Synergistic adsorption-reduction mechanism of magnetic Fe3O4@Ti3AlC2 composites for high-efficiency uranium (VI) remediation in aqueous systems

Background

Uranium(VI) contamination poses severe environmental and health risks due to its high mobility and toxicity. Existing remediation strategies face challenges in efficiency and scalability. This study addresses these limitations by developing a magnetic Fe₃O₄@Ti₃AlC₂ composite, leveraging synergistic adsorption-reduction mechanisms for effective U(VI) removal.

Methods

The composite was synthesized via co-precipitation, integrating Fe₃O₄ nanoparticles onto Ti₃AlC₂ substrates. Batch adsorption experiments evaluated U(VI) removal efficiency under varied pH, temperature, and coexisting ion conditions. Material characterization employed SEM, TEM, XRD, FTIR, XPS, and BET analysis to elucidate structural and mechanistic properties.

Significant Findings

Optimal adsorption occurred at pH 7 with a maximum capacity of 151.70 mg/g, driven by chemisorption and multilayer adsorption on heterogeneous surfaces, as confirmed by pseudo-second-order kinetics and Freundlich isotherm models. Mechanistic analyses revealed U(VI) immobilization through redox reactions (partial reduction to U(IV)) and complexation with surface functional groups (e.g., Ti–O, C = O). The composite demonstrated rapid magnetic separation, recyclability, and compatibility with natural groundwater pH, eliminating the need for rigorous pH adjustment. Notably, coexisting Cu²⁺ enhanced adsorption, while Pb²⁺ and organic macromolecules inhibited performance. These findings establish Fe₃O₄@Ti₃AlC₂ as a sustainable, high-efficiency adsorbent for uranium remediation, offering scalable applications in wastewater treatment and environmental restoration.