Shining a Light on Sewage Treatment: Building a High-Activity and Long-Lasting Photocatalytic Reactor with the Elegance of a “Kongming Lantern”

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

After thoroughly examining your manuscript, I would like to express my positive feedback regarding your submission. Your study is of interest to the readers of Catalysts journal. However, I believe there is room for improvement, and I would like to request some revisions based on the following remarks:

- I really like your figures, but some of them contain too many subfigures, often presenting different aspects. I understand the need to reduce the number of figures, but I believe it would be beneficial to present some of the subfigures as individual figures. Specifically, I am referring to the following: Figure 2f should be presented as a separate figure, as well as the subfigures from Figure 5. Additionally, Figure 5 lacks an explanation for subfigure c. The same applies to Figure 6.

- Occasionally, there is a missing space between the word and the citation.

- In the Introduction, it is necessary to provide a more comprehensive background on the application of polymers in photocatalysis. Including references to the most recent papers would also be beneficial.

- The font size within Figure 5b should be increased.

- The dots in Figures 6d and 6e appear too pale. Please make them clearer.

Upon addressing all of the aforementioned comments, I would be pleased to review your manuscript again.

Best regards

Author Response

Dear reviewer, 

We feel great thanks for your professional review work on our article. As you are concerned, there are several problems that need to be addressed.According to your nice suggestions, we have made extensive corrections to our previous draft, the detailed corrections are listed below.

Comments 1: [ I really like your figures, but some of them contain too many subfigures, often presenting different aspects. I understand the need to reduce the number of figures, but I believe it would be beneficial to present some of the subfigures as individual figures. Specifically, I am referring to the following: Figure 2f should be presented as a separate figure, as well as the subfigures from Figure 5. Additionally, Figure 5 lacks an explanation for subfigure c. The same applies to Figure 6.]

Response 1: We sincerely thank the reviewer for careful reading and commending. We were really sorry for our careless mistakes.  As suggested by the reviewer, we have corrected the combination of figures. However, Figure 6 (previously Figure 5) may not have explained its subgraphs clearly before, resulting in some incongruity among the combinations of subgraphs. Now that the explanations of each subgraph have been added, does it need to be reassembled?

Moreover, explanations of the subfigure in Figures 6 and 7 are added to the text. These revised parts are marked in red in the manuscript included pages 5, 6 and 9. Thank you for your reminder. 

Comments 2: [Occasionally, there is a missing space between the word and the citation.]

Response 2: We feel sorry for our carelessness. In our resubmitted manuscript, the type is revised and marked in red in the manuscript. Thanks for your correction. 

Comments 3: [In the Introduction, it is necessary to provide a more comprehensive background on the application of polymers in photocatalysis. Including references to the most recent papers would also be beneficial.]

Response 3: We sincerely appreciate the valuable comments. We have checked the literature carefully and added more references on the different load preparation methods of photocatalysts and the application of 3D printing technology in photocatalytic reactorsinto the INTRODUCTION part in the revised manuscript. Revised parts are marked in red in the manuscript included pages 2 and 3.

Comments 4: [The font size within Figure 5b should be increased.]

Response 4: We sincerely appreciate the valuable comments. We think this is an excellent suggestion. We have adjusted the size within Figure 6b and the revised figure can be found in the page 9.

Comments 5: [The dots in Figures 6d and 6e appear too pale. Please make them clearer.]

Response 5: We sincerely appreciate the valuable comments. We think this is an excellent suggestion. We have adjusted the size within Figure 7d and 7e and the revised figure can be found in the page 9.

In a word, we sincerely thank the editor and all reviewers for their valuable feedback that we have used to improve the quality of our manuscript. We hope the above reply is to your satisfaction and look forward to receive comments from the reviewers. If you have any queries, please do not hesitate to contact me.

Yours sincerely,
Prof. Yi Wang

Reviewer 2 Report

Comments and Suggestions for Authors

1. To confirm the fact of effective photocatalytic destruction of dyes, the results (or their description) of a zero experiment are necessary. That is, with pure photolysis, without the introduction of a catalyst.

Please see the attachment.

 

Comments for author File: Comments.pdf

Author Response

Dear reviewer, 

We feel great thanks for your professional review work on our article. As you are concerned, there are several problems that need to be addressed.According to your nice suggestions, we have made extensive corrections to our previous draft, the detailed corrections are listed below.

Comments 1: [in the opinion of the reviewer, it is possible to additionally indicate (if any) existing analoguesof photocatalysts and similar technologies.]

Response 1: We sincerely appreciate the valuable comments. We have checked the literature carefully and added more references on the different load preparation methods of photocatalysts and the application of 3D printing technology in photocatalytic reactorsinto the INTRODUCTION part in the revised manuscript. Revised parts are marked in red in the manuscript included pages 2 and 3.

Comments 2: [the pH ranges at which they worked are not specified. It should be specified.]

Response 2: We sincerely appreciate the valuable comments. We think this is an excellent suggestion. We have added a description of the pH of the solution to the text and marked in red in the manuscript included pages 11 and 12.

Comments 3: [figure 3 shows the results of the photocatalytic oxidation of dyes. It should be supplemented in the text what the oxidation efficiency was with pure photolysis, without the introduction of a catalyst.]

Response 3: We sincerely appreciate the valuable comments. We think this is an excellent suggestion. We have supplemented the experimental results of this part and added the experimental results to the figure on page 7, and the relevant words are explained in the red part on page 6.

In a word, we sincerely thank the editor and all reviewers for their valuable feedback that we have used to improve the quality of our manuscript. We hope the above reply is to your satisfaction and look forward to receive comments from the reviewers. If you have any queries, please do not hesitate to contact me.

Yours sincerely,
Prof. Yi Wang

Reviewer 3 Report

Comments and Suggestions for Authors

3D printing technology is utilized to construct a photocatalytic reactor resembling a "Kongming Lantern," guaranteeing both high activity and durability. The reactor exhibited remarkable performance in degrading organic dyes and eliminating microbes, and displayed a satisfactory purification effect on real water samples. The manuscript is suitable for publication. Some minor remarks see below:

1. Could the designe reactor  eliminated the temperature effects? 

2. The separation of photoinduced chemistry from therma process is very important. In certain case differnt paths exist in two process, see for example: CATALYSIS LETTERS 149 : 6 pp. 1441-1454. , 14 p. (2019)

3. Is there possibility to chek the photoprocess without catalyst samle?

 

Author Response

Dear reviewer, 

We feel great thanks for your professional review work on our article. As you are concerned, there are several problems that need to be addressed.According to your nice suggestions, we have made extensive corrections to our previous draft, the detailed corrections are listed below.

Comments 1: [Could the designe reactor  eliminated the temperature effects? ]

Response 1: We feel sorry for our carelessness. In our previous manuscript, the description of this part was neglected. Thank you for your reminding. We have added a description of this section in the manuscript and in Figure 9. Yes, as you asked, we took the temperature into account at the very beginning of building the reactor. The specific performance is that a large amount of ice is used in another container outside the constructed reaction tank to absorb and eliminate the heat released during the reaction process, so as to reduce the influence of the thermal process on the photocatalytic reaction. Thank you again for your valuable reminder.

Comments 2: [The separation of photoinduced chemistry from therma process is very important. In certain case differnt paths exist in two process, see for example: CATALYSIS LETTERS 149 : 6 pp. 1441-1454. , 14 p. (2019)]

Response 2: We sincerely appreciate the valuable comments. We have checked the literature you suggested carefully and added it in the revised manuscript on page 12.

Comments 3: [Is there possibility to chek the photoprocess without catalyst samle?]

Response 3: We sincerely appreciate the valuable comments. We think this is an excellent suggestion. We have supplemented the experimental results of this part and added the experimental results to the figure on page 7, and the relevant words are explained in the red part on page 6.

In a word, we sincerely thank the editor and all reviewers for their valuable feedback that we have used to improve the quality of our manuscript. We hope the above reply is to your satisfaction and look forward to receive comments from the reviewers. If you have any queries, please do not hesitate to contact me.

Yours sincerely,

Prof. Yi Wang

Reviewer 4 Report

Comments and Suggestions for Authors

The presented work is devoted to the development and research of the efficiency of photocatalytic reactors used for wastewater treatment of various types. The authors propose a new approach in both the creation of photocatalysts and in the design of reactors. It is shown that the use of 3-d printing for applying a photocatalytic layer to a substrate makes it possible to create highly effective and externally resistant catalysts. The presented work is the first stage in this study and has great prospects for further development.

However, there are a number of questions about the work:

1. In the text of the article, it is necessary to provide a transcript of samples I, II, III and IV, presented in Fig. 1. What stages of preparation does the sample go through?

2. Is there any justification for choosing the concentration of dyes in the solution?

3. The authors claim the "outstanding efficiency" of the decomposition of dyes, but this is not confirmed by any comparative estimates with the works of other authors. It should be noted that even with a decomposition efficiency of 99.66%, 0.034 mg/l of dye will remain in the solution, and this concentration may be toxic to living organisms in natural waters. There is no analysis of the resulting decomposition products, which can also be toxic. Therefore, the indicator of the degree of decomposition of the initial compound cannot generally characterize the effectiveness of the process under study.

4. The article says that Figure 6. (c) shows the "image of the SEM after cleaning", however, this figure shows the dynamics of degradation.

5. The method of applying the photocatalyst to the substrate (Figure 7) would be more convenient to present in stages and each stage in Fig. indicate with a number. For example, stage 1: the bio powder is finely ground to ensure the absence of large particles, etc. It was easier for the readers of the article.

6. It is advisable to provide a description of the light source used (the spectral characteristic or at least the maximum wavelength). 

7. In the methodological part, it is necessary to specify: a) what volume of solution was placed in the reactor; b) the size of the gap (the length of the radiation path) between the radiation source and the photocatalyst; c) was the solution mixed in the reactor? This is necessary because these indicators affect the efficiency of the decomposition process.

8. The article states that Figure 8 (c) shows the "Front view of the device assembly", however, a cylindrical container is shown under (c). 

Author Response

Dear reviewer, 

We feel great thanks for your professional review work on our article. As you are concerned, there are several problems that need to be addressed.According to your nice suggestions, we have made extensive corrections to our previous draft, the detailed corrections are listed below.

Comments 1: [In the text of the article, it is necessary to provide a transcript of samples I, II, III and IV, presented in Fig. 1. What stages of preparation does the sample go through?]

Response 1: We sincerely appreciate the valuable comments. We think this is an excellent suggestion. We have re-written this part according to the Reviewer's suggestion. Revised parts are marked in red in the manuscript on page 3.

Comments 2: [Is there any justification for choosing the concentration of dyes in the solution?]

Response 2: We feel great thanks for your professional review work on our article. In the selection of concentrations in solution, on the one hand, reference was made to the previous work of the research group, and on the other hand, it is particularly important to refer to some of the high-level articles published so far, which are also mentioned in the revised manuscript (the revised part is highlighted in red on page 12). In view of the above two aspects, and considering the size of the reactor and the capacity of the reaction pool, we chose 60mL and 10mg/L as the choices.

Comments 3: [The authors claim the "outstanding efficiency" of the decomposition of dyes, but this is not confirmed by any comparative estimates with the works of other authors. It should be noted that even with a decomposition efficiency of 99.66%, 0.034 mg/l of dye will remain in the solution, and this concentration may be toxic to living organisms in natural waters. There is no analysis of the resulting decomposition products, which can also be toxic. Therefore, the indicator of the degree of decomposition of the initial compound cannot generally characterize the effectiveness of the process under study.]

Response 3: We sincerely appreciate the valuable comments. In our previous manuscript, we did not give a detailed summary of the articles on photocatalytic degradation of dyes that have been reported so far. We are very sorry. After this revision, we have checked the literature carefully and added more references on the different load preparation methods of photocatalysts and the application of 3D printing technology in photocatalytic reactorsinto the INTRODUCTION part in the revised manuscript. Revised parts are marked in red in the manuscript included pages 2 and 3.

In the article discussed, some excellent work related to dyestuff degradation performance, although in their description, they used photocatalytic degradation of dyestuff also achieved excellent results, but on the one hand, there are few similar work reports mentioned that the degradation effect reached 100%, on the other hand, their "excellent" is still far from our work. Thus we claim the "superior efficiency" of dye decomposition. We are also very grateful to the reviewers for their detailed reading and evaluation of our work, which will benefit us greatly in our future work.

Comments 4: [The article says that Figure 6. (c) shows the "image of the SEM after cleaning", however, this figure shows the dynamics of degradation.]

Response 4: We sincerely thank the reviewer for careful reading. We are sorry for our carelessness. Based on your comments, we have made the corrections to make the description harmonized within the image.

Comments 5: [The method of applying the photocatalyst to the substrate (Figure 7) would be more convenient to present in stages and each stage in Fig. indicate with a number. For example, stage 1: the bio powder is finely ground to ensure the absence of large particles, etc. It was easier for the readers of the article.]

Response 5: We sincerely appreciate the valuable comments. We think this is an excellent suggestion. We have re-written this part according to the Reviewer's suggestion. Revised parts are marked in red in the manuscript on page 10.

Comments 6: [It is advisable to provide a description of the light source used (the spectral characteristic or at least the maximum wavelength). ]

Response 6: We feel sorry for our carelessness. In our previous manuscript, the description of this part was neglected. Thank you for your reminding. We have added a description of this section in the manuscript and in Figure 11 (revised parts are marked in red).  Thank you again for your valuable reminder.

Comments 7: [ In the methodological part, it is necessary to specify: a) what volume of solution was placed in the reactor; b) the size of the gap (the length of the radiation path) between the radiation source and the photocatalyst; c) was the solution mixed in the reactor? This is necessary because these indicators affect the efficiency of the decomposition process.]

Response 7: We sincerely thank the reviewer for careful reading. Thank you for your reminder. We have checked the manuscript carefully and added these important information in the Methodological part. Revised parts are marked in red in the manuscript on page 11 and 12.

Comments 8: [The article states that Figure 8 (c) shows the "Front view of the device assembly", however, a cylindrical container is shown under (c). ]

Response 8: We sincerely thank the reviewer for careful reading. We are sorry for our carelessness. Based on your comments, we have made the corrections to make the description harmonized within the image.

In a word, we sincerely thank the editor and all reviewers for their valuable feedback that we have used to improve the quality of our manuscript. We hope the above reply is to your satisfaction and look forward to receive comments from the reviewers. If you have any queries, please do not hesitate to contact me.

Yours sincerely,

Prof. Yi Wang