Influences and Isotherm Models on Phosphorus Removal from Wastewater by Using Fe3+-Type UBK10 Cation Exchange Resin as Absorbent
Round 1
Reviewer 1 Report
In this study, authors aimed to investigated the potential of a cation exchange resin that adsorbs ferric ions (Fe3+ type) for the removal of P. There are some problems for the author to address.
1. In line 52 and 53, there are some different approaches to remove P, what are the advantages of using this method compared to other methods in this article? Please provide a comparison of this paper with other literature.
2. Line 59, the author mentioned the use of anion exchange resin for adsorption of P, then what are the differences between cation exchange resin adsorption and it? What are the advantages of each other?
3. Line 73, you mentioned the adsorption of Se by Fe resin. Therefore, compared with the adsorption of P and Se, is their adsorption mechanism and process the same? Is there a difference between the two adsorption processes?
4. In Section 3.1, why does the adsorption amount decrease with the increase of the dosage? How is the adsorption calculated? Please explain the problem.
5. What is the adsorption mechanism? Is it related to electric charge? I think you can further prove the mechanism by using Zeta potential test.
6. Does the author consider the recycling performance of resin? Because recycling performance is a very important factor in practical application. So I think you should investigate the recycling performance of adsorbent.
7. After the resin absorbed the pollutant, Did the author post-treat the contaminant? What do you do with the absorbed P?
8. Will the adsorbed P desorb from the resin? How is it desorbed? Please explain the phenomenon.
9. There are some mistakes in grammar and tense. English writing can be further improved.
There are some mistakes in grammar and tense. English writing can be further improved.
Author Response
Thank you for your kindness.
We answer here the questions and suggestions from reviewer#1 against our manuscript. Also we would like to appreciate for your useful comments.
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
I carefully review this manuscript. Although I think the adsorption of phosphorous on modified UBK10 samples, this manuscript is still completed.
Line 8-12: These sentences should be modified and changed. The content is not appropriate in Abstract section. The authors are required to describe important results and related discussion obtained by experiments.
Line 13: “the column’s superior adsorption ability” is changed to “a superior adsorption ability of the column”.
As a whole, the content on experimental results is weak in Abstract.
Introduction
Line 23: The description of “P” is unexpected. “Phosphorus” is better.
Line 32: “depletion[2]” is changed to “depletion [2]”.
Line 34: There are an unnecessary space between mg/L and [4].
Line 36: The use of possessive should be avoided. “plants’”
Line 39: “reduced[5]” is changed to “reduced [5]”.
Line 53: [10,11,12] is changed to [10-12].
Materials and methods
Line 88: “meq/cm3” is changed to “meq/cm3”.
Line 88: How was the UBK 10 sample washed before using?
Line 88: Don’t start the sentence with “10%”.
Line 89: “cm3” is changed to “meq/cm3”.
Line 91: Can the author(s) show the instrumental evidence or results on the fact that the UBK 10 sample has ferric ions?
Line 106: There are two periods.
Line 119-124: Was this method used for determining the phosphorous content in the solution? If so, more description and explanation is required.
Line 126-128: The volume of the solutions is unclear.
Line 129: Don’t start the sentence with “200 rpm”
Line 130: The wavelength used is unclear. In addition, molar absorption coefficient (e) is required.
Line 145: The use of possessive should be avoided. “surface’s”
Line 145: “surface[26]” is changed to “surface [26]”.
Line 151: “Eq.3” is changed to “Eq. 3”.
Line 153, 171: “Where” is changed to “where”.
Line 131, 153, 154: The expression of unit is mixed (mg/L-1 and mg/L), so it should be unified.
Line 158: “Eq.4” is changed to “Eq. 4”.
Line 162, 166, 169,190: A space is added between a word and reference number.
Line 168: “Eq5” is changed to “Eq. 5”.
Line 180: “Eq.7” is changed to “Eq. 7”.
Line 182: “Eq.8” is changed to “Eq. 8”.
Results and discussion
Line 193-207: The font is different from the other sections.
Figure 1: I think a straight line is obtained between the sample content (amount) and adsorbed amount. However, in this figure, data are scattered. The removal of phosphorous should be estimated or discussed from the adsorbed amount (mmol/g).
Before showing the results obtained from Figure 1, the results on pH dependence should be shown.
Figure 2: As far as I can see Figure 2, the adsorption of phosphorous on UBK 10 sample doesn’t reach the equilibrium. In this case, one can’t analyze the results with the isotherms.
Figure 3: The plots in this figure are too small. It is difficult to distinguish them.
What is the reason the adsorption of phosphorous increased with an increase in the NaCl concentration? More explanations are required. Can the authors show the mechanism?
What is the content of ferric ions for the used UBK 10 sample?
Can the author(s) prepare UBK 10 samples with different contents of ferric ions? The adsorbed amount strongly depends on the content of ferric ions.
Since the equilibrium is not reached from Figure 2, data can’t be analyzed using isotherm models.
I can understand the content of this manuscript. Howecver, the structure of content should be revised and modified.
Author Response
Thank you for your kindness.
We answer here the questions and suggestions from reviewer#2 against our manuscript. Also we would like to appreciate for your useful comments.
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors present the paper showing the adsorption of phosphate ions on Fe type UBK-10 cation exchange resin. As the name implies, these resins are not designed to adsorb phosphates, however, the experimental data of the authors show their effectiveness in adsorbing these anions.
Consideration of several equations describing the general adsorption isotherms indicates the occurrence of monolayer adsorption of phosphates.
The paper is written at a good scientific level. From the point of view of the reviewer, it is necessary to give a brief description of the ion exchange resin. The influence of other factors and substances could be monitored not only in terms of kinetics, but also in terms of changes in the maximum adsorption and Langmuir constant.
Author Response
Thank you for your kindness.
We answer here the questions and suggestions from reviewer#3 against our manuscript. Also we would like to appreciate for your useful comments.
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Authors have answered all my questions and revised the manuscript. I think it can be accepted for publication.
Minor editing of English language required
Author Response
Dear Reviewer 1
Thank you for your wonderful suggestion
Best regards,
Onchanok Juntarasakul
Reviewer 2 Report
The authors revised the manuscript.
Before publication, the RL value should be discussed, because it is shown in Table 1. Figure 6 shows the result of the analytical results of three isotherms.
The time course of adsorption at different doses is shown in Figure 2. However, which data were used for analysis by isotherms? It is unclear. In additon, the equilibrium is not obtained from Figure 2. The authors should dissolve this problem.
This manuscript has the quality of English for publication, although it is not sufficient.
Author Response
Dear Reviewer 2
Thank you so much for your wonderful comments
Please see the attachment.
Author Response File: Author Response.pdf
