New Production Route of Magnesium Hydroxide and Related Environmental Impact
Round 1
Reviewer 1 Report
There would be interest in your paper in terms of sustainability and a green chemistry approach and it is an interesting concept as a means to make flame retardents. I would like to see the following comments addressed:
Line 22, Figure 1, Line 145: Ammonia Water should be referred to as a 25% ammonia solution.
Line 38: Please write BAT in full.
Line 45: double full stop.
Line 65 - 68: This is a repetitive and I would like you to include the actual decomposition values.
Figure 1: Is there something missing from the right hand arrow at the MgOH synthesis box?
Line 82 - 84: Needs re-phrased, particularly the first part of the sentence.
Line 87: Remove 'so-called'
Line 97 - 99: It would be good to have some purity and surface area values as a comparison
Lines 114 - 137: This should be in the introduction rather than the materials and methods section
Line 140 (and through out): Please write chemical formulae for all chemicals. You switch from writing the name and the forumula and I would like to see consistency.
Lines 146 & 152: use mL and L (SI units for vlume)
Line 164: Please provide more information on this instrument.
Line 165: please state the purty of HNO3.
Line 205 - 206: the first quotation mark needs to be "cradle. Also, 'cradle to gate' refers to extraction to the factory gate. It does not take into account the consumer, or more importantly here, to waste management. You've correctly shown it in Figure 5, so maybe it's the word choice.
Figure 5: Subscripts on the chemical formula.
Line 223 & 224: This needs to be supported by external literature. You cannot simply say your method is correct and that your data is representative without supporting material.
Table 1: Should 'consumption of materials' be in bold? Also, rename Amount to Value and combine that column with the Unit column.
Line 246: You are repeating Line 223.
Line 248: Can you explain what 'material balance' is?
Figure 6: It is difficult to make out what some of the category values are. There also appears to be two "Human Toxicity" values on both columns (top box) and 2nd (Base) or 3rd (without) from bottom.
Figure 7: It would be good to include a comment about what the negative values show? For example, is that good or bad for your research.
Line 307: X on NOX should be subscript and write NM-VOC in full the first time
Table 3: CO2 and CH4 should be written with subscript numbers; What does VI refer to next to 'emissions to water'; 61,7 should be 61.7; SO2 emissions to air should not be in the 'particulate matter' section as it is a gaseous pollutant.
Table 4: All values with 'E' should be written in scientific notation, e.g. 2.64 x10-6
Figure 8: Same comment as Figure 7
Line 368: Are these the same co-products referred to in line 212? There is a difference between a by-product and a co-product, so you need to clarify what you mean. This may have implications for your findings.
Line 382: the 2 and X should be written subscript.
Author Response
Dear Reviewer, we thank you for your comments and below you will find our references to the comments made:
Remarks: Lines – 22, 38, 45, 65-68, 82-84, 87, 97-99, 114-137, 140, 146 & 152, 164, 165, 307, 382, figure 1, and table 4 - everything corrected in accordance with the recommendations and indications of the reviewer
Line 205 - 206: the analysis was carried out from the “cradle” to “gate”, as indicated on the figs. 5, without taking into account the EoL and use phase, all references to waste have been corrected in the text.
Figure 1 - corrected
Figure 5 – corrected
Line 223 & 224: The sentence: Data can be considered representative in territorial and temporal terms because they come from places where the processes are currently carried out, it is only the statement that data used are geographically and time representative for this case because they are directly from own research and not from others carried out elsewhere. What kind of literature reference should be included here?
Table 1 – corrected
Line 246 - Chapter 3 was deleted because it was indeed, by mistake, a repetition of what had been written earlier.
Line 248 – description added in 2.3 Chapter line 222.
Figure 6 - The values for the individual categories are presented in Table 2, while the cumulative indicator and the visible difference resulting from the different assumptions made in the two scenarios are shown in Figure 2. For the LCIA method used, it considers two categories of Human Toxicity impact, with a division to the effects typically associated with carcinogenic diseases and other (non-carcinogenic diseases).
Figure 7 - additional clarification added.
Figure 8 - additional clarification added.
Line 368 – corrected.
Reviewer 2 Report
Magnesium hydroxide (Mg(OH)2) nanosheets have explored the restoration and conservation of paper-based cultural archives and other applications such as CO2 reduction and Flame retardants.
the authors should include more characterizations such as XRD and TEM wich is important to understand the crystallinity and morphology
The work in this field is not new and the Authors should cite the previous work in the synthesis of (Mg(OH)2) (there is at least one paper in 2014 and another paper in 2018 directly related to synthesis and applications must be cited in this work.
The quality and the aspect ratio of the synthesized material is questionable and we couldn't call it sheets. however, the aspect ratio is compatible with the platelet.
the author should compare their results and realize the importance of using a surfactant (such as (ctab)to get a higher quality sheet with an order of magnitude higher surface area as reported previously (American Journal of Nanomaterials. 2014, 2(2), 21-25), and (BioResources volume 13, 2, 2018.
The environmental assessment of the paper looks good and capture most of the applications.
Author Response
Dear Reviewer, we thank you for your comments and below you will find our references to the comments made:
In the research, X-ray diffraction was not used to determine the phase composition of crystallites, due to the known course of the magnesium hydroxide synthesis reaction and the certainty of the obtained product. The obtained magnesium hydroxide was analyzed for chemical purity only. At the described stage of the research, it was not necessary to use a precise surface analysis metohod with the use of the TEM microscope. Observations of the obtained samples surfaces were made using the SEM technique, which is owned by the unit in which the laboratory work was carried out. The research focused on determining the specific surface area of the obtained product and the influence of the drying process on its value. The specific surface area was analyzed using the BET technique, which is an absolute method. The developed method of drying was to eliminate additional substances, such as surfactants, introduced at the stage of magnesium hydroxide synthesis and to show how the process itself affects the development of the specific surface area of the obtained product.
Round 2
Reviewer 1 Report
Thank you for addressing my comments in my original review.
