TY - JOUR
T1 - A benchmark for multi-rate surface complexation and 1D dual-domain multi-component reactive transport of U(VI)
AU - Greskowiak, Janek
AU - Gwo, Jack
AU - Jacques, Diederik
AU - Yin, Jun
AU - Mayer, K. Ulrich
N1 - Score=10
PY - 2015/6/1
Y1 - 2015/6/1
N2 - Nonequilibrium surface complexation reactions have been found to substantially affect U(VI) transport in natural porous media both in laboratory and field scale experiments. Nonequilibrium sorption behavior occurs on multiple time scales and is a result of diffusion-limited transport in immobile intra-grain and intra-aggregate pore water. Experimental data on U(VI) transport was successfully described with a recently developed reactive transport model that accounted for the nonequilibrium adsorption processes through the formulation of a multi-rate surface complexation model treating surface complexation as kinetic reactions. In the present work, a benchmark problem set has been developed for testing existing or newly developed
reactive transport codes on their capability to simulate multi-rate surface complexation and dual-domain multicomponent reactive transport of U(VI). The benchmark problem consists of three individual component problems on the basis of previous studies investigating the desorption of U(VI) from radionuclide-contaminated sediment from the Hanford 300A site, Washington, USA. Starting with a single-domain model considering constant hydrochemical conditions (component problem 1), the complexity of the model was stepwise increased. In the component problem 2 dual-domain first-order mass transfer was added. The principal problem also included dual-domain mass-transfer, but was further extended for changing hydrochemical conditions in the column’s inflow water, which resulted in drastic changes in the U(VI) desorption pattern due to surface complexation reactions. For the three individual component problems, the corresponding simulation results agree very well among four well-known and thoroughly tested independent reactive transport codes, indicating that the proposed benchmark problem set is a suitable test case.
AB - Nonequilibrium surface complexation reactions have been found to substantially affect U(VI) transport in natural porous media both in laboratory and field scale experiments. Nonequilibrium sorption behavior occurs on multiple time scales and is a result of diffusion-limited transport in immobile intra-grain and intra-aggregate pore water. Experimental data on U(VI) transport was successfully described with a recently developed reactive transport model that accounted for the nonequilibrium adsorption processes through the formulation of a multi-rate surface complexation model treating surface complexation as kinetic reactions. In the present work, a benchmark problem set has been developed for testing existing or newly developed
reactive transport codes on their capability to simulate multi-rate surface complexation and dual-domain multicomponent reactive transport of U(VI). The benchmark problem consists of three individual component problems on the basis of previous studies investigating the desorption of U(VI) from radionuclide-contaminated sediment from the Hanford 300A site, Washington, USA. Starting with a single-domain model considering constant hydrochemical conditions (component problem 1), the complexity of the model was stepwise increased. In the component problem 2 dual-domain first-order mass transfer was added. The principal problem also included dual-domain mass-transfer, but was further extended for changing hydrochemical conditions in the column’s inflow water, which resulted in drastic changes in the U(VI) desorption pattern due to surface complexation reactions. For the three individual component problems, the corresponding simulation results agree very well among four well-known and thoroughly tested independent reactive transport codes, indicating that the proposed benchmark problem set is a suitable test case.
KW - groundwater
KW - uranium reactive transport
KW - nonequilibrium mass-transfer
KW - surface complexation
UR - http://ecm.sckcen.be/OTCS/llisapi.dll/open/12031094
U2 - 10.1007/s10596-014-9457-4
DO - 10.1007/s10596-014-9457-4
M3 - Article
SN - 1420-0597
VL - 19
SP - 585
EP - 597
JO - Computational Geosciences
JF - Computational Geosciences
IS - 3
ER -