Hydrodynamic and Chemical Factors in Clogging by Montmorillonite in Porous Media

Clogging by colloid deposits is important in water treatment
filters, groundwater aquifers, and petroleum reservoirs.
The complexity of colloid deposition and deposit morphology
preclude models based on first principles, so this study
extends an empirical approach to quantify clogging using
a simple, one-parameter model. Experiments were
conducted with destabilized suspensions of sodium- and
calcium-montmorillonite to quantify the hydrodynamic and
chemical factors important in clogging. Greater clogging
is observed at slower fluid velocity, consistent with previous
investigations. However, calcium-montmorillonite causes
1 order of magnitude less clogging per mass of deposited
particles compared to sodium-montmorillonite or a
previously published summary of clogging in model granular
media. Steady-state conditions, in which the permeability
and the quantity of deposited material are both constant,
were not observed, even though the experimental conditions
were optimized for that purpose. These results indicate
that hydrodynamic aspects of clogging by these natural
materials are consistent with those of simplified model
systems, and they demonstrate significant chemical effects
on clogging for fully destabilized montmorillonite clay.