The Effect of Cu (II) on Swelling and Shrinkage Characteristics of Sodium Bentonite in Landfills
Round 1
Reviewer 1 Report
Topic of the presented manuscript fits to the scope of this journal. The presented manuscript interprets lot of interesting experimental data.
On the other hand, the data are often confused and some figures are very difficult to understand and the description of these figures in text will not help.
There are some inaccurate or strange formulation in the text,
e.g.
line 43 – Once those heavy copper intruded… just copper is enough, copper cannot be other than heavy
line 114 The added water in the solution preparation was deionized water.
line 229 The existence of Cu will cause…. probably not existence but presence
line 493 Title: Erosion mechanism of heavy metal Cu (II) … in fact it is Mechanism of bentonite erosion caused by Cu(II)
There are also lot of typing errors, e.g.:
line 46 erosion.Since… (spacebar is missing)
line 67 2008).The swelling… (spacebar is missing)
line 68 ity Usually, the …. (punctuation is missing)
line 100 a temperature of 105 degrees for 24h. (degrees mean °C)
In all tables and figures where is concentration of copper is C (g/l) but correct is Cu (g/l) e.g. table 2, figure 3, table 3.
line 190 The instrument used in XRD test was TTR III produced by Japanese Physiology. It seems that Japanese physiology is producer of XRD instruments, I think this instrument is from Rigaku. Same state is with XRF instrument.
In whole manuscript there are no information about statistics of experiments. Were all experiment done in triplicate or was done single experiment? It is important, especially for interpretation of figures 8 where are differences between points very small and I guess sometimes are differences in the range of uncertainty.
In figures are Stages (1,2,3) but in text is no explanation what does it mean stage 1, stage 2 and stage 3.
Figure 4 Interpretation of both figures (a,b) in the text is very poor, my recommendation to authors is extend the description and the results resulting from this figure.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript ,,The Effect of Cu (II) on Swelling and Shrinkage Characteristics of Sodium Bentonite in Landfills,, address an interesting environmental issue. However, before publication can be considered, a major review needs to be carried out and some important questions has been answered.
My advice, comments and recommendations are listed below.
Please be sure that your manuscript thoroughly establishes how this work is fundamentally novel. Specific comparisons should be made to previously published materials that have a similar purpose. Please present a strong case for how this work is a major advance. This needs to be done in the manuscript itself, not just in the response to review comments. This is a very important point in terms of which I will further consider the manuscript.
Please be sure that your abstract and your Conclusions section not only summarize the key findings of your work but also explain the specific ways in which this work fundamentally advances the field relative to prior literature.
Line 17, Abstract: ,,Cu+2,, change to ,,Cu2+,,
Line 31: The word montmorillonite could be added to the keywords.
The significance of this study should be more emphasize in the introduction.
Take a look at this paper, it might help you. https://www.mdpi.com/2071-1050/10/7/2489
Line 42, lead (Pb) and Cu (copper): Pay attention to this important paper, which dealt with this in detail. Authors are encouraged to add it to this place to improve the introduction. https://www.sciencedirect.com/science/article/abs/pii/S0304389420316149
Line 51: It would be appropriate to start with where bentonites (montmorillonite) are still used in other areas and then go through that it is also important for environmental studies in the adsorption of heavy metals.
Line 55, unequal cation substitution.: This statement is confirmed by this important document. Therefore, it is necessary to add it here as a reference to improve the introduction. https://www.sciencedirect.com/science/article/abs/pii/S0169131719301413
Line 74: And what about a strongly alkaline pH higher than 9?
Line 96: Indicate the structural formula as well as the chemical composition of the relevant oxides of sodium bentonite.
Line 100: ,,degrees,, change to ,,°C,, Use SI units.
Line 110: There was a formatting error. Please fix it.
Line 111: ,,Cu+2,, change to ,,Cu2+,, pay attention to it throughout the text.
Line 116: Pay attention to the correct notation of Si units throughout the manuscript.
Line 193: And what about diffractions at higher angles? Important hkl diffractions may occur there.
Line 237: Hydrophilicity can be verified by FTIR and detection of OH groups from water. It is a pity that this manuscript does not contain FTIR results.
Line 286: Check that the equations are written correctly with explanations throughout the manuscript.
Line 371: There are formatting issues throughout the manuscript, please check it.
Line 413: As I mentioned above, it would be interesting to see a diffractogram in the range up to 70 ° 2 theta.
Line 447: No significant differences are visible in Figure 8a. How do you explain that?
Line 490: This reaction should be written in a better proposal.
Line 494: ,,Al3+,, change to ,,Al3+,,
Line 539: Indicate the possible risks of such research. Add your recommendations for future research.
Line 562: Make sure the references are added correctly according to the journal's instructions.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
All my previous remarks were satisfactory incorporated to the manuscript.
In case of concentration symbol – most common is used c and not capital letter C.
My recommendation it use c and e.g. in table 3 it is not evident about the concentration of what it is. It should be stated that it is the concentration of cooper.
Table 3 - Please adjust the number of decimal places, in table 4 it is correct
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
The manuscript ,,The Effect of Cu (II) on Swelling and Shrinkage Characteristics of Sodium Bentonite in Landfills,, has been significantly improved. The authors responded to all comments and improved the quality of the manuscript.
I only noticed some errors in the references section.
Line 651: Reference number 7: Authors' names should be written as follows: Wang, Q.; Shaheen, S.M.; Jiang, Y.; Li, R.; Slaný, M.; Abdelrahman, H.; Kwon, E.; Bolan, N.; Rinklebe, J.; Zhang, Z.
Line 680: Reference number 20: Authors' names should be written as follows: Slaný, M.; Jankovič, L.; Madejová, J.
Please fix it.
After these minor adjustments, the manuscript can be accepted.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
