Analysis of Carbon Tetrachloride-Extractable Species from Daxing Bituminous Coal
Round 1
Reviewer 1 Report
The paper reports a study about of best extraction method of the use of Daxing Coal between three different techniques: Soxhlet extraction; Ultrasonic-assisted extraction; Microwave-assisted extraction.
My recommendation is that this work can be published after minor revisions noted:
The introduction should can be improved, It is very scarcy Sample preparations: Why did the authors use the different conditions: 60ºC, 24h, nitrogen gas stream…? The Extraction procedures should be better explained. The same applies to analytical methods. Everything must be improved for a possible reproduction of the exposed process The results and conclusions part contains a lot of information that should be better explained and more orderly to facilitate its understanding. The work carried out is very interesting but the description of it must be redrafted to promote the understanding of it.
Author Response
Response to Reviewer 1 Comments.
Dear reviewer
We appreciate your valuable suggestions, which have truly helped us to significantly improve the quality of our paper as well as strengthen the validity of our results. According to your suggestions and questions, we made some revisions in this round as follows:
Q1: Why did the authors use the different conditions: 60℃24h, nitrogen gas stream...?
R1: In order to prevent the oxidation of coal in the air during the heating process, the nitrogen gas stream flow into the tube furnace in the experiment. See Line 66
Q2: The Extraction procedures should be better explained.
R2: Lines 77-98 show the Extraction procedures.
Q3: The analytical methods should be better explained.
R3: Lines 100-113 show Analytical methods.
Q4: The results and conclusions part contains a lot of information that should be better explained and more orderly to facilitate its understanding.
R4: Lines 148-152 show the FT-IR, Lines 166-170 show the XRD, Lines 211-218 show the GC-MS analysis of extracts.
Q5: The work carried out is very interesting but the description of it must be redrafted to promote the understanding of it.
R5: We have revised the English expression of the paper.
We believe that this manuscript will be of exceptional interest to the specialist in related research field.
Best regards
Xian-Yong Wei
Prof., Dr. Eng.
School of Chemical Engineering
China University of Mining and Technology
Xuzhou 221008, Jiangsu, China
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper presents an interesting investigation into the compounds that may be extracted off of a Daxing coal sample using three different extraction methods. These methods are clearly outlined and are appropriate. GC-MS is used to identify extracted compounds and FTIR and XRD are used to characterize the unextracted residue.
Overall, the methods are sound and the conclusions match the data as presented. The results will be of interest in scientists interested in the extraction of organic compounds off of coal and related materials.
A couple of points that need revision:
The authors present their chromatograms as ion chromatograms, surely this is an error as the authors used gas chromatography not ion chromatography, the latter of which would be ill-suited to the types of compounds extracted off of the coal.
Line 191: van der Waals
Line 197: electromagnetic fields
Author Response
Response to Reviewer 1 Comments.
Dear reviewer
We appreciate your valuable suggestions, which have truly helped us to significantly improve the quality of our paper as well as strengthen the validity of our results. According to your suggestions and questions, we made some revisions in this round as follows:
Total ion chromatogram (TIC) is the total ion flow of sample obtained by GC-MS software after separation by chromatogram column. Lines 176-177 show the revision. 2. Lin 237 “Van der Waals” was revised. Line 243 “electromagnetic fields” was revised.
We believe that this manuscript will be of exceptional interest to the specialist in related research field.
Sincerely yours,
Xian-Yong Wei
Prof., Dr. Eng.
School of Chemical Engineering
China University of Mining and Technology
Xuzhou 221008, Jiangsu, China
Author Response File: Author Response.pdf
