Polymer–Zeolite Composites: Synthesis, Characterization and Application

Round 1

Reviewer 1 Report

Review for colloids-2756360-v1

My review is centered around a scanned pdf of the manuscript that includes both linguistic suggestions and comments/question marks. Question marks will mark sections/sentences where I had trouble understanding the meaning/context. I would recommend revision of those sections to make them clearer.

The detailed comments below pertain to numbered items in that manuscript (#i) to which I will refer in order of appearance.

#1 what are those properties? It might be so many things that I think it should be specified.

#2 specify the radionuclides

#2 in line 81: what are mineral salts? Why not specify the chemical compounds? What size in µm does mesh 140 correspond?

#3 can you do this on the second digit? What is the error?

#4 what was the order of addition and why was that order chosen?

#5 is this the concentration of the added solution or the final concentration after addition

#6 does this mean one day equilibration?

#7 what is this separating funnel? Is it a filtering technique? Please explain more.

#8 is this Bq or Bk? Please check. Also give molar concentrations in a second row.

#9 awkward wording. “… were fitted using the software SpectrRelax.” If that is what you want to say. For the fitting give some more details.

#10 do not understand this underlined part, and thus the whole sentence is not intelligible to me.

#11 I know this as the free OH or dangling bond, with hydroxyls that cannot hydrogen bond for some reason

#12 what is the interpacket space??

#13 you could do Rietveldt to get the contributions. Was it attempted?

Figure 3: was there hematite in the XRD pattern?

#14 for a total amount you would need units. Or is it in the formula? Not clear to me.

#15 in the writing the tense switches from past to present and back. Please make it uniform.

#16 could be checked by analysis. Was it done?

#17 please replace the comma “,” by the dot “.” in the numbers. Again as in #3, I am not convinced if the second digit is significant.

#18 I do not understand. Replacing Al3+ by four OH- creates a charge difference of -7, seems odd to me.

#19 state the valences here, probably +2 and +3.

#20 the discussion of the hematite is confusing to me. Is there hematite? If it is in the XRD, it should be mentioned (again) here. If it is not in the XRD, would it be better to say that the Fe(III) is in an environment that is similar to hematite? Actually I would be surprised there is hematite in zeolite, but I am no zeolite specialist…

#21 of course both are related and therefore it is not surprising that they both depend on pH.

#22 saturation plateau is maybe something in an isotherm. In a kinetic experiment it reaches a steady state or an equilibrium state. You typically do not know which if you do not do a desorption experiment. Steady state is safe. And 168 hours would be 7 days…

#23 did you check precipitation effects through speciation calculations? And was carbon dioxide present? Then depending on the pH, there might be carbonate phases present.

#24 did the pH change this much? And in the same way for all systems? Would be surprising to me. In these kinds of systems, I would run a more substantial pH variation from say 4 to 10 to get the adsorption edge.

#24, bottom of page 19: I think there is a lot of characterization of these materials, but something that could be very interesting is missing, namely the charging of the particles. I would propose to do zeta-potential measurements, maybe also in the presence of Cs, Ca, Co (inactive). For the current uptake experiments, the choice of the pH values should be stated. Also it is not clear whether a relevant background matrix solution was chosen, whether it was just e.g. MilliQ water (resistance required) or whether carbon dioxide was excluded. You can form carbonates with Ca and Co I guess and this was not discussed here.

Overall I think the characterization is excessive. At least some of it could be put into SI. The adsorption study is not comprehensive and the conditions are not clear.

So, at present I cannot recommend publication.

included above

Author Response

We express our deep gratitude for the work You have done

Author Response File: Author Response.pdf

Reviewer 2 Report

The work is a huge work on the preparation of zeolite based hybride polymer composites using the in situ polymerization technique in the body of mineral matrix and its intercalated with copper ferrocyanide (CuFC) forms. 

The manuscript is very well conceived and well written in adaquate English language. The main output of the work is clearly described and presented in a optimal form. The manuscript deals deeply with a ever-growing topic of interest. The ‘introduction’ paragraph is centered on the aim of the work, with a broad look at the results in the literature. The 'experimental section' part is fully described with adequate methodologies of analysis for the investigation. The 'results’ and ‘discussion' parts explain all results clearly and step-by-step. The manuscript is readable thanks to the figures and table. The topic of the manuscript is of interest to readers of the Journal.

Few minor comments:

- be careful figure 6 is not cited in the text

- add the following reference very useful for the manuscript: https://doi.org/10.1140/epjp/s13360-023-04491-3

- be careful when fig of Fig with capital letter

Author Response

We express our deep gratitude for the work You have done

Author Response File: Author Response.pdf

Reviewer 3 Report

Notes

Introduction

Some explanations and comments should be added to the introduction.

1. What is the advantage of the developed sorbent compared to the chitosan-zeolite biosorbent of radionuclides studied in the work https://doi.org/10.1039/D2VA00148A?

2. Why was acrylic matrix chosen as the polymer matrix?

3. What determines the need for intercalation of zeolite and bentonite? 4. In the Introduction, it is necessary to note the advantages of polymer sorbents in sorption processes, both in the extraction of metals https://doi.org/10.3390/gels8080492, and in terms of improving the environmental situation https://doi. org/10.1002/app.54838.

Results and its discussion

5. The IR spectra show the Transmittance scale, not the Absorbance scale.

6. How do the authors confirm dealumination of zeolite during in situ polymerization? This should be specified.

7. How do the authors plan to reduce the time of equilibrium sorption of radionuclides?

8. It is necessary to provide spectral data of sorbents loaded with radionuclides to confirm the mechanism of sorption of radionuclides (IR spectroscopy or EDS), evidence of the formation of bonds of cobalt ions with oxygen and nitrogen atoms of the carboxyl and amide groups of the polymer matrix.

Overall, the article is well written and coherent.

Minor editing of English language required

Author Response

We express our deep gratitude for the work You have done

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Review for the revised version:

Table 1: the commas should be changed to dots

Table 2: the composition should also be given in molar concentrations

line 267: interlayer instead of interpacket

Table 3: the commas should be changed to dots

line 322: maybe 76.5 % would be more appropriate

line 345: I think the II before Dealumination is generated by the word processor from the I of Ion exchange. Please adjust.

lines 458 ff: the superscript of 2+ needs to be corrected

line 594: should be steady state

Table 5: pH 7; below the table up to 9.0 

Figure 7: I think the subscripts in the texts in the figures is too small to be readable

In general, the authors need to detail, why they use a given number of digits. I think in terms of percentage the second digit will in many measurements not be significant. Errors need to be discussed as well. 

This is all still missing. 

The units are still mixed up, i.e. "mm/sec" or "mm/s" or "mm/ s" can be found.

Sometimes pH 7 is used and then sometimes pH = 7 is used. sometimes with pH 9.0 and sometimes pH 9. Please homogenize, I would excpect that pH approximately 9 would be the correct statement.

In particular pH 7 is very difficult to keep. 

There is still room for improvement. 

English is quite good.

Author Response

Dear reviewer,  

Thank You for the work you have done.

we send the answers and a revised version of the manuscript taking into account your comments and notes.

Author Response File: Author Response.pdf