CVEN 6414 Aquatic Surfaces and Particles

Problem Set 5: Cation Binding to Dissolved Organic Matter

 

 

Ranville et al. (2007) examined the association of uranium(VI) with dissolved organic matter from some pore water samples from a glacial till.  Using flow field-flow fractionation, ICP-MS, and UV spectroscopy, they showed that only about 2% of the uranyl ions were bound to the dissolved organic matter.

Use Visual MINTEQ to calculate the speciation of uranyl in a solution representing the pore waters examined by Ranville et al. (2007).  Use the groundwater chemical analyses for the 2.3 m depth in the oxidized till.  Using a dissolved organic carbon concentration of 132 mg L-1 and a uranium concentration of 603 ppb.  Assume that all of the uranium is present as U(VI), the uranyl ion (UO22+).  The dissolved organic matter will be included in the model as the set of ligands described in Table 3.

Can you match the experimental results of Ranville et al. (2007) -- that only about 2% of the uranium is bound to the dissolved organic matter?
 


Last updated on May 22, 2007 by Joe Ryan