Application of Functional Modification of Iron-Based Materials in Advanced Oxidation Processes (AOPs)

Round 1

Reviewer 1 Report

The manuscript "Application of functional modification of iron-based materials in advanced oxidation processes (AOPs)” had been reviewed. This review provides an summary of iron-based materials in AOPs. Authors collected important information about modified materials accelerate the electron transfer in AOPs, which is critical to the advance in this field.

Comments to improve the quality of this manuscript are listed below:

• Type of AOPs process should be listed and briefly described in the introduction.
• Although significant advancement has been made in the iron-based materials in AOPs over the past decade, there are still some challenges in this field that need to be overcome. In the end of manuscript the advantages and disadvantages should be listed and providing prospects for solving problems”Future development of iron-based materials in AOPs”
• I found the review about similar topics, they should be quoted in the introduction:

Application of iron-based materials in heterogeneous advanced oxidation processes for wastewater treatment: A review: Chemical Engineering Journal Volume 407, 1 March 2021, 127191.

Iron-based catalysts for persulfate-based advanced oxidation process: Microstructure, property and tailoring, Chemical Engineering Journal Volume 421, Part 2, 1 October 2021, 127845

Author Response

Responses to Comments from Reviewer #1

(1) Reviewer's comment: Type of AOPs process should be listed and briefly described in the introduction.

We sincerely thank you for the insightful comments. We have added Table 1 to list the types of AOPs processes (Line 62 in the updated manuscript) and a brief description of the types of AOPs processes used in wastewater treatment (Line 40- 45 in the updated manuscript).

The most widely used AOPs processes include photochemical degradation processes (UV/O₃, UV/H₂O₂), photocatalysis (TiO₂/UV, photo-Fenton reactive), and chemical oxidation processes (O₃, O₃/H₂O₂, H₂O₂/Fe²⁺) [1]. Meanwhile, alternative persulfate-AOPs utilizing peroxymonosulfate (PMS) or peroxydisulfate (PDS) instead of H₂O₂ have emerged and been researched in wastewater treatment [2].

(2) Reviewer's comment: Although significant advancement has been made in the iron-based materials in AOPs over the past decade, there are still some challenges in this field that need to be overcome. In the end of manuscript, the advantages and disadvantages should be listed and providing prospects for solving problems" Future development of iron-based materials in AOPs.

We entirely agree with your opinion that there are still some challenges in developing iron-based materials in AOPs. For example, the current iron-based composite materials are mainly processed in the laboratory, and there is still a lack of relevant research on their effectiveness in practical wastewater treatment. Moreover, developing a green and simple preparation method for iron-based materials is still a challenge in current research. Therefore, based on the advantages and disadvantages of iron-based materials in AOPs, we further put forward prospects for developing iron-based materials in AOPs. The updated manuscript shows the detailed contents on Line 391- 397.

(3) Reviewer's comment: I found the review about similar topics, they should be quoted in the introduction:

[1] Application of iron-based materials in heterogeneous advanced oxidation processes for wastewater treatment: A review: Chemical Engineering Journal Volume 407, 1 March 2021, 127191.

[2] Iron-based catalysts for persulfate-based advanced oxidation process: Microstructure, property and tailoring, Chemical Engineering Journal Volume 421, Part 2, 1 October 2021, 127845.

We included those two reviews in the introduction (Line 65 and 67 in the updated manuscript).

References:

1. Poyatos, J.M.; Muñio, M.M.; Almecija, M.C.; Torres, J.C.; Hontoria, E.; Osorio, F. Advanced Oxidation Processes for Wastewater Treatment: State of the Art. Water, Air, and Soil Pollution 2009, 205, 187-204, doi:10.1007/s11270-009-0065-1.
2. Lee, J.; von Gunten, U.; Kim, J.H. Persulfate-Based Advanced Oxidation: Critical Assessment of Opportunities and Roadblocks. Environ Sci Technol 2020, 54, 3064-3081, doi:10.1021/acs.est.9b07082.

Author Response File: Author Response.docx

Reviewer 2 Report

This is a very short review without having sufficient information to show the commercialization of the iron-based materials.

The literature is EXTREMELY short and without any information related to the current nanomaterials used for AOP. Besides, what are the key properties that make authors to say that iron-based materials could compete with the commercial products? All these information is missing.

Besides, this review lacks key figures related to morphology and properties of iron-based materials. When it comes to Table 1, the discussion is very simple. Authors should further discuss the efficiency of these materials in AOP in terms of % of pollutant removal/elimination.

Conclusion is very surface and does not provide insights towards commercialization of the iron-based materials.

Furthermore, authors should discuss the manufacturing cost of iron-based materials and its operating cost during AOP. Also, discuss how to manage these materials after AOP process.

The abstract is related to organic pollutants, but the review is very little related to the efficiency of iron-based materials in degrading specific pollutants. All these should be thoroughly reviewed.

Author Response

Responses to Comments from Reviewer #2

(1) Reviewer's comment: This is a very short review without having sufficient information to show the commercialization of the iron-based materials.

We appreciate your thoughtful comments. We further provided the information to introduce the commercialization of the iron-based materials, and the detailed contents were shown in a newly added Section 5 of the manuscript (Line 336-397 in the updated manuscript). For the description of the commercialization of iron-based materials in the updated manuscript, we mainly analyzed the feasibility and related challenges of the commercial application of iron-based materials in wastewater treatment from the aspects of the manufacturing methods, operating costs, and management of these materials in the laboratory. The detailed contents were as follows:

1) The detailed contents of the manufacturing methods of iron-based materials were shown on Line 366- 371 in the updated manuscript.

2) The detailed contents of the operating costs of iron-based materials were shown on Line 372- 381 in the updated manuscript.

3) The detailed contents of the management of iron-based materials were shown on Line 382- 390 in the updated manuscript.

(2) Reviewer's comment: The literature is extremely short and without any information related to the current nanomaterials used for AOP.

Nanomaterials have properties of high surface area and high catalytic activity, which have been increasingly employed in AOPs [1,2]. We have added the current nanomaterials used for AOPs (Line 46-51 in the updated manuscript).

(3) Reviewer's comment: Besides, what are the key properties that make authors to say that iron-based materials could compete with the commercial products? All these information is missing.

Iron-based materials have the characteristics of environmental friendliness, variety of morphologies, recyclability, and potential in photocatalysis, which enable iron-based materials to prioritize in AOPs compared with the other commercial products [3-5]. First of all, iron-based materials are more available to be obtained in the environment [6]. Secondly, the various morphologies of iron-based materials modified by different processes give iron-based materials a preferential advantage in catalytic efficiency over other materials [4,7]. Thirdly, iron-based materials as a magnetic materials could be easily removed from water by simply using a magnetic field gradient obtained with a magnet or electromagnet and recycled [5,8,9]. Finally, iron-based materials can extend the photocatalytic of TiO₂, which is widely used in wastewater treatment, from UV light irradiation to the visible light region [10,11]. Meanwhile, iron-based materials also have great photocatalytic potential in AOPs [3]. The detailed properties of iron-based materials were shown on Line 351-364 in the updated manuscript.

(4) Reviewer's comment: Besides, this review lacks key figures related to morphology and properties of iron-based materials.

The morphology, fundamental properties such as BET surface area, lattice size, and stability of iron-based materials can affect the catalytic performance of iron-based materials in AOPs [12-14]. We have added Table 3 listing the relevant morphologies and the key figures such as BET surface area, lattice size, and the number of cycles of common iron-based materials (Line 348, Line 349 in the updated manuscript). And a brief description of the changes in the morphology and properties of common iron-based materials were shown on Line 338-347 in the updated manuscript.

(5) Reviewer's comment: When it comes to Table 1, the discussion is very simple. Authors should further discuss the efficiency of these materials in AOP in terms of % of pollutant removal/elimination.

We have thoroughly modified Table1, which is Table 2 in the updated manuscript (Line 287, Line 295, and Line 316 in the updated manuscript). We have included more discussion about contaminant removal efficiency of these materials in AOPs in the updated manuscript (Line 288-295, Line 306-308, Line 311-313 in the updated manuscript).

(6) Reviewer's comment: Conclusion is very surface and does not provide insights towards commercialization of the iron-based materials.

We have added Section 5 to discuss the commercialization of the iron-based materials in the updated manuscript. We also put together a discussion about some challenges need to be overcome in the commercialization iron-based materials in AOPs (Line 416-424 in the updated manuscript).

 (7) Reviewer's comment: Furthermore, authors should discuss the manufacturing cost of iron-based materials and its operating cost during AOP. Also, discuss how to manage these materials after AOP process.

 We appreciate your thoughtful comments. For the currently collected literature on the application of iron-based materials in AOPs, researchers mainly focus on describing the manufacturing methods of iron-based materials in the laboratory. There is few relevant quantitative analysis of the manufacturing cost and operating cost of iron-based materials in AOPs. Therefore, we could only discuss the relevant factors affecting iron-based materials' manufacturing cost and operating cost in AOPs from a laboratory research perspective. Meanwhile, the management of iron-based materials in the laboratory is mainly through filtration, centrifugation, and magnetic sedimentation to separate from water (Line 366-390 in the updated manuscript). 

(8) Reviewer's comment: The abstract is related to organic pollutants, but the review is very little related to the efficiency of iron-based materials in degrading specific pollutants. All these should be thoroughly reviewed.

We appreciate the comment. Although the removal efficiency of iron-based materials for organic pollutants is not the primary discussion of this study, we included some discussion about the removal efficiency of iron-based materials for organic pollutants in the updated manuscript. Furthermore, we have rewritten the sentence on Line 13-15, 28-31 in the original manuscript. The detailed contents were shown as follows:

1) We have discussed the removal efficiency of these materials to degrade organic pollutants in AOPs, and the detailed contents were shown on Line 288-295, Line 306-308, and Line 311-313 in the updated manuscript).

2) We have deleted " for removing organic pollutions," and the modified sentence is " Advanced oxidation processes (AOPs) have become a favored approach in wastewater treatment due to the high efficiency and diverse catalyzed ways" (Line 13-14 in the updated manuscript).

3) We have deleted " to degrade the refractory organic pollutants," and the modified sentence is " Combining the advantages of different modified materials to develop iron-based materials with composite modification methods can enhance the catalytic performance of iron-based materials in AOPs for further application in wastewater treatment." (Line 28-31 in the updated manuscript).

References:

1. Cardoso, I.M.F.; Cardoso, R.M.F.; da Silva, J. Advanced Oxidation Processes Coupled with Nanomaterials for Water Treatment. Nanomaterials (Basel) 2021, 11, doi:10.3390/nano11082045.
2. Bethi, B.; Sonawane, S.H.; Bhanvase, B.A.; Gumfekar, S.P. Nanomaterials-based advanced oxidation processes for wastewater treatment: A review. Chemical Engineering and Processing - Process Intensification 2016, 109, 178-189, doi:10.1016/j.cep.2016.08.016.
3. Luo, H.; Zeng, Y.; He, D.; Pan, X. Application of iron-based materials in heterogeneous advanced oxidation processes for wastewater treatment: A review. Chemical Engineering Journal 2021, 407, doi:10.1016/j.cej.2020.127191.
4. Zhang, H.; Chen, S.; Zhang, H.; Fan, X.; Gao, C.; Yu, H.; Quan, X. Carbon nanotubes-incorporated MIL-88B-Fe as highly efficient Fenton-like catalyst for degradation of organic pollutants. Frontiers of Environmental Science & Engineering 2019, 13, doi:10.1007/s11783-019-1101-z.
5. Zhu, S.; Wang, W.; Xu, Y.; Zhu, Z.; Liu, Z.; Cui, F. Iron sludge-derived magnetic Fe-0/Fe3C catalyst for oxidation of ciprofloxacin via peroxymonosulfate activation. Chemical Engineering Journal 2019, 365, 99-110, doi:10.1016/j.cej.2019.02.011.
6. Ambashta, R.D.; Sillanpaa, M. Water purification using magnetic assistance: a review. J Hazard Mater 2010, 180, 38-49, doi:10.1016/j.jhazmat.2010.04.105.
7. Shukla, P.; Wang, S.; Sun, H.; Ang, H.-M.; Tade, M. Adsorption and heterogeneous advanced oxidation of phenolic contaminants using Fe loaded mesoporous SBA-15 and H2O2. Chemical Engineering Journal 2010, 164, 255-260, doi:10.1016/j.cej.2010.08.061.
8. Ferroudj, N.; Nzimoto, J.; Davidson, A.; Talbot, D.; Briot, E.; Dupuis, V.; Bee, A.; Medjram, M.S.; Abramson, S. Maghemite nanoparticles and maghemite/silica nanocomposite microspheres as magnetic Fenton catalysts for the removal of water pollutants. Applied Catalysis B-Environmental 2013, 136, 9-18, doi:10.1016/j.apcatb.2013.01.046.
9. Graham, L.J.; Atwater, J.E.; Jovanovic, G.N. Chlorophenol dehalogenation in a magnetically stabilized fluidized bed reactor. AIChE Journal 2006, 52, 1083-1093, doi:10.1002/aic.10681.
10. OHNO, T. Development of visible light sensitive TiO2 photocatalysts and their sensitization using Fe3+ ions. Journal of  the  Japan  Petroleum  Institute,  49,  (4),  168-176  (2006) 2006.
11. Jian Zhu, J.R., Yuning Huo, Zhenfeng Bian, and Hexing Li*. Nanocrystalline Fe/TiO2 Visible Photocatalyst with a Mesoporous Structure Prepared via a Nonhydrolytic Sol-Gel Route. J. Phys. Chem. C 2007, 111, 18965-18969 2007.
12. Liu, D.; Wang, C.; Song, Y.; Wei, Y.; He, L.; Lan, B.; He, X.; Wang, J. Effective mineralization of quinoline and bio-treated coking wastewater by catalytic ozonation using CuFe2O4/Sepiolite catalyst: Efficiency and mechanism. Chemosphere 2019, 227, 647-656, doi:10.1016/j.chemosphere.2019.04.040.
13. Lyu, C.; He, D.; Mou, Z.; Yang, X. Synergetic activation of peroxymonosulfate by MnO2-loaded beta-FeOOH catalyst for enhanced degradation of organic pollutant in water. Sci Total Environ 2019, 693, 133589, doi:10.1016/j.scitotenv.2019.133589.
14. Wang, M.; Fang, G.; Liu, P.; Zhou, D.; Ma, C.; Zhang, D.; Zhan, J. Fe 3 O 4 @β-CD nanocomposite as heterogeneous Fenton-like catalyst for enhanced degradation of 4-chlorophenol (4-CP). Applied Catalysis B: Environmental 2016, 188, 113-122, doi:10.1016/j.apcatb.2016.01.071.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Accept in present form

Reviewer 2 Report

Authors have responded my comments professionally.

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

Based on the literature in the database, the author systematically analyzed the widely used iron base materials and main modified cations in environmental remediation. The effect of modification of iron based materials on AOPs performance was analyzed and the mechanism related to the change of pollutant removal efficiency was studied. The manuscript is correct in theory and experiment. I require that some appropriate modifications be made prior to this to be suitable for publication in Sustainability.

1. Please keep the format of each paragraph consistent. For example, the format of the paragraph in Figure 1 below is inconsistent with other paragraphs or the punctuation in the paragraph of the following formula (5) needs to be unified.
2. All formulas should have consistent formatting, including corner marks and fonts. All formulas should have a consistent format, including corner marks and fonts. For example, formula (4) is inconsistent with formula (2).
3. Please pay attention to the uniform format and corner labels, for example, Fe (II) and Fe²⁺, Fe (III) and Fe³⁺ can be expressed in a unified way.
4. The quality of pictures needs to be improved and all pictures need to be cited, please list the source in detail! For example, the text in Figure A1 is not clear enough.
5. Please keep the table format consistent, for example, the last line in Table 2 is inconsistent with other lines.
6. It is suggested that the author quote no more than three references in the sentence, such as [46, 52–54]、[55–58].
7. Please keep the formula content consistent with the paper, such as, OH^. in formula (10).

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

The Title:

Application of functional modification of iron-based materials in advanced oxidation processes (AOPs)

There are many important factual errors at the academic level at work.The work is not refined, so that it can be published even after submitting comments from the reviewer.

I recommended REJECT the publication

• Line 34- check the ions: SO42- or HSO4-
• Write in an abstract what has been done as a result of the research, it is currently not clear and clear
• Line 75- there isn’t Table S1
• Fig. 1- What period does the analysis?
• Fig. 2 was based on the authors' own research?
• the inscriptions in Fig. 2 are invisible
• Line 123- where are the Figure S1, S1a, S1c?
• Line 186- explain the SO5- ion notation, is it a combination in a complex?   
• Line 191- -077 V
• line 198- check the reaction: 4-OH (?)
• line 203- there isn’t the Figure S2
• Reactions are written in different fonts, they are not agreed - the law of conservation of mass is not respected
• Line 239 errors in the recording of the reaction
• Table 2 - unreadable reactions