Photosensitization of TiO₂ with Copper for the Photodegradation of Organic Contaminants in Water

Round 1

Reviewer 1 Report (Previous Reviewer 1)

Comments and Suggestions for Authors

The manuscript in its current form is still inappropriate for publication for several reasons:

• The authors should describe the degradation % of the organic pollutants.
• Need to add XRD and SEM images of TiO2.

Author Response

The authors appreciate the comments from the reviewers on our manuscript entitled "Photosensitization of TiO₂ with copper for the photodegradation of organic pollutants in water ". These comments They were very helpful and effectively helped improve the manuscript. We have read each of the comments and have made corrections to each of them. The revisions in the paper are shown highlighted in yellow. The main corrections in the paper and the responses to the reviewers' comments are mad individually:

 

Reviewer # 1

Comments

 

The manuscript in its current form is still inappropriate for publication for several reasons:

 

• The authors should describe the degradation % of the organic pollutants.

The degradation of organic contaminants in water is verified through laboratory analysis, the results of which are shown in Table 1, and the phenomenon through which this occurs is presented in the results discussion session.

 

• Need to add XRD and SEM images of TiO₂.

XRD patterns and images of pure TiO₂ powders and those doped with copper are presented.

 

Reviewer 2 Report (Previous Reviewer 3)

Comments and Suggestions for Authors

1. The authors have not responded to the essence of remark N11. To determine the position of copper in the structure of the sample, it is necessary to perform XPS studies.
2. The authors have not responded to the essence of remark N12. It does not follow from the X-ray diffraction data that copper is in the Cu2+ state. It does not follow from Fig. 6 either. It is necessary to conduct EPR and XPS studies. 
3. It is necessary to add XRD spectrum for pure TiO2 to Figure 3. It is necessary to make sure that pure TiO2 does not contain copper as a non-controllable impurity.
4. The authors have not responded to the essence of remark N13. It is necessary to conduct EPR and XPS studies.

Author Response

The authors appreciate the comments from the reviewers on our manuscript entitled "Photosensitization of TiO₂ with copper for the photodegradation of organic pollutants in water ". These comments They were very helpful and effectively helped improve the manuscript. We have read each of the comments and have made corrections to each of them. The revisions in the paper are shown highlighted in yellow. The main corrections in the paper and the responses to the reviewers' comments are mad individually:

 

Reviewer # 2

Comments

 

1. The authors have not responded to the essence of remark N11. To determine the position of copper in the structure of the sample, it is necessary to perform XPS studies.

Unfortunately, there is no access to equipment to perform XPS studies. However, evidence of the existence of copper is presented through the XRD patterns of TiO₂ powder and the TiO₂/Cu mixture. Likewise, through the absorbance curves presented separately for water treatment with and without the presence of copper.

 

2. The authors have not responded to the essence of remark N12. It does not follow from the X-ray diffraction data that copper is in the Cu²⁺ It does not follow from Fig. 6 either. It is necessary to conduct EPR and XPS studies.

Same comment as question 1, unfortunately we do not have access to EPR and XPS studies. But evidence is presented that copper is causing the phenomenon of photosensitization, and an attempt is made to explain the phenomenon.

 

3. It is necessary to add XRD spectrum for pure TiO₂ to Figure 3. It is necessary to make sure that pure TiO₂ does not contain copper as a non-controllable impurity.

A XRD study of pure TiO₂ is presented.

 

4. The authors have not responded to the essence of remark N13. It is necessary to conduct EPR and XPS studies.

Same comment as question 1, unfortunately we do not have access to EPR and XPS studies. But evidence is presented that copper is causing the phenomenon of photosensitization, and an attempt is made to explain the phenomenon.

 

 

Reviewer 3 Report (Previous Reviewer 4)

Comments and Suggestions for Authors

Dear Authors,

I have looked at your reviewed Manuscript titled: ” Photosensitization of TiO₂ with copper for the photodegradation of organic pollutants in water”. Since all suggestions have been implemented, I suggest that this paper should be published in the journal Powders.

With my kindest regards,

Author Response

The authors appreciate the comments from the reviewers on our manuscript entitled "Photosensitization of TiO₂ with copper for the photodegradation of organic pollutants in water ". These comments They were very helpful and effectively helped improve the manuscript. We have read each of the comments and have made corrections to each of them. The revisions in the paper are shown highlighted in yellow. The main corrections in the paper and the responses to the reviewers' comments are mad individually:

 

Reviewer # 3

Comments

 

1. I have looked at your reviewed Manuscript titled: “Photosensitization of TiO₂ with copper for the photodegradation of organic pollutants in water”. Since all suggestions have been implemented, I suggest that this paper should be published in the journal Powders.

This referee finds the manuscript suitable. Even so, it was improved by adding more experimental evidence according to what was requested by referees 1, 2 and even the editor.

Round 2

Reviewer 1 Report (Previous Reviewer 1)

Comments and Suggestions for Authors

This revision has improved the manuscript.

Comments on the Quality of English Language

The authors should spell-check the manuscript thoroughly to eliminate grammatical errors.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Title of the paper: Photosensitization of TiO2 with copper for the photodegradation of organic pollutants in water.

Comments: The manuscript in its current form is inappropriate for publication for several reasons:

• What are the novel aspects of the work?
• Preparation is the process of mixing ready-made materials.
• The article has been described based on the literature. There is some discussion that has no experimental evidence.
• There are shortcomings regarding the writing methodology and characterization study.
• There are issues related to the application.

Comments on the Quality of English Language

The authors should spell-check the manuscript thoroughly to eliminate grammatical errors.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript is an excellent first draft for publication, but it requires additional experiments to confirm the conclusions.

• There are no controls for the experiment.
• There are no replicates.
• There are no statistics to compare the differences.
• How do the authors know that the decrease of the absorbance is by photodegradation (figures 5 and 6) instead of adsorption?
• What instrument was used to determine the size of the powders? (Page 3, line 108).
• When the authors mention the powder size, are they referring to TiO₂ or the mix?
• SEM analysis only shows the TiO₂ structure. How do the authors know that the Cu NPs doped the TiO₂? Additionally, there is no explanation provided in the XRD analysis regarding the effect of Cu-doping on TiO₂.
• If the authors bought a TiO₂ of 5 um (Page 2, line 80), how does the XRD analysis suggest nanocrystals of 5.62 nm (Page 4, line 135)?
• Sunlight irradiation (Page 4, line 147): what are the parameters???
• The methodology needs to be described in more detail.
• In the discussion, the authors mention a shift in absorption to the light region due to the dopant effect, but there are no results about it.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors' work is devoted to a very important and relevant topic - wastewater treatment from toxic impurities. For several decades, scientists have been trying to create an energy-efficient device for wastewater treatment, but so far the situation is limited to laboratory samples. This article needs major revision, since it has many shortcomings and does not meet the high level of the Powders journal. The following comments should be taken into account.

1. The abstract and conclusions in the presented version do not contain novelty and originality.
2. Lines 65-68 in the Introduction must be supported by references.
3. The authors claim that the samples were synthesized using powder technology, but this is a broad area! It should be written specifically - the samples were synthesized by a mechanochemical method.
4. It is necessary to describe in detail how the microbiological analysis was done. Where did the values in Table 1 come from?
5. In the description of Fig. 1, the authors write that the other 50% of the particles have sizes between 7 and 11 μm (Line 112). Where does this follow from? From Fig. 1 it is clear that there are only 25% of such particles.
6. It is unclear why from Fig. 1 it follows that the particles have sizes from 1 to 20 microns, and from Fig. 2 it is clear that the particle size is about 100 nm?
7. It is completely unclear how Fig. 1 was obtained? Why is the line in Fig. 1 smooth?
8. Figs. 4-6 contain small signatures both along the axes and on the figure itself, nothing is visible. What is this signature on the vertical axis in these figures? Does it mean rel. units? The physical quantity should be written along all axes!!
9. It is enough to imagine Figure 6 and Figure 7. Figures 4, 5 are unnecessary repetitions.
10. There are no errors in Fig. 7.
11. It is completely unclear from the text of the article where the copper is in the samples? Only on the surface of the samples? Or does copper also penetrate the structure of titanium oxide?
12. The authors do not confirm the presence of Cu2+ ions in the samples, so their reasoning in paragraph 4 is not justified. It is necessary to confirm the presence of Cu2+ ions either by XPS or EPR (electron paramagnetic resonance).
13. The authors do not confirm the presence of oxygen radicals and OH radicals in the samples. The authors only refer to literary sources, but the authors must confirm the presence of Cu2+, oxygen radicals and OH radicals in their samples, otherwise all the reasoning and conclusions in paragraph 4 are meaningless.

Comments on the Quality of English Language

The English language should be improved.

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Authors,

I have reviewed your manuscript titled: ”Photosensitization of TiO2 with copper for the photodegradation of organic pollutants in water” and concluded that it is a fascinating study dealing with a topic that is relevant for the readership of the journal Powders. I believe this work is suitable for the Journal of Powders and is of high quality. However, some issues need to be addressed.

 

1. In the Abstract section, add some sentences at the beginning to introduce readers to the topic.
2. In keywords, add TiO2 modifications.
3. In the Introduction section, add details about contaminants present in environmental waters, such as pharmaceuticals, pesticides, and dyes, and cite references https://doi.org/10.1016/j.molstruc.2023.135908 , https://doi.org/10.1021/acs.chemrev.8b00299
4. In 2. Materials and Methods section: Add the place and coordinates where the pond water samples were taken, how they were prepared for degradation, and how they were stored.
5. Could you provide more details about the shape of the particles in the Figure 2 SEM image of TiO2/Cu milled powders?
6. In Figure 4. Absorbance of TiO2 under visible light during 150 min., Figure 5. Absorbance of TiO2/Cu under visible light during 150 min. and Figure 6. Absorbance of TiO2 and TiO2/Cu under visible light during 150 min. The text should be written as Absorbance by…
7. In Figure 8. Images showing color degradation of water exposed to sunlight, and with the addition of 201 TiO2/Cu., the last photograph after 150 min should be of higher quality.