Synergistic Effects of a Packed Bed Bipolar Electrolysis System Combined with Activated Carbon for Efficient Treatment of Dyeing Wastewater

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Overview and General Recommendations:

The paper aimed to evaluate the removal of Total Nitrogen and COD in dyeing wastewater using a bipolar electrochemical system, with aluminum as electrodes, and with or without a packed bed of Activated Carbon.

The paper needs minor revisions as listed below before acceptance.

Specific Comments:

1. Introduction: What is the novelty of the study or of the system?
2. "Section 3.4. Effect of AC packed under added electrolyte." The section heading is recommended to be revised. It can be misleading since the contents of the discussion involves all conditions with activated carbon. The variable under this section is the concentration of electrolyte (0, 5, and 10 mM NaCl) . Thus, it seems that the effect of the electrolyte concentration to the system with packed AC was investigated, instead of the effect of AC. The same observation/comment goes for the other subsections (3.4.1 to 3.4.3).
3. Figure 3. It is recommended to clarify what the words Non-addition mean in the  graph. The same clarification of what Non-addition is should also be done in the Abstract. 
4. Lines 408-410: "These results suggested that AC not only contributes to the physical  adsorption of organic compounds but also enhances electrochemical reactions, thereby improving the removal efficiencies of both T-N and TOC." Based on the experiment conducted and the results presented, how did the AC contribute to the enhancement of the electrochemical reactions? Or is it possible that the addition of AC only increased the removals due to the added removal mechanism of adsorption (aside from the elctrochemical processes).
5. Conclusions: The conclusions may be made more brief and concise. In the current version, the list of conclusions appear to be a discussion of the results instead of the main findings.

Comments on the Quality of English Language

The manuscript must be checked for grammatical and typographical errors.

Author Response

We sincerely appreciate your patience. The response to the review comments has been attached for your kind consideration.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

While the manuscript presents an extensive dataset on the effects of voltage, electrolyte type, and activated carbon on T-N and TOC removal, it lacks a deeper mechanistic explanation of how the packed-bed bipolar electrolysis system with AC contributes synergistically to pollutant degradation. Therefore, I recommend major revise.

 

1. Line 15: Background of this study needs to explain.
2. Line 30: What’s the impact of this study to current field?
3. Line 87: What’s the advantage of electrochemical treatment when it compares to other treatment method?
4. Line 95: Please recheck the sentence “According to [15]”
5. While the combination of electrolysis and activated carbon is not new, the paper could better emphasize what is novel about this specific system setup?
6. The proposed mechanisms for T-N and TOC removal are referenced but not experimentally verified (e.g., intermediate by-products, floc characterization).
7. Adding complementary analyses (e.g., SEM, FTIR, or zeta potential) in the work or briefly discuss this limitation.
8. The study would benefit from a brief discussion on the scalability of the packed-bed bipolar electrolysis system and its operational cost compared to conventional systems.
9. There are several minor formatting inconsistencies (e.g., line breaks, spacing, redundant hyphenations like "non-addition" which might read better as "no addition").
10. Use consistent units and symbols, e.g., mS/cm vs. mS·cm⁻¹, ppm vs. mg/L.
11. Please check all of the data in the figures, why are not there error bars?
12. Part 3: Please add more discuss to the phenomenon, especially the Part “3.4. Effect of AC packed under added electrolyte”
13. Please check Figure 4-10 of the top line.
14. There are many refs out of date even more than 15 years, please use some up to date refs
15. Language needs to re-check to needs the standards of the journal.

 

Author Response

We sincerely appreciate your patience. The response to the review comments has been attached for your kind consideration.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear authors,

 

Please find attached my comments regarding your paper :"Synergistic effects of a Packed Bed Bipolar Electrolysis System Combined with Activated Carbon for Efficient Treatment of Dyeing Wastewater"

 

Sincerely.

Comments for author File: Comments.pdf

Author Response

We sincerely appreciate your patience. The response to the review comments has been attached for your kind consideration.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

It can be accepted in present form.

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

Thank you for the opportunity to review your manuscript. After a thorough evaluation, I am pleased to inform you that your article is acceptable for publication in its current form. Congratulations on your submission.

Sincerely.