Adsorption of Atrazine by Fe-Mn-Modified Biochar: The Dominant Mechanism of π–π Interaction and Pore Structure
Round 1
Reviewer 1 Report
Recently published research should be added to the introduction and results parts.
English editing.
Author Response
I appreciate you for offering us an opportunity to revise our manuscript. The comments and suggestions raised by you are valuable and thoughtful. We carefully revised the manuscript and made the point-to-point response to each comment or suggestion. To help you see clearly, all responses to the comments and revisions in the text are highlighted in blue.
Author Response File: 
Author Response.docx
Reviewer 2 Report
In my opinion, a good abstract should include a few sentences on the justification of this research, but also on the methodology followed. In this case, most of the abstract is devoted to the results and discussion, but I consider it more appropriate to reduce a few lines on the results and include a few sentences on the introduction and the material and methods.
In the abstract, please correct the chemical formulae for correct spelling of supers and subscript numbers.
In section “2.5. Effect of pH on adsorption experiments” reads:
“0.1g of biochar or modified biochar was added to 40 mL atrazine solution (10 mg·L-1), and the initial pH of the solution was adjusted to 3.0, 5.0, 7.0, 9.0 and 10.0 by 0.1mol·L-1 HCL and NaOH, respectively. The solution was shaken in a 150r/min shaker at 25℃ for 24h under dark conditions. The following steps are the same as the adsorption kinetic conditions. To explore the influence of pH on the adsorption of atrazine by biochar.” Please leave a blank space between some figures and their units, e.g. "150 r/min, 25 ℃, 24 h". Please extend it to the rest of the manuscript.
The manuscript reads: "3.7. adsorption mechanism". Please start the first word with a capital letter: "3.7. Adsorption mechanism".
In the main body of the manuscript there are citations to Fig.5, Fig.6, Fig.7 and Fig.8, but these figures have not been included in this paper. Please review this issue.
In the main body of the manuscript there are citations to Figure S2, but this figure has not been included in the supplementary materials. Please review this issue.
The supplementary materials include Table S3, but this table has not been cited in the text of the manuscript. Please review this issue.
At the end of the article, the sections "Funding:", "Data availability statement:" and "Conflicts of interest:" must be duly completed.
Author Response
Dear reviewer,
I appreciate you for offering us an opportunity to revise our manuscript. The comments and suggestions raised you are valuable and thoughtful. We carefully revised the manuscript and made a point-to-point response to each comment or suggestion. To help you see clearly, all responses to the comments and revisions in the text are highlighted in blue.
I would like to thank you again for your time and effort in handling our manuscript and hope that all revisions are satisfactory.
With my best regards,
Yuan Liang
Corresponding author
Author Response File: Author Response.docx
Reviewer 3 Report
Comments to authors:
I have revised your manuscript entitled “Adsorption of Atrazine by Fe-Mn modified biochar: The dominant mechanism of π-π interaction and pore structure” This is a very interesting topic. But, this manuscript is full of contradictions. The authors must find rational explanations for these discrepancies. Many Figures are absent from the manuscript. Here are my comments.
Introduction
· Line 31: “low adsorption on soil” Why is the adsorption of Atrazine in the soil is low?
· Line 33: “90%” What does this percentage represent?
· Write about some of the chemical properties of atrazine
Materials and methods
· Line 71-76: After soaking biochar with four molar ratios of Fe2+ and Mn2+ Was the produced modified biochar washed?
· Where is the statistical analysis used in this manuscript?
Results and discussion
· Line 155: correct “ketomes” to “ketones”.
· Line 202: what the relation between Zeta potential and zero charge (pHpzc).
· Discussion is weak throughout most of the manuscript
· Fig.S2 does not exist.
· What is the charge of atrazine?
· Line 208-210: “the surface of original biochar and 4 Fe-Mn modified biochar was negative, which is not conductive to the adsorption of atrazine by original biochar and modified biochar because of electrostatic repulsion” and Line 211-214: “Compared with DBC, the negative of Zeta potential for modified biochar decreased at the same pH, indicating that the decrease of electrostatic repulsion between atrazine and modified biochar and increase the atrazine adsorption on modified biochar”.
There is a contradiction between these two sentences regarding the repulsion forces acting.
· Line 219: The authors did not use Elovich kinetic model in this study.
· Line 246: “the faster adsorption speed of modified biochar on atrazine” this sentence is an error because the atrazine was adsorbed on biochar surfaces.
· Table S2 is an error because It does not contain Freundlich and Langmuir models
· Figure 5 is missing
· Lines 267-269: “No significant changes of Qe for modified biochar at pH 3-11 were observed indicated that the atrazine adsorption of modified biochar was not pH-dependent” This is a mistake. Because the charges that are mainly on the biochar are of the type of pH-dependent charge or variable charge.
· Line 271: In fact, when the pH is less than 7, the positive charges prevail on the surfaces of the biochar, while when the pH is greater than 7, the negative charges prevail on the surfaces of the biochar.
· Lines 269-285: “Therefore, the interaction between biochar and atrazine should be electrostatic repulsion.” There is a contradiction here with the fact that atrazine has adsorption on the surface of the biochar as described in 3.3. Adsorption kinetics and 3.4. Adsorption isothermal
· Figure 6 is missing
· 3.6. Desorption capacity: in this section the decreasing desorption process, this is evidence of adsorption.
· Figure 7 is missing
· Figure 8 a,b are missing
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Author Response
Dear reviewer,
I appreciate you for offering us an opportunity to revise our manuscript. The comments and suggestions raised you are valuable and thoughtful. We carefully revised the manuscript and made a point-to-point response to each comment or suggestion. To help you see clearly, all responses to the comments and revisions in the text are highlighted in blue.
I would like to thank you again for your time and effort in handling our manuscript and hope that all revisions are satisfactory.
With my best regards,
Yuan Liang
Corresponding author
Author Response File: Author Response.docx
Reviewer 4 Report
The paper ''Adsorption of Atrazine by Fe-Mn modified biochar: The dominant mechanism of π-π interaction and pore structure'' is investigated on atrazine fixation affected by a modified biochar medium. The paper has been well written. methods and discussion well described. However background of research needs to be extend a little. Please see some suggestion below:
line 13: improved the its removal---> ''the'' should be removed.
line 13: F3M1DBC-----> This is the first time that you are using this abbreviation. Before that you MUST define it. All abbreviation should be defined before presenting! Check it all across the text.
line 44: useful to improv the----> ''improve''
Introduction is to short and needs to be improve in background of research. For instance bring some general information about various types of biochar-modification techniques (application of chemical solutions, steams, exposing clay particles....) and then give readers why Fe/Mn oxides were your choose. Here is a new publication that fits in your scope:
http://dx.doi.org/10.1002/ldr.4464
line 70: original rice straw-derived biochar, named as DBC.----> What is ''D'' represent for? Moreover, your treatments have a long name! It would be better if they were shorter. Just simply say ''B'', that would be fine for biochar.
Please check references style!
Author Response
Dear reviewer,
I appreciate you for offering us an opportunity to revise our manuscript. The comments and suggestions raised you are valuable and thoughtful. We carefully revised the manuscript and made a point-to-point response to each comment or suggestion. To help you see clearly, all responses to the comments and revisions in the text are highlighted in blue.
I would like to thank you again for your time and effort in handling our manuscript and hope that all revisions are satisfactory.
With my best regards,
Yuan Liang
Corresponding author
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
Thank you for recommending a response to all comments
