Synthesis of Ce-La-Pr/Mn-O Ternary Oxide Composites via Co-Precipitation and Synergistic Photocatalytic Degradation of Cr(VI)
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis study employed a straightforward co-precipitation technique to successfully synthesize Ce-La-X(Mn/Pr)-O composite materials with distinctively porous and fluffy textures, along with tubular morphologies. These materials were subsequently employed for the treatment of simulated Cr(VI) wastewater. Notably, Ce-La-Mn-O demonstrated a remarkable specific surface area of 96.2698 m2 /g, mesoporous architecture with a pore diameter of 6.9511 nm, and an impressive adsorption capacity of 88.79 mg/g.Under optimized conditions, specifically an initial Cr(VI) concentration of 20 mg/L, a Ce-La-Mn-O dosage of 0.04 g, a reaction tem-perature of 40°C, an initial pH of 6, and illumination, the removal rate of Cr(VI) exceeded 98% within 15 minutes.
The manuscript is well organized and of great importance due to the significant contribution to the filed. It can be accepted after inserting the following minor comments and suggestions:
1. “Co-precipitation method” in the title.
2. Abstract is too long. Please shorten it with focus on the significant findings of your work.
3. Synthesis” is not a keyword in your work! Please reconsider them.
4. Wastewater treatment using the novel photocatalytic systems (making use of newly-released reports i.e. https://0-www-sciencedirect-com.brum.beds.ac.uk/science/article/abs/pii/S0925838820333193) should be highlighted in the general discussion of the introduction. The references can be update, as a whole.
5. Temperature of the reaction medium in subsection 2.4., should be mentioned.
6. Figure captions should be comprehensive, Fig. 2.
7. What about the result of dark test over the best sample with highest specific surface area?
8. Toxicity concerns of Cr species should be discussed more in the introduction.
good luck
Comments on the Quality of English Languageminor revision
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors have submitted a manuscript entitled “Synthesis of Ce-La-X(Pr/Mn)-O Ternary Oxide Composites by Co-precipitation and Synergistic Photocatalytic Degradation of Cr(VI)”. I would like to ask a few questions and provide a few suggestions.
The authors should provide a reference for the first statement of their introduction section.
The authors should carefully check for the subscript/superscript/acronym/abbreviation throughout this manuscript.
What is the significance of Mn/Pr doping into the composite. The author may include a discussion and importance of this.
On what basis the authors have chosen the stoichiometry of the precursors?
Why the higher calcination temperature of 500 is required for this sample as it is prepared by coprecipitation method?
Why there is “*” symbol in all the indexed planes. If there is no significance, the authors may remove that.
In page 6, the authors have written as “The SEM observations and microstructural analyses of Ce-La-Mn before and after Cr(VI) removal are presented in Figure 5.” However, the same seems to be different from the given discussion as shown in figure caption.
There is a drastic change in the particle size of the sample after Pr and Mn doping as observed from figure 5 b and c. The authors may extract the particle size distribution and discuss more on that.
The authors discussed pores in the SEM discussion which is not relevant as the pores can not seen from the micrograph. If discussion is needed, then the authors may provide high-resolution micrographs.
Why there is a fan in the chromium removal experiments. The authors may provide detailed procedure of Chromium removal in the experimental section. What will happen if there is no light. Did the authors check for the results.
Which sample is used for the results in figure 8. The sample details should be included.
Why only one sample is given in Figure.11. it may be moved to supplementary.
In Figure 15, the authors have provided a porous structure which was not observed from any of the morphological analysis. The authors should prove the structure or remove that diagram.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsIn this work, Xiujuan Feng et al. reported the “Synthesis of Ce-La-X(Pr/Mn)-O Ternary Oxide Composites by Co-precipitation and Synergistic Photocatalytic Degradation of Cr(VI)”. This study showcases the synthesis of Ce-La-X(Mn/Pr)-O composite materials using a co-precipitation method, which resulted in unique porous and fluffy textures with tubular morphologies, tailored for Cr(VI) wastewater treatment. The Ce-La-Mn-O variant stood out, featuring a high specific surface area of 96.2698 m²/g, mesoporous structure with a 6.9511 nm pore diameter, and an impressive 88.79 mg/g adsorption capacity. Under specific conditions, it achieved over 98% Cr(VI) removal within 15 minutes and maintained an 80% efficiency after three usage cycles. The addition of Mn/Pr modified the Ce-La-O structure, enhancing metal synergy and introducing -OH polar bond functional groups, effective in reducing Cr(VI) to less harmful Cr(III), demonstrating potential for practical water treatment applications.
Based on these following findings, I do not think the manuscript could be considered for publication in “Water”.
1. The editor pointed out the issue of wording duplication. It's essential to revise and explain this.
2. There are instances of incomplete citation formats in the manuscript.
3. In the introduction section, it is recommended to include a motivation for why Mn and Pr were chosen to be doped into the catalysts.
4. In Fig. 3, I suggest to introduce FWHM to describe the change of diffraction intensity. And can authors find literature support for the explanation of displacement?
5. In Table 1, the data in the last column do not seem to match Fig. 4b.
6. Are the images of Fig. 5 before or after 191 Cr(VI) removal? This does not match the relevant content.
7. The manuscript lacks logical flow and organization, with some content that should appear earlier found in later sections. Reorganize the manuscript to improve its logical progression, ensuring that readers can easily follow your research story. Additionally, standardize the visualization style of data and images for a cohesive appearance.
8. Concerns were raised about the accuracy of some data analyses, such as the R2 values in Fig. 9b. Reevaluate your data analysis to ensure accuracy.
9. I disagree with your judgement of the gap value, noting absorption beyond 800nm for Ce-La-Mn, suggesting a lower gap.
10. Question the relevance of including SEM images in Fig. 15 at the current location in the manuscript.
Comments on the Quality of English LanguageModerate editing of English language required.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsThe manuscript presents a straightforward co-precipitation technique to successfully synthesize Ce-La-X(Mn/Pr)-O composite materials with distinctively porous and fluffy textures, along with tubular morphologies. In parallel, the Ce-La-Mn-O materials exhibited superior visible light absorption properties and dual functionality for catalytic reduction and adsorption. Furthermore, it explores and discusses the composite material, the morphology, valence state, element distribution, and content to evaluate the reaction mechanism. These findings offer a robust theoretical foundation for exploring the dual functional synergistic effects in the efficient removal of Cr(VI) from aqueous systems. The comprehensiveness and depth of this manuscript make it suitable for publication in Water. Therefore, I believe the manuscript could be accepted after some revisions. The specific suggestions are listed as follow:
1. In the introduction section, providing additional details and current examples (since 2022) of other top catalysts similar to this work reported in top-tier journals would enhance the manuscript's quality.
2. Please add the legend of the figures 8c and d.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsThe author basically addressed the issues I raised and I have no further comments on the current version. I think it could be considered for publication.
