Description
Macromolecular natural organic matter (NOM, e.g. humic acids) and iron oxide nanoparticles are ubiquitous carriers for trace elements in aquatic systems. In shallow sunlit environments, NOM is bleached, its concentration decreases, and iron minerals are reductively dissolved due to photochemical reactions, This study aims at investigating the fate of metals adsorbed/complexed to these colloids. Metal distribution as a function of particle size of irradiated and non irradiated soil extract samples and peat bog water samples were analyzed by Field Flow Fractionation (FFF) coupled with Inductively Coupled Plasma Mass Spectroscopy (ICPMS). We show that trace elements are attached to a smaller group of NOMiron complexes and in some samples also to a larger sized group indicative of iron oxide colloids in unirradiated samples. First irradiation experiments show that dissolved organic carbon (DOC) concentrations decrease during irradiation, as indicated by the decrease of UV adsorption at 260 nm. Iron concentrations decrease both in the NOM as well as in the proposed iron oxide colloid domain. Trace elements redistribute in the different size domains, depending on the pH at which the experiment has been performed. While FFF recovery rates for UV-VIS are excellent (~90%) the recovery for the fluorescence signal characteristic for the smaller organic molecules (fulvic acids) is low (app. 30%), when a 1000 g/mol MWCO membrane is used in FFF analytics. To approach quantitative recovery rates for the low molecular weight fraction, membranes with lower MWCO, as well as size exclusion chromatography, a technique more applicable to smaller sized molecules than FFF, will be applied.| Period | 2010 |
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| Event title | 5th Annual International Conference on Environmental Effects of Nanoparticles and Nanomaterials |
| Event type | Conference |
| Location | Clemson, United StatesShow on map |