Development of techniques for purification of waste waters: removal of pyridine from aqueous solution by adsorption at high-area C-cloth electrodes using in situ optical spectrometry

The adsorption and electrosorption/desorption behavior of pyridine (Py) was studied for potential applications to the purification of industrial waste-waters. The use of high-area carbon cloth (C-cloth) electrodes as quasi-3-dimensional interfaces, coupled with in situ UV–Vis spectrophotometric techniques and scanning kinetics for quantitatively monitoring the adsorption/desorption processes and simultaneously obtaining kinetic parameters are described. The conversion of Py to PyH+, which decreases the removal efficiency, takes place in non-buffered electrolyte solution due to pH changes but is eliminated in a HOAc+NaOAc buffer (pH 6.8) solution. Rapid and complete removal of Py is then achieved by anodic polarization. Under controlled potential, Py removal rates are lower than those for galvanostatic polarization where changes of potential arise due to double-layer charging.