The Effect of Gamma Irradiation on the Ion Exchange Properties of Caesium-Selective Ammonium Phosphomolybdate-Polyacrylonitrile (AMP-PAN) Composites under Spent Fuel Recycling Conditions

Round  1

Reviewer 1 Report

The manuscript describes the synthesis and use of AMP-PAN as an ion exchange sorbent selective for Cs metal ions and the effect of gamma radiation on the sorbent performance.  The manuscript is of interest and well written.  However before I can recommend publication, the following points need to be addressed:-

The authors have not demonstrated whether the AMP-PAN composite was successfully synthesized with the required pore sizes.

The authors should include details and results in regards to the characterisation of the AMP- PAN composite using FT-IR, SEM, BET microscopy etc...  This should be considered a basic requirement whenever a synthesis step has been carried out especially where the method has been adapted. 

Line 75 The mixture was then sprayed into a large excess of deionised water through a confined jet nebuliser to form 2-3 mm sized, spherical, porous beads of AMP76 PAN.  How uniform was the size of the beads?  The authors should calculate PDI for their beads. How big were the pore sizes?  Again the authors should determine this and include it into the manuscript.

Figure 2:  The legend should be labelled with the units for clarity to the reader.

Figure 3:  How many times was the assay performed?  Error bars should be added to the figure.

How does the binding capacity compare against other metal ions present?  The authors should demonstrate that the absorbant is selective for Cs ions as claimed in the title.   

Author Response

BET and SEM data inserted, clarified pore size as per previous work.

Particle size distribution measurement is not possible with this material.

Figure 2 caption amended to clarify.

Experimental error now stated in experimental section.

Clarified selectivity of composites with reference to prior work by ourselves and others.

Reviewer 2 Report

I would suggest slight analyses of the results from Gelis V.M., Kharitonov OV, Firsova L.A., Milyutin V.V., Semenova T.A., Logunov M.V. Sorption extraction of cesium-137 on ammonium phosphomolybdate from technological products in the preparation of high-level samples for elemental analysis. / Issues of radiation safety (Voprosy radiatsionnnoi bezopasnosty, PO. Mayak Edition), 2009, № 1, p. 3-11 (in Russ.) in the introduction together with ref. 7-13.

Author Response

Reference inserted as requested.

Round  2

Reviewer 1 Report

I feel that the authors have addressed some points, but I´m not convinced that the composite material has been properly characterised.  For instance, the authors are citing their previous work even though the article is still in press and cannot be properly accessed.  I can only assume that the authors did a comprehensive characterisation in their previous work.   Are the authors salami slicing their research in this instance?  I would like to see the characterisation of the chemical composition using EDS, FTIR or XPS.  This would make for a more compelling and convincing argument to support their claim that they have made a PAN-AMP composite. 

Author Response

The second revised document now complies with the majority of the reviewers requests.

The paper has been spell and grammar checked.

Our previous paper 'Removal of Caesium from simulated spent nuclear fuel  dissolver liquor' J Chromatogr Sep Tech, vol 10, 417, 2019 has now been published.

We have included additional information to substantiate the structure of AMP PAN.

Unfortunately we do not have access to XPS.

Author Response File: Author Response.pdf

Round  3

Reviewer 1 Report

The authors have addressed most of the points.