Catalytic Degradation of Bisphenol A in Water by Poplar Wood Powder Waste Derived Biochar via Peroxymonosulfate Activation

Round 1

Reviewer 1 Report

Generally, presented manuscript entitled “Exploration of the catalytic activation capability of poplar wood powder waste pyrolyzed bio-char for organic pollutant degradation in water” is written with the very good English and the whole construction is concise and precise. However, some corrections, listed below, are needed.

·         In the Title, word “biochar” is written with dash, however later, without it. Please unify.

·         Lines 36-37: “Due to the merits of room-temperature activation and rapid active radical generation rates [5]” – this sentence is somehow cut in the middle.

·         Among the text, there are many words incorrectly written with dash in the middle: “function-al”, “ana-lyze”, “con-tribute”, “degrada-tion” etc.

·         Lines 50-51: “Meanwhile, few studies have explored the potential of introducing wood powder waste in fine processing and high added-value applications” - can Authors provide any citation?

·         Lines 69-71: “[…] was calcined in a tubular furnace with a heating rate of 5°C/min under N₂ atmosphere from room temperature to 200°C for 1h, and then heated to desired temperature, stayed at this temperature for 3h.” – if I understand correctly, the “room temperature -> 200°C” heating was a pretreatment. However, did it stayed at 200°C for 1h or the temperature increasing process lasted 1h?

·         In some parts of the text (especially references) subscripts are missing.

·         Line 96: word “L-histidine” is written in italic, when in the rest of the text not. Please unify.

·         Figure 1. Please add visible scale bars to the SEM pictures.  

·         Lines 108-109: “The average particle size of obtained PPB sample became smaller with the increase of the pyrolysis temperature […]” – what are exact sizes of particles for all samples?

·         Figure 2a: XRD of sample PPB-400 looks different than others. What is the possible reason? I also suggest using the same color for each sample on every Figure (e.g., PPB-400 – red, PPB-600 – blue, and so on). With this readers could compare results in easier way.

·         Line 150: I think word “declined” is not very accurate when describing decreasing of XPS peaks.

·         Could Authors present a schematic mechanism of BPA degradation with use of PMS and PPB sample?

Concluding, I suggest a major revision of presented manuscript with perspective of acceptance after some corrections.

Author Response

Generally, presented manuscript entitled “Exploration of the catalytic activation capability of poplar wood powder waste pyrolyzed bio-char for organic pollutant degradation in water” is written with the very good English and the whole construction is concise and precise. However, some corrections, listed below, are needed.

 

1. In the Title, word “biochar” is written with dash, however later, without it. Please unify.

Ans: The authors thank the reviewer for careful reading. The mistyping has been revised.

 

2. Lines 36-37: “Due to the merits of room-temperature activation and rapid active radical generation rates [5]” – this sentence is somehow cut in the middle.

Ans: The authors feel sorry for the error. The sentence has been revised.

 

3. Among the text, there are many words incorrectly written with dash in the middle: “function-al”, “ana-lyze”, “con-tribute”, “degrada-tion” etc.

Ans: The authors thank the reviewer for careful reading. All the unnecessary dashed have been deleted.

 

 

4. Lines 50-51: “Meanwhile, few studies have explored the potential of introducing wood powder waste in fine processing and high added-value applications” - can Authors provide any citation?

Ans: This comment is appreciated. The references have been added for better understanding.

 

5. Lines 69-71: “[…] was calcined in a tubular furnace with a heating rate of 5°C/min under N2 atmosphere from room temperature to 200°C for 1h, and then heated to desired temperature, stayed at this temperature for 3h.” – if I understand correctly, the “room temperature -> 200°C” heating was a pretreatment. However, did it stayed at 200°C for 1h or the temperature increasing process lasted 1h?

Ans: The authors feel sorry for ambiguous expressions. The sentence has been revised for better understanding.

 

6. In some parts of the text (especially references) subscripts are missing.

Ans: The authors thank the reviewer for careful reading. The subscripts have been added.

 

7. Line 96: word “L-histidine” is written in italic, when in the rest of the text not. Please unify.

Ans: The authors thank the reviewer for careful reading. The typo has been revised.

 

 

8. Figure 1. Please add visible scale bars to the SEM pictures.

Ans: This comment is appreciated. The clearer scale bars have been inserted into the images

 

9. Lines 108-109: “The average particle size of obtained PPB sample became smaller with the increase of the pyrolysis temperature […]” – what are exact sizes of particles for all samples?

Ans: The authors thank the reviewer for careful reading. The approximated particle sizes have been added into the text.

 

10. Figure 2a: XRD of sample PPB-400 looks different than others. What is the possible reason? I also suggest using the same color for each sample on every Figure (e.g., PPB-400 – red, PPB-600 – blue, and so on). With this readers could compare results in easier way.

Ans: This comment is highly appreciated. Since wood powder contained many kinds of impurities including metal ions, nutrition compounds, pectins and metal compounds, the impurity peaks in PPB-400 might be the patterns of these compounds or derivatives. With the increase of the pyrolysis temperature, these impurities were also decomposed and/or gasified, resulting in the pure XRD patterns of PPB-600 and PPB-900.

The authors also thank the reviewer for the great suggestion of unifying the color of same sample. The color of Fig. 2a and 2b has been revised for better reading.

 

11. Line 150: I think word “declined” is not very accurate when describing decreasing of XPS peaks.

Ans: The authors thanks the reviewer for careful reading. The sentence has been revised for better understanding.

 

12. Could Authors present a schematic mechanism of BPA degradation with use of PMS and PPB sample?

Ans: This comment is highly appreciated. A schematic illustration of the BPA degradation mechanism in PPB/PMS system has been added into the text (Fig. 7(c)).

 

13. Concluding, I suggest a major revision of presented manuscript with perspective of acceptance after some corrections.

Ans: The manuscript has been carefully revised based on the reviewer’s comments. The authors thank the reviewer again for improving the quality of our study.

 

Reviewer 2 Report

1-      The novelty of the work must be clearer. Furthermore, the work must be compared with similar previous work, which was carried by similar material with focusing on the efficiency of this work in comparison with previous works

2-      In the SEM image, it was recommended to be supported with EDX analysis

3-      Please, insert the indices in the XRD diffractogram

4-      In figure 3, it is very low quality. I recommend using a color figure to simply detect the fitting

5-      Where is the mechanism of catalytic performance of our material

6-      Reason for decreasing the efficiency after repeating the catalytic test

 

7-      The gain results must be summarized and inserted in the abstract    

Author Response

1-The novelty of the work must be clearer. Furthermore, the work must be compared with similar previous work, which was carried by similar material with focusing on the efficiency of this work in comparison with previous works

Ans: The authors thank the reviewer for this comment. The novelty of this work has been added into the introduction part with sufficient supporting references. The performance comparison has also added into the text for better understanding.

 

2-In the SEM image, it was recommended to be supported with EDX analysis

Ans: The authors thank the reviewer for this comment. Since this study was finished about 1 year ago, EDX analysis for the same sample can not be conducted. While, the EDX analysis results would not influence the overall results and findings of this study. The authors will take the reviewer’s comment and conduct EDX analysis in the future studies.

 

3-Please, insert the indices in the XRD diffractogram

Ans: This comment is appreciated. The indices has been added into the XRD patterns

 

4-In figure 3, it is very low quality. I recommend using a color figure to simply detect the fitting

Ans: The authors thank the reviewer for improving the quality of our study. The XPS figures have been changed with colored curves.

 

5-Where is the mechanism of catalytic performance of our material

Ans: This comment is highly appreciated. The schematic illustration of BPA degradation mechanism in PPB/PMS system has been added into Fig. 7(c). Relevant discussion has been also added into the text.

 

6-Reason for decreasing the efficiency after repeating the catalytic test

Ans: The authors thank the reviewer for this comment. Since the functional groups (C=O) which could activated PMS were consumed during the BPA degradation process, the catalytic performance of PPB decreased after repeating the catalytic test. The relevant discussion has been added into the text for better understanding.

 

7- The gain results must be summarized and inserted in the abstract

Ans: The authors thank the reviewer for improving the quality of our study. The main results.

Reviewer 3 Report

The manuscript number (catalysts-1933818) elucidates the application of sulfate-based advanced oxidation process for removal of organic pollutant (Bisphenol A) via activation of peroxymonosulfate by biochar synthesized via a facile pyrolyzing poplar wood powder waste under different pyrolyzing temperatures. The prepared catalyst was characterized by several analytical techniques. The effect of some experimental parameters and reusability of the prepared catalysts on the removal efficiency were studied and discussed. The work is original and may attract some attention to the water treatment. In general, the objective of this study is suitable for publication in this journal and the topic is interesting. Therefore, I recommend this paper for publication after the following amendment.

My comments:

1. The title is unimpressive. I recommend the authors reconsider the title.

2. Experimental: For the analysis of pollutants examined in this study, HPLC should be used for the analysis, Please explain in the experimental section whether HPLC or spectrophotometric method was used.

3. Introduction needs updating with some references updating. Other advanced oxidation processes are also commonly used technologies for wastewater treatment. Key references:

https://doi.org/10.3390/coatings9080465

https://doi.org/10.1016/j.chemosphere.2019.04.160

4. Had the mineralization (TOC removal) been studied in this work?  

5. Error bars are missing in the figures. Some figures lake of detailed experimental conditions in the Figure caption. Please revise it.

 

6. Authors are recommended to revise the whole manuscript for language proof.

Author Response

The manuscript number (catalysts-1933818) elucidates the application of sulfate-based advanced oxidation process for removal of organic pollutant (Bisphenol A) via activation of peroxymonosulfate by biochar synthesized via a facile pyrolyzing poplar wood powder waste under different pyrolyzing temperatures. The prepared catalyst was characterized by several analytical techniques. The effect of some experimental parameters and reusability of the prepared catalysts on the removal efficiency were studied and discussed. The work is original and may attract some attention to the water treatment. In general, the objective of this study is suitable for publication in this journal and the topic is interesting. Therefore, I recommend this paper for publication after the following amendment.

My comments:

1. The title is unimpressive. I recommend the authors reconsider the title.

Ans: The authors thank the reviewer for this comment. The title has been revised.

 

2. Experimental: For the analysis of pollutants examined in this study, HPLC should be used for the analysis, Please explain in the experimental section whether HPLC or spectrophotometric method was used.

Ans: The authors fell sorry for missing the introduction of HPLC. The detailed experimental procedures have been added.

 

3. Introduction needs updating with some references updating. Other advanced oxidation processes are also commonly used technologies for wastewater treatment. Key references:

https://doi.org/10.3390/coatings9080465

https://doi.org/10.1016/j.chemosphere.2019.04.160

Ans: This comment is appreciated. The introduction part has been revised for better understanding. The mentioned references have also been added.

 

4. Had the mineralization (TOC removal) been studied in this work?

Ans: The authors thank the reviewer for this comment. The TOC removal test was conducted based on the reviewer’s suggestion, and the results with relevant discussion has been also added into the text.

 

5. Error bars are missing in the figures. Some figures lake of detailed experimental conditions in the Figure caption. Please revise it.

Ans: This comment is highly appreciated. The error bars for degradation experiments have been added into the figures. The figure captions have also been revised.

 

6. Authors are recommended to revise the whole manuscript for language proof.

Ans: The authors thank the reviewer for improving the quality of our study. The English of this manuscript has been carefully revised.

Round 2

Reviewer 1 Report

Authors answered all my questions and doubts as well as corrected the manuscript. In this regard, I suggest acceptance of presented paper in the revised form. 

Reviewer 2 Report

the paper can be accepted with this form

Reviewer 3 Report

The authors have revised the manuscript well according to the reviewers' comments. I think that the paper could be accepted for publication.