Experimental Investigation of Salt Precipitation in a Free-Flow/Porous-Media Microfluidic System
Shujie Guo, Wenqian Zhang, and Bo Guo
Department of Hydrology and Atmospheric Sciences
University of Arizona
Salt precipitation is an important process in many environmental and technical applications such as soil salinization and precipitation in building material. Driven by intense evaporation, dissolved salts migrate with water toward the surface, where they accumulate and precipitate upon exceeding solubility limits. This process contributes to soil degradation, reduced plant growth, and significant economic losses. A fundamental understanding of the mechanisms governing salt precipitation in porous media is essential for developing effective mitigation strategies in agriculture and environmental management.
While mathematical models at different scales have been developed, persistent discrepancies between simulations and experimental observations indicate critical gaps in current knowledge. Microfluidic experiments conducted under well-controlled conditions with high-resolution visualization offer a powerful approach to elucidating the key processes governing salt precipitation. We will report preliminary experiments in a free-flow/porous-media-flow microfluidic system. The specific objectives are: (1) to develop a microfluidic platform that enables the systematic investigation of evaporation and salt precipitation, and (2) to observe and quantify these processes in free-flow/porous-media micromodels. The experimental data will serve as a benchmark for refining and validating pore-network models for simulating evaporation and salt precipitation in such systems.