Comparison of Two Types of Modified Zeolites and the Key Factors for Cd(II) Adsorption Processes in Micropolluted Irrigation Water

Round 1

Reviewer 1 Report

The comments are as follows:

1.  Add the novelty statement in the introduction section.

2. Different types of modification and their effect on zeolite must be included in the introduction to justify the current work. 

3. What about the usability of chitosan-loaded natural zeolite composite? Chitosan may leach into the solution if synthesized without crosslinking or solidification.  

4. Section 2.2.4. and Fig. 2 is not needed. 

5. 2.3. Experimental method: all the conditions must be more clearly written.

6. FTIR needs to be revised why the NH2 peak was observed in natural zeolite and AZ. 

7. Cd(II) removal mechanism must be explored. Justification for each parameter must be added. 

8. Adsorption kinetic must be analyzed. 

9. The language of the article must be revised.

10. Compare this work's Cd(II) removal efficacy with the literature.

11. My suggestion to the authors is to add more batch mode experiments to optimize the pH, equilibrium time etc.   

 

Need improvement. 

Author Response

Response to Reviewer 1 Comments

 

Response 1.  Add the novelty statement in the introduction section.

Thank you very much for your comments. We have added corresponding descriptions regarding the novelty in the introduction.

Response 2. Different types of modification and their effect on zeolite must be included in the introduction to justify the current work. 

Thank you for your comment. We have included relevant content in the introduction to demonstrate the impact of different types of modifications on zeolite and justify the current work.

Response 3. What about the usability of chitosan-loaded natural zeolite composite? Chitosan may leach into the solution if synthesized without crosslinking or solidification.  

Thank you for your comment. The study of the composite material in the paper is in the experimental stage, and the experimental results indicate that it can reduce the adsorption equilibrium time, but it is still far from practical applications. The next step of the research will consider measures such as cross-linking or solidification to address this issue.

Response 4. Section 2.2.4. and Fig. 2 is not needed. 

Thank you for your comment. We have removed the relevant content from the manuscript.

Response 5. 2.3. Experimental method: all the conditions must be more clearly written.

Thank you for your comment. We have made the necessary modifications in the relevant section.

Response 6. FTIR needs to be revised why the NH2 peak was observed in natural zeolite and AZ. 

In natural zeolite and activated zeolite, absorption peaks are observed, but the peak intensity is lower. Chitosan-loaded zeolite shows a higher peak intensity.

Response 7. Cd(II) removal mechanism must be explored. Justification for each parameter must be added. 

Thank you for your comment. We have made the necessary modifications in the relevant section.

Response 8. Adsorption kinetic must be analyzed. 

Thank you for your comment. We have added the relevant content on adsorption kinetics.

Response 9. The language of the article must be revised.

Thank you for your comment. We have revised the language in the manuscript.

Response 10. Compare this work's Cd(II) removal efficacy with the literature.

Thank you for your comment. We have included a comparison of the removal efficiency in Section 3.2.2 of the manuscript.

Response 11. My suggestion to the authors is to add more batch mode experiments to optimize the pH, equilibrium time etc.   

Thank you for your suggestion. We will conduct more batch mode experiments in future research to optimize pH, equilibrium time, etc.

 

 

Reviewer 2 Report

Current manuscript compares two types of modified zeolites and the key factors for Cd(Ⅱ) adsorption processes in micro polluted irrigation water. The FTIR, XRD, and SEM have been employed for characterization of samples.  I think it is interesting and it can be published after addressing my concerns in this regard.

1. Abstract must be rephrased. Please enrich with quantitative data.

2. Introduction: In the first paragraph of introduction "China is ....". Please mention "world" not one case such china. Because the obtained data of manuscript can be used as comprehensive.

3. The following references for improving the introduction can be useful.

https://doi.org/10.1016/j.molliq.2019.111789; https://doi.org/10.1038/s41598-022-08668-1

4. Section "2.1. Experimental materials" is very confusing. Please rewrite it.

5. In the Experimental section, authors mentioned to "The chitosan solution of 1% concentration was taken in a 100 mL beaker, and the

mass ratio of chitosan to natural zeolite was 0.05". 

How did you find the optimal values for composite synthesis? 

6. Figures 1 and 3. are not Figures, please change to Scheme

7. Figure 4. The SEM of natural zeolite. They are very low. 8. Please provide high resolution SEM images with a clear scale bar.

9.One of the important analyses for adsorbents is BET. Please provide the BET of samples for showing the specific surface area of them.

 Minor editing of English language required

Author Response

Thank you very much for your comment. 

Author Response File: Author Response.pdf

Reviewer 3 Report

In this work, Zeolites were used for the treatment of the micro-polluted irrigation water quality simulated by low concentration of Cd(Ⅱ) contamination. My comments are as follows,

1.      Compared with montmorillonite and kaolinite, what are the advantages of Zeolites?

2.      The main components of zeo-lite were SiO2 68%~71%, Al2O3 13%~14%, Fe2O3 1%~1.8%. How did the author obtain this data? Please provide the testing process.

3.      What is the most important factor affecting the adsorption effect in this project?

4.      How stable is the material prepared by the author?

5.      The flowing adsorbents for contaminants should be compared in this work (10.1016/j.jhazmat.2020.123810, 10.1016/j.seppur.2021.119638).

6.      There are grammatical errors in the manuscript, and the author should improve again.

There are grammatical errors in the manuscript, and the author should improve again.

Author Response

Response to Reviewer 3 Comments

 

Response 1.  Compared with montmorillonite and kaolinite, what are the advantages of Zeolites?

Thank you very much for your comment and correction. We have added relevant content regarding the advantages of zeolite.

Response 2.      The main components of zeo-lite were SiO2 68%~71%, Al2O3 13%~14%, Fe2O3 1%~1.8%. How did the author obtain this data? Please provide the testing process.

Thank you for your comment. The main components of clinoptilolite zeolite were provided by the manufacturer.

Response 3.      What is the most important factor affecting the adsorption effect in this project?

This paper focuses on finding the optimal adsorption conditions from an application perspective. The important factors affecting adsorption efficiency can be found in the doctoral thesis (Study on Cd(II) adsorption mechanism from Micro-polluted water for irrigation by modified zeolites).

Response 4.      How stable is the material prepared by the author?

Thank you for your comment. Activated zeolite exhibits good stability. However, in the case of chitosan-loaded natural zeolite, there may be leaching of chitosan into the solution. In the next step of the research, measures such as cross-linking or solidification will be considered to prevent this issue.

Response 5.      The flowing adsorbents for contaminants should be compared in this work (10.1016/j.jhazmat.2020.123810, 10.1016/j.seppur.2021.119638).

Thank you for your comment. The relevant content has been added to the manuscript.

Response 6.      There are grammatical errors in the manuscript, and the author should improve again.

Thank you for your comment. We have corrected the grammar issues in the manuscript.

 

Round 2

Reviewer 1 Report

Acceptable 

Reviewer 2 Report

It can be published in the current form.

Reviewer 3 Report

Accept in present form.