective electrodes (ISE)) are treated. Performance of the integrators is compared.