Effective Adsorptive Removal of Coomassie Violet Dye from Aqueous Solutions Using Green Synthesized Zinc Hydroxide Nanoparticles Prepared from Calotropis gigantea Leaf Extract

Round 1

Reviewer 1 Report

The manuscript entitled “Green Synthesis of Zinc Hydroxide Nanoparticles Using Calot- 2 ropis gigantea Leaf Extract and its Application in Removal of 3
Toxic Coomassie Violet Dye from Aqueous Solutions: Optimi- 4 zation, Isotherm, Thermodynamic, and Kinetic Investigation” can be considered for publication in Chemengineering Journal, after a minor revision.

-          the title is too long, please change it

-          the summary is long, please add only the necessary information

-          Introduction should be reorganized. The most important aspects related to this topic should be clearly presented in order to provide a properly description of the state of art in this field. The degree of novelty of this study must be clearly stated and stressed, how is this paper different

-          please add these references in different places in the introduction

1.      Benettayeb, A.; Seihoub,F.Z.; Pal, P.; Ghosh, S.; Usman, M.;Chia, C.H.; Sillanpaa, M. ChitosanNanoparticles as Potential Nano-Sorbent for Removal of Toxic Environmental Pollutants.Nanomaterials 2023, 13, 447.https://doi.org/10.3390/nano13030447

2.      A. Benettayeb, A. Morsli, K.Z. Elwakeel, M.F. Hamza, E. Guibal, Recovery of heavy metal ions using magnetic glycine-modified chitosan—application to aqueous solutions and tailing leachate, Appl. Sci. 11 (2021) 8377. doi:10.3390/app11188377.

-          All abbreviations/notations should be explained in the main text the first time you use

-          Results and discussion section should be also reorganized. All experimental results must be clearly presented and detailed discussed, in accordance with the main objectives of this study.

-          you have to redo figure 1, try to improve the quality of this figure to show the importance of this work

-          I think you should delete table 1, and replace it with a small paragraph, you should add the details of the instruments when they will be used

-          same remark as table 2, you add the experimental conditions in the paragraphs which correspond to it and in the titles of the figures for ease of reading for the reader of this article

-          for the application of the Langmuir model

-          did you use 4 points to draw the isotherms? are these points sufficient? it is preferable to use non-linear modeling

-          Conclusion: This section should be rewritten. Include in this section only the most important experimental results and findings to highlight the importance of this study

Author Response

The changes made in the revised manuscript have been done by using track changes mode in MS Word. The replies to the reviewer’s comments are given in the blue colored text.                                        

Replies to Reviewer’s comments

We would like to begin by first thanking the reviewers for taking the time to review our manuscript and for the encouraging comments

Reviewer 2 Report

The research paper entitled “Green Synthesis of Zinc Hydroxide Nanoparticles Using Calotropis gigantea Leaf Extract and its Application in Removal of Toxic Coomassie Violet Dye from Aqueous Solutions: Optimization, Isotherm, Thermodynamic, and Kinetic Investigation (Manuscript ID ChemEngineering-2246245)” was reviewed. After reading the manuscript, I suggest to author to revise wisely for publication in ChemEngineering. Please do the revision for this manuscript based on comments below (major revision). This manuscript is not acceptable in this format.

1. In the abstract part, the researchers stated the importance of this study and did not explain about the results of this study.

2. The novelty of this research article compared to other studies is very low. There are many researches published in recent years about Zinc hydroxide.

3. What was the conclusion of the researchers about the effect of Zinc hydroxide on environmnetal applications?

4. Add ref for preparation section.

5. Redesign the methods chapter the way so anybody can repeat your procedures, like a recipe.

6. Add the table for the synthesis and applications of Zinc hydroxide.

7. SEM image is not enough for study detail of materials. Add TEM images in various scales.

8. Increase the quality of Fig.6.

9. The mechanism of photocatalyst is not clear. Please more explain and explain schematically.

10. Add new references for improve the environmental activity: Environmental Technology and Innovation (2021) 23,101560; Bioorganic Chemistry (2021) 115,105204; Environmental Technology and Innovation (2021) 23,101607;

11. The authors must revise the manuscript carefully to eliminate grammatical errors and typo-errors.

Author Response

The changes made in the revised manuscript have been done by using track changes mode in MS Word. The replies to the reviewer’s comments are given in the blue colored text.                                        

Replies to Reviewer’s comments

We would like to begin by first thanking the reviewers for taking the time to review our manuscript and for the encouraging comments

Author Response File: Author Response.docx

Reviewer 3 Report

This manuscript reported Zinc Hydroxide Nanoparticles utilized for dye removal through adsorption techniques. This work provides an idea about green synthesis of nanoparticle applied for adsorption process to treat wastewater. However, this manuscript needs major revisions and the following comments will help to increase the quality of the manuscript before publication.

·       Why did you select the Calotropis gigantean leaf part? Specify the detailed reason into the appropriate sections.

·       Some quantity results must be given in the abstract section.

·       In the "Introduction" section, general description on the importance of manuscript topic is poor. Therefore, the importance of this work cannot be well recognized from general readers. In order to fix this problem, addition of description on recent development in the field of research topic with citing recent comprehensive papers would be important. 
https://doi.org/10.1016/j.chemosphere.2023.138263;

·       How is the work different or better than those reported earlier? Author needs to highlight this in the introduction and discussion part.

·       Did you optimize yield of Zinc Hydroxide nanoparticle with different batch mode approach?

·       How did you filtered using any paper means mention that paper information? Why choice particularly filter paper for your experiment instead of others? What is the reason?

·       Why you choose particular Coomassie violet for adsorption activity. Why author not checked other dye compounds?

·       Instead of Figure author try to plot a scheme with chemical compound structure.  

·       Author should specify finally how did discard the used adsorbent in the open environment?

·       Which functional group majorly involve to degrade the dye in aqueous solution? State the convincing reason with suitable citation?

·       Author should make it simple and acknowledge the recommendation of present study in the conclusion section.

·       Among the kinetic/isotherm models which model is suites for adsorption process and describe it in dentally.

·       Extensive editing of English language and style required

·       Need to check consistency in reference the in text 

Author Response

The changes made in the revised manuscript have been done by using track changes mode in MS Word. The replies to the reviewer’s comments are given in the blue colored text.                                        

Replies to Reviewer’s comments

We would like to begin by first thanking the reviewers for taking the time to review our manuscript and for the encouraging comments

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Accept

Reviewer 3 Report

The author responded to all my comments and the editor can accept the revised version into the appropriate journal. Thank you