# Enhanced Performance of nZVI/MXene@CNTs for Rapid As(III) Removal from Aqueous Solutions
## 4 Conclusions  
In this study, a three-dimensional intercalation Ti\({}_{3}\)C\({}_{2}\)T\({}_{x}\) MXene carbon nanotube supported by nZVI nanocomplex (nZVI/MXene@CNTs) was properly prepared and employed for the rapid adsorption and catalytic oxidation of As(III) in aqueous solution. As a result, the mild method of liquid-phase reduction improved the stability, reactivity and magnetic recovery. The maximum adsorption of nZVI/MXene@CNTs was determined to be 443.32 mg/g in the As(III)-containing solutions with the conditions of pH = 3.0 and 25 \({}^{\circ}\)C. The As(III) oxidation process was likely significantly aided by the \(\bullet\)OH that nZVI generated when the nZVI/MXene@CNTs were present, which was obvious under acidic circumstances. The FTIR and XPS analyses and the adsorption model fitting results revealed that the removal of As(III) involved not only surface complexation, but also solid phase precipitation and the oxidation of the \(\bullet\)OH. Furthermore, the nZVI/MXene@CNTs could be regenerated by NaOH elution without impacting later usage, demonstrating high reusability. The study provided a cost-effective and ecologically beneficial method for preparing environmentally beneficial and reusable nanomaterials for harmful heavy-metal removal. Therefore, the nZVI/MXene@CNTs had a lot of promise for efficiently purifying toxic metal wastewater and might be employed as an ideal material for water pollution control.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app12168206/s1](https://www.mdpi.com/article/10.3390/app12168206/s1)]([https://www.mdpi.com/article/10.3390/app12168206/s1](https://www.mdpi.com/article/10.3390/app12168206/s1)), Table S1: Comparison of As(III) removal performance of nZVI/MXene@CNTs and other materials; Table S2: The fitting parameters of pseudo-first-order and pseudo-second-order kinetic models for As(III) adsorption by nZVI/MXene@CNTs; Table S3: The fitting parameters of Langmuir and Freundlich isotherm models for As(III) adsorption by nZVI/MXene@CNTs; Table S4 The fitting parameters of thermodynamic model for As(III) adsorption by nZVI/MXene@CNTs. References [67; 68] are cited in the supplementary materials.  
Figure 7: The possible removal mechanism of As(III) by nZVI/MXene@CNTs.  
**Author Contributions:** R.C.: Conceptualization, Writing--review and editing; S.L. ([PERSON]): Writing--original draft; S.L. ([PERSON]): Investigation, Data curation; S.W.: Methodology, Project administration; P.W.: Supervision; G.Z.: Software; W.W.: Formal analysis, Writing--review and editing. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by [the Natural science Foundation of Hunan Province] grant number [2022]J31014], [Hunan Provincial Key Research Plan Program of China] grant number [2021 GK4059 and 2020 SK2006] and [the project fund of degree and graduate education reform] grant number [2019]G001]. And the APC was funded by [2022]J31014 and 2020 SK2006].  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Data sharing not applicable.  
**Acknowledgments:** This work was supported by the Natural Science Foundation of Hunan Province (2022 JJ31014), Hunan Provincial Key Research Plan Program of China (Grant Numbers 2021 GK4059 and 2020 SK2006) and the project fund of degree and graduate education reform (2019)G001). The authors would like to extend special thanks to the editor and the anonymous reviewers for their constructive comments and suggestions for improving the quality of the paper.  
**Conflicts of Interest:** The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.