Photocatalytic Concrete Developed by Short Seedless Hydrothermal Method for Water Purification
Round 1
Reviewer 1 Report
General Comments: Stormwater runoff management and treatment are significant topics for designing the sustainable city. In this manuscript, the functionalization of two distinct concretes (red concrete and grey concrete) via short seedless hydrothermal method was explored to develop cost-effective and greener photocatalytic concretes. Two kinds of concrete with different porosity and chemical formulation were employed as substrate for ZnO NSs growth. Their photocatalytic activity for Methyl Orange and Acid Red 14 degradation in water was examined and compared to the concretes functionalized by traditional two-step hydrothermal growth. It is a meaningful manuscript for combining the fields of photocatalysis, environmental pollution control and building materials, as well as to provide a new method for water purification by photocatalytic techniques. However, there are some details needed to be improved.
1. It is noted that the tenses need to be unified, especially abstracts and prefaces. In addition, the manuscript needs careful editing, paying particular attention to English grammar, spelling and sentence structure so that the goals and results of the study are clear to the readers.
2. There are some problems in Figure 2(a), the description of the TEM images of red concrete and grey concrete by different hydrothermal routes treatment should be described more accurately. At the same time, the TEM images of the concrete without treatment were required to better confirm the successful growth of ZnO NSs on concrete substrate.
3. In Results and Discussion part (Page4, line140), “Ca(NO3)” should be corrected as “Ca(NO3)2”.
4. Line 155-156 “Through the UV-visible spectral plot with the Tauc-Lorentz model, the presence of ZnO on all samples was confirmed.” I'm curious about how you came to this decision. Please supply some explanations to support your conclusion.
5. In Photocatalytic activity evaluation part, the degradation results of methyl orange and acid red 14 are discussed, but the description of the experimental conditions for the degradation is not sufficiently precise. Please make this portion better.
Comments for author File: 
Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
In the paper entitled “Photocatalytic concrete developed by short seedless hydrothermal method for water purification”, the Authors described the environmentally friendly in situ synthesis of ZnO nanoparticles on the surface of commercially available two types of concrete to obtain the photocatalytic system. The characterization of obtained material was accompanied by photocatalytic degradation studies of two organic dyes. The obtained results seem promising and are worth publishing in Catalysts. However, a major revision is needed due to the lack of some information:
1. The Authors should determine the yield of obtained ZnO nanostructures. In addition, the surface loading of ZnO NSs on the surface of the concrete should be determined.
2. Following this issue, the Authors should assess the various amounts of substrates used in the synthetic procedure to obtain diverse loading of ZnO.
3. The Authors should explain the differences between the degradation rates in Fig. 3 in cycles 2-6. For example, in cycles 4 and 6, there is no difference in degradation rates compared to cycles 2,3, and 5. Why?
4. Abstract: please add the degradation rate to the text. There are no numerical data.
5. In Fig. 1, please add “Rc” and “GC” to the figure.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Specific Comments
1. What are the factors that influence the photocatalytic degradation of the dye? Explain more about it in the introduction part.
2. The author please add the FTIR studies to identify the surface functional groups.
3. The author should include an SEM scale bar
4. The author should include the possible Photocatalytic mechanism schematic diagram. Also, Include the different radical scavenger diagrams.
5. If possible, please include the BET analysis.
6. Conclusion should be solid
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
I have no further comments. Thank you. I accept the manuscript in its present form.
