Extraction and Characterization of Biogenic Silica Obtained from Selected Agro-Waste in Africa

Round 1

Reviewer 1 Report

Dear editor,

I have revised the manuscript entitled "Extraction and characterization of biogenic silica obtained from 2 selected agro-waste in Africa", where the authors evaluate the production of biogenic silica from african biomass waste. The authors describe the obtained products in a thorough way by using many analytical techniques. Overall, the manuscript is well-written and interesting for the scientific community. However, there are some minor issues that should be improved/corrected before acceptance.

1-More quantitative results can be included in the abstract.

2-The novelty of the work must be stated and highlighted in the text.

3-I suggest to summarize the results a little bit therefore the lenght of the manuscript can be reduced. Now it is too long.

4-There are many typos, missing commas and slightly incomplete sentences all along the manuscript. Please, proofread the text carefully. Some examples can be found in lines 163, 185 or 214.

5-In line 163 the coconut husks abreviation is missing. Please, include it here.

6-All the units should be written in the same style. Please, select an apporpiate style and modify them accordingly.

7-Please, include more quantitative results also in the conclusion section.

Author Response

Dear reviewer,

 

thank you very much for your very helpful hints and suggestions.

Please find all made adaptations in the document attached.

 

With kind regard on behalf of the authors,

Steffi Formann.

Author Response File: Author Response.docx

Reviewer 2 Report

The article entitled, “Extraction and characterization of biogenic silica obtained from selected agro-waste in Africa” provides a viable solution to the waste biomaterials.

The biological systems are notably efficient in accumulating the inorganic inclusions with high purity. It is interesting to collect high purity silica from the biological systems.

However, the following suggestions/ revisions are being proposes so the  authors could consider for better presentation of their work:

1) Since the work deals with annealing of biomaterials in air for producing the SiO₂, and also presented in the Table 2, the carbon content in the system is huge (̴ 46-50 % wt db). Considering global warming is such an important issue these days, it would be suggested that if authors can enlighten the importance in their introduction for the generation of SiO₂ in trade of CO₂/CO.

2) Authors have explained the thermal degradation of the biomaterials and explained using material characterization techniques. Figure 5 shows the visual appearance of the SiO₂ samples.

However, if authors can include few FE-SEM images of the samples to reveal the micro structures of the particulates, that'd value add to their report. Even optical images with 100X magnification and high resolution could be very helpful to understand the particle size of silica they bio-synthesize.

3) In figure 4, the legend is labelled as ‘Si₂O’ which may be corrected to ‘SiO₂’.

Author Response

Dear reviewer,

 

thank you very much for your helpful support, hints and suggestions. All adaptations made are described in the document attached.

With kind regards on behalf of the authors,

Steffi Formann.

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript “Extraction and characterization of biogenic silica obtained from selected agro-waste in Africa” is interesting and within the scope of the journal but some minor changes should be addressed:

1. At line 56, please use [16-18] instead of [16]-[18].
2. The fly ash represents an important source of silica. It will be interesting to discuss briefly about it (please see https://doi.org/10.3390/nano10030474 ). Also, it will be interesting to mention some applications of synthesised silica (please see https://doi.org/10.37358/RC.19.5.7161).
3. At line 213, please use mL/min instead of ml/min.
4. Please check and rewrite the references according to journal instructions.
5. Try to remove the gridlines from figure 8.

Author Response

Dear reviewer,

 

thank you very much for your helpful and precious support, hints and suggestions. All adaptations made are described in the document attached.

With kind regards on behalf of the authors,

Steffi Formann.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Upon review, the manuscript can be accepted for publication.