Solar-Light-Driven Ag₉(SiO₄)₂NO₃ for Efficient Photocatalytic Bactericidal Performance

Round 1

Reviewer 1 Report

Authors can consider below comments to improve the manuscript quality.

Abstract:

In abstract authors wrote that two types of bacteria were employed for bactericidal purposes: gram-negative (E. coli) and gram-positive (Streptococcus pneumoniae) (S.aureus). There is no information about Streptococcus pneumoniae in the text. What happened to Streptococcus pneumoniae? Bacteria should also be in italic. 

Ag9(SiO₄)₂NO₃ should be be: Ag₉(SiO₄)₂NO₃

Introduction:

ROS[18-20] - no spaces between ROS and number

Ag₉ (SiO₄)₂NO3, Ag₉(SiO₄)2NO₃ – should be Ag₉(SiO₄)₂NO₃

Experimental

2.1. Synthesis

In experimental methods some information is missing. Please provide information about the source of reagents: AgNO₃, Na₂SiO₃

2.2 Characterization

Please provide information about equipment manufacturers.

2.3. Photocatalytic inactivation performance

This part should be described in more detail.

E. coli and S. aureus - bacteria in all manuscript should be write in italic. Please specify strain and supplier of bacteria

What is bacteria concentration? 105 cfu/ml or 10⁵ cfu/ml

What kind of agars were used? There are no information about type and name of agars and supplier.

As a light source, a 300-watt lamp was used. – please provide name of lamp, manufacturer or supplier.

What were the intensity of the radiation (lamp and natural sunligh)?

2.4. Photocatalyst mechanism

This part also should be described in more detail. Please provide information about the source of reagents.

3. Results and Discussion

Ag9 (SiO4)2NO3 - please write the correct name of the compound - it's about the indexes

Gram-positive and Negative Bacteria – (please standardize naming, once with hyphen and once without). E.coli and S.aureus should be in italic.

There is no reference to figure 4 in the text.

Please describe your results in more detail. „In comparison with previous work, as indicated in Table (1), this work exhibits excellent performance”. Describe the comparison in a few sentences.

Author Response

Dear reviewer 1, 

Thank you for your feedback and valuable comments. We replied to comments point by point.

Best Regards

Author Response File: Author Response.docx

Reviewer 2 Report

The article must be reviewed and the requested aspects improved.

 

1. Review throughout the document the bacterial efficiency of E.coli and S.aureus:

I understand that 1% of the catalyst is used with an initial concentration of 2mg/mL, so the final concentration (in the agar) is 0.002mg/mL. If this last concentration is expressed in ug/mL it would be 2 ug/mL....but it would be convenient to express it in a way that is adequate for the reader's understanding and throughout the text.

For example, Table 1 shows the concentration with which they have worked (0.002 mg/mL = 2 ug/ml), which has been the one with which they have achieved the inhibition of bacteria, but it seems that the authors do not distinguish between the initial concentration and that of inhibition of bacteria, since it does not appear correctly in the headings of Table 2.

In abstracts it is said: “bactericidal activity in ultra-low concentrations (0.0002 ? mg/ml) (of photocatalyst by solar and simulated light, respectively, after 10 minutes”, but it does not differ if it is the same for E.coli and for S .aureus.

It is understood that 2 ug/mL has inhibited both bacteria, but it is not clear. It is necessary that they clarify it somewhere and explain correctly the way of operating in material and methods. In addition, in table 1 they do not say which microorganisms have been studied in the other incorporated catalysts.

 In the abstracts they comment: “The survival rate vs. time was also investigated, and 0.2 percent of the survival cells were reported within 6 minutes at a photocatalyst dose of 0.002 mg/ml.” It seems to me that this form of expression is messy and perhaps they could say that the survival rate was studied for XX time, resulting in 99.8% inhibition (instead of saying that only 0.2% of cells remain) for the highest concentration studied.

 

2. In section 2.3 it says: “A w % of Ag9(SiO4)2NO3 concentration

of 2 mg/ml was employed, with a final concentration of 0.0002 mg/ml, and a bacterial

concentration of 105 cfu/ml”. And it should say 2 ug/ml or better 0.002 mg/ml. It is seen that they have placed one more zero by mistake.

And the bacterial concentration should be potential 10 5 CFU/mL (with superscript number 5)

 

3. Typographical errors such as: subscripts in formulas
Abstracts: Ag9(SiO4)2NO3

Introduction and 2.1 Synthesis: Ag9(SiO4)2NO3

and the italics of bacteria....on all sides!

On the other hand, it is necessary that they explain in an explicit way how they carry out the seeding in sunlight or the lamp (focal distance) or how they incubate the samples, and the addition of the catalysts and the control, etc…

4. 2.2 Characterization

An FTIR-ATR spectrum and thermal analysis of TG/DTA or DSC of the new compound synthesized by a green method must be characterized and provided.

5. 2.4 Photocatalyst mechanism

It says 1Mm and it should say 1mM

6. Figure 5 does not provide statistical data on the number of samples performed and the standard deviations. In figure 2 they put the 3 attempts they have made, but we do not see repetitions and deviations and the statistics. 

Author Response

Dear Reviewer 2,

Thank you for your feedback and valuable comments. We replied to comments point by point.

Best Regards 

Authors

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

In my opinion, the manuscript has been sufficiently improved and can now be published in its current form. 

Reviewer 2 Report

Accept in present form

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.