Degradation of Malachite Green Dye by Solar Irradiation Assisted by TiO₂ Biogenic Nanoparticles Using Vaccinium corymbosum Extract

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors describe “Green synthesis of titanium dioxide nanoparticles using Vacciniun corymbosum extract and their applications in sunlight-driven photocatalytic degradation of green malachite dye”. Several major errors still need to be checked before possible publication in the “Sustainability”.

1. The authors need to rewrite the title of the manuscript.
2. Need to provide the numerical results and avoid unnecessary information. Try to highlight the important findings instead of the general information.
3. Reconstruct the keywords.
4. Page 01, line 37, 38: Why did the authors repeat the NPs and TiO₂ NPs abbreviation? Check it carefully.
5. Page 02, line 45: Why again repeat the abbreviation of TiO₂?
6. Authors need to include the role of TiO₂ nanomaterials in photocatalytic process.
7. The most critical concerns are related to the novelty of TiO₂ nanoparticles. Meanwhile, I wonder what is the unique advantage of TiO₂ nanoparticles for photocatalytic dye degradation applications compared with other reports? This should be clarified by the authors.
8. Add the purity of the used chemicals in the text.
9. Suggest to add the schematic representation of the green synthesized TiO₂ nanoparticles protocol.
10. Authors must provide the anatase and rutile phase percentage of the prepared TiO₂ nanoparticles (Figure 1).
11. Should calculate the structural parameters such as lattice parameter, crystallite size, and dislocation density of the prepared samples and explain them in the text.
12. Add the UV-Vis spectra of TiO₂ NPs precursor and also compare with TiO₂ NPs calcinated results (Figure 2).
13. Need to combine the Figures 3 and 4.
14. Add the overall survey spectrum of TiO₂ NPs.
15. Should provide the d-spacing and SAED analyses of the prepared TiO₂ NPs (Figure 6).
16. What is the pHZPC of TiO₂ nanoparticles?
17. Please provide the specific reasons; why the pseudo first order reaction kinetics can be used.
18. Please give the detail reason to support the high reusability of the TiO₂ nanoparticles.
19. Rewrite Figure 8 caption.  
20. Figure 11 is invalid without VB, CB, E_F levels of the prepared TiO₂ NPs.
21. It is recommended that the authors provide their perspective on the future of this research in the conclusion section.
22. Lastly, the text should be reviewed for grammatical, formatting, and punctuation errors.

Author Response

Herein we upload a word document with the answers, and the paper with the corrections highlighted in yellow to the Reviewer 1.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Reviewer #: The manuscript is well-written and the results are presented in a comprehensive manner. Overall the work is good. But further modifications are still needed. Some specific comments are listed below:

1.       Title, the author should change the word “green malachite dye” into “malachite green dye”. Provide uniformly.

2.       Acronyms that first appear should be explained in detail. Such as: XRD, UV-Vis…TEM, etc.

3.       Since the plant extract consists of lot of other components, did authors check the effect of pure extract on the reaction?

4.       - It is not clear if the d values change after the calcined materials.

5.       Clarify the specified nanoparticle (Precursor powders TiO2 or the calcined powders TiO2) used for the XRD, UV-Vis, FTIR, TEM, and Photocatalytic degradation.

6.       Fig. 5, the author should add the survey scan spectra for TiO2 NPs.

7.       It's well known that the adsorption capacity of obtained photocatalyst can greatly affect the removal efficiency of pollutants. I suggest that the authors provide the adsorption behaviors of obtained samples for dye samples before the photocatalytic reaction.

8.       The kinetic studies of photocatalytic performance should be performed.

9.       The quality of some of the figures is low. Please correct.

 

10.   There are some typological and grammatical errors, so authors need to correct them properly.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

There are some typological and grammatical errors, so authors need to correct them properly.

Author Response

Herein we upload a word document with the answers, and the paper with the corrections highlighted in yellow to the Reviewer 2.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In the presented manuscript, the authors provide important results of the green synthesis of the titanium dioxide nanoparticles using Vaccinium corymbosum extract and their applications in sunlight-driven photocatalytic degradation of green malachite dye. The manuscript is well-written, and the research design and utilized methods were clearly stated. The manuscript provides significant results for preparing the nanoparticles using food waste and applying the obtained nanoparticles in the degradation of dyes. However, minor revisions are needed so that the manuscript can be accepted for publication. 1. In the title and line 117 please change Vacciniun to Vaccinium; 2. Discussion of the FTIR Analysis should be revised. There are some quite unproven conclusions, e.g. you mentioned at 1635 cm^-1 (C=O stretching, carbonyl compounds; as ketones, aldehydes, or carboxylic acids). Where is then some additional peak between 1680-1800 cm^-1? You very easily confirmed, according to some peaks that is present in a lot of natural products, presented of polyphenols, polysaccharides etc. Thus, additional spectral (e.g. NMR) or chromatographical (e.g. HPLC) characterization of the extract is needed. Characterization is important for the discussion of the role of the extract in the preparation of the nanoparticles; 3. Please provide a discussion of the role of the extract in the preparation of the TiO₂ NPs.

Author Response

Herein we upload a word document with the answers, and the paper with the corrections highlighted in yellow to the Reviewer 3.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have responded to the reviewer's comments and can be accepted.