CVEN 6414 Aquatic Surfaces and Particles

Problem Set 7: Colloid Deposition Kinetics

 

Use the data collected by Kretzschmar et al. (1997), determine the deposition rate coefficients (k) and collision efficiencies (a) for the sulfate latex colloids in the columns filled with soda-lime glass beads at the three different ionic strengths shown for the step and pulse injections (Figure 2a and 2b).

For the step injections, the deposition rate coefficient can be determined with Eqn. 2, 3, and 4.

The pulse injection deposition rate coefficient can be calculated with Eqn. 5 -- this equation requires integration of the area under the colloid breakthrough curves in Figure 2b.

The value of the "fast" (a = 1) deposition rate coefficient kfast  (Eqn. 6) can be calculated using the katt equation given in Lecture 11 (May 25) (katt = k in Kretzschmar et al., 2000) and a single collector efficiency (h) calculated using the Tufenkji and Elimelech (2004) correlation equations.

Your results should include six values of k and a -- three ionic strengths for the step injections and three ionic strengths for the pulse injections.  Present your results in a graph like Figure 2c.

Give a brief (< 100 words) explanation of the trend in the deposition rate coefficient and collision efficiency with increasing ionic strength.

 

Last updated on May 28, 2007 by Joe Ryan