Potential of Biosynthesized Silver and Zinc Oxide Nanoparticles from Carissa opaca Extracts for Antimicrobial Activity and Wastewater Treatment

Round 1

Reviewer 1 Report

 

Manuscript ID             Sustainability-2379226

 

I have read the manuscript (Brief report) entitled “Potential of Biosynthesized Silver and Zinc oxide Nanoparticles from Carissa opaca Extracts for antimicrobial activity and wastewater treatment”. The authors have detailed the biosynthesis of silver nanoparticles (AgNPs) and zinc oxide nanoparticles (ZnO NPs) using the leaf and stem extract of a therapeutic plant Carissa opaca. The NPs were found good in their antibacterial and catalytic properties. This work is worthwhile to be publish in this journal after minor revisions. The following issues should be addressed:

1.      Rewrite the abstract with including the statement of problem.

2.      Explain the novelty of the work.

3.      Revise and simplify the last paragraph of the introduction, avoid the use of complicated sentences.

4.      How the leaves and stem of Carissa opaca were identified?

5.      Indicate the purity of the chemicals used.

6.      In Graph 1 figures are not properly adjusted. Revise and improve resolution. Indicate the bandgap value.

7.      Why the concentration of Ag and ZnO NPs is different from leaf extract and stem extract as detected by ICP-OES.

8.      Resolution of all figures is low, must revise.

9.      Check the XRD patterns and make corrections.

10.  Figure 7&8 and graph 7&8 are disturbed, readjust them.

11.  Antibacterial and dye degradation mechanism can be strengthened using recent work (https://doi.org/10.1016/j.jece.2021.105534,https://doi.org/10.1016/j.colsurfa.2021.126176)  

12.  Scavenging test should be used to confirm the active species.

13.  Provide complete conditions used in the dye degradation test.

14.  The language should be improved and writing style must be consistent.

 

Should be checked carefully

Author Response

All the graphs are redrawn using origin software and reanalyzed.

Author Response File: Author Response.pdf

Reviewer 2 Report

Upon reviewing your manuscript intitled: Potential of Biosynthesized Silver and Zinc oxide Nanoparticles from Carissa opaca Extracts for antimicrobial activity and wastewater treatment. I find your work interesting, but I do not believe it can be published in its current form. Therefore, some revisions must be done so that it may be published in this journal. I have the following comments and recommendations.

- The summary is qualitative and does not present the main results. The characterization techniques do not need to be mentioned in the abstract, but the main results obtained from it.

-The introduction of relevant background and research progress was not comprehensive enough. Some sentences need to be referenced.

- Include the purity of the raw materials used.

- Why the authors selected Methylene Blue (MB) for the degradation study? When there are lot of reports are available in the literature.

- The quality of Figure 1 is poor and should be improved. In addition, more details on how the gap was calculated should be provided. As well as a deeper discussion of the observed changes

- The quality of figure 2 and 3 is poor. must be improved.

- The quality of figure 2, 3, 3 and 4 is poor. It must be improved. I suggest that the authors make a single figure with all the curves, this way it will be easier to discuss and visualize the changes.

- In the morphological analysis, I suggest that the authors make a figure with all the images.

- X-ray diffraction analysis is about. This must be improved since the inclusion of dopants strongly affects the structure of ZnO. Miller indices, crystallographic chart, 2theta in (degrees). These are details that should be included and discussed in the text.

- The crystallite sizes for the various samples were calculated by the Scherrer equation. However, it is well known that the peak broadening is impacted by other factors such as instrument-related broadening, residual stresses in crystals, etc. How did the authors determine or subtract these well-known parameters?

- The XRD pattern must be presented in a single Figure. Changes in peaks, crystallite sizes, lattice parameters and lattice strain will be shown and discussed.

- There is no experimental data on chemical stability of synthesized materials

 

- As an environmental restoration material, recycling must be considered, and some tests and analysis should be supplemented.

Author Response

All the Graphs are redrawn using origin software and reanalyzed to calculate various parameters of nanoparticles.

Author Response File: Author Response.pdf

Reviewer 3 Report

Manuscript Number: sustainability-2379226-peer-review-v1

Manuscript Title: Potential of Biosynthesized Silver and Zinc oxide Nanoparticles from Carissa opaca Extracts for antimicrobial activity and wastewater treatment

The current study focusses on biosynthesis of stable silver nanoparticles (AgNPs) and zinc oxide nanoparticles (ZnO NPs) from the leaf and stem extract of a therapeutic plant followed by their characterization studies. The manuscript needs some major corrections before getting accepted for publication. The comments are listed below,

1.      In the current study, rather than eco-friendly biosynthesis of tiny and stable nanoparticles, what is the major novelty of the work in comparison with the current trend?

2.      What is the innovative work carried out in the synthesis of nanoparticles? Compare the same with the numerous reported works.

3.      The novelty of the work must be explained in detail in the introduction which is found to be missing.

4.      All the graphs must be modified like one for AgNPs and other for ZnONPs irrespective from where they are extracted.

5.      The quality of the graphs must be improved. It is seen that all the graphs are directly got from the characterization studied which cannot be used for a journal. It is advised to use a proper graph plotting software to redraw the graphs.

6.      What is the inference of the FTIR reported in the work. It is seen only the explanation of the graphs and the inference of the same needs to be included. Justify the same.

7.      The scale of the HRTEM images seems to be very dim. Modify the quality of the HRTEM images.

8.      Graph 7 & 8 seems to be drawn in MS-Excel. Change it to suit with the journal standards.

9.      Conclusions seems to be very vague. Add the important findings of the work in the conclusion part of the manuscript.

English language can be improved.

Author Response

All the Graphs are redrawn using origin software and reanalyzed to study various parameters of nanoparticles.

Author Response File: Author Response.pdf

Reviewer 4 Report

 

Manuscript-ID: sustainability-2379226

 

The authors reported the synthesis of AgNP and ZnONP in a biological way. The synthesized nanoparticles are characterized by different techniques, and those particles are applied for antibacterial activity and wastewater treatment. The manuscript is written well, but lacks information on various fronts. I suggest authors kindly consider the following comments/questions constructively to improve the manuscript's quality.

 

1. The authors do not assess their findings against past studies. The correlation between their study and other relevant works appears to be missing.

2. Equations were not shown properly in the manuscript. Authors are requested to look the matter seriously.

 

3. The quality of the figures and related captions must be improved. 

 

Author Response

All the Graphs are redrawn using origin software and reanalyzed to calculate various parameters of nanoparticles.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

This version may be considered for publication.

Author Response

Rectified as per kind suggestions

Reviewer 3 Report

The manuscript in the current form can be accepted for publication.

Author Response

Rectified as per kind suggestions