Semi-solid State PVA-Sodium Silicate Gel Membrane\nCell for Electrochemical Oxidation of Gaseous Acetaldehyde at Cobalt\nImmobilized Graphitic Carbon Nitride Electrode

The\nremoval of gas environmental pollutants from their gaseous\nstate using electrochemical methods is a futuristic technology. The\neffective migration of ions to the electrode without liquid electrolyte\nplays a key role in facilitating the removal from the gaseous state.\nIn this study, a poly(vinyl alcohol)-sodium silicate gel membrane\nand a cobalt-modified graphitic carbon nitride (Co-GCN) electrode\nwere developed for the mineralization of a common air pollutant, acetaldehyde\n(AA). Confocal laser microscopy, electrochemical impedance spectroscopy,\nand SEM-EDS analysis demonstrated that the as-prepared gel membrane\nstably conducts ions with lower resistance. The analysis of Co-GCN\nusing XRD, FTIR, and cyclic voltammetry show a possible coordination\nof cobalt ions with GCN. At a given applied potential of 0.8 V, 82%\nremoval of AA (80 ppm in 1 h) was achieved. The electron transfer\nkinetics follow pseudo-first-order kinetics, as the variation in the\nremoval rate is less over a wide range of AA feed concentrations.\nFor applied potentials above 1 V, the complete formation of CO<sub>2</sub> was equivalent to AA removal, with a formation capacity of\n1.37 g cm<sup>–2</sup> h<sup>–1</sup>. The seed of this\nfirst attempt at gaseous AA mineralization may open a new way to remove\nenvironmental gaseous pollutants.