Combining Ultraviolet Photolysis with In-Situ Electrochemical Oxidation for Degrading Sulfonamides in Wastewater
Round 1
Reviewer 1 Report
The authors presented ultraviolet (UV) photolysis combination with an electrochemical oxidation process to degrade three kinds of veterinary sulfonamide. The treatment was applied using a flat ceramic microfiltration membrane to study the effects of photocatalysts. In this paper, the effectiveness of degradation of the three sulfonamides was evaluated under different conditions.
- The information and literatures in the texts need to include up-to-date literature including “Zhang, Shunxi, Xiaofeng Pang, Zhen Yue, Yeheng Zhou, Hongtao Duan, Wenjuan Shen, Jianfen Li, Yulan Liu, and Qunpeng Cheng. "Sulfonamides removed from simulated livestock and poultry breeding wastewater using an in-situ electro-Fenton process powered by photovoltaic energy." Chemical Engineering Journal 397 (2020): 125466”, “Shrestha, Bishwash, Mohammadamin Ezazi, Seyed Vahid Rad, and Gibum Kwon. "Predicting kinetics of water-rich permeate flux through photocatalytic mesh under visible light illumination." Scientific reports 11, no. 1 (2021): 1-9”. “Ganzenko, Oleksandra, David Huguenot, Eric D. Van Hullebusch, Giovanni Esposito, and Mehmet A. Oturan. "Electrochemical advanced oxidation and biological processes for wastewater treatment: a review of the combined approaches." Environmental Science and Pollution Research 21, no. 14 (2014): 8493-8524”. “Ezazi, Mohammadamin, Bishwash Shrestha, Sun‐I. Kim, Bora Jeong, Jerad Gorney, Katie Hutchison, Duck Hyun Lee, and Gibum Kwon. "Selective Wettability membrane for continuous oil− water separation and in situ visible light‐driven photocatalytic purification of water." Global Challenges 4, no. 10 (2020): 2000009”.
- Page 3, figure 1, The authors provided an explanation for figure 1 (a), they should provide a description for figure 1 (b) as well. Also, they should explain why they chose initial PH=8.3? what will happen for other PH values?
- Page 4, figure 2 (a); According to the figure, with aeration at 30 L/min, the k value increased for SMM and SMX by increasing chloride dosage from 20 to 45 (mg/L) then it decreased, I am wondering if you make an assumption for this or elaborate it.
- Page 6, the authors mentioned that “As the initial pH increased, the SMZ degradation efficiency followed a similar trend in the three systems, with a rapid increase to reach an optimal value at pH 8.3 followed by a decrease”. Please elaborate this sentence and make a discussion on that.
- Page 6, there is type; figure 7b should be changed to figure 5b.
Author Response
Dear Reviewer,
Thank you for your comments concerning our manuscript entitled “Combining Ultraviolet Photolysis with In-situ Electrochemical Oxidation for Degrading Sulfonamides in Wastewater” (ID: catalysts-1794420). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied comments carefully and have made correction which we hope to meet with approval. Revised portions are marked with “Track Changes” in the paper. The main corrections in the paper and the responds to the comments are in coverletter.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper describes oxidation of harmful organics by using couple of UV photolysis and electrochemical-oxidation. The authors found that the proposed system is better method compared with photocatalytic decomposition. This is very interesting.
However, very harmful UVC was used among three types of UV light (UVA, UVB, and UVC). Furthermore most of the UVC from sun does not reach the surface of the earth, indicating that sunlight may not be useful for this technique. (This technology may be useful under only UVC irradiation.) Because some readers might confuse, the authors should clearly write (in the abstract) that UVC was utilized among three types of UV lights.
Except for this point, following points should be revised for the readers to understand the contents well before publication.
1) Experimental method for TiO2 (ZnO) photocatalysis is not clear. The method should be clearly written.
2) Instead of UVC, the data under UVA should be evaluated. And the photocatalytic activity under UVA irradiation should be measured. This is because UVA is less harmful and TiO2 can use this light for photocatalysis.
Author Response
Dear Reviewer,
Thank you for your comments concerning our manuscript entitled “Combining Ultraviolet Photolysis with In-situ Electrochemical Oxidation for Degrading Sulfonamides in Wastewater” (ID: catalysts-1794420). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied comments carefully and have made correction which we hope to meet with approval. Revised portions are marked with “Track Changes” in the paper. The main corrections in the paper and the responds to the comments are in coverletter.
Author Response File: Author Response.pdf
