A Simple Method to Determine Critical Coagulation Concentration from Electrophoretic Mobility

Round 1

Reviewer 1 Report

The manuscript discusses on the critical coagulation concertation (CCC) of various charge stabilized colloidal dispersions on the basis of DLVO theory with Debye-Hückel approximation. I think this paper is excellent and interesting to colloid science community. Therefore, the manuscript is acceptable for publication after minor revision related to the points below.

 

Minor points.

 CCC is usually discussed with Schulze-Hardy rule. Isn’t it necessary to touch Schulze-Hardy rule?

Page 2, line 12: “must” would be “most” ?

Page 3, line 1: “double-layer” would be “diffuse-layer”

Page 3, the below Eq. (8): “there” would be “their”

The caption of Figure 1: It is better to add “(TNS)” after titania nanosheets.

Author Response

Our replies are in the attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

In this paper Marco Galli, Szilárd Sáringer, István Szilágyi and Gregor Trefalt report on a new method based on the DLVO theory to predict Critical Coagulation Concentration (CCC) of colloids in presence of aggregating agent.

The paper is well structured, very clear, and touches on a fundamentally important aspect of colloidal science. The reader is guided through the approach taken in a very lean manner.

Overall, the outcome the paper seems reasonable, and is straighten by the comparison with experimental data. One can particularly enjoy that the code is developed in python and posted on Github for the community. I am sure this will raise a substantial attention and appreciation.

 

Throughout the reading, I have noticed some points that the authors may want to correct prior to publication:

• It would be valuable to define the limitation of the model in the introduction. Given that it relies on DLVO theory, certain type of particles will certainly not be well described (highly hydroxylated system, eg. Silica nanoparticles). In essence this is not a problem and the authors even discuss that, but it takes to reach the end of the paper to see that. Another point would be to mention the effect of the shape of the particle, even briefly. This again is pointed out in the end of the article to explain some deviation and make perfect sense. But I assume that some reader would like to see the conditions of valid posed from the beginning.
• Line 68: typo in “ionic”
• Line 80: can the authors suggest such a function? One understand that it has no physical meaning and it is only for the purpose of fitting data, but I guess beginners in that field would appreciate that.
• Line 117: “For each systems CCCs induced by different ions are shown.” Should be rephrased. “For each systems CCCs resulting from the aggregation induced by different ions are shown.” Or something like that.
• Line 144: “This results … DLVO model”. I guess the authors refer to the concept of percolation which can be especially pronounced for non spherical particles (lower percolation threshold). Maybe this could be clarified.

Author Response

Our replies are in the attached file.

Author Response File: Author Response.pdf