Electron Transport and Redox Chain Reactions in a Mosaic Membrane

Abstract

A circulating current enhances transports of ions and electrons in a mosaic membrane system with ion-exchange membranes and electron-transport membranes. Electron transport is readily coupled to ion transport in a new mosaic membrane with electron-transport regions and ion-exchange regions. Electrons and ions are transported in the same or opposite direction by the driving forces of the redox potential gradient or the concentration gradient. Redox chain reactions are also generated in the mosaic membrane system as the electron flow in biological membranes.

Redox Reactions without Direct Contact of the Reactants. Electron and Ion Coupled Transport through Polyaniline Membrane

“…The concentrations here are not given in the unit of mol/ cm 2 , as is common for example in the heterogeneous catalysis but in mol/cm 3 . This is possible because the redox reactions in the case of polyaniline are taking place not only on the surface but also inside the polymer, where electroneutrality is possible because of the simultaneous transport of electrons (redox equivalents) and ions in the synthetic metal materials.…”

“…At high HCl concentration the membrane is more permeable to anions; therefore probably anion insertion is the dominating process (eq 5). 13 Electron transfer for the oxidant/PANI membrane interface can be expressed as [Am] o : specific content of amine nitrogen in the membrane near the surface facing oxidant solution, mol/cm 3 ; k o : rate constant of amine nitrogen oxidation, cm 4 /(s mol); F o : electron flux at the oxidant/membrane interface, mol/(s cm 2 ), equal to the rate of Fe 3+ reduction.…”

“…1,2 In some other cases, for example in liquid membranes with mobile derivatives of ferrocene, electron transport is coupled with counter transport of anions through the membrane into opposite direction. [3][4][5] Another possible option to conduct transmembrane redox reactions could be based on electroconductive polymer membranes, for example polyaniline. Redox properties of polyaniline (PANI) have been intensively investigated and characterized by XPS, cyclic voltammetry, and impedance.…”

“…Transmembrane redox processes are extremely important in biological systems, and the most well-known examples are cellular respiration and photosynthesis. It was possible to imitate some physicochemical aspects of these processes using polymer supported liquid membranes with quinones serving as mobile carriers in a coupled electron and proton co-transport in the same direction across the membrane. , In some other cases, for example in liquid membranes with mobile derivatives of ferrocene, electron transport is coupled with counter transport of anions through the membrane into opposite direction. − …”

Ion/Electron Coupled Transport Through Polyaniline Membrane: Fast Transmembrane Redox Reactions at Neutral pH

“…1,2 Electron and ion coupled transport was described for several other artificial membranes, including redox papers describing redox processes through electroconductive polymers. [3][4][5][6][7][8][9][10] Previously we have demonstrated possibility of electron/Clcoupled counter transport through HCl doped polyaniline (PANI) membrane (Figure 1), but the process was observed only at acidic pH. 5,6 In this work, we describe a similar process through the camphor sulfonic acid (CSA) doped PANI membrane.…”