Two-Dimensional MXene as a Promising Adsorbent for Trihalomethanes Removal: A Density-Functional Theory Study

Islam Gomaa; Nasser Mohammed Hosny; Hanan Elhaes; Hend A Ezzat; Maryam G Elmahgary; Medhat A Ibrahim

doi:10.3390/nano14050454

Two-Dimensional MXene as a Promising Adsorbent for Trihalomethanes Removal: A Density-Functional Theory Study

Nanomaterials (Basel). 2024 Feb 29;14(5):454. doi: 10.3390/nano14050454.

Authors

Islam Gomaa^{1

2}, Nasser Mohammed Hosny², Hanan Elhaes³, Hend A Ezzat⁴, Maryam G Elmahgary^{5

6}, Medhat A Ibrahim^{7

8}

Affiliations

¹ Nanotechnology Research Centre (NTRC), The British University in Egypt (BUE), Suez Desert Road, El-Sherouk 11837, Egypt.
² Department of Chemistry, Faculty of Science, Port Said University, Port Said 42522, Egypt.
³ Physics Department, Faculty of Women for Arts, Science and Education, Ain Shams University, Cairo 11757, Egypt.
⁴ Nano Unit, Space Lab, Solar and Space Research Department, National Research Institute of Astronomy and Geophysics (NRIAG), Helwan 11421, Egypt.
⁵ Chemical Engineering Department, The British University in Egypt (BUE), El Sherouk 11837, Egypt.
⁶ Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
⁷ Spectroscopy Department, National Research Centre, 33 El-Bohouth St., Dokki 12622, Egypt.
⁸ Molecular Spectroscopy and Modeling Laboratory, Centre of Excellence for Advanced Science, National Research Centre, 33 El-Bohouth St., Dokki 12622, Egypt.

Abstract

This groundbreaking research delves into the intricate molecular interactions between MXene and trihalomethanes (THs) through a comprehensive theoretical study employing density-functional theory (DFT). Trihalomethanes are common carcinogenic chlorination byproducts found in water sanitation systems. This study focuses on a pristine MXene [M_n+1·X_n] monolayer and its various terminal [T_x] functional groups [M_n+1·X_nT_x], strategically placed on the surface for enhanced performance. Our investigation involves a detailed analysis of the adsorption energies of THs on different MXene types, with the MXene-Cl layer emerging as the most compatible variant. This specific MXene-Cl layer exhibits remarkable properties, including a total dipole moment (TDM) of 12.443 Debye and a bandgap of 0.570 eV, achieved through meticulous geometry optimization and computational techniques. Notably, THs such as trichloromethane (CHCl₃), bromide-chloromethane (CHBrCl₂), and dibromochloromethane (CHBr₂Cl) demonstrate the highest TDM values, indicating substantial changes in electronic and optical parameters, with TDM values of 16.363, 15.998, and 16.017 Debye, respectively. These findings highlight the potential of the MXene-Cl layer as an effective adsorbent and detector for CHF₃, CHClF₂, CHCl₃, CHBrCl₂, and CHBr₂Cl. Additionally, we observe a proportional increase in the TDM and bandgap energy, indicative of conductivity, for various termination atom combinations, such as Mxene-O-OH, Mxene-O-F, Mxene-O-Cl, Mxene-OH-F, Mxene-F-Cl, and Mxene-OH-Cl, with bandgap energies measured at 0.734, 0.940, 1.120, 0.835, and 0.927 eV, respectively. Utilizing DFT, we elucidate the adsorption energies of THs on different MXene surfaces. Our results conclusively demonstrate the significant influence of the termination atom nature and quantity on MXene's primitive TDM value. This research contributes to our understanding of MXene-THs interactions, offering promising avenues for the development of efficient adsorbents and detectors for THs. Ultimately, these advancements hold the potential to revolutionize water sanitation practices and enhance environmental safety.

Keywords: DFT; MESP; MXene (Mn+1·XnTx); TDM; halomethanes (THs).

Grants and funding

This research received no external funding.