TY  - JOUR
AU  - Lönartz, Mara I.
AU  - Yang, Yuankai
AU  - Deissmann, Guido
AU  - Bosbach, Dirk
AU  - Poonoosamy, Jenna
TI  - Capturing the Dynamic Processes of Porosity Clogging
JO  - Water resources research
VL  - 59
IS  - 11
SN  - 0043-1397
CY  - [New York]
PB  - Wiley
M1  - FZJ-2023-05508
SP  - e2023WR034722
PY  - 2023
AB  - Understanding geochemical processes and their impact onmacroscopic transport properties of porous media is essential fordescribing the long-term evolution of various subsurfacesystems. Chemical and thermal gradients promote mineralprecipitation reactions in porous media, resulting in a reductionof porosity and potentially clogging transport pathways ofsolutes. Commonly applied porosity-diffusivity relationships incontinuum-scale reactive transport modelling based on Archie’slaw and extended versions thereof describe the case of cloggingas a final state, setting the effective diffusivity to a negligible lowvalue. However, recent experiments and pore-scale modellinginvestigations demonstrated the limitations of empirical laws inpredicting effective transport properties in response to aprecipitation induced porosity reduction and pore clogging,suggesting a non-negligible inherent diffusivity of newly-formedprecipitates. To verify this hypothesis, we developed amicrofluidic reactor design that combines time-lapse opticalmicroscopy and confocal Raman spectroscopy, providing realtimeinsights into mineral precipitation induced porosity cloggingunder purely diffusive transport conditions, using theprecipitation of celestine (SrSO4) as a model system (Figure 1a).As the pore network became clogged, isotopic tracer diffusionexperiments were conducted and monitored by Ramanspectroscopy to visualize the transport of deuterium through theevolving microporosity of the precipitates, demonstrating thenon-final state of clogging (Figure 1b). The evolution of theporosity-diffusivity relation in response to precipitation reactionsshows an increasingly deviating behavior to Archie’s law. Theapplication of an extended power law improved the descriptionof the evolving porosity-diffusivity relation, but still neglectedpost-clogging features. Currently, we develop microfluidicsetups to answer the question how clogging-related processesdepend on initial pore geometries. The combination ofmicrofluidic experiments and pore-scale modelling opens newpossibilities to identify and validate relevant pore-scaleprocesses, providing data for upscaling approaches and to derivekey relationships for continuum-scale reactive transportsimulations.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:001106027500001
DO  - DOI:10.1029/2023WR034722
UR  - https://juser.fz-juelich.de/record/1019573
ER  -