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Download fileRelease of Colloids from Primary Minimum Contact under Unfavorable Conditions by Perturbations in Ionic Strength and Flow Rate
journal contribution
posted on 2014-08-19, 00:00 authored by Eddy Pazmino, Jacob Trauscht, William P. JohnsonColloid
release from surfaces in response to ionic strength and
flow perturbations has been mechanistically simulated. However, these
models do not address the mechanism by which colloid attachment occurs,
at least in the presence of bulk colloid–collector repulsion
(unfavorable conditions), which is a prevalent environmental condition.
We test whether a mechanistic model that predicts colloid attachment
under unfavorable conditions also predicts colloid release in response
to reduced ionic strength (IS) and increased fluid velocity (conditions
thought prevalent for mobilization of environmental colloids). The
model trades in mean-field colloid–collector interaction for
discrete representation of surface heterogeneity, which accounts for
a combination of attractive and repulsive interactions simultaneously,
and results in an attached colloid population (in primary minimum
contact with the surface) having a distribution of strengths of attraction.
The model moderates equilibrium separation distance by inclusion of
steric interactions. By using the same model parameters to quantitatively
predict attachment under unfavorable conditions, simulated release
of colloids (for all three sizes) from primary minimum attachment
in response to perturbations qualitatively matched experimental results,
demonstrating that both attachment and detachment were mechanistically
simulated.