Uranyl adsorption onto hydrous ferric oxide-A re-evaluation for the diffuse layer model database.

The diffuse layer model (DLM) database of Dzombak and Morel was developed to quantify the adsorption of dissolved species onto the hydrous ferric oxide (HFO) surface, and contained numerous surface complexation reactions, including surface complexation reactions for uranyl (UO(2)(+2)) consisting of Hfo_sOUO(2)(+) and Hfo_wOUO(2)(+). However, these constants were not based upon experimentally obtained data, but rather were derived from linear free energy relationships (LFER) using log K(MOH) values. When compared to experimental data, the LFER-derived constants for uranyl were shown to overestimate adsorption by a factor of 10 in some cases.