Thermodynamic Investigation and Study of Kinetics and Mass Transfer Mechanisms of Oily Wastewater Adsorption on UIO-66–MnFe₂O₄ as a Metal–Organic Framework (MOF)

Round 1

Reviewer 1 Report (Previous Reviewer 2)

Thank you very much for your effort 

 

Author Response

Reviewer 1

Comment 1: Thank you very much for your effort.

Answer:

Thank you very much for your kind comment and efforts toward improving our manuscript.

Author Response File: Author Response.docx

Reviewer 2 Report (Previous Reviewer 1)

The authors have improved the manuscript, the manuscript can be accepted for publication. However, the Figures of FTIR and XRD study should be improved more. and must be drawn professionally. 

Author Response

Reviewer 2

Comment 1: The authors have improved the manuscript, the manuscript can be accepted for publication. However, the Figures of FTIR and XRD study should be improved more. and must be drawn professionally.

Answer:

Thank you for your comment. The comment was applied and the FTIR and XRD images were improved, and the main peaks also were marked. To present the FTIR and XRD results the following articles were applied:

• Nasehi et al. “Synthesis of novel acid-promoted UIO-66-NH2-MnFe2O4-TiO2- TiNT nanocomposite for high synchronous adsorption of cadmium and methyl orange and conditions optimization by response surface methodology”, Separation Science and Technology, Volume 56 (5), 2021
• Zhanget al. “TiO2-UiO-66-NH2 nanocomposites as efficient photocatalysts for the oxidation of VOCs” Chemical Engineering Journal, Volume 385, 2020

Author Response File: Author Response.docx

Reviewer 3 Report (New Reviewer)

1. The particles sizes for UIO-66-MnFe2O4 MOF sample should be counted. Also, please provide the EDX.

2. In Fig. 2 and 3, please mark the main peaks in the map.

3. Please provide the BET data for the UIO-66-MnFe2O4 and UIO-66.

4. In this part, “The MOFs which are synthesized by coordination bonds between metal ions/clusters and organic ligands, have attracted much attention due to their high porosity, high chemical and thermal stability, and the ability to adjust their structure and application” some updated and new work could be highlighted, such as Inorg. Chim, Acta 546(2023)121297; Micropor. Mesopor. Mat, 341(2022) 112098; Inorganics, 10(2022) 202; Mater. Today. Commum., 2022, 31,103514 and Dalton Transactions, 2022, 51, 14817-14832.

5. The structural stability should be confirmed by the morphology of samples after multiple adsorption tests.

6. Since pharmaceuticals and personal care products have huge production with extensive usage as well as frequently detected in surface water and ground water. How can the adsorbent be put into the underground water? How to control costs?

Author Response

Reviewer 3

Comment 1: The particles sizes for UIO-66-MnFe2O4 MOF sample should be counted. Also, please provide the EDX.

Answer:

Thank you for your comment. The EDX results are presented in Table 2. As mentioned in line 303-304, the results show that the particles sizes of UIO-66-MnFe2O4 MOF crystals are varying from 8 to 23 μm.

 

Comment 2: In Fig. 2 and 3, please mark the main peaks in the map.

Answer:

Thank you for your comment. The comment was applied and the FTIR and XRD images were improved, and the main peaks were marked.

 

 

Comment 3: Please provide the BET data for the UIO-66-MnFe2O4 and UIO-66.

Answer:

Thank you for your comment. The values of 783 m²/gm and 1061 m²/gm were obtained using BET for the surface area of the obtained UIO-66-MnFe2O4 MOF and UIO-66 respectively which is mentioned in Line 296-297.

 

 

 

Comment 4: In this part, “The MOFs which are synthesized by coordination bonds between metal ions/clusters and organic ligands, have attracted much attention due to their high porosity, high chemical and thermal stability, and the ability to adjust their structure and application” some updated and new work could be highlighted, such as Inorg. Chim, Acta 546(2023)121297; Micropor. Mesopor. Mat, 341(2022) 112098; Inorganics, 10(2022) 202; Mater. Today. Commum., 2022, 31,103514 and Dalton Transactions, 2022, 51, 14817-14832.

Answer:

Thank you for suggesting these articles. The comment was applied and the mentioned articles were used to enrich the literature review section and were cited.

 

Comment 5: The structural stability should be confirmed by the morphology of samples after multiple adsorption tests.

Answer:

Thank you for your comment. Yes, you are right, in order to study the structural stability, the morphology of samples after multiple adsorption tests should be confirmed. Nevertheless, the aim of this work was to investigate the mass transfer mechanism and to study the kinetic models in the adsorption process of oily wastewater treatment using MOFs. In this way, after the synthesis of the MOF, adsorption tests were performed on oily wastewater to analyze the obtained experimental data. Since the aim of this work was not to investigate the structural stability of synthesized MOF, therefore the morphology of the samples was not studied after multiple adsorption tests. However, this is a good suggestion for the future works to investigate the morphology of samples after multiple adsorption tests to confirm the structural stability.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report (New Reviewer)

accept

Author Response

Thanks for your comments and suggestion 

Author Response File: Author Response.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments on sustainability-2061313

Dear Sir/Madam,

The manuscript “Thermodynamic Investigation and Study of Kinetics and Mass Transfer Mechanisms of Oily Wastewater Adsorption on Zr6O4(OH)4-MnFe2O4 as a Metal-Organic Framework (MOF)” seems like a report of an experimental work. Although the authors have tried to collect various techniques and models to elaborate the study but it’s in random order and no scientific planning of the work is performed. Therefore, it is not suitable to represent the study for publication. (Major)

Comment 1: Check the whole manuscript for typing errors and check for grammatical mistakes throughout the text. For example; abstract Line 25-27 the used language is not appropriate for abstract please follow some good impact factor papers.

Following studies may be helpful; Fuel, 2021; 291, 120133, Bioresource Technology, 2013; 135, 690-696.

Comment 2: Abstract: The abstract only contains some parameters without any process conditions or key values from results, which is insufficient to delineate the whole picture of the contribution and possible application of this study. It is suggested to add some background with a few objectives, key values from the results, and possible applications of this study and highlight the novelty of this work clearly.

Comment 3: Add more information to rearrange the Introduction's last paragraph as; present a summary of the above literature review, research gaps should be highlighted in comparison with the literature review. Explain, how this study is different from others? The novelty of this study should be mentioned here.

Comment 4: Materials and Methods: Line 158: Use standard units to present such as use gm instead of using gr. Some chemical names/formulas are missing/incomplete or the method is not supported by the literature, please carefully check and revise.

Line 163-184 the common synthesis method of MOFs are discussed, this section is not appropriate to discuss this. I suggest to move them to Introduction and Literature review section. In Materials and Method section only standard procedures with some references can be used.

Comment 5: Line 246 remove word which it is inappropriate to use it.

Comment 6: The characterization section is also week in light of literature.

Comment 7: The graphs and figures throughout the manuscript are not consistent and professionally drawn, some with blurry resolution. For example, XRD, SEM and FTIR figures are very unprofessional. Revise all graphs with high-quality images and keep all figures as colored with consistent fonts. The units stated in the graphs axis need to be double-checked.

Comment 8: Line 365-387 no single reference is cited, similarly the whole manuscript does not cite references, which is a killing mistake…Following studies may be helpful; Fuel, 334, 126798. Bioresource Technology, 2011;102 (17):8003-10.

Comment 9: Revise all Tables, see some high-impact published papers to organize information.

Comment 10: Line 392-396: The pseudo-first-order model with R²=0.989 is followed. However, Elovich models with R²= 0.961, is also closer to the y=x line. What are the reasons that first order model is followed also no references of the previous study are given. Same issue is observed in the whole manuscript i.e. Weber and Morris, liquid film penetration model and Bangham and Burt model.

Comment 11: Authors have tried to study adsorption, using standard models but the screening experiments were not performed to proceed with the study. The whole modeling section quotes no references. It seems that authors have copied the models and applied them without any further verifications.

Comment 12: The conclusions only talk about some studied parameters, which is insufficient to depict the whole picture of the contribution of this study. The authors are advised to write the conclusions comprehensively and should contain key values, suitability of the applied method, the major findings, contributions and possible future outcomes (250-300 words).

Comment 13: The highlights are not satisfactory as only synthesis is performed. This paper is just a study of parameters and a blend of models being used. No verification and authentication of models and mass transfer phenomenon is performed in light of literature.

 

Thank You

Comments for author File: Comments.pdf

Reviewer 2 Report

1-     The "conclusion and the key results " in the abstract part must be improved.

 

2-     What are the main properties of Metal-Organic Frameworks (MOFs)?

3-     Add a comparative study table based on the literature review

4-     The literature assessment section can be enriched with recent and relevant works. Following articles may become useful to authors. https://doi.org/10.1063/5.0000157 , https://doi.org/10.5004/dwt.2022.27986 , https://dx.doi.org/10.21608/ejchem.2020.11981.1752

5-     Is the surface area appropriate for this application? The author must discuss this point in detail because the surface area is very important factor.

 

Reviewer 3 Report

The author talked several times about what is MOF and what are the merits of MOFs. At the same time, in the introduction section, the author said ”(MOF has) high chemical and thermal stability”, however, the author said merely 5 lines below: ”metal-organic frameworks show relatively little stability”. It seems the author did not know what they are writing.

 

Significant English editing is required with many grammar issues. The author also discussed too much irrelevant content (for example, solvothermal or non-solvothermal discussion). Also, the arrangement of the discussion is poor.

The author named “Zr6O4(OH)4-MnFe2O4”, however, BDC, the organic part was not mentioned. Something like UiO-66-MnFe2O4 should be mentioned instead.

The author did not describe how the adsorbed amount was calculated. At the same time how other experiments were done was also not clearly described.

In figure 5, when the initial concentration is higher than 800uM, the removal percentage remained relatively constant. This is against the author’s claim that it reaches saturation. As the same percentage here means increasing adsorbed amount.

Figure 6 describes the kinetics of different concentrations the axes were not labeled. And the result was not fully discussed.

In figure 7, the author said, “All cases show a decrease in adsorption with an increase in temperature”, but temperature is not a variable in the figure or different lines. The legend also gives no unit. This is very unprofessional.

Figure 9 was the first time the author included any kinetic data. but the author has discussed the linear regression in table 1. I don’t see how that was done.

Figure 10 has no unit. And the author did not describe what was the initial concentration.

Figure 12. temperature is described as K. this is wrong. It should be degree C.

The performance was not compared to other materials.