Exploring how organic matter controls structural transformations in natural aquatic nanocolloidal dispersions
King, Stephen M.; Jarvie, Helen P.. 2012 Exploring how organic matter controls structural transformations in natural aquatic nanocolloidal dispersions. Environmental Science & Technology, 46 (13). 6959-6967. 10.1021/es2034087Full text not available from this repository.
The response of the dispersion nanostructure of surface river bed sediment to the controlled removal and readdition of natural organic matter (NOM), in the absence and presence of background electrolyte, was examined using the technique of small-angle neutron scattering (SANS). Partial NOM removal induced aggregation of the mineral particles, but more extensive NOM removal restored colloidal stability. When peat humic acid (PHA) was added to a NOMdeficient sediment concentration-related structural transformations were observed: at 255 mg/L PHA aggregation of the nanocolloid was actually enhanced, but at 380 mg/L PHA disaggregation and colloidal stability were promoted. The addition of 2 mM CaCl2 induced mild aggregation in the native sediment but not in sediments with added PHA, suggesting that the native NOM and the PHA respond differently to changes in ionic strength. A first attempt at using SANS to directly characterize the thickness and coverage of anadsorbed PHA layer in a natural nanocolloid is also presented. The results are discussed in the context of a hierarchical aquatic colloidal nanostructure, and the implications for contemporary studies of the role of dissolved organic carbon (DOC) in sustaining the transport of colloidal iron in upland catchments.
|Programmes:||CEH Topics & Objectives 2009 onwards > Water|
|Additional Keywords:||organic matter, aquatic, nanocolloidal, NOM, natural organic matter, SANS, small-angle neutron scattering|
|NORA Subject Terms:||Chemistry|
|Date made live:||10 Oct 2012 15:02|
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