.. raw:: latex \clearpage 1D Surface complexation ======================= Overview and Capabilities tested -------------------------------- This test example performs the simulation of :math:`\ce{Zn^{2+}}` surface complexation on weak and strong iron hydroxide sites in a 1D flow domain. * 1D flow * 1D advective transport * Geochemical reactions * Aqueous complexation reactions (equilibrium) * Surface complexation reactions (equilibrium) For details on this test, see :ref:`about_surface_complexation`. Background ---------- Introduction ------------ Description of surface complexation... The simulation is run to 50 years. Model ----- Flow and transport ~~~~~~~~~~~~~~~~~~ See the :doc:`../tracer_1d/amanzi_u-1d-tracer` example. Aqueous complexation ~~~~~~~~~~~~~~~~~~~~ Five equilibrium reactions are considered in aqueous phase that include the aqueous speciation of :math:`\ce{Zn^{2+}}` (by convention, secondary species are given in the left hand side, while primary species are in the right hand side): * :math:`\ce{OH^- <=> H_2O - H^+}`, :math:`\; log(K)=13.9951` * :math:`\ce{Zn(OH)_{2(aq)} <=> 2 H_2O - 2 H^+ + Zn^{2+}}`, :math:`\; log(K)=17.3282` * :math:`\ce{Zn(OH)_3^- <=> 3 H_2O - 3 H^+ + Zn^{2+}}`, :math:`\; log(K)=28.8369` * :math:`\ce{Zn(OH)_4^{2-} <=> 4 H_2O - 4 H^+ + Zn^{2+}}`, :math:`\; log(K)=41.6052` * :math:`\ce{ZnOH^+ = H_2O -1 H^+ + 1 Zn^{2+}}`, :math:`\; log(K)=8.96` Surface complexation ~~~~~~~~~~~~~~~~~~~~ Two distinct iron hydroxide (:math:`\ce{FeOH}`) surface sites are available for sorption of :math:`\ce{Zn^{2+}}`: weak :math:`\ce{({>}FeOH_{w})}` and strong :math:`\ce{({>}FeOH_{s})}`. Surface site concentrations for :math:`\ce{>FeOH_{w}}` and :math:`\ce{>FeOH_{s}}` are defined in 'Material Properties'. No explicit definition of the mineral phase on which :math:`\ce{Zn^{2+}}` is required. In total, six surface complexation reactions are considered: * :math:`\ce{{>}FeOH_{2w}^+ <=> {>}FeOH_{w} + H^+}`, :math:`\; log(K)=-7.18` * :math:`\ce{{>}FeO^{-}_{w} <=> {>}FeOH_{w} - H^+}`, :math:`\; log(K)=8.82` * :math:`\ce{{>}FeOHZn^{+}_{w} <=> {>}FeOH_{w} - H^+ + Zn^{2+}}`, :math:`\; log(K)=2.32` * :math:`\ce{{>}FeOH_{2s}^+ <=> {>}FeOH_{s} + H^+}`, :math:`\; log(K)=-7.18` * :math:`\ce{{>}FeO^{-}_{s} <=> {>}FeOH_{s} - H^+}`, :math:`\; log(K)=8.82` * :math:`\ce{{>}FeOHZn^{+}_{s} <=> {>}FeOH_{s} - H^+}` :math:`\; log(K)=-0.66` Problem Specification --------------------- Flow and transport ~~~~~~~~~~~~~~~~~~ See the :doc:`../tracer_1d/amanzi_u-1d-tracer` example. Geochemistry ~~~~~~~~~~~~ To do. Results and Comparison ---------------------- Expected results ~~~~~~~~~~~~~~~~ These are the expected results. Simulation results ~~~~~~~~~~~~~~~~~~ .. plot:: benchmarking/chemistry/surface_complexation_1d/surface_complexation_1d.py .. _about_surface_complexation: About ----- * Benchmark simulator: PFlotran * Files: * Amanzi input file: amanzi-u-1d-surface-complexation.xml * Benchmark simulator input file: 1d-surface-complexation.in * Location: amanzi/examples/examples/phase2/chemistry/1d-surface-complexation * Author: B. Andre, G. Hammond * Testing and Documentation: S. Molins * Last tested on Aug 31 2013