caa a22 4500 463162765 CHVBK 20180406164752.0 cr unu---uuuuu 170326e20070801xx s 000 0 eng 10.1007/s11242-006-9065-4 doi (NATIONALLICENCE)springer-10.1007/s11242-006-9065-4 A semi-analytical solution for linearized multicomponent cation exchange reactive transport in groundwater [Elektronische Daten] [Javier Samper-Calvete, Changbing Yang] Cation exchange in groundwater is one of the dominant surface reactions. Mass transfer of cation exchanging pollutants in groundwater is highly nonlinear due to the complex nonlinearities of exchange isotherms. This makes difficult to derive analytical solutions for transport equations. Available analytical solutions are valid only for binary cation exchange transport in 1-D and often disregard dispersion. Here we present a semi-analytical solution for linearized multication exchange reactive transport in steady 1-, 2- or 3-D groundwater flow. Nonlinear cation exchange mass-action-law equations are first linearized by means of a first-order Taylor expansion of log-concentrations around some selected reference concentrations and then substituted into transport equations. The resulting set of coupled partial differential equations (PDEs) are decoupled by means of a matrix similarity transformation which is applied also to boundary and initial concentrations. Uncoupled PDE's are solved by standard analytical solutions. Concentrations of the original problem are obtained by back-transforming the solution of uncoupled PDEs. The semi-analytical solution compares well with nonlinear numerical solutions computed with a reactive transport code (CORE2D) for several 1-D test cases involving two and three cations having moderate retardation factors. Deviations of the semi-analytical solution from numerical solutions increase with increasing cation exchange capacity (CEC), but do not depend on Peclet number. The semi-analytical solution captures the fronts of ternary systems in an approximate manner and tends to oversmooth sharp fronts for large retardation factors. The semi-analytical solution performs better with reference concentrations equal to the arithmetic average of boundary and initial concentrations than it does with reference concentrations derived from the arithmetic average of log-concentrations of boundary and initial waters. Springer Science+Business Media, Inc., 2006 Cation exchange nationallicence Analytical solution nationallicence Similarity transformation nationallicence Reactive transport nationallicence Taylor expansion nationallicence CORE2D nationallicence Samper-Calvete Javier E.T.S. Ingenieros de Caminos, Canales y Puertos, Universidad de A Coruña, 15192, A Coruña, Spain aut Yang Changbing E.T.S. Ingenieros de Caminos, Canales y Puertos, Universidad de A Coruña, 15192, A Coruña, Spain aut Transport in Porous Media Kluwer Academic Publishers 69/1(2007-08-01), 67-88 0169-3913 69:1<67 2007 69 11242 https://doi.org/10.1007/s11242-006-9065-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11242-006-9065-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Samper-Calvete Javier E.T.S. Ingenieros de Caminos, Canales y Puertos, Universidad de A Coruña, 15192, A Coruña, Spain aut NATIONALLICENCE 700 1- Yang Changbing E.T.S. Ingenieros de Caminos, Canales y Puertos, Universidad de A Coruña, 15192, A Coruña, Spain aut NATIONALLICENCE 773 0- Transport in Porous Media Kluwer Academic Publishers 69/1(2007-08-01), 67-88 0169-3913 69:1<67 2007 69 11242 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer