Dual-drive interfacial engineering on Ti3C2Tx MXene via plasma and covalent grafting for enhanced uranium extraction

Efficient and selective extraction of uranium (U(VI)) from complex seawater remains a critical challenge. This study proposes a dual-drive interfacial engineering strategy integrating eco-friendly plasma modification with covalent grafting to fabricate an advanced amidoxime modified MXene-based adsorbent. Hydrogen/argon plasma treatment significantly enhanced the wettability and surface hydroxyl reactivity of Ti 3 C 2 T x (TC) substrate. Subsequently, amidoxime (AO) groups were covalently anchored via a diazonium salt reaction followed by hydrothermal treatment, successfully constructing the AO/TC-H composite. The resultant material exhibited a remarkable maximum U(VI) adsorption capacity (760.18 mg·g −1 ), maintaining high efficiency across a broad pH range. Furthermore, AO/TC-H demonstrated robust cyclic stability, retaining over 87% of its initial adsorption capacity after five consecutive adsorption-desorption cycles. Notably, even in the presence of high-concentration competing vanadium, AO/TC-H preserved 68.9% of its U(VI) adsorption capacity, underscoring its exceptional selectivity. Density functional theory (DFT) calculations further elucidated the synergistic coordination mechanisms of hydroxyl and amidoxime groups with uranyl ions at the microscopic level. This work not only establishes a versatile, eco-friendly paradigm for the precise surface functionalization of 2D materials, but also provides a promising candidate for the practical deployment of seawater uranium extraction.