Evaporation from Saline Porous Media with the Associated Salt Precipitation Patterns and Dynamics.

The excess accumulation of salt in soil is a global problem and is one of the most widespread soil degradation processes in the world which is of major concern in soil salinity, terrestrial ecosystem functioning, and water management among many others. Accumulation of salt in soil adversely influences the plant growth, vegetation and crop production. Thus it is important to understand the parameters and mechanisms controlling salt transport and precipitation patterns in porous media. During evaporation from saline porous media, the capillary induced liquid flow transports the solute towards the evaporation surface while diffusive transport tends to spread the salt homogenously in the porous medium. As water evaporates, salt concentration in the pore space increases continually until it exceeds the solubility limit when it precipitates. This process is influenced by various parameters such as transport properties of porous media, nature of salt, and atmospheric conditions. We have conducted a comprehensive series of theoretical and experimental analysis to investigate the effects of several parameters on the dynamics of salt transport and precipitation patterns in drying saline porous media at pore- and macro-scale.  Our results revealed the effects of atmospheric conditions, particle size distribution, pore shape and geometry as well as salt concentration on the dynamics of salt precipitation in porous media and provided us with new insights regarding the physics of salt precipitation and its complex dynamics in drying porous media.