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Herein, we report terahertz (THz) shielding of flexible MXene (Ti3C2Tx)/MWCNT/PVA polymer composite films by using THz time-domain spectroscopy (THz-TDS) in 0.1–2.0 THz frequency range. The polymer composite with 42 µm thickness exhibited an excellent shielding effectiveness of 36 dB at 2 THz which is much higher than most of the reported materials for THz shielding with comparable thickness. The absorption coefficient increases from 100 cm−1 for pristine PVA to ~ 600 cm−1 for 20 wt% MXene/1.5 wt% MWCNT/PVA composite. The high THz shielding of flexible MXene/MWCNT/polymer composite is ascribed to the good electrical conductivity and interfacial synergistic effect of 1D/2D nanostructures that promoted the shielding of electromagnetic waves. Our simple solution casting methodology for fabrication of thin films and subsequent high THz shielding opens possibilities to design MXene-based polymer composites for THz applications. [ABSTRACT FROM AUTHOR]

Industrial utilization of nuclear resources greatly depends on the effective treatment of nuclear waste. The efficient removal of radioactive nuclides from liquid effluents by using different adsorbents has thus become crucial. Herein, for the first time, two-dimensional transition metal carbides (MXenes) are investigated as scavengers of cesium (Cs+) from contaminated water. Due to the combined advantages of the layered structure and the presence of heterogeneous sites (hydroxyl, oxygen and fluorine groups), the adsorbent reached the steady state within 1 min with the maximum Cs+ adsorption capacity of 25.4 mg g−1 at room temperature. The kinetics studies of the Cs+ scavenging process demonstrated that the adsorption of Cs+ followed the pseudo-second-order model whereas the adsorption equilibrium data obeyed the Freundlich model. Thermodynamic studies revealed that the adsorption process was endothermic. The adsorbent showed an excellent Cs+ removal efficiency in neutral to slightly alkaline solutions. Moreover, it can retain Cs+ even in the presence of a high concentration of competing cations (Li+, Na+, K+, Mg2+ and Sr2+). The Cs+ loaded adsorbent was regenerated with a 0.2 M HCl solution and reused at least five times for over 91% removal of contaminants. [ABSTRACT FROM AUTHOR]