U(VI) adsorption in water by sodium alginate modified Bacillus megaterium

The surface of Bacillus megaterium was modified by coating sodium alginate. The modified B. megaterium before and after adsorption were characterized by SEM, FTIR and XPS. The effects of pH, reaction time, initial U(VI) concentration and adsorbent dosage on the adsorption of U(VI) by the modified B. megaterium were studied by batch adsorption experiments. The adsorption process was studied by pseudo-first-order kinetics and pseudo-second-order kinetic models, Langmuir and Freundlich isotherms. The results showed that the maximum adsorption capacity of U(VI) was 74.61 mg g−1 under the conditions of pH 5.0, adsorbent 0.2 g l−1, 30°C and initial U(VI) concentration of 15 mg l−1. The adsorption process accords with pseudo-first-order kinetics and Langmuir isotherm. The adsorption capacity of U(VI) by the modified B. megaterium was still higher than 80% after five times of desorption and reuse experiments. In conclusion, the sodium alginate modified B. megaterium was an ideal material for U(VI) biosorption.


1.
In summary, FTIR is mentioned twice. No details about SEM was given. 2.
In the Introduction part, last paragraph 3rd line it is mentioned as "little environmental harm". It can be refined. 3.
In the desorption process, adsorbent after getting reacted with Hcl, U (VI) is obtained as supernatant. How the U (VI) supernatant will be disposed of? It may require further treatment. It would be helpful if this question is answered? 4.
No proper discussion on results was given. 5.
For each and every parameter optimization, no proper justification was given for the values obtained such as effect of pH, effect of adsorbent dosage etc. 6.
The symbol for pH was not mentioned correctly. 7.
Freundlich spelling was wrong, it was mentioned as Friedlich 8.
In the fig 4 C, no clear explanation was given for the negative trend in the graph. 9.
Graphs should be very clear. The values are not legible.

Decision letter (RSOS-202098.R0)
This year has been very difficult for everyone, and we want to take the opportunity to thank you for your continued support in 2020.
The Royal Society Open Science editorial office will be closed from the evening of Friday 18 December 2020 until Monday 4 January 2021. We will not be responding during this time. If you have received a deadline within this time period, please contact us as soon as possible to allow us to extend the deadline. If you receive any automated messages during this time asking you to meet a deadline, we offer apologies and invite you to respond after the festive period or during normal working hours.
With our best for a peaceful festive period and New Year, and we look forward to working with you in 2021.
Dear Dr Li: Title: U(VI) adsorption in water by sodium alginate modified Bacillus megaterium Manuscript ID: RSOS-202098 Thank you for your submission to Royal Society Open Science. The chemistry content of Royal Society Open Science is published in collaboration with the Royal Society of Chemistry.
The editor assigned to your manuscript has now received comments from reviewers. We would like you to revise your paper in accordance with the referee and Subject Editor suggestions which can be found below (not including confidential reports to the Editor). Please note this decision does not guarantee eventual acceptance.
Please submit your revised paper before 15-Jan-2021. Please note that the revision deadline will expire at 00.00am on this date. If we do not hear from you within this time then it will be assumed that the paper has been withdrawn. In exceptional circumstances, extensions may be possible if agreed with the Editorial Office in advance. We do not allow multiple rounds of revision so we urge you to make every effort to fully address all of the comments at this stage. If deemed necessary by the Editors, your manuscript will be sent back to one or more of the original reviewers for assessment. If the original reviewers are not available we may invite new reviewers.
To revise your manuscript, log into http://mc.manuscriptcentral.com/rsos and enter your Author Centre, where you will find your manuscript title listed under "Manuscripts with Decisions." Under "Actions," click on "Create a Revision." Your manuscript number has been appended to denote a revision. Revise your manuscript and upload a new version through your Author Centre.
When submitting your revised manuscript, you must respond to the comments made by the referees and upload a file "Response to Referees" in "Section 6 -File Upload". Please use this to document how you have responded to the comments, and the adjustments you have made. In order to expedite the processing of the revised manuscript, please be as specific as possible in your response. ********************************************** RSC Associate Editor: Comments to the Author: (There are no comments.)

RSC Subject Editor:
Comments to the Author: (There are no comments.) ********************************************** Reviewers' Comments to Author: Reviewer: 1 Comments to the Author(s) In this manuscript, the authors modified Bacillus megaterium with sodium alginate, and characterized the material in detail. The sorption of U(VI) was studied under different experimental conditions and discussed the results in detail. The contents are important for the removal of U(VI) from aqueous solutions. After reading the manuscript, I think it can be accepted for publication after revision. Special comments: 1. The study is been done only using pure Uranium solution, but no real or simulated solution was used as a case study. The author should use real or simulated solution uranium waste water. 2. In actual waste solution what are the interfering metal ions present and what is the effect of those metal ions on adsorption should also be included. 3. Page 2 Line 56-59: Please correct the sentence, "In recent years, the research on remediation of uranium wastewater pollution has emerged in an endless stream. Mainly contain chemical precipitation, bioremediation (including phytoremediation and microbial remediation), adsorption, and so on[3]". Use of 'so on' should not be done here. Names of the important separation methods and their inferiority compared to adsorption with respect to specific application may be added here. 4. Page 3 Line 37: "Experimental materials" Use only "materials" instead of " Experimental materials". The grade/quality, brand/make/purchasing company of all the used chemicals must be mentioned. Authors can refer any paper given in references. 5. Page 4 Line 27: Use "ArsenazoIII spectroscopic method" 6. Page 4 Line 37-38: "respectively" should come after concentrations of U(VI). 7. " Figure

Recommendation?
Accept as is

Comments to the Author(s)
The authors revised the manuscript carefully and I recommend for publication.

Are the interpretations and conclusions justified by the results? Yes
Is the language acceptable? Yes

Do you have any ethical concerns with this paper? No
Have you any concerns about statistical analyses in this paper? No

Recommendation?
Accept as is

Comments to the Author(s)
Accepted.

Decision letter (RSOS-202098.R1)
The editorial office reopened on 4 January 2021. We are working hard to catch up after the festive break. If you need advice or an extension to a deadline, please do not hesitate to let us know --we will continue to be as flexible as possible to accommodate the changing COVID situation. We wish you a happy New Year, and hope 2021 proves to be a better year for everyone. Comments to the Author(s) The authors revised the manuscript carefully and I recommend for publication.
Reviewer: 2 Comments to the Author(s) Accepted. Response: The comments from the reviewers are very good. We have revised the original statement and added relevant contents. The sentence has been changed to " In recent years, the main remediation methods of uranium wastewater include chemical precipitation, biological remediation (including phytoremediation and microbial remediation), adsorption, and ion exchange. Currently, chemical precipitation method is a usually used method at present, but when the dosage of chemical reagent is excessive, it will cause secondary pollution [3]. Uranium bioremediation in groundwater by microorganism shows that once the electron donors are stopped in the injection well, the reduced U(IV) will be oxidized to U(VI)

Responses to editor and reviewers
quickly. It can not achieve the long-term remediation [4]. Phytoremediation is an effective method to treat uranium contamination in topsoil [5]. Adsorption method has the advantages of wide selection of adsorbents, high adsorption efficiency, high