Numerous studies were conducted to investigate the mode of sorption (absorption versus adsorption) of organic contaminants on organic matter in soils and sediments. However, the underlying mechanisms involved in the sorption processes were so far mainly addressed with indirect methods and interpretations about interactions between solutes and sorbents were predominantly derived from macroscopic observations. Here we propose analytical techniques that operate at the subparticle scale to provide evidence for the involved sorption mechanisms based on direct observations of the chemical distribution. By combining the chemical information derived from scanning transmission x-ray microscopy (STXM) with the physical information derived from transmission electron microscopy (TEM) we could show that the distribution of hydrophobic organic contaminants follows the porous structure on activated carbon. Furthermore, confocal Raman spectromicroscopy revealed a homogeneous distribution of the same sorbates on organic polymers (polyoxymethylene). These results confirm different sorption mechanisms on the different sorbents.

Application of analytical microscopy techniques for the elucidation of modes of sorption

245th National Meeting (2013)

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