Catalytic Degradation of Organic Contaminants by Microwave-Assisted Persulfate Activation System: Performance and Mechanism

Round 1

Reviewer 1 Report

Review manuscript:

 Catalytic degradation of organic contaminants by micro- wave-assisted persulfate activation system: Performance and mechanism

 

The paper sound interesting, however there two major issues should be considered, determined, calculated and discussed:

1.     The rate order of the degradation reaction should be determined.

2.     The rate constant should be calculated and compared in all cases such as when changing reaction system: with or without: NiFe₂O₄ catalyst, persulfate, microwave power, pH….

3.     Minor issue

Other minor issue:

1.     The English should be checked again

2.     Some sentences needed to be written for example:

-         Line 61   transition mental elements oxide should be replaced by transition metal oxide

-         Line 51 page 2; what does MW/PMS refer to? Should it be MW/PS.

-         Line 139 page 4; sentence not clear:

phenol via using NiFe₂O₄/PS, systems reached degradation rates of, because PS only

 

 

 

 

Comments for author File: Comments.pdf

Author Response

Response to reviewer's comments

Journal Name: Catalysts

Ref. No.: catalysts-1935599

Manuscript Title: Catalytic degradation of organic contaminants by micro-wave- assisted persulfate activation system: Performance and mechanism

Corresponding Author: Xiuwen Cheng*

Co-authors: Yunhe Li, Weibao Liu, Lezhuo Li, Siyuan Jiang, Xiuwen Cheng*

 

Dear editors and anonymous reviewers,

We are very grateful for your precious comments and suggestions on our recently submitted manuscript (catalysts-1935599). We have considered carefully the editors and anonymous reviewers’ comments and submitted the response as a separate file. Meanwhile, we have revised the whole manuscript seriously including the English grammar and expressions. Both of the answers and revised sections were labeled with red color in the response file and revised manuscript. Our responses to the reviewers’ comments were listed point by point as followed.

Reviewer: The paper sound interesting, however there two major issues should be considered, determined, calculated and discussed:

1. The rate order of the degradation reaction should be determined.

Author reply:  Thanks for your careful reading and valuable comments. The rate order of degradation reaction is first order.

2. The rate constant should be calculated and compared in all cases such as when changing reaction system: with or without: NiFe₂O₄ catalyst, persulfate, microwave power, pH….

Author reply:  Thanks for your valuable suggestion. We have calculated he rate constant (Figure 3 and Figure 4).

Figure 3. Degradation of phenol in solution under various reaction system (a), PS concentration (b), catalyst dosage(c) and MW power(d) (Reaction conditions: PS concentration = 0.4 g/L, catalyst dosage = 0.6 g/L, phenol concentration = 0.01 g/L, reaction temperature= 25 °C and initial pH value = 6.5 (unadjusted))

Figure 4. Different reaction initial pH in the system of NiFe2O4 (a), the co-existing anions (b), TOC and toxicity analysis (c) and different inhibition experiments (d) (Reaction conditions: PS concentration = 0.4 g/L, catalyst dosage = 0.6 g/L, phenol concentration = 0.01 g/L, inhibition dosage =50 mmol, reaction temperature= 25°C and initial pH value = 6.5 (unadjusted))

 

3. The English should be checked again.

Author reply:  Thanks for your careful reading and valuable comments. The grammar and expression in whole manuscript were carefully revised. We hope that the correction will meet with approval.

4. Some sentences needed to be written for example:

-Line 61   transition mental elements oxide should be replaced by transition metal oxide

-Line 51 page 2; what does MW/PMS refer to? Should it be MW/PS.

-Line 139 page 4; sentence not clear:

phenol via using NiFe₂O₄/PS, systems reached degradation rates of, because PS only

Author reply:  Thank you for your suggestion. We have rewritten the sentences.

We have tried our best to improve the whole manuscript and made some changes in the revised manuscript. We appreciated for Editors and Reviewers’ warm work earnestly, and hoped that the correction could be approved by you. If you have any further questions on our manuscript, please do not hesitate to contact us. Once again, thank you very much for your comments and suggestions.

With best regards

Yours sincerely,

Prof. & Dr. Xiuwen Cheng

College of Earth and Environmental Sciences

Lanzhou University, Lanzhou 730000, P. R. China

E-mail: [email protected]

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

 

The manuscript entitled “Catalytic degradation of organic contaminants by micro-wave-assisted persulfate activation system: Performance and mechanism” is interesting to read. Although the concept is not new. Many authors already reported the phenol degradation by NiFe2O4, but ROS generation capture makes it interesting and there are some more suggestions to improve it. My suggestions are

1.     The authors are suggested to remove MW and PS from NiFe2O4/PS/MW as the microwave is not any material.

2.     Authors are advised to explain PMS before using it in complete manuscripts.

3.     TGA should be performed to check the stability of synthesized NiFe2O4.

4.     Thermodynamic considerations are needed in order to prove that generation of HO• and SO₄^2-• is possible in the band gap of NiFe2O4/PS/MW.

5.     Authors should use EPR to detect the generation of HO• and SO₄^2-•   for proof using Cayman DMPO in which big 4 peaks show the presence of HO• while small peaks like a noise show the presence of SO₄^2-•   is the generation of this is happening in absence of those small peaks only HO• is occurring. Therefore, this is a good test for checking specifically HO• and SO₄^2-•   radical generation

6.     Authors have not given a single reference for 2021 and 2022 which is very surprising as recent studies are a must.

 

7.     English improvements are needed

Author Response

Response to reviewer's comments

Journal Name: Catalysts

Ref. No.: catalysts-1935599

Manuscript Title: Catalytic degradation of organic contaminants by micro-wave- assisted persulfate activation system: Performance and mechanism

Corresponding Author: Xiuwen Cheng*

Co-authors: Yunhe Li, Weibao Liu, Lezhuo Li, Siyuan Jiang, Xiuwen Cheng*

 

Dear editors and anonymous reviewers,

We are very grateful for your precious comments and suggestions on our recently submitted manuscript (catalysts-1935599). We have considered carefully the editors and anonymous reviewers’ comments and submitted the response as a separate file. Meanwhile, we have revised the whole manuscript seriously including the English grammar and expressions. Both of the answers and revised sections were labeled with red color in the response file and revised manuscript. Our responses to the reviewers’ comments were listed point by point as followed.

Reviewer: The manuscript entitled “Catalytic degradation of organic contaminants by micro-wave-assisted persulfate activation system: Performance and mechanism” is interesting to read. Although the concept is not new. Many authors already reported the phenol degradation by NiFe₂O₄, but ROS generation capture makes it interesting and there are some more suggestions to improve it. My suggestions are

1. The authors are suggested to remove MW and PS from NiFe₂O₄/PS/MW as the microwave is not any material.

Author reply:  Thanks for your valuable comments. We have removed MW and PS from NiFe₂O₄/PS/MW.

2. Authors are advised to explain PMS before using it in complete manuscripts.

Author reply:  Thanks for your valuable suggestion. Your suggestion has taught us a lot.We have added the explanation about PS in the revised manuscript.

“PS can be seen as the product of the substitution of two hydrogen atoms in H₂O₂ by both sulfonyl-SO₃H. It is a white crystal and is very soluble in water. Figure 1 shows the PS structure.”

 

Figure 1. PS structural formula

3. TGA should be performed to check the stability of synthesized NiFe₂O₄.

Author reply:  Thank you for your suggestion. Regarding to the stability of the material, we have carried out reusability experiments. From the experimental results, we can see that after eight cycles, the removal rate of phenol can still be maintained at 96% (Figure. 6). It shows that the material has good stability.

4. Thermodynamic considerations are needed in order to prove that generation of HO• and SO₄^-• is possible in the band gap of NiFe₂O₄/PS/MW.

Author reply:  Thank you for your suggestion. Regarding the thermodynamic, we tested the removal effect of MW+PS system on phenol, and the removal rate could only reach 60%, while the removal rate of NiFe₂O₄/PS/MW system on phenol was 97.74%, indicating that the thermodynamic conditions produced some HO• and SO₄^-•, but more HO• and SO₄^-• were produced under NiFe₂O₄/PS/MW system.

5. Authors should use EPR to detect the generation of HO• and SO₄^-• for proof using Cayman DMPO in which big 4 peaks show the presence of HO• while small peaks like a noise show the presence of SO₄^-• is the generation of this is happening in absence of those small peaks only HO• is occurring. Therefore, this is a good test for checking specifically HO• and SO₄^-• radical generation.

Author reply:  Thank you for your suggestion. In this experiment, free radical quenching test is used to detect the production of HO• and SO₄^-•, which is also effective for the detection of two kinds of free radicals. For example, total et al. also used TBA and ethanol to determine the production of H and S in the FeCo-LDH/PMS system[1]. We will consider using EPR to detect the production of HO• and SO₄^-• in our subsequent experiments.

[1] Gong C, Chen F, Yang Q, et al., Heterogeneous activation of peroxymonosulfate by Fe-Co layered doubled hydroxide for efficient catalytic degradation of Rhoadmine B [J]. Chem. Eng. J., 2017, 321:222-232.

6. Authors have not given a single reference for 2021 and 2022 which is very surprising as recent studies are a must.

Author reply:  Thank you for your suggestion. In the manuscript, we have added the relevant literature in 2021 and 2022.

7. English improvements are needed.

Author reply:  Thanks for your careful reading and valuable comments. The grammar and expression in whole manuscript were carefully revised. We hope that the correction will meet with approval.

We have tried our best to improve the whole manuscript and made some changes in the revised manuscript. We appreciated for Editors and Reviewers’ warm work earnestly, and hoped that the correction could be approved by you. If you have any further questions on our manuscript, please do not hesitate to contact us. Once again, thank you very much for your comments and suggestions.

With best regards

Yours sincerely,

Prof. & Dr. Xiuwen Cheng

College of Earth and Environmental Sciences

Lanzhou University, Lanzhou 730000, P. R. China

E-mail: [email protected]

Author Response File: Author Response.pdf

Reviewer 3 Report

 

Comments to the Author

The authors reported an interesting work about “Catalytic degradation of organic contaminants by micro- 2 wave-assisted persulfate activation system: Performance and 3 mechanism”. The finding of this study will help to determine the most efficient and cost-effective method for removal of tetracycline. In all, this study is interesting and meaningful. It can be recommended to be published after revisions.

1.     In page 2, line 88,  the used solvent is wrong-check it carefully.

2.     Fig. 1C, the VSM graph should be plotted perfectly.

3.     The authors should calculate the average particle size from the XRD measurement.

4.     Author should discuss the VSM part with obtained results.

5.     Authors should include UV-Vis spectrum of optimized photocatalytic study.

6.     Authors should include Raman, UV-DRS and band gap measurement (TAUC plot) for the catalyst in the manuscript.

 

 

Author Response

Response to reviewer's comments

Journal Name: Catalysts

Ref. No.: catalysts-1935599

Manuscript Title: Catalytic degradation of organic contaminants by micro-wave- assisted persulfate activation system: Performance and mechanism

Corresponding Author: Xiuwen Cheng*

Co-authors: Yunhe Li, Weibao Liu, Lezhuo Li, Siyuan Jiang, Xiuwen Cheng*

 

Dear editors and anonymous reviewers,

We are very grateful for your precious comments and suggestions on our recently submitted manuscript (catalysts-1935599). We have considered carefully the editors and anonymous reviewers’ comments and submitted the response as a separate file. Meanwhile, we have revised the whole manuscript seriously including the English grammar and expressions. Both of the answers and revised sections were labeled with red color in the response file and revised manuscript. Our responses to the reviewers’ comments were listed point by point as followed.

Reviewer: The authors reported an interesting work about “Catalytic degradation of organic contaminants by micro-wave-assisted persulfate activation system: Performance and mechanism”. The finding of this study will help to determine the most efficient and cost-effective method for removal of tetracycline. In all, this study is interesting and meaningful. It can be recommended to be published after revisions.

1. In page 2, line 88, the used solvent is wrong-check it carefully.

Author reply:  Thanks for your careful reading and valuable comments. The used solvent in whole manuscript were carefully revised.

2. Fig. 1C, the VSM graph should be plotted perfectly.

Author reply:  Thanks for your valuable suggestion. We have redrawn the VSM graph.

3. The authors should calculate the average particle size from the XRD measurement.

Author reply:  Thank you for your suggestion. We have calculated the average particle size from the XRD measurement. “It is calculated that the average particle size of NiFe₂O₄ is 15.17nm.”

4. Author should discuss the VSM part with obtained results.

Author reply:  Thank you for your suggestion. We have added the discussion of the VSM part with obtained results. “The magnetization curve revealed a typical S-shaped with the external magnetic field, indicating that NiFe₂O₄ is a ferromagnetic material [24].”

5. Authors should include UV-Vis spectrum of optimized photocatalytic study.

Author reply:  Thank you for your suggestion. In this manuscript, we focused on microwave activation of NiFe₂O₄ in the presence of persulfate. After carefully consideration, we did not add the UV-Vis spectrum. In the future study, we would like to measure the photocatalytic performance.

6. Authors should include Raman, UV-DRS and band gap measurement (TAUC plot) for the catalyst in the manuscript.

Author reply:  Thank you for your suggestion. In this manuscript, we focused on microwave activation of NiFe₂O₄ in the presence of persulfate. After carefully consideration, we did not add the Raman and UV-Vis spectrum. In the future study, we would like to measure the photocatalytic performance.

We have tried our best to improve the whole manuscript and made some changes in the revised manuscript. We appreciated for Editors and Reviewers’ warm work earnestly, and hoped that the correction could be approved by you. If you have any further questions on our manuscript, please do not hesitate to contact us. Once again, thank you very much for your comments and suggestions.

With best regards

Yours sincerely,

Prof. & Dr. Xiuwen Cheng

College of Earth and Environmental Sciences

Lanzhou University, Lanzhou 730000, P. R. China

E-mail: [email protected]

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The paper can be accepted

Author Response

Thanks for your approval of our manuscript.

Reviewer 2 Report

Tha author did not fullfill maximum comments raised by reviewer. I suggest the authors ato understand the difference between thermal analysis of materials and and regeneration experiment of catalyst. This is the one example. There are many other. Therefore, this manuscript can not be accepted in this form. However,  I would like to reconsider the manuscript if author can address at least some of the comments.

Author Response

Response to reviewer's comments

Journal Name: Catalysts

Ref. No.: catalysts-1935599

Manuscript Title: Catalytic degradation of organic contaminants by micro-wave- assisted persulfate activation system: Performance and mechanism

Corresponding Author: Xiuwen Cheng*

Co-authors: Yunhe Li, Weibao Liu, Lezhuo Li, Siyuan Jiang, Xiuwen Cheng*

 

Dear editors and anonymous reviewers,

We are very grateful for your precious comments and suggestions on our recently submitted manuscript (catalysts-1935599). We have considered carefully the editors and anonymous reviewers’ comments and submitted the response as a separate file. Meanwhile, we have revised the whole manuscript seriously including the English grammar and expressions. Both of the answers and revised sections were labeled with red color in the response file and revised manuscript. Our responses to the reviewers’ comments were listed point by point as followed.

Reviewer: The author did not fulfill maximum comments raised by reviewer. I suggest the authors ato understand the difference between thermal analysis of materials and regeneration experiment of catalyst. This is the one example. There are many other. Therefore, this manuscript cannot be accepted in this form. However, I would like to reconsider the manuscript if author can address at least some of the comments.

Author reply:  Thanks for your careful reading and valuable comments. We have added thermal analysis of the material, as shown in Figure 7. “The thermal analysis (Figure 7) shows that there is no weight change in the temperature range of 0-1000 ℃, which proves the stability of the material.” In our future study, we will carry out other stability measurements.

Figure 7. TGA curves of the NiFe₂O₄

We have tried our best to improve the whole manuscript and made some changes in the revised manuscript. We appreciated for Editors and Reviewers’ warm work earnestly, and hoped that the correction could be approved by you. If you have any further questions on our manuscript, please do not hesitate to contact us. Once again, thank you very much for your comments and suggestions.

With best regards

Yours sincerely,

Prof. & Dr. Xiuwen Cheng

College of Earth and Environmental Sciences

Lanzhou University, Lanzhou 730000, P. R. China

E-mail: [email protected]

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors have performed the revisions in a perfect manner. Now this manuscript can be accepted  for publication

Author Response

Thanks for your approval of our manuscript.