Electrokinetic removal of creosote from treated timber waste: a comprehensive gas chromatographic view

The applicability of electro-remediation to remove creosote contaminants from treated wood wastes and to assess the behaviour of its components when submitted to an electric field was studied on woodchips from treated railway sleepers of Pinus pinaster Ait. 15 days experiments were performed using a laboratory cell, with constant current density set at 0.2 mA cm−2 and an open electrolyte flow rate of 0.5 mL min−1. The anolyte and catholyte solutions were collected and extracted by solid phase extraction. The resulting extracts were analysed by one dimensional gas chromatography hyphenated with mass spectrometry (1D-GC/MS) and comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC/TOFMS). The chemical groups of creosote components were identified and its behaviour on process described. Polycyclic aromatic hydrocarbons, phenols and the majority of the S- and O- heterocycles were found to move in the electrokinetic cell towards the anode compartment, due to electroosmosis, whereas the majority of the positively charged N-heterocycles (aza-heterocycles) moved towards the cathode compartment, due to electromigration.