The Efficient Removal of Methylene Blue Dye Using CuO/PET Nanocomposite in Aqueous Solutions

Round 1

Reviewer 1 Report

In my opinion, this work presents interesting findings on the effect of the applied synthesis route and catalysis. The methodology is reasonable and quite clear. However, some points should be modified in the text. The detailed list is included below:

-English should be corrected throughout all manuscript. Many sentences are incomprehensive.

-The introduction section can be improved and other references can be added

-Quality of the Figures, all figres, should be improved.

-Line 151, pp4, please verify fig 43b.

-Please improve results and dscussion and le kinetic analysis

-Please improve "conclusiosn" section.

Author Response

Response to Reviewer 1 Comments

 

• -English should be corrected throughout all manuscript. Many sentences are incomprehensive.

* The English language has been improved throughout article all, with  all respect

• -The introduction section can be improved, and other references can be added.

* The introduction section has been improved by adding the reviewer's recommended references at lines 43-45 and 64-67.

• -Quality of the Figures, all figures, should be improved.

* All figures (1-8) are original, and the quality of images has been improved as recommended.

• -Line 154, pp4, please verify fig 43b.

* In Line 156, pp5, about the fig 43b, it has been verified and corrected to 3b.

• -Please improve results and discussion and le kinetic analysis.

* The improvement on results and discussion in a kinetic analysis done with all respect.

• -Please improve "conclusion" section.

* The formulation of the "conclusion" section has been improved to suit the paper's content as recommended, as shown on pages 14, lines 377 to 391.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Paper “The Efficient Removal of Methylene Blue Dye Using the Green CuO/PET Fiber Nanocomposite in Aqueous Solutions” by Suhad Abdulrahman Yasin and the colleagues is devoted to their study of synthesis and properties of CuO/PET fiber nanocomposites. Important that waste plastic cups of polyethylene terephthalate are used for the production of nanofibers. Thus, this is green chemical research which could be of interest for Catalysts readership community. I may recommend it for publication after several improvements.

 

1. A more detailed comparison of  NPs, obtained from Sumac (this work) and pomegranate leaves (https://doi.org/10.1007/s00289-019-02919-4, previous work of authors) is recommended. 
2. For the discussion of benefits of Cu particles (lines 61-64) some references may be used, eg https://doi.org/10.1021/acs.chemrev.5b00482, https://doi.org/10.1016/j.jinorgbio.2019.110990, DOI: 10.1021/acs.inorgchem.9b03680, https://doi.org/10.1021/acsaem.0c01014, https://doi.org/10.1021/acsanm.0c00242
3. Improvements of manuscript language is recommended. For example, “green Cu nanoparticles” may be understood either as color or as way of production. Please, specify. Scheme 1 – please, correct “wshed”.
4. Line 163 says that “PET includes 88.4% of carbon and 11.6% of oxygen”. For the initial PET the percentage should be as follows: C: 62.50%; O: 33.30%. Could the authors give a comment on chemical changes, accompanying PET nanofibers production? Is it influence of DCM solution?
5. Line 334 says “1:1 weight of CuO/PET nanocomposite”. What this ratio means?
6. Figure 8. Qe should be deciphered.

Author Response

Second reviewer's comments with authors' answers:

• -A more detailed comparison of NPs, obtained from Sumac (this work) and pomegranate leaves (https://doi.org/10.1007/s00289-019-02919-4, previous work of authors) is recommended. 

 

* More detailed comparison has been added as recommended, as is shown on page 8, lines 213 to 220.

 

• -For the discussion of the benefits of Cu particles (lines 61-64), some references may be used, e.g., https://doi.org/10.1021/acs.chemrev.5b00482, https://doi.org/10.1016/j.jinorgbio.2019.110990, DOI: 10.1021/acs.inorgchem.9b03680, https://doi.org/10.1021/acsaem.0c01014, https://doi.org/10.1021/acsanm.0c00242.

 

* The benefits of recommended references have been added around Cu particles' benefits (pp2, lines 64-68) and the reviewer 1 recommendation. Therefore, we appreciate your interest and all the respect and appreciation of your suggestion.

 

• -Improvements of manuscript language is recommended. For example, “green Cu nanoparticles” may be understood either as color or as way of production. Please, specify. Scheme 1 – please, correct “wshed”.

 

* The manuscript language was improved by removing the word (green) with copper nanoparticles on all pages as recommended. In Scheme 1, the word [washed] was corrected to “wash” as recommended.

 

• -Line 163 says that “PET includes 88.4% of carbon and 11.6% of oxygen”. For the initial PET the percentage should be as follows: C: 62.50%; O: 33.30%. Could the authors give a comment on chemical changes, accompanying PET nanofibers production? Is it influence of DCM solution?

 

*Yes , the influence of solvents used to prepare  PET nanofibers production.

 

• -Line 334 says “1:1 weight of CuO/PET nanocomposite”. What this ratio means?

 

*  This ratio (1:1) has been selected after several ratio optimization tests between CuONPs and PET nanofiber. The ratio (1:1) mean, 0.02 g of CuONPs, was embedded with 0.02 g with PET nanofiber.

 

• -Figure 8. Qe should be deciphered.

 

* in Figure 8. Qe is written in mistakes and has been verified and corrected as recommended. Sorry for that, and many thanks for your notice.

Author Response File: Author Response.pdf

Reviewer 3 Report

Yasin et al. present the synthesis of CuO nps with the natural capped plant extract of Sumac, (Rhuscoriaria L., family Anacardiaceae) residue and production of PET nanofibers through the electrospinning of a waste plastic cups of PET. Subsequently, it was produced a nanocomposite of CuO/PET nanofibers, which was applied for the photodegradation of Methylene Blue. They see a good photocatalytic performance with the CuO/PET fiber nanocomposite under low intensity UV illumination. Nevertheless, there are a few more major, as well as some minor issues which need to be addressed, as follows:

1) I suggest the addition of CuO and PET to the keywords list since they are the focus of this work.

2) In general, the figures have very poor quality. Moreover, it is impossible to read the scales in Figure 2.

3) In line 155, the sentence does not end.

4) Figure 6 appears separate. Besides that, the plots should have the same formatting.

5) Depending on the conditions/setup of the photocatalysis study, the degradation of methylene blue in aqueous solution differs, which can mask the photocatalytic performance of a certain material. Thus, the authors should provide the photocatalytic degradation of the MB solution under the same conditions, to serve as control.

6) Did the authors study the photocatalytic performance of the CuO nanoparticles? I also would like to see this comparison.

7) In section “2.6. The Kinetics of MB degradation by CuO/ PET Nanocomposite” and specifically in Figure 7, the authors present the kinetics of MB degradation with the nanocomposite fabricated. However, the k values are not presented, just the fitting curves. These values should be presented and compared with the literature.

8) How was performed the study presented in section “2.7. Influence of pH and MB Dye Concentration on Photodegradation”? This section is not very clear.

9) In sub-section “3.4 Preparation of CuO/PET Nanocomposite” the authors present the mass, I suppose, as gm, but this is not how the mass units should be presented.

10) The information about the absorbance data measurements should be added to the “Materials and Methods” section.

Author Response

Third reviewer's comments:

• - I suggest the addition of CuO and PET to the keywords list since they are the focus of this work.

* CuO and PET have been added to the keywords as recommended.

• -In general, the figures have very poor quality. Moreover, it is impossible to read the scales in Figure 2.

* The figures have been changed and the quality has improved.

• -In line 155, the sentence does not end.

* after revision of the mentioned line is done.

• -Figure 6 appears separate. Besides that, the plots should have the same formatting.

* it has been corrected as suggested.

• -Depending on the conditions/setup of the photocatalysis study, the degradation of methylene blue in aqueous solution differs, which can mask the photocatalytic performance of a certain material. Thus, the authors should provide the photocatalytic degradation of the MB solution under the same conditions to serve as the control.

* According to many research published, there is a minor effect of light irradiation on the MB dye without the catalyst. Therefore the authors decided to be neglected. https://doi.org/10.1016/j.btre.2020.e00518

• - Did the authors study the photocatalytic performance of the CuO nanoparticles? I also would like to see this comparison.

* Sure, the photocatalytic performance of the CuONPs has been tested before preparing of CuO/PET composite.  Therefore, it has been chosen for this study. However, the work was focused on the CuO/PET composite performance, and no further optimization tests have been done for CuONPs.

 

• - In section "2.6. The Kinetics of MB degradation by CuO/ PET Nanocomposite" and specifically in Figure 7, the authors present the kinetics of MB degradation with the nanocomposite fabricated. However, the k values are not presented, just the fitting curves. These values should be presented and compared with the literature.

* the value of k has been added in the mentioned section

• -How was performed the study presented in section "2.7. Influence of pH and MB Dye Concentration on Photodegradation"? This section is not very clear.

* Regarding the influence of pH, several vials prepared contain CuO/PET and 5 ml of 10 ppm MB dye. The pH has adjusted for each vial using HCl and NaOH solution. Finally, the better pH for the degradation process was chosen.

Regarding the effect of the initial concentration of MB dye, Unfortunately, it was missed, and A new paragraph has been added to this section.

• - In sub-section "3.4 Preparation of CuO/PET Nanocomposite" the authors present the mass, I suppose, as gm, but this is not how the mass units should be presented.

* it is corrected with all respect

• - The information about the absorbance data measurements should be added to the "Materials and Methods" section.

* The images of the spectral absorption analysis, along with its explanation, have been placed in this particular site to match the other information linked to it to make it easier for readers to connect the desired information. Besides, most of the published articles work in this format.  As well as in line with the instructions of the current journal. with the utmost respect and appreciation for your suggestion

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

This revised article can be published. 

Author Response

Thank you very much with all respect

Reviewer 2 Report

Authors presented an improved version of their manuscript. This one is fine with me. I could recommend several slightest changes, in accord with my previous remarks.

 

1. More details comparison has been added as recommended, as is shown on page 8, lines 213 to 220.

This is good. Please, check the meaning of the new sentence “Unlike the path prepared separately”.

 

2. The benefits of recommended references have been added around Cu particles' benefits (pp2, lines 64-68) and the reviewer 1 recommendation. Therefore, we appreciate your interest and all the respect and appreciation of your suggestion.

At the moment, only one more reference (# 13) is added. The rest of previously recommended articles also could be useful for the final version

 

3. The manuscript language was improved by removing the word (green) with copper nanoparticles in all pages as recommended. In Scheme 1, the word [washed] was corrected to “wash” as recommended.

This is ok, thank you

 

4. Yes ,the influence of solvents used to prepare PET nanofibers production

Now it is clear, thank you. An additional sentence regarding this point may be added to the text (to avoid the similar question from future readers)

 

5. This ratio (1:1) has been selected after several ratio optimization tests between CuONPs and PET nanofiber. The ratio (1:1) mean, 0.02 g of CuONPs, was embedded with 0.02 g with PET nanofiber

Thank you. A comment on optimization stage could be added to the text as well

 

6. in Figure 8. Qe is written in mistakes and has been verified and corrected as recommended. Sorry for that, and many thanks for your notice

Ok, thank you. More detailed legenda for axis may be recommended (current “Removal %” is not very informative)

Author Response

reviewer comments…. * authors' answers)

• This is good. Please, check the meaning of the new sentence "Unlike the path prepared separately.-"The sentence on page 8, line 222-223, is corrected..all respects.

 

• The sentence on page 8, line 222-223, is corrected..all respects.
• -All recommended references have been added, as shown in lines 68-71.

 

• At the moment, only one more reference (# 13) is added. The rest of previously recommended articles also could be useful for the final version
• All recommended references have been added, as shown in lines 68-71.

 

• Now it is clear, thank you. An additional sentence regarding this point may be added to the text (to avoid the similar question from future readers) 
• The sentence regarding this point on page 6, line 175-176, has been added. All respects.

4- Thank you. A comment on optimization stage could be added to the text as well.

• It has been improved as recommended at line 361-362—with all respect to your suggestion.

5- Ok, thank you. More detailed legenda for axis may be recommended (current "Removal %" is not very informative).

• In Fig 8, the word "Removal" has been changed to "Degradation" to be more informative as recommended. All respect.

Author Response File: Author Response.pdf

Reviewer 3 Report

In my opinion the revised manuscript can be published in the present form. 

Author Response

Thank you very much with all respect