Activation of Peroxymonosulfate by Fe, O Co-Embedded Biochar for the Degradation of Tetracycline: Performance and Mechanisms
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear Authors, there are a few remarks, in my opinion you should read in order to improve the article.
Page 2 Line 90.
It's always important to write as a professional. Although you can often find wrong terminology even in high rated journals, it's better understood the initial meaning.
XRD - x-ray diffraction or powder x-ray diffraction method uses monochromatic radiation. According to IUCr (international union of crystallography) and according to general physics principles "spectra" means a variable wavelengths of radiation was used during experiments.
I'd advice to write "XRD pattern" or "powder XRD pattern" instead of "XRD spectra". Not only at the Line 90, but everywhere further in your work.
Page 2 Line 93.
The sentence "the presence of SiO2 crystals" sounds rather unclear. The most typical way to write would be, for instance, "the presence of Si-containing phase, ***name_of_the_phase*** (JCPDS or ICDD number) was confirmed...". Please, insert the correct phase identification name, e.g. alpha-quartz or another.
Page 3 Lines 112-115
Figure 2 shows SEM images of obtained materials but a scale bar is missing. Please, do insert scale bars to every image.
Page 4 Line 116
The description of Figure 2 is controversial or unclear. You should definitely explain what does it mean "the mapping images" correctly (I guess, it was EDS or EDX data). As far as you have got spectroscopy data, it's useful to add chemical composition information as a table with atomic ratio.
Lines 107-143
It is extremely crucial to know the actual chemical composition of the samples has been studied. You have performed an analysis, okay, please, provide the chemical composition as the results. If we do not know how much Fe or Si or O is there, how can we compare the materials? Please, improve this part of the manuscript carefully.
Page 11 Line 325
Please, specify the inert gas was used for pyrolysis and its flow rate if it was performed not in sealed tubes.
Page 11 3.4. Characterizations and analytic methods
You should briefly describe the all experimental procedures despite the fact it was already published before.
I hope the article will be published after a minor revision.
Best wishes
Author Response
请参阅附件。
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors describe the preparation of Fe,O-co-embedded biochar and their use in the degradation of tetracycline. This is an interesting piece of work that may deserve publication following answer to the following comments:
The XRD seemingly shows diffraction peaks for SiO2 crystals, is Si observed in SEM and XPS?
The fitting/deconvolution of the XPS Fe 2p region is questionable. It would be better to apply higher number of scans for this region to increase signal resolution. Similarly, the presence of a Fe-O peak in the O 1s region seems an artificial result of peak fitting/deconvolution…
Please use the same number of decimals for all the XPS binding energies mentioned.
In the text, the authors use both “adsorption” and “absorption”, which are two different phenomenon. Please correct accordingly.
For the clarity of discussion/reading, it would have been simpler that the relevant graphs represent the relative removal efficiency (C0-C)/C0 rather than the relative residual concentration of the species of interest (C/C0), especially because the removal/degradation efficiency is mainly discussed in the text (not the residual concentration).
Particle size distribution and physisorption data may bring valuable information to relate with the performances of the different tested materials. These analyses should be added to complete the characterization of the synthesized materials.
The authors should better describe the used greenness analysis and explain the factors that are considered. Does this analysis consider the highly energetic pyrolysis process used to prepare the BC? It sounds that this greenness analysis does not bring significant added value to the present work, and will not be missing if removed.
Yet, the leaching of Fe is an interesting observation. What is the initial Fe content measured in the synthesized materials? %leaching should be used in Figure 8b instead of “leaching of Fe”. Control experiments should also be performed to verify whether this leached Fe significantly contribute to the performance of the material.
Typos: please correct in the manuscript:
EPs vs Eps
Figure. nx to Figure nx
Pyrolysis vs pyrosis
English may also be improved
Comments on the Quality of English LanguageEnglish phrasing could be improved
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors discussed here the “Activation of peroxymonosulfate by Fe, O co-embedded biochar for the degradation of tetracycline: Performance and mechanisms”. Where they investigated the co-doping of Fe and O into biochar generated from corncobs to remove emerging pollutants (EPs) using tetracyclines (TCs) as the representative compound. Furthermore, an investigation was conducted on the variables that impact the pace of TC degradation, including the dosage of Peroxymonosulfate (PMS), the quantity of catalyst employed, the initial pH level of the solution, and the existence of coexisting anions. In addition, the active sites of the catalysts were further examined by comparison tests involving several catalysts. Scavenging tests were conducted to clarify the contributions of the active species and the degradation mechanism.
First of all, I think that this paper is, as a whole, scientifically sound and the topic is of wide interest. However, in my opinion, there are points that need to be clarified prior to publication:
1. Label the XRD peak at 27 degrees in figure 1a as you have done to all major peaks.
2. Fig 2 is not well correctly titled. The current tittle of fig.2 is confusing especial the labeling of mapping images that the authors call Fig2d. Moreover, the mapping image for Fe and N are not clear, or does it mean there are no Fe particles on the biochar? Moreover, the authors did not say anything in the discussion under SEM on the mapping images presented in Fig2d.
3. The authors present the results in figure 4a as the oxidation/degradation of the pollutant, however the results seems to represent the adsorption and may be oxidation of the pollutant on the doped biochar. There is no evidence that oxidation process has taken place during this investigation. It is likely that the adsorption alone has took place. The author must prove that the oxidation has took place here. If oxidation has took place, how about adsorption? The author did not mention adsorption, although the pore were observed in the SEM images.
4. Figure 7 results have demonstrated that both adsorption and oxidation processes took place. What is the adsorption capacity of the adsorptive material under study?
5. The procedure for the oxidation and greenness analysis are missed in the experimental procedures section.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsI have reviewed the revised manuscript and the author have answer all the question and did the corrections.
