Insights into the Ligand Effect in β-CD@Fe₃O₄ Composites to Activate Peroxymonosulfate for Efficient Degradation of Pharmaceutical Contaminants: A Study Employing Density Functional Theory

Round 1

Reviewer 1 Report

Comments for Editor and Authors

In the present study the authors have evaluated the usage of β-cyclodextrin (β-CD) encapsulated iron oxide nanoparticles (β-CD@Fe3O4) composites, modified with different ligands (CIT, PEI, and CTAB), to activate PMS for the degradation of pharmaceutical contaminants (DCF, CBZ and ERY). They have employed the DFT calculations to examine the electronic structure and charge distributions of the β-CD@Fe3O4 composites, providing insights into their interaction with various pollutants. Although the current study identifies the role of surface chemistry in modulating the activation of PMS and degradation of pollutants and provides alternatives for designing tailored β-CD composites for environmental remediation, it has significant shortcomings. After the manuscript is revised by considering the comments given below, it is appropriate to publish it in the Coating journal.

1.       One of the most important shortcomings of the study is that the synthesized catalysts were not characterized. Synthesized catalysts should be characterized using different techniques such as SEM, FTIR, XRD, XPS, etc. and their structures should be interpreted.

2.       There are many experimental variables (such as pH, amount of catalyst, amount of PMS, time, temperature, etc.) that affect the degradation of organic pollutant species. Other important shortcomings of the study is that none of these parameters were optimized. Although the DFT calculations were made carefully and logically, the study is weak in terms of examining the experimental factors. The impact of important factors that may affect degradation should be examined.

3.       The degradation of which pollutant species is investigated should be stated in the Abstract.

4.       Has the degradation efficiency of β-CD@Fe3O4 composites been evaluated for pollutant species before modification with ligand?

5.       Why were citric acid, polyethyleneimine and cetyl trimethyl ammonium bromide chosen for modification? Which features of these were intended to be taken advantage of? Also, what are the effects of the pollutants (diclofenac, carbamazepine and erythromycin) to be degraded on the environment and human health? Are there tolerance limits for these pollutant species? These should be stated in the introduction section.

6.       The authors have cited references 16-18 for the Synthesis of β-CD@Fe3O4 linked with CIT, PEI, and CTAB. However in these references (in ref 16) only β-CD@Fe3O4 linked with PEI was given. It does not contain any information for other modifications. Moreover, even if a reference is cited to the synthesis procedure, the procedure should be briefly explained in the main text or in the supplementary materials.

7.       The reusability of catalysts should be examined.

8.       In page 3, in line 106-108 “As presented in Fig. 1, over 90% degradation efficiency for each pollutant was achieved via the β-CD@PEI@Fe3O4.....” However by using β-CD@PEI@Fe3O4, 90% degradation efficiency was obtained for only DCF. Please revise.

Author Response

Reply to Reviewer #1’s comments

1. One of the most important shortcomings of the study is that the synthesized catalysts were not characterized. Synthesized catalysts should be characterized using different techniques such as SEM, FTIR, XRD, XPS, etc. and their structures should be interpreted.

Reply:

Thank you for your valuable comments and suggestions regarding our manuscript. We understand the importance of characterizing synthesized catalysts to comprehensively present our research findings. However, the primary focus of our study is on the theoretical aspects, specifically the Density Functional Theory (DFT) calculations of the β-CD@Fe₃O₄ composites. These composites were synthesized according to methods well established and previously published in the literature (as cited in Section 2.2 of our manuscript). In our study, we have emphasized the electronic structure and charge distributions of the β-CD@Fe₃O₄ composites through DFT calculations, providing insights into their interaction with various pollutants. This theoretical approach is crucial to understanding the ligand effect and its influence on the degradation performance of these composites. As the synthesis and basic characterization of the β-CD@Fe₃O₄ composites have already been adequately addressed in previous studies, we focused on the advanced theoretical analysis, which is the novelty of our research. That said, we acknowledge the importance of characterizing synthesized materials in general and have referred readers to the pertinent literature where detailed characterizations of these materials have been conducted. This approach allows us to concentrate on the unique aspects of our study while ensuring that the synthesized materials are well-understood and validated by previous research.

2. There are many experimental variables (such as pH, amount of catalyst, amount of PMS, time, temperature, etc.) that affect the degradation of organic pollutant species. Other important shortcomings of the study is that none of these parameters were optimized. Although the DFT calculations were made carefully and logically, the study is weak in terms of examining the experimental factors. The impact of important factors that may affect degradation should be examined.

Reply:

Thank you for your insightful feedback and for highlighting the importance of experimental variables in the degradation of organic pollutants. We appreciate the opportunity to clarify the scope and focus of our study. Our research primarily revolves around the theoretical investigation of β-CD@Fe₃O₄ composites using Density Functional Theory (DFT) calculations. The aim is to gain a deeper understanding of the electronic structure and charge distributions of these composites and their interactions with pollutants. This theoretical focus is pivotal in elucidating the underlying mechanisms at a molecular level, which could potentially guide future experimental research. Regarding the experimental parameters such as pH, catalyst amount, amount of PMS, time, and temperature, we based our theoretical study on the experimental conditions that have been well-established and validated in previous literature. Our intention was to apply these established experimental frameworks as a reference point for our DFT calculations, rather than optimizing these parameters anew. This approach was chosen to ensure that our theoretical insights are grounded in realistic and proven experimental conditions, thus enhancing the applicability and relevance of our findings. We acknowledge that the experimental optimization of these variables is crucial and holds significant value in practical applications. However, the scope of our current study was deliberately narrowed to focus primarily on theoretical calculations. We believe this focus allows us to contribute detailed and specific insights into the molecular interactions and mechanisms, which can be a valuable foundation for future studies aiming to optimize experimental conditions. In light of this, we hope that our study is seen as a complementary piece to the broader research on β-CD@Fe₃O₄ composites, contributing theoretical insights that can inform and guide future experimental optimization.

3. The degradation of which pollutant species is investigated should be stated in the Abstract.

Reply:

Thanks for the suggestions. The degradation of pollutant species is added and highlighted in the Abstract.

Line 9-12: “This study presents a detailed investigation into the use of β-cyclodextrin (β-CD) encapsulated iron oxide nanoparticles (β-CD@Fe₃O₄) composites, modified with different ligands, to activate peroxymonosulfate (PMS) for the degradation of pharmaceutical contaminants, namely diclofenac, carbamazepine, and erythromycin.”

4. Has the degradation efficiency of β-CD@Fe3O4 composites been evaluated for pollutant species before modification with ligand?

Reply:

Thank you for your comment regarding the inclusion of degradation efficiency data for unmodified β-CD@Fe₃O₄ composites. I would like to clarify that the primary aim of our study was to investigate and compare the degradation efficiencies of β-CD@Fe₃O₄ composites when modified with different ligands, namely citric acid (CIT), polyethyleneimine (PEI), and cetyl trimethyl ammonium bromide (CTAB). The rationale behind this approach was to elucidate how different ligands impact the degradation capabilities of the composites against specific pharmaceutical pollutants (diclofenac, carbamazepine, and erythromycin). This comparison is central to our study as it highlights the significant role of surface chemistry modifications in enhancing the degradation process. While the degradation efficiency of the unmodified β-CD@Fe₃O₄ composites is an interesting aspect, it falls outside the scope of our current research focus. Our aim was to delve deeply into the comparative analysis of ligand-modified composites to understand how these modifications influence the overall degradation process. We appreciate your insights and understand that including data on the unmodified composites could provide a broader context. However, we believe that our current focus on ligand-modified composites offers a more targeted and detailed understanding of the degradation mechanisms in play, which aligns with the novel contributions of our research.

5. Why were citric acid, polyethyleneimine and cetyl trimethyl ammonium bromide chosen for modification? Which features of these were intended to be taken advantage of? Also, what are the effects of the pollutants (diclofenac, carbamazepine and erythromycin) to be degraded on the environment and human health? Are there tolerance limits for these pollutant species? These should be stated in the introduction section.

Reply:

Thank you for your insightful questions. We appreciate the opportunity to clarify the rationale behind our choices and to expand upon the environmental and health impacts of the studied pollutants. The ligands selected for modification of the β-CD@Fe₃O₄ composites, namely citric acid (CIT), polyethyleneimine (PEI), and cetyl trimethyl ammonium bromide (CTAB), were chosen due to their distinct chemical properties, which we hypothesized would differentially impact the degradation efficiency of the composites. CIT is known for its biodegradability and ability to introduce carboxyl groups, PEI for its dense array of amine groups that can enhance electrostatic interactions, and CTAB for its long alkyl chains that could facilitate hydrophobic interactions. The chosen pharmaceutical pollutants – diclofenac, carbamazepine, and erythromycin-are known for their persistence and potential adverse effects on aquatic ecosystems and human health. Their inclusion in this study is due to their widespread presence and the need to address their environmental impacts effectively. We will incorporate available information on the regulatory tolerance limits for these pollutants in our revised manuscript. Based on your suggestions, we will make the necessary amendments to the Introduction section to provide a more comprehensive context for our study.

Line 31-35：“It has been reported that diclofenac accumulates in various organs of fish at low concentrations (5 μg/L) [3]. Additionally, a mixture of pharmaceuticals including carbamazepine at ng/L levels has been shown to inhibit the growth of human embryonic cells [4]. The biologically active properties of macrolide antibiotics, such as erythromycin, render them highly toxic to aquatic organisms [5].”

Line 63-72：“The rationale behind selecting these three linking agents is based on their distinct functional properties and compatibility with β-CD. Citric acid, a tricarboxylic acid, offers multiple carboxyl groups that can chelate with iron oxide, enhancing the stability of the β-CD moiety on the nanoparticle surface. Polyethyleneimine provides a dense array of amine groups that can be protonated, thus introducing a positive charge to the nanoparticle surface which is advantageous for adsorbing negatively charged contaminants. Lastly, cetyl trimethyl ammonium bromide, a quaternary ammonium compound, presents hydrophobic tail groups that can interact with the hydrophobic cavity of β-CD, potentially increasing the hydrophobic interactions with nonpolar contaminants.”

Reference

[3] Veera Koskue, Juliette Monetti, Natascha Rossi, Ludwika Nieradzik, Stefano Freguia, Marika Kokko, Pablo Ledezma. Fate of pharmaceuticals and PFASs during the electrochemical generation of a nitrogen-rich nutrient product from real reject water. Journal of Environmental Chemical Engineering, 10 (2) (2022), 107284. https://doi.org/10.1016/j.jece.2022.107284

[4] Juan José Rueda-Márquez, Cassandra Palacios-Villarreal, Manuel Manzano, Eduardo Blanco, Mila Ramírez del Solar, Irina Levchuk. Photocatalytic degradation of pharmaceutically active compounds (PhACs) in urban wastewater treatment plants effluents under controlled and natural solar irradiation using immobilized TiO₂. Solar Energy, 208 (2020), 480-492. https://doi.org/10.1016/j.solener.2020.08.028

[5] Marta Sendra, Alejandro Damián-Serrano, Cristiano V.M. Araújo, Ignacio Moreno-Garrido, & Julián Blasco. Erythromycin sensitivity across different taxa of marine phytoplankton. A novel approach to sensitivity of microalgae and the evolutionary history of the 23S gene. Aquatic Toxicology, 204 (2018), 190-196. https://doi.org/10.1016/j.aquatox.2018.09.008

6. The authors have cited references 16-18 for the Synthesis of β-CD@Fe3O4 linked with CIT, PEI, and CTAB. However in these references (in ref 16) only β-CD@Fe3O4 linked with PEI was given. It does not contain any information for other modifications. Moreover, even if a reference is cited to the synthesis procedure, the procedure should be briefly explained in the main text or in the supplementary materials.

Reply:

Thanks for your suggestions. The synthesis procedure is added in the supplementary materials.

Line 73-75: “A detailed description of the synthesis protocols employed for the preparation of β-CD@Fe₃O₄ composites can be found in the Supplementary Information (Text S1).”

“Text S1. The synthesis procedure of β-CD@Fe₃O₄ linked with CIT, PEI, and CTAB

(1) Synthesis of Fe₃O₄@PEI@β-CD:

Firstly, Fe₃O₄@PEI is synthesized through a hydrothermal coating method. To achieve this, 2 g of FeCl₃·6H₂O is dissolved in 65 mL of ethylene glycol, followed by the addition of 6 g of anhydrous sodium acetate and 3 g of polyethyleneimine (PEI). After stirring for 30 minutes, the mixture is transferred to a polytetrafluoroethylene-lined autoclave and reacted at 200°C for 6 hours. Upon cooling to room temperature, the product is washed with anhydrous ethanol and dried, resulting in Fe₃O₄@PEI, which is then freeze-dried. Subsequently, the synthesized Fe₃O₄@PEI is functionalized with carboxymethylated β-CD to form Fe₃O₄@PEI@β-CD: 6 g of β-CD and 13 g of maleic anhydride are dissolved in 100 mL of anhydrous DMF. The solution is stirred under nitrogen for 48 hours. Then, 100 mL of ethyl acetate is added, followed by uniform stirring and filtration to yield a viscous white substance. After washing and drying, carboxymethylated β-CD is obtained. A solution containing 0.86 g of carboxymethylated β-CD, 0.1 g of DMAP, and 1.12 g of EDC in 100 mL of deionized water is stirred for 2 hours. Then, 2 g of Fe₃O₄@PEI is added and subjected to ultrasonic treatment for 20 minutes to ensure uniform dispersion of the particles. After stirring for 48 hours, the particles are separated using a magnet. Finally, Fe₃O₄@PEI@β-CD is washed and freeze-dried for further use.

(2) Synthesis of Fe₃O₄@CIT@β-CD:

Synthesis of Fe₃O₄: Magnetite nanoparticles (MNPs) were prepared using the co-precipitation method. Briefly, 2 mmol of FeCl₃·6H₂O (0.54 g) and 1 mmol of FeCl₂·4H₂O (0.198 g) were added to 20 ml of deionized water in a 250 ml round-bottom flask. The mixture was ultrasonicated for 20 minutes at room temperature. The temperature was gradually raised to 60°C, and then 1 M NaOH solution was added dropwise under N₂ atmosphere until the pH of the solution reached 10-11. The mixture was further ultrasonicated for 30 minutes, followed by magnetic separation and washing with deionized water.

Synthesis of CD-CIT: The CD-CIT complex was prepared via an esterification reaction between the -COOH group of citric acid and the primary -OH group of CD, following a previously reported procedure. Citric acid (1 g) and β-CD (3 g) were dissolved in 10 ml of water and stirred at 80°C for 3 hours. The solution became clear and was then treated with isopropanol (15 ml) to precipitate a white solid. The mixture was filtered and thoroughly washed 2-3 times with water (3 × 10 ml) to remove unreacted components, and then dried at 60°C for 24 hours in a hot air oven to prepare the white solid CD-CIT complex.

Synthesis of Fe₃O₄@CIT@β-CD: Fe₃O₄ (0.27g) was redispersed in 100 ml of distilled water, and a CD-CIT complex aqueous solution (10 mL, 0.97 g CD-CIT) was added dropwise. The mixture was stirred at 80°C for 4 hours, yielding a black dispersion of the desired nanocatalyst, which was then separated with an external magnet and thoroughly washed with deionized water (10 ml × 3). The product was dried at 70°C for 24 hours in a forced-air drying oven to obtain the desired magnetic nano-phase transfer catalyst.

(3) Synthesis of Fe₃O₄@CTAB@β-CD:

Iron oxide nanoparticles were synthesized using the co-precipitation method. In a typical synthesis, FeCl₃·6H₂O (21.62 mg) and FeSO₄·7H₂O (11.12 mg) were dissolved in 40 mL of deionized water in a 2:1 ratio. During the reaction process, the solution mixture was heated to 50°C under constant stirring. After 10 minutes, a specified amount of CTAB (7.29 mg) and β-CD (22.7 mg) were added, maintaining a ratio of FeSO₄·7H₂O to CTAB to β-CD at 1:0.5:0.5. After stirring with CTAB for 30 minutes, an ammonia solution (25% NH₄OH) was added dropwise to precipitate iron oxide nanoparticles. The final precipitate was thoroughly washed several times with deionized water to remove excess reagents and then freeze-dried.”

7. The reusability of catalysts should be examined.

Reply:

Thank you for your valuable suggestion regarding the examination of the reusability of the catalysts used in our study. We fully agree that the reusability of catalysts is a crucial aspect in the practical application of catalytic processes, particularly for environmental and economic sustainability. In the current scope of our study, our primary focus was on the synthesis and initial efficiency evaluation of the β-CD@Fe₃O₄ composites modified with various ligands. Due to this focused scope and the extensive depth of analysis required for reusability studies, such evaluations were not included in this submission. However, we recognize the significance of your suggestion and believe that the reusability of these catalysts is an important parameter that warrants thorough investigation. We are considering conducting a detailed study on this aspect in our future research. This would not only enhance the practical applicability of our findings but also contribute valuable insights into the long-term stability and efficiency of these modified composites. We appreciate your constructive feedback and are committed to exploring this avenue in our subsequent work, potentially leading to a follow-up publication that focuses specifically on the reusability and long-term stability of these novel catalysts. Thank you once again for your insightful comment, which certainly helps in improving the quality and applicability of our research.

8. In page 3, in line 106-108 “As presented in Fig. 1, over 90% degradation efficiency for each pollutant was achieved via the β-CD@PEI@Fe3O4.....” However by using β-CD@PEI@Fe3O4, 90% degradation efficiency was obtained for only DCF. Please revise.

Reply:

Thank you for your attentive reading and valuable observation regarding the degradation efficiency reported on page 3, lines 106-108 of our manuscript. The corresponding error has been revised in the manuscript.

Line 108-109: “over 90% degradation efficiency for DCF was achieved via the β-CD@PEI@Fe₃O₄ composite”

Reviewer 2 Report

From my point of view, this is an exciting work. The authors have performed a complete experimental, discussion and conclusion of the work. After some revisions, the paper can be accepted by the journal (the reviewer is willing to review the revised version of this paper), as follows:

1)The introduction should benefit from some lines on the role of new composite and their importance on environmental applications, e.g. outperforming adsorption capacity, effective degradation of compounds, and specificity in separating target molecules. Have a look and cite accordingly:

-Zeolitic imidazolate framework (ZIF-8) modified cellulose acetate NF membranes for potential water treatment application

-MXene-based materials for removal of antibiotics and heavy metals from wastewater–a review

3) the degradation results should be compared with the current literature in the field.

4) Interesting results and discussion; however, any insights on the hydrothermal stability of the composite inorganic material? it would be nice to give some information in the revised paper.

5) Please give feedback on the potentiality for other applications, e.g. depending on its size, it could be embedded in membranes for water treatment.

6) what is next in this research? please state the future perspectives of this work.

Author Response

Reply to Reviewer #2’s comments

1. The introduction should benefit from some lines on the role of new composite and their importance on environmental applications, e.g. outperforming adsorption capacity, effective degradation of compounds, and specificity in separating target molecules. Have a look and cite accordingly:

-Zeolitic imidazolate framework (ZIF-8) modified cellulose acetate NF membranes for potential water treatment application

-MXene-based materials for removal of antibiotics and heavy metals from wastewater–a review

 Reply:

Thank you for your valuable suggestion to enhance the Introduction section of our manuscript by discussing the role and importance of our composite material in environmental applications. We agree that emphasizing aspects such as the adsorption capacity, effective degradation of compounds, and specificity in separating target molecules would provide a more comprehensive context for our study. In light of your feedback, we will revise the Introduction to include these points. We will also consider the references you have suggested, namely the works on "Zeolitic imidazolate framework (ZIF-8) modified cellulose acetate NF membranes for potential water treatment application" and "MXene-based materials for removal of antibiotics and heavy metals from wastewater--a review," to provide a broader perspective on the relevance and impact of new composite materials in environmental remediation. We appreciate your guidance in making our manuscript more informative and relevant to the field.

Line 52-56：“Considering the remarkable physicochemical properties of many nanocomposite materials that have shown significant potential in water purification [9], along with the techniques involved in surface modification [10], a solution to this issue is the encapsulation of Fe₃O₄ nanoparticles with β-cyclodextrin (β-CD). This encapsulation results in the formation of a β-CD@Fe₃O₄ nanocomposite, which enhances its activation efficiency [11].”

Reference

[9] Farooque Ahmed Janjhi, Ihsanullah Ihsanullah, Muhammad Bilal, Roberto Castro-Muñoz, Grzegorz Boczkaj, Fausto Gallucci. MXene-based materials for removal of antibiotics and heavy metals from wastewater-a review. Water Resources and Industry, 29 (2023), 100202. https://doi.org/10.1016/j.wri.2023.100202

[10] Vahid Vatanpour, Ayse Yukselkadag, Meltem Ağtaş, Mohammad Mehrabi, Ehsan Salehi, Roberto Castro-Muñoz, Ismail Koyuncu. Zeolitic imidazolate framework (ZIF-8) modified cellulose acetate NF membranes for potential water treatment application. Carbohydrate Polymers, 299 (2023), 120230. https://doi.org/10.1016/j.carbpol.2022.120230

3) the degradation results should be compared with the current literature in the field.

Reply:

Thank you for your valuable feedback regarding the comparison of our degradation results with the current literature. I appreciate the importance of situating one's research within the existing body of knowledge. However, the primary objective of our study was not to compete with the degradation efficiencies reported elsewhere, but rather to deepen the understanding of the ligand effect on the activation of peroxymonosulfate (PMS) for the degradation of pharmaceutical contaminants. Our research provides a novel theoretical investigation into the electronic and charge distribution characteristics of β-CD@Fe₃O₄ composites modified with different ligands, which has not been extensively explored in the literature. The intention was to elucidate the underlying principles governing the interactions between these composites and various pollutants, which could then inform the design of more effective degradation systems. The theoretical nature of our work distinguishes it from many empirical studies that focus on degradation efficiencies under various conditions. While empirical studies often seek to optimize degradation conditions for maximum efficiency, our work is aimed at providing a foundational understanding that will support such optimization in future studies.

4) Interesting results and discussion; however, any insights on the hydrothermal stability of the composite inorganic material? it would be nice to give some information in the revised paper.

Reply:

Thank you for your encouraging comments on our results and discussion, and for raising the important point regarding the hydrothermal stability of the composite inorganic material. We agree that insights into the hydrothermal stability of these composites would be valuable for understanding their potential applications and durability under various environmental conditions. This aspect indeed represents a crucial parameter for evaluating the practical applicability of such materials. However, we regret to inform you that at the current stage of our research, we have not conducted studies focused on the hydrothermal stability of these composites. Our initial research efforts were primarily dedicated to synthesizing the composites and evaluating their degradation efficiency for specific pollutants. Due to the limited scope of our current project and resources, investigations into their hydrothermal stability were not included. That being said, we recognize the significance of your suggestion and believe that it presents an important direction for future research. We are keen to explore this aspect in subsequent studies and hope to report these findings in future publications. We appreciate your valuable feedback and will make a note in the revised paper to indicate that the hydrothermal stability of the composites, while crucial, falls outside the scope of the present study and is a promising area for future investigation. Thank you once again for your constructive comments, which help in shaping the direction of our ongoing research.

5) Please give feedback on the potentiality for other applications, e.g. depending on its size, it could be embedded in membranes for water treatment.

 Reply:

Thanks for your insightful suggestion regarding the exploration of broader applications for our synthesized β-CD@Fe₃O₄ composites, such as their potential integration into membrane technology for water treatment. We appreciate the significance of such applications and agree that they represent an important aspect of research in this field. However, the primary focus of our current manuscript is on the synthesis and initial efficiency evaluation of the composites with specific ligands for the degradation of certain pharmaceutical pollutants. We aimed to provide a detailed and thorough investigation within this specific scope. That said, we are excited to inform you that we are addressing the broader applications, including the incorporation of these composites into membranes for water treatment, in another study which is currently under review and will be published soon. This upcoming publication delves into these aspects in detail, and we believe it will significantly contribute to the field by exploring these additional applications. We hope that this forthcoming paper will offer the comprehensive insights you are interested in, and we invite you to follow our subsequent publications for a broader understanding of the potential applications of these composites. Thank you once again for your valuable input, which indeed helps in broadening the scope and impact of our research work.

6) what is next in this research? please state the future perspectives of this work.

 Reply:

Thank you for your inquiry regarding the future perspectives stemming from our current research. Our study has laid a solid foundation for several promising directions, which we aim to explore in our subsequent work. Building upon our findings on the degradation efficiency of β-CD@Fe₃O₄ composites with various ligands, future research could delve into:

Exploring additional ligand modifications: We plan to investigate the impact of other ligand types on the degradation efficiency of β-CD@Fe₃O₄ composites. This can provide a broader understanding of the ligand effect and potentially uncover more effective combinations for pollutant degradation.

Application in real-world scenarios: We aim to test the practical applicability of these composites in real-world water treatment scenarios, including large-scale applications and integration into existing wastewater treatment technologies.

Long-term stability and reusability studies: Further research will focus on the long-term stability and reusability of these composites, an important aspect for their practical application and environmental sustainability.

Broader spectrum of pollutants: Expanding the range of pollutants tested with these composites will help us understand their versatility and applicability to a wider array of environmental contaminants.

Advanced characterization techniques: Employing advanced characterization techniques to further investigate the surface chemistry and structure of these composites will aid in optimizing their design for specific applications.

These future research directions will help us deepen our understanding of the interactions between β-CD composites and pollutants and contribute to the development of more efficient materials for environmental remediation and wastewater treatment. Thank you once again for your interest in our work and for prompting a thoughtful consideration of its future implications.