Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 10096–10101 |
| Number of pages | 6 |
| Journal | Environmental Science and Technology |
| Volume | 45 |
| Issue number | 23 |
| DOIs | |
| Publication status | Published - 2011 |
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Correlation equation for predicting attachment efficiency (α) of organic matter-colloid complexes in unsaturated porous media. / Morales, Veronica L.; Sang, Wenjng; Fuka, Daniel R.; Lion, Leonard W.; Gao, Bin; Steenhuis, Tammo S.
In: Environmental Science and Technology, Vol. 45, No. 23, 2011, p. 10096–10101.Research output: Contribution to journal › Article
TY - JOUR
T1 - Correlation equation for predicting attachment efficiency (α) of organic matter-colloid complexes in unsaturated porous media
AU - Morales, Veronica L.
AU - Sang, Wenjng
AU - Fuka, Daniel R.
AU - Lion, Leonard W.
AU - Gao, Bin
AU - Steenhuis, Tammo S.
PY - 2011
Y1 - 2011
N2 - Naturally occurring polymers such as organic matter have been known to inhibit aggregation and promote mobility of suspensions in soil environments by imparting steric stability. This increase in mobility can significantly reduce the water filtering capacity of soils, thus jeopardizing a primary function of the vadose zone. Improvements to classic filtration theory have been made to account for the known decrease in attachment efficiency of electrostatically stabilized particles, and more recently, of sterically stabilized particles traveling through simple and saturated porous media. In the absence of an established unsaturated transport expression, and in the absence of applicable theoretical approaches for suspensions with asymmetric and nonindifferent electrolytes, this study presents an empirical correlation to predict attachment efficiency (α) for electrosterically stabilized suspensions in unsaturated systems in the presence of nonideal electrolytes. We show that existing models fall short in estimating polymer-coated colloid deposition in unsaturated media. This deficiency is expected given that the models were developed for saturated conditions where the mechanisms controlling colloid deposition are significantly different. A new correlation is derived from unsaturated transport data and direct characterization of microspheres coated with natural organic matter over a range of pH and CaCl2 concentrations. The improvements to existing transport models include the following: adjustment for a restricted liquid-phase in the medium, development of a quantitative term to account for unsaturated transport phenomena, and adjustments in the relative contribution of steric stability parameters based on direct measurements of the adsorbed polymer layer characteristics. Differences in model formulation for correlations designed for saturated systems and the newly proposed correlation for unsaturated systems are discussed, and the performance of the new model against a comprehensive set of experimental observations is evaluated.
AB - Naturally occurring polymers such as organic matter have been known to inhibit aggregation and promote mobility of suspensions in soil environments by imparting steric stability. This increase in mobility can significantly reduce the water filtering capacity of soils, thus jeopardizing a primary function of the vadose zone. Improvements to classic filtration theory have been made to account for the known decrease in attachment efficiency of electrostatically stabilized particles, and more recently, of sterically stabilized particles traveling through simple and saturated porous media. In the absence of an established unsaturated transport expression, and in the absence of applicable theoretical approaches for suspensions with asymmetric and nonindifferent electrolytes, this study presents an empirical correlation to predict attachment efficiency (α) for electrosterically stabilized suspensions in unsaturated systems in the presence of nonideal electrolytes. We show that existing models fall short in estimating polymer-coated colloid deposition in unsaturated media. This deficiency is expected given that the models were developed for saturated conditions where the mechanisms controlling colloid deposition are significantly different. A new correlation is derived from unsaturated transport data and direct characterization of microspheres coated with natural organic matter over a range of pH and CaCl2 concentrations. The improvements to existing transport models include the following: adjustment for a restricted liquid-phase in the medium, development of a quantitative term to account for unsaturated transport phenomena, and adjustments in the relative contribution of steric stability parameters based on direct measurements of the adsorbed polymer layer characteristics. Differences in model formulation for correlations designed for saturated systems and the newly proposed correlation for unsaturated systems are discussed, and the performance of the new model against a comprehensive set of experimental observations is evaluated.
U2 - 10.1021/es2023829
DO - 10.1021/es2023829
M3 - Article
VL - 45
SP - 10096
EP - 10101
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 23
ER -