Influence of Magnetic Field on Atrazine Adsorption and Degradation by Ferroxite and Hematite

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Marcos A. Sousa et al. reported the effect of magnetic field on ferrite and hematite in atrazine degradation and adsorption. The results showed that the magnetic field enhanced the degradation and adsorption efficiency of ferrite, while the effect on hematite was small, which provides a new idea for the field of environmental remediation. The paper may be considered for publication by Magnetism if the authors can address the following questions.

1. Please check the formatting of the manuscript carefully; the section headings do not correspond at all, and the subheadings in section 3 are all the same. Where is section 4?
2. It is recommended that the explanation of enhanced adsorption by magnetic fields be added.
3. Please add information about the magnetic field. Magnetic field intensity and its effects? Does the direction of the magnetic field have an effect? Constant or alternating magnetic field?
4. It is recommended to refer to some of the literature on magnetic field-enhanced catalysis for a more in-depth explanation of why magnetic fields can enhance degradation rates.

Author Response

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Revisor 1:

Comments and Suggestions for Authors:

 

Marcos A. Sousa et al. reported the effect of magnetic field on ferrite and hematite in atrazine degradation and adsorption. The results showed that the magnetic field enhanced the degradation and adsorption efficiency of ferrite, while the effect on hematite was small, which provides a new idea for the field of environmental remediation. The paper may be considered for publication by Magnetism if the authors can address the following questions.

• Please check the formatting of the manuscript carefully; the section headings do not correspond at all, and the subheadings in section 3 are all the same. Where is section 4?

A: We sincerely thank the reviewer for identifying these formatting inconsistencies. Upon careful review, we confirmed that there were indeed errors in the numbering and consistency of the section and subsection headings. In the revised manuscript, we have corrected all section and subsection numbers to ensure logical progression (e.g., 1. Introduction, 2. Materials and Methods, 3. Results and Discussion, 4. Conclusions), and revised subsection titles within Section 3 to reflect specific contents and corrected conclusion as section 4, which was missing due to formatting. Additionally, we have also ensured consistent formatting throughout the manuscript in compliance with the journal’s guidelines.

 

 

• It is recommended that the explanation of enhanced adsorption by magnetic fields be added.

A: We thank the reviewer for this insightful recommendation. In the revised manuscript, we have incorporated a dedicated explanation of the potential mechanisms by which an applied magnetic field enhances adsorption. In light of some of the possible physicochemical processes that could explain the increased adsorption efficiency induced by magnetic field application, we have added a concise discussion of these points in the manuscript and supported them with relevant references from recent literature. (Page 8, lines 283-317).

 

 

• Please add information about the magnetic field. Magnetic field intensity and its effects? Does the direction of the magnetic field have an effect? Constant or alternating magnetic field?

 

A: We sincerely thank the reviewer for the insightful comments and the opportunity to clarify these important aspects of our study. In response, we have revised the manuscript to include comprehensive details regarding the magnetic field parameters. Specifically, we now report the intensity of the applied magnetic field, the method used for its application to the sample, and the rationale for selecting the exposure durations of 0.1 and 2 hours. These details have been incorporated into the revised version, particularly in the “Materials and Methods” section, subsection 2.6 titled “Determination of values for Fenton analyses by means of removal by adsorption.”

In addition, we have expanded the discussion to address the effects of the magnetic field on the adsorption/desorption process and to consider the potential for field-dependent behavior. We fully acknowledge the reviewer’s suggestion and agree that a more in-depth analysis of field-dependent adsorption/desorption would be valuable. Therefore, we have explicitly recommended this direction for future studies in the revised “Results and discussion” section.

We are grateful for the reviewer’s valuable feedback, which has contributed significantly to enhancing the clarity and scientific rigor of our manuscript

 

 

• It is recommended to refer to some of the literature on magnetic field-enhanced catalysis for a more in-depth explanation of why magnetic fields can enhance degradation rates.

A: We appreciate the reviewer’s insightful suggestion to include a more detailed discussion of magnetic field-enhanced catalysis mechanisms. In response, we have expanded the manuscript to incorporate recent high-impact studies elucidating how magnetic fields can influence catalytic performance, particularly in degradation processes. In fact, several studies have shown that magnetic fields can affect catalytic systems via multiple pathways, including spin state modulation, magnetothermal effects, and magnetohydrodynamic forces. Accordingly, we have revised the discussion section to include these insights and have cited the relevant literature to better support our findings and clarify the role of magnetic fields in catalytic degradation systems.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The correlation between magnetic field induction and the efficiency of adsorption and desorption processes appears intriguing; however, detailed magnetic analyses are lacking. Additionally, the underlying mechanism governing the influence of the magnetic field on these processes is not thoroughly discussed, which is important for the journal "magnetism"

1. There are no details about the magnetic field. What is the value of the applied field? It says it controlled the magnetic field for 0.1 and 2 hours. What is the intensity of the field? How does the duration affect the process? And how was the magnetic field applied to the sample?
2. Also, a field-dependent adsorption/desorption process would be recommended
3. If the ferroxide interacts with the pollutant, what is the interaction mechanism? It is jot discussed well. 
4. Is it possible to perform in-situ magnetic field application of the adsorption/desorption process?
5. Again, the following sentence does not say the mechanism or clear magnetic phenomena behind the process. And no reference for such phenomena. "in the presence of a magnetic field suggests that the application of the magnetic field may enhance the interaction between Ferroxite and Atrazine, possibly by promoting better dispersion of the adsorbent or altering the surface properties of Ferroxite, thereby increasing its efficiency in adsorbing Atrazine.
6.  How do antiferromagnetic properties prevent?  "antiferromagnetic 235 properties prevent the field from significantly altering its behavior, limiting the 236 enhancement of adsorption."
7. Where is the reference that the duration of the magnetic field could alter the adsorption/desorption properties?
8. No magnetic studies have been done on the absorbent during any process.
9. The entire work does not have any relevent magnetic studies. A strong proof of magnetic experiments is required
10. What are the possible magnetic techniques that could complement/support the manuscript?

Author Response

The correlation between magnetic field induction and the efficiency of adsorption and desorption processes appears intriguing; however, detailed magnetic analyses are lacking. Additionally, the underlying mechanism governing the influence of the magnetic field on these processes is not thoroughly discussed, which is important for the journal "magnetism"

 

 

1. There are no details about the magnetic field. What is the value of the applied field? It says it controlled the magnetic field for 0.1 and 2 hours. What is the intensity of the field? How does the duration affect the process? And how was the magnetic field applied to the sample? Also, a field-dependent adsorption/desorption process would be recommended.

A: We appreciate the reviewer’s insightful comments and the opportunity to clarify these important aspects of our work. In response, we have revised the manuscript to include detailed information regarding the magnetic field parameters. Specifically, we have now included the intensity of the applied magnetic field, the method of application to the sample, and the rationale behind the selected exposure durations (0.1 and 2 hours). These additions can be found in the revised version under the “Materials and Methods” section, and 2.6 subsection “ Determination of values for Fenton analyses by means of removal by adsorption”. Furthermore, we have expanded the discussion to address the influence of magnetic field on the adsorption/desorption process and have considered the potential for field-dependent behavior. We acknowledge the reviewer’s suggestion, and we agree that a more comprehensive analysis of field-dependent adsorption/desorption is valuable; accordingly, we have included this as a recommendation for future work in the “Results and Discussion” section. Thank you again for your valuable feedback, which has helped to strengthen the clarity and depth of the manuscript.

 

 

 

 

2. If the ferroxide interacts with the pollutant, what is the interaction mechanism? It is jot discussed well.

 

A: We sincerely thank the reviewer for this valuable and insightful recommendation. In response, we have revised the manuscript to include a dedicated explanation of the potential mechanisms through which the application of a magnetic field may enhance adsorption. Specifically, we have added a focused discussion outlining key physicochemical processes, such as magnetothermal effects, improved mass or charge transfer, and spin-selective electron dynamics, that may contribute to the observed increase in adsorption efficiency. This section has been supported with up-to-date references from recent literature to provide a solid theoretical foundation for the proposed mechanisms.

 

3. Is it possible to perform in-situ magnetic field application of the adsorption/desorption process?

 

R: This is an excellent suggestion. Although our current experimental setup involved pre-treatment under a magnetic field, we agree that in-situ field application could provide more realistic insights into dynamic behavior. While we were not able to include in-situ data in this revision due to equipment limitations, we have discussed this as a future direction and acknowledged the importance of such studies in the manuscript. To address this importance, a complementary sentence was added into conclusion section.

 

 

4. Again, the following sentence does not say the mechanism or clear magnetic phenomena behind the process. And no reference for such phenomena. "in the presence of a magnetic field suggests that the application of the magnetic field may enhance the interaction between Ferroxite and Atrazine, possibly by promoting better dispersion of the adsorbent or altering the surface properties of Ferroxite, thereby increasing its efficiency in adsorbing Atrazine.

 

R: We acknowledge for this valuable observation. In fact, there is a lack of clarity and references in the original statement. In the revised version, we have revised the sentence and included references that support the idea that static magnetic fields can influence the dispersion and surface charge distribution of magnetic nanomaterials, leading to enhanced adsorption.

 

5. How do antiferromagnetic properties prevent? "antiferromagnetic 235 properties prevent the field from significantly altering its behavior, limiting the 236 enhancement of adsorption."

 

A: Thank you for your observation. We have clarified this point in the revised manuscript. The antiferromagnetic nature of Ferroxite implies that the magnetic moments are internally compensated, resulting in minimal net magnetization. This property reduces the impact of external magnetic fields on the material’s surface characteristics, thereby limiting the extent to which adsorption can be enhanced. The paragraph has been revised accordingly to better reflect this mechanism.

 

 

6. Where is the reference that the duration of the magnetic field could alter the adsorption/desorption properties?

 

A: We thank the reviewer for raising this important point. In the revised manuscript, we have incorporated a specific discussion addressing the influence of magnetic field exposure duration on adsorption/desorption properties. While the literature on this aspect is still emerging, recent studies have suggested that prolonged exposure to magnetic fields can lead to structural or surface modifications in magnetic materials, as well as enhanced charge or mass transport, which may, in turn, affect adsorption dynamics. We have included relevant references in the revised version to support this discussion and highlight the potential effects of magnetic field application on the adsorption process.

 

7. No magnetic studies have been done on the absorbent during any process.

 

A: We appreciate the reviewer’s comment. Although the present study does not include conventional magnetic characterizations such as hysteresis loops or magnetization measurements, the adopted experimental methodology directly assesses the influence of an external magnetic field on the material performance. The pronounced contrast in adsorption behavior between Ferroxite (a material responsive to magnetic fields) and Hematite (a non-responsive counterpart) provides clear functional evidence that the magnetic properties of Ferroxite play a significant role in the removal of atrazine. Therefore, within the scope of this study, the experimental results offer compelling support for the relevance of magnetic field effects, even in the absence of additional quantitative magnetic characterization.

 

8. The entire work does not have any relevent magnetic studies. A strong proof of magnetic experiments is required.

 

A: We appreciate the reviewer’s observation regarding the lack of conventional magnetic characterization. While we acknowledge that the current work does not include detailed magnetic measurements such as hysteresis curves or magnetization analysis, we respectfully emphasize that the study presents a novel yet preliminary investigation into the magnetic sensitization of Ferroxite in the presence of an applied magnetic field. This relevant result, which clearly demonstrates the material's enhanced adsorption performance under magnetic influence—contrasted with the non-responsive behavior of Hematite—constitutes an innovative contribution that may serve as a foundation for future, more comprehensive studies. The results presented in our paper highlight ferroxyhyte as an efficient, magnetically responsive, and low-cost material for the removal and degradation of atrazine. It is important to mention here that the efficient removal and degradation of atrazine is of great environmental significance, given that this herbicide is widely used and has been shown to exert numerous detrimental effects on the environment, particularly in relation to soil and water contamination [44]. In addition to being an effective material for the removal of this agrochemical, ferroxyhyte offers the advantages of being low-cost and easily obtainable, although still relatively little-known [40]. Beyond these previously mentioned benefits, δ-FeOOH possesses a greater number of surface -OH groups compared to magnetite and maghemite [45], which makes it an excellent candidate for interacting with specific molecules such as atrazine. Aditionally, we see this work as a starting point for subsequent investigations that could explore in greater depth the behavior of this system and elucidate the underlying mechanisms involved. Such studies would be well-positioned to incorporate advanced magnetic characterizations and systematically address the influence of various magnetic field parameters. Thus, within the defined scope and objectives of this study, we believe the current findings offer meaningful preliminary insight into the magnetic field–material interaction, even in the absence of full magnetic profiling. In the new version, we insert more discussion about all of these advantages mentioned here.

 

9. What are the possible magnetic techniques that could complement/support the manuscript?

 

A: We thank the reviewer for this helpful suggestion. We now include a discussion on relevant magnetic techniques that could strengthen future studies, such as Magnetic Force Microscopy (MFM), Mössbauer spectroscopy, and AC susceptibility measurements. These can elucidate fine-scale magnetic behavior, surface magnetic domain interactions, and dynamic magnetic responses.

 

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The comments are well addressed.