Mathematical modeling of polymer-induced flocculation by charge neutralization

Runkana, Venkataramana ; Somasundaran, P. ; Kapur, P. C. (2004) Mathematical modeling of polymer-induced flocculation by charge neutralization Journal of Colloid and Interface Science, 270 (2). pp. 347-358. ISSN 0021-9797

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S00219...

Related URL: http://dx.doi.org/10.1016/j.jcis.2003.08.076

Abstract

A detailed mathematical model for flocculation of colloidal suspensions in presence of salts and polymers is described and validated. In former case, the classical DLVO theory, which accounts for relevant variables such as pH and salt concentration, is incorporated into a geometrically sectioned discrete population balance model. For processes involving polymers, flocculation via simple charge neutralization is modeled using a modified DLVO theory in which the effect of adsorbed polymer layers on van der Waals attraction is included. The fractal dimension of aggregates is obtained by dynamic scaling of experimental data for time evolution of mean aggregate size. The particle surface potential is assumed to be approximately equal to the zeta potential. The model predictions are in close agreement with experimental results for flocculation of colloidal hematite suspensions in the presence of KCl and polyacrylic acid at different concentrations. In particular, given values of model parameters, e.g., Hamaker constant, fractal dimension, surface potential, and thickness of adsorbed polymer layer, the model can realistically describe the kinetics of flocculation by a simple charge neutralization mechanism and track the evolution of floc size distribution. Representative examples of sensitivity of the flocculation model to perturbations in surface potential and fractal dimension and to modification in the DLVO theory for polymer-coated particles are included.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Flocculation Kinetics; Colloidal Suspensions; Modeling; Population Balances; Surface Forces; Polymers; Charge Neutralization; Fractal Aggregates; Dynamic Scaling
ID Code:17652
Deposited On:16 Nov 2010 12:55
Last Modified:04 Jun 2011 07:20

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