Cleaning Phenolic Compounds Present in Water Using Salting-Out Effect with DCA-Based Ionic Liquids
Round 1
Reviewer 1 Report
Comments for author File: 
Comments.pdf
Author Response
The World Health Organization (WHO) and the European Union (EU) stablish a list of priority pollutant substances in water, in which some phenolic compounds are included, and it is fixed the limit concentration for them in wastewater in 1 mg·L-1.
Page 1 Line 27-29, The statement of WHO and EU are mentioned, however, I have not found any supporting references by WHO and EU reports. Adjust the supporting references carefully.
Response. Thank you for your comment, it was taken into account and the failure was corrected into the text. It was added the reference and a comment about the legal limit established by EPA.
The influence of the concentration of salt (K3PO4) in the extraction efficiency was evaluated. This salt was selected based on the favorable properties, such as its low price, it is a non-pollutant substance and due to the fact, that is a trivalent salt it presents stronger salting out ability than divalent or monovalent salts [32].
Page 3, Line 109-113, your selection criteria for salt K3PO4 is based on the literature ‘Role of the Hofmeister Series in the Formation of Ionic-Liquid-Based Aqueous Biphasic Systems by Shahla Shahriari’ but this salt is not present in their material selection list, however, they have cited K3PO4 in their introduction section as a discussion by another group. You might need to change the reference & needs to provide supporting references for your selection criteria of salt K3PO4.
Response. Thank you for your comment, it was taken into account the text was amended to provide supporting information and the corresponding reference was added into the text.
ILs are organic salts formed by or- 54 organic cations and organic or inorganic anions, which remain in liquid state below 373 K……
Page 2. Line 52-59, the Author needs to discuss more regarding the cationic/anionic nature of ILs, add some other characteristics of ILs, referring to few articles of MDPI like:
https://doi.org/10.3390/en15239098
https://doi.org/10.3390/polym14050984
https://doi.org/10.3390/pr9020337
Response. Thank you for your comment. It was taken into account and the text was amended and the references were added into the article.
Reviewer 2 Report
In addition to the practical approach to describing the results, it would be interesting to look at them from a theoretical point of view: to the graphs "Efficiency - initial concentration of phenolic compound" add the dependencies for Distribution coefficients. This is to draw a conclusion about how the distribution coefficient depends on the concentration of the extracted compound.
In the section “Effect of the cation structure of the IL in the extraction yield” the effect of the tail length on the distribution coefficient should be discussed with extra-references.
By design: somewhere the indices of K3PO4 are not omitted, somewhere there is no scale on the X-axis.
Author Response
In addition to the practical approach to describing the results, it would be interesting to look at them from a theoretical point of view: to the graphs "Efficiency - initial concentration of phenolic compound" add the dependencies for Distribution coefficients. This is to draw a conclusion about how the distribution coefficient depends on the concentration of the extracted compound.
Response. Thank you for your comment. In our work, the extraccion efficiencies were high, upper than 90% in most of studied systems. The partition coefficient has very high values for all concentrations and the influence on the results is not clearly seen, for this reason graphs of extraction efficiencies and final concentrations were incorporated in the work that reveal the values in which the extractions for phenols depending on the different studied parameters
In the section “Effect of the cation structure of the IL in the extraction yield” the effect of the tail length on the distribution coefficient should be discussed with extra-references.
Response. Thank you for your comment, it was taken into account and the explanation was improved and extra references were introduced.
By design: somewhere the indices of K3PO4 are not omitted, somewhere there is no scale on the X-axis.
Response. Thank you for the warning, these mistakes were amended.
Reviewer 3 Report
Cleaning Phenolic Compounds Present in Water Using Salting Out Effect with DCA Based Ionic Liquids
Olalla G. Sas is well written paper, this paper can be accepted after answering following comments.
Comment 1: Improve introduction to attract audience of this journal.
Comment 2: What is the reason to select IL ???, many other cost-effective technologies such as photodegradation, adsorption are already available.
Comment 3: K3PO4 should be studied from 10%, 20%, 30%,40%,50% concentration. Why did you start directly from 20% .
Comment 4: Give the structure of Ionic Liquids
Comment 5: Suggest the mechanism of the process???
Comment 6: Plot the graph of Intensity against wavelength.
Comment 7: Conclusion should be brief and can be improved
Comment 8: Add following latest references of Ionic liquids.
1. 1. A green approach for the multicomponent synthesis of polyhydroquinolines and 6-unsubstituted dihydropyrimidinones using novel highly proficient acidic ionic liquid [CEMIM][MSA] as a reusable catalyst Priyanka Patil a, Suresh Kadam ,Dayanand Patil , Paresh More , Catalysis Communications 170 (2022) 106500.
2. An eco-friendly innovative halide and metal-free basic ionic liquid catalyzed synthesis of tetrahydrobenzo [b] pyran derivatives in aqueous media: A sustainable protocol, Priyanka Patil, Suresh Kadam, Dayanand Patil and Paresh More, Journal of Molecular Liquids 345 (2022) 117867.
Author Response
Comment 1: Improve introduction to attract audience of this journal
Response. Thank you for your comment, it was taken into account and the introduction was improved.
Comment 2: What is the reason to select IL ???, many other cost-effective technologies such as photodegradation, adsorption are already available.
Response. Thank you for four comment. Adsorption and photodegradation are not an effective tecniques for very low concentrationse with liquid-liquid extraction it is possible to remove even concentrations below 1 ppm, and it is possible the recovery and reuse of the extraction solvent as well as the extracted compounds.
Comment 3: K3PO4 should be studied from 10%, 20%, 30%,40%,50% concentration. Why did you start directly from 20%
Response. Thank you for your comment. In our study 10% of salt was studied but for one system, [EMim][DCA] + salt + water, the two inmiscible phases were not formed, so the studied concentration were 20%, 30% and 40%, and wiht these three concentrations the extraction efficiencies were upper than 90%, so we chose not to study one more high concentration of salt because the extraction could not be improved much more.
Comment 4: Give the structure of Ionic Liquids
Response. Thank you for your comment, it was taken into account and the structure of the ionic liquids was indicated in the article.
Comment 5: Suggest the mechanism of the process???
Response. Thank you for your comment. The possible explanation of the mechanism of the process was added in the article.
Comment 6: Plot the graph of Intensity against wavelength.
Response. Thank you for your comment, it was taken into account and the graph of intensity against wavelength was added in the supplementary information
Comment 7: Conclusion should be brief and can be improved
Response. Thank you for your comment, it was taken into account.
Comment 8: Add following latest references of Ionic liquids.
Response. Thank yoy for your comment, the indicated references were added into the text.
