Activated Carbon Electrodes for Bioenergy Production in Microbial Fuel Cells Using Synthetic Wastewater as Substrate

Round 1

Reviewer 1 Report

This study evaluated the efficiency of activated carbon anode electrodes for bioenergy production in MFC using synthetic wastewater as a substrate to develop an economic, eco-friendly, and eco-efficient MFC to generate sustainable bioelectricity. But before this study can be accepted for publication, the minor modifications need to be made. The detailed comments are as follows:

1.     The third paragraph in the introduction explains that the focus of the manuscript is on the anode electrode, so there is no detailed discussion on the cathode. However, it is still necessary to introduce what cathode electrode is used in the manuscript and the reasons for choosing this material as the cathode electrode.

2.     The introduction lacks a description of choosing synthetic wastewater as the substrate.

3.     The description of other references in the Introduction should be reduced and the Introduction should be focused on the gap to be addressed in this study.

4.     To better understand the research content and results, it is necessary to display all the figures and tables in the main text, such as Figure 1 and Table 1.

5.     Line 131, does "4 waterproofed electrode" mean four waterproofed electrodes? And line 245 what does "day 1.30" mean? Suggest checking the manuscript to avoid such issues from recurring

6.     Lines 224-231, There is too much description of other references in the manuscript, and more attention should be paid to the differences with other studies, and the possible reasons for their differences should be analyzed.

7.     There is too much content in the conclusion, it should be refined.

8.     The figures and tables need to be further beautified to achieve better results.

9.     The language should be edited. A general revision of English by a native speaker is needed to improve the quality of the manuscript.

 Extensive editing of English language required

Author Response

Dear colleague, I hope you are very well. The authors made the suggested corrections and have responded to each of the comments made.

1. The third paragraph in the introduction explains that the focus of the manuscript is on the anode electrode, so there is no detailed discussion on the cathode. However, it is still necessary to introduce what cathode electrode is used in the manuscript and the reasons for choosing this material as the cathode electrode.
Ans. Information about the cathode was added and an attempt was made to justify the type of material used for this electrode (55-64).
2. The introduction lacks a description of choosing synthetic wastewater as the substrate.
Ans. A brief information about synthetic wastewater was added, because the study focused on placing information regarding the anode and carbon material used.
3. The description of other references in the Introduction should be reduced and the Introduction should be focused on the gap to be addressed in this study.
Ans. Some references have been removed and some lines have been rewritten for a better understanding.
4. To better understand the research content and results, it is necessary to display all the figures and tables in the main text, such as Figure 1 and Table 1.
Ans. For a better understanding the authors eliminated some tables and rearranged the methodology, I hope you like it.
5. Line 131, does "4 waterproofed electrode" mean four waterproofed electrodes? And line 245 what does "day 1.30" mean? Suggest checking the manuscript to avoid such issues from recurring
ANS. On line 131, all the methodology for rewrote was corrected. About the observation in line 245, due to be day 13; the error was corrected.
6. Lines 224-231, There is too much description of other references in the manuscript, and more attention should be paid to the differences with other studies, and the possible reasons for their differences should be analyzed.
Ans, several points of the manuscript have been corrected.
7. There is too much content in the conclusion, it should be refined.
Ans. The conclusions were rewrote

8. The figures and tables need to be further beautified to achieve better results.
Ans. It may be due to an error converting to magazine format, but we have improved the resolution.
9. The language should be edited. A general revision of English by a native speaker is needed to improve the quality of the manuscript.
Ans. English was revised.

 

kind regards

Author Response File: Author Response.docx

Reviewer 2 Report

In this study, bioenergy production was carried out using activated carbon electrodes in a synthetic wastewater environment. This research is original research in general but authors need to clarify and revise the manuscript. Suggestions are listed below.

1- Abbreviations should be used broadly where they are mentioned for the first time, then only abbreviations should be used in subsequent places. Like ORP, NTU, AC…

2- Lines 55-59: these lines should be combined with the last paragraph of the introduction (line 98) and revised again.ine 55-59 

3- Line 101: Superscript should be written properly.

4- Line 110: What does the sentence starting with "g of granular activated carbon (GAC)" mean?

5- The number of times the analyzes were repeated should be written.

6- Section 2.1. Reference should be made to the literature for the method used in "Manufacture of granular activated carbon (GAC) electrodes".

7- Section 2.2. Appropriate reference should be given.

8- Again, on which reference was the method applied in section 2.3 based?

9- Table 1 not cited in the text?

10- It would be useful to move Figure 2 to the supplementary material file.

11- Again, reference is required for the Substrate preparation section.

12- There is a difference in font and quality in Figure 4a and b, it should be updated.

13- The font of the letters a, b and c in Figure 5 is different from the Figure main font and font size.

14- It will be easier for the reader if Figure 3a and b appear in one graph.

15- Why is the Si peak in Figure 7 so high?

16- The conclusion part can be a little deeper.

Average

Author Response

Dear colleague, I hope you are very well. The authors made the suggested corrections and have responded to each of the comments made.

1- Abbreviations should be used widely where they are mentioned for the first time, then only abbreviations should be used in subsequent places. Like ORP, NTU, AC…
Ans. It was corrected.
2- Lines 55-59: these lines should be combined with the last paragraph of the introduction (line 98) and revised again.ine 55-59
Ans. It was corrected. These paragraphs were rewritten.
3- Line 101: Superscript should be written properly.
Ans. It was corrected.
4- Line 110: What does the sentence starting with "g of granular activated carbon (GAC)" mean?
Ans. It was corrected. It was a writing error.
5- The number of times the analyzes were repeated should be written.
Ans. It was added that three measurements of each parameter were used to obtain the means of the values (line 171-172).
6-Section 2.1. Reference should be made to the literature for the method used in "Manufacture of granular activated carbon (GAC) electrodes".
Ans. The method for the elaboration of the electrode based on granulated activated carbon was not taken from another reference, since the procedure was innovated in our laboratory. However, this method can be taken as a guide for other authors.
7-Section 2.2. Appropriate reference should be given.
Ans. Like the previous answer it was not taken from some preset method. Our electrodes are innovative and their manufacturing and waterproofing was implemented for the first time in this research work.
8- Again, on which reference was the method applied in section 2.3 based?
Ans. The methodology of the manuscript has been modified, but in the previous manuscript the method was totally empirical; It has taken us a long time to make this electrode.
9- Table 1 not cited in the text?
Ans. Table 1 was modified and the results of the evaluation of the electrodes based on activated carbon were placed inside the substrate (synthetic wastewater). This part of the methodology was also modified and the results were placed in the corresponding section.
10- It would be useful to move Figure 2 to the supplementary material file.
11- Again, reference is required for the Substrate preparation section.
12- There is a difference in font and quality in Figure 4a and b, it should be updated.
Ans. were improved
13- The font of the letters a, b and c in Figure 5 is different from the Figure main font and font size.
Ans. were standardized
14- It will be easier for the reader if Figure 3a and b appear in one graph.
Ans. We have always presented it that way so as not to incur confusion.
15- Why is the Si peak in Figure 7 so high?
Ans. The presence of Si is due to the content present within the activated carbon because in the initial shift, the presence of Si was also noted.
16- The conclusion part can be a little deeper.
Ans: the conclusions were redescribed.

 

kind regards

Author Response File: Author Response.docx

Reviewer 3 Report

In the present work, Rojas-Flores and coworkers evaluated the use of activated carbon as anode electrodes in a microbial fuel cell fed with synthetic wastewater. The manuscript deals with an interesting topic, and it is overall well written. However, some points should be improved before proceeding with its publication

·       In the abstract, the meaning of the acronyms should be clarified

·       The apexes in the unit measures should be corrected (e.g. in row 89)

·       In the introduction, the novelty of the work should be highlighted

·       Correct the sentence in row 110; have you evaluated how much is the powder fine? Using a sieve?

·       What is the reproducibility of the tests? Have you carried them out in duplicate or triplicate?

·       Some reasons with respect to the differences observed from other works (discussion from row 188) should be reported

·       Have you evaluated if some possible degradation phenomena occurred in the electrodes?

Moderate editing of English language required

Author Response

Dear colleague, I hope you are very well. The authors made the suggested corrections and have responded to each of the comments made.

· In the abstract, the meaning of the acronyms should be clarified.
Ans. The abbreviations were clarified, but the units of the values are placed as they are.

Vertices must be corrected in unit measures (for example, in row 89)
Ans. It was reviewed.
· The introduction should highlight the novelty of the work.
Ans. The correction was made.

· Correct the sentence in row 110; Have you evaluated how fine the powder is? Using a strainer?
Ans. The used activated carbon was passed through a 10 um sieve.

· What is the reproducibility of the tests? Have you done them in duplicate or triplicate?
Ans. As previously mentioned, the measurements were performed in triplicate for each parameter to obtain the means of the values (line 171-172).

· Some reasons should be reported regarding the differences observed with other works (discussion of row 188)
Ans. was added
· Have you evaluated whether there were any possible degradation phenomena in the electrodes?
Ans. An evaluation of the percentage of weight loss of the electrodes was made at the end of the experiment (line 409 - 414).

 

kind regards

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

It may be published in an edited form.

Reviewer 3 Report

The manuscript was improved and it can be now accepted