Degradation of Tetracycline Hydrochloride by a Novel CDs/g-C3N4/BiPO4 under Visible-Light Irradiation: Reactivity and Mechanism
Round 1
Reviewer 1 Report
The authors investigated "Degradation of tetracycline hydrochloride by a novel CDs/g-C3N4/BiPO4 under visible-light irradiation: Reactivity and mechanism. Overall study is novel and contaminant is unique in photocatalysis. The whole manuscript is bad in language and have simple mistakes for example the word "pesudo". This is one example of careless attitude towards a good work. I recommend this publication to consider after reviewing from professional editing service.
Author Response
Dear reviewer
Thanks again for your efficient work in processing our manuscript entitled “Degradation of tetracycline hydrochloride by a novel CDs/g-C3N4/BiPO4 under visible-light irradiation: Reactivity and mechanism” (Manuscript ID: catalysts-1801665) and your valuable comments. We would also like to thank you for giving us the opportunity to revise our manuscript.We thank for you careful read and thoughtful comments on previous manuscript. We have carefully taken the comments into consideration in preparing our revision and believe that the additional changes we have made in response made this a significantly stronger manuscript.
The corresponding revision in the revised manuscript has been outlined in red front. Note file is our point-by-point response to the comments. Thanks again for your help. Look forwards your good news.
Sincerely yours,
Zeng-Hui Diao
School of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering
501 Zhongkai Road, Guangzhou, 510225, China
Tel: 86-20-89003188, Fax: 86-20-89003188
E-mail: zenghuid86@163.com.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Qian et al. investigated the CDs/g-C3N4/BiPO4 (CDBPC) composite for the removal of the antibiotic tetracycline hydrochloride (TC) in water. The composite is synthesized using the hydrothermal route and characterized using BET surface analysis, XRD, FTIR, SEM, and TEM. The effect of catalyst loading, pH, and concentration on the TC degradation is studied.
There are several mistakes in the text that the authors need to rectify. The authors' work can be considered for publication after addressing the following comments.
1) Nowhere in the manuscript it is provided what CDs stand for (except in keywords). The authors need to provide the full form in the initial part of the manuscript and later can start using the abbreviation.
2) Line 90-91: “Therefore, it was presumed that spherical crystals were CDs crystals, which was 90 consistent with the results of previous studies”
What about EDS (SEM/TEM) to detect the elemental composition?
3) Figure 3: Please use either CDs or CQDs in the legend and throughout the paper.
4) Line 121: “No impurity peaks were observed, confirming the high purity of the products.”
What about the peaks that are not marked in the region 26-32, 50-60, 65-80 degrees?
5) For Fig 4-8, the discussion uses the wrong figure numbers (lines 128, 143, 153, 178, 191, 204). For eg: in line 128, “the results are shown in Fig. 5. The peaks in the wavenumber range between 680 and 480”.
It should be Fig 4.
6) Fig 5: Again, there is inconsistency in the legend. Plot A uses CQDs whereas Plot B uses CDs.
7) Line 144-145: “Compared with BiPO4/g-C3N4, the absorption intensity of CDBPC 144 decreased, but its absorption range increased significantly”
Are the amounts of sample used for the UV analysis comparable? Do both the samples have a similar amount of C3N4/BiPO4?
8) Line 146: “band edge of CDBPC implied that the addition of g-C3N4 reduced the band gap of the.”
Shouldn't it be the CDs?
9) Fig 6: What about the control experiment using only C3N4/BiPO4? How different is the activity compared to 3wt% CDs/C3N4/BiPO4?
10) Fig 9: What is the contrast plot?
11) Line 280: “The jumped electrons 280 then combined with O2 to produce”.
The term “jumped” is not commonly utilized. It can be replaced with excited electrons or electrons in the CB
12) The experimental discussion needs to be improved. Need to provide what solvents are being used. How is the pH of the solution adjusted?
Author Response
Dear reviewer
Thanks again for your efficient work in processing our manuscript entitled “Degradation of tetracycline hydrochloride by a novel CDs/g-C3N4/BiPO4 under visible-light irradiation: Reactivity and mechanism” (Manuscript ID: catalysts-1801665) and your valuable comments. We would also like to thank you for giving us the opportunity to revise our manuscript.We thank for you careful read and thoughtful comments on previous manuscript. We have carefully taken the comments into consideration in preparing our revision and believe that the additional changes we have made in response made this a significantly stronger manuscript.
The corresponding revision in the revised manuscript has been outlined in red front. Below is our point-by-point response to the comments. Thanks again for your help. Look forwards your good news.
Author Response File: Author Response.pdf
Reviewer 3 Report
This paper reports the study a novel CDs/g-C3N4/BiPO4 (CDBPC) composite was successfully synthesized by a hydrothermal method for the removal of the antibiotic tetracycline hydrochloride (TC) in water. The experimental results showed that the synthesized photocatalyst was crystalline rods and cotton balls, accompanied by overlapping layered nanosheet structures, and the specific surface area was as high as 518.50 m2/g. This photocatalyst contains g-C3N4 and bismuth phosphate (BiPO4) phases, as well as abundant surface functional groups such as C=N, C-O and P-O. When the optimal conditions were pH 4, CDBPC dosage of 1 g/L, and TC concentration of 10 mg/L, the degradation rate of TC reached 75.50%. Active species capture experiments showed that the main active species in this photocatalytic system were holes (h+), hydroxyl radicals and superoxide anion radicals. The reaction mechanism for the removal of TC by CDBPC was also proposed. The removal of TC was mainly achieved by the synergy between the adsorption of CDBPC and the oxidation of both holes and hydroxyl radicals. In this system, TC was adsorbed on the surface of CDBPC, and then the adsorbed TC was degraded into small molecular products by attack with holes and hydroxyl radicals and finally mineralized into carbon dioxide and water. This study indicated that this novel photocatalyst CDBPC has a huge potential for antibiotic removal, which provides a new strategy for antibiotic treatment of wastewater. The experimental results are interesting and informative, but some data were not well presented. Details are listed below.
Comments for author File: Comments.pdf
Author Response
Dear reviewer
Thanks again for your efficient work in processing our manuscript entitled “Degradation of tetracycline hydrochloride by a novel CDs/g-C3N4/BiPO4 under visible-light irradiation: Reactivity and mechanism” (Manuscript ID: catalysts-1801665) and your valuable comments. We would also like to thank you for giving us the opportunity to revise our manuscript.We thank for you careful read and thoughtful comments on previous manuscript. We have carefully taken the comments into consideration in preparing our revision and believe that the additional changes we have made in response made this a significantly stronger manuscript. The corresponding revision in the revised manuscript has been outlined in red front. Below is our point-by-point response to the comments. Thanks again for your help. Look forwards your good news.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The manuscript can now be accepted in its current form.
Reviewer 3 Report
Good
