ERI: Impact of pore-scale heterogeneity on precipitation and transport in porous media

The precipitation of solutes in porous structures and subsurface systems can cause a cascade of unexpected issues, including clogging of pores, as in the salt precipitation upon injection of CO2 in a brine aquifer. This award aims to investigate the precipitation of water-soluble polymers in porous media and the impact of medium heterogeneity on precipitation and transport across the medium. Soft lithography will be used to fabricate two-dimensional porous environments with different heterogeneities. Using optical microscopy, the changes in network structure and flow distribution will be monitored upon injection of antisolvent to precipitate the polymer. These studies will reveal how precipitation and clogging regulate the flow distribution in the network of connected pores. The broader impacts of this award include training graduate students and undergraduates to study these timely problems and to develop a quantitative understanding of transport in porous media. It will also enable new demonstrations to inspire and engage K-12 students in the Science lessons delivered at the local Boys and Girls Club. This award will develop new experimental techniques and improved mathematical models to generate a fundamental understanding of reactive transport in porous media. The goal is to investigate how medium heterogeneity and dynamic network changes due to precipitation impact long-term advection and reaction processes in porous media. The following systematic aims are considered: 1) the study of the role of local medium heterogeneity in the transition between advection-dominated and reaction-dominated regimes, and 2) the self-limiting transport of solute due to precipitation. The correlation between advection and precipitation rates with the time scale of the response of the system to local changes will be used to predict clogging due to reactive transport. The results will provide foundational models of reactive transport based on bulk transport properties accessible in industrial operations to maintain percolation and avoid clogging. More broadly, this award will advance the understanding of self-regulating growth at the interface of two miscible fluids in a confined and heterogeneous environment. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.