Permanganate oxidation of polycyclic aromatic compounds (PAHs and polar PACs): column experiments with DNAPL at residual saturation

Abstract

Permanganate is an oxidant usually applied for in situ soil remediation due to its persistence underground. It has already shown great efficiency for dense nonaqueous phase liquid (DNAPL) degradation under batch experiment conditions. In the present study, experimental permanganate oxidation of a DNAPL -coal tar -sampled in the groundwater of a former coking plant was carried out in a glass bead column. Several glass bead columns were spiked with coal tar using the drainageimbibition method to mimic on-site pollution spread at residual saturation as best as possible. The leaching of organic pollutants was monitored as the columns were flushed by successive sequences: successive injections of hot water, permanganate solution for oxidation, and ambient temperature water, completed by two injections of a tracer before and after oxidation. Sixteen conventional US-EPA PAHs and selected polar PACs were analyzed in the DNAPL remaining in the columns at the end of the experiment and in the particles collected at several steps of the flushing sequences. Permanganate oxidation of the pollutants was rapidly limited by interfacial aging of the DNAPL drops. Moreover, at the applied flow rate chosen to be representative of in situ injections and groundwater velocities, the reaction time was not sufficient to reach high degradation yields but induced the formation and the leaching of oxygenated PACs.

Characterization of Dissolved Organic Matter Components of Agricultural Waste Sources in Water Bodies Based on EEMs

“…At present, the research methods on the source and properties of DOM mainly include gas chromatography, nuclear magnetic resonance spectroscopy (NMR), liquid chromatography, ultraviolet spectroscopy (UV-Vis), chromatography-mass spectrometry and three-dimensional fluorescence spectroscopy (3D-EEMs) [2]. According to the existing research, three-dimensional fluorescence spectroscopy is widely used in the determination of amino acids, aromatic hydrocarbons and other DOM with fluorescence spectral characteristics because of its low cost and high efficiency [3][4][5]. Parallel factor analysis (PARAFAC) can resolve the three-dimensional fluorescence spectral characteristics, and fluorescence components for qualitative identification and quantitative analysis [6].…”