β-Phosphonated Glycine Pendant Groups Grafted on Styrene-6.7% Divinylbenzene Copolymers: Synthesis and Their Application as Photocatalysts
Round 1
Reviewer 1 Report
1. In the introduction, the novelty of this draft should be emphasized.
2. The introduction part is not specific and thorough enough. It is suggested to summarize relevant literature on dye treatment by using different materials as photocatalyst.
3. What impact will this synthetic material have on biology or human beings after entering the environment?
4. With a catalyst concentration of 1 g/L and 240 minutes of irradiation, a photocatalysis efficiency of 98.6 % was obtained by using 25 mg/L initial concentration of Congo red dye. Is it economically reasonable to use so many catalysts and take so long to remove so few dyes?
5. How many times can this catalyst be used? This should be shown by experimental data.
6. At the end of the manuscript, future applications of this catalyst should be prospected.
Author Response
We are grateful to the reviewer for his valuable comments and for the time given to the review, which has been helpful in improving the quality of our work. The changes in the manuscript according to the reviewers suggestions were made in red.
Q1. In the introduction, the novelty of this draft should be emphasized.
Answer
The novelty of the study was emphasized in the introduction section.
Q2. The introduction part is not specific and thorough enough. It is suggested to summarize relevant literature on dye treatment by using different materials as photocatalyst.
Answer
The introduction part summarizes relevant literature on dye treatment, furthermore in table 3 are presented the photocatalytic performance of various materials developed in water treatment with dyes content, which underlined the performance of our new developed photocatalyst materials.
Q3. What impact will this synthetic material have on biology or human beings after entering the environment?
Answer
Global trends towards environmental protection imply the reconsideration of the possibility of using polymeric materials as supports with pendant active groups that could play an important role in environmental requirements. The polymer support used in this study is intensive used in the industrial production of ionic exchange resins. Additionally, it presents highly chemical and thermal stability, and after photocatalytic treatment of water with dye content it is easily recovered by filtration, reused in many cycles of treatment, and when it is exhausted could be proper discharged and its impact on biology and human beings is all most minimal.
Q4. With a catalyst concentration of 1 g/L and 240 minutes of irradiation, a photocatalysis efficiency of 98.6 % was obtained by using 25 mg/L initial concentration of Congo red dye. Is it economically reasonable to use so many catalysts and take so long to remove so few dyes?
Answer
To our knowledge, this is the first time that this type of photocatalysts were used in the study of water treatment. Knowing that for finishing treatments of water quality, the efforts are greater to remove low concentrations of pollutants, we consider that the results obtained in this study are encouraging. Table 3 presents the performance of various photocatalysts, mentioned in specialty literature, developed in the treatment process of water with CR content. It could be observed that our synthesized materials present a superior efficiency compared with more expensive and difficult to synthesized inorganic or organic nanoparticles and composites, which achieved a lower degradation efficiency, needing a much higher treatment time using a lower initial concentration of the CR in the solution.
Q5. How many times can this catalyst be used? This should be shown by experimental data.
Answer
Thank you for your suggestion. Experimental data regarding the efficiency of the studied photocatalyst in three treatment cycles were introduced in the manuscript. (See section 3.2.7) The photocatalytic materials presented a degradation efficiency > of 90% for 3 treatment cycles.
Q6. At the end of the manuscript, future applications of this catalyst should be prospected.
Answer
Featured applications are presented before abstract, according with the instruction for authors for this journal.
Reviewer 2 Report
The paper describes the synthesis and characterization of photocatalysts to decompose dye that is contaminating water. The topic is interesting and the paper is overall well presented. The reviewer would like to add a few comments hoping to help the paper improve.
· The abstract could have stated how this technique compares with the current method for battling water contamination from dyeing. Or if this is the first-ever case of decomposing dye in water via photocatalysis.
· In section 3.1, EDX was used as the sole method of element analysis, which is known to be error-prone for light elements such as carbon or nitrogen. Did the author have any other method to cross-exam the accuracy of the element analysis?
· Figure 6, it would be nice to see the error bars added to the graph to address the degree of repeatability of the test sets. Same as Figure 7 and 8.
Author Response
We are grateful to the reviewer for his valuable comments and for the time given to the review, which has been helpful in improving the quality of our work. The changes in the manuscript according to the reviewers suggestions were made in red.
The paper describes the synthesis and characterization of photocatalysts to decompose dye that is contaminating water. The topic is interesting and the paper is overall well presented. The reviewer would like to add a few comments hoping to help the paper improve.
Q1. The abstract could have stated how this technique compares with the current method for battling water contamination from dyeing. Or if this is the first-ever case of decomposing dye in water via photocatalysis.
Answer
Thank you for your suggestion. In the introduction we summarized the water treatment processes in the textile industry and presented the stages of the treatment process, emphasizing the tertiary stage, where one or more of the processes can be utilized: coagulation-flocculation, adsorption, membrane separation, oxidation, electrolysis. Then we showed the advantages of oxidation processes, among which is photocatalysis.
Q2. In section 3.1, EDX was used as the sole method of element analysis, which is known to be error-prone for light elements such as carbon or nitrogen. Did the author have any other method to cross-exam the accuracy of the element analysis?
Answer
Yes, it is correct the EDX is a semi quantitative analysis, but unfortunately, we don’t have access to any other method to cross-exam the accuracy of the element analysis.
Q3. Figure 6, it would be nice to see the error bars added to the graph to address the degree of repeatability of the test sets. Same as Figure 7 and 8.
Answer
The error bars were added to figures 6, 7 and 8.
Reviewer 3 Report
This paper deals with an interesting topic and can be interesting for readers of the journal. However, the manuscript lacks the novelty and originality that is necessary for publication. Many of such research have recently been published and I can't see any new significant highlights in the paper that hasn't been addressed already. Therefore, it will be difficult for this manuscript to be published in this journal.
Author Response
This paper deals with an interesting topic and can be interesting for readers of the journal. However, the manuscript lacks the novelty and originality that is necessary for publication. Many of such research have recently been published and I can't see any new significant highlights in the paper that hasn't been addressed already. Therefore, it will be difficult for this manuscript to be published in this journal.
Answer
The purpose of the present paper is the obtaining of novel photocatalysts that present β-phosphonated glycine pendant groups on the surface of the styrene-6.7%divinylbenzene copolymer and is tested for the first time their action as photocatalysts. The novelty and originality of the study was emphasized in the introduction and in the results and discussion sections. We improved our manuscript according with the reviewers comments and suggestions and we hope that in this format this accomplish the requirements of the journal in order to be accepted for publishing.
Round 2
Reviewer 1 Report
The revised draft can be accepted.
Reviewer 3 Report
