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

The removal of gas environmental pollutants from their gaseous state using electrochemical methods is a futuristic technology. The effective migration of ions to the electrode without liquid electrolyte plays a key role in facilitating the removal from the gaseous state. In this study, a poly(vinyl alcohol)-sodium silicate gel membrane and a cobalt-modified graphitic carbon nitride (Co-GCN) electrode were developed for the mineralization of a common air pollutant, acetaldehyde (AA). Confocal laser microscopy, electrochemical impedance spectroscopy, and SEM-EDS analysis demonstrated that the as-prepared gel membrane stably conducts ions with lower resistance. The analysis of Co-GCN using XRD, FTIR, and cyclic voltammetry show a possible coordination of cobalt ions with GCN. At a given applied potential of 0.8 V, 82% removal of AA (80 ppm in 1 h) was achieved. The electron transfer kinetics follow pseudo-first-order kinetics, as the variation in the removal rate is less over a wide range of AA feed concentrations. For applied potentials above 1 V, the complete formation of CO₂ was equivalent to AA removal, with a formation capacity of 1.37 g cm^-2 h^-1. The seed of this first attempt at gaseous AA mineralization may open a new way to remove environmental gaseous pollutants.