Liquid phase migration

Liquid phase migration and retention — NAPL held suspended by the water table or capillary fringe or perched above low permeability zones (water wet soil) in the unsaturated zone. 

Mascia S. Patel MJ, Rough SL. ct al. Liquid phase migration in the extrusion and squeezing of microcrystalline cellulose pa.stes. Eur J Pharm Sci 2006 29 22-34. 

Thus the key to successful processing lies in the formulation of the material by having additives, commonly a clay and water, present in amounts that render the mass mouldable at a low applied stress. On its own, this argues for high liquid content. However, a greater liquid content causes an increase in the rate of movement of the liquid. The benefits are then reversed unacceptable levels of liquid phase migration have to be avoided. 

Hirata H, Aoki T, Nakajima K (2012) Liquid phase migration effects on the evaporative and condensational dissipation of phosphoric acid in phosphoric acid fuel cell. J Power Sources 199 110-116... 

When reactants are distributed between several phases, migration between phases ordinarily will occur with gas/liquid, from the gas to the liquid] with fluid/sohd, from the fluid to the solid between hquids, possibly both ways because reactions can occur in either or both phases. The case of interest is at steady state, where the rate of mass transfer equals the rate of reaction in the destined phase. Take a hyperbohc rate equation for the reaction on a surface. Then,... 

In liquid-phase applications, transfer of the adsorbate from the bulk solution to the carbon particle must proceed through two stages first, via transfer of the adsorbate from the bulk liquid to the surface of the carbon particle, and second, by migration... 

NAPL will migrate from the liquid phase into the vapor phase until the vapor pressure is reached for that liquid. NAPL will move from the liquid phase into the water phase until the solubility is reached. Also, NAPL will move from the gas phase into any water that is not saturated with respect to that NAPL. Because hydraulic conductivities can be so low under highly unsaturated conditions, the gas phase may move much more rapidly than either of the liquid phases, and NAPLs can be transported to wetter zones where the NAPL can then move from the gas phase to a previously uncontaminated water phase. To understand and model these multiphase systems, the characteristic behavior and the diffusion coefficients for each phase must be known for each sediment or type of porous media, leading to an incredible amount of information, much of which is at present lacking. 

Under most circumstances microorganisms are attached to solid soil particles and await the arrival of water, nutrients, and electron acceptors. When the biomass is above the water table, the dependence is upon migration of nutrients and diffusion of oxygen downward (or upward via capillary action). Bacterial colonies that develop below the saturated zone are dependent upon liquid phases for the delivery of necessary growth media. 

Figure 12-10 Sketches of reactant concentration Ca around a spherical bubble or drop that reacts after migrating from ftie gas phase into the liquid phase in bubble column and spray tower reactors.

Figure 12-15 Sketch of concentration profiles between a spherical bubble and a solid spherical catalyst particle in a continuous liquid phase (upper) in a gas-liquid sluny reactor or between a bubble and a planar solid wall (lower) in a catalytic w bubble reactor, It is assmned that a reactant A must migrate from the bubble, tirough the drop, md to tiie solid catdyst smface to react. Concentration variations may occur because of mass transfer limitations around both bubble and solid phases.

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