Pulsed Discharge Plasma in High-Pressure Environment for Water Pollutant Degradation and Nanoparticle Synthesis
Round 1
Reviewer 1 Report
This manuscript dealt with variety of carbon and TiO2 NPs preparation using plasma technique. It is an interesting field of research. The results are explained in detail and at the same time some deviation from the scope of the research is found which can be corrected. It needs a minor revision, some of the critical comments are given below.
1.Line 55-57: State clearly whether the plasma was generated over the liquid surface , similar to the jet plasma type.
2.Line 58: due to its inert and non-polluting nature
3.In introduction, the merits of utilization of Ar gas was mentioned in detail whereas the plasma decomposition of dyes and nanoparticle generation was not given enough.
4.There are list of amino acids were given as a media. But exact precursors with its concentration or procedure for formation of nanoparticles was not given. In addition, state briefly the mechanism of formation of nanoparticles. Why amino acids were chosen for preparing carbon materials (is it possible from simple carbohydrates)?. Similar to aminoacids, you might use any titanium precursor, instead of metal corrosion.
5.Mention the applied voltage, power and gas flow rates used for nanoparticle generation and dye decomposition.
6.Is it possible to predict the species density by increasing or decreasing the plasma power and the spectroscopic methods?.
7.Line 305: what it the metal rod in SUS reactor?.
8.The discharge number units are in pulses/sec or pulses/min in fig. 5?.
9.Line 364: Usually the radicals are responsible for dye decolouration rather than electrons, confirm it again.
10.The pyrrole polymerization process is something a deviation from the present research title.
11.Mention the quantity, plasma exposure duration, solution concentration etc used for carbon materials preparation as in fig. 8.
12.In fig. 11, did you observe any nanotubes formation?
Author Response
Reviewer 1.
Comments and Suggestions for Authors: This manuscript dealt with variety of carbon and TiO2 NPs preparation using plasma technique. It is an interesting field of research. The results are explained in detail and at the same time some deviation from the scope of the research is found which can be corrected. It needs a minor revision, some of the critical comments are given below.
Answer: Thank you very much for your kind suggestion.
Comment 1: Line 55-57: State clearly whether the plasma was generated over the liquid surface, similar to the jet plasma type.
Answer: Thank you very much for your good comment. Yes, it seems similar to plasma jet but the argon gas was not flowed. The experiment was performed in batch process. We have explained it, please see in “Introduction” section (page 2 line 55).
Comment 2: Line 58: due to its inert and non-polluting nature
Answer: Thank you very much for your pointing out this. We have revised it, please see in “Introduction” section (page 2 line 57).
Comment 3: In introduction, the merits of utilization of Ar gas was mentioned in detail whereas the plasma decomposition of dyes and nanoparticle generation was not given enough.
Answer: Thank you very much for your good recommendation. We have added some explanation and some references. Please see in “Introduction” section (page 2 line 87 and page 3 line 107).
Comment 4: There are list of amino acids were given as a media. But exact precursors with its concentration or procedure for formation of nanoparticles was not given. In addition, state briefly the mechanism of formation of nanoparticles. Why amino acids were chosen for preparing carbon materials (is it possible from simple carbohydrates)?. Similar to aminoacids, you might use any titanium precursor, instead of metal corrosion.
Answer: Thank you very much for your good questions. Yes, other chemical compounds or precursors can be used. We have added some explanation why amino acids were chosen. Please see in “Results and Discussion” section (page 10 lines 515 and 524 and page 13 line 672).
Comment 5: Mention the applied voltage, power and gas flow rates used for nanoparticle generation and dye decomposition.
Answer: Thank you very much for your good recommendation. In this work, the experiment was performed in batch process, hence the argon gas was not flowed. We have added some explanation. Please see in “Materials and Methods” section (page 3 line 141 and page 4 line 150) and “Results and Discussion” section (page 7 line 348 and page 10 line 518).
Comment 6: Is it possible to predict the species density by increasing or decreasing the plasma power and the spectroscopic methods?.
Answer: Thank you very much for your good question. Yes, perhaps, it is possible to determine them (Engeln et al. Plasma Sources Sci. Technol. 2020, 29, 063001).
Comment 7: Line 305: what it the metal rod in SUS reactor?.
Answer: Thank you very much for your good question. We have added some explanation. Please see in “Results and Discussion” section (page 7 line 345).
Comment 8: The discharge number units are in pulses/sec or pulses/min in fig. 5?.
Answer: Thank you very much for your pointing out this. We have revised it. Please see in Figure 5.
Comment 9: Line 364: Usually the radicals are responsible for dye decolouration rather than electrons, confirm it again.
Answer: Thank you very much for your good comment. We have added some explanation. Please see in “Results and Discussion” section (page 8 line 402).
Comment 10: The pyrrole polymerization process is something a deviation from the present research title.
Answer: Thank you very much for your good comment. We have added some explanation. Please see in “Results and Discussion” section (page 8 line 412).
Comment 11: Mention the quantity, plasma exposure duration, solution concentration etc used for carbon materials preparation as in fig. 8.
Answer: Thank you very much for your good recommendation. We have added some explanation. Please see in “Results and Discussion” section (page 10 line 517).
Comment 12: In fig. 11, did you observe any nanotubes formation?
Answer: Thank you very much for your good question., However, we did not observe it.
Reviewer 2 Report
The authors have presented an experimental study on electrical discharges in contact with water and studying some fundamental properties as well as applied ones.
The main issue with the paper is its generality. Indeed, one can find imaging, optical emission characterization, decoloration study, nanoparticles, mechanism pathway, etc. Each subject can be considered as paper if thourougly analyzed and presented. In this context, my suggestion is to reject this paper. Resubmission may be considered if the authors reorganize the paper while focusing on a specific subject. Mixing everything makes the paper uncomprehensive and less important for readers.
Author Response
Comments and Suggestions for Authors: The authors have presented an experimental study on electrical discharges in contact with water and studying some fundamental properties as well as applied ones. The main issue with the paper is its generality. Indeed, one can find imaging, optical emission characterization, decoloration study, nanoparticles, mechanism pathway, etc. Each subject can be considered as paper if thourougly analyzed and presented. In this context, my suggestion is to reject this paper. Resubmission may be considered if the authors reorganize the paper while focusing on a specific subject. Mixing everything makes the paper uncomprehensive and less important for readers.
Answer: Thank you very much for your good comment. We have added some explanation and some references to improve the manuscript.
Reviewer 3 Report
The paper is very well written, and the results presented correlate well with the proposed outcome. The paper can be accepted with some minor revisions.
- Please explain in the introduction sections why the authors chose Argon and not Helium as the discharge gas in the liquid medium. It would be beneficial to understand the benefits of Argon gas over Helium for such applications.
- In figure 4, there are prominent peaks that are not labelled in the wavelength ranging from 250 to 500 nm. Please provide a detailed explanation of the peaks. OH radical is usually around 309-311 nm. How is it distinguishable from the other small peak the that the authors have labelled for OH, provided in the inset of figure 4?
- Please provide future work in the conclusion section. Are there no other improvements than can be done over this method? Future work from this project should not only identify the drawbacks but help understand some improvement that can be done from this experiment.
Author Response
Comments and Suggestions for Authors: The paper is very well written, and the results presented correlate well with the proposed outcome. The paper can be accepted with some minor revisions.
Answer: Thank you very much for your kind suggestion.
Comment 1: Please explain in the introduction sections why the authors chose Argon and not Helium as the discharge gas in the liquid medium. It would be beneficial to understand the benefits of Argon gas over Helium for such applications.
Answer: Thank you very much for your good recommendation. We have added some explanation and some references. Please see in “Introduction” section (page 2 line 57).
Comment 2: In figure 4, there are prominent peaks that are not labelled in the wavelength ranging from 250 to 500 nm. Please provide a detailed explanation of the peaks. OH radical is usually around 309-311 nm. How is it distinguishable from the other small peak the that the authors have labelled for OH, provided in the inset of figure 4?
Answer: Thank you very much for your good comment. We have revised this part. Please see in “Results and Discussion” section (Figure 4).
Comment 3: Please provide future work in the conclusion section. Are there no other improvements than can be done over this method? Future work from this project should not only identify the drawbacks but help understand some improvement that can be done from this experiment.
Answer: Thank you very much for your good recommendation. We have revised it and added some explanation. Please see in “Conclusion and Future Directions”.
Round 2
Reviewer 2 Report
Although there are no significant changes in paper structure, and it shows surface investifation of the multiple subjects, it may be accepted.
