Pyrolysis of Aesculus chinensis Bunge Leaves as for Extracted Bio-Oil Material
, Qian Ma 1,†, Guanyan Li 1,†, Junwei Lou 2,*, Xiangmeng Chen 1, Yifeng He 1 and WanXi Peng 1,*
Round 1
Reviewer 1 Report
The manuscript entitled “Pyrolysis of Aesculus chinensis Bunge leaves as for Bio-oil and Biofuel Raw Material” refers to composition and potential application of Aesculus chinensis Bunge leaves. The Authors studied the Aesculus chinensis Bunge leaves by chromatography, TGA and FT-IR methods.
Manuscript is interesting, well-written and refers to actual problem of agricultural and forestry waste, resources of renewable energy and bioactive components obtaining.
Nevertheless, the described studies are very preliminary, the conclusions are very general.
I have a few comments and suggestions.
1. Why do authors choose Aesculus chinensis Bunge leaves for studies, exactly?
2. Is Aesculus chinensis Bunge the local plant or is it widely spreaded?
3. What is the content of active substances for predicted application in biological medicine, and as chemical crude materials and industrial raw material reagents?
4. Is there the efficient method of the separation these compounds? Is it an economic process?
5. In Experimental Part, the experimental methods should be described in details.
Author Response
Manuscript Number: polymers-1991002
Title: Pyrolysis of Aesculus chinensis Bunge leaves as for Extracted Bio-oil Material
Dear respected editor and reviewers, we would like to express our sincere gratitude to you for writing us the following constructive comments on our manuscript. Also, we appreciate very much for your willingness to check and help to improve the overall contents and quality of our manuscript with your precious time. Thank you so much for your comments and advice. We have made our best efforts to revise and improve our manuscript in an effort to acknowledge the reviewers’ comments accordingly. The comments from the reviewers are retyped below in italics, our responses are typed in normal black font, and the modifications done to the manuscript are also shown in red font. Thank you very much.
Comments from Reviewers
Reviewer #1:
The manuscript entitled “Pyrolysis of Aesculus chinensis Bunge leaves as for Bio-oil and Biofuel Raw Material” refers to composition and potential application of Aesculus chinensis Bunge leaves. The Authors studied the Aesculus chinensis Bunge leaves by chromatography, TGA and FT-IR methods.
Manuscript is interesting, well-written and refers to actual problem of agricultural and forestry waste, resources of renewable energy and bioactive components obtaining.
Nevertheless, the described studies are very preliminary, the conclusions are very general.
I have a few comments and suggestions.
Answer: We thank you for your careful review and for given us a possibility to improve the quality of our manuscript. We revised the manuscript accordingly and detailed corrections are listed below point by point.
Q1. Why do authors choose Aesculus chinensis Bunge leaves for studies, exactly?
Answer: We thank the reviewer very much for the comments. In the implementation of national forest storage project, a large area of mixed or pure buckeye forest has been planted in Henan Province, China, which requires a large amount of funds for cultivation every year, and does not produce benefits in the long term, leading to difficulties in the management of forest farms or enterprises. As buckeye is a small tree species, there are few research results, resulting in serious waste of resources. Aiming at the dilemma of resource utilization of buckeye, this study takes leaves of buckeye as the research object to explore its resource utilization and application prospect.
Q2. Is Aesculus chinensis Bunge the local plant or is it widely spreaded?
Answer: We thank the reviewer very much for the comments. Aesculus chinensis Bunge was widely distributed and widely cultivated locally.
Action: “......A. Bunge species are widely distributed around the world with more than 30 species, of which 16 species exist in China [21]......So far, XiXia county has developed A. Bunge nursery base of 4000 mu, stored seedlings of 62 million, and annual sales of more than 3 million, and the total benefit of 60 million yuan.”
Q3. What is the content of active substances for predicted application in biological medicine, and as chemical crude materials and industrial raw material reagents?
Answer: We thank the reviewer very much for the comments. The detection results obtained by PY/GC−MS can be used in biomedicine accounted for 15.78%, including Batilol, Pregnenolone, Benzoic acid, etc. The remaining 84.22% is basically used in the chemical industry, and there are many ingredients that can be used as chemical and industrial raw materials at the same time, such as Acetic acid, Formic acid, Acetone, etc.
Action: “The results of PY/GC−MS showed that the pyrolysis products could be used in biomedicine for 15.78%, including Batilol, Pregnenolone, Benzoic acid, etc. The remaining 84.22% is basically used in the chemical industry, and there are many ingredients that can be used as chemical and industrial raw materials at the same time, such as Acetic acid, Formic acid, Acetone, etc (see Table S3).”
Q4. Is there the efficient method of the separation these compounds? Is it an economic process?
Answer: We thank the reviewer very much for the comments. Most common methods including extraction, membrane separation, filtration, chromatography, etc. can be used to purify and purify compounds. This is an economical process because these methods can be done in ordinary organic laboratories and the experimental materials required are not expensive.
Q5. In Experimental Part, the experimental methods should be described in details.
Answer: We thank the reviewer very much for the additional proposal. We have added the full experimental method in the manuscript
Action:
“ 2.2. Experiment Methods
FT−IR Analysis
FT−IR spectra of ethanol and methanol extract samples were detected on Thermo Fisher Scientific iS10 (USA) instrument. A thin potassium bromide (KBr) disk was prepared from a mixture of KBr and the catalyst–wood samples at a ratio of 70:1 using mortar and pestle. The KBr disk was then loaded into an FT−IR spectrophotometer at wavelengths from 400 cm−1 to 4000 cm−1 for 64 scans [27].
TGA Analysis
TGA analysis of A. Bunge leaves sample powder was performed on STA8000 (USA) instrument. The analysis settings were as follows: the temperature rises from 0 oC to 300 oC, nitrogen gas (N2) as a carrier gas with a 60 mL/min release rate [28].
GC−MS Analysis
The chemical composition of ethanol and methanol extract samples from A. Bunge leaves samples were analyzed by GC−MS Agilent 7890B−5977A (USA) instrument. A HP−5MS column (30 m × 250 μm × 0.25 μm) and an elastic quartz capillary column were used, with a carrier gas of high purity helium at a flow rate of 1 mL/min and a split ratio of 2:1. The temperature program for GC started at 50 oC and increased to 250 oC at a rate of 8 oC/min, followed by a further increase to 280 oC at a rate of 5 oC/min. The entire MS program scanned for a mass range of 30−600 amu with an ionization voltage of 70 eV and an ionization current of 150 μA. The ion source and quadrupole temperatures were set to 230 and 150 oC, respectively [29].
PY/GC−MS Analysis
A. Bunge leaves sample powder was analyzed on pyrolysis CDS 5000−Agilent 7890B−5977A ISQ (USA) instrument. The sample was pyrolyzed at 950 oC with a heating rate of 20 oC/MS. The gas produced in the pyrolysis process was then injected in the GC−MS analyzer. The analysis settings for the GC−MS were as follows: TR–5MS column with a capillary size of 0.25 µm × 0.25 mm × 30 m at a 28–500 amu scanning range; shunt rate at 50 mL/min; split ratio at 50:1; temperature setting in two stages (increase rate of 5 oC/min from 40−120 oC and increase rate of 10 oC/min from 120−200 oC)[30]. ”
Once again, the authors are thankful to the Editor and Reviewers for providing us valuable feedback/suggestions on the manuscript to improve. We have thoroughly and carefully revised the relevant sections in the manuscript in accordance with the reviewers’suggestions. We hope that the reviewers will be satisfied with the updated version of the manuscript.
Best regards,
The authors
Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear author,
This paper presents an interesting topic related to the SDGs.
But a lot of improvement is needed. The title also should be adjusted so that it could reflect the content. This paper only analysed the bio compounds available in the raw material. There is no further testing done on the oil produced. So, to claim it as 'biofuel' is not suitable. There is also no comparative study performed to justify the results and conclusions.
Please find the attached file for detailed comments.
Thank you.
Comments for author File: 
Comments.pdf
Author Response
Manuscript Number: polymers-1991002
Title: Pyrolysis of Aesculus chinensis Bunge leaves as for Extracted Bio-oil Material
Dear respected editor and reviewers, we would like to express our sincere gratitude to you for writing us the following constructive comments on our manuscript. Also, we appreciate very much for your willingness to check and help to improve the overall contents and quality of our manuscript with your precious time. Thank you so much for your comments and advice. We have made our best efforts to revise and improve our manuscript in an effort to acknowledge the reviewers’ comments accordingly. The comments from the reviewers are retyped below in italics, our responses are typed in normal black font, and the modifications done to the manuscript are also shown in red font. Thank you very much.
Comments from Reviewers
Reviewer #2:
Dear author,
This paper presents an interesting topic related to the SDGs.
But a lot of improvement is needed. The title also should be adjusted so that it could reflect the content. This paper only analysed the bio compounds available in the raw material. There is no further testing done on the oil produced. So, to claim it as 'biofuel' is not suitable. There is also no comparative study performed to justify the results and conclusions.
Please find the attached file for detailed comments.
Thank you.
Answer: We thank you for your careful review and for given us a possibility to improve the quality of our manuscript. We revised the manuscript accordingly and detailed corrections are listed below point by point.
Q1. Page 1/ Line 18：writing error “evidencefor”
Answer: We thank the reviewer very much for the comments. We have corrected it.
Action: “The active components of A. Bunge leaves supply scientific evidence for the exploration and exploitation of this plant.”
Introduction section
Q1. In this section, there is a lack of information about the main subject, Aesculus chinensis.
The author should include more information about this plant.
Answer: We thank the reviewer very much for the supplement. We have added more information about Aesculus chinensis Bunge to the manuscript.
Action: “Aesculus chinensis Bunge（A. Bunge) is a tall deciduous tree and is recognized as one of the four beautiful street trees in the world. A. Bunge species are widely distributed around the world with more than 30 species, of which 16 species exist in China [21]. A. Bunge is an important medicinal tree species in China and can be used to treat blood circulation and edema [22]. More than 210 chemical components were isolated from A. Bunge, including other compounds such as triterpenoids, flavonoids and sterols [23]. Escin has significant antiviral, anti-inflammatory and other effects, which can be used to study the antitumor activity of bacterial biotransformation products in the human intestine [24]. ”
Q2. For example, What composition could be beneficial for future applications? How much biomass from this plant is available to ensure it is applicable for the industry? How about other research that had been done?
Answer: We thank the reviewer very much for the supplement. We have added in the manuscript.
Action: “ In recent years, the advantages of A. Bunge resources have been discovered in Xixia County (China). So far, XiXia county has developed A. Bunge nursery base of 4000 mu, stored seedlings of 62 million, annual sales of more than 3 million, and the total benefit of 60 million yuan.It plays a very important role in expanding the forestry industry chain and improving the comprehensive benefits of forestry.”
Q3. The justification for applying pyrolysis must be included in this part.
These are important to evaluate the significance of the study.
Answer: We thank the reviewer very much for the supplement. We have added information about pyrolysis.
Action: “ However, there is less research on A. Bunge as a potential biomass energy source. The wide range of uses of biomass as a feedstock has been vigorously developed worldwide, and these materials can be converted into different biomass energy sources by biochemical or thermochemical means (combustion, gasification, pyrolysis and liquefaction) [25]. Pyrolysis as a high-efficiency and high net calorific value method for producing bioenergy, especially in pyrolysis bio-oil, has attracted great attention from the society [26].”
Q4. The author also should highlight the novelty of this study.
Answer: We thank the reviewer very much for the supplement. We have added the novelty of this study in the manuscript.
Action: “......the development potential of bio-oil. As far as we know, this is also the first time to combine pyrolysis technology with A. Bunge leaves combine innovative methods. Develop comprehensive high value-added applications......”
Q5. The continuity of the information in the text is also not smooth. Please rewrite with a more suitable conjunctive to improve the smoothness of the story.
Answer: We thank the reviewer very much for the supplement. We have made changes to the manuscript.
Action: Since this change involves many paragraphs, please see our changes in the manuscript.
Sample sources
Q1. Since this paper highlighted biomass and waste utilization, why did the author not use the dried leaves that had been fall on the ground for the experiment?
Are there any differences if we use fresh green leaves with dried fallen leaves?
The author should include more information about this plant.
Answer: We thank the reviewer very much for the comments. In the past, most of the research on A. Bunge was based on its fruit, which has medicinal effects. We also wanted to know if the active ingredients in its leaves also had medicinal effects, so we chose fresh leaves. Fresh leaves are vacuum-dried and become dry leaves, which can be studied at the same time. We've added more information about A. Bunge to the manuscript.
Action: “Aesculus chinensis Bunge（A. Bunge) is a tall deciduous tree and is recognized as one of the four beautiful street trees in the world. A. Bunge species are widely distributed around the world with more than 30 species, of which 16 species exist in China [21]. A. Bunge is an important medicinal tree species in China and can be used to treat blood circulation and edema [22]. More than 210 chemical components were isolated from A. Bunge, including other compounds such as triterpenoids, flavonoids and sterols [23]. Escin has significant antiviral, anti-inflammatory and other effects, which can be used to study the antitumor activity of bacterial biotransformation products in the human intestine [24].”
Q2. I understand that the fresh leaves will undergo vacuum drying, but this will not tackle the main issue highlighted, “utilizing biomass or waste”.
Answer: We thank the reviewer very much for the comments. The main purpose of our study is to start with A. Bunge leaves were the subject of research to explore whether A. Bunge leaves have the potential to extract bio-oil and be used as a new biomass energy source. In the following study, we will quantitative analysis quantitative analysis for the bio-oil produced from A. Bunge leaves.
Q3. What method is used for powder preparation?
What is the size of the powder?
What is the protocol for the extraction? How many samples were used? Temperature? Pressure? Time?
Answer: We thank the reviewer very much for the supplement. We have supplemented in the manuscript.
Action: “ Aesculus chinensis Bunge leaves (A. Bunge leaves) were obtained from the Xixia County, Nanyang City in Henan Province. The fresh leaves are first vacuum-dried, then the dried leaves are powdered with a powder beater and sieved with a 120 mesh screen. Active compounds were extracted by mixing approximately 10 g of powder sample with two different organic solvents (ethanol and methanol), the ratio of powder to organic solvent is 1:30. ”
Experiment Methods
Page 3
Supplementary file page 1
Q1. For a scientific research paper, the methodology must be detailed so that it can be re-doing by other researchers.
Answer: We thank the reviewer very much for the comments. We have supplemented methods in the manuscript.
Action: “ 2.2. Experiment Methods
FT−IR Analysis
FT−IR spectra of ethanol and methanol extract samples were detected on Thermo Fisher Scientific iS10 (USA) instrument. A thin potassium bromide (KBr) disk was prepared from a mixture of KBr and the catalyst–wood samples at a ratio of 70:1 using mortar and pestle. The KBr disk was then loaded into an FT−IR spectrophotometer at wavelengths from 400 cm−1 to 4000 cm−1 for 64 scans [27].
TGA Analysis
TGA analysis of A. Bunge leaves sample powder was performed on STA8000 (USA) instrument. The analysis settings were as follows: the temperature rises from 0 oC to 300 oC, nitrogen gas (N2)as a carrier gas with a 60 mL/min release rate [28].
GC−MS Analysis
The chemical composition of ethanol and methanol extract samples from A. Bunge leaves samples were analyzed by GC−MS Agilent 7890B−5977A (USA) instrument. A HP−5MS column (30 m × 250 μm × 0.25 μm) and an elastic quartz capillary column were used, with a carrier gas of high purity helium at a flow rate of 1 mL/min and a split ratio of 2:1. The temperature program for GC started at 50 oC and increased to 250 oC at a rate of 8 oC/min, followed by a further increase to 280 oC at a rate of 5 oC/min. The entire MS program scanned for a mass range of 30−600 amu with an ionization voltage of 70 eV and an ionization current of 150 μA. The ion source and quadrupole temperatures were set to 230 and 150 oC, respectively [29].
PY/GC−MS Analysis
- Bunge leaves sample powder was analyzed on pyrolysis CDS 5000−Agilent 7890B−5977A ISQ (USA) instrument. The sample was pyrolyzed at 950 oC with a heating rate of 20 oC/MS. The gas produced in the pyrolysis process was then injected in the GC−MS analyzer. The analysis settings for the GC−MS were as follows: TR–5MS column with a capillary size of 0.25 µm × 0.25 mm × 30 m at a 28–500 amu scanning range; shunt rate at 50 mL/min; split ratio at 50:1; temperature setting in two stages (increase rate of 5 oC/min from 40−120 oC and increase rate of 10 oC/min from 120−200 oC)[30]. ”
Q2. In this paper, the method is too brief.
The author should include details with references
Answer: We thank the reviewer very much for the supplement. We have supplemented methods and references in the manuscript.
Action: Same as above
Q3. The pyrolysis process must be specified. All parameters must be defined.
Answer: We thank the reviewer very much for the supplement. We have added the complete pyrolysis process.
Action: “
PY/GC-MS Analysis
- Bunge leaves sample powder was analyzed on pyrolysis CDS 5000−Agilent 7890B−5977A ISQ (USA) instrument. The sample was pyrolyzed at 950 oC with a heating rate of 20 oC/MS. The gas produced in the pyrolysis process was then injected in the GC−MS analyzer. The analysis settings for the GC−MS were as follows: TR–5MS column with a capillary size of 0.25 µm × 0.25 mm × 30 m at a 28–500 amu scanning range; shunt rate at 50 mL/min; split ratio at 50:1; temperature setting in two stages (increase rate of 5 oC/min from 40−120 oC and increase rate of 10 oC/min from 120−200 oC)[30].”
Q4. Are there any manipulative variables involved?
Answer: We thank the reviewer very much for the comments. Without any manipulative variables were involved in this study.
Q5. The experiment procedures also must be written in order. Not just in a general form. Including a figure for the overall procedures will help the readers to understand the process.
Answer: We thank the reviewer very much for the comments. Our experimental procedure has been written in order.
Action: “2.2. Experiment Methods
FT−IR Analysis
FT−IR spectra of ethanol and methanol extract samples were detected on Thermo Fisher Scientific iS10 (USA) instrument. A thin potassium bromide (KBr) disk was prepared from a mixture of KBr and the catalyst–wood samples at a ratio of 70:1 using mortar and pestle. The KBr disk was then loaded into an FT−IR spectrophotometer at wavelengths from 400 cm−1 to 4000 cm−1 for 64 scans [27].
TGA Analysis
TGA analysis of A. Bunge leaves sample powder was performed on STA8000 (USA) instrument. The analysis settings were as follows: the temperature rises from 0 oC to 300 oC, nitrogen gas (N2)as a carrier gas with a 60 mL/min release rate [28].
GC−MS Analysis
The chemical composition of ethanol and methanol extract samples from A. Bunge leaves samples were analyzed by GC−MS Agilent 7890B−5977A (USA) instrument. A HP−5MS column (30 m × 250 μm × 0.25 μm) and an elastic quartz capillary column were used, with a carrier gas of high purity helium at a flow rate of 1 mL/min and a split ratio of 2:1. The temperature program for GC started at 50 oC and increased to 250 oC at a rate of 8 oC/min, followed by a further increase to 280 oC at a rate of 5 oC/min. The entire MS program scanned for a mass range of 30−600 amu with an ionization voltage of 70 eV and an ionization current of 150 μA. The ion source and quadrupole temperatures were set to 230 and 150 oC, respectively [29].
PY/GC−MS Analysis
- Bunge leaves sample powder was analyzed on pyrolysis CDS 5000−Agilent 7890B−5977A ISQ (USA) instrument. The sample was pyrolyzed at 950 oC with a heating rate of 20 oC/MS. The gas produced in the pyrolysis process was then injected in the GC−MS analyzer. The analysis settings for the GC−MS were as follows: TR–5MS column with a capillary size of 0.25 µm × 0.25 mm × 30 m at a 28–500 amu scanning range; shunt rate at 50 mL/min; split ratio at 50:1; temperature setting in two stages (increase rate of 5 oC/min from 40−120 oC and increase rate of 10 oC/min from 120−200 oC)[30].”
Q6. What is ABL in Table S3?
Answer: We thank the reviewer very much for the comments. Due to a writing error, we have made changes and will upload the supporting materials again.
Action: “Table S3 Pyrolysis/Gas chromatography-mass spectroscopic analysis of A. Bunge leaves”
Q7. Since the method is not clear, an honest judgment cannot be made by the reviewer.
Major improvement must be made.
Please include all references accordingly.
Answer: We thank the reviewer very much for the comments. We have supplemented methods and references in the manuscript.
Action: “2.2. Experiment Methods
FT−IR Analysis
FT−IR spectra of ethanol and methanol extract samples were detected on Thermo Fisher Scientific iS10 (USA) instrument. A thin potassium bromide (KBr) disk was prepared from a mixture of KBr and the catalyst–wood samples at a ratio of 70:1 using mortar and pestle. The KBr disk was then loaded into an FT−IR spectrophotometer at wavelengths from 400 cm−1 to 4000 cm−1 for 64 scans [27].
TGA Analysis
TGA analysis of A. Bunge leaves sample powder was performed on STA8000 (USA) instrument. The analysis settings were as follows: the temperature rises from 0 oC to 300 oC, nitrogen gas (N2)as a carrier gas with a 60 mL/min release rate [28].
GC−MS Analysis
The chemical composition of ethanol and methanol extract samples from A. Bunge leaves samples were analyzed by GC−MS Agilent 7890B−5977A (USA) instrument. A HP−5MS column (30 m × 250 μm × 0.25 μm) and an elastic quartz capillary column were used, with a carrier gas of high purity helium at a flow rate of 1 mL/min and a split ratio of 2:1. The temperature program for GC started at 50 oC and increased to 250 oC at a rate of 8 oC/min, followed by a further increase to 280 oC at a rate of 5 oC/min. The entire MS program scanned for a mass range of 30−600 amu with an ionization voltage of 70 eV and an ionization current of 150 μA. The ion source and quadrupole temperatures were set to 230 and 150 oC, respectively [29].
PY/GC−MS Analysis
- Bunge leaves sample powder was analyzed on pyrolysis CDS 5000−Agilent 7890B−5977A ISQ (USA) instrument. The sample was pyrolyzed at 950 oC with a heating rate of 20 oC/MS. The gas produced in the pyrolysis process was then injected in the GC−MS analyzer. The analysis settings for the GC−MS were as follows: TR–5MS column with a capillary size of 0.25 µm × 0.25 mm × 30 m at a 28–500 amu scanning range; shunt rate at 50 mL/min; split ratio at 50:1; temperature setting in two stages (increase rate of 5 oC/min from 40−120 oC and increase rate of 10 oC/min from 120−200 oC)[30].”
Q8. What is the form of sample used for pyrolysis?
Is it the powder or the extract (liquid) from the ethanol and methanol extraction?
Answer: We thank the reviewer very much for the comments. The sample used for pyrolysis is A. Bunge leaves powder after vacuum drying and sieving.
Q9. If you used the extract (liquid) for the pyrolysis, please justify why? Since pyrolysis itself can turn the solid sample into bio-oil directly, right? So why do we need separate extraction?
Would the cost increase if extraction and pyrolysis were used together?
Answer: We thank the reviewer very much for the comments. We use solid powder for pyrolysis. In this study, using both extraction and pyrolysis did not increase the cost. Because we use the extraction method in order to study the active ingredients of the A. Bunge leaves. Pyrolysis methods were used in order to explore the potential of extracting bio-oil from A. Bunge leaves.
Q10. Or methanol and ethanol are used for pre-treatment? Not extraction?
Answer: We thank the reviewer very much for the comments.We use organic solvents methanol and ethanol for extraction, and the extract was detected using GC−MS. Pyrolysis uses solid powder, which was detected using Py/GC−MS. The samples form used for GC−MS and Py/GC−MS are different.
Q11. These questions come out due to the unclear methods written in the text.
Answer: We thank the reviewer very much for the comments. We have added detailed detection methods to the manuscript.
Action: Please see our changes in the manuscript.
Results:
Q1. For the FT-IR, is the sample used only from the extraction, not pyrolysis?
Answer: We thank the reviewer very much for the comments. FT–IR spectroscopy uses extracted samples of ethanol and methanol.
Action: “
FT–IR Analysis
FT–IR spectra of ethanol and methanol extract samples ......”
Q2. For the TGA, samples at which stage was used? Is it from ethanol or methanol?
Answer: We thank the reviewer very much for this question. TGA analysis uses solid powder samples.
Action: “
TGA Analysis
TGA analysis of A. Bunge leaves sample powder ......”
Q3. Is the GSMS using the sample as FT-IR?
Answer: We thank the reviewer very much for the comments. Both GC–MS and FT–IR test samples are organic solvent extracts (ethanol and methanol).
Q4. From the results, does the author try to compare the effectiveness of extraction with pyrolysis?
If yes, the author should perform all analyses (FTIR, TGA, GCMS) for oil produced from both processes.
Answer: We thank the reviewer very much for the comments. The extracts and pyrolysis products in this project belong to different studies. In this study, GC–MS analysis was used to identify the active components of ethanol and methanol extracts of A. Bunge leaves. These active components can be used in biomedical, chemical and other fields. The pyrolysis products of A. Bunge leaves were identified by PY/GC–MS detection in order to determine the potential of A. Bunge leaves to extract bio-oil as A new biomass energy source. The combined use of GC–MS and PY/GC–MS is conducive to the development of comprehensive high value-added applications of A. Bunge leaves, which can promote sustainable utilization and reduce environmental pollution.
Conclusion:
Q1. The use of “Biofuel” is not suitable and could be questionable because there is no analysis has been done on the oil produced to prove it is “biofuel”.
Please use “bio-oil” instead.
Answer: We thank the reviewer very much for the comments. We've made changes to the title.
Action: “ Pyrolysis of Aesculus chinensis Bunge leaves as for Extracted Bio-oil Material ”
Q2.“Therefore, this study showed that the combination of biomass pyrolysis technology and extract is conducive to the development and utilization of A. Bunge leaves…”
This sentence is also questionable. There are comparative results with ordinary/standard methods, so how can this conclusion be made?
There is also no quantitative analysis for the oil produced (for example, mass or volume).
In my opinion, the spectra and chromatogram from those analyses only informed about the “present” of the compound, not the “amount” of the compound.
Answer: We thank the reviewer very much for the comments. To avoid controversy, we have deleted this sentence. We obtained the relative content of compounds by identifying the chemical composition of A. Bunge leaves. The specific relative content of chemical composition is in the supporting material. The main purpose of this study is to understand whether A. Bunge leaves have the potential to extract bio-oil, so no quantitative analysis has been conducted. We have learned from the results that A. Bunge leaves can be used as raw materials for extracting bio-oil. Next, our work is to quantitative analysis for the bio-oil produced from A. Bunge leaves
Q3. The conclusion must be rewritten, make it concise and not repeat the results.
Answer: We thank the reviewer very much for the comments. We revised the whole conclusion.
Action: “In this study, the A. Bunge leaves was used as the research object to explore its potential of extracting bio-oil. The chemical composition of A. Bunge leaves identified by GC–MS was confirmed to contain a variety of healthy and beneficial chemicals, which could be used in biomedicine, industrial and chemical industries. Further analysis by PY/GC–MS showed that rapid pyrolysis products contained a large number of oxygen-containing components, including ketones, alcohols and organic acids, which were important components of bio-oil.The A. Bunge leaves could be used to extract bio-oil and had the potential to be new biomass energy source, which was conducive to the development and utilization of A. Bunge leaves. This is the first time that the pyrolysis technology is combined with A. Bunge leaves, and the extracts and pyrolysis products show the great value added products of A. Bunge leaves. Only a small number of experiments have been conducted in the laboratory so far, and the possibility of high yield of the bio-oil needs to be confirmed. Combining waste leaves with pyrolysis is an innovative method. In the future, various parameters of the pyrolysis method can be optimized to improve the pyrolysis efficiency and maximize the effect of pyrolysis to extract bio-oil.”
Once again, the authors are thankful to the Editor and Reviewers for providing us valuable feedback/suggestions on the manuscript to improve. We have thoroughly and carefully revised the relevant sections in the manuscript in accordance with the reviewers’suggestions. We hope that the reviewers will be satisfied with the updated version of the manuscript.
Best regards,
The authors
Author Response File: Author Response.docx
Reviewer 3 Report
The work would like to report the effect of a rapid pyrolysis process on the leaves of A. Bunge, but in its current form the article is very difficult to understand and evaluate. There are several deficiencies regarding the experimental procedure, data interpretation and English form.
The introduction, while reporting the fundamental information for the paper, needs to be rewritten in a clearer and more understandable form.
The experimental procedure needs to be improved by reporting some essential parameters such as how the extraction was carried out, for what time at what temperature etc..
In the analytical section, it is also important to report a characterization of the charge before and after the extraction in terms of next and ultimate analysis.
In the discussion section not only the results must be described, but also some comments and some comparisons with other biomasses should be reported.
Author Response
Manuscript Number: polymers-1991002
Title: Pyrolysis of Aesculus chinensis Bunge leaves as for Extracted Bio-oil Material
Dear respected editor and reviewers, we would like to express our sincere gratitude to you for writing us the following constructive comments on our manuscript. Also, we appreciate very much for your willingness to check and help to improve the overall contents and quality of our manuscript with your precious time. Thank you so much for your comments and advice. We have made our best efforts to revise and improve our manuscript in an effort to acknowledge the reviewers’ comments accordingly. The comments from the reviewers are retyped below in italics, our responses are typed in normal black font, and the modifications done to the manuscript are also shown in red font. Thank you very much.
Comments from Reviewers
Reviewer #3:
The work would like to report the effect of a rapid pyrolysis process on the leaves of A. Bunge, but in its current form the article is very difficult to understand and evaluate. There are several deficiencies regarding the experimental procedure, data interpretation and English form.
Answer: We thank you for your careful review and for given us a possibility to improve the quality of our manuscript. We revised the manuscript accordingly and detailed corrections are listed below point by point.
Q1. The introduction, while reporting the fundamental information for the paper, needs to be rewritten in a clearer and more understandable form.
Answer: We thank the reviewer very much for the comments. We have revised the introduction, please check.
Action: Since this change involves many paragraphs, please see our changes in the manuscript.
Q2. The experimental procedure needs to be improved by reporting some essential parameters such as how the extraction was carried out, for what time at what temperature etc.
Answer: We thank the reviewer very much for the comments. We have added the entire experimental process.
Action: “ 2.2. Experiment Methods
FT−IR Analysis
FT−IR spectra of ethanol and methanol extract samples were detected on Thermo Fisher Scientific iS10 (USA) instrument. A thin potassium bromide (KBr) disk was prepared from a mixture of KBr and the catalyst–wood samples at a ratio of 70:1 using mortar and pestle. The KBr disk was then loaded into an FT−IR spectrophotometer at wavelengths from 400 cm−1 to 4000 cm−1 for 64 scans [27].
TGA Analysis
TGA analysis of A. Bunge leaves sample powder was performed on STA8000 (USA) instrument. The analysis settings were as follows: the temperature rises from 0 oC to 300 oC, nitrogen gas (N2)as a carrier gas with a 60 mL/min release rate [28].
GC−MS Analysis
The chemical composition of ethanol and methanol extract samples from A. Bunge leaves samples were analyzed by GC−MS Agilent 7890B−5977A (USA) instrument. A HP−5MS column (30 m × 250 μm × 0.25 μm) and an elastic quartz capillary column were used, with a carrier gas of high purity helium at a flow rate of 1 mL/min and a split ratio of 2:1. The temperature program for GC started at 50 oC and increased to 250 oC at a rate of 8 oC/min, followed by a further increase to 280 oC at a rate of 5 oC/min. The entire MS program scanned for a mass range of 30−600 amu with an ionization voltage of 70 eV and an ionization current of 150 μA. The ion source and quadrupole temperatures were set to 230 and 150 oC, respectively [29].
PY/GC−MS Analysis
- Bunge leaves sample powder was analyzed on pyrolysis CDS 5000−Agilent 7890B−5977A ISQ (USA) instrument. The sample was pyrolyzed at 950 oC with a heating rate of 20 oC/MS. The gas produced in the pyrolysis process was then injected in the GC−MS analyzer. The analysis settings for the GC−MS were as follows: TR–5MS column with a capillary size of 0.25 µm × 0.25 mm × 30 m at a 28–500 amu scanning range; shunt rate at 50 mL/min; split ratio at 50:1; temperature setting in two stages (increase rate of 5 oC/min from 40−120 oC and increase rate of 10 oC/min from 120−200 oC)[30].”
Q3. In the analytical section, it is also important to report a characterization of the charge before and after the extraction in terms of next and ultimate analysis.
Answer: We thank the reviewer very much for the comments. The sample was solid before extraction and liquid after extraction, and the physical morphology of the sample changed. We analyzed the A. Bunge leaves extract active ingredients and pyrolysis products by advanced detection methods (GC−MS and PY/GC−MS) and have good application prospects in the biomedical and chemical industries, and also have the potential to extract bio-oil. At present, under the existing experimental conditions, it is temporarily impossible to characterize the changes before and after extraction, and we will focus on and deepen the research in this aspect in future research.
Q4. In the discussion section not only the results must be described, but also some comments and some comparisons with other biomasses should be reported.
Answer: We thank the reviewer very much for the comments. We have revised the discussion section.
Action: “The results of PY/GC−MS showed that the pyrolysis products could be used in biomedicine for 15.78%, including Batilol, Pregnenolone, Benzoic acid, etc. The remaining 84.22% is basically used in the chemical industry, and there are many ingredients that can be used as chemical and industrial raw materials at the same time, such as Acetic acid, Formic acid, Acetone, etc (see Table S3). Bio-oil is a complex mixture of organic components with high oxygen content, including almost all kinds of oxygen-containing organic compounds, such as ketones, organic acids, alcohols, etc. [63]. According to the statistics in Table S3, these are classified into four classes: (1) aldehydes and ketones (2) acids and esters (3) alcohols and phenols (4) hydrocarbons, with a high proportion of organic acids, aldehydes and ketones. The results of this study showed that A. Bunge leaves contained A large amount of oxygenated organic mixtures in the pyrolysis products, which indicated that A. Bunge leaves could be used as raw materials for bio-oil extraction and had the potential to extract bio-oil.”
Once again, the authors are thankful to the Editor and Reviewers for providing us valuable feedback/suggestions on the manuscript to improve. We have thoroughly and carefully revised the relevant sections in the manuscript in accordance with the reviewers’suggestions. We hope that the reviewers will be satisfied with the updated version of the manuscript.
Best regards,
The authors
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Manuscript was corrected in satisfactory way.
Author Response
Manuscript Number: polymers-1991002
Title: Pyrolysis of Aesculus chinensis Bunge leaves as for Extracted Bio-oil Material
Dear respected editor and reviewers, we would like to express our sincere gratitude to you for writing us the following constructive comments on our manuscript. Also, we appreciate very much for your willingness to check and help to improve the overall contents and quality of our manuscript with your precious time. Thank you so much for your comments and advice.
Comments from Reviewers
Reviewer #1:
Manuscript was corrected in satisfactory way..
Answer: We thank you for your careful review and for given us a possibility to improve the quality of our manuscript.
Once again, the authors are thankful to the Editor and Reviewers for providing us valuable feedback/suggestions on the manuscript to improve.
Best regards,
The authors
Author Response File: Author Response.docx
Reviewer 3 Report
Although, the paper in the reviewed version was greatly improved some issues still persist. The English form need to be further and deeply revised (for example at lines 46-47, it is not clear if it is the wheat straw or the microwave that can be used as bio-oil and have good performances). .
Again, some aspect needs to be better detailed and clarified. In particular, if I well understand, the study was made in part on the extract from the leaves, and in part on the whole leaves powder (without extraction). If it is true, it is necessary to explain the stress the reason of this choice and report a paragraph with the differences of the two valorization methods. It is also necessary to know what are the extraction yields with the two alcohols and stress a little more the differences between the use of ethanol or methanol in the extraction process.
Because the pyrolysis was made at high temperature, also TGA should be made until the same pyrolysis temperature in order to better understand the behavior and of the yields of gas, bio-oil and char that can be obtained from a pyrolysis process.
Author Response
Manuscript Number: polymers-1991002
Title: Pyrolysis of Aesculus chinensis Bunge leaves as for Extracted Bio-oil Material
Dear respected editor and reviewers, we would like to express our sincere gratitude to you for writing us the following constructive comments on our manuscript. Also, we appreciate very much for your willingness to check and help to improve the overall contents and quality of our manuscript with your precious time. Thank you so much for your comments and advice. We have made our best efforts to revise and improve our manuscript in an effort to acknowledge the reviewers’ comments accordingly. The comments from the reviewers are retyped below in italics, our responses are typed in normal black font, and the modifications done to the manuscript are also shown in blue font. Thank you very much.
Comments from Reviewers
Reviewer #3:
Q1. Although, the paper in the reviewed version was greatly improved some issues still persist. The English form need to be further and deeply revised (for example at lines 46-47, it is not clear if it is the wheat straw or the microwave that can be used as bio-oil and have good performances).
Answer: We thank you for your careful review. We have made changes in the manuscript.
Action: “ The extraction of bio-oil from wheat straw by low temperature microwave technology provides a new way to save resources.”
Q2. Again, some aspect needs to be better detailed and clarified. In particular, if I well understand, the study was made in part on the extract from the leaves, and in part on the whole leaves powder (without extraction). If it is true, it is necessary to explain the stress the reason of this choice and report a paragraph with the differences of the two valorization methods. It is also necessary to know what are the extraction yields with the two alcohols and stress a little more the differences between the use of ethanol or methanol in the extraction process.
Answer: We thank the reviewer very much for the comments. The extract samples and powder samples we used in this project are different studies. In the past, most of the studies on A. Bunge have studied its fruit, because its fruit has medicinal effects and has a good therapeutic effect. Therefore, we also wanted to know if the active ingredients in A. Bunge leaves also had medicinal effects. Therefore, we chose to study the leaves extract sample to identify the active ingredients in A. Bunge leaves extract by GC–MS analysis. The components of A. Bunge leaves' pyrolysis products were identified using PY/GC–MS detection to determine that ABunge leaves could have the potential to extract bio-oil and be used as a new biomass energy source in the future. The combination of GC–MS and PY/GC–MS was used to treat A. Bunge leaves have a more systematic and complete study to enhance the high value-added utilization range of A. Bunge leaves, so as to achieve the real waste into treasure. We have supplemented and added the extraction rates and differences of the two alcohols in the manuscript.
Action: “GC–MS results showed that 35 and 26 chemical components were identified in A. Bunge leaves ethanol and methanol extract samples (Fig. 3), and the extraction rates were 55.35% (ethanol) and 39.82% (methanol), respectively ( see the Table S1–S2 in the supporting material). Both extract samples contained seven identical chemical compositions (ethanol/methanol) including: DL-Arabinose (1.73%/4.15%), 4H-Pyran-4-one,2,3-Dihydro-3,5-Dihydroxy-6-methyl- (2.83%/1.77%), d-Mannose(1.82%/0.74%), R-Limonene (0.89%/1.15%), 5-Hydroxymethylfurfural (7.33%/9.51%), Melezitose (2.85%/1.84%), Dodecanoic acid,3-hydroxy- (0.85%/0.41%) (see the Table S1–S2). In addition, the active ingredients detected include Acetamide, 5-hydroxyethylfural, R-limonene, D-mannose and Dihydroxyacetone have good application prospects.
......
Through a detailed analysis of the detected compounds, it was shown that the A. Bunge leaves of the plant contain many healthy and beneficial chemically active ingredients. The active compounds in the extract can be widely used in biomedical, chemical and cosmetic fields. In addition, the extraction rate of ethanol is higher than that of methanol, and ethanol has fewer toxic side effects than methanol. Therefore, ethanol extraction can be preferred for future use in the pharmaceutical or cosmetic industry. GC–MS results can provide a correct scientific basis for the development and utilization of A. Bunge leaves.”
Q3. Because the pyrolysis was made at high temperature, also TGA should be made until the same pyrolysis temperature in order to better understand the behavior and of the yields of gas, bio-oil and char that can be obtained from a pyrolysis process.
Answer: We thank the reviewer very much for the supplement. With the in-depth analysis of future experiments, and we will take your suggestions to adjust the TGA temperature parameters to ensure the best results.
Once again, the authors are thankful to the Editor and Reviewers for providing us valuable feedback/suggestions on the manuscript to improve. We have thoroughly and carefully revised the relevant sections in the manuscript in accordance with the reviewers’suggestions. We hope that the reviewers will be satisfied with the updated version of the manuscript.
Best regards,
The authors
Author Response File: Author Response.docx
