Activated Carbon as a Cathode for Water Disinfection through the Electro-Fenton Process
Round 1
Reviewer 1 Report
Manuscript of Alshawabkeh and co-workers reports the use of granular active carbon as cathode in order to generate hydrogen peroxide and, in the presence of metal ion, Fenton process leads to the formation of hydroxylic radical. This system has been employed to reduce the amount of E.coli in the water.
The topic is interesting, the paper is well written but some points (reported below) need to be addressed before the publication. However, I think that the manuscript is not tuned with the scope of the Journal.
· Line 58: please, explain SHE
· In Table 1, how the yield of H2O2 has been calculated?
· In many graphs, the log missing in the scale. In addition, in Fig.1 the symbol of radical missing.
· By using the method here described, a concentration of Fe2+ from 0.05 to 0.4 mM is required. Is this iron concentration allowed in the common water?
· Please, explain also the meaning of CFU
· Line 174: where is eq. 10 in the main text?
· In paragraph 2.4, the authors are invited to measure the pH of the solution after the addition of carbonate ions.
Author Response
We greatly appreciate the reviewer’s recognition of the value of our study. Especially, we thank the reviewer for his/her insight on the positive comment on the novelty and written language. Please accept our sincere gratitude. Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript submitted by Chen et al. describe the use of low cost granular activated carbon (GAC) as a cathode to generate H2O2 for water disinfection through electro-Fenton process. Authors performed a detailed and systematic study by varying parameters including GAC loading, mesh size, solution pH, currents, reactor volume etc. The authors used E. coli. with various antibiotic resistance genes (ARGs) as the model pathogen to demonstrate the feasibility of this process and found that this electro-Fenton process could inactivate pathogen efficiently regardless of ARGs. The authors also carried out a techno-economic analysis and demonstrated the cost effectiveness of this process for practical water treatment application.
Overall the manuscript provides valuable informations to the readers working in this field. Manuscript is well written and presented clearly. Therefore, I recommend to publish this manuscript in catalysis in the current form.
Author Response
The authors greatly appreciate the reviewer’s opinion on recommendation of publishing our work. We especially thank the reviewer for his/her insights in that our work provides valuable information on the electro-disinfection field. Please accept our sincere gratitude.
Reviewer 3 Report
The manuscript deals with the study of electro-Fenton process for water disinfection, where activated carbon as a cathode. The Authors proposed a interesting topic for research. The abstract contains relevant information about the scope of research and results obtained. The paper is well organized and the data are well presented. The paper is publishable, but it is need to consider a few of uncertainties.
1. Hydrogen peroxide is unstable in the basic reaction environment. What was the reason for such slight differences?
2. Many publications report a negative effect of carbonate ions on the amount of hydroxyl radicals. It is interesting to note that these ions did not affect the amount of hydrogen peroxide. Please explain this (line 237-238)
3. The descriptions in the drawings are disproportionate
4. In the introduction, please elaborate the novelty of the work and indicate more clearly the necessity of conducting such research
5. In what system was process carried out? open or closed ?
Author Response
We thank the reviewer for his/her positive comments on our work. We would like to express our sincere gratitude to the reviewer for the time and efforts in reviewing our work. Detailed item-to-item responses have been included below. Please kindly check.
Author Response File: Author Response.pdf
Reviewer 4 Report
The manuscript is well written and has strength to attract broad audience. I like this manuscript and believe this should be accepted with minor revision as noted.
There is not much discussion about carbon and microstructures to related with this. May be a brief though about carbon towards water disinfection and bacteria removal will add more interest.
Some chracterization of the carbon cathode electrode should be there. The micostructures of carbon could be beneficial for Fenton reaction by providing catalytic support, easy way to reactant and product transport though accessible surface areas.
A comparison table would be interesting to show earlier reported work in this area with other forms of carbon?
Author Response
We thank the reviewer for his/her positive comments and recognition of the value in our work. Please accept our cordial gratitude for your time and efforts. Please kindly check below for our responses.
Author Response File: Author Response.pdf
