Porous Biochar Materials for Sustainable Water Treatment: Synthesis, Modification, and Application

Round 1

Reviewer 1 Report

The submitted manuscript is a review paper concerning development of biochar sorbents derived from biomass, its applications and functionalization procedures to handle various contaminants to be removed from the wastewater.

I am convinced that combining of bio-based sorbents into an integrated processes is one of the key technologies in the nearest future. The material meets sustainability criteria in terms of net carbon emission (zero or negative) and it’s relatively cheap. However, reasonable postproduction modification is required to obtain a satisfactory performance to be competitive when comparing to alternative techniques.

The overall quality of the manuscript is fair. The review comprises more than 100 references, which are relevant and up to date. In multiple places Authors repeat the same or similar information, summarized by a conclusion that material is cheap, efficient and sustainable. A very little information is about properties of material and the process parameters (i.e. the specific surface area of the sorbent is mentioned once, but there is no information about the process realization – if it is applied in fixed packed beds or fluidized, what are sizing parameters in terms of process kinetics, e.g. residence time, superficial velocities through a porous bed, if it can be regenerated and reused or it’s a disposable material etc.).

The English is not bad, however in some places the paper requires significant improvements – a careful revision, preferably by a native English speaker, is strongly recommended.

Please find below list of remarks addressed to a specific fragments in the manuscript:

• Line 20: “In order to being sustainable development,…” (English)
• Line 23: “… by the reaction of biomass.” (English: maybe “…as a result of biomass decomposition”?)
• Line 24: “…many uses…” (maybe many applications?)
• Line 39: a double space before “ has been”
• Line 48: “.” is missing after [2]
• Line 48: “Due to…” (instead of “Because of…” – because is repeated)
• Line 48: “… is becoming…” – I would suggest using present perfect continuous (not present continuous)
• Line 57: “…enhance soil health.” (Maybe: “… improve soil quality”?)
• Line 70: a word “amendment” is not correctly used in this context
• Line 73: “large specific surface area…” – repeated (and no range of value provided)
• Line 83: “.” Dot missing at the end of sentence
• Line 139: “weave features” - ??? (English)
• Line 154: “low porosity” – please provide figures for low and high values (which are satisfactory and expected for sorbents)
• Lines 164-165: wors “modification” used 3 times, “efficiency” 2 times in a single sentence
• Line 205: “we discover” (impersonal, and past tense)
• Line207: a word “qualities” is not correctly used in this context
• Line 245: a space is missing before “Richardson’s…”
• Line 273: “…and freeze-thaw cycles procession” (English – maybe “f-t processing cycles”?)
• Line 278: “It was found…” (was missing)
• Line 279: :The BET of processed biochar…” – The BET area (or BET spec. surface area)
• Line 280: “…more than before” (English + not clear before what?)
• Line 280: the capacity is a parameter – it can increase (the process can be intensified or enhanced)
• Line 286: what are “difficult organic substances”?? (English)
• Line 292: Printing (lower case “p” in the sentence)
• Line 293: not clear “biochar materials are always used in parallel with adsorption, catalytic, and degradation” (English – I guess maybe the Authors meant “…biochar mat. are usually used in and integrated process including (or combining) ad, cat, deg”)
• Line 296: Biochar (lower case “b” here)
• Line 297: “…treatment d.” (an editing mistake)
• Line 298: water or wastewater?
• Line 306-307: English
• Line 309: “…a greater production cost advantage…” ?? (not clear)
• Line 314: “…increase the settling.” (English)
• Line 314-315: repeated the same information as in Lines 313-314
• Line 314: “.” (Dot missing after “settling”)
• Line 320: “…good for increasing soil fertility after wastewater treatment” ??? (maybe you should add “…when dewatered digested sludge containing biochar is discharged into environment”?)
• Line 340: This sentence is more relevant to chapter 4.3
• Line 356: please revise this “FeSO4-7H2O at pH 5.0. of FeSO4-7H2O”
• Line 365: Shengquan (upper case letter)
• Line 368: lakshmi’s team… (upper case letter) – and I have not found this name in the References ([98] is Lingamdinne et al.)
• Line 382: “… oil development” ?? (English)
• Line 391: “limelight” ?? (En)
• In chapter 4.4: Rhodamine B is upper case in lines 398 and 400, and lower case in 403
• Line 432: “… can be tried” (En)
• Conclusions: Please indicate clearly what has already been achieved and published, and what technologies are at the development stage (please try to be more specific – when not achieved, please rate the developments level and achieved results if they are near or still far from expected/satisfactory results or if there are prerequisites/premises for achieving them)

Author Response

COMMENTS FROM THE EDITOR AND/OR REVIEWERS

Reviewer #1: The overall quality of the manuscript is fair. The review comprises more than 100 references, which are relevant and up to date. In multiple places Authors repeat the same or similar information, summarized by a conclusion that material is cheap, efficient, and sustainable. A very little information is about properties of material and the process parameters (i.e. the specific surface area of the sorbent is mentioned once, but there is no information about the process realization – if it is applied in fixed packed beds or fluidized, what are sizing parameters in terms of process kinetics, e.g. residence time, superficial velocities through a porous bed, if it can be regenerated and reused or it’s a disposable material etc.).

Response: Thank you for your comments. The repeated information of references has been removed, and new references have been added in the revised manuscript.

The English is not bad, however in some places the paper requires significant improvements – a careful revision, preferably by a native English speaker, is strongly recommended.

Response: Thank you for your comments. According to your comment, the incorrect spellings and mistakes have been corrected. The sentences have also been revised.

Please find below list of remarks addressed to a specific fragment in the manuscript:

• Line 20: “In order to being sustainable development…” (English)

Response: According to your comment, the sentence has been revised.

• Line 23: “… by the reaction of biomass.” (English: maybe “…as a result of biomass decomposition”?)

Response: According to your comment, the sentence has been revised.

• Line 24: “…many uses…” (maybe many applications?)

Response: According to your comment, the phrase has been changed to “applications”.

• Line 39: a double space before “has been”

Response: According to your comment, the space has been removed.

• Line 48: “.” is missing after [2]

Response: According to your comment, the dot has been added.

• Line 48: “Due to…” (instead of “Because of…” – because is repeated)

Response: According to your comment, the phrase has been changed to “Due to”.

• Line 48: “… is becoming…” – I would suggest using present perfect continuous (not present continuous)

Response: According to your comment, the sentence has been changed to present perfect continuous.

• Line 57: “…enhance soil health.” (Maybe: “… improve soil quality”?)

Response: According to your comment, the phrase has been changed to “improve soil quality and fertility”.

• Line 70: a word “amendment” is not correctly used in this context

Response: According to your comment, the “amendment” has been changed to “supplement”

• Line 73: “large specific surface area…” – repeated (and no range of value provided)

Response: According to your comment, the repeated sentence has been removed.

• Line 83: “.” Dot missing at the end of sentence

Response: According to your comment, the dot has been added.

• Line 139: “weave features” - ??? (English)

Response: According to your comment, the “weave” has been removed.

• Line 154: “low porosity” – please provide figures for low and high values (which are satisfactory and expected for sorbents)

Response: According to your comment, some data has been added to the paragraph.

• Lines 164-165: wors “modification” used 3 times, “efficiency” 2 times in a single sentence

Response: According to your comment, the sentence has been revised.

• Line 205: “we discover” (impersonal, and past tense)

Response: According to your comment, “we discover” has been changed to “it was discovered”

• Line207: a word “qualities” is not correctly used in this context

Response: According to your comment, the “qualities” has been changed to “properties”.

• Line 245: a space is missing before “Richardson’s…”

Response: According to your comment, the space has been added.

• Line 273: “…and freeze-thaw cycles procession” (English – maybe “f-t processing cycles”?)

Response: According to your comment, the phrase has been changed to “freeze-thaw processing cycles”.

• Line 278: “It was found…” (was missing)

Response: According to your comment, the “was” has been added.

• Line 279: :The BET of processed biochar…” – The BET area (or BET spec. surface area)

Response: According to your comment, the “area” has been added.

• Line 280: “…more than before” (English + not clear before what?)

Response: According to your comment, the phrase has been changed to “more than before the ordinary biochar”.

• Line 280: the capacity is a parameter – it can increase (the process can be intensified or enhanced)

Response: According to your comment, the “enhance” has been changed to increase.

• Line 286: what are “difficult organic substances”?? (English)

Response: According to your comment, the phrase has been changed to “some hard-to-treat organic substances”.

• Line 292: Printing (lower case “p” in the sentence)

Response: According to your comment, the P has been changed to p.

• Line 293: not clear “biochar materials are always used in parallel with adsorption, catalytic, and degradation” (English – I guess maybe the Authors meant “…biochar mat. are usually used in and integrated process including (or combining) ad, cat, deg”)

Response: According to your comment, this paragraph was reorganized as followed:” On the other hand, for the treatment of printing and dyeing wastewater or organic matter, biochar materials are always used in and integrated process combining with adsorption, catalytic, and degradation”.

• Line 296: Biochar (lower case “b” here)

Response: According to your comment, the B has been changed to b.

• Line 297: “…treatment d.” (an editing mistake)

Response: According to your comment, the d has been removed.

• Line 298: water or wastewater?

Response: According to your comment, the word has been changed to wastewater.

• Line 306-307: English

Response: According to your comment, this paragraph has been reorganized as followed:” In this context, environmentally friendly wastewater treatment methods are better in order to achieve the goal of sustainable development.”.

• Line 309: “…a greater production cost advantage…” ?? (not clear)

Response: According to your comment, the sentence has been changed to “has a cost advantage”.

• Line 314: “…increase the settling.” (English)

Response: According to your comment, the “settling” has been changed to “the amount of sedimentation”.

• Line 314-315: repeated the same information as in Lines 313-314

Response: According to your comment, the repeated sentences has been removed

• Line 314: “.” (Dot missing after “settling”)

Response: According to your comment, dot has been added to the sentence.

• Line 320: “…good for increasing soil fertility after wastewater treatment” ??? (maybe you should add “…when dewatered digested sludge containing biochar is discharged into environment”?)

Response: According to your comment, “…when dewatered digested sludge containing biochar is discharged into environment” has been added to this paragraph.

• Line 340: This sentence is more relevant to chapter 4.3

Response: According to your comment, this paragraph has been reorganized.

• Line 356: please revise this “FeSO4-7H2O at pH 5.0. of FeSO4-7H2O”

Response: According to your comment, the sentence has been revised.

• Line 365: Shengquan (upper case letter)

Response: According to your comment, the spelling has been corrected.

• Line 368: lakshmi’s team… (upper case letter) – and I have not found this name in the References ([98] is Lingamdinne et al.)

Response: According to your comment, the references information has been corrected.

• Line 382: “… oil development” ?? (English)

Response: According to your comment, the phrase has been changed to petroleum development process

• Line 391: “limelight” ?? (En)

Response: According to your comment, the word has been changed to spotlight.

• In chapter 4.4: Rhodamine B is upper case in lines 398 and 400, and lower case in 403

Response: According to your comment, the spelling has been corrected.

• Line 432: “… can be tried” (En)

Response: According to your comment, this sentence has been deleted.

• Conclusions: Please indicate clearly what has already been achieved and published, and what technologies are at the development stage (please try to be more specific – when not achieved, please rate the developments level and achieved results if they are near or still far from expected/satisfactory results or if there are prerequisites/premises for achieving them)

Response: Thank you for your comments. This section has been revised.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript entitled ''Porous biochar materials for sustainable water treatment: synthesis, modification, and application'' is a good review article with an interesting subject and well-written context from scientific and English aspects. But there is one point about the background of research and used references. Some paragraphs have outdated references and some long paragraphs are left just with one reference. I think with some rephrasing and corrections authors can improve the text. Also, some important points are mentioned in the pdf. 

Good luck!

Comments for author File: Comments.pdf

Author Response

COMMENTS FROM THE EDITOR AND/OR REVIEWERS

Reviewer #2: The manuscript entitled ''Porous biochar materials for sustainable water treatment: synthesis, modification, and application'' is a good review article with an interesting subject and well-written context from scientific and English aspects. But there is one point about the background of research and used references. Some paragraphs have outdated references and some long paragraphs are left just with one reference. I think with some rephrasing and corrections authors can improve the text. Also, some important points are mentioned in the pdf.

Response: Thank you for your comments. Some new references were added to the review.

Abstract is clear and well figured out the whole paper. But it would be better to bring some values and numbers in percent. It would be nice to figuring out your reviewing between literature with some %. It's just a suggestion, but I think it makes your abstract more interesting.

Response: Thank you for your comments. Some literatures about biochar’s characteristics and properties were quoted in the review.

Please rephrase this sentence and delete ''more and more''!

Response: According to your comment, “more and more” has been deleted, and the sentence has been revised.

This paragraph definitely needs to be improved. biochar is your main subject. So it needs to give readers a compensative view of that based on literature. As a suggestion this paragraph should be go threw this way step by step: 1) what is biochar 2) Its special characteristics 3) its applications and benefits in ecosystems (environment, agriculture, GHG emission and soil-water purification) 4) which research were done and which remain 5) Your work wants to answer to those remain.

It would be simple to draw out your innovative of research and novelty. So please rephrase this paragraph as your key paragraph and bring some related references here. There are some: https://doi.org/10.3390/plants11111424 and https://doi.org/10.3390/agronomy12092106

Response: According to your comment, the paragraph has been revised and the reference has been quoted.

Please rephrase this sentence. Today there are too many published works that realized biochar-soil interactions. So the first part of the sentence is NOT true.

Response: According to your comment, the incorrect part of this paragraph has been deleted.

Like what? Bring some reference related to biochar effectiveness as a soil amendment and water improver. Here are some you can add them: https://doi.org/10.3390/w14213506 and https://doi.org/10.1007/s10333-022-00912-8

Response: According to your comment, the reference has been quoted.

Add this reference here: https://doi.org/10.3390/su142214722

Response: According to your comment, the reference has been quoted.

the correct form of this unit is: (°C min-1) -> -1 in superscript

The correct form of scientific unit is: mg g-1 Check it across the text.

Response: According to your comment, the form of unit has been corrected.

Mentioned references in some paragraph like this one are too low! You brought too many information just with one reference (13). So bring some new references related to your claims. Here is a new published work about modification techniques. Add this one also: https://doi.org/10.1002/ldr.4464

Response: According to your comment, the paragraph has been revised and the reference has been quoted.

Make sure about reference style into the text. There is NO need to mention author name and number of reference both! Just ref number should be.

Response: According to your comment, the form of references has been quoted.

Converting sewage sludge to biochar also is one of new approaches in sludge disposal managements. Bring some information related to that at the end of this paragraph. Here is one paper that fits here and you can add it: https://doi.org/10.3390/ijerph191912983

Response: According to your comment, the paragraph has been revised and the reference has been added.

In conclusion you need to present your own finalized conclude. without mentioning any references! So my suggestion for this section is make it shorter, remove references and make it your own!

Response: According to your comment, the paragraph has been revised and the reference has been removed.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Revised manuscript is improved. Authors addressed almost all my comments.  There are still some minor language mistakes, but not very significant (which can be accepted in a scientific paper).