Efficient Removal Of U(VI) Ions from Aqueous Solutions by Tannic Acid/Graphene Oxide Composites

Round 1

Reviewer 1 Report

The reviewed study entitled” Efficient removal of U(VI) ions from aqueous solutions by tannic acid/graphene oxide composites” concerns important issues.  

Introduction:

Why U (VI) was chosen to research?

Line 35-36: The lack of all materials used to sorption of radionuclide, e.g. synthetic zeolites.

Results:

Line 205-214: The lack comparison of this composites to another materials, which are described in the literature.

Line 229-233: The lack proposition of utilizations of worn out composites.

References:

In my opinion, it is advisable not to cite references before 2010 year due to their distant year of publication.

Author Response

Responses to Reviewer 1:

The reviewed study entitled” Efficient removal of U(VI) ions from aqueous solutions by tannic acid/graphene oxide composites” concerns important issues.  

Introduction:

1. Why U (VI) was chosen to research?

Response: Thanks for your suggestions. Uranium, a representative actinide element of radionuclides with a number of relatively radioactive products, has attracted great

concerns due to its extensive distribution, long half-life and carcinogenicity [1,2]. Uranium exposure will damage biological functions of kidney, brain, liver and other systems. Given environmental safety and public health, it is necessary to eliminate

trace level concentrations of U(VI) ions from contaminated aqueous solutions [3].

1. Line 35-36: The lack of all materials used to sorption of radionuclide, e.g. synthetic zeolites.

Response: Thanks for your suggestions. According to your suggestions, we have added other adsorbents in the article. Synthetic zeolites are a type of clay mineral, so synthetic zeolites have not been added in this paper.

Results:

1. Line 205-214: The lack comparison of this composites to another materials, which are described in the literature.

Response: Thanks for your suggestions. According to your suggestions, we have added other adsorbents in Table 4. In this experiment, the maximum adsorption capacity of TA/GO is 266.56 mg g^-1 under PH=5.0 and T=298K conditions, therefore, TA/GO composites has good adsorption performance for uranium ions.

Table 4. Comparison of U(VI) sorption capacity of TA/GO composites with other sorbents

1. Line 229-233: The lack proposition of utilizations of worn out composites.

Response: Thanks for your suggestions. Since in the multiple adsorption/desorption cycles experiment, each experiment requires a solid-liquid separation operation, there is a total loss of about 5 mg of adsorbent over the five cycles.

References:

1. In my opinion, it is advisable not to cite references before 2010 year due to their distant year of publication.

Response: Thanks for your suggestions. According to your suggestions, We have replaced some of the references, however, some of the references could not be removed.

Reference

[1] E. L. Shock, D. C. Sassani and H. Betz, Geochim. Cosmochim. Acta, 1997, 61, 4245–4266.

[2] Y. B. Sun, D. D. Shao, C. L. Chen, S. B. Yang and X. K. Wang, Environ. Sci. Technol., 2013, 47, 9904–9910.

[3] R. Hu, D. Shao, X. Wang. Graphene oxide/polypyrrole composites for highly selective enrichment of U(VI) from aqueous solutions. Polym. Chem 2014, 5.

[4] A. Mellah, S. Chegrouche, M. Barkat. The removal of uranium(VI) from aqueous solutions onto activated carbon: Kinetic and thermodynamic investigations, J Colloid Interface Sci 2006, 296, 434-441.

[5] G. Hao, T. Wen, X. Yang, S. Yang, J. Liao, J. Hu, D. Shao, X. Wang. Preconcentration of U(vi) ions on

few-layered graphene oxide nanosheets from aqueous solutions, Dalton Transactions 2012, 41, 6182-6188.

[6] Y. Sun, D. Shao, C. Chen, S. Yang, X. Wang. Highly efficient enrichment of radionuclides on graphene

oxide-supported polyaniline. Environ Sci Technol 2013, 47, 9904-10.

Special thanks to you for your good comments!

Author Response File: Author Response.docx

Reviewer 2 Report

This manuscript could be accepted for publication after a minor revision.

The authors have to use mL as measurement unit for volume not ml.

Check at page 4, line 105. Without (.

I recommend to compare the obtained results with the sorption capacity of other sorbents from the literature in order  to evidence the advantage of these new sorbents.

Author Response

Responses to reviewer 2

This manuscript could be accepted for publication after a minor revision.

1. The authors have to use mL as measurement unit for volume not ml.

Response: Thanks for your help. We feel really sorry for our carelessness, and we have corrected the “ml” into “mL”.

1. Check at page 4, line 105. Without (.

Response: Thanks for your help. We feel really sorry for our carelessness, and we have deleted “(”.

1. I recommend to compare the obtained results with the sorption capacity of other sorbents from the literature in order to evidence the advantage of these new sorbents.

Response: Thanks for your suggestions. According to your suggestions, we have added other adsorbents in Table 4. In this experiment, the maximum adsorption capacity of TA/GO is 266.56 mg g^-1 under PH=5.0 and T=298K conditions, therefore, TA/GO composites has good adsorption performance for uranium ions.

Table 4. Comparison of U(VI) sorption capacity of TA/GO composites with other sorbents

Reference

[1] A. Mellah, S. Chegrouche, M. Barkat. The removal of uranium(VI) from aqueous solutions onto activated carbon: Kinetic and thermodynamic investigations, J Colloid Interface Sci 2006, 296, 434-441.

[2] R. Hu, D. Shao, X. Wang. Graphene oxide/polypyrrole composites for highly selective enrichment of U(VI) from aqueous solutions. Polym. Chem 2014, 5.

[3] G. Hao, T. Wen, X. Yang, S. Yang, J. Liao, J. Hu, D. Shao, X. Wang. Preconcentration of U(vi) ions on

few-layered graphene oxide nanosheets from aqueous solutions, Dalton Transactions 2012, 41, 6182-6188.

[4] Y. Sun, D. Shao, C. Chen, S. Yang, X. Wang. Highly efficient enrichment of radionuclides on graphene

oxide-supported polyaniline. Environ Sci Technol 2013, 47, 9904-10.

Special thanks to you for your good comments!

Author Response File: Author Response.docx

Reviewer 3 Report

The authors of the article undertook the task of checking and assessing the effectiveness of removing U (VI) ions from aqueous solutions using tannic acid/graphene oxide composites. This topic is important from the point of view of environmental engineering, due to the fact that the results of the conducted research can be used to improve the current methods of wastewater treatment. Nevertheless, the authors did not avoid some mistakes, the list of which is provided below.

1. The introduction is very short compared to the number of citations; one sentence is e.g. described by several citations (lines 25, 38, 43 etc.) and the reference to these texts is not entirely clear. In addition, individual issues are described very briefly. The introduction also does not show why the authors undertook such research and what is innovative about it. For me as a reader, it is also not entirely clear what the novelty of this research is.
   
2. Figure 1 - the photo scale is completely unreadable.
3. Figure 3 - the size of this figure could be larger because nowadays the descriptions (e.g. of the axis) are poorly visible.
4. Equations (1-6) are completely blurry and unreadable. The authors did not check their manuscript before uploading the file to the system.
5. Figures 4 and 7 - the charts pasted inside these figures are too small (unreadable).
6. Overall, the editing of this manuscript is very poor, it looks sloppy, e.g. some figures are very large, others very small and difficult to read.
7. There are no spaces in the entire text before citations (e.g. line 25: "...human health[1-3].")
   
8. The summary is very weak - the manuscript contains some research results, and the summary is just 6 sentences from which nothing really comes out. Most of the sentences concern what has been done, not what the results of these analyzes are and what conclusions are drawn from them.

Author Response

Responses to Reviewer 3

The authors of the article undertook the task of checking and assessing the effectiveness of removing U (VI) ions from aqueous solutions using tannic acid/graphene oxide composites. This topic is important from the point of view of environmental engineering, due to the fact that the results of the conducted research can be used to improve the current methods of wastewater treatment. Nevertheless, the authors did not avoid some mistakes, the list of which is provided below.

The introduction is very short compared to the number of citations; one sentence is e.g. described by several citations (lines 25, 38, 43 etc.) and the reference to these texts is not entirely clear. In addition, individual issues are described very briefly. The introduction also does not show why the authors undertook such research and what is innovative about it. For me as a reader, it is also not entirely clear what the novelty of this research is.

Response: Thanks for your suggestions. According to your suggestions, we have made changes to the introduction. “In the present study, by combining the high specific surface area of graphene oxide and the high-level of active sites of tannic acid, tannic acid/graphene oxide composites as high selectivity and good recyclability adsorbents were prepared to increase the adsorption capacity of graphene oxide on radionuclides from wastewater at low pH, providing a certain basis for the safe treatment and disposal of radioactive wastewater.” has been used into the paper.

Figure 1 - the photo scale is completely unreadable.

Response: Thanks for your help. We feel really sorry for our carelessness, we have corrected the figure 1.

Figure 3 - the size of this figure could be larger because nowadays the descriptions (e.g. of the axis) are poorly visible.

Response: Thanks for your help, we feel really sorry for our carelessness. The figure 3 is poorly visible due to compression when inserting images. we have corrected the figure 3.

Equations (1-6) are completely blurry and unreadable. The authors did not check their manuscript before uploading the file to the system.

Response: Thanks for your help. We feel really sorry for our carelessness, we have corrected the equations (1-6).

Figures 4 and 7 - the charts pasted inside these figures are too small (unreadable).

Overall, the editing of this manuscript is very poor, it looks sloppy, e.g. some figures are very large, others very small and difficult to read.

Response: Thanks for your help. We feel really sorry for our carelessness, we have corrected the figure 4 and 7.

There are no spaces in the entire text before citations (e.g. line 25: "...human health[1-3].")

Response: Thanks for your help. We feel really sorry for our carelessness, we have corrected.

The summary is very weak - the manuscript contains some research results, and the summary is just 6 sentences from which nothing really comes out. Most of the sentences concern what has been done, not what the results of these analyzes are and what conclusions are drawn from them.

Response: Thanks for your help. We feel really sorry for our carelessness, we have corrected. “TA/GO composites were successfully synthesized, and their adsorption behavior toward U(VI) ions was studied by bath sorption experiments. The resultant TA/GO composites had excellent adsorption capacity in concentrating or removing U(VI) ions from aqueous solutions at low pH. The adsorption of U(VI) ions on TA/GO was controlled by contact time, pH, ionic strength, and the solid-liquid ratio. In addition, the adsorption of U(VI) ions on TA/GO followed pseudo-second-order kinetics and the Langmuir model. Moreover, TA/GO composites have outstanding selectivity for uranium ions in aqueous solutions containing other ions (Cs+, Sr2+, Co2+) and good recyclability for uranium adsorption. Therefore, TA/GO as high selectivity, excellent adsorption and good recyclability adsorbents is an ideal material to remove highly toxic U(VI) ions from wastewater.” has been used into the paper.

Special thanks to you for your good comments!

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

The authors took into account most of the comments from the review and largely improved the article as suggested. In my opinion, the article can be published.

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.