Synthesis, Characterization, and Solar Photo-Activation of Chitosan-Modified Nickel Magnetite Bio-Composite for Degradation of Recalcitrant Organic Pollutants in Water

Round 1

Reviewer 1 Report

Comments to the Author Manuscript Catalysts-1865120

 The manuscript entitled ‘Synthesis, characterization and solar photo-activation of chitosan modified nickel magnetite bio-composite for degradation of recalcitrant organic pollutants in water’ by Ara et al focuses on the synthesis of nanostructured chitosan modified nickel magnetite bio-composite and it application for the solar/photocatalytic degradation of two model azo dyes, i.e., methylene blue and methyl red. There are some points which must be edited or clarified by providing additional information or comments:

1. The authors should write the complete terms of all abbreviations (including the instruments) before the first use in the abstract and main manuscript i.e. FTIR, SEM, EDX, TGA and UV–Vis analysis in the introduction section (line #91).

2. Please add on the fig 1 (FTIR spectra) similar spectra of chitosan in order to compare.

3. EDX analysis (Fig 2) - a very conditional (not specific) type of analysis of the chemical composition of the surface. Often, spectra with different atomic abundances of elements can be obtained even from the same sample. First of all, authors have to attach an EDX mapping images. And the authors are strongly recommended to add XPS spectra to this section of revised manuscript. The XPS method is much more sensitive and more accurately determines changes in the chemical composition of samples.

4. Fig. 3 - for a more effective visual effect, authors recommended providing SEM images with more readable scale bar and other texts.

5. Please provide additionally TGA and DSC curves of chitosan on the Fig 4. and discuss it. Similar quote for the Fig 5.

6. Please revise legend on the Fig 8 due you provide 4 lines and only 3 corresponding  points in legend.

7. Authors should be more correct and give more adequate explanation about increasing of D% value with increasing of dye concentration… This effect is very well studied in various studies related to the dyes photocatalytic degradation, and in completely all studies the value of D% is decreased with an increasing of dye concentration..

8. Table 2 – please clarify details of the optimum conditions.

9. Generally I suggest to Authors to make some arranges in the discussion section:

- subsection, related to the determination of optimal pH should be discussed first.

- kinetic plots more logically placed after fig8.

10. Effect of temperature should be more discussed – please provide data on the changing of rate constants and calculate value of activation energy, enthalpy and entropy. Please refer to [1].

11. The comparative table #3 should be elaborated. Please clarify more detailed information about catalytic experiments (amount of loaded catalyst, dye concentration, type of light source, reaction time et al). Please separate MB and MR. It will be useful to add also rate constant data and activation energy values. Also please refer results of similar study [2] in this table.

12. The conclusion section should be elaborated and improved. The author should bring specific conclusions in accordance with obtained results.

13 The most important quote – English grammar have to significantly elaborated! There are a lot of typos and mistakes within all manuscript

Our decision on this manuscript – Major revision. After making all required minor changes in article it could be recommended for publication.

1.        Altynbaeva, L.S.; Barsbay, M.; Aimanova, N.A.; Jakupova, Z.Y.; Nurpeisova, D.T.; Zdorovets, M. V.; Mashentseva, A.A. A Novel Cu2O/ZnO@PET Composite Membrane for the Photocatalytic Degradation of Carbendazim. Nanomaterials 2022, 12, 1724.

2.        Mashentseva, A.A.; Barsbay, M.; Aimanova, N.A.; Zdorovets, M. V Application of Silver-Loaded Composite Track-Etched Membranes for Photocatalytic Decomposition of Methylene Blue under Visible Light. Membranes (Basel). 2021, 11, 60.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

In this manuscript, the authors address the synthesis of a new chitosan modified nickel magnetite bio-composite for degradation of recalcitrant organic pollutants in water. They carried out several reactions, providing a reasonable scope for future application of this biocomposite. This composite showed significant physicomechanical properties, and the obtained results are interesting. Nevertheless, the manuscript requires minor revisions.

1- Keywords must be revised.

2- The novelty of the present work concerning other state-of-nickel magnetite bio-composite should be highlighted in the introduction.

3- The authors have to avoid the usage of unnecessary sentences, and the quality of English has to be polished.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Authors significantly improve the quality of revised manuscript, Thus it can be recommended for acception.