MXsorption of mercury: Exceptional reductive behavior of titanium carbide/carbonitride MXenes

Asif Shahzad; Kashif Rasool; Jibran Iqbal; Jiseon Jang; Youngsu Lim; Bolam Kim; Jae-Min Oh; Dae Sung Lee

doi:10.1016/j.envres.2021.112532

MXsorption of mercury: Exceptional reductive behavior of titanium carbide/carbonitride MXenes

Environ Res. 2022 Apr 1:205:112532. doi: 10.1016/j.envres.2021.112532. Epub 2021 Dec 9.

Authors

Asif Shahzad¹, Kashif Rasool², Jibran Iqbal³, Jiseon Jang⁴, Youngsu Lim⁵, Bolam Kim⁵, Jae-Min Oh⁶, Dae Sung Lee⁷

Affiliations

¹ Department of Energy and Materials Engineering, Dongguk University, Seoul, 04620, Republic of Korea.
² Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Qatar Foundation, P.O. Box 5824, Doha, Qatar.
³ College of Natural and Health Sciences, Zayed University, Abu Dhabi, 144534, United Arab Emirates.
⁴ R&D Institute of Radioactive Wastes, Korea Radioactive Waste Agency, 174 Gajeong-ro, Yuseong-gu, Daejeon, 34129, Republic of Korea.
⁵ Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea.
⁶ Department of Energy and Materials Engineering, Dongguk University, Seoul, 04620, Republic of Korea. Electronic address: jaemin.oh@dongguk.edu.
⁷ Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea. Electronic address: daesung@knu.ac.kr.

PMID: 34896083
DOI: 10.1016/j.envres.2021.112532

Abstract

Two-dimensional (2D) transition metal carbides and nitrides (MXenes) have drawn considerable attention for application in the field of environmental remediation. In this study, we report the simultaneous reductive-adsorption behavior of Ti₃CNT_x for toxic metal ion Hg²⁺ ion in the aqueous phase. 2D Ti₃CNT_x and Ti₃C₂T_x MXene nanosheets were synthesized by exfoliation of Ti₃AlCN and Ti₃AlC₂ MAX phases, respectively. Various characteristics analysis confirmed the successful fabrication of MAX phases and their exfoliation into MXenes. The fabricated MXene nanosheets were used to investigate their Hg²⁺ removal, Hg²⁺ intercalation, and surface interaction mechanism efficiencies. Both MXenes were found to adsorb and reduce a large amount of Hg²⁺. Analytical techniques such as X-ray powder diffraction, field emission transmission electron microscopy, zeta-potential analyses, and X-ray photoelectron spectroscopy were used to investigate the material characteristics and structural changes after uptake of Hg²⁺. The quantitative investigation confirmed the interaction of bimetal and hydroxyl groups with Hg²⁺ using electrostatic interactions and adsorption-coupled reduction. In addition, both MXenes exhibited extraordinary Hg ion removal capabilities in terms of fast kinetics with an excellent distribution coefficient (K_d^Hg) up to 1.36 × 10⁺⁹. Based on batch adsorption results, Ti₃C₂T_x and Ti₃CNT_x exhibited removal capacities of 5473.13 and 4606.04 mg/g, respectively, for Hg²⁺, which are higher than those of previous Hg adsorbents.

Keywords: Hg reduction; MXene; MXsorption; Titanium carbonitride; Water decontamination.

Publication types

Research Support, Non-U.S. Gov't