Biogenic Synthesis Based on Cuprous Oxide Nanoparticles Using Eucalyptus globulus Extracts and Its Effectiveness for Removal of Recalcitrant Compounds

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript is good idea and good written but some revision is essential prior publication 

The abstract should be re written it should include the quantitative data and informative not written in short way and not informative 

Novelty of the work please should be written at the end of abstract and introductory part

Illustrate in the introduction part the previous data and the essential of using the current study 

 

Add literature review comparison may be in a table to compare the work with the previous one to illustrate the contribution of the current work 

In conclusion section please add the future prospects 

Discussion through the manuscript should be overall improved and may be supported with literature

 

“paper is show in Figure 3a. The Figure 3b show..”

L242 p6 

English need to be revised 

Please 

Please illustrate why use cupper nanoparticles specifically instead of iron and the advantages of this use, some reference may be helpful in this point such as:

https://doi.org/10.1007/s13762-019-02436-x

Section 3.1.2. “spherical shape” it is unclear from SEM image may be TEM is needed 

Also the particles are described “varied from 32.3 to 142 nm,”

Som it is more than 100 nm so we could not say nano scale 

Why the catalyst as well as hydrogen peroxide doses are not checked on what basis the certain doses are added

Comments on the Quality of English Language

The manuscript is good idea and good written but some revision is essential prior publication 

The abstract should be re written it should include the quantitative data and informative not written in short way and not informative 

Novelty of the work please should be written at the end of abstract and introductory part

Illustrate in the introduction part the previous data and the essential of using the current study 

 

Add literature review comparison may be in a table to compare the work with the previous one to illustrate the contribution of the current work 

In conclusion section please add the future prospects 

Discussion through the manuscript should be overall improved and may be supported with literature

 

“paper is show in Figure 3a. The Figure 3b show..”

L242 p6 

English need to be revised 

Please 

Please illustrate why use cupper nanoparticles specifically instead of iron and the advantages of this use, some reference may be helpful in this point such as:

https://doi.org/10.1007/s13762-019-02436-x

Section 3.1.2. “spherical shape” it is unclear from SEM image may be TEM is needed 

Also the particles are described “varied from 32.3 to 142 nm,”

Som it is more than 100 nm so we could not say nano scale 

Why the catalyst as well as hydrogen peroxide doses are not checked on what basis the certain doses are added

Author Response

Editor

Editors-in-Chief

Catalysts

 

 

Concepción (Chile), August 2nd, 2024

Dear Editor,

Please find here with the revised version of the manuscript “Biogenic synthesis based on cuprous oxide nanoparticles using Eucalyptus globulus extracts and its effectiveness for removal recalcitrant compounds” by Pablo Salgado, Katherine Márquez, and Gladys Vidal assigned as Manuscript ID: catalysts-3131052.

We want to thank the reviewers for carefully reading the manuscript. All the comments were attended, and the paper was carefully checked according to the editorial suggestions.

The following comments indicate our response to all the questions and notes indicated by the Reviewer #1. Please consider that unless otherwise expressed, the referenced lines correspond to the current numeration after the corrections were made.

REVIEWER # 1

- Comment 1: The manuscript is good idea and good written but some revision is essential prior publication. The abstract should be re written it should include the quantitative data and informative not written in short way and not informative 

- Answer 1: Thank you very much for the suggestion. We have rewritten the abstract including quantitative information.

 

- Comment 2: Novelty of the work please should be written at the end of abstract and introductory part. Illustrate in the introduction part the previous data and the essential of using the current study.

- Answer 2: The novelty of the publication is briefly mentioned at the end of the abstract and the introduction. We have mentioned some similar previous work using suspended nanoparticles to improve the clarity of testing supported nanoparticles.

 

 

- Comment 3: Add literature review comparison may be in a table to compare the work with the previous one to illustrate the contribution of the current work.

 - Answer 3: A comparison table obtained from a literature review of systems similar to the one studied in this work had initially been attached in the supplementary material, however, we have now added it to the main paper.

 

- Comment 4: In conclusion section please add the future prospects 

- Answer 4: Thank you very much for the comment. We have added future work that can be done for these systems in order to better understand their properties and performance.

 

- Comment 5: Discussion through the manuscript should be overall improved and may be supported with literature

- Answer 5: Adding the table of other investigations in similar systems has led to an improvement in the discussion of results.

 

- Comment 6: “paper is show in Figure 3a. The Figure 3b show..” L242 p6. English need to be revised 

- Answer 6: We have reviewed and corrected some issues with English.

 

- Comment 7: Please illustrate why use cupper nanoparticles specifically instead of iron and the advantages of this use, some reference may be helpful in this point such as:

https://doi.org/10.1007/s13762-019-02436-x

- Answer 7: In the introduction section, some advantages of using copper instead of iron were mentioned. The suggested research is very appropriate for this topic, so it has been added.

 

- Comment 8: Section 3.1.2. “spherical shape” it is unclear from SEM image may be TEM is needed 

- Answer 8: Thank you very much for the comment. We agree with what you suggested, so we have removed the sentence that suggested the shape of the nanoparticles using SEM analysis.

 

- Comment 9: Also the particles are described “varied from 32.3 to 142 nm,” Som it is more than 100 nm so we could not say nano scale 

- Answer 9: We agree that the general rule is not to consider particles larger than 100 nm to be called nanoparticles (although there are some who differ from this definition: https://doi.org/10.1016/j.tibtech.2007.09.005, https://doi.org/10.1016/j.cis.2015.11.010). However, in our work only 4.42% of the nanoparticles have a size greater than 100 nm, so we believe that in general we obtained nanoparticles.

 

- Comment 10: Why the catalyst as well as hydrogen peroxide doses are not checked on what basis the certain doses are added

- Answer 10: Thank you very much for the comment. The reason for not studying the effect of catalyst and H₂O₂ dosages on MB removal was that we wanted to focus this publication on the formation, characterization, and a study of its relatively simple effectiveness using the proposed reactor. With the information already obtained here we can plan to study the effect of other parameters on the removal of MB or other contaminants.

 

 

Yours sincerely,

 

 

Prof. Gladys Vidal

Engineering and Environmental Biotechnology Group

Environmental Science Faculty & Center EULA-Chile

Universidad de Concepción, Concepción, Chile.

 

E-mail: [email protected]; ww.eula.cl/giba

Reviewer 2 Report

Comments and Suggestions for Authors

A paper entitled “Biogenic synthesis based on cuprous oxide nanoparticles using Eucalyptus globulus extracts and its effectiveness for removal recalcitrant compounds” describes the efficacy of green-formed Cu2O@CBP on the degradation of MB under photocatalytic and Fenton-like reactions. The synthesized NPs were characterized by SEM, XRD, Raman, FTIR, UV-Vis DRS, and TGA. The manuscript contains promising data and can be accepted for publication after major revision.

1-     Line 19, the abbreviations should be mentioned completely the first time. Please check and revise throughout the manuscript.

2-     Lines 113 – 128, it should be concise to be clearer

3-     Line 131, the scientific names must be italics, please check and revise throughout the manuscript.

4-     The material and method section lacks the appropriate citations. Please check and cite references.

5-     Line 253, “cm-1” should be “cm^-1”, please check and revise the typo-error throughout the manuscript.

6-     The characterization section in (Results and Discussion) needs deep discussion.

7- The authors investigated the effect of pH on the catalytic activity and neglected other optimizing parameters such as contact times, MB concentrations, etc.

8-     The authors should explain the reason for the decline in the efficiency of synthesized Cu2O@CBP from 57 to 46% or 67 to 44%. This decline will decrease the efficacy of synthesized material.

9-     The authors should be investigating the potential of synthesized material in the degradation of other pollutants or raw wastewater.

 

 

Comments on the Quality of English Language

Moderate editing of English language required

Author Response

Editor

Editors-in-Chief

Catalysts

 

 

Concepción (Chile), August  2nd, 2024

Dear Editor,

Please find here with the revised version of the manuscript “Biogenic synthesis based on cuprous oxide nanoparticles using Eucalyptus globulus extracts and its effectiveness for removal recalcitrant compounds” by Pablo Salgado, Katherine Márquez, and Gladys Vidal assigned as Manuscript ID: catalysts-3131052.

We want to thank the reviewers for carefully reading the manuscript. All the comments were attended, and the paper was carefully checked according to the editorial suggestions.

The following comments indicate our response to all the questions and notes indicated by the Reviewer #2. Please consider that unless otherwise expressed, the referenced lines correspond to the current numeration after the corrections were made.

REVIEWER # 2

- Comment 1: A paper entitled “Biogenic synthesis based on cuprous oxide nanoparticles using Eucalyptus globulus extracts and its effectiveness for removal recalcitrant compounds” describes the efficacy of green-formed Cu2O@CBP on the degradation of MB under photocatalytic and Fenton-like reactions. The synthesized NPs were characterized by SEM, XRD, Raman, FTIR, UV-Vis DRS, and TGA. The manuscript contains promising data and can be accepted for publication after major revision.

Line 19, the abbreviations should be mentioned completely the first time. Please check and revise throughout the manuscript.

- Answer: We appreciate the reviewer bringing the problem with the abbreviations to our attention. We have corrected these problems where we have found them.

 

- Comment 2: Lines 113 – 128, it should be concise to be clearer

- Answer: We appreciate the reviewer's suggestion. We have shortened the paragraph to make it clearer.

 

 

- Comment 3: Line 131, the scientific names must be italics, please check and revise throughout the manuscript.

- Answer: We have corrected the error.

 

 

- Comment 4: The material and method section lacks the appropriate citations. Please check and cite references.

- Answer: More references were added to the methodology section

- Comment 5: Line 253, “cm-1” should be “cm^-1”, please check and revise the typo-error throughout the manuscript.

- Answer: We have corrected the error.

 

- Comment 6: The characterization section in (Results and Discussion) needs deep discussion.

- Answer: Thank you very much for the suggestion. We have extended the discussion in some parts regarding the characterization of nanoparticles.

 

- Comment 7: The authors investigated the effect of pH on the catalytic activity and neglected other optimizing parameters such as contact times, MB concentrations, etc.

- Answer: Thank you for your comment. We recognize the importance of considering other parameters in the performance of nanoparticles for dye removal. However, for the purpose of this study, our focus was on testing the formation of Cu₂O@CBP through the described process and demonstrating their identity and properties through characterization techniques. To fully understand the role of additional parameters in contaminant removal (such as contact times, MB concentrations, etc.), a large number of experiments would be required, which could be addressed in a separate publication. The selection of the parameter "pH" in contaminant removal was based on its crucial role in comparing the effectiveness of photocatalytic activity and Fenton-type reactions. The importance of pH can be attributed to its impact on the adsorption of contaminants on the surface of nanoparticles before photocatalysis or Fenton-type catalysis, as well as its influence on the chemical processes involved (such as protonation or deprotonation of H₂O₂). We chose pH 7.0 to determine the effectiveness of Cu₂O@CBP at a neutral pH, similar to that of natural waters or some wastewaters. Additionally, we selected pH 3.0 as it is typically the optimal pH for Fenton systems.

https://doi.org/10.1016/j.jhazmat.2006.06.093

https://doi.org/10.1088/1742-6596/1011/1/012069

https://doi.org/10.30492/ijcce.2020.39879

https://doi.org/10.5004/dwt.2019.24760

https://doi.org/10.1016/j.enmm.2019.100265

https://doi.org/10.33640/2405-609X.3217

 

 

- Comment 8: The authors should explain the reason for the decline in the efficiency of synthesized Cu2O@CBP from 57 to 46% or 67 to 44%. This decline will decrease the efficacy of synthesized material.

- Answer: Thank you very much for the suggestion. While an explanation was already included that attempts to give reasons for the greater decrease in yield in the Fenton-like process, a reason was added that could explain the decrease in yield for photocatalysis and Fenton-like.

 

 

- Comment 9: The authors should be investigating the potential of synthesized material in the degradation of other pollutants or raw wastewater.

- Answer: Thank you very much for the suggestions. We agree with the reviewer, and we believe that the next steps in future research could be to study other variables in addition to pH, and the effectiveness in removing other contaminants.

Methylene blue (MB) has been extensively studied in the past, yet it remains a prevalent model for refractory organic pollutants in esteemed scientific journals due to its widespread presence in various effluents, its toxicity, and the ease with which it can be monitored using spectrophotometry.

https://doi.org/10.1016/j.cej.2024.148622

https://doi.org/10.1016/j.cej.2023.147320   

https://doi.org/10.1016/j.cej.2024.152634  

https://doi.org/10.1016/j.cej.2024.152102  

https://doi.org/10.1016/j.apcatb.2023.123199  

https://doi.org/10.3390/nano14090765  

https://doi.org/10.3390/nano14020132  

https://doi.org/10.3390/nano13182548

Although the outcomes of our study might vary with a different contaminant, we assert that using MB provides valuable comparative data, aligning our findings with numerous other studies that have utilized MB as a benchmark.

 

 

Yours sincerely,

 

 

Prof. Gladys Vidal

Engineering and Environmental Biotechnology Group

Environmental Science Faculty & Center EULA-Chile

Universidad de Concepción, Concepción, Chile.

 

E-mail: [email protected]; ww.eula.cl/giba

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear authors,

            The synthesis of Cu2O via green approach forms the central part of the research work and their ability to degrade MB dye through Fenton process and the photocatalytic reactions are reasonable to appreciate with. The discussion is clear-cut throughout the article and experimental data are reasonable to appreciate with. The listed comments may be considered to further improve the quality of the article.

 

Minor comments

 

Abstract

(1) The crystal structure and the crystallite size of Cu2O may be emphasized.

(2) The optical response of Cu2O may be specified.

 

Section 2.0

(1) The geographical location related to the collection of Eucalyptus leaves should be clearly expressed.

(2) Does the reduction of Cu(OH)2 to Cu2O proceed only at higher temperature (333 K)? Is it not possible to attain the same reduction at room temperature?

(3) The solution pH at which reduction reaction was carried out may be indicated.

 

Results and discussion

(1) The particle size of Cu2O obtained without the addition of leaves extract should also be amended to realize their beneficial effects.

(2) How about the leaching of Cu+ ions at the end of the reaction?

 

Author Response

Editor

Editors-in-Chief

Catalysts

 

 

Concepción (Chile), August 2nd, 2024

Dear Editor,

Please find here with the revised version of the manuscript “Biogenic synthesis based on cuprous oxide nanoparticles using Eucalyptus globulus extracts and its effectiveness for removal recalcitrant compounds” by Pablo Salgado, Katherine Márquez, and Gladys Vidal assigned as Manuscript ID: catalysts-3131052.

We want to thank the reviewers for carefully reading the manuscript. All the comments were attended, and the paper was carefully checked according to the editorial suggestions.

The following comments indicate our response to all the questions and notes indicated by the Reviewer #3. Please consider that unless otherwise expressed, the referenced lines correspond to the current numeration after the corrections were made.

REVIEWER # 3

- Comment 1: The synthesis of Cu2O via green approach forms the central part of the research work and their ability to degrade MB dye through Fenton process and the photocatalytic reactions are reasonable to appreciate with. The discussion is clear-cut throughout the article and experimental data are reasonable to appreciate with. The listed comments may be considered to further improve the quality of the article.

 

The crystal structure and the crystallite size of Cu2O may be emphasized.

- Answer: Thank you very much for the suggestion. Some comments have been added to emphasize the structure and size aspects of the nanoparticles obtained.

 

 

- Comment 2: The optical response of Cu2O may be specified.

- Answer: Thank you for the suggestion. It seems that the reviewer may be suggesting the use of photoluminescence analysis to assess the optical response of Cu₂O. This would provide valuable insights into the separation and recombination of charges within the semiconductor. Additionally, it would be intriguing to investigate the impact of the support or phenolic compounds on these processes. While we hope to conduct this analysis in the future, we have not yet been able to find other research centers to collaborate with on this matter.

 

 

- Comment 3: Section 2.0

(1) The geographical location related to the collection of Eucalyptus leaves should be clearly expressed.

- Answer: Thank you very much for the suggestion. The location where the leaves were collected has been added.

 

 

- Comment 4: (2) Does the reduction of Cu(OH)2 to Cu2O proceed only at higher temperature (333 K)? Is it not possible to attain the same reduction at room temperature?

- Answer: Thank you for your insightful observation. The temperature used in our experiment was determined after conducting several previous experiments to test the synthesis method at various temperatures. Our findings showed that at room temperature, using the extracts, nanoparticles did not form on the paper within a three-day period. However, as we increased the temperature of the medium, we began to see the formation of nanoparticles. We chose not to test the reaction at temperatures higher than 60 °C due to evidence of potential chemical changes that could occur in phenolic compounds at temperatures equal to or greater than 70 °C, such as polymerization and degradation.

 

 

- Comment 5: The solution pH at which reduction reaction was carried out may be indicated.

 - Answer: Thank you for your comment. After conducting our experiment, we found that the pH of the aqueous extract of eucalyptus was consistently around 5.0. However, when we applied it to paper that was saturated with Cu(OH)₂, the pH increased significantly to approximately 8.5. We have included this data in our publication.

 

 

 

- Comment 6: Results and discussion

(1) The particle size of Cu2O obtained without the addition of leaves extract should also be amended to realize their beneficial effects.

- Answer: Unfortunately, for this publication we did not synthesize nanoparticles without the intervention of eucalyptus extract. However, for your consideration, in other research we are working on, a direct effect is observed in the reduction of the size of the nanoparticles, and in some cases it even improves the dispersion (prevents agglomerations) on the supports.

 

 

 

- Comment 7: (2) How about the leaching of Cu+ ions at the end of the reaction?

- Answer: We appreciate the reviewer's suggestion, as this is an interesting topic to address in order to understand in particular the nanomaterial losses that could be caused especially by the Fenton-like reaction. However, we do not currently have a technique available in our laboratory to measure total copper. Our current method only allows us to measure Cu²⁺ using the bicinchoninic acid method, but it does not differentiate between Cu⁺ in solution. While we could potentially measure copper using atomic absorption, this would require a significant amount of time to re-synthesize the nanoparticles and wait for access to the necessary equipment.

 

 

Yours sincerely,

 

 

 

 

Prof. Gladys Vidal

Engineering and Environmental Biotechnology Group

Environmental Science Faculty & Center EULA-Chile

Universidad de Concepción, Concepción, Chile.

 

E-mail: [email protected]; ww.eula.cl/giba

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

This manuscript presents an interesting study on the preparation of cuprous oxide nanoparticles on cellulose-based paper (Cu2O@CBP) using Eucalyptus globulus leaf extracts. The synthesized catalysts exhibited efficient degradation of methylene blue (MB) through photocatalytic and heterogeneous Fenton-like reactions. The characterizations and experimental work are relatively complete and valuable, contributing a significant and novelty aspect to the field. The main conclusions are believable. However, several sections require additional details or explanations to clarify points and support arguments. Therefore, I suggest a major revision of the manuscript based on the following comments:

 

1.     The second paragraph of the introduction is too long. It is recommended that the authors shorten it and highlight the innovation of the manuscript. The Introduction part should be improved with relevant literature, for example: Separation and Purification Technology 305 (2023) 122437.

2.     A broad consensus is that the evaluation of decoloration of organic dyes has serious problems(such as photosensitization). The authors should try more pollutants.

3.     Figure 2 lacks a scale bar.

4.     Raman and FTIR analyses are incorrect. It is recommended that the author reanalyze and focus on the main peaks.

5.     The effect of dissolved Cu ions on the degradation of MB should also be investigated. Please add a homogeneous control experiment to determine the effect of leaching Cu ions. Additionally, some natural water samples can be used to evaluate the catalytic efficiency of Cu2O@CBP. For example: Chemical Engineering Journal 476 (2023) 146523.

 

6.     In Figure 6, the authors need to provide Cu2O data for comparison.

Comments on the Quality of English Language

Some of the English grammatical errors need to be corrected.

Author Response

Editor

Editors-in-Chief

Catalysts

 

 

Concepción (Chile), August 2nd, 2024

Dear Editor,

Please find here with the revised version of the manuscript “Biogenic synthesis based on cuprous oxide nanoparticles using Eucalyptus globulus extracts and its effectiveness for removal recalcitrant compounds” by Pablo Salgado, Katherine Márquez, and Gladys Vidal assigned as Manuscript ID: catalysts-3131052.

We want to thank the reviewers for carefully reading the manuscript. All the comments were attended, and the paper was carefully checked according to the editorial suggestions.

The following comments indicate our response to all the questions and notes indicated by the Reviewer #3. Please consider that unless otherwise expressed, the referenced lines correspond to the current numeration after the corrections were made.

REVIEWER # 3

- Comment 1: This manuscript presents an interesting study on the preparation of cuprous oxide nanoparticles on cellulose-based paper (Cu2O@CBP) using Eucalyptus globulus leaf extracts. The synthesized catalysts exhibited efficient degradation of methylene blue (MB) through photocatalytic and heterogeneous Fenton-like reactions. The characterizations and experimental work are relatively complete and valuable, contributing a significant and novelty aspect to the field. The main conclusions are believable. However, several sections require additional details or explanations to clarify points and support arguments. Therefore, I suggest a major revision of the manuscript based on the following comments:

 

The second paragraph of the introduction is too long. It is recommended that the authors shorten it and highlight the innovation of the manuscript. The Introduction part should be improved with relevant literature, for example: Separation and Purification Technology 305 (2023) 122437.

- Answer: Thanks for the suggestion. We have removed some sentences to shorten the paragraph. Additionally we have added the suggested publication.

 

 

- Comment 2: A broad consensus is that the evaluation of decoloration of organic dyes has serious problems (such as photosensitization). The authors should try more pollutants.

- Answer: Indeed, photosensitization is an effect that is sometimes not desired in this type of process. Although we have plans to continue working with the Cu₂O@CBP system degrading other dyes, we had not considered studying photosensitization. We appreciate your suggestion, which will be considered in future work.

However, there is a research in which the photosensitization of Cu₂O using MB was studied (https://doi.org/10.1021/acsanm.2c00730). The authors found that the main reactive species produced by the photosensitization of MB on Cu₂O is O₂·-, unlike the present work in which there does not seem to be evidence of the production of O₂·- when irradiated with visible light, but rather it produces mostly ·OH radicals. Therefore, it is possible that the photosensitization is not relevant in our system.

 

- Comment 3: Figure 2 lacks a scale bar.

- Answer: The size of the piece of material was added to the name of the figure.

 

- Comment 4: Raman and FTIR analyses are incorrect. It is recommended that the author reanalyze and focus on the main peaks.

- Answer: We appreciate the suggestion, but we must comment that we do not agree that the FTIR and Raman analyses are incorrect. Raman shows many signals, but we believe that they are worth mentioning because they provide evidence of the effective formation of Cu₂O and its interaction with phytochemicals. Similarly, we believe that it is important to identify which signals change and which remain unchanged in the FTIR analysis, in order to propose the involvement of specific functional groups in the formation of the nanoparticles and their interactions with other functional groups. In order to respond appropriately to the reviewer's comments, it would have been helpful if the specific aspects of the analyses that are considered incorrect were indicated.

 

- Comment 5: The effect of dissolved Cu ions on the degradation of MB should also be investigated. Please add a homogeneous control experiment to determine the effect of leaching Cu ions. Additionally, some natural water samples can be used to evaluate the catalytic efficiency of Cu2O@CBP. For example: Chemical Engineering Journal 476 (2023) 146523.

- Answer: We appreciate the reviewer's suggestion. However, in our laboratory we do not have a technique to measure total copper. We only have a technique to measure Cu²⁺ using the bicinchoninic acid method, but we would not be able to differentiate Cu⁺ in solution. We could manage to measure copper by atomic absorption, but it would take us a long time to re-synthesize the nanoparticles and wait for our turn for the equipment.

 

- Comment 6: In Figure 6, the authors need to provide Cu2O data for comparison.

• Answer: Thanks for the suggestion, however, the graph in Figure 6 does indeed show Cu₂O data on cellulose-based paper. However, between the 327 and 335 lines, a discussion was added regarding band-gap values that have been found in other investigations for Cu₂O of similar sizes.

 

Yours sincerely,

 

 

 

 

Prof. Gladys Vidal

Engineering and Environmental Biotechnology Group

Environmental Science Faculty & Center EULA-Chile

Universidad de Concepción, Concepción, Chile.

 

E-mail: [email protected]; ww.eula.cl/giba

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Accept in the current form the manuscript is improved 

Reviewer 2 Report

Comments and Suggestions for Authors

Thanks for revised manuscript based on reviewers comments 

Comments on the Quality of English Language

 Moderate editing of English language required

Reviewer 4 Report

Comments and Suggestions for Authors

Accept