Application of BiVO₄–Microalgae Combined Treatment to Remove High Concentration Mixture of Sulfamethazine and Sulfadiazine

Round 1

Reviewer 1 Report

The Authors presented a study entitled: “Application of BiVO4-microalgae combined treatment to remove high concentration mixture of sulfamethazine and sulfadiazine”.

The work is very interesting.

The aim of the study and the obtained results are clearly highlighted.

However, the Authors should consider the following advice:

In the “Introduction”, the reference 54 reported at line 79 should be the 25; so, therefore, all the following references should be checked and corrected.

Please, check the word “references” reported at line 101; eventually, please, delete it or, otherwise, add a reference.

Please, in my opinion, a reference should be added at the end of the period reported at lines 99-100.

In the “Materials and Methods” section, please, check and correct the error typo “Figureures” reported at lines 191-192.

In my opinion, in the manuscript, the reference to figure S1 (reported in the “Supplementary section”) should be described.

In my opinion, in the “Supplementary section”, it should be better to modify the expression “In addition” reported at line 35; it seems to be redundant with the following part of the period.  

In my opinion, some more information about the experimental setup for performing photodegradation should be reported.

Moreover, as a suggestion, the adsorption process should be better characterized from kinetics and thermodinamics point of view.

Additionally, it should be helpful to assess how the phisico-chemical parameters such as pH, ionic strenght and temperature, could affect the adsorption process.

These parameters could also affect the recovery process of photocatalyst and the reuse efficiency (thus, the performance) of both the photocatalyst and microalgae.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

 

The work presented in this study is a continuation of the work carried out by some of the co-authors previously published by Chen et al.¹ In this study they present a follow-up comparison of removal of two Sulfonamides, namely sulfamethazine and sulfadiazine. The methods and experimental conditions are very close to the ones employed by Chen et al., this time focusing on the chemistry of the reactions by monitoring the production of •O₂^– and •OH radicals. The manuscript requires significant improvements in language and the justification of key statements with relevant experiments and additional data. I suggest its publication only after those revisions have been made.

 

Specific comments:

 

Abstract:

 

Some sentences in the abstract are not very clear. I suggest rewriting the abstract and cleary stating what is the focus of the article.

 

Introduction:

 

1. 57: References to other publications involving BiVO4 usage for environmental remediation are needed, including the articles published by some of the co-authors of this study.

 

1. 69: This sentence is very vague. The authors need to improve their description of the importance of BiVO4 synthesis.

 

1. 89: There is little explanation on the interest of combining the study of sulfamethazine and sulfadiazine removal. I feel that this could be clarified better in the introduction.

 

1. 96: I do not see any techno-economic analysis in this study. Therefore, this statement is not justified.

 

1. 99: Same comment as before regarding mechanistic studies. They are missing from this study.

 

Materials and methods:

 

1. 120: Details are missing regarding the illumination method used during the experiments.

 

Results:

 

1. 239: The production of •OH radical with Algae+BiVO4 do not seem to match the rates presented in Figure 5 of the study published by Chen et al. A comparison of those rates is needed to understand why there is a mismatch.

 

1. Chen, S.;Yuan, M.;  Feng, W.;  Liu, W.;  Zhang, W.;  Xu, H.;  Zheng, X.;  Shen, G.;  Guo, C.; Wang, L., Catalytic degradation mechanism of sulfamethazine via photosynergy of monoclinic BiVO4and microalgae under visible-light irradiation. Water Research 2020, 185, 116220.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The Authors have complied with most of the requested changes into the manuscript.

However, please, check the reference 43 in the manuscript which is missing.