A Review of Research Progress in the Preparation and Application of Ferrate(VI)

Round 1

Reviewer 1 Report

Paper entitled “A review of research progress in the preparation and application of ferrate(VI)” meets the necessary standards for publication in this journal.

 

Please check the entire manuscript carefully for possible typographical errors. For example, in Table 3 "disadvantages" is written with a small letter. Table 5 is not very clear. At which pH and for which pollutant a certain combined technology is applied. I recommend his reconsideration.  Attention when writing references. They are not unitary.

Author Response

Point 1. For example, in Table 3 "disadvantages" is written with a small letter.

 

Response 1: Thanks for the suggestion, I've changed "d" to "D".

 

Point 2. Table 5 is not very clear. At which pH and for which pollutant a certain combined technology is applied.

 

Response 2: I readjusted the table and it looks clearer than before. You can also know under what conditions a certain hyphenated techniques is applied.Thank you very much for your advice to me.

Author Response File: Author Response.docx

Reviewer 2 Report

This paper introduced the properties and preparation methods of ferrate (VI). The application of ferrate (VI) for water treatment was summarized, and the hyphenated techniques of ferrate (VI) based on some defects was also discussed. In general, this review is interesting and meaningful for the application of ferrate (VI) for water treatment. I recommend its publication after minor revisions.

 1. In line 159, this paper pointed out that Na₂FeO₄ was obtained by the reaction of Na₂O₂ and Fe₂O₃ at 370 ℃, and thus the reaction conditions should be reflected in the chemical equation.

2. In line 220, “The concentration an important role in the production of ferrate (VI)” refers to a wide range of concentrations without specific description. In the following article, the influence of lye concentration on the preparation of ferrate (VI) was mentioned, so it may be known that the above concentration means lye concentration. However, it is necessary to give readers a clear logic and make up for the missing content.

3. In line 226, the reason for the increase in the viscosity of the electrolyte is not mentioned.

4. In line 305. “It has been found that ferrate(VI) is an effective treatment method for phenolic compounds, and it can effectively degrade them quickly.” Ferrate is an oxidant rather than a method. This definition is wrong.

 Minor comments

1. The last sentence in the abstract needs to be completed, and the correct sentence is “In this review, three hyphenated techniques of ferrate(VI) are summarized”.

2. In 500 lines and 502, the equation and picture must be written consistently.

3. In Table 1, the chemical equation should be consistent on both sides.

4. There are some grammar mistakes in the whole manuscript. Please improve the writing.

Author Response

Point 1. In line 159, this paper pointed out that Na₂FeO₄ was obtained by the reaction of Na₂O₂ and Fe₂O₃ at 370 ℃, and thus the reaction conditions should be reflected in the chemical equation.

 

Response 1: Thanks for the suggestion. I have made changes to the specified equation.

 

 

Point 2. In line 220, “The concentration an important role in the production of ferrate (VI)” refers to a wide range of concentrations without specific description. In the following article, the influence of lye concentration on the preparation of ferrate (VI) was mentioned, so it may be known that the above concentration means lye concentration. However, it is necessary to give readers a clear logic and make up for the missing content.

 

Response 2: Thanks for the suggestion, I've added the exact content of this section.

The concentration of lye is also very important for the production of ferrate(Ⅵ)

 

Point 3. In line 226, the reason for the increase in the viscosity of the electrolyte is not mentioned.

 

Response 3: I've completed the reason, thank you again for your guidance.

Although the higher concentration of lye concentration can increase the concentration of ferrate(VI), at the same time, the increase of lye concentration will increase the viscosity of the electrolyte, causing the electrons to overcome the resistance of the electrolyte, which increase energy consumption, reduce the transfer efficiency, and inhibit the formation of ferrate(Ⅵ), thereby increasing the preparation cost.

 

Point 4. In line 305. “It has been found that ferrate(VI) is an effective treatment method for phenolic compounds, and it can effectively degrade them quickly.” Ferrate is an oxidant rather than a method. This definition is wrong.

 

Response 4: I have revised this sentence, thank you for correcting it.

Ferrate(VI) has a good removal effect on phenolic compounds and can effectively degrade phenolic compounds in a short time.

 

 Minor comments

Point 1. The last sentence in the abstract needs to be completed, and the correct sentence is “In this review, three hyphenated techniques of ferrate (VI) are summarized”.

 

Response 1: Thanks for the suggestion, I've revised this.

In this review, three hyphenated techniques of ferrate(VI) are summarized : ferrate(VI)-photocatalytic synergistic coupling, ferrate(VI)-PAA synergistic coupling and ferrate(VI)-PMS synergistic coupling.

 

Point 2. In 500 lines and 502, the equation and picture must be written consistently.

 

Response 2: Thanks for the reminder, I have unified the writing of equation and figure in review.

It was found that ferrate(VI) can act as an electron acceptor in the UV/TiO₂ system, and the decomposition of ferrate(VI) to Fe(IV), Fe(V), and Fe(III), shown in equation. 11-13, is accelerated under UV irradiation and accompanied by the generation of superoxide radicals [118], as shown in figure. 5.

 

Point 3. In Table 1, the chemical equation should be consistent on both sides.

 

Response 3: Thanks for the suggestion, I have made changes to Table 1.

Oxidants/Disinfectants	Reaction type	E0/V
Cl2		1.358
ClO2		0.854
O3		2.076
KMnO4		1.679
		1.507
Ferrate(Ⅵ)		2.20
		0.76

 

Point 4. There are some grammar mistakes in the whole manuscript. Please improve the writing.

 

Response 4: Thanks for the reminder, I identified and corrected grammatical errors that appeared in the paper.

1. In the review, the writing of the same word needs to be consistent, and the keywords"hyphenated techniques" is inconsistent with the previous one and needs to be changed.
2. In lines 45, 99 and 311, In lines 45, 99 and 311, the issue of letters being capitalized requires attention, which I corrected.
3. On line 389, before that, the ferrate (VI) in the paper is in the form of ferrate (VI), which needs to be consistent, and here it is written in Fe(VI), so modify this
4. In the line 445. The acronym NOM should be defined at its first use, because it may not be clear to all readers. Similarly, in line 586, the acronym DCF should be defined at its first use.So, I modified this.
5. The quotation marks in line 561 need to removed, only the back is seen, the front is not seen.

Author Response File: Author Response.docx