A Route to Selective Arsenate Adsorption in Phosphate Solutions via Ternary Metal Biopolymer Composites

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript aims to emphasize  the study of the adsorption properties of arsenate and orthophosphate in mixed systems onto the prepared TMCs. I believe that the manuscript can be published after the following revision:

1.       It is suggested that authors should abridge and present key elements of the abstract section to present a more explicit and clearer idea of the innovation.

2.       It is recommended that the authors supplement the vertical coordinate portion of the infrared spectrum in Figure 1.

3.       Due to the limitations of the SEM-EDS images, it is recommended that the authors supplement the original SEM images to facilitate the observation of the distribution of the surface morphology of the material.

4.       With the different distributions of elemental Fe shown in Figure 4, explain why there are different levels of iron oxide at different locations in the same sample.

5.       It is suggested that the authors explain the possible reasons for the differences in selectivity of different TMCs.

6.       Make sure all abbreviations are written out in full the first time used.

7.       The tiny typos and grammar errors should be corrected through the whole manuscript.

Comments on the Quality of English Language

Minor editing of English language required.

Author Response

Author Response to Reviewer Comments on MS ID: applsci-3163587

entitled “A route to selective arsenate adsorption in phosphate solutions via ternary metal biopolymer composites”

 

Reviewer #1

 

This manuscript aims to emphasize  the study of the adsorption properties of arsenate and orthophosphate in mixed systems onto the prepared TMCs. I believe that the manuscript can be published after the following revision:

1. It is suggested that authors should abridge and present key elements of the abstract section to present a more explicit and clearer idea of the innovation.

Response:

The authors have rephrased and modified the abstract to highlight the arsenate selectivity in presence of orthophosphate to address the reviewer comments.

 

 

2. It is recommended that the authors supplement the vertical coordinate portion of the infrared spectrum in Figure 1.

Response:

The authors improved the figures and added Y-Axes (“Intensity (a.u.)” for Figure 1 and Figure 6.

3. Due to the limitations of the SEM-EDS images, it is recommended that the authors supplement the original SEM images to facilitate the observation of the distribution of the surface morphology of the material.

Response: The authors included the originally obtained images for SEM-EDX imaging without surface mapping to facilitate inferences. Additionally, BET surface area was determined to complement the interpretation of the morphology by providing surface area measurements.

4. With the different distributions of elemental Fe shown in Figure 4, explain why there are different levels of iron oxide at different locations in the same sample.

Response:

A revised and updated discussion related to the reviewer query for Fig. 4 was provided in Section 3.1.

 

5. It is suggested that the authors explain the possible reasons for the differences in selectivity of different TMCs.

Response:

The authors provided citations to explain the adsorption mechanism (mainly inner sphere coordination with the metal centers, electrostatic interactions with the biopolymeric functional groups; at the end of Section 3 in the Results and Discussion.

• 2136/sssaj2000.6451616x
• 1021/es071553d
• 1021/acs.jpcb.3c06838
• 1002/clen.201400599
• 1016/j.carbpol.2015.07.012
• 1016/j.jcis.2009.04.075

In lieu of a (too) simplified Scheme, references to the crystal structures of copper hydroxy nitrate salt and FeOOH are given.

doi:10.1155/2015/536470.

doi:10.3390/batteries9050259.

 

 

6. Make sure all abbreviations are written out in full the first time used.

Response:

The authors revised the manuscript accordingly.

7. The tiny typos and grammar errors should be corrected through the whole manuscript.

Response:

The authors revised the manuscript accordingly to improve readibility.

 

Comments on the Quality of English Language

Minor editing of English language required.

In summary, we have carried out comprehensive editing of the language, clarity, and syntax throughout to meet the high standards of this journal.  We appreciate the insightful and constructive comments provided by Reviewer #1.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors present the article a route to selective arsenate and phosphate adsorption via metal biopolymer composites. The document and topic is of relevant scientific interest, however, by doing a very general review of the manuscript, many aspects can be observed that need to be corrected.

Abstract

It is necessary to improve and restructure it

Line 13, It is necessary to change, …   spectroscopy (infrared (IR)….. by .… Fourier transform-Infrared spectroscopy (FT-IR)

Line 13, It is necessary to change, … scanning electron microscopy (SEM), …..by.… Scanning electron microscopy (SEM),

Line 14, It is necessary to change, …   Energy Dispersive X-ray (SEM-EDX))….. by.… Energy dispersive X-ray (SEM-EDX)

Line 17, It is necessary to complete,    77 mg/ with  77 mg/g

 

1. Introduction

This section should be improved

It is necessary to correct the format of references, lines: 35, 40, 46, 49, 51, 55, 59, 62, 75, 79, 85, for example:

Line 35. It is necessary to change, …  .[1]….. for ,.… [1].

 

2. Materials and Methods

It is necessary to restructured

2.1. Materials

Everything needs to be improved and restructured, because there are reagents described here that were not used in this experiment. In addition, other reagents that were used but are not described need to be described, for example the arsenate salt.

Also: NaOH solution, NaCl (aq), sodium bicarbonate buffer

The sections: 2.4. FT-IR spectroscopy, 2.5. Point of zero charge estimation (PZC), 2.6. Electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) need to be removed and described only in 2.3. Characterization

The section 2.2. Methods, should be moved after the Characterization section and renamed 2.4. Adsorption Isotherms

Line 118. It is necessary to change, … V (l)….. by .… V (L).

Line 119.   Only for phosphate?, and arsenate?    …., calculate the phosphate isotherm parameters

Line 128.   What is the meaning of phase³?.     …..adsorbent phase³.

It is necessary to correct the format of references, lines: 119, 122, 130, 152, 166, 171, 182, for example: Line 119. It is necessary to change, ….. parameters.[18] ….. by.… parameters [18].

Line 150. It is necessary to describe, …  The [NaCl].

Line 155. It is necessary to change, …... 170 mm2 ….. by.…    170 mm²

Line 167. It is necessary to describe PNP here or in the section 2.1. Materials  

 

3. Results and discussion

It is necessary to improve them.

It is necessary to correct the format of references, lines: 195, 202, 208, 212, 220 and 226,  for example:

Line 195. It is necessary to change … studies.[30–32] Therefore..… by…. studies [30–32]. Therefore...

Line 198. It is necessary to correct the number of the figure because it does not correspond.. In Figure 3 and 4, the IR spectra…

Line 206. It is necessary to change, … 1420 cm^-1 and 1350 cm^-1 and 1050 cm^-1,..… by …. 1420 cm^-1, 1350 cm^-1 and 1050 cm^-1,

Line 207. It is necessary to change, … Cu2(OH)3NO3[34,35], as,..… by …. Cu2(OH)3NO3 [34,35], as,

Line 216-217. It is necessary to change, … sodium alginate and chitosan to,..… by …. sodium alginate (NaAlg) and chitosan (Chi) to,

Line 222. It is necessary to change, Note: The PZC was obtained from Ref. [17]. by Note: ^aThe PZC was obtained from Ref. [17].

Line 237. It is necessary to change, ….in Figures S17-S48 in the SM,…. by ….. in Figures S16-S49

Line 251. It is necessary to put the reference                 ….in a previous study….

Line 267. It is suggested to change to Figure 2. SEM-EDX analysis of Al-TMC, a) Compositional mapping, b-e) elemental distribution for Al, O, C and N.

Line 274. It is suggested to change to Figure 3. SEM-EDX analysis of Cu-TMC, a) Compositional mapping, b-e) elemental distribution for O, Cu, C and N.

Line 276-279. It is necessary to complement with .. In Figure 4, is showed a comparison of two sample spots of Fe-TMC highlighting the differences in elemental distribution and heterogeneity within the materials.

Line 281. It is suggested to change to Figure 4. SEM-EDX analysis of Fe-TMC, a and f) Compositional mapping, b-e and g-j) elemental distribution for Fe, O, C and N.

Line 287. This analysis does not reveal the porosity on the otherwise relatively smooth biopolymer backbone.

Line 290-291. It is necessary to correct the numbers of the tables because it does not correspond….. summarized in Table 2, whereas … summarized in Table 3….

Line 293. It is necessary to homogenizer names of materials, for example: Al-TMC, also it is suggesting eliminate (Pi) of the next title, Adsorbate: Phosphate (Pi)

Line 300. It is necessary to homogenizer names of materials, for example: Al-TMC.

It is necessary for the authors to standardize the format of Figure, and to improve the quality of the figures.

The results of adsorption are not correctly discussed, it is necessary to improve and substantiate what is stated there.by comparing them with results already reported by other authors

4. Conclusions

It is necessary to improve them, and it is suggested that references [15,16] be eliminated and that they be used instead in the discussion of results and not in the conclusions.

References

It is necessary to homogenize format

 

In any case, the manuscript is of relevant scientific interest, however, aspects can be observed, that the authors must correct. It is necessary that the authors respect the format of this journal.

 

Author Response

Author Response to Reviewer Comments on MS ID: applsci-3163587

entitled “A route to selective arsenate adsorption in phosphate solutions via ternary metal biopolymer composites”

 

Reviewer #2

The authors present the article a route to selective arsenate and phosphate adsorption via metal biopolymer composites. The document and topic is of relevant scientific interest, however, by doing a very general review of the manuscript, many aspects can be observed that need to be corrected.

Abstract

It is necessary to improve and restructure it

Line 13, It is necessary to change, …   spectroscopy (infrared (IR)….. by .… Fourier transform-Infrared spectroscopy (FT-IR)

Line 13, It is necessary to change, … scanning electron microscopy (SEM), …..by.… Scanning electron microscopy (SEM),

Line 14, It is necessary to change, …   Energy Dispersive X-ray (SEM-EDX))….. by.… Energy dispersive X-ray (SEM-EDX)

Line 17, It is necessary to complete,    77 mg/ with  77 mg/g

 Response:

The authors restructured and emphasized the selectivity towards arsenate in presence of phosphate, while the characterisation methods were improved for clarity and brevity.

 

1. Introduction

This section should be improved

It is necessary to correct the format of references, lines: 35, 40, 46, 49, 51, 55, 59, 62, 75, 79, 85, for example:

Line 35. It is necessary to change, …  .[1]….. for ,.… [1].

 Response:
The authors now adhere to the guidelines and used the suggested citation style “[x].” throughout.

 

2. Materialsand Methods

It is necessary to restructured

2.1. Materials

Everything needs to be improved and restructured, because there are reagents described here that were not used in this experiment. In addition, other reagents that were used but are not described need to be described, for example the arsenate salt.

Also: NaOH solution, NaCl (aq), sodium bicarbonate buffer

Response: The authors addressed this concern and updated this section accordingly.

 

The sections: 2.4. FT-IR spectroscopy, 2.5. Point of zero charge estimation (PZC), 2.6. Electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) need to be removed and described only in 2.3. Characterization

The section 2.2. Methods, should be moved after the Characterization section and renamed 2.4. Adsorption Isotherms

Response:

The authors changed this section accordingly.

 

Line 118. It is necessary to change, … V (l)….. by .… V (L).

Response:

The authors changed this section accordingly.

Line 119.   Only for phosphate?, and arsenate?    …., calculate the phosphate isotherm parameters

Response:

The authors changed this section accordingly.

Line 128.   What is the meaning of phase³?.     …..adsorbent phase³.

Response:

The authors have specified the adsorbent phase and liquid phases to avoid ambiguity.

It is necessary to correct the format of references, lines: 119, 122, 130, 152, 166, 171, 182, for example: Line 119. It is necessary to change, ….. parameters.[18] ….. by.… parameters [18].

Response:

The authors changed this section accordingly

Line 150. It is necessary to describe, …  The [NaCl].

Response:

The authors changed this section accordingly

Line 155. It is necessary to change, …... 170 mm2 ….. by.…    170 mm²

Response:

The authors changed this section accordingly.

Line 167. It is necessary to describe PNP here or in the section 2.1. Materials  

 Response:

The authors changed this section accordingly as follows: “[…] and 4-nitrophenol (PNP; purity: 99%), was obtained from Alfa Aesar (MA, USA).”

 

3. Results and discussion

It is necessary to improve them.

It is necessary to correct the format of references, lines: 195, 202, 208, 212, 220 and 226,  for example:

Line 195. It is necessary to change … studies.[30–32] Therefore..… by…. studies [30–32]. Therefore...

Response:

The authors implemented the suggested changes.

Line 198. It is necessary to correct the number of the figure because it does not correspond.. In Figure 3 and 4, the IR spectra…

Response:

The authors implemented the suggested changes.

Line 206. It is necessary to change, … 1420 cm^-1 and 1350 cm^-1 and 1050 cm^-1,..… by …. 1420 cm^-1, 1350 cm^-1 and 1050 cm^-1,

Response:

The authors implemented the suggested changes.

Line 207. It is necessary to change, … Cu2(OH)3NO3[34,35], as,..… by …. Cu2(OH)3NO3 [34,35], as,

Response:

The authors implemented the suggested changes.

Line 216-217. It is necessary to change, … sodium alginate and chitosan to,..… by …. sodium alginate (NaAlg) and chitosan (Chi) to,

Response:

The authors implemented the suggested changes.

Line 222. It is necessary to change, Note: The PZC was obtained from Ref. [17]. by Note: ^aThe PZC was obtained from Ref. [17].

Response:

The authors implemented the suggested changes.

Line 237. It is necessary to change, ….in Figures S17-S48 in the SM,…. by ….. in Figures S16-S49

Response:

The authors implemented the suggested changes.

Line 251. It is necessary to put the reference                 ….in a previous study….

Response:

The authors implemented the suggested changes by adding the reference here also.

 

Line 267. It is suggested to change to Figure 2. SEM-EDX analysis of Al-TMC, a) Compositional mapping, b-e) elemental distribution for Al, O, C and N.

Line 274. It is suggested to change to Figure 3. SEM-EDX analysis of Cu-TMC, a) Compositional mapping, b-e) elemental distribution for O, Cu, C and N.

Response:

The authors agree with the suggested edits for clarity in both cases.

Line 276-279. It is necessary to complement with .. In Figure 4, is showed a comparison of two sample spots of Fe-TMC highlighting the differences in elemental distribution and heterogeneity within the materials.

Response:

The authors implemented the suggested changes.

Line 281. It is suggested to change to Figure 4. SEM-EDX analysis of Fe-TMC, a and f) Compositional mapping, b-e and g-j) elemental distribution for Fe, O, C and N.

Response:

The authors agree with the suggested change that will improve clarity.

Line 287. This analysis does not reveal the porosity on the otherwise relatively smooth biopolymer backbone.

Response:

The authors agree and provide nitrogen adsorption with BET surface area analysis to address this point with further discussion in Section 3.3 (see also BET results in Table 6).

 

Line 290-291. It is necessary to correct the numbers of the tables because it does not correspond….. summarized in Table 2, whereas … summarized in Table 3….

Response:

The authors implemented the suggested changes.

Line 293. It is necessary to homogenizer names of materials, for example: Al-TMC, also it is suggesting eliminate (Pi) of the next title, Adsorbate: Phosphate (Pi)

Line 300. It is necessary to homogenizer names of materials, for example: Al-TMC.

Response:

The authors implemented the suggested changes by using a hyphen for the materials and removed the first row in the table “Adsorbate:Phosphate”

 

It is necessary for the authors to standardize the format of Figure, and to improve the quality of the figures.

The results of adsorption are not correctly discussed, it is necessary to improve and substantiate what is stated there.by comparing them with results already reported by other authors

Response:

The authors amended the manuscript and discussed the adsorption mechanism in more detail at the end of section 3. Results and Discussion. The following references concerning metal hydroxide binding towards arsenate and phosphate were included:

• 2136/sssaj2000.6451616x
• 1021/es071553d
• 1021/acs.jpcb.3c06838
• 1002/clen.201400599
• 1016/j.carbpol.2015.07.012
• 1016/j.jcis.2009.04.075

As well, we have included Scheme 3 to further elaborate on the above discussion.

 

4. Conclusions

It is necessary to improve them, and it is suggested that references [15,16] be eliminated and that they be used instead in the discussion of results and not in the conclusions.

Repsone:

The authors removed the citation in  Section 4 of the Conclusion, as recommended.

References

It is necessary to homogenize format

Response:

The authors have harmonized the references according to the journal format.

In summary, we have carried out comprehensive editing of the language, clarity, and syntax throughout to meet the high standards of this journal.  We appreciate the insightful and constructive comments provided by Reviewer #2.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The authors reported the selective arsenate adsorption in phosphate solutions by ternary metal biopolymer composites. In my opinion, a major revision is required to improve the quality of the manuscript.

 

Specific comments:

1. In Lines 12-14, there is no need to introduce the detailed characterization method in the introduction section.

2. The molecular formula of the biopolymers should be removed to other places, and the functional groups should be labelled in Figure 1.

3. A detailed adsorption mechanism including discussion and schematic diagram should be given.

4. In Lines 57-62, more advanced references should be added, such as: “Electrostatic assembly construction of polysaccharide functionalized hybrid membrane for enhanced antimony removal, Journal of Hazardous Materials, 2021, 410, 124633; Efficient air filtration through advanced electrospinning techniques in nanofibrous Materials: A review. Separation and Purification Technology, 2024: 127773”.

5. Dose the presence of phosphate could compete the adsorption of arsenate?

6. There are a lot of small mistakes in the text, should be carefully checked and corrected. For example, some extra space. Additionally, references should be deleted in the conclusion section.

 

Comments on the Quality of English Language

The English is OK.

Author Response

Author Response to Reviewer Comments on MS ID: applsci-3163587

entitled “A route to selective arsenate adsorption in phosphate solutions via ternary metal biopolymer composites”

 

Reviewer #3

 

The authors reported the selective arsenate adsorption in phosphate solutions by ternary metal biopolymer composites. In my opinion, a major revision is required to improve the quality of the manuscript.

 

Specific comments:

1. In Lines 12-14, there is no need to introduce the detailed characterization method in the introduction section.

Response:

The authors implemented the suggested changes.

2. The molecular formula of the biopolymers should be removed to other places, and the functional groups should be labelled in Figure 1.
3. A detailed adsorption mechanism including discussion and schematic diagram should be given.

Response:

The authors added a clearer discussion (inner sphere complexation) by including Scheme 3 to the discussion and provided references that show the crystal structure of copper hydroxy nitrate salt and FeOOH:

doi:10.1155/2015/536470.

doi:10.3390/batteries9050259.

 

4. In Lines 57-62, more advanced references should be added, such as: “Electrostatic assembly construction of polysaccharide functionalized hybrid membrane for enhanced antimony removal, Journal of Hazardous Materials, 2021, 410, 124633; Efficient air filtration through advanced electrospinning techniques in nanofibrous Materials: A review. Separation and Purification Technology, 2024: 127773”.

 

Response:

The authors added the suggested reference at this position as it pertains to anchored iron nanoparticles.

• 2136/sssaj2000.6451616x
• 1021/es071553d
• 1021/acs.jpcb.3c06838
• 1002/clen.201400599
• 1016/j.carbpol.2015.07.012
• 1016/j.jcis.2009.04.075

Further, in addition to referencing inner sphere coordination, references to the crystal structures of copper hydroxy nitrate salt and FeOOH are now given.

• doi:10.1155/2015/536470.
• doi:10.3390/batteries9050259.

 

1. Dose the presence of phosphate could compete the adsorption of arsenate?

Response:

The authors clarified the manuscript (abstract, conclusion) to highlight this effect. The presence of phosphate reduces the adsorption capacity towards arsenate mostly for Al-TMC, to a much lesser extent for both Cu-TMC and Fe-TMC, respectively.

 

2. There are a lot of small mistakes in the text, should be carefully checked and corrected. For example, some extra space. Additionally, references should be deleted in the conclusion section.

Response:

The authors improved the manuscript to address these issues.

In summary, we have carried out comprehensive editing of the language, clarity, and syntax throughout to meet the high standards of this journal.  We appreciate the insightful and constructive comments provided by Reviewer #3.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors revised the manuscript carefully, and I agreed to accept it.