Purification of Pesticide-Contaminated Water Using Activated Carbon from Prickly Pear Seeds for Environmentally Friendly Reuse in a Circular Economy

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors The manuscript describes the use of activated carbon from pear seeds for pesticide removal and investigates physicochemical aspects of the adsorption process. The text is mostly clear and concise and may be of interest to the audience reached by the journal. Hence, I recommend its acceptance after some revisions, as stated below.   - It is not clear if the pesticide Deltamethrin is soluble in water. Hence, it should be clarified in which media the adsorption experiments were performed. - Regarding the acidic groups found on the surface of activated carbon, is there any publication on similar systems that corroborate these results using spectroscopic techniques, like XPS? - Pore size distribution seems to lay around 4 nm (Figure 3), although authors state that it is between 2 and 50 nm. - Authors are invited to provide more SEM images of the materials. The only one presented in the manuscript has a low resolution and might not be representative for the whole material. - What are the lines that adjust the experimental points displayed in Figure 7? - In Table 6, why were the thermodynamic parameters calculated for one single temperature?   - English editing is recommended in the whole manuscript. Comments on the Quality of English Language

- English editing is recommended in the whole manuscript.

Author Response

Dear Reviewer,

Thank you for taking the time to review our paper and for your valuable comments and suggestions. They were very insightful, and we appreciate the positive feedback. We hope that this revised version is satisfactory for publication in the 'Sustainability' journal.

We are now submitting our edited revised manuscript, considering all the necessary corrections. We believe that the quality of our paper has been improved, and we hope that it now meets the required publication standards in 'Sustainability.'

Thank you in advance, and we look forward to hearing from you.

Best regards,

Prof. Hatem DHAOUADI

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript reports the detoxification of water contaminated with pesticides using activated carbon from prickly pear seeds. The topic is interesting. However, major revisions are required. Suggestions and questions are given below.

1.     The abstract is suggested to be revised. It is not necessary to state “For a better orientation of its uses, its characterization has proven to be essential”. More results are suggested to be added.

2.     Various adsorbents have been developed for waste water treatment. More recently published literature are suggested to be cited to enrich the content, such as Journal of Colloid and Interface Science 2022, 608, 2860-2869; Langmuir 2022, 38 (50), 15729-15739; Colloids and Surfaces A: Physicochemical and Engineering Aspects 2021, 612, 126038.

3.     Please go through the whole manuscript to remove typos. For example, “(Sufeitila” in line 136 and “(AC)” in line 157 should be revised.

4.     A space is required to be added between the number and unit. The units should be written in the same style.

5.     The English language needs to be further polished. For example, “a solution of H3PO4 3M” in line 140 should be revised.

6.     Why does the concentration H3PO4 fixed at 3M, and activation temperature fixed at 800 oC? How about the influence of different concentration and activation temperature?

7.     The nitrogen adsorption-desorption isotherm is suggested to be added in Figure 3.

8.     The scale bar should be added in the SEM image in Figure 4. High resolution images with larger magnification are necessary if available.

9.     Error bar should be added in Figures, such as Figure 5, Figure 6 and Figure 7.

Comments on the Quality of English Language

 Moderate editing of English language is required。

Author Response

Dear Reviewer,

Thank you for taking the time to review our paper and for your valuable comments and suggestions. They were very insightful, and we appreciate the positive feedback. We hope that this revised version is satisfactory for publication in the 'Sustainability' journal.

We are now submitting our edited revised manuscript, considering all the necessary corrections. We believe that the quality of our paper has been improved, and we hope that it now meets the required publication standards in 'Sustainability.'

Thank you in advance, and we look forward to hearing from you.

Best regards,

Prof. Hatem DHAOUADI

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Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

In this manuscript, the authors studied the detoxification of pesticides-contaminated water with activated carbon. While I would recommend acceptance for publication, I do think the authors need to carefully revise the manuscript.

1. There are lots of typos in the manuscript. For example, "aplication" in the title. In table 2, "acidity fonctions". In line 57, "light.Theyare" missed space. In line 136, bracket was missing for "Sufeitila". There are too many similar typos to point out, so please go through the whole manuscript to correct them. 

2. In the manuscript, the authors always put full name and abbreviations together. For example, "activated carbon (AC)". You only need to pick one from the two after the first appearance in the manuscript. Don't have both everywhere. Also, if you want to go with abbreviations, you do not need brackets. 

3. The SEM image in figure 4 should have a scale bar. Please use a clean SEM image without the boxes where you collected EDX data.

4. With Figure 6, could the authors explain why the removal rate are similar for different concentrations of delamethrin? Shouldn't the lower concentration have higher removal rate?

5. Format should be consistent. ppm and mg/L were both used; for figures, the axis titles position should be consistent. 

6. Figure 7, the y axis should be q instead of qe, since qe is the value after reaching equilibrium. Also, please explain which order model was used in these plots. 

7. Please make sure the figure title and caption are consistent.

8. In table 7 and 8, the comma in numbers should be decimal.

Comments on the Quality of English Language

The overall English language is readable but could be improved.

Author Response

Dear Reviewer,

Thank you for taking the time to review our paper and for your valuable comments and suggestions. They were very insightful, and we appreciate the positive feedback. We hope that this revised version is satisfactory for publication in the 'Sustainability' journal.

We are now submitting our edited revised manuscript, considering all the necessary corrections. We believe that the quality of our paper has been improved, and we hope that it now meets the required publication standards in 'Sustainability.'

Thank you in advance, and we look forward to hearing from you.

Best regards,

Prof. Hatem DHAOUADI

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Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

Unintelligible title, edit.

The introduction is long, shorten it and be more specific and concise in the introduction itself.

Why did you use Prickly Pear Seeds, post a picture? Why aren't you some other precursor? And then compared.

In the experimental part, line 139...you said that it was crushed and sieved, what is the granulation? And what weight was taken?

Line 140...what amount of H3PO4? And why exactly, another acid, base or some salt could have been used for chemical activation.

Line 145...carbonization and pyrolysis are not the same...they are similar.

What amount of N2 flow?

Why didn't you try another temperature, lower or higher than 800C and another retention time and then compare the obtained active carbon materials and their properties as well as their application.

In table 1. Why didn't you mention Temkin's model?

Paragraph 3.1.4 where is your adsorption and desorption isotherm, curve type? alpha with ? as well as the pore volume?

Table.3. why is there so much P?

In addition to Boehm titration, why didn't you do, for example, FTIR and elemental analysis of the obtained final product?

Why haven't you tried the sorption of methyl orange or some other organic compounds, heavy metals.

Author Response

Dear Reviewer,

Thank you for taking the time to review our paper and for your valuable comments and suggestions. They were very insightful, and we appreciate the positive feedback. We hope that this revised version is satisfactory for publication in the 'Sustainability' journal.

We are now submitting our edited revised manuscript, considering all the necessary corrections. We believe that the quality of our paper has been improved, and we hope that it now meets the required publication standards in 'Sustainability.'

Thank you in advance, and we look forward to hearing from you.

Best regards,

Prof. Hatem DHAOUADI

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Authors provided all requested information. The manuscript is suitable for publication now.

Author Response

Dear Reviewer,

We deeply appreciate your positive feedback.

Thank you for taking the time to review our paper and for your valuable comments and compliments.

Best regards

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript has been revised according to the comments. However, major revisions are required since some issues still unsolved. Suggestions and questions are given below.

1.     The data of adsorption capacity is suggested to be highlighted in the abstract.

2.     “purification of contaminated water” could be added as a keyword.

3.     Various nanomaterials have been developed for the purification of contaminated water. More recently published references are suggested to be cited in the introduction section to keep update, e.g. Coordination Chemistry Reviews 2024, 502, 215612.

4.     The carbonization process took place in a preheated oven for 40 minutes at a temperature of 800°C. Is that true? The temperature of carbonization process is always raised from room temperature to the aimed temperature at a constant rate. Please refer and cite Rare Metals 2022, 41 (10), 3432-3445; Journal of Energy Storage 2024, 77, 109859

5.     “Zero charge value” in line 331 is suggested to be revised as “zero charge value”.

6.     Please double check the whole manuscript to remove typos. For example, “meq g-1” in line 307 should be revised. “mg/L” in the Figure 7 and 9 should be revised as “mg L-1”. “mg/g” in the Figure 8 should be revised as “mg g-1”.

Comments on the Quality of English Language

Minor editing of English language is required.

Author Response

Dear Reviewer,

Thank you for taking the time to review our paper and for the constructive comments and suggestions.

Please find below our point-by-point responses. We have incorporated all comments and recommendations into the newly submitted version. Changes to the manuscript text are highlighted with green font. We hope that our revised paper now meets the required standard for publication. Thank you in advance, and we look forward to hearing from you.

Thank you again for your cooperation.

Best regards,

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

Dear authors,

you have adequately responded to my remarks and suggestions, with that I give you a positive opinion for accepting the work in the journal.

Author Response

Dear Reviewer,

We deeply appreciate your positive feedback.

Thank you for taking the time to review our paper and for your valuable comments.

Best regards

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript has been well revised according to the comments and could be accepted now.