Efficacy Studies of Silica Nanoparticles Synthesized Using Agricultural Waste for Mitigating Waterborne Contaminants
Round 1
Reviewer 1 Report
The review summarizes the recent advances in the synthesis of SNPs from barley and rice husk of agricultural waste, as well as their use in the removal of several environmental pollutants from water. In general, it is worth to present such review to demonstrate the novel application of agricultural wastes. The review has been organized well and the language is also well. Anyway, it is better to remediate it and make it more readable and constructive. My comments are as following:
1. The cost of producing silicon dioxide from agricultural wastes by chemical treatment is also high, mainly because the silicon content in plant straws is low and should be less than 10%. And the chemical treatment also needs lots of chemicals and . This manuscript should make a list of silicon content (known) in different plant stalks or other parts of plants, which could provide useful information for researchers in future.
2. In discussing the economic costs of preparing silicon dioxide, it is suggested that the costs of chemical process should also be estimated for comparison. The amount of chemicals used to make SIO2 from plant wastes is also high, which should make the total cost be not low.
3. For a description of the adsorption of SIO2, it would be useful to list the amount, not just the percentage, of adsorption of some silicon dioxide, if available in the literature. The amount of pollutants adsorbed per gram of material is the most important.
4. It is suggested that the simultaneous utilization of carbon and silicon in straw should be considered In the future in the section of “Challenges and future pathways”
.5. There are still some mistakes in the expression or grammar of the article, which need to be revised.
Author Response
Reviewer#1: Comments and Suggestions for Authors
Comments: The review summarizes the recent advances in the synthesis of SNPs from barley and rice husk of agricultural waste, as well as their use in the removal of several environmental pollutants from water. In general, it is worth presenting such a review to demonstrate the novel application of agricultural wastes. The review has been organized well and the language is also well. Anyway, it is better to remediate it and make it more readable and constructive. My comments are as follows:
- The cost of producing silicon dioxide from agricultural wastes by chemical treatment is also high, mainly because the silicon content in plant straws is low and should be less than 10%. And the chemical treatment also needs lots of chemicals and . This manuscript should make a list of silicon content (known) in different plant stalks or other parts of plants, which could provide useful information for researchers in the future.
Response: We thank the reviewer for this excellent suggestion. According to this research, barley, rice and wheat are plant wastes with a very significant amount of silica and their amounts are given in Table 2.
- In discussing the economic costs of preparing silicon dioxide, it is suggested that the costs of the chemical process should also be estimated for comparison. The amount of chemicals used to make SiO2 from plant wastes is also high, which should make the total cost be not low.
Response: We thank the reviewer for this kind suggestion. In this investigation, we have not shown records of cost evaluation for obtaining the waste materials as well as the cost of silica synthesis. It is assumed that waste can be collected, although we know that there is a certain cost involved in transporting it to the processing site. Perhaps, we can use this for a new publication to estimate cost-benefit analysis. Being scientists, we have focussed on the conversion using minimum cost and also taking into consideration green synthesis.
- For a description of the adsorption of SiO2, it would be useful to list the amount, not just the percentage, of the adsorption of some silicon dioxide, if available in the literature. The number of pollutants adsorbed per gram of material is the most important.
Response: We thank the reviewer for this suggestion. In this investigation, we have not shown records of silicon contents in amounts, perhaps this is for the reason that the amount of the contaminants absorbed can be calculated if the percentage and the initial concentration is initially known.
- It is suggested that the simultaneous utilization of carbon and silicon in straw should be considered In the future in the section of “Challenges and future pathways”.
Response: We thank the reviewer for this kind question, in the “Challenges and future pathways” part, we have recommended the conversion of agricultural waste into sophisticated technology for environmental applications.
- There are still some mistakes in the expression or grammar of the article, which need to be revised.
Response: We thank the reviewer for this kind observation. We have reviewed the manuscript once again – both manually and using a software platform for spelling, grammar, and sentence formation, and accordingly, we have made all observable corrections.
PS: Please note that we have made corrections based on your kind input, keeping simultaneously in mind to address comments by other reviewers.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this review, the author presented the different techniques that used in the preparation of silica nanoparticles from agricultural wastes and its applications toward water contamination mitigation. On the whole, the review is of considerable interest and well done. I recommend it to be published after a major revision.
1. The introduction is adequate, however, the properties, microstructure and electron energy level structure for cupper as a catalyst has not been discussed and analyzed in detail, thus, it makes the review article seem shallow.
2. The Authors should also proofread their manuscript (some spelling and grammar errors).
3. - The conclusion is too long and also not targeted to the important aspects described in the manuscript; please rephrase it.
4. If possible, some important and relative reports about Photocatalysis over TiO2 could helped: https://0-doi-org.brum.beds.ac.uk/10.1021/acsomega.1c03693, https://0-doi-org.brum.beds.ac.uk/10.1016/j.jmrt.2022.03.067, https://0-doi-org.brum.beds.ac.uk/10.1016/j.colsurfa.2021.127753.
5. The format of References was unified.
Author Response
Reviewer#2: Comments and Suggestions for Authors
Comments: In this review, the author presented the different techniques that are used in the preparation of silica nanoparticles from agricultural wastes and its applications toward water contamination mitigation. On the whole, the review is of considerable interest and well done. I recommend it to be published after a major revision.
- The introduction is adequate, however, the properties, microstructure and electron energy level structure for cupper as a catalyst has not been discussed and analyzed in detail, thus, it makes the review article seem shallow.
Response: We thank the reviewer for this kind observation. Kindly note that we have focussed on previous methods that have been applied for the synthesis of silica in the introduction, as well as some of the applications. Although, we agree that copper as a catalyst could help, however, we have tried to introduce the method proposed here, in parallel to other methods introduced in literature.
- The Authors should also proofread their manuscript (some spelling and grammar errors).
Response: We thank the reviewer for this observation. We have reviewed the manuscript once again – both manually and using a software platform for spelling, grammar, and sentence formation, and accordingly, we have made all observable corrections.
- The conclusion is too long and also not targeted to the important aspects described in the manuscript; please rephrase it.
Response: We thank the reviewer for this kind observation. We have modified to the extent possible and we hope the reviewer finds it interesting to read.
- If possible, some important and relative reports about Photocatalysis over TiO2 could helped: https://0-doi-org.brum.beds.ac.uk/10.1021/acsomega.1c03693
https://0-doi-org.brum.beds.ac.uk/10.1016/j.jmrt.2022.03.067
https://0-doi-org.brum.beds.ac.uk/10.1016/j.colsurfa.2021.127753
Response: Thanks for the useful references.
- The format of References was unified.
Response: We thank the reviewer for this kind observation. We have worked on the references and made the required corrections. We certainly hope that the reviewer finds it suitable.
PS: Please note that we have made corrections based on your kind input, keeping simultaneously in mind to address comments by other reviewers.
Author Response File: Author Response.pdf
Reviewer 3 Report
This paper describes the environmentally friendly synthesis of silica nanoparticles (SNPs) utilizing a naturally accessible agricultural waste material (barley and rice husk) as green adsorbents for removing petroleum products and also heavy metals (HMs) from contaminated water. The methodological approach seems solid and appropriate. From this work, it is found that silica nanoparticles can be synthesized on a commercial scale using green chemistry principles and are highly efficient materials with promising outcomes for environmental applications.
The paper was well organized and the results are important for environmental preservation and applied science. There is no problem regarding English. Therefore, I feel this paper should be acceptable after minor revisions in view of the following specific comments.
(1) Figure 1: Lack of the indication of (a) and (b) in this figure, although described in Caption.
(2) Figure 3: Lack of the explanation of A, B, C and D in this Caption, although described in this figure.
(3) Figure 4: Lack of the explanation of A, B and C in this Caption, although described in this figure.
(4) Figure 4: Lack of the explanation of A-F in this Caption, although described in this figure.
(5) Table 2: It would be better if significant figure can be united.
Author Response
Reviewer#3: Comments and Suggestions for Authors
Comments: This paper describes the environmentally friendly synthesis of silica nanoparticles (SNPs) utilizing a naturally accessible agricultural waste material (barley and rice husk) as green adsorbents for removing petroleum products and also heavy metals (HMs) from contaminated water. The methodological approach seems solid and appropriate. From this work, it is found that silica nanoparticles can be synthesized on a commercial scale using green chemistry principles and are highly efficient materials with promising outcomes for environmental applications. The paper was well organized and the results are important for environmental preservation and applied science. There is no problem regarding English. Therefore, I feel this paper should be accepted after minor revisions in view of the following specific comments.
- Figure 1: Lack of the indication of (a) and (b) in this figure, although described in Caption.
Response: We thank the reviewer for this kind observation, the correction has been made in the manuscript, according to the reviewer’s suggestion.
- Figure 3: Lack of explanation of A, B, C, and D in this Caption, although described in this figure.
Response: We thank the reviewer for this kind observation. We have included the correction in the manuscript, according to the reviewer’s suggestion.
- Figure 4: Lack of explanation of A, B, and C in this Caption, although described in this figure.
Response: We thank the reviewer for this kind observation. We have included the correction in the manuscript, according to the reviewer’s suggestion.
- Figure 4: Lack of explanation of A-F in this Caption, although described in this figure.
Response: We thank the reviewer for this kind observation. We have included the correction in the manuscript, according to the reviewer’s suggestion.
- Table 2: It would be better if the significant figure can be united.
Response: We thank the reviewer for this mention. All suggested corrections have been made in the manuscript.
PS: Please note that we have made corrections based on your kind input, keeping simultaneously in mind to address comments by other reviewers.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The manuscript is acceptable in the present form since authors have well addressed the questions proposed by referees.
