Valorization of Microcrystalline Cellulose Using Heterogeneous Protonated Zeolite Catalyst: An Experimental and Kinetics Approach
Round 1
Reviewer 1 Report
Jain et al. report in this article, with title "Valorization of Microcrystalline Cellulose using Heterogeneous Protonated Zeolite Catalyst: An experimental and kinetics approach", the catalytic effect in synergy with 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid. The authors characterized the catalysts through Fourier transform infrared, X-ray diffraction, temperature-programmed desorption of ammonia and BET-surface techniques. They claim that by using the ionic liquid the activation energy of formation and decomposition of the sugar, which is obtained from the reaction, is significantly reduced.
Overall, the quality of the work is enough and appropriate to be published in the journal Reactions. Some comments/suggestions/revisions to improve the paper are:
1) The affiliations of the authors are not completed. Please, check this out.
2) In point 3.1, the FTIR, XRD,...techniques must be accordingly defined (that is, with their complete name).
3) In Figure 1, concerning the FTIR analysis, what about the possible information given by the bands in the 500-300 cm-1 range?.
4) Studies performed through the SEM or XPS techniques could be useful in order to support part of the reported results.
5) In Figures 4 and 5, maybe a bars plot of the Yield vs T/°C could be more illustrative. Besides, the "a" (figure 4) and "b" (figure 5), what do they mean? They are separate figures!.
6) Please, write "+" as superscript for "H+ ions" throughout the text.
7) In page 10, line 367, the point 2 should be further explained or give some additional equations.
Author Response
Response to Reviewer's comments
Title: Valorization of Microcrystalline Cellulose using Heterogeneous Protonated Zeolite Catalyst: An experimental and kinetics approach
We appreciate the reviewers’ comments and valuable suggestions.
Reviewer #1
- The affiliations of the authors are not completed. Please, check this out.
Response: The necessary changes have been made in the revised manuscript.
- In point 3.1, the FTIR, XRD, techniques must be accordingly defined (that is, with their complete name).
Response: Fourier transforms infrared (FT-IR), X-ray diffraction analysis (XRD) defined in section 3.1 as suggested in the revised manuscript.
- In Figure 1, concerning the FTIR analysis, what about the possible information given by the bands in the 500-300 cm-1 range?
Response: Compared with the pure zeolite spectrum, there was no significant change observed for the impregnated catalyst below 500 cm-1 concerning peak intensity, broadening, or shifting. Hence, we did not include these data to depict the significant result obtained.
- In Figures 4 and 5, maybe a bars plot of the Yield vs T/°C could be more illustrative. Besides, the "a" (figure 4) and "b" (figure 5), what do they mean? They are separate figures!.
Response: Yes, the bar chart could also be used in this case. However, we wanted to show how the continuous increment of temperature affected the yield of TRS, glucose, fructose, and 5-HMF using the catalyst. The “a” in figure 4 and the “b” in figure 5 are both removed as per the suggestion.
- Please, write "+" as a superscript for "H+ ions" throughout the text
Response: The suggestion is applied.
- On page 10, line 367, point 2 should be further explained or give some additional equations.
Response: The reaction rate equations were developed based on the Saeman model considering all the model's assumptions. Primarily, the model assumes irreversible pseudo-homogeneous first-order reactions.
Reviewer 2 Report
One of the long-standing tasks in science and technology is to find efficient ways to convert cellulose into biofuel and useful environmentally friendly chemicals. In relation to this, the present study offering a new way of such conversion based on (H-ZSM-5) and Cr/H-ZSM-5 catalysts is certainly on demand. The are new interesting findings on the catalytic mechanisms of the cellulose conversion. The work employs the state-of-the-art approach in terms of scientific strategy combining both experiment and modelling, as well as the implementation with the aid of accurate sample preparation and complementary characterization techniques. The work is well arranged, clearly presented, referencing is comprehensive and up-to-dated. In my view the manuscript is suitable for publication in Reactions, if the following minor points are addressed (which I, however, do not view as mandatory). 1) Although there is no big change in the lattice structure of H-ZSM-5 and Cr/H-ZSM-5 as revealed by XRD (Fig. 2), the observed changes (peak position shift) and increase of intensity at 7-8 degrees of 2 thetha for Cr/H-ZSM-5 must have notably been reflected in FTIR spectra (given its extreme sensitivity) (Fig. 1) which, however, is not the case. This needs some explanation. 2) Is the decrease in surface area from 270 m2g-1 for H-ZSM-5 to 248 m2g-1 for Cr/H-ZSM-5 is due to simple site blocking effect by Cr? If so, it needs some estimates from structural viewpoint, even very quantitative. 3) It would be very informative to asses the state of the catalysts by FTIR and XRD before and after reaction and liquid treatment. 4) The ionic state of Cr may play an important role in catalytic performance, so it could be useful to look at this, for instance by XPS.Author Response
Response to Reviewer's comments
Title: Valorization of Microcrystalline Cellulose using Heterogeneous Protonated Zeolite Catalyst: An experimental and kinetics approach
We appreciate the reviewers’ comments and valuable suggestions.
Reviewer #2
- Although there is no big change in the lattice structure of H-ZSM-5 and Cr/H-ZSM-5 as revealed by XRD (Fig. 2), the observed changes (peak position shift) and increase of intensity at 7-8 degrees of 2 theta for Cr/H-ZSM-5 must-have notably been reflected in FTIR spectra (given its extreme sensitivity) (Fig. 1) which, however, is not the case. This needs some explanation.
Response: There is an insignificant change in the lattice structure of the zeolite after impregnating it with Cr metal which primarily is due to the small dose (<5%) of chromium metal applied as also revealed by the XRD analysis. The peak position shifts observed at 7-8 degrees in XRD were not reflected on the FTIR analysis which probably is due to the sensitivity issue, or the low dose of chromium applied to affect the internal vibrations in the framework of the zeolite structure.
- Is the decrease in surface area from 270 m2g-1 for H-ZSM-5 to 248 m2g-1 for Cr/H-ZSM-5 is due to the simple site blocking effect by Cr? If so, it needs some estimates from a structural viewpoint, even very quantitative.
Response: Yes, the decrease in the specific surface area of H-ZSM-5 is due to the partial blocking of the pore structure by chromium metal.
- It would be very informative to assess the state of the catalysts by FTIR and XRD before and after reaction and liquid treatment.
Response: Yes, in the preliminary study we have investigated the before and after reaction of the catalyst which requires further in-depth study and can not be fully covered in this research presentation.
Author Response File: 
Author Response.docx
Reviewer 3 Report
Paper entitled with “ Valorization of Microcrystalline Cellulose using Heterogeneous Protonated Zeolite Catalyst: An experimental and kinetics approach” by Samuel Kassaye, et al discuss the use of ionic liquid significantly and valorize microcrystalline cellulose (MCC) using protonated zeolite catalysts. The following comments are rising:
- Catalyst’s micro and nanostructure should Characterize using SEM images .
- XRD pattern of H-ZSM-5 and Cr/H-ZSM-5 catalysts should include planes and more discussion in these results should be provided.
- BET Analysis discussion is not sufficient, more, and deep discussion is required.
- Some English correction are needed such as capital letters in lines are existing , please revise MS English grammars .
- FTIR, XRD, BET surface area, ammonia TPD and TGA characterizations instruments models and origin of manufacture and detailed experimental conditions should be placed.
- In introduction , last paragraph : Results showed that this approach generated a 70% yield.. these should be highlighted in abstract and conclusions not in introduction section .
Author Response
Response to Reviewer's comments
Title: Valorization of Microcrystalline Cellulose using Heterogeneous Protonated Zeolite Catalyst: An experimental and kinetics approach
We appreciate the reviewers’ comments and valuable suggestions.
Reviewer #3
- Catalyst’s micro and nanostructure should be characterized using SEM images.
Response: Purpose of centrifuge process is simply ensure the enhanced purity of the hydrolysate by removing the possible suspended particles remained after the conventional filtration process and in most of the cases there was no precipitate observed after centrifugation process.
- XRD pattern of H-ZSM-5 and Cr/H-ZSM-5 catalysts should include planes and more discussion in these results should be provided.
Response: More discussion on XRD is included in the revised manuscript.
- BET Analysis discussion is not sufficient, more, and deep discussion is required.
Response: The suggestion is included in the revised manuscript.
- Some English correction are needed such as capital letters in lines are existing , please revise MS English grammars.
Response: the necessary correction and manuscript editing is done.
- FTIR, XRD, BET surface area, ammonia TPD and TGA characterizations instruments models and origin of manufacture and detailed experimental conditions should be placed.
Response: Suggestion included in the revised manuscript.
- In introduction , last paragraph : Results showed that this approach generated a 70% yield these should be highlighted in abstract and conclusions not in introduction section.
Response: as suggested, the result is highlighted in the abstract part and removed from the introduction.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
It is difficult to follow up changes in the revised manuscript there are no refer to the changes in lines or colors. In addition, authors response to catalyst’s micro and nanostructure characterization using SEM images that the purpose of centrifuge process ensures the enhanced purity of the hydrolysate . however , catalytic micro/nano structure play a vital role on that which should be highlighted, then what the aim of XRD ,FTIR, TGA analysis ?
Please highlight your response to the comments with line and red color to easy follow up ?
Author Response
Dear Reviewer #3,
We greatly appreciate your thorough review of our manuscript and suggestions to improve it.
We have incorporated all your suggestions in the revised manuscript and given below is a point wise response to your comments.
Please let us know if there’s anything else that needs our attention.
Kind regards,
Sapna
Author Response File: Author Response.docx
Round 3
Reviewer 3 Report
Authors respond to comments
