Recycling Discarded Facemasks of COVID-19 Pandemic to New Novel Composite Thermal Insulation and Sound-Absorbing Materials

Round 1

Reviewer 1 Report

The rationale of the study is not well-defined. The authors claim some exaggerated assertions that are challenging to prove. For instance, “The new developed materials will solve such a pollution problem in a scientifically safe way by applying the concept of the circular economy” or “Those materials are characterized as new novel promising sound-absorbing and thermal insulation for buildings.” I would suggest defining how promising those materials are. When it is stated for buildings, the authors should specify where those materials will be used: walls, ceiling, roof? The experiment has some lacks. For instance, the procedure they use to gather masks may affect the findings if they were collected from garbage bins. Also, the number of masks used in the study is not declared. It is necessary to redefine the scope of the experiment because the methodology does not allow it to probe what is concluded. It is needed to show the limitations of the study. I would suggest proofreading the document. 

Author Response

Please see the attachment.   Thank you.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper has an acceptable quality for publication and requires several adjustments

The authors are invited to

·         strengthen the problematisation part of introduction

·         clearly underline the area of their contribution after the literature review

·         contrast the findings with the existing literature

 

·         outline limitations and future research avenues

Author Response

Please see the attachment.  Thank you.

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear Author I have some comments:

Well-developed research with results for the protection of the environment.

1. Is it possible to include stability data (stability studies) of the composite samples over the time and predict their time of use?

2. Can you include a bio-deterioration study?

3. In conclusions can you be more specific in what types of buildings it can be used?

Congratulation for the work

Author Response

Please see the attachment.  Thank you.

Author Response File: Author Response.pdf

Reviewer 4 Report

The title of the paper "Recycling discarded facemasks of COVID-19 pandemic to new novel composite thermal insulation and sound-absorbing materials" is current.

The topic of recycling is a current topic, and the recycling of face masks is an intensely debated issue in the current context.

The authors present main directions to recycling the covid 19 face masks.

The research methodology and the main objectives are clearly presented.

I recommend the review following the following aspects:

1. Many abbreviations are used. Explanation of abbreviations used the first time they are used ((FE-SEM) (JEOL; JSM7600F))

2. The conclusions should be completed with descriptions of the best performance for each test made. The conclusions can be improved by taking into account previous research and literature review.

Author Response

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Author Response File: Author Response.pdf

Reviewer 5 Report

Abstract:

The authors need to improve the justification of the study. You can mention the need to develop new materials for use in artifacts in the health area that allow recycling or disposal with the least possibility of deleterious effects on the environment and/or public health.

 

Introduction:

Citations and references must be standardized according to the requirements established by Sustainability {eg: “line 42: Zorko et al[2]”}.

Lines 68-70: Rewrite this sentence in the “Materials and Method” section.

The authors mention the use of wood adhesive to prepare the composite materials, however, it is necessary to present previous studies present in the literature that justify the choice of this strategy for the elaboration of the composite.

Another point that was not clear is whether the researchers intend to propose a new composite production route or if they intend, through waste management and treatment, to propose the addition of value and return to the PPE production chain for the health sector. This information should become more evident, as it is possibly the premises that led the authors to formulate the hypothesis of the study presented.

In addition, the authors should present other studies in this section that present the reader with the state-of-the-art regarding the use of composite materials to produce masks, as well as the technical limitations that need to be overcome to increase the use of these new materials to the detriment of commercially available materials.

 

Materials and Method:

Overall, this section will need a number of adjustments, such as correcting, ordering, and standardizing sections and subsections. Additionally, figures and tables in this section must be resized and placed in subsections correctly.

Furthermore, the authors need to bring more information regarding the sampling. Additionally, it is necessary to know the number of masks (unit or total mass of masks), as well as the types of masks obtained for the development of this study. Authors may compile the information in Table 1 in terms of the sampling carried out in Section 2.1, rather than calling the table in Section 2.2.

In addition, authors must inform the period in which these studies were conducted (collections and experiments).

Regarding the figures and table 1 presented in this section, the authors must correct the text edition. The figures are superimposed on some legends and the table has poor formatting.

Authors must provide information on the chemical composition of wood adhesive.

Line 163: The correct abbreviation for the technique “Energy-dispersive X-ray spectroscopy” is EDS. Change the abbreviation EDX throughout the manuscript.

Regarding the characterization methods and techniques employed, the authors must mention the method, or mention the instrumental conditions employed in the SEM analyses. It is also necessary to report on the optimized EDS instrumental conditions employed for characterization.

 

Results and Discussion:

Initially, the authors begin by presenting the results of the characterization by SEM and EDS. As the EDS spectrometry technique presents analytically semiquantitative spectral results, it will be necessary to demonstrate the presence of Pt by comparing results from an AAS, ICP-OES or ICP-MS analysis. I believe that there was displacement and overlapping of the band signal in these readings. In this sense, these interferences may have led to the wrong conclusion about the presence of Pt in these samples.

Possibly, with the displacement of the sweep signal in the EDS, the element to be evaluated is Fe, instead of Pt. Another option will be to pass a certified platinum standard to verify the degree of shift of the spectra in relation to that observed in the analyses.

Lines 317-319: It is not possible to make this statement based on the results presented. Authors must remove these partial considerations.

The tables and figures presented in this section must also be corrected and duly formatted.

Lines 351-355: TGA results do not allow concluding the presented information. It only allows knowing the behavior and thermal stability of the proposed material. In this sense, authors should review and correct these considerations.

Line 400: check the called table number.

Lines 401 – 410: it is not possible to evaluate the information in figures 14. The lack of formatting and layout compromise the interpretation of the presented results.

After evaluating this section, it can be verified that the authors presented the results of characterization of the material and did not make any discussion with other studies in the literature to know if the new material presents any mechanical property of interest to the application in any productive chain, especially in the productive chain of production of personal protective equipment applied to health.

In addition, as the authors proposed the development of a new material to be applied specifically for mask production, microbiological stability studies are necessary to verify the behavior of this material.

 

Conclusion:

This section needs to be concise. The authors re-present the characterization results (lines 453 – 467). This information should be taken from this section. Study conclusions should be restricted to the information presented on lines 467 through 472.

Author Response

Please see the attachment.  Thank you

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Thank you for resubmitting your manuscript

Author Response

Thank you and I appreciate your time and effort in reviewing the manuscript.

Reviewer 2 Report

Accept in present form

Author Response

Thank you and I appreciate your time and effort in reviewing the manuscript.

Reviewer 5 Report

Introduction

line 89 - 94: remove sentence and apply it in the "Results and Discussion" section. End the introductory session with the purpose of the study.

Materials and methods

Authors need to correct all subsections as being part of the "Materials and Methods" section. Anyway, describe the adjustments of each subsection as presented in the manuscript

Section 2.1 - place figure 1 right after line 105.

Section 2.2 - place table 1, table 2 and figures 2 and 3 just after line 122. Additionally, I suggest replacing figure 2 with a flowchart containing only the description of the steps involved.

Despite the information presented in table 2 and lines 115 - 121 seem partial results, I realize the need for this placement in view of the volume of results obtained in the characterization and, consequently, allow a greater focus in the "Results and Discussion" section for data from microscopy, multielement analysis and thermal stability analysis and acoustic analysis.

Section 7, line 241: replace figure 4 after table 3

Results and discussion

The way it was presented and organized, it allowed understanding the purpose of each test used for the characterization and determination of the mechanical properties of the different test samples.

The appearance of platinum in the investigated samples was better explained, as being part of the abrasion effect on the container. In addition, it was clear why there was no appearance of iron in the EDS analyzes due to the nature of the composites.

line 409 - 422: organize the essay as a whole

In addition, it was possible to observe the discussion of the results and the comparison with a previously published study or with some technical reference, according to ASTM guides.

Furthermore, it would be interesting for the authors to mention if there was any technical reason or apparent reason for not crushing and homogenizing the discarded masks before preparing the composites.

Conclusions

The conclusions are well descriptive and summarized, reporting better to the results obtained and proposed objective.

After reassessing the manuscript, I consider it necessary to make some adjustments before accepting it for publication. The adjustments and notes are described throughout this opinion

 

 

Author Response

Please see the attached file.

Author Response File: Author Response.pdf