Effect of Cucurbit[7]uril on Adsorption of Aniline Derivatives at Quartz
Round 1
Reviewer 1 Report
Comments
Authors have presented an article on “Effect of cucurbit[7]uril on adsorption of aniline derivatives at quartz” The manuscript in the current state can be accepted for publication after major revision mentioned below:
1. The written content has many mistakes and grammatical errors which need to be corrected.
2. The authors have used the term 'UV-Vis spectrometry', which is wrong.
3. The authors have suggested that the benzene ring of MDA gets trapped in the cage of Q7. It would be good if they could provide a plausible pictorial depiction of the same.
4. The authors have not specified the solvent media used for UV-Vis analysis.
5. The authors can also use fluorescence spectroscopy for analyzing the interaction of Q7 with AN and MDA.
6. The aspect that apart from being pollutants, the aniline derivatives have also been reported in the literature as recognition agents for heavy metal ions pollutants e.g. https://doi.org/10.1016/j.tetlet.2014.03.043, https://doi.org/10.1002/asia.201500956 should also be considered and incorporated in the manuscript.
After these modifications and re-review the article may be accepted.
Author Response
please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Coatings
Effect of cucurbit[7]uril on adsorption of aniline derivatives at quartz
Manuscript Number: coatings-1816654
This study focuses on studying the host-guest interaction of Q[7] with MDA and AN. Also, the influence of Q[7] on the adsorption behavior of MDA and AN on quartz surface were appraised.
The topic is so interested and the authors were made intensive efforts to write their paper that presented good results and a thorough discussion.
Please revise the paper within the following points before passing the paper to the production stream based on MINOR corrections
1. Abstract; at the beginning, please write a hock sentence to define the field of your study and its importance. Something like the first sentence of Introduction
2. Abstract: please use the present tense in the Abstract. Check the whole Abstract
3. Introduction: the authors have not included the most important results of the previous studies presented in the Introduction
4. Conclusions: please include the main aim of this study in the Conclusions
5. Please revise the whole manuscript for strengthening the languages. Some typos
Author Response
We thank the reviewer for the suggestions and have made the following reply to the suggestions for revision.
Comments 1: Abstract; at the beginning, please write a hock sentence to define the field of your study and its importance. Something like the first sentence of Introduction
Response: In the abstract, “the aniline derivatives are one of The main pollutants at present. The adsorption and desorption of them on a solid surface are an important scientific problem. "are modified to" adsorption behavior of small molecules at solid-liquid interface is an important research topic in recent years. For example, small molecules of aniline pollutants will adsorb on the solid surface with the massive discharge of industrial wastewater and are difficult to separate. Therefore, Their adsorption and desorption on solid surfaces have become an important scientific problem."
Comments 2: Abstract: please use the present tense in the Abstract. Check the whole Abstract
Response: The tenses of the entire abstract have been changed to the present tense. “The adsorption behavior of small molecules at solid–liquid interfaces have become an important research topic in recent years. For example, small molecules of aniline pollutants will adsorb on solid surfaces with a massive discharge of industrial wastewater and are difficult to separate. Therefore, their adsorption and desorption on solid surfaces have become an important scientific problem. In this study, The aniline derivatives are one of the main pollutants at present, the adsorption and desorption of them on a solid surface are an important scientific problem. the interactions of cucurbit[7]uril (Q[7]) with 4,4’-diaminodiphenylmethane (MDA) and benzidine (AN) were are studied using 1H NMR and , UV-Vis spectrometry and fluorescence spectroscopy .UV-vis absorption spectroscopy. The results showed that Q[7] formed forms an inclusion complex with MDA and AN. According to the results of Quartz Crystal Microbalance with Dissipation (QCM-D), MDA adsorbed adsorbs onto a quartz surface and formed forms a viscous adsorption layer on it. The AN adsorbed adsorbs on the quartz surface and formed forms a rigid adsorption film on it. Q[7] could can reduce the adsorption of MDA on the quartz surface, and increased increases the adsorption of AN on it. Through the dynamic adsorption experiments, it waswe found find that Q[7] had has a desorption effect on MDA molecules adsorbed on the quartz surface. An Atomic Force Microscope (AFM) was is used to measure the morphological changes in the adsorption film before and after Q[7] made make contact with the quartz surface, and it proved proves that Q[7] has a desorption effect on MDA molecules adsorbed on the surface.“
Comments 3: Introduction: the authors have not included the most important results of the previous studies presented in the Introduction
Response: In the introduction section, we add the latest research results published by our research group “Our team recently studied the interaction of quaternary ammonium cationic surfactant HD with Q[7] and AM. We concluded that Q[7] had host-guest interaction with HD, which reduced the surface activity of HD. After the addition of AM, the HD molecules were extruded from the Q[7] cavity by strong binding with Q[7], and HD restored its original surface activity. We also measured the effect of Q[7] on the adsorption behavior of HD on the quartz surface by QCM-D, and characterized the change of the surface morphology of the adsorption film before and after the introduction of Q[7] by AFM, we concluded that Q[7] can regulate the adsorption and desorption of HD molecules on the quartz surface”
Comments 4: Conclusions: please include the main aim of this study in the Conclusions
Response: We added the purpose of this study in the conclusion "In this paper, we used Q[7] to desorbed the MDA molecule on the Quartz surface, and determined the host-guest interaction mode between Q[7] with MDA and AN by UV-Vis, Fluorescence spectrometry and nuclear magnetic titration."
Comments 5: Please revise the whole manuscript for strengthening the languages. Some typos
Response: we submitted the manuscript to the MDPI team for polishing and revision
Reviewer 3 Report
The manuscript entitled “Effect of cucurbit[7]uril on adsorption of aniline derivatives at quartz” concerns the study of the interaction of cucurbit[7]uril with 4,4’-diaminodiphenylmethane and benzidine using 1H NMR and UV-Vis absorption spectroscopy. Moreover, the Authors conducted the study of the adsorption of benzidine and the mixture of benzidine and cucurbit[7]uril on quartz using the quartz crystal microbalance with dissipation monitoring. The Authors also measured the morphological changes of the adsorption film before and after the introduction of cucurbit[7]uril onto the quartz surface using an atomic force microscope.
The manuscript is correctly organized. The title reflects the article’s content. The results are presented in a comprehensible way. The figures show essential data. In my opinion, the research presented in the manuscript could be of interest to readers of the Coatings, however, there are several points that must be improved before publication.
- The Introduction section was described too briefly. Please, improve the Introduction (e.g. add more information about the research on the host-guest interactions between cucurbit[n]urils and different small molecules).
- The reason for undertaking the research presented in the manuscript is described too briefly. Please describe in detail the reason for undertaking the research on the effect of cucurbit[7]uril on adsorption of aniline derivatives on quartz as well as the importance of obtained results.
- The Authors carried out studies using cucurbit[7]uril. Why did the Authors choose cucurbit[7]uril for the study and not test other cucurbit[n]urils?
- In the References section, the article title is written in a non-uniform way (sometimes all words start with a capital letter, and sometimes only the first word is capitalized). Please unify the way of writing the title of the article.
- The manuscript contains linguistic and editing errors (e.g. there is a sentence without a full stop at the end of the sentence, in the References section, there is no subscript in the chemical formula of Fe3O4). Please read the article carefully and correct any mistakes.
Overall, the manuscript presents quite interesting results but needs to be improved before publication.
Author Response
We thank the reviewer for the suggestions and have made the following reply to the suggestions for revision.
Comments 1: The Introduction section was described too briefly. Please, improve the Introduction (e.g. add more information about the research on the host-guest interactions between cucurbit[n]urils and different small molecules).
Response: In the introduction, we added more information about the research on the host-guest interactions between cucurbit[n]urils and different small molecules:
“Suma et al. studied the host-object interaction between N-phenyl-2-Naphthylammonium ammonium (PH-AH-NP) and Q[7], and explored the influence of Na+ on the host-guest bonding mode of Ph-AH-Np@Q[7]. It was found that under the condition of low concentration of Na+, The action ratio of PH-AH-NP with Q[7] was 1:1 and there was only one action mode. Under the condition of high concentration of Na+, the action ratio of PH-AH-NP with Q[7] was 1:1 or 2:1, and there were three different action modes[24]. Ivanov et al. studied the host-guest interaction mode of 4-[(E)-2-(3,4-dimethoxyphenyl)ethenyl]-1-ethylpyridinium perchlorate(styryl dye) with Q[7] were studied. The results showed that styryl dye formed a 1:1 inclusion complex with Q[7][25]. (association constant K = 1.0 × 10 6 M−1 in the range of CB[7] concentration up to 16 μM)”
Comments 2: The reason for undertaking the research presented in the manuscript is described too briefly. Please describe in detail the reason for undertaking the research on the effect of cucurbit[7]uril on adsorption of aniline derivatives on quartz as well as the importance of obtained results.
Response: In the abstract section, we describe the reasons for this research, and in the conclusion section, we summarize the research results and explain and forecast the significance of this research result:
Abstract: The adsorption behavior of small molecules at solid–liquid interfaces have become an important research topic in recent years. For example, small molecules of aniline pollutants will adsorb on solid surfaces with a massive discharge of industrial wastewater and are difficult to separate. Therefore, their adsorption and desorption on solid surfaces have become an important scientific problem. In this study, the interactions of cucurbit[7]uril (Q[7]) with 4,4’-diaminodiphenylmethane (MDA) and benzidine (AN) are studied using 1H NMR, UV-Vis spectrometry and fluorescence spectroscopy .. The results showthat Q[7] forms an inclusion complex with MDA and AN. According to the results of Quartz Crystal Microbalance with Dissipation (QCM-D), MDA adsorbs onto a quartz surface and forms a viscous adsorption layer on it. The AN adsorbs on the quartz surface and forms a rigid adsorption film on it. Q[7] can reduce the adsorption of MDA on the quartz surface, and increases the adsorption of AN on it. Through the dynamic adsorption experiments, we find that Q[7] has a desorption effect on MDA molecules adsorbed on the quartz surface. An Atomic Force Microscope (AFM) is used to measure the morphological changes in the adsorption film before and after Q[7] make contact with the quartz surface, and it proves that Q[7] has a desorption effect on MDA molecules adsorbed on the surface.
Conclusion: In this paper, we used Q[7] to desorbed the MDA molecule adsorbed on the quartz surface, and determined the host-guest interaction mode between Q[7] and MDA and AN by UV-Vis, fluorescence spectroscopy and nuclear magnetic titration. The results showed that Q[7] could interact with MDA, AN to form the host-guest complex. The experimental results of QCM-D showed that MDA could adsorb on the surface of quartz and form the viscoelastic film. The AN could adsorb on quartz to form a rigid membrane. The host-guest interaction between Q[7] and aniline derivatives enhanced the adsorption of AN on quartz surface while reduced the adsorption of the MDA on quartz surface. MDA adsorbed on the surface of quartz could interact with Q[7], and it could desorb on the surface of the quartz. The adsorption of MDA decreased, and the viscoelasticity of the adsorption film decreased. Thus, Q[7] reversibly regulated the adsorption and desorption process of MDA on quartz surface. This experimental results also provided a possible research direction for people to study the removal of aniline derivatives adsorbed on solid surface in natural environment.
Comments 3: The Authors carried out studies using cucurbit[7]uril. Why did the Authors choose cucurbit[7]uril for the study and not test other cucurbit[n]urils?
Response: For Q[5], the cavity size is small, and the solubility of Q[6] and Q[8] in aqueous solution is too low. Therefore, we choose Q[7], which has relatively moderate cavity size and relatively high solubility in aqueous solution.
Comments 4: In the References section, the article title is written in a non-uniform way (sometimes all words start with a capital letter, and sometimes only the first word is capitalized). Please unify the way of writing the title of the article.
Response: In the reference section, we unified the format of the title of the article and changed the format of the reference to capitalize the first letter of the word
Comments 5: The manuscript contains linguistic and editing errors (e.g. there is a sentence without a full stop at the end of the sentence, in the References section, there is no subscript in the chemical formula of Fe3O4). Please read the article carefully and correct any mistakes.
Response: we submitted the manuscript to the MDPI team for polishing and revision
Reviewer 4 Report
This manuscript is lacking many scientific aspects for such widely investigated topic. Authors must signifivantly improve tjis manuscriot:
1) There is a lack od surfsce snalyses
2) There are many mistskes in hypotheses. E.g. the absorbace of the matetial by the quartz crystal on the qcm itself makes no sense because the qcm measures the chsnges if the mass if tge material on the electrode durface!!! Hence the surface is covered by gold! THE BARE QUARTZ SURFACE DOES NIT PLAY ANY ROLE IN THE QCM OPERATION!!!
3) TO MANY SIMPLE WELL KNOWN INFORMATION. E g. The explanation of qcm
4) Too many grammar mistakes and language needs improvements.
Author Response
We thank the reviewer for the suggestions and have made the following reply to the suggestions for revision.
Comments 1: There is a lack od surfsce snalyses
Response: This is a nice suggestion for the interpretation of the data. The surface analysis of similar studies has been detailed in another paper(doi:https://doi.org/10.1016/j.colsurfa.2021.126880.) The surface analysis of AN and MDA will be studied in detail in the next paper, which is also the direction we want to further explore at present. The main research direction of this paper is the host-guest interaction mode between aromatic amine small molecules and Q[7] and its influence on the adsorption behavior of small molecules at solid-liquid interface.
Comments 2: There are many mistskes in hypotheses. E.g. the absorbace of the matetial by the quartz crystal on the qcm itself makes no sense because the qcm measures the chsnges if the mass if tge material on the electrode durface!!! Hence the surface is covered by gold! THE BARE QUARTZ SURFACE DOES NIT PLAY ANY ROLE IN THE QCM OPERATION!!!
Response: The chip we use is silica-coated chip, customized by Sweden Bolin Scientific Company, and the chip is modified by silicon dioxide into homogeneous film material. In this paper, as the main component of quartz is silicon dioxide, we use silicon dioxide coating to replace the surface of quartz ore. We have modified all the descriptions of “quartz chips” in this paper to “Silica-coated chips” and explained them in the experimental.
In fact, there have been many reports of QCM-D studies using such chips, For example, Wang et al studied the interaction between Antimicrobial peptides (AMPs) and the bilayer of supported lipid bilayers (SLB) adsorbed on silica-coated chip surface by QCM-D(https://doi.org/10.1021/jp209658y). The study on the deposition kinetics of Organic Macromolecules (or foulants) on the surface of silicon dioxide using QCM-D has also been published recently, and the chips used are also silicon dioxide chips(https://doi.org/10.1021/acsestwater.1c00120)
Comments 3: TO MANY SIMPLE WELL KNOWN INFORMATION. E g. The explanation of qcm
Response: We have simplified the introduction of QCM-D, keeping only the experimental operation part and some necessary formulas.
We use sensor crystals coated with silica to simulate the surface of quartz ore The mass of the adsorbed molecules is determined by measuring the frequency shift of silica-coated chip
The frequency shift (ΔF) and energy dissipation (ΔD) can be measured simultaneously, and the decay of the quartz oscillation can be monitored in a real-time. Energy dissipation is the energy loss of a system. ΔD shows the viscoelastic properties of the adsorption layer of a solid surface. The Sauerbrey equation is used to determine the adsorbed in the silica-coated chips
where Δm is the adsorbed mass, C is the sensitivity constant, n is the overtone number (n = 1, 3, 5, 7, ...), and ΔF is the frequency shift.
Before we started the experiments of QCM-D, the sensor was cleaned completely, and dried by blowing it with N2. The flow rate of the aqueous solution was 100 μL/min. The data of the third overtone were used to analyze the adsorption of molecules onto the quartz.
The adsorption of the benzidine or the mixture of the benzidine and Q[7] on the quartz was monitored by QCM-D. First, water was pumped into the sample tank to eliminate the influence of water molecules in the solution to be tested, and then the aqueous solution of the benzidine was pumped into the chamber of QCM-D. The ΔF and ΔD values changed with the change in adsorption time until equilibrium.
The desorption of MDA at the quartz surface could be monitored in real-time by QCM-D. First, a similar method was used to study the adsorption of MDA on the quartz, and second, the injection of the solution of MDA was stopped when ΔF and ΔD remained unchanged, and then the aqueous solution of Q[7] was pumped into the sample chamber. The values of ΔF and ΔD varied over time until they reached equilibrium.
Comments 4: Too many grammar mistakes and language needs improvements.
Response: we submitted the manuscript to the MDPI team for polishing and revision
Round 2
Reviewer 1 Report
The authors have carried out the said modifications and thus the manuscript can be accepted.
Author Response
Thank you very much for your affirmation of my research, I will continue to work hard to provide more research results.
Reviewer 3 Report
The manuscript has been revised, and the changes and corrections made by the Authors are acceptable. The explanations provided by the Authors are satisfacroty.
Author Response
Thank you very much for your understanding and support, your suggestions are very important for my future research.
Reviewer 4 Report
The authors have made significant improvements and answered to the most important questions and clarified the details.
Please note that the formatting of your manuscript is not fall into the requirement of MDPI Coatings. After bringing it to the required format it can be accepted.
Author Response
Thank you very much for your suggestion, we have modified the manuscript format to MDPI format
