Several surface complexation models (SCMs) have been developed over the years to describe interfacial phenomena, and attempted to predict adsorption processes in contaminated sites. However, the high degree of characterization required to describe the sorbate-sorbent system has resulted to over-parametrization, and hindered their application to a larger scale, shifting the field of transport modeling to the traditional distribution factor (Kd). A step towards large scale applications is the development of a SCM database with unified parameters available to transport modelers. A multi-start optimization algorithm (MUSE) has been developed to estimate global surface complexation parameters and a new approach to identify unified equilibrium constants for oxyanion adsorption on a group of iron oxides (ferrihydrite, hematite, goethite) has been demonstrated in previous studies. Following the seminal work of Dzombak and Morel  and Davis et al. , this study is a second attempt to build unified SCMs. The model incorporates the recent findings in spectroscopy and scales up to a group of iron oxides using the component additivity approach. Those objectives are achieved by: a) introducing a 3-site unified model for surface charge, and b) develop a unified SCM to predict U(VI) and Cr(VI) adsorption on the three iron oxides employing a large adsorption dataset.
|Original language||English (US)|
|Title of host publication||V.M. Goldschmidt Conference - Program and Abstracts|
|State||Published - 2018|