Variability in crystal surface reactivity: A critical constraint for reactive transport modeling

Reactive transport modeling of fluid-solid interactions relies on (i) contrasts in fluid flow velocity and (ii) variability of surface reactivity. The first point is based on data from, e.g., PET and µCT techniques. The second point, however, is usually addressed by simple kinetic data only. Thus, it neglects information about the intrinsic variability of crystal surface reactivity that often results in a rate range of 2-3 orders of magnitude (1). Such variability is however an important constraint for the evolution of surface roughness and porosity pattern in crystalline matter (2). Here, we highlight important sources of the intrinsic variability of crystal surface reactivity and their impact on surface reaction rates. Rate maps (3) and rate spectra (4) provide critical information about the spatial and temporal variability of surface reactivity that is required to predict the evolution of porosity pattern in crystalline matter (5).

1. Luttge A, Arvidson RS, & Fischer C (2013) A Stochastic Treatment of Crystal Dissolution Kinetics. Elements 9(3):183-188.
2. Fischer C, Kurganskaya I, Schäfer T, & Luttge A (2014) Variability of Crystal Surface Reactivity: What do we know? (Review Article). Applied Geochemistry 43:132-157.
3. Fischer C & Luttge A (2017) Beyond the conventional understanding of water–rock reactivity. Earth and Planetary Science Letters 457:100-105.
4. Fischer C, Arvidson RS, & Luttge A (2012) How predictable are dissolution rates of crystalline material? Geochimica et Cosmochimica Acta 98:177-185.
5. Michaelis M, Fischer C, Colombi Ciacchi L, & Luttge A (2017) Variability of Zinc Oxide Dissolution Rates. Environmental Science & Technology 51(8):4297-4305.