Enhanced arsenic stabilization via halloysite-supported iron oxide nanoreactors for sustainable environmental remediation

Iron-based materials for arsenic (As) immobilization suffer from low adsorption capacity and instability under dynamic conditions. To address these limitations, we developed iron oxide-functionalized halloysite nanotube (Fe-HNT) nanoreactors by confining iron oxide nanoparticles within halloysite nanotube (HNT) lumens for enhanced As stabilization. Fe-HNT exhibits exceptional As stabilization ability, outperforming conventional nZVI-HNT and Phoslock in both aqueous and soil systems. Moreover, the encapsulation of Fe oxides within HNT's lumen enhanced Fe-HNT's resistance to environmental interference by approximately 40 % compared to conventional materials. Notably, Fe-HNT demonstrated exceptional long-term stability of As immobilization, retaining > 96 % As(III) and > 82 % As(V) immobilization efficiency and excellent acid corrosion resistance after five acid rain leaching (pH 3.2) and dry-wet cycles. Life cycle assessment confirmed Fe-HNT's reduced environmental burdens, with significant mitigation of impacts on human health damage, ecosystem quality degradation, and resource scarcity depletion relative to nZVI-HNT and Phoslock. This work provides fundamental insights into nanoconfinement engineering of clay-based reactors and advances the development of sustainable remediation technologies for As contamination.