High-Performance Hydrogel Based on Modified Chitosan for Removal of Heavy Metal Ions in Borehole: A Case Study from the Bahariya Oasis, Egypt

Round 1

Reviewer 1 Report

Authors have prepared sulfonated chitosan adsorbents to remove heavy metals especially the Fe(III) species from both synthetic and real contaminated waters. Manuscript has some interesting results. However, experimental results need to be explained elaborately. Manuscript is prepared carelessly and need to be completely revised for the language correction. Following comments need to be incorporated for the improvement of the manuscripts.

1.     Abstract need to be improved. Authors have not mentioned about the sulfonated chitosan used for the adsorption which is the key aspect of the study. Abstract need to be thoroughly checked for grammar correction and sentence formation.

2.     Introduction section need to be improved by incorporating the literatures of other adsorbents used to remove Fe(III) species, especially polymeric /biopolymeric materials. Also need to elaborate how this present study is different for others.

3.     Figure 1 can be added with EDS mapping to better the differentiation between the sulfonated and non-sulfonated polymer

4.     Authors need to clearly explain why adsorption need to be performed under UV and light.

5.     Clearly define what is the UV and light conditions used in the adsorption experiments such as wavelength, light source, and intensity.

6.     Explain why there is an enhancement in the adsorption performance with the presence of UV and light and detail the chemistry behind it, if possible, with the reaction equations.

7.     Compare the adsorption capacity of the as prepared polymers with others.

8.     It is recommended to change the order of Sections 2.3 and 2.4 in which the study area can be explained first, and the treatment of contaminated water need to be explained later.

9.     In section 2.3, why the selectivity was higher for removing Na, Ca, Mg than the other elements?

10.  Authors need to revise the complete manuscript for the language correction.

11.  Number of references are too high. Unnecessary references can be removed.

 

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

My opinion is that the proposed paper is interesting and deserves publication. However, I strongly recommend a thorough revision of the use of English. In addition to this aspect, I noticed that on line 53 the word "Dam" is missing. Eventually, I am a bit perplexed on the choice of "Catalysts" as journal for publication, "Sustainability" or "Water" being more obvious chioces.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The authors show an interesting work for the wastewater treatment and potabilization using an economical adsorbent material. Although the work is appropiate to publication, there are some issues to improve.

EDS analysis is not appropriate for the elemental characterization.

SEM images must be improved.

XRD analysis was not considered?

In conclusion the work can be published in Catalyst.

Author Response

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Author Response File: Author Response.pdf